Faculty Profiles - TSUCHIKAWA, Satoru

Improvement of hyperspectral imaging signal quality using filtering technique Reviewed Open Access

Zhou, JS; Ma, T; Tsuchikawa, S; Inagaki, T

CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS Vol. 261 2025.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemometrics and Intelligent Laboratory Systems

This paper proposes to improve signal quality in hyperspectral imaging (HSI) on the basis of noise analysis and filtering method. HSI technology enables nondestructive and precise analysis in agriculture and food industries by acquiring high-resolution images over multiple wavelengths, but the identification and removal of noise in the signal is a challenge. In this study, HSI measurement data of sucrose solution samples of different concentrations were used as experimental subjects. The outliers outside the three-fold standard deviation range of all data were identified as noise and a filtering method using noise mask and Wavelet transform was proposed. By evaluating the effect of the filtering method on noise reduction, we conducted qualitative and quantitative analysis and comparison, mainly through statistical methods and the limits of detection (LOD), LODmin and LODmax. The experiment results show that the proposed method is useful in removing noise, reducing the detection limit when applying Partial Least Squares (PLS) and improving the HSI signal quality. This is expected to improve the accuracy of nondestructive analysis using HSI data.

DOI： 10.1016/j.chemolab.2025.105386

Evaluating goji berry (Lycium barbarum L.) quality change during storage using color and fluorescence imaging system Reviewed

Chen, QY; Ma, T; Wei, NS; Fan, YL; Zhang, W; Wang, ZY; Tsuchikawa, S; Chen, Y; Chen, J

JOURNAL OF FOOD COMPOSITION AND ANALYSIS Vol. 141 2025.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Food Composition and Analysis

The consumption of fresh goji berries has become an increasingly popular trend in China. However, they have a relatively short shelf life and are highly susceptible to rapid deterioration. This study measured the excitation-emission matrix (EEM) of goji berries during storage. Based on these results, a system was developed that integrates UVA LED light sources and an industrial camera to capture both color and fluorescence images. In the experiment, color and fluorescence images of the berries were captured at 24-hour intervals, and their firmness was assessed. The HSV, RGB, and Lab color space components of the images were extracted. The relationships between these color components and goji berry quality were analyzed using simple linear regression and partial least squares regression (PLSR). A regression model was developed to evaluate berry firmness. The PLSR model's coefficients of determination (R²) for calibration, prediction, and cross-validation were 0.91, 0.89, and 0.86, respectively, with corresponding root mean square errors (RMSE) of 0.11, 0.13, and 0.14. The results show that the proposed imaging detection system enables non-contact firmness measurement of fresh goji berries, offering a cost-effective solution with significant potential for broader applications.

DOI： 10.1016/j.jfca.2025.107342

Examination of SWIR hyperspectral imaging for estimating corewood – outerwood transition age for Douglas-fir grown at different planting densities Reviewed

Design and development of a portable Vis-NIR spatially resolved spectroscopic device for nondestructive and rapid evaluation of growth stress in standing trees Reviewed Open Access

Te Ma, Hiroyuki Yamamoto, Takusu Kajimura, Tetsuya Inagaki, Satoru Tsuchikawa

Computers and Electronics in Agriculture Vol. 231 page： 110014 - 110014 2025.4

Ighoyivwi Onakpoma, Te Ma, Laurence R. Schimleck, Tetsuya Inagaki, Satoru Tsuchikawa

Holzforschung Vol. 79 ( 2-3 ) page： 93 - 101 2025.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Walter de Gruyter GmbH

Abstract

Silvicultural practices, particularly planting density (PD), significantly affect the wood quality of plantation-grown trees by influencing the age of transition from corewood to outerwood. Determining transition age (TA) is challenging. Near infrared hyperspectral imaging was used to assess the age of transition from corewood to outerwood in Douglas-fir (Pseudotsuga menziesii) grown under different PD. Wood samples were taken from permanent research plots with six PD ranging from 2,990 to 248 stems/hectare. Twenty trees were destructively sampled at age 25, and wood discs were collected at 10 % of total tree height. Pith-to-bark radial strips obtained from each disc were scanned using a compovision hyperspectral imaging system (1,002–2,350 nm). Partial least square discriminant analysis (PLS-DA) models were fitted to approximate TA using hyperspectral data representative of corewood and outerwood. PD influenced TA and the duration over which it occurred. Average age of transition was estimated to vary from 10 (closest spacing) to 14 years (widest). Closely spaced trees exhibited an abrupt transition, while widely spaced trees had a more gradual transition. However, PLS-DA likely underestimated the transition duration for widely spaced trees, as their average ring densities did not yet match those typical of outerwood based on X-ray densitometry data.

DOI： 10.1515/hf-2024-0058

Intelligent monitoring of post-processing characteristics in 3D-printed food products: A focus on fermentation process of starch-gluten mixture using NIR and multivariate analysis Reviewed

Other Link： https://www.degruyter.com/document/doi/10.1515/hf-2024-0058/pdf

Jiang, Q; Bao, YR; Ma, T; Tsuchikawa, S; Inagaki, T; Wang, H; Jiang, H

JOURNAL OF FOOD ENGINEERING Vol. 388 2025.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Food Engineering

The production of three-dimensional (3D)-printed food products requires not only optimal 3D-printing adaptability but also appropriate post-processing characteristics. This study aimed to use near infrared (NIR) spectroscopy to predict the rheological properties of 3D-printed dough, enabling intelligent monitoring of the dough's fermentation process. Utilizing support vector machine (SVM) classification model, the fermentation stages can be classified as under-fermentation, complete fermentation, and over-fermentation. Employing preprocessing methods with Synergy Interval Partial Least Square-Competitive Adaptive Reweighted Sampling (SIPLS-CARS) algorithm, 27, 39, 23, and 27 key wavelengths were filtered from the raw NIR spectral data, corresponding to the prediction of storage modulus (G′), loss modulus (G″), complex viscosity (η∗), and loss factor (tan δ), respectively. Quantitatively, SVM (Support Vector Machine) regression outperformed Partial Least Squares (PLS) with Rc2 values (0.95, 0.94, 0.94) and Rp2 values (0.93, 0.93, 0.94) for G′, G″, and η∗. NIR spectra-based predictive models demonstrated superior performance compared to rheo-fermentation properties models. In summary, these findings show the potential of NIR spectroscopy as a rapid tool for predicting the fermentation progress of 3D-printed doughs.

DOI： 10.1016/j.jfoodeng.2024.112357

The effects of growth rate on the age dependent variation of wood properties evaluated by differential geometry Reviewed

Development of a time-resolved laser-induced fluorescence fingerprinting method for detecting low-level adulteration in extra virgin olive oil Reviewed Open Access

Te Ma, Hao Jiang, Satoru Tsuchikawa, Tetsuya Inagaki

Food Chemistry Vol. 465 ( Pt 2 ) page： 142125 - 142125 2025.2

Enhanced detection of early bruises in apples using near-infrared hyperspectral imaging with geometrical influence correction for universal size adaptation Reviewed Open Access

Bin Li, Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Postharvest Biology and Technology Vol. 219 page： 113282 - 113282 2025.1

The Detection of Pest Contaminants in Chocolate Using Visible-Near-Infrared Single-Pixel Imaging Technology Reviewed Open Access

Hidemasa Taketoshi, Tetsuya Inagaki, Satoru Tsuchikawa, Te Ma

Foods Vol. 14 ( 2 ) 2025.1

Language：English Publishing type：Research paper (scientific journal)

Food safety is gaining increasing attention worldwide. Currently, low-density organic foreign objects such as insects are extremely challenging to detect using conventional metal detectors and X-ray inspection systems. This study aimed to develop a visible-near-infrared single-pixel imaging (Vis-NIR-SPI) method to detect small insects inside food. The advantages of Vis-NIR light include its ability to analyze samples non-destructively and measure multiple components simultaneously and quickly, while SPI is robust against dark noise, high scattering, and high equipment costs. The experimental results demonstrated that (1) the newly designed system effectively reduces scattering effects from the highly scattering sample (intralipid 20%), allowing for the capture of information beyond the capabilities of a charge-coupled-device camera; (2) insects positioned behind ham and bread were readily detectable using the imaging reconstruction algorithm; and (3) even for chocolate samples with very high light absorption, only 1 uncontaminated sample out of 100 was mistakenly classified as contaminated, yielding an overall accuracy of 99%. This high level of accuracy underscores the potential of the Vis-NIR-SPI method to provide reliable detection while maintaining sample integrity. Furthermore, this method is cost-effective, offering a practical and efficient solution to improve quality control processes and consumer trust in the food industry.

DOI： 10.3390/foods14020206

Takaaki Fujimoto, Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Industrial Crops and Products Vol. 222 2024.12

Language：English Publishing type：Research paper (scientific journal)

A correct understanding of the variations seen in wood properties with tree age is of great importance for both the forestry and timber industries. However, this phenomenon is complex because of the differences between individuals and the variations associated with multiple wood properties. In this study, we have identified age-dependent changes in the state of wood as a surface that contains comprehensive information on the coupled variation of multiple properties in many individuals. By comparing the geometric quantities of the surface between sample groups with different growth rates caused by silvicultural treatments, we have discussed the ideal forest management in terms of wood quality and forest ecosystems. The slow-growing group showed larger Gaussian curvatures of the surface and a more tortuous and longer geodesic than the fast-growing group, resulting in less energy loss during tree growth. Assuming that processes with high symmetry are more sustainable, the characteristic class representing the global structure of the growth process indicates that the slow-growing group follows a more sustainable process than the fast-growing group. These results indicate that it is ideal for trees to grow slowly, in terms of variation of wood properties and forest ecosystem. Because the geometric quantities are invariant under coordinate transformations, the proposed methods provide us with the intrinsic behavior of the tree growth process independent of a specific coordinate system, that is, a concrete space spanned by the measured wood properties.

DOI： 10.1016/j.indcrop.2024.119596

Enhanced quantification of chlorophyll a and its degradation products in olive oil using time-resolved laser-induced fluorescence fingerprint analysis Reviewed Open Access

Te Ma, Hao Jiang, Satoru Tsuchikawa, Tetsuya Inagaki

Food Chemistry Vol. 460 ( Pt 3 ) page： 140656 2024.12

Language：English Publishing type：Research paper (scientific journal)

Potential errors in the fluorescence analysis of chlorophylls and their degradation products, primarily due to spectral overlap and inner filter, are widely acknowledged. This study aimed to devise a sensitivity-enhanced technique for the concurrent quantification of chlorophyll a and its degradation products while minimizing effects from type-B chlorophylls. Initially, a time-resolved laser-induced fluorescence spectroscopic system was designed and tested on stardard chlorophyll samples. The origins, implications, and mitigation strategies of spectral overlap and the inner filter effect on the measured fluorescence intensity were thoroughly examined. Then, this methodology was proved to be efficacious within complex liquid matrices derived from olive oil. The experimental outcomes not only shed additional light on the mechanisms of chlorophyll fluorescence overlap and the inner filter effect, but also establish a general framework for developing spectrally and timely resolved fluorescence fingerprint analysis for the simultaneous quantification of chlorophylls and their degradation products at high concentrations.

DOI： 10.1016/j.foodchem.2024.140656

Validation Study on the Practical Accuracy of Wood Species Identification via Deep Learning from Visible Microscopic Images Reviewed Open Access

Te Ma, Fumiya Kimura, Satoru Tsuchikawa, Miho Kojima, Tetsuya Inagaki

BioResources Vol. 19 ( 3 ) page： 4838 - 4851 2024.8

Language：English Publishing type：Research paper (scientific journal)

This study aimed to validate the accuracy of identifying Japanese hardwood species from microscopic cross-sectional images using convolutional neural networks (CNN). The overarching goal is to create a versatile model that can handle microscopic cross-sectional images of wood. To gauge the practical accuracy, a comprehensive database of microscopic images of Japanese hardwood species was provided by the Forest Research and Management Organization. These images, captured from various positions on wood blocks, different trees, and diverse production areas, resulted in substantial intra-species image variation. To assess the effect of data distribution on accuracy, two datasets, D1 and D2, representing a segregated and a non-segregated dataset, respectively—from 1,000 images (20 images from each of the 50 species) were compiled. For D1, distinct images were allocated to the training, validation, and testing sets. However, in D2, the same images were used for both training and testing. Furthermore, the influence of the evaluation methodology on the identification accuracy was investigated by comparing two approaches: patch evaluation and E2 image evaluation. The accuracy of the model for uniformly sized images was approximately 90%, whereas that for variably sized images it was approximately 70%.

DOI： 10.15376/biores.19.3.4838-4851

Cellulose crystalline structure and thermal properties under heat treatment: An investigation by two-dimensional correlation of near infrared spectroscopy and differential scanning calorimetry Reviewed

Analysis of the Pomelo Peel Essential Oils at Different Storage Durations Using a Visible and Near-Infrared Spectroscopic on Intact Fruit Reviewed Open Access

Sirisomboon, P; Duangchang, J; Phanomsophon, T; Lapcharoensuk, R; Shrestha, BP; Kasemsamran, S; Thanapase, W; Pornchaloempong, P; Tsuchikawa, S

FOODS Vol. 13 ( 15 ) 2024.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Foods

Pomelo fruit pulp mainly is consumed fresh and with very little processing, and its peels are discarded as biological waste, which can cause the environmental problems. The peels contain several bioactive chemical compounds, especially essential oils (EOs). The content of a specific EO is important for the extraction process in industry and in research units such as breeding research. The explanation of the biosynthesis pathway for EO generation and change was included. The chemical bond vibration affected the prediction of EO constituents was comprehensively explained by regression coefficient plots and x-loading plots. Visible and near-infrared spectroscopy (VIS/NIRS) is a prominent rapid technique used for fruit quality assessment. This research work was focused on evaluating the use of VIS/NIRS to predict the composition of EOs found in the peel of the pomelo fruit (Citrus maxima (J. Burm.) Merr. cv Kao Nam Pueng) following storage. The composition of the peel oil was analyzed by gas chromatography–mass spectrometry (GC-MS) at storage durations of 0, 15, 30, 45, 60, 75, 90, 105 and 120 days (at 10 °C and 70% relative humidity). The relationship between the NIR spectral data and the major EO components found in the peel, including nootkatone, geranial, β-phellandrene and limonene, were established using the raw spectral data in conjunction with partial least squares (PLS) regression. Preprocessing of the raw spectra was performed using multiplicative scatter correction (MSC) or second derivative preprocessing. The PLS model of nootkatone with full MSC had the highest correlation coefficient between the predicted and reference values (r = 0.82), with a standard error of prediction (SEP) of 0.11% and bias of 0.01%, while the models of geranial, β-phellandrene and limonene provided too low r values of 0.75, 0.75 and 0.67, respectively. The nootkatone model is only appropriate for use in screening and some other approximate calibrations, though this is the first report of the use of NIR spectroscopy on intact fruit measurement for its peel EO constituents during cold storage.

DOI： 10.3390/foods13152379

Evaluating Soluble Solids in White Strawberries: A Comparative Analysis of Vis-NIR and NIR Spectroscopy Reviewed Open Access

Hayato Seki, Haruko Murakami, Te Ma, Satoru Tsuchikawa, Tetsuya Inagaki

Foods Vol. 13 ( 14 ) 2024.7

Language：English Publishing type：Research paper (scientific journal)

In recent years, due to breeding improvements, strawberries with low anthocyanin content and a white rind are now available, and they are highly valued in the market. Strawberries with white skin color do not turn red when ripe, making it difficult to judge ripeness. The soluble solids content (SSC) is an indicator of fruit quality and is closely related to ripeness. In this study, visible–near-infrared (Vis-NIR) spectroscopy and near-infrared (NIR) spectroscopy are used for non-destructive evaluation of the SSC. Vis-NIR (500–978 nm) and NIR (908–1676 nm) data collected from 180 samples of “Tochigi iW1 go” white strawberries and 150 samples of “Tochigi i27 go” red strawberries are investigated. The white strawberry SSC model developed by partial least squares regression (PLSR) in Vis-NIR had a determination coefficient R2p of 0.89 and a root mean square error prediction (RMSEP) of 0.40%; the model developed in NIR showed satisfactory estimation accuracy with an R2p of 0.85 and an RMSEP of 0.43%. These estimation accuracies were comparable to the results of the red strawberry model. Absorption derived from anthocyanin and chlorophyll pigments in white strawberries was observed in the Vis-NIR region. In addition, a dataset consisting of red and white strawberries can be used to predict the pigment-independent SSC. These results contribute to the development of methods for a rapid fruit sorting system and the development of an on-site ripeness determination system.

DOI： 10.3390/foods13142274

Siti Hanifah Mahdiyanti, Masaki Asaoka, Tetsuya Inagaki, Satoru Tsuchikawa

Journal of Near Infrared Spectroscopy Vol. 32 ( 3 ) page： 113 - 124 2024.6

Language：English Publishing type：Research paper (scientific journal)

This study investigated the thermal behavior and crystallinity of microcrystalline cellulose (MCC) under heat treatment using near infrared (NIR) spectroscopy and differential scanning calorimetry (DSC). The results showed that heat treatment reduced the crystallinity and thermal stability of MCC at a certain point, and that the changes in the chemical components and structure of MCC were correlated with the heat flow measured by DSC. The analysis was performed using two-dimensional correlation spectroscopy (2DCOS), which revealed the simultaneous changes in the NIR second-derivative spectra and the DSC thermograms of heat-treated MCC. Linear regression analysis showed a high r2 value of 0.90 between the DSC enthalpy change at 270 °C–400°C and the PC1 score of NIR second-derivative spectra at 7500–4100 cm−1. The 2DCOS synchronous map showed a positive correlation at 6656–6229 cm−1 with a r value of 0.70–0.98 for the endothermic reaction, and a negative correlation at 6229; 5620; 5401; 4844; 4535 cm−1 with a r value of −0.90 to −0.99 for the exothermic reaction. This study extended the knowledge on the thermal behavior and decomposition mechanisms of heat-treated MCC, and provided a useful method for cellulose characterization and identification.

DOI： 10.1177/09670335241257649

Effect of dielectric barrier discharge (DBD) plasma treatment on physicochemical and 3D printing properties of wheat starch Reviewed

Ma, S; Ma, T; Tsuchikawa, S; Inagaki, T; Wang, H; Jiang, H

INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol. 269 ( Pt 2 ) page： 132159 2024.6

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Biological Macromolecules

In recent years, the focus has shifted towards carbohydrate-based hydrogels and their eco-friendly preparation methods. This study involved an investigation into the treatment of wheat starch using dielectric barrier discharge (DBD) plasma technology over varying time gradients (0, 2, 5, 10, 15, and 20 min). The objective was to systematically examine the impact of different treatment durations on the physicochemical properties of wheat starch and the suitability of its gels for 3D printing. Morphology of wheat starch remained intact after DBD treatment. However, it led to a reduction in the amylose content, molecular weight, and crystallinity. This subsequently resulted in a decrease in the pasting temperature and viscosity. Moreover, the gels of the DBD-treated starch exhibited superior 3D printing performance. After a 2-min DBD treatment, the 3D printed samples of the wheat starch gel showed no significant improvements, as broken bars were evident on the surface of the 3D printed graphic, whereas DBD-20 showed better printing accuracy and surface structure, compared to the original starch without slumping. These results suggested that DBD technology holds potential for developing new starch-based gels with impressive 3D printing properties.

DOI： 10.1016/j.ijbiomac.2024.132159

Terahertz time-domain spectroscopy as a novel tool for crystallographic analysis in cellulose: tracking lattice changes following physical treatments Reviewed Open Access

Wang, H; Aoki, D; Teramoto, Y; Tsuchikawa, S; Inagaki, T

CELLULOSE Vol. 31 ( 7 ) page： 4085 - 4098 2024.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Cellulose

The authors’ series of studies aimed to explore the potential of terahertz time-domain spectroscopy (THz-TDS) in cellulose crystallographic studies, since THz radiation can detect most intermolecular vibrations and respond to lattice phonons. In this study, we tracked changes in four types of cellulose after ball milling. As the planetary ball milling time increases, it is observed through electron microscopy that the four types of cellulose particles are gradually destroyed into finer particles, while gel permeation chromatography can prove that the molecular weight gradually decreases after ball milling and the dispersity gradually approaches one, which indicates that the dispersion of the material was reduced. The most fascinating observation was made by THz-TDS, that is we have confirmed that after ball milling, the absorption characteristics of cellulose I and II in cellulose I treated with 10% NaOH (crystalline partial transition from cellulose I to II) exhibited an opposite trend. Specifically, the absorption of cellulose II at 2.40THz and 2.77THz increased, while the absorption of cellulose I at 2.11THz and 3.04THz decreased after ball milling, which suggests an increased conversion rate of cellulose I to cellulose II post-milling. Cellulose with different crystalline allomorphs shows different characteristic absorption in the THz region, and the peak position will not change even after the ball milling, only the absorption intensity changes. Although it can be observed through the most traditional X-ray diffraction method that the crystallinity index of all cellulose samples gradually decreases after ball milling. However, different from the THz results, the change after ball milling of cellulose I treated with 10% NaOH is only reflected in very subtle pattern changes, that is, the peak close to the 200 crystalline plane position is slightly shifted after ball milling.

DOI： 10.1007/s10570-024-05834-8

Development of a sensitivity-enhanced fluorescence lifetime spectroscopic method for nondestructive quality monitoring of mature tomatoes during storage Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Scientia Horticulturae Vol. 330 2024.4

Language：English Publishing type：Research paper (scientific journal)

The decay of fluorescence lifetime (FLT) is an absolute indication for observing the environment surrounding the fluorescent molecules. This study presents the characterization of fluorescence intensity and the FLT in tomatoes, spanning from the green to the red stage, using a novel time-resolved and laser-induced fluorescence (TRLIF) spectroscopic system. Furthermore, the applicability of this method was assessed for evaluating the postharvest quality of commercially acquired red tomatoes. The results collectively indicate a progressive decrease in the FLT of the red tomatoes throughout shelf-life storage. The average FLT loss decreased by approximately 17, 26, 32, and 38% after 1, 2, 3, and 4 d, respectively. Furthermore, the first principal component scores of the time-resolved spectra were confirmed to be stable for early quality degradation monitoring purposes. This investigation highlights that the devised TRLIF spectroscopic technique is a non-destructive and robust method for studying the degradation of fluorescent compounds. It facilitates an in-depth exploration of the underlying mechanisms behind the fluorescent phenomena in postharvest research.

DOI： 10.1016/j.scienta.2024.113059

Three-dimensional visualization and detection of early bruise in apple based on near-infrared hyperspectral imaging coupled with geometrical influence correction Reviewed

Li, B; Ma, T; Bai, LS; Inagaki, T; Seki, H; Tsuchikawa, S

POSTHARVEST BIOLOGY AND TECHNOLOGY Vol. 210 2024.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Postharvest Biology and Technology

Visible-near-infrared (Vis-NIR) spectral imaging holds great promise for the automatic detection of fruit defects. However, uneven brightness resulting from fruit geometry and the limitations of one-directional imaging significantly restrict the current detection to a limited area. This study presents a rotation measurement system that combines a line-scan NIR-hyperspectral imaging (HSI) camera with a laser profile. A total of 72 apple samples with bruises in the central and edge regions were prepared. A 360° scanning approach was employed to collect HSI and shape data from the entire surface of the samples over a 6-h post-bruising period. Height and angle corrections were applied to eliminate the surface geometric influences on the HSI data, resulting in improved reflectance spectrum uniformity. A two-step principal component analysis method was employed for image enhancement, followed by a straightforward bruise detection technique using global segmentation and connected-domain selection. The results demonstrated an overall improvement in bruise detection over time. Moreover, the correction significantly enhanced the detection accuracy. After 6 h of bruising, the corrected data achieved a classification accuracy of 90.3% and an identification rate of 83.3% for central bruises and 61.1% for edge bruises, whereas the uncorrected data yielded 70.8%, 58.3%, and 31.9%, respectively. Thus, this study successfully detected early bruising across the entire surface of apples and improved the detection in low-intensity edge areas. The proposed method has the potential to contribute to the comprehensive evaluation of agricultural products with irregular geometries.

DOI： 10.1016/j.postharvbio.2023.112753

Non-Destructive Near-Infrared Moisture Detection of Dried Goji (Lycium barbarum L.) Berry Reviewed Open Access

Kang, R; Ma, T; Tsuchikawa, S; Inagaki, T; Chen, J; Zhao, J; Li, DD; Cui, GP

HORTICULTURAE Vol. 10 ( 3 ) 2024.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Horticulturae

To detect the moisture of dried Goji (Lycium barbarum L.) berries nondestructively, a near-infrared (NIR) hyperspectral imager was used for experiments. NIR hyperspectral data were obtained and processed by standard normal variate (SNV) calculation using the MATLAB software v.R2016a. On the basis of the actual moisture of dried Goji berries, the predicted moisture was obtained based on the partial least squares (PLS) algorithm and a prediction model for the moisture of dried goji berries was established. It was found that the moisture of dried Goji berries was responsive to the NIR hyperspectral imager. The established prediction model could accurately predict the moisture of dried goji berries, and its R2-value was 0.9981. The results provide a theoretical basis for the design of non-destructive moisture-detecting equipment for dried Goji berries.

DOI： 10.3390/horticulturae10030302

Investigation of the effects of tableting parameters on reliable quantitative terahertz spectroscopy Reviewed

Yuan Su, Yang Xu, Han Wang, Te Ma, Satoru Tsuchikawa, Tetsuya Inagaki

Applied Physics A: Materials Science and Processing Vol. 130 ( 2 ) 2024.2

Language：English Publishing type：Research paper (scientific journal)

Particle size ratio, tablet thickness, and compaction pressure are three important tableting parameters that affect the obtained tablet spectrum. In this study, the single-factor test and response surface analysis (RSM) were adopted to examine how these three parameters and their interactions affect the analytical measurements performed over terahertz time-domain spectroscopy (THz-TDS). Tablet samples were composed of a different percent (wt-%) of acetylsalicylic acid within microcrystalline cellulose. Results indicate that change in absorption coefficient was found to be more obvious for a larger particle size ratio. Thinner tablets were sensitive to absorption coefficient effects created as the transmitted THz radiation propagates through the tablet interfaces. Compression pressure has a limited effect on the absorption coefficient. The particle size ratio had the largest effect on the coefficient of correlation of the quantitative regression model, followed by the compaction pressure, and the tablet thickness. In this study, the optimized tableting parameters were determined: tablet thickness of 0.48 mm, particle size ratio of about 1:1, and compaction pressure of 30 MPa. Under this condition, the R2 of the quantitative regression model of acetylsalicylic acid content was 0.971 and 0.998 at the range of acetylsalicylic acid mass fraction between 10 and 90 wt-%, 1 and 30 wt-%, respectively. This study provides a method to effectively reduce the scattering effect of spectral detection of tablets by improving the sample’s properties, to provide a reference for enhancing the reliability and accuracy of quantitative measurements.

DOI： 10.1007/s00339-024-07302-3

Primary assessment of macronutrients in durian (CV Monthong) leaves using near infrared spectroscopy with wavelength selection Reviewed

Three-dimensional modeling of moisture transport in wood using near-infrared hyperspectral imaging and X-ray computed tomography in conjunction with finite element analysis Reviewed Open Access

Zeng, WP; Fujimoto, T; Inagaki, T; Tsuchikawa, S; Ma, T

JOURNAL OF WOOD SCIENCE Vol. 70 ( 1 ) page： 9 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

In past studies, finite element analysis (FEA) methods have been used to simulate the thermal and moisture coupling of wood. However, challenges remain in achieving high-quality three-dimensional (3D) simulations, mainly because of the heterogeneous and complex structure of wood and its difficult-to-detect internal structure, which makes modeling challenging, in addition to the lack of robust experimental techniques to validate simulation results. In this study, the FEA simulation model was refined by combining X-ray computed tomography (CT) and near-infrared hyperspectral imaging (NIR-HSI). CT was used to probe the 3D density of wood, and a novel FEA tetrahedral mesh was constructed based on the results. The NIR-HSI method visualizes the moisture distribution during adsorption and desorption inside the wood. This result is then used to adjust the parameters of the FEA simulation model and as a reference value to evaluate the simulation results. The visualization and simulation results fit well with the theoretical properties. The simulation results can more accurately reflect the spatial distribution and transfer trend of wood moisture at different points in time. Therefore, the CT and NIR-HSI-based 3D heat and moisture-coupled FEA model of wood proposed in this study can be used as a basis for optimizing drying parameters to provide high-quality wood.

DOI： 10.1186/s10086-023-02120-2

Phanomsophon, T; Jaisue, N; Worphet, A; Tawinteung, N; Khurnpoon, L; Lapcharoensuk, R; Krusong, W; Pornchaloempong, P; Sirisomboon, P; Inagaki, T; Ma, T; Tsuchikawa, S

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY Vol. 304 page： 123398 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

Farmers would be able to regulate fertilization and produce quality durian if they knew the nutrient concentration in durian leaves. A long period of time for traditional nutritional content determination is needed. Therefore, near-infrared spectroscopy is a good method for nondestructive and quick nutrient content evaluation. The leaf sample matrices (fresh leaves, dried ground leaves, and dried ground leaf pellets) were scanned by Fourier transform near-infrared (FT-NIR) with a wavelength of 12,500–3,600 cm−1. Regression models were developed using partial least squares (PLS) with full wavelength, short wavelength, and selected wavelength by successive projections algorithm (SPA). In this study, the model for N and K concentration was acceptable and the prediction was considered good but for P content not had succeeded. As a result, the PLS-SPA model using fresh leaf samples for evaluating N content in durian leaves exhibited performance of r2 = 0.852, SEP = 0.14%, RPD = 2.63 and bias = −0.020%. The PLS-SPA model using dried ground leaf samples for evaluating K content in durian leaves exhibited performance of r2 = 0.820, SEP = 0.13%, RPD = 2.36 and bias = 0.006%. This research found that it is possible to apply NIR waves to predict N and K concentrations in durian leaves. It is not necessary to predict directly from the wavelengths associated with -N or -K bonds. Instead, NIR can measure them indirectly from the bonding of proteins, which are products formed by N and K. In addition, selecting the wavelength that is related to the value to be measured can produce results that are not significantly different from using full or short wavelengths. These models can assist farmers in rapidly predicting N and K content in durian leaves for immediate fertilizer adjustment.

DOI： 10.1016/j.saa.2023.123398

Classification of the Crosslink Density Level of Para Rubber Thick Film of Medical Glove by Using Near-Infrared Spectral Data Reviewed Open Access

Jongyingcharoen, JS; Howimanporn, S; Sitorus, A; Phanomsophon, T; Posom, J; Salubsi, T; Kongwaree, A; Lim, CH; Phetpan, K; Sirisomboon, P; Tsuchikawa, S

POLYMERS Vol. 16 ( 2 ) 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymers

Classification of the crosslink density level of para rubber medical gloves by using near-infrared spectral data combined with machine learning is the first time reported in this paper. The spectra of medical glove samples with different crosslink densities acquired by an ultra-compact portable MicroNIR spectrometer were correlated with their crosslink density levels, which were referencely evaluated by the toluene swell index (TSI). The machine learning protocols used to classify the 3 groups of TSI were specified as less than 80% TSI, 80–88% TSI, and more than 88% TSI. The 80–88% TSI group was the group in which the compounded latex was suitable for medical glove production, which made the glove specification comply with the requirements of customers as indicated by the tensile test. The results show that when comparing the algorithms used for modeling, the linear discriminant analysis (LDA) developed by 2nd derivative spectra with 15 k-best selected wavelengths fairly accurately predicted the class but was most reliable among other algorithms, i.e., artificial neural networks (ANN), support vector machines (SVM), and k-nearest neighbors (kNN), due to higher prediction accuracy, precision, recall, and F1-score of the same value of 0.76 and no overfitting or underfitting prediction. This developed model can be implemented in the glove factory for screening purposes in the production line. However, deep learning modeling should be explored with a larger sample number required for better model performance.

DOI： 10.3390/polym16020184

Application of Near-Infrared Spectroscopy to Forest and Wood Products Reviewed

Tsuchikawa, S; Inagaki, T; Ma, T

CURRENT FORESTRY REPORTS Vol. 9 ( 6 ) page： 401 - 412 2023.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Current Forestry Reports

Purpose of Review: Forest and wood products are often characterized by a uniformity of quality attributes, which necessitates the development of rapid and non-destructive quality evaluation methods to ensure their optimal quality. Near-infrared spectroscopy (NIRS) represents a highly suitable approach for the characterization of organic compounds, and is generally combined with sophisticated multivariate analysis methods. This review article presents a range of scientific and technical reports showcasing the successful use of NIRS for evaluating forest and wood products, mainly published within the past 5 years. Recent Findings: Continuous advancements in spectral imaging techniques and the integration of big-data analytics have greatly enhanced the capabilities of NIR instrumentation, enabling its widespread application across diverse fields. Although NIR spectral imaging methods do have some limitations when it comes to online grading, they can still be used to test small quantities of samples at a batch level. Moreover, the ever-increasing use of handheld devices has made NIRS easily accessible. Summary: We aim to provide a summary of new research in basic spectroscopic research, integrating the improvements of spectral imaging methods and big-data analytics. Furthermore, low-cost and portable devices have been produced, enabling remote analysis and further expanding the scope of NIRS applications. Looking forward, we anticipate that continued advancements in this field will enable even wider applications of NIRS for online or at-line quality monitoring in diverse fields.

DOI： 10.1007/s40725-023-00203-3

Characteristics of Resonance Sound in a Circular Saw Enclosure Reviewed Open Access

Takeyama, K; Yokochi, H; Nishio, S; Tsuchikawa, S

BIORESOURCES Vol. 18 ( 4 ) page： 8473 - 8483 2023.11

Language：English Publishing type：Research paper (scientific journal) Publisher：BioResources

Several studies have been conducted to reduce the idling noise of circular saws because the sound level is extremely high and harms the environment. However, conventional noise suppression technology only controls the vibrations of the circular saw itself, whereas idling noise can be generated when the air inside the enclosure is resonant. In this study, the relationship between the rotational speeds of the circular saw blade and the frequencies of the resonance sound when the circular saw blade is running idle in an enclosure was examined. Additionally, the sound pressure modes and frequencies of the air in the enclosure were analyzed using the finite element method of acoustic analysis. The results showed that resonance sound was generated only when the circular saw blade was enclosed. The frequencies of the resonance sound generated by a circular saw blade made of acrylic plastic were the same as those generated by a steel saw blade. The resonance sound was generated regardless of the outer diameter of the circular saw blade. The peak resonant frequencies formed a step-like line during the analysis in which the rotational speed of the saw blade was steadily increased.

DOI： 10.15376/biores.18.4.8473-8483

Thermal behavior of heat-treated wood using two-dimensional correlation of near-infrared spectroscopy and differential scanning calorimetry Reviewed

Mahdiyanti, SH; Inagaki, T; Ridho, MR; Marsoem, SN; Tsuchikawa, S

WOOD SCIENCE AND TECHNOLOGY Vol. 57 ( 6 ) page： 1485 - 1506 2023.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Wood Science and Technology

Heat treatment of wood can decrease its heat capacity and thermal transitions, which are thermal behavior properties of wood. A calorimetric study that highlights the thermal behavior of the molecular mobility of materials is necessary to investigate the thermal degradation of wood. Furthermore, combining it with a nondestructive measurement technique would widen its scope of applicability, especially for wood in service or historical wood that cannot be altered or damaged by invasive methods. Neolamarckia cadamba (Roxb.) Bosser, also known as burflower-tree, a tropical fast-growing hardwood species that has become popular for light-construction works in the past decade, is treated at 90, 120, and 150 ℃ for a duration of 8 h to 3.5 months, scheduled logarithmically. Near-infrared spectroscopy and differential scanning calorimetry (DSC) were used to measure the chemical changes and thermal behavior of the wood before and after heat treatment. Two-dimensional correlation spectroscopy (2DCOS) analysis was then applied to assess the NIR second-derivative spectra and DSC thermograms. The results showed that 2DCOS analysis could assess NIR second-derivative spectra and DSC thermograms under careful observation, as DSC thermograms comprise both qualitative and quantitative information. It provides a new point of view in the non-destructive analysis of wood thermal degradation.

DOI： 10.1007/s00226-023-01506-1

Review of near infrared hyperspectral imaging applications related to wood and wood products Reviewed

Laurence Schimleck, Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

APPLIED SPECTROSCOPY REVIEWS Vol. 58 ( 9 ) page： 585 - 609 2023.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS INC

Hyperspectral imaging is a technique that combines spectroscopy and imaging. Originally utilized in the 1980's by the remote sensing community it is now utilized in a wide variety of applications. Spectral imaging was first used for the detection of compression wood in the late 1990's and since that time research focused on wood and wood products has steadily increased with a variety of applications reported. While there are several reviews of wood related research utilizing near infrared spectrometers a comprehensive summary of wood-hyperspectral imaging research is lacking. Near infrared hyperspectral imaging systems (NIR-HSI) typically have a wavelength range of 900-1700 nm, whereas short-wave infrared hyperspectral imaging (SWIR-HSI) systems range from 1000 to 2500 nm. We provide a detailed account of the various studies that have been published utilizing both camera types.

DOI： 10.1080/05704928.2022.2098759

Fit-free analysis of fluorescence lifetime imaging data using chemometrics approach for rapid and nondestructive wood species classification Reviewed

Validation study on light scattering changes in kiwifruit during postharvest storage using time-resolved transmittance spectroscopy Reviewed Open Access

Ma, T; Inagaki, T; Tsuchikawa, S

SCIENTIFIC REPORTS Vol. 13 ( 1 ) page： 16556 2023.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Scientific Reports

Visible and near-infrared spectroscopy has been well studied for characterizing the organic compounds in fruit and vegetables from pre-harvest to late harvest. However, due to the challenge of decoupling of optical properties, the relationship between the collected samples’ spectral data and their properties, especially their mechanical properties (e.g., firmness, hardness, and resilience) is hard to understand. This study developed a time-resolved transmittance spectroscopic method to validate the light scattering changing characteristics in kiwifruit during shelf-life and in cold storage conditions. The experimental results demonstrated that the reduced scattering coefficient (μs′) of 846 nm inside kiwifruit decreased steadily during postharvest storage and is more evident under shelf-life than in cold storage conditions. Moreover, the correlation between the μs′ and the storage time was confirmed to be much higher than that using the external color indexes measured using a conventional colorimeter. Furthermore, employing time-resolved profiles at this single wavelength, an efficacious mathematical model has been successfully formulated to classify the stages of kiwifruit softening, specifically early, mid-, and late stages. Notably, classification accuracies of 84% and 78% were achieved for the shelf-life and cold storage conditions, respectively.

DOI： 10.1038/s41598-023-43777-5

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Holzforschung Vol. 77 ( 9 ) page： 724 - 733 2023.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Walter de Gruyter GmbH

Abstract

Conventional fluorescence spectroscopy has been suggested as a valuable tool for classifying wood species rapidly and non-destructively. However, because it is challenging to conduct absolute emission intensity measurements, fluorescence analysis statistics are difficult to obtain. In this study, another dimension of fluorescence, that is, fluorescence lifetime, was further evaluated to address this issue. A time-resolved fluorescence spectroscopic measurement system was first designed, mainly using a streak camera, picosecond pulsed laser at 403 nm, and a spectroscope, to collect the fluorescence time-delay (FTD) profiles and steady-state fluorescence intensity (FI) spectra simultaneously from 15 wood species. For data analysis, principal component analysis was used to “compress” the mean-centered FTD and FI spectra. Then, support vector machine classification analysis was utilized to train the wood species classification model based on their principal component scores. To avoid overfitting, ten-fold cross-validation was used to train the calibration model using 70 % of the total samples, and the remaining 30 % hold-out validation was used to test its reproducibility. The cross-validation accuracies were 100 % (5 softwoods) and 96 % (10 hardwoods), with test-validation accuracies of 96 % and 89 %.

DOI： 10.1515/hf-2023-0017

Development of a sensitivity-enhanced chlorophyll fluorescence lifetime spectroscopic method for nondestructive monitoring of fruit ripening and postharvest decay Reviewed

Other Link： https://www.degruyter.com/document/doi/10.1515/hf-2023-0017/pdf

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

POSTHARVEST BIOLOGY AND TECHNOLOGY Vol. 198 2023.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

Nondestructive monitoring of the environmental changes around fluorescent molecules in postharvest fruit is highly informative for monitoring their ripening and early decay process. In this study, a time-resolved laser-induced fluorescence (TRLIF) spectroscopic system, including a streak camera, spectrometer, and 403 nm picosecond-pulsed laser, was first developed. Then, representative pigments in photosynthesis (chlorophyll a, chlorophyll b, and carotenoids liquid samples) were initially measured and studied to determine whether the developed TRLIF spectroscopic system could produce the characteristics of chlorophyll fluorescence decay traces. Finally, the same approach was tested to monitor the ripening and early decay processes of each three samples of avocado and strawberry. The overall findings demonstrated that the fluorescence lifetime (FLT) of the fruit samples declined steadily during the shelf-life storage. For the avocados samples, the average FLT loss at the wavelength range of 706-749 nm decreased by approximately 23 % and 31 % at 1 and 2 d under shelf-life storage, respectively. For the strawberry samples, the average FLT loss at the wavelength range of 631-706 nm decreased by approximately 22 %, 46 %, 68 %, and 73 % at 0.5, 1, 1.5, and 2 d under the same shelf-life storage condition. This study indicates that the developed TRLIF spectroscopic method is potentially robust and accurate for assessing the ripening and early decay process of various climacteric and non-climacteric fruit.

DOI： 10.1016/j.postharvbio.2022.112231

Visualization of Sugar Content Distribution of White Strawberry by Near-Infrared Hyperspectral Imaging Reviewed Open Access

Hayato Seki, Te Ma, Haruko Murakami, Satoru Tsuchikawa, Tetsuya Inagaki

Foods Vol. 12 ( 5 ) 2023.3

Language：English Publishing type：Research paper (scientific journal)

In this study, an approach to visualize the spatial distribution of sugar content in white strawberry fruit flesh using near-infrared hyperspectral imaging (NIR-HSI; 913–2166 nm) is developed. NIR-HSI data collected from 180 samples of “Tochigi iW1 go” white strawberries are investigated. In order to recognize the pixels corresponding to the flesh and achene on the surface of the strawberries, principal component analysis (PCA) and image processing are conducted after smoothing and standard normal variate (SNV) pretreatment of the data. Explanatory partial least squares regression (PLSR) analysis is performed to develop an appropriate model to predict Brix reference values. The PLSR model constructed from the raw spectra extracted from the flesh region of interest yields high prediction accuracy with an RMSEP and (Formula presented.) values of 0.576 and 0.841, respectively, and with a relatively low number of PLS factors. The Brix heatmap images and violin plots for each sample exhibit characteristics feature of sugar content distribution in the flesh of the strawberries. These findings offer insights into the feasibility of designing a noncontact system to monitor the quality of white strawberries.

DOI： 10.3390/foods12050931

Colour Modification of Wood by Dry Thermal Treatment between 90 oC and 200 oC Reviewed Open Access

Preklet E., Tolvaj L., Tsuchikawa S., Varga D.

Acta Silvatica et Lignaria Hungarica Vol. 19 ( 1 ) page： 9 - 20 2023

Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Silvatica et Lignaria Hungarica

The colour modification effect of dry thermal treatment was studied in black locust (Robinia pseudoacacia L.), poplar (Populus x euramericana cv. Pannonia), Scots pine (Pinus sylvestris L.), spruce (Picea abies Mill.) and larch (Larix decidua L.) species in the temperature range 90-200 °C. Colour data were presented and evaluated in the CIE L*a*b* coordinate system. All thermal treatments applied altered the wood colour throughout the entire cross section regardless of the treatment temperature. At lower temperatures, wood extractives played a decisive role in colour change. The degradation products of hemicelluloses were the major determinant of the change in lightness at 200°C. Redness change in percentage showed much greater alteration than the yellowness and the lightness change. Spruce presented the greatest chromaticity coordinate (a* and b*) alteration among the investigated species. Changes in redness and yellowness followed the Arrhenius law during the investigated dry thermal treatments confirming that the temperature dependence of these colour parameters is exponential for wood material.

DOI： 10.37045/aslh-2023-0001

Experimental study and three-dimensional modeling of moisture transport in wood by means of near-infrared hyperspectral imaging coupled with a heat and mass transfer simulation method Reviewed

Te Ma, Genki Morita, Tetsuya Inagaki, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 76 ( 8 ) page： 699 - 710 2022.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Substantial efforts have been undertaken for visualizing and simulating the characteristics of water movement in wood. However, three-dimensional (3D) thermo-hygric simulations still pose challenges, not only because wood has a heterogeneous microstructure that results in complex computational models but also because there is a lack of proper experimental techniques to support and validate the model constructions. In this study, the moisture distribution in wood during the water adsorption and desorption processes was first visualized using a near-infrared hyperspectral imaging (NIR-HSI) method that has high resolution, sensibility, and stability. Then, based on the moisture visualization results, the main parameters of a mass transfer simulation code were varied. The visualization and simulation results were confirmed to match well with the main characteristics; e.g., drying speed was slower in the wood parts with higher densities. Additionally, there was a relatively large gradient over the surface layer of the wood samples as the drying progressed, whereas this was not an obvious feature in the water adsorption process. Hence, this study proposes that the NIR-HSI method can be combined with thermo-hygric and 3D simulation model construction. Such an approach provides the basis for optimizing drying conditions and providing high-quality wood products.

DOI： 10.1515/hf-2021-0203

Cognitive spectroscopy for the classification of rice varieties: A comparison of machine learning and deep learning approaches in analysing long-wave near-infrared hyperspectral images of brown and milled samples Reviewed International coauthorship Open Access

Onmankhong J, Ma T, Inagaki T, Sirisomboon P, Tsuchikawa S

Infrared Physics and Technology Vol. 123 page： 104100 - 104100 2022.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

Rapid and non-destructive detection of genuine Thai Jasmine rice (Khao Dawk Mali 105 (KDML105)) from Pathum Thani1 (PTT1) and Phitsanulok2 (PSL2) under either milled or brown conditions is required to disrupt fraudulent. This study aimed to resolve this real issue using long-wave near infrared hyperspectral imaging (NIRHSI) coupled with machine learning and deep learning approaches. The best classification accuracy for the milled rice was achieved using the spectral imaging-based analysis on the NIR-HSI data with selected wavelength, approximately 95% for the test set either by convolutional neural network or support vector machine (SVM), whereas for the brown rice, the SVM model based on the averaged NIR spectra could achieve the best classification accuracy of 95.4%. It suggests the chemical component difference and its spatial distribution in the milled rice could contribute higher classification accuracy. Additionally, the surface bran effects of brown rice could be reduced by using averaged spectral data coupled with the SVM method.

DOI： 10.1016/j.infrared.2022.104100

Comparative Performance of NIR-Hyperspectral Imaging Systems Invited Reviewed International coauthorship

Ma Te, Schimleck Laurence, Dahlen Joseph, Yoon Seung-Chul, Inagaki Tetsuya, Tsuchikawa Satoru, Sandak Anna, Sandak Jakub

Foundations 2022.6

Comparative Performance of NIR-Hyperspectral Imaging Systems Invited Reviewed International coauthorship

Ma Te, Schimleck Laurence, Dahlen Joseph, Yoon Seung-Chul, Inagaki Tetsuya, Tsuchikawa Satoru, Sandak Anna, Sandak Jakub

Foundations 2022.6

Production of Nanocellulose Film from Abaca Fibers Reviewed International coauthorship Open Access

Anniver Ryan Lapuz, Satoru Tsuchikawa, Tetsuya Inagaki, Te Ma, Veronica Migo

CRYSTALS Vol. 12 ( 5 ) 2022.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：MDPI

Abaca fibers were subjected to a TEMPO mediated oxidation to extract nanocellulose on a 500 L capacity locally fabricated reactor. A yield of 46.7% white gel material with 2.23% solid content was obtained from an overnight reaction. Transmission electron microscopy scan of the white gel material confirms the production of relatively short highly individualized cellulose nanofibril (CNF) as the diameter of abaca fiber was reduced from 16.28 mu m to 3.12 nm with fiber length in the range of 100 nm to 200 nm. Nanocellulose film was prepared using air drying (CNF-VC) and vacuum oven drying (CNF-OD). The effect of CNF concentration on the physical, morphological, thermal and mechanical properties were evaluated. FTIR spectra showed cellulose I spectra between abaca fiber with both the CNF-VC film and CNF-OD film with two distinct peaks at 1620 cm(-1) and 1720 cm(-1) attributed to the carboxyl group resulting from the TEMPO oxidation. In addition, the carboxyl group decreases in thermal stability of cellulose. Moreover, the XRD scan showed a decrease in crystallinity index of CNF films compared to abaca fibers. CNF-VC film showed the highest tensile strength at 0.4% concentration with 88.30 MPa, while a 89.72 MPa was observed for CNF-OD film at 0.8% concentration.

DOI： 10.3390/cryst12050601

Terahertz time-domain spectroscopy as a novel tool for crystallographic analysis in cellulose: cellulose I to cellulose II, tracing the structural changes under chemical treatment Reviewed Open Access

Wang Han, Kataoka Hiroki, Tsuchikawa Satoru, Inagaki Tetsuya

CELLULOSE Vol. 29 ( 6 ) page： 3143 - 3151 2022.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Terahertz time-domain spectroscopy (THz-TDS) has expanded possibilities in cellulose crystallography research, as THz radiation detects most intermolecular vibrations and responds to the phonons of crystalline lattices. In this study, we traced the transformation of the cellulose crystalline lattice from cellulose I to cellulose II by THz-TDS and X-ray powder diffraction. Cellulose II was obtained by treating cellulose I with NaOH of different concentrations (0 wt%-20 wt%, at 2 wt% intervals). The THz absorption coefficient spectra of cellulose II showed three characteristic peaks (at 1.32 THz, 1.76 THz, and 2.77 THz). The THz absorption coefficient spectra of cellulose II treated with 20-wt% NaOH and cellulose I without NaOH treatment were fitted by a seventh-order Fourier series. Thus, the THz absorption coefficient spectra of samples treated with NaOH of other concentrations could be considered a combination of these two fitted profiles of cellulose I and cellulose II, multiplied by different coefficients. Furthermore, the coefficients could reflect the relative contents of cellulose I and cellulose II in the samples.

DOI： 10.1007/s10570-022-04493-x

Application of near-infrared spectroscopy to agriculture and forestry. Reviewed

Tsuchikawa S, Ma T, Inagaki T

Analytical sciences : the international journal of the Japan Society for Analytical Chemistry Vol. 38 ( 4 ) page： 635 - 642 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGERNATURE

Depending on the uniformity of the quality attribute within agricultural products, there is often a need to develop non-destructive and efficient evaluation methods to assure their qualities. Near-infrared spectroscopy (NIRS) is a well-suited method to characterize organic compounds, particularly when coupled with multivariate analysis methods. This review article introduces scientific and technical reports using the NIRS to evaluate food, agriculture, and forest products. Overall, basic spectroscopic research is continuously progressing; indeed, in combination with big-data information technology and spectral imaging techniques, material analysis is improving to maximize performance. Portable and low-cost devices have also been designed and produced, enabling remote analysis. Future advancements are expected to result in its applications in even more fields for online or at-line quality monitoring.

DOI： 10.1007/s44211-022-00106-6

Rapid and nondestructive prediction of firmness, soluble solids content, and pH in kiwifruit using Vis–NIR spatially resolved spectroscopy Reviewed International coauthorship Open Access

Ma T, Zhao J, Inagaki T, Su Y, Tsuchikawa S

Postharvest Biology and Technology Vol. 186 2022.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ELSEVIER

This paper reports an evaluation of firmness, soluble solids content (SSC), and acidity (pH) in kiwifruit using a newly designed visible-near-infrared (Vis-NIR) spatially resolved spectroscopic (SRS) system. The system mainly comprises a cost-effective Vis-NIR hyperspectral imaging camera, a halogen light source, and 36 light-receiving silica fibers which were divided into six groups (1, 2, 3, 4, 5, and 10 mm away from the light illumination) used to collect diffusely reflected light from sample surface. During the experiment, time-resolved spectroscopy (TRS) was used to validate the light scattering characteristics at a single wavelength of 846 nm by transmission measurement, which differed from the reflectance measurement of the SRS system. The TRS results show that firmer kiwifruits tended to have a lower transmitted light intensity and a higher full width at half maximum value. The SRS results indicate that the reflected light intensity decreased more with an increased distance from the illumination spot in firmer kiwifruits. The results of the two methods supported the same view, i.e., firmer kiwifruit indicated higher degrees of light scattering inside. Following on, the calibration models for kiwifruit properties were constructed using the SRS data coupled with partial least squares regression analysis. Finally, the prediction accuracies were benchmarked against standard diffuse reflectance spectroscopy using one fiber group position of the same SRS system. The overall results showed the benefits of using the SRS system to predict fruit firmness by enhancing light scattering effects and predicting the SSC required for reducing such effects

DOI： 10.1016/j.postharvbio.2022.111841

Moisture transport dynamics in wood during drying studied by long-wave near-infrared hyperspectral imaging Reviewed

Ma Te, Morita Genki, Inagaki Tetsuya, Tsuchikawa Satoru

CELLULOSE Vol. 29 ( 1 ) page： 133 - 145 2022.1

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The complexities of wood microstructure cause difficulties in understanding water movement characteristics during drying. Here, the water transport dynamics in softwood (Japanese cypress) with different sample lengths (30 mm, 60 mm, and 90 mm) and various drying temperatures (30 degrees C, 60 degrees C, and 90 degrees C) were studied using a rapid and high-resolution moisture content (MC) mapping method based on long-wave near-infrared hyperspectral imaging (NIR-HSI). The observations of this study are as follows: slow drying at approximately 30 degrees C, the area near the subsurface of the wood samples tends to have higher MC than the central parts during drying, especially in the case of longer wood samples. For drying at higher temperatures, strongly bonded water appeared at the surface areas much earlier, which could easily cause sample deformation and cracking. Overall, the experimental results suggest the capillary effects could play a major role at the first stage of slow drying at fiber level; then, the transfers between bound and free water could play a significant power source in the second drying stage. It is expected that this study will be of help in providing a basis to study and simulate the drying characteristics of cellular and hydrophilic materials.

DOI： 10.1007/s10570-021-04290-y

Near-infrared spectroscopy and hyperspectral imaging can aid in the prediction and mapping of polyploid acacia hybrid wood properties in tree improvement programs Reviewed

Dang Duc Viet, Ma Te, Inagaki Tetsuya, Nguyen Tu Kim, Tsuchikawa Satoru

HOLZFORSCHUNG Vol. 75 ( 12 ) page： 1067 - 1080 2021.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Acacia, including Acacia hybrids, are some of the most important species grown as part of the Viet-namese wood industry. Rapid methods to identify the variations in the wood properties of Acacia hybrids how -ever, are a currently lacking and creating limits for their breeding programs. In this study, nine Acacia hybrid clones, including those that were diploid, triploid, and tetraploid were evaluated using near-infrared spectros-copy (NIR) and hyperspectral imaging (HSI). The standard normal variate (SNV) and second derivative (SP2D) were applied to compare the performances of NIR and HSI using partial least square regression. The HSI images were ac-quired at wavelengths from 1033 to 2230 nm and the SNV and SP2D described the variations in the wood properties. The NIR predicted the wood physical properties better than HSI, while they provided similar predictions for the mechanical properties. The mapping results showed low densities around the pith area and high densities near the bark. They also revealed that the air-dry moisture content changed at different positions within a disk and was dependent on its position within the tree. Overall, NIR and HSI were found to be potential wood property prediction tools, suitable for use in tree improvement programs.

DOI： 10.1515/hf-2021-0024

Measuring the tensile strain of wood by visible and near-infrared spatially resolved spectroscopy Reviewed Open Access

Te Ma, Tetsuya Inagaki, Masato Yoshida, Mayumi Ichino, Satoru Tsuchikawa

Cellulose Vol. 28 ( 17 ) page： 10787 - 10801 2021.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Strain measurement is critical for wood quality evaluation. Using conventional strain gauges constantly is high cost, also challenging to measure precious wood materials due to the use of strong adhesive. This study demonstrates the correlation between the light scattering degrees inside the wood during tension testing and their macroscopic strain values. A multifiber-based visible-near-infrared (Vis-NIR) spatially resolved spectroscopy (SRS) system was designed to rapidly and conveniently acquire such light scattering changes. For the preliminary experiment, samples with different thicknesses, from 2 to 5 mm, were measured to evaluate the influence of sample thickness. The differences in Vis-NIR SRS spectral data diminished with an increase in sample thickness, suggesting that the SRS method can successfully measure the wood samples' whole strain (i.e., surface and inside). Then, for the primary experiment, 18 wood samples were each prepared with approximately the same sample thickness of 2 mm and 5 mm to construct strain calibration models, respectively. The prediction accuracy of the 2-mm samples was characterized by a determination coefficient (R-2) of 0.81 with a root mean squared error (RMSE) of 343.54 mu epsilon for leave-one-out cross-validation; for test validation, the validation accuracy was characterized by an R-2 of 0.76 and an RMSE of 395.35 mu epsilon. For the validation accuracy of the 5-mm samples, R-val(2) was 0.69 with 440.78 mu epsilon RMSEval. Overall, the presented calibration results of the SRS approach were confirmed to be superior to the standard diffuse reflectance spectroscopy.

DOI： 10.1007/s10570-021-04239-1

Other Link： https://link.springer.com/article/10.1007/s10570-021-04239-1/fulltext.html

Parameter Optimization of Vibrating and Comb-Brushing Harvesting of Lycium barbarum L. Based on FEM and RSM Reviewed Open Access

Jian Zhao, Te Ma, Tetsuya Inagaki, Yun Chen, Guangrui Hu, Zhiwei Wang, Qingyu Chen, Zening Gao, Jianguo Zhou, Miaohai Wang, Satoru Tsuchikawa, Jun Chen

Horticulturae Vol. 7 ( 9 ) page： 286 - 286 2021.9

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

The current mechanical harvesting methods of Lycium barbarum L. are labor intensive and cause too much damage, but vibrating and comb-brushing harvesting can increase the efficiency while minimizing the damage. However, optimizing the main factors and their parameter values of vibrating and comb-brushing harvesting is challenging. To achieve the high-efficiency and low-damage harvesting of L. barbarum, firstly, the mechanical models of the materials used in the experiments were established based on the physical tests. Then, the vibrating and comb-brushing harvesting simulations were conducted based on FEM to acquire the ranges of the parameter values. The effects of the rotating speed, material, and amplitude on the harvesting rate of ripe fruit and harvesting rate of unripe fruit, as well as the damage rate of ripe fruit were determined based on RSM. Finally, the optimized parameters were obtained and verified using the field experiments. The field experiments showed that the harvesting rate of ripe fruit was 85.8%, the harvesting rate of unripe fruit was 10.5%, and the damage rate of ripe fruit was 9.7%. The findings provided the optimal parameter values, which were a design basis for the vibrating and comb-brushing harvesters of L. barbarum.

DOI： 10.3390/horticulturae7090286

Terahertz time-domain spectroscopy as a novel tool for crystallographic analysis in cellulose: the potentiality of being a new standard for evaluating crystallinity Reviewed

Using near-infrared spectroscopy to determine moisture content, gel strength, and viscosity of gelatin Reviewed International coauthorship

Simon Duthen, Cecile Levasseur-Garcia, Didier Kleiber, Frédéric Violleau, Carlos Vaca-Garcia, Satoru Tsuchikawa, Christine Delgado Raynaud, Jean Daydé

Food Hydrocolloids Vol. 115 page： 106627 - 106627 2021.6

Han Wang, Satoru Tsuchikawa, Tetsuya Inagaki

Cellulose Vol. 28 ( 9 ) page： 5293 - 5304 2021.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Given that terahertz (THz) radiation responds to intermolecular forces such as hydrogen bonds, THz time-domain spectroscopy (THz-TDS) has expanded possibilities in cellulose research. In this study, THz-TDS was used to investigate the crystallinity of three types of cellulose-based materials. Microcrystalline cellulose (MCC) and wood were ball milled at different times, and pseudo-wood was a mixture of MCC and lignin of different mass fractions. All the samples showed peaks at 3.04 THz in the THz mass absorption coefficient spectra. Further, the spectra from 2.79 THz to 3.32 THz were cut out and detrended by subtraction from a baseline. The integrated intensity of the detrended spectra showed a correlation with the mass fraction of lignin of the pseudo-wood samples, and ball milling time of the MCC and wood samples. The correlation was similar with the crystallinity index calculated from X-ray powder diffraction. Moreover, the original wood sample without ball milling had an integrated intensity that was about 30% that of the original MCC sample, matching with the cellulose concentration of the wood (about 30% to 40%). We normalized the integrated intensity of 2.79 THz to 3.32 THz into 1 to 0 by a min-max algorithm and proposed a new "index" for evaluating crystallinity.

DOI： 10.1007/s10570-021-03902-x

Other Link： https://link.springer.com/article/10.1007/s10570-021-03902-x/fulltext.html

Modal Analysis and Experiment of a Lycium barbarum L. Shrub for Efficient Vibration Harvesting of Fruit Reviewed Open Access

Jian Zhao, Satoru Tsuchikawa, Te Ma, Guangrui Hu, Yun Chen, Zhiwei Wang, Qingyu Chen, Zening Gao, Jun Chen

Agriculture Vol. 11 ( 6 ) page： 519 - 519 2021.6

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

The most common harvesting method of Lycium barbarum L. (L. barbarum) is manual harvesting, resulting in low efficiency and high cost. Meanwhile, the efficiency of vibration harvesting, which is considered an efficient mechanical harvesting method, can be significantly improved if the optimized resonance frequency of the shrub can be obtained. To vibration harvest fruit efficiently, a 3D model of the shrub was established based on measurements of the shape parameters, and material mechanics models of the branches were established based on physical tests. The modal analysis of the shrub based on finite element method (FEM) simulation was performed to obtain the range of resonance frequency, and the modal experiment of the shrub using acceleration sensors and an impact hammer was conducted to obtain the accurate resonance frequency. Based on the results of the modal analysis and experiment, the optimized resonance frequency was determined to be 2 Hz. The field experiment showed that the fruit fell off when the branches were vibrated at this frequency. The results provide the design basis for the efficient vibration harvesting of L. barbarum.

DOI： 10.3390/agriculture11060519

Finite Element Method Simulations and Experiments of Detachments of Lycium barbarum L. Reviewed Open Access

Jian Zhao, Te Ma, Tetsuya Inagaki, Qingyu Chen, Zening Gao, Lijuan Sun, Haoxuan Cai, Chao Chen, Chuanlin Li, Shixia Zhang, Satoru Tsuchikawa, Jun Chen

Forests Vol. 12 ( 6 ) page： 699 - 699 2021.6

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

When harvesting Lycium barbarum L., excess amounts of detachments of the half-ripe fruit, unripe fruit, flowers, and leaves significantly affect the yield and adversely affect the subsequent processing, such as drying and grading. Finite element method (FEM) simulations and experiments of detachments were performed to harvest more ripe fruit and less half-ripe fruit, unripe fruit, flowers, and leaves. Three-dimensional (3D) models of the ripe fruit, half-ripe fruit, unripe fruit, flowers, leaves, fruit calyxes (flower calyx), fruit stems (flower stem), and branches were constructed using a 3D scanner, and material mechanics models of the above parts were established based on physical tests with universal testing machines. Detachment simulations and experiments of the ripe fruit, half-ripe fruit, unripe fruit, flowers, and leaves were performed to determine the detachment mechanisms and sequences. The detachment forces of each set of two parts were obtained. The field experiments showed that the detachment force between the fruit and calyx of ripe fruit was the lowest value of these forces, and only the ripe fruit was the first to detach from the calyx when harvesting. The results provided data support on the mechanics properties of wood and the optimization basis for the harvesting method of L. barbarum.

DOI： 10.3390/f12060699

Demonstration of the applicability of visible and near-infrared spatially resolved spectroscopy for rapid and nondestructive wood classification Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Holzforschung Vol. 75 ( 5 ) page： 419 - 427 2021.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Walter de Gruyter GmbH

<title>Abstract</title>
Although visible and near-infrared (Vis-NIR) spectroscopy can rapidly and nondestructively identify wood species, the conventional spectrometer approach relies on the aggregate light absorption due to the chemical composition of wood and light scattering originating from the physical structure of wood. Hence, much of the work in this area is still limited to further spectral pretreatments, such as baseline correction and standard normal variate to reduce the light scattering effects. However, it should be emphasized that the light scattering rather than absorption in wood is dominant, and this must be effectively utilized to achieve highly accurate and robust wood classification. Here a novel method based on spatially resolved diffuse reflectance (wavelength range: 600–1000 nm) was demonstrated to classify 15 kinds of wood. A portable Vis-NIR spectral measurement system was designed according to previous simulations and experimental results. To simplify spectral data analysis (i.e., against overfitting), support vector machine (SVM) model was constructed for wood sample classification using principal component analysis (PCA) scores. The classification accuracies of 98.6% for five-fold cross-validation and 91.2% for test set validation were achieved. This study offers enhanced classification accuracy and robustness over other conventional nondestructive approaches for such various kinds of wood and sheds light on utilizing visible and short-wave NIR light scattering for wood classification.

DOI： 10.1515/hf-2020-0074

Other Link： https://www.degruyter.com/document/doi/10.1515/hf-2020-0074/xml

Characteristics of self-excited alternate-tooth vibration of circular saw blade Reviewed Open Access

Ken Takeyama, Hideyuki Yokochi, Satoru Nishio, Satoru Tsuchikawa

BioResources Vol. 16 ( 2 ) page： 3840 - 3850 2021.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：BioResources

In recent years, circular saw blades with thinner kerfs have been in high demand for improvement of the production yield of wood-based materials and the reduction of sawdust. In the case of ripping of solid wood, the number of teeth of a circular saw blade is normally set to 40 or 50, with a diameter of 305 mm, which allows less cutting resistance and smooth exhausting of sawdust. However, at certain rotational speeds, self-excited alternate-tooth vibration can easily occur in circular saw blades with such thin kerfs and so few teeth. Therefore, the cutting surface quality tends to be worse. In this study, the mechanism of this self-excited alternate-tooth vibration was clarified. The vibration mode and frequency were predicted by the finite element method. In addition, a circular saw blade with a body thickness 1.5 mm and 50 teeth was employed for wood-cutting experiments. The rotational speed range of the self-excited alternate-tooth vibration modes and their frequencies were investigated. When a double of the tooth passage frequency was slightly higher than the frequencies of the alternate-tooth vibration modes, an alternate-tooth vibration of the regenerative chatter type was excited, owing to the forces on the sides of the tooth.

DOI： 10.15376/biores.16.2.3840-3850

Non-destructive and fast method of mapping the distribution of the soluble solids content and pH in kiwifruit using object rotation near-infrared hyperspectral imaging approach Reviewed International coauthorship

Te Ma, Yu Xia, Tetsuya Inagaki, Satoru Tsuchikawa

Postharvest Biology and Technology Vol. 174 2021.4

Language：English Publishing type：Research paper (scientific journal)

© 2020 Elsevier B.V. This work aimed to offer a non-destructive and fast approach to visualizing the soluble solids content (SSC) and acidity (pH) of the whole kiwifruit. Most of the visible-near-infrared spectral imaging techniques used in postharvest fruit and vegetables assessment exhibit issues related to the identification of the quality spatial distribution within intact samples, mainly due to sampling surface curvature effects. Here, a push-broom-type NIR hyperspectral imaging camera and a sample rotation stage were combined to scan entire kiwifruit surfaces. Then, key wavelengths in the range of 1002–2300 nm were extracted for constructing SSC and pH calibration models by partial least squares regression analysis. The resulting SSC prediction accuracy was sufficiently high: the coefficient of determination (R2cv) and the root mean square error (RMSEcv) of cross-validation set were 0.74 and 0.7 %, respectively. For pH, the R2cv and RMSEcv were 0.64 and 0.14, respectively. Finally, the SSC and pH 360˚mapping results surpassed earlier works in this area that they showed a distinct spatial distribution within each intact sample. It was concluded that the proposed object rotation hyperspectral imaging approach is promising for the non-destructive prediction mapping of SSC and pH in kiwifruit or other cylindrical-shaped samples.

DOI： 10.1016/j.postharvbio.2020.111440

Rapid and nondestructive evaluation of hygroscopic behavior changes of thermally modified softwood and hardwood samples using near-infrared hyperspectral imaging (NIR-HSI) Reviewed International coauthorship

Te Ma, Laurence Schimleck, Tetsuya Inagaki, Satoru Tsuchikawa

Holzforschung Vol. 75 ( 4 ) page： 345 - 357 2021.4

Language：English Publishing type：Research paper (scientific journal)

© 2020 Walter de Gruyter GmbH, Berlin/Boston 2020. The objective of this work was to provide a rapid and nondestructive imaging method for evaluating the hygroscopic behavior of thermally modified lignocellulosic materials (softwood and hardwood). The difference in the hygroscopic behavior was explained by moisture content (MC) mapping results and molecular association characteristics of absorbed water (i.e. weakly, moderately, and strongly hydrogen-bonded water molecules) with wood at various relative humidities (RH). To achieve this goal, near-infrared (NIR) spectral images in the wavelength range 1816-2130 nm (covering the combination of stretching and deformation vibrations for OH) were used to visualize MC distributions over the surface of Japanese cedar and European beech samples which had been thermally treated at different temperatures. A curve fitting method was utilized to explore changes in water-wood structure characteristics based on shifts to longer wavelength in spectral signals caused by increasing MC. The curve fitting results support the recent nuclear magnetic resonance (NMR) studies that different bound water stabilities may pool in different compartments of the wood cell wall. Furthermore, water was firmly bound to wood at low RHs and H-bonds gained mobility as the number of absorbed molecules increased. It is concluded that NIR hyperspectral imaging also has the potential to be a complementary methodology for studying the transient changes of wood-water interactions before equilibrium.

DOI： 10.1515/hf-2019-0298

Rapid and nondestructive evaluation of soluble solids content (SSC) and firmness in apple using Vis–NIR spatially resolved spectroscopy Reviewed

Te Ma, Yu Xia, Tetsuya Inagaki, Satoru Tsuchikawa

Postharvest Biology and Technology Vol. 173 2021.3

Language：English Publishing type：Research paper (scientific journal)

© 2020 Elsevier B.V. Visible–near infrared (Vis–NIR) spectroscopy is a rapid and nondestructive method used to characterize organic compounds in postharvest fruit and vegetable assessment. However, developing robust calibration models is a challenge as conventional spectrometers collect only the cumulative effects of light absorption and scattering. In this study, a multifiber-based Vis–NIR spatially resolved spectra measurement system was designed for simultaneous evaluation of soluble solid content (SSC) and firmness in apple. Thirty silica fibers separated into five groups at 1, 2, 3, 4, and 5 mm away from the light illumination point and connected to a cost-effective Vis–NIR hyperspectral imaging camera were used to acquire spectral data with an improved signal-to-noise ratio (S/N) by a two-step signal averaging process (i.e., 30 camera pixels per fiber and six optical fibers per group). Reflectance ratio spectra were then calculated by dividing the diffusely reflected light intensity detected at distance d +△ by that detected at distance d to realize a light reference-free approach. Finally, the useful explanatory variables were selected by competitive adaptive reweighted sampling (CARS) to construct individual calibration models for various regions. The coefficients of determination (Rcal2) and the root mean square errors (RMSEcal) of the best-performing calibration models were approximately 0.97 and 0.20 % for SSC and 0.96 and 0.37 N for firmness, respectively. Furthermore, the predicted results were 0.92 and 0.35 % for SSC and 0.87 and 0.71 N for firmness. Our method offers low-cost and portable detection of SSC and firmness for postharvest fruit evaluation.

DOI： 10.1016/j.postharvbio.2020.111417

Rapid and nondestructive evaluation of soluble solids content (SSC) and firmness in apple using Vis-NIR spatially resolved spectroscopy Reviewed

Ma, T; Xia, Y; Inagaki, T; Tsuchikawa, S

POSTHARVEST BIOLOGY AND TECHNOLOGY Vol. 173 2021.3

Photodegradation Properties of Earlywood and Latewood Spruce Timber Surfaces Reviewed International coauthorship Open Access

Preklet E., Tolvaj L., Tsuchikawa S., Varga D.

Acta Silvatica et Lignaria Hungarica Vol. 17 ( 1 ) page： 9 - 20 2021

Terahertz time-domain spectroscopy as a novel tool for crystallographic analysis in cellulose Reviewed

Wang Han, Horikawa Yoshiki, Tsuchikawa Satoru, Inagaki Tetsuya

CELLULOSE Vol. 27 ( 17 ) page： 9767 - 9777 2020.11

Rapid and non-destructive seed viability prediction using near-infrared hyperspectral imaging coupled with a deep learning approach Reviewed

Te Ma, Satoru Tsuchikawa, Tetsuya Inagaki

Computers and Electronics in Agriculture Vol. 177 2020.10

Language：English Publishing type：Research paper (scientific journal)

© 2020 Elsevier B.V. Seeds are the basis of the agricultural food industry, greater insights into seed viability before sowing could improve storage management and field performance. In the present study, we aimed to address this issue by using highly cost-efficient near-infrared hyperspectral imaging (NIR-HSI) and a convolutional neural network (CNN) deep learning approach. An NIR-HSI camera was used because it can recognize both molecular vibration information (i.e. chemical component differences) and its spatial distribution in each seed sample; this camera is much more informative than a regular RGB digital camera. Using this technology, the emphasis of this study was firstly to provide a methodology for enhancing the interpretability of viable and non-viable seeds via principal component analysis (PCA) and support vector machine (SVM) viability classification analysis of NIR-HSI data. A CNN was then constructed to“cognize” the differences in viable and non-inviable seeds and classify them automatically. Experimental results indicate that the methodology produces a ~90% classification accuracy for both a five-fold cross-validation set and a test set of naturally aged Japanese mustard spinach seeds. Therefore, this study provides a new strategy for effective and practical seed viability prediction.

DOI： 10.1016/j.compag.2020.105683

Physical and mechanical properties of fast growing polyploid acacia hybrids (A. auriculiformis x A. mangium) from Vietnam Reviewed International coauthorship Open Access

Dang Duc Viet, Te Ma, Tetsuya Inagaki, Nguyen Tu Kim, Nghiem Quynh Chi, Satoru Tsuchikawa

Forests Vol. 11 ( 7 ) 2020.7

Language：English Publishing type：Research paper (scientific journal)

© 2020 by the authors. Acacia plants are globally important resources in the wood industry, but particularly in Southeast Asian countries. In the present study, we compared the physical and mechanical properties of polyploid Acacia (3x and 4x) clones with those of diploid (2x) clones grown in Vietnam. We randomly selected 29 trees aged 3.8 years from different taxa for investigation. BV10 and BV16 clones represented the diploid controls; X101 and X102 were the triploid clones; and AA-4x, AM-4x, and AH-4x represented neo-tetraploid families of Acacia auriculiformis, Acacia mangium, and their hybrid clones. The following metrics were measured in each plant: stem height levels, basic density, air-dry equilibrium moisture content, modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and Young's modulus. We found that the equilibrium moisture content significantly differed among clones, and basic density varied from pith-to-bark and in an axial direction. In addition, the basic density of AA-4x was significantly higher than that of the control clones. Furthermore, the MOR of AM-4x was considerably lower than the control clones, whereas the MOE of X101 was significantly higher than the control values. The compression strength of AM-4x was significantly lower than that of the control clones, but AH-4x had a significantly higher Young's modulus. Our results suggest that polyploid Acacia hybrids have the potential to be alternative species for providing wood with improved properties to the forestry sector of Vietnam. Furthermore, the significant differences among the clones indicate that opportunities exist for selection and the improvement of wood quality via selective breeding for specific properties.

DOI： 10.3390/f11070717

Rapidly visualizing the dynamic state of free, weakly, and strongly hydrogen-bonded water with lignocellulosic material during drying by near-infrared hyperspectral imaging Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Cellulose Vol. 27 ( 9 ) page： 4857 - 4869 2020.6

Language：English Publishing type：Research paper (scientific journal)

© 2020, Springer Nature B.V. Real-time monitoring of the dynamic state of water molecular structure in lignocellulosic material is challenging, but important for both theoretical studies and industrial applications. In the present study, three typical wood samples which have a fundamental difference in the anatomical structure were scanned in the near-infrared spectral range, and images were acquired from wavelengths of 1002–1847 nm during drying. Then, partial least squares regression was used to determine the water content by mass, and principal component analysis was utilized to characterize the variance of NIR difference spectral data between 1340 and 1610 nm after baseline correlation for showing the distribution changing from free water to bound water during air drying. It was clarified that the PC1 loading mainly correlates with simple water content by mass, whereas the PC2 loading contains information about water–wood hydrogen structure interactions. The three loading curve peaks of PC2 could be correlated with free, weakly bound, and strongly bound water based on longer wavelength shifting. Finally, PC1 and PC2 scores were comprehensively applied to show the distribution changing from free water to bound water in each wood sample with a 62.5 μm/pixel high spatial resolution.

DOI： 10.1007/s10570-020-03117-6

Simultaneous detection of density, moisture content and fiber direction of wood by THz time-domain spectroscopy Reviewed Open Access

Kashima Moe, Tsuchikawa Satoru, Inagakr Tetsuya

JOURNAL OF WOOD SCIENCE Vol. 66 ( 1 ) 2020.4

Steaming-caused chemical changes of sugi (Cryptomeria japonica) wood monitored by NIR spectroscopy Reviewed Open Access

Mahdiyanti S.H., Tsuchikawa S., Mitsui K., Tolvaj L.

Asian Journal of Forestry Vol. 4 ( 1 ) page： 6 - 9 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：Asian Journal of Forestry

Mahdiyanti SH, Tsuchikawa S, Mitsui K, Tolvaj L. 2020. Steaming-caused chemical changes of sugi (Cryptomeria japonica) wood monitored by NIR spectroscopy. Asian J For 4: 6-9. Steaming is a common method to change the color of wood to enhance attractiveness. This study aimed to investigate time-dependence of chemical changes of sugi (Cryptomeria japonica D. Don) wood steamed with temperature of 90 and 110°C and monitored up to 20 days using NIR spectroscopy. The difference spectrum method was applied to find the absorption increases and decreases. Before the subtraction, the spectra were normalized to one unit at 1739 nm to eliminate the parallel shift of the spectra. The results showed that steam-induced chemical changes in the wavelength range of 1300-2100 nm were related to the absorption of water and the absorption of extractives, especially phenolic contents. These chemical changes were suspected to be strongly related to color changes in steamed wood. Longer duration of steaming caused phenolic compounds to change into similar contents in all wood tissues, which cause their color to change more uniformly. Steaming caused a water bounding capacity loss of the cell wall. This change was much faster at 110°C than at 90°C.

DOI： 10.13057/asianjfor/r040102

Analysis of wood thermal degradation using 2D correlation of near infrared and visible-light spectroscopy Reviewed

Cognitive spectroscopy for wood species identification: near infrared hyperspectral imaging combined with convolutional neural networks.

Kanayama H, Ma T, Tsuchikawa S, Inagaki T

The Analyst Vol. 144 ( 21 ) page： 6438 - 6446 2019.11

Mahdiyanti Siti Hanifah, Inagaki Tetsuya, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 27 ( 5 ) page： 354 - 369 2019.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

Wood changes its properties, especially color, as a result of thermal degradation. In this study, change in wood properties due to thermal degradation have been studied using the nondestructive test methods of near infrared spectroscopy, CIELAB color measurement, visible-light spectroscopy, and Arrhenius time-temperature superposition. Arrhenius time-temperature superposition allowed analysis of near infrared and visible-light spectra, and color parameters to predict thermal degradation and color change of wood at 120-180celcius for 6 min to nine months duration. Two-dimensional correlation spectroscopy for the complementary analysis of near infrared and visible-light spectroscopy was applied to investigate chemical changes during wood thermal degradation that cause the observed color change. Visible-light spectroscopy with CIELAB color measurement was used to obtain information on color changes, and near infrared spectroscopy was applied in the measurement of chemical changes during thermal degradation. Changes in spectral intensities in 2D correlation spectroscopy indicated that different chemical components are responsible for color change during heat treatment and accelerated aging of wood. With dry-thermal treatment, the hemicellulose content decreased following a color change, whereas cellulose and lignin/extractives decreased with hygro-thermal treatment.

DOI： 10.1177/0967033519863878

Three-dimensional grain angle measurement of softwood (Hinoki cypress) using near infrared spatially and spectrally resolved imaging (NIR-SSRI) Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Holzforschung Vol. 73 ( 9 ) page： 817 - 826 2019.9

Language：English Publishing type：Research paper (scientific journal)

© 2019 Walter de Gruyter GmbH, Berlin/Boston. As the strength of wood is greatly affected by its three-dimensional (3D) grain angles (the dive angle and the surface angle), the wood industry today requires automatic, rapid, and robust measurement techniques for measuring them simultaneously. In the present study, a near infrared spatially and spectrally resolved imaging (NIR-SSRI) system was designed in a line scan model, mainly including an NIR hyperspectral imaging camera and a halogen spotlight source (Ø 1 mm). Spatially resolved diffuse reflectance images at three target wavelengths (1002 nm, 1217 nm, and 1413 nm) were obtained from Hinoki cypress [Chamaecyparis obtusa (Siebold & Zucc.) Endl.] samples at various (0°, 3°, 6°, ⋯ 45°) dive angles and surface angles (0°, 3°, 6°, ⋯ 45°). The scattering patterns caused by the "tracheid effect" were almost elliptical. Subsequently, nonlinear least squares fitting was used to determine their eccentricities (e) and rotation angles (θ). The e values at each selected wavelength were highly correlated with the dive angle reference values; and the global identification model developed using Gaussian process regression (GPR) under five-fold cross-validation (CV) reached a determination coefficient (r2) of 0.98 with a root mean square error (RMSE) of 2.2°. On the other hand, local surface angle identification models developed using linear regression analysis achieved determination coefficients higher than 0.90 on r2 and an RMSE of CV lower than 3.8° when the dive angle was lower than 30°.

DOI： 10.1515/hf-2018-0273

Determination of Dielectric Function of Water in THz Region in Wood Cell Wall Result in an Accurate Prediction of Moisture Content Reviewed

Wang Han, Inagaki Tetsuya, Hartley Ian D, Tsuchikawa Satoru, Reid Matthew

JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES Vol. 40 ( 6 ) page： 673 - 687 2019.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SPRINGER

This report follows up previous work that presented a model for the simultaneous detection of moisture content and density of wood using Terahertz time-domain spectroscopy. A significant improvement in the prediction accuracy of the model is demonstrated by including a moisture content-dependent dielectric function for the water within the wood samples. Justification for using the dielectric function is presented, the prediction accuracy is quantified, and the results compared with prior work.

DOI： 10.1007/s10762-019-00594-0

A new approach based on a combination of capacitance and near-infrared spectroscopy for estimating the moisture content of timber Reviewed

Vu Thi Hong Tham, Inagaki Tetsuya, Tsuchikawa Satoru

WOOD SCIENCE AND TECHNOLOGY Vol. 53 ( 3 ) page： 579 - 599 2019.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The moisture content (MC) of wood influences its material properties. Determination of MC is essential in both the research and manufacturing fields. This study examined a nondestructive method for estimating MC rapidly and effectively. A capacitance sensor and a near-infrared (NIR) spectrometer were used to measure the MC of Japanese cedar and Japanese cypress timber. High-frequency capacitance (20MHz) and NIR spectral absorption (908-1676nm) data were collected for cross section and tangential section, as well as for the whole-sample average, in two MC ranges: from the green to the fiber saturation point (FSP) and from FSP to air-dried state. The results indicated that when standard error of prediction (SEP) is compared, the performance in [FSP to air-dried state] was better; when coefficient of determination in cross-validation (Rval2) and residual predictive deviation in cross-validation (RPDval) were compared, the performance in [Green to FSP] was better. Statistical analysis was performed using multiple linear regression and partial least squares. Combining capacitance and NIR absorbance at two wavelengths (Capacitance+NIR-MLR calibration) from the green to FSP was the best calibration yielding the most promising results: Rval2=0.96, SEP=5.20% and RPDval=4.97 on the cross section of samples. The results were higher than those of other calibrations in R-2 and SEP and RPD values. The NIR-PLS calibration performed better than others with quite good R-2, lower SEP and higher RPD in the MC range from FSP to air-dried state. The first calibration using only capacitance of wood was good in the first range of MC, but it is not good in the second range (R-2 under 0.5). Depending on the MC range, the performance of each calibration was different. In both MC ranges, the results on the cross section were higher than on the tangential section due to the anisotropic characteristics of wood material. From Capacitance+NIR-MLR calibration, the predicted models were developed using multiple linear regression and logarithmic regression. Results suggest the possibility of developing a new portable device combining a capacitance sensor and NIR spectroscopy to accurately predict the MC of wood.

DOI： 10.1007/s00226-019-01077-0

Rapid identification of wood species by near infrared spatially-resolved spectroscopy (NIR-SRS) based on hyperspectral imaging (HSI) Reviewed

Ma, T.; Inagaki, T.; Ban, M.; Tsuchikawa, S.

Holzforschung Vol. 73 ( 4 ) page： 323 - 330 2019.4

Near infrared estimation of concentration of ginsenosides in Asian ginseng Reviewed

Inagaki Tetsuya, Katayama Norihisa, Cho Rae-Kwang, Chen Xijun, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 27 ( 2 ) page： 115 - 122 2019.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

In this study, the feasibility of near infrared reflectance spectroscopy for the quality evaluation of the main bioactive compounds, ginsenosides, in Panax ginseng was examined. Second derivative NIR spectra of standard reagents of ginsenoside Rg(1), Re, Rb-1, Rc, Rb-2 and Rd were used for analysis. Characteristic bands were observed at around 5250 cm(-1) in the spectra of ginsenoside Rg(1) group (including Rg(1) and Re); however, this was not to be observed on the spectra of ginsenoside Rb-1 group (including Rb-1, Rc, Rb-2 and Rd). PLS regression models were constructed of air-dry ginseng powder samples and ginsenoside content in ginsengs was determined by HPLC methods. The calibration models covered various types of ginseng (white ginseng, red ginseng and bleached ginseng) from various cultivated areas (Japan, China and Korea) and were well established for each kind of ginsenoside. It was shown that NIR spectroscopy can be used for the accurate prediction of ginsenoside.

DOI： 10.1177/0967033518814851

Effect of knots and holes on the modulus of elasticity prediction and mapping of sugi (Cryptomeria japonica) veneer using near-infrared hyperspectral imaging (NIR-HSI) Reviewed Open Access

Imran Arra d. Sofianto, Tetsuya Inagaki, Te Ma, Satoru Tsuchikawa

Holzforschung Vol. 73 ( 3 ) page： 259 - 268 2019.3

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

© 2019 Walter de Gruyter GmbH, Berlin/Boston. Naturally occurring knots reduce the mechanical strength of wood. Veneers from sugi (Cryptomeria japonica) served as research material to study the effect of knots and holes. Veneer samples were first subjected to a three-point bending test to obtain measured modulus of elasticity (MOE) values. Then, near-infrared (NIR) hyperspectral imaging (HSI) was used to construct a prediction model and map the predicted MOE values. This is the first attempt for MOE prediction from the entire veneer surface based on NIR-HSI technology, while the mathematical part relies on chemometrics and cross-validation partial least squares regression (CV-PLSR). Maps of MOE prediction values could distinguish between latewood (LW) and earlywood (EW), as well as between a sound knot and a dead knot.

DOI： 10.1515/hf-2018-0060

DETERMINATION OF CAROTENOIDS AND DOBI CONTENT IN CRUDE PALM OIL BY SPECTROSCOPY TECHNIQUES: COMPARISON OF RAMAN AND FT-NIR SPECTROSCOPY Reviewed Open Access

Nokkaew Rayakorn, Punsuvon Vittaya, Inagaki Tetsuya, Tsuchikawa Satoru

INTERNATIONAL JOURNAL OF GEOMATE Vol. 16 ( 55 ) page： 92 - 98 2019.3

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：GEOMATE INT SOC

Crude palm oil (CPO) is a rich source of carotenoids which are a precursor of vitamin A as an important antioxidant. Carotenoids and Deterioration Of Bleachability Index (DOBI) are important factors to indicated quality of CPO. The conventional method for DOBI and carotenoids determination use UV-Vis spectrophotometry and HPLC, respectively which methods use solvents and spend time for analysis. This research interests Raman and FT-NIR spectroscopy for carotenoids and DOBI determination due to those techniques are an alternative technique for rapid measurement, non-destruction of material, and environmental suitability. The results indicated that Raman is better for determination than FT-NIR spectrometry. In Raman analysis, multiplicative scatter correction (MSC) and standard normal variate (SNV) treated methods were the best models for carotenoids and DOBI, respectively. The bands of carotenoids were at 1,100 and 1,500 cm(-1) wavenumber. Validation on carotenoids produced 0.94 of correlation coefficient (R), 0.88 of coefficient of determination (R-2), 40.65 ppm of root mean square error of prediction (RMSEP) and 3.25 of the ratio of standard error of prediction to standard deviation (RPD). The validation of DOBI produced 0.76 of R, 0.57 of R-2, 0.31 of RMSEP, 1.92 of RPD of 1.92. The limitation of carotenoids and DOBI determination using FT-NIR is having sufficient concentration of carotenoids for analysis. In addition, data for various samples regarding location, season, and oil palm species are important to build models for precise prediction.

DOI： 10.21660/2019.55.4813

Non-destructive evaluation of wood stiffness and fiber coarseness, derived from SilviScan data, via near infrared hyperspectral imaging Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

Journal of Near Infrared Spectroscopy Vol. 26 ( 6 ) page： 398 - 405 2018.12

Language：English Publishing type：Research paper (scientific journal)

© The Author(s) 2018. Near infrared hyperspectral imaging combined with partial least squares regression analysis was used to evaluate wood stiffness (modulus of elasticity) and fiber coarseness. Five samples with normal wood and compression wood collected from two Japanese Cedar (Cryptomeria japonica) trees were analyzed. To achieve high reliability of the prediction values, a SilviScan system (X-ray densitometry, X-ray diffractometry, and optical microscopy) with the high spatial resolution was used for measuring reference data. The measurement interval for modulus of elasticity and fiber coarseness was 1µm and 25 µmm, respectively. After spectral pre-treatment and key wavelengths selection, partial least squares analysis was applied to calibrate near infrared data to reference values. The determination coefficient (RCV2) of modulus of elasticity was 0.66 with a root mean square error of cross validation (RMSECV) of 1.80 GPa. For the constructed fiber coarseness calibration model, RCV2 and RMSECV were 0.62 and 35.02 µmm/g, respectively. Finally, modulus of elasticity and fiber coarseness mapping results show detailed information (156 µmm/pixel) at the grown ring level. The differences among earlywood, latewood, and compression wood were all well identifiable.

DOI： 10.1177/0967033518808053

NIR estimation of concentration of ginsenosides in Asian ginseng Reviewed

Inagaki, T.; Katayama, N.; Cho, R.; Chen, X.; Tsuchikawa S.

Journal of Near Infrared Spectroscopy 2018.12

Inspection of Microfibril Angle of Sugi Wood by THz-TDS Reviewed

Wang H, Tsuchikawa S, Inagaki T

International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz Vol. 2018-September 2018.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz

Wood as a biological material has large differences in individual properties, and terahertz time-domain spectroscopy (THz-TDS) provide a new possibility for the wood products industry since THz exhibits high transparency to wood with big birefringence and diattenuation. By using the complex refractive index and absorption coefficient, THz is excepted to estimate important properties such as fiber orientation, microfibril angle (MFA) etc. simultaneously. In this study, sugi was used as sample because of its simple structure. Density and moisture content were predicted by using the real part of complex refractive index combined with absorption coefficient and showed a high correlation between measured and predicted values, prediction of MFA is still an ongoing mission.

DOI： 10.1109/IRMMW-THz.2018.8510303

Quality Evaluation of Engineered Wood by THz-TDS Reviewed

Kashima M, Tsuchikawa S, Inagaki T

International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz Vol. 2018-September 2018.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz

This study attempts simultaneous prediction of grain angle, density and moisture content by THz time domain spectroscopy (THz-TDS) which has sufficient spatial resolution and transparency for wood. Terahertz waves transmitted through wood contain information on moisture content, density, grain angle and crystallinity of the sample. In this study, we measured spectra of 14 kinds of wood (5 soft wood, 9 hard woods) at various moisture contents and air-dried douglas fir while rotating the sample against the polarization of the terahertz wave. It was shown that the fiber orientation, density and moisture content of wood can be predicted simultaneously from the calculated complex permittivity.

DOI： 10.1109/IRMMW-THz.2018.8510155

Optical characteristics of Douglas fir at various densities, grain directions and thicknesses investigated by near-infrared spatially resolved spectroscopy (NIR-SRS) Reviewed

Te Ma, Gary Schajer, Tetsuya Inagaki, Zarin Pirouz, Satoru Tsuchikawa

Holzforschung Vol. 72 ( 9 ) page： 789 - 796 2018.9

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Walter de Gruyter GmbH

A near-infrared spatially resolved spectroscopy (NIR-SRS) system, also called the hyperspectral imaging system, was applied in a line scanning model combined with a concentrated halogen light source (Ø 1 mm), and spatially resolved reflectance images of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] wood were obtained. The samples with various densities, grain directions and thicknesses were observed in the NIR range of 1000-1600 nm. Then, a nonlinear curve-fitting algorithm was applied based on the steady-state diffusion theory model to estimate the absorption coefficient (μa), and reduced scattering coefficients ( μ′s ${\\mu '-s}$ ) both parallel and perpendicular to the grain direction at each measurement position. The absorption scattering coefficients at 1457 nm and two kinds of reduced scattering coefficients at 1002 nm were highly correlated with wood densities measured by an X-ray densitometer. The correlation coefficients were 0.953 and 0.987 for 3 mm and 5 mm samples, respectively, while three optical profiles were combined. It can be concluded that NIR-SRS is a fast and simple method for measuring the optical characteristics of softwood, although it has a non-homogeneous cellular structure. Sub-surface density and grain direction could be predicted with satisfactory accuracy based on a few key wavelengths without relying on multivariate statistical analysis.

DOI： 10.1515/hf-2017-0213

Determination of physical and chemical properties and degradation of archeological Japanese cypress wood from the Tohyamago area using near-infrared spectroscopy Reviewed Open Access

Tetsuya Inagaki, Hitoshi Yonenobu, Yuuki Asanuma, Satoru Tsuchikawa

Journal of Wood Science Vol. 64 ( 4 ) page： 347 - 355 2018.8

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Tokyo

Here, we evaluated the application of near-infrared (NIR) spectroscopy for estimating the degradation level of archeological wood samples from the Tohyamago area, the dendrochronological ages of which were also determined. The wood samples were radially cut from three logs obtained from the Tohyamago area. NIR reflectance spectra were measured from the tangential faces of air- and oven-dried wood samples using a Fourier transform NIR spectrophotometer. The second derivative spectra within the wavenumber range of 6400–5200 cm−1, in which the effect of moisture content in wood is suspected to be insignificant, showed a characteristic behavior with age. By comparing the second derivative spectral change in our wood samples with that in wood degraded by aging, thermal treatment, fungal attack, and lightning reported in the literature, we found that the second derivative spectra of wood samples from one log was similar to those of wood degraded by hygro-thermal treatment, whereas those of wood samples from another log was similar to those of wood degraded by brown-rot fungi. The physical and chemical properties of archeological wood were well predicted using a combination of partial least square regression analysis and NIR spectroscopy.

DOI： 10.1007/s10086-018-1718-8

Noncontact evaluation of soluble solids content in apples by near-infrared hyperspectral imaging Reviewed

Te Ma, Xinze Li, Tetsuya Inagaki, Haoyu Yang, Satoru Tsuchikawa

Journal of Food Engineering Vol. 224 page： 53 - 61 2018.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

Near-infrared (NIR) hyperspectral imaging was used to evaluate soluble solids content (SSC) in ‘Fuji’ apples [Malus sylvestris (L.) Mill. var. domestica (Borkh. Mansf.)]. Eighty ‘Fuji’ apples were analyzed by collecting four small block samples from each one (approximately 2.0 cm × 2.0 cm × 1.5 cm). Partial least squares (PLS) regression analysis was performed to determine the relation between SSC reference data and NIR spectral data measured from each sample. The cross-validation coefficient of determination (r2) between predicted and measured SSC values is 0.89 with a root mean squared error of cross-validation (RMSECV) of 0.55%. Then, we successfully mapped SSC at a high spatial resolution (375 μm per pixel). In addition, the absorption and reduced scattering coefficients of the measured samples were determined based on a diffusion theory model. The absorption coefficients are positively correlated to the SSC values (chemical information), whereas water cored tissue content (physical information) causes a characteristic change in light scattering coefficients. The fitting results were validated by Monte Carlo simulation, and the light penetration depth in ‘Fuji’ apples was estimated to be around 0.33 cm at 1198 nm and 0.17 cm at 1450 nm, respectively.

DOI： 10.1016/j.jfoodeng.2017.12.028

Selective assessment of duplex heat-treated wood by near-infrared spectroscopy with principal component and kinetic analyses Reviewed Open Access

Tetsuya Inagaki, Yuuki Asanuma, Satoru Tsuchikawa

Journal of Wood Science Vol. 64 ( 1 ) page： 6 - 15 2018.2

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Tokyo

We selectively assessed the thermal and hygrothermal treatment times of duplex heat-treated samples from the softwood hinoki cypress (Chamaecyparis obtusa) and the hardwood Japanese zelkova (Zelkova serrata) using near-infrared (NIR) spectroscopy with principal component analysis (PCA) and spectral-kinetic analysis. Wood samples from each species were thermally or hygrothermally treated at 120, 130, 150, and 180 °C, and the second-derivative spectra of these samples in the 6300–5450 cm−1 range, where moisture content has the smallest effect, were then subjected to PCA. The master curve that was calculated by kinetic analysis successfully explained changes in the first principal component (PC1) scores with thermal treatment time for all temperatures. The angles between the PC1 loadings that explained the spectral variation due to thermal and hygrothermal treatment were 79° for hinoki and 80° for zelkova. Thus, calculation of the inner product between the second-derivative spectra of duplex heat-treated wood and a loading vector that explained the spectral variation due to thermal or hygrothermal treatment allowed us to selectively assess the thermal and hygrothermal treatment times.

DOI： 10.1007/s10086-017-1670-z

A novel combined application of capacitive method and near-infrared spectroscopy for predicting the density and moisture content of solid wood Reviewed

Effect of cellular structure on the optical properties of wood Reviewed Open Access

Mayuka Ban, Tetsuya Inagaki, Te Ma, Satoru Tsuchikawa

Journal of Near Infrared Spectroscopy Vol. 26 ( 1 ) page： 53 - 60 2018.2

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE Publications Ltd

To construct robust calibrations of wood properties by near infrared spectroscopy, one must independently evaluate the spectral contributions of light absorption and light scattering. However, the light propagation in wooden cellular structures is difficult to interpret because these structures are complex, heterogeneous, and anisotropic. This study investigates the reduced scattering coefficients of softwood and hardwood (with ring-porous or diffuse-porous vessels) at 846 nm by time-resolved spectroscopy. It also evaluates the effect of wooden cellular structure and air-dry density on the light propagation. After determining the reduced scattering coefficients, we observed cross-sectional microscopic images of the wood samples. Eighty-five percent of the variation in the reduced scattering coefficients was explainable by the air-dry density, area ratio of the cell wall, and the median pore area. Monte Carlo simulations of the light propagation through wood revealed that most of the photon transport occurs in the cell-wall substance.

DOI： 10.1177/0967033518757233

Vu Thi Hong Tham, Tetsuya Inagaki, Satoru Tsuchikawa

Wood Science and Technology Vol. 52 ( 1 ) page： 115 - 129 2018.1

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Verlag

The use of a capacitive method and near-infrared (NIR) spectroscopy to simultaneously predict the density and moisture content (MC) of wood samples was investigated. Prediction accuracy of both methods was individually investigated by multivariate analyses. The capacity and absorbance at two wavelengths in the NIR range were combined to predict both the properties by the specific models. All wavelength combinations in the range of 908–1676 nm were tested, and the best combination yielding the highest coefficient of determination (R2) was chosen. This novel method showed a strong correlation between predicted and measured data, independent of sample thickness and wood species. The prediction accuracy of the wood samples, from green wood to oven-dried conditions, showed promising results for all thicknesses, with R2 = 0.79, root-mean-square error of cross-validation (RMSECV) = 0.10 g/cm3, and residual predictive deviation (RPD) = 2.22 for density and R2 = 0.80, RMSECV = 25.70%, and RPD = 2.22 for MC. In the case of below fiber saturation point to oven-dried state, R2 value was slightly decreased in the prediction of MC and slightly increased in the prediction of density, but RMSECV of MC declined significantly (maximum 5.46%) compared to the range of MC from saturated point (maximum 39.56%). These results were considerably better than those obtained by modeling the capacitive or NIR method individually, and improvement was particularly apparent in estimating density. The results suggest the possibility of a new device combining the capacitive method and NIR spectroscopy to predict density and MC more accurately.

DOI： 10.1007/s00226-017-0974-x

Near-infrared hyperspectral imaging for classification of mung bean seeds Reviewed Open Access

Kaewkarn Phuangsombut, Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa, Anupun Terdwongworakul

International Journal of Food Properties Vol. 21 ( 1 ) page： 799 - 807 2018

Language：English Publishing type：Research paper (scientific journal)

©2018 Kaewkarn Phuangsombut, Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa and Anupun Terdwongworakul. Hard mung bean seeds pose a problem in the sprouting process as they develop mold and infect neighboring seeds. Near-infrared hyperspectral imaging combined with partial least squares discriminant analysis was applied to develop a classifying model to separate hard mung beans from normal ones. The orientation of the measured beans was found to affect the classification result. The optimal partial least squares discriminant analysis model based on all orientations resulted in a correlation coefficient (R) of 0.919 with a root mean squared error of prediction of 0.197. The non-germinative parts were mapped and were concentrated at one end of the bean. Finally, a germinability index was proposed according to the proportion of colored areas between the germinative and non-germinative parts from the hyperspectral imaging results.

DOI： 10.1080/10942912.2018.1476378

Dynamic behavior of wood chemical components under drying process measured by near infrared spectroscopy Reviewed

Inspection of Microfibril Angle of Sugi Wood by THz-TDS Reviewed

Wang H., Tsuchikawa S., Inagaki T.

2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) page： . 2018

Effect of knots and holes on the modulus of elasticity prediction and mapping of sugi (Cryptomeria japonica) veneer using near-infrared hyperspectral imaging (NIR-HSI) Reviewed

114. Sofianto, I. A.; Inagaki, T.; Ma, T.; Tsuchikawa, S.

Holzforschung 2018

Quality Evaluation of Engineered Wood by THz-TDS Reviewed

Kashima Moe, Tsuchikawa Satoru, Inagaki Tetsuya

2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) page： . 2018

Non-destructive evaluation of wood stiffness and fiber coarseness, derived from SilviScan data, via near infrared hyperspectral imaging Reviewed

Ma, T.; Inagaki, T.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 26 ( 6 ) page： 398-405 2018

Inspection of Microfibril Angle of Sugi Wood by THz-TDS Reviewed

Wang H., Tsuchikawa S., Inagaki T.

2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) page： . 2018

Quality Evaluation of Engineered Wood by THz-TDS Reviewed

Kashima Moe, Tsuchikawa Satoru, Inagaki Tetsuya

2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) page： . 2018

Shiho Sugii, Takaaki Fujimoto, Harusa Tsutsumi, Tetsuya Inagaki, Satoru Tsuchikawa

Journal of Near Infrared Spectroscopy Vol. 25 ( 6 ) page： 400 - 406 2017.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SAGE Publications Ltd

This study examined the dynamic behavior of wood chemical components during the drying process using near infrared spectroscopy. Principal component analysis and generalized two-dimensional correlation spectroscopy were applied to identify significant absorption bands from the heavily overlapping near infrared spectra. The near infrared spectra were successively acquired over the moisture content range of 60-11%. The principal component analysis scores indicated that the wood-water interaction in the moisture content range of 60-46% significantly differed from that in the range of 45-11%. The synchronous 2D correlation spectrum constructed from the spectra in the moisture content range of 60-46% revealed that the cell wall components and water molecules responded to the drying process even though the wood exceeded the fiber saturation point. In the moisture content range of 45-11%, the H-bonded OH groups in the crystalline region of cellulose clearly increased with the decrease in bound water. Moreover, the sequential order of events was also clarified from the asynchronous spectrum.

DOI： 10.1177/0967033517733379

Temperature dependence of wood photodegradation monitored by infrared spectroscopy Reviewed

High-Resolution and Non-destructive Evaluation of the Spatial Distribution of Nitrate and Its Dynamics in Spinach (Spinacia oleracea L.) Leaves by Near-Infrared Hyperspectral Imaging Reviewed

Yang, H.; Inagaki, T.; Ma, T.; Tsuchikawa, S.

frontiers in Plant Science Vol. 8 page： 10.3389/fpls.2017.01937 2017.11

Denes Varga, Laszlo Tolvaj, Satoru Tsuchikawa, Laszlo Bejo, Edina Preklet

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY Vol. 348 page： 219 - 225 2017.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

The temperature dependence of the photodegradation of hardwoods (beech, Fagus sylvatical. and poplar, Populus x euramericana cv. Pannonia) and softwoods (Scots pine, Pinus sylvestris L and spruce, Picea abies Karst.) was investigated. Samples were irradiated by a strong UV emitter mercury lamp at 30 degrees C, 80 degrees C, 120 degrees C and 160 degrees C. A series of samples was treated in the same chamber set to 30 degrees C, 80 degrees C, 120 degrees C and 160 C but without light irradiation (pure thermal treatment). The chemical changes were detected by infrared spectroscopy. The same light irradiation generated much greater absorption change at 160 degrees C than at 30 degrees C. The simultaneous thermal and UV treatment generated much greater absorption increase in the whole investigated infrared region than the sum of absorption increases generated by the individual thermal treatment and UV radiation, separately. Softwoods were more sensitive to the light irradiation at elevated temperatures than hardwoods. Results revealed that four bands around 1770, 1750, 1720 and 1690 cm(-1) emerged in the unconjugated carbonyl region as a result of the UV irradiation at elevated temperatures. The intensity change of these bands is highly dependent on the wood species. Absorption increase was found at 1066 and 1035 cm(-1). (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotochem.2017.08.040

Modulus of elasticity prediction model on sugi (Cryptomeria japonica) lumber using online near-infrared (NIR) spectroscopic system Reviewed

Modulus of elasticity prediction model on sugi (Cryptomeria japonica) lumber using online near-infrared (NIR) spectroscopic system Reviewed

Sofianto, I. A.; Inagaki, T.; Kato, K.; Itoh, M.; Tsuchikawa, S.

International Wood Products Journal Vol. 8 ( 4 ) 2017.10

Sofianto Imran Arra'd, Inagaki Tetsuya, Kato Kouchi, Itoh Mariya, Tsuchikawa Satoru

INTERNATIONAL WOOD PRODUCTS JOURNAL Vol. 8 ( 4 ) page： 193 - 200 2017.10

Stiffness and Moisture Content Prediction Model of Wooden Veneer Using Fast Online Near-Infrared (NIR) Spectroscopic System Reviewed

Sofianto, I. A, Inagaki, T, Itoh, M, Tsuchikawa, S

Forestry Research and Engineering: International Journal Vol. 1 ( 2 ) page： 1-5 2017.9

Stiffness and Moisture Content Prediction Model of Wooden Veneer Using Fast Online Near-Infrared (NIR) Spectroscopic System Reviewed

Sofianto, I. A.; Inagaki, T.; Itoh, M.; Tsuchikawa, S.

Forestry Research and Engineering: International Journal Vol. 1 ( 2 ) page： 1-5 2017.9

High spatial resolution and non-destructive evaluation of wood density and microfibril angle by NIR hyperspectral imaging

Ma, T.; Inagaki, T.; Tsuchikawa, S.

Vol. 28 ( 5 ) page： 7-12 2017.6

High spatial resolution and non-destructive evaluation of wood density and microfibril angle by NIR hyperspectral imaging Invited Reviewed

Ma, T, Inagaki, T, Tsuchikawa, S

Vol. 28 ( 5 ) page： 7-12 2017.6

Segregating wood wastes by repetitive principal component analysis of near infrared spectra Reviewed

Hikaru Kobori, Sakura Higa, Satoru Tsuchikawa, Yoichi Kojima, Shigehiko Suzuki

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 25 ( 3 ) page： 180 - 187 2017.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

To improve the recycling rate of wooden materials, it is necessary to classify wood waste by disposal method and usage. In the industrial manufacture of these materials, rapid and accurate determination of their chemical and physical properties is critical for a stable supply of wood products with reliable quality. In this study, we investigated a discriminant analysis process for waste wood products using hyperspectral imaging with a newly developed repetitive principal component analysis. Hyperspectral images of four types of wood waste (plywood coated with resin, preservative-treated wood, hardwood and softwood) were acquired. The mean spectrum of each sample was extracted from a hypercube in order to build a classification model. A novel classification method based on principal component analysis, named repetitive principal component analysis, was developed. A total of three repetitions of principal component analysis were performed to classify the four types of wood waste. Cross-validated results of repetitive principal component analysis resulted in classifications greater than 85% for any of the four wood waste types. The discriminant model was then applied to single-pixel spectra of the hypercube to form a prediction map. Hyperspectral imaging, with the aid of the new repetitive principal component analysis discriminant analysis, is a powerful tool in wood recycling processes.

DOI： 10.1177/0967033517714344

Calibration of SilviScan data of Cryptomeria japonica wood concerning density and microfibril angles with NIR hyperspectral imaging with high spatial resolution Reviewed

Te Ma, Tetsuya Inagaki, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 71 ( 4 ) page： 341 - 347 2017.4

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Wood density and microfibril angle (MFA) are strongly correlated with wood stiffness, swelling/shrinkage, and its anisotropy. Understanding the spatial distribution of these data is critical for solid timber applications. In this study, near-infrared (NIR) hyperspectral imaging has been calibrated for evaluation of wood density and MFA in an effective manner. Briefly, five wood samples collected from both normal wood (NW) and compression wood (CW) moieties of two different Cryptomeria japonica trees were analyzed. Partial least squares (PLS) regression analysis was performed to determine the relationship between X-ray densitometry data obtained by SilviScan and NIR spectra, and cross-validation (leave-one-out) approach served for prediction performances. The validation coefficient of determination (r(2)) between the predicted densities by the NIR technique and the X-ray data was 0.83 with a root mean squared error of cross-validation (RMSECV) of 105.2 kg m(-3). Regarding MFA, the r(2) was 0.77 and RMSECV 5.36 degrees. Wood density was successfully maped as well as the MFA at a high spatial resolution. As a result, the detection of annual growth ring features and evaluation of aspects of heterogeneous wood quality has been facilitated. The mapping results were visually checked by looking at the difference between earlywood (EW) and latewood (LW) for density and by means of the Maule color reaction indicating high lignin contents in CW in terms of MFA validation as CWs have high MFA values.

DOI： 10.1515/hf-2016-0153

The effect of path length, light intensity and co-added time on the detection limit associated with NIR spectroscopy of potassium hydrogen phthalate in aqueous solution Reviewed

Temperature dependence of wood photodegradation monitored by infrared spectroscopy

Varga, D, Tolvaj, L, Tsuchikawa, S, Bejoc, L, Prekleta, E

Journal of Photochemistry and Photobiology A: Chemistry Vol. 348 page： 219-225 2017

Dynamic behavior of wood chemical components under drying process measured by near-infrared spectroscopy Reviewed

Sugii, S.; Fujimoto, T.; Tsutsumi, H.; Inagaki, T.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 25 ( 6 ) page： 400-406 2017

Temperature dependence of wood photodegradation monitored by infrared spectroscopy Reviewed

Varga, D., Tolvaj, L.; Tsuchikawa, S.; Bejoc, L.; Prekleta, E.

Journal of Photochemistry and Photobiology A: Chemistry Vol. 348 page： 219-225 2017

Segregating wood wastes by repetitive principal component analysis of near infrared spectra Reviewed

Kobori, H.; Higa, S.; Tsuchikawa, S., Kojima, Y.; Suzuki, S.

Journal of Near Infrared Spectroscopy Vol. 25 ( 3 ) page： 180-187 2017

The effect of path length, light intensity and co-added time on the detection limit associated with NIR spectroscopy of potassium hydrogen phthalate in aqueous solution Reviewed

Inagaki, T.; Watanabe, T.; Tsuchikawa S.

PLOS ONE page： https://doi.org/10.1371/journal.pone.0176920 2017

Classification of mung bean seeds for sprout production using near-infrared spectroscopy and hyperspectral imaging Reviewed

Phuangsombut, K.; Terdwongworakul, A.; Suttiwijitpukdee, N.; Phuangsombut A.; Tsuchikawa S.; Inagaki T.; Ma T.

Thai Society of Agricultural Engineering Journal Vol. 23 ( 1 ) page： 23-29 2017

Inagaki Tetsuya, Watanabe Tomoko, Tsuchikawa Satoru

PLOS ONE Vol. 12 ( 5 ) page： e0176920 2017

Classification of mung bean seeds for sprout production using near-infrared spectroscopy and hyperspectral imaging Reviewed

Phuangsombut, K., Terdwongworakul, A., Suttiwijitpukdee, N., Phuangsombut A., Tsuchikawa S., Inagaki T., Ma T.

Thai Society of Agricultural Engineering Journal Vol. 23 ( 1 ) page： 23-29 2017

Development of Multiple Evaluation Method of Wood Pulp in Paper by Near Infrared Spectroscopy

Kawabe Chika, Fukasawa Hiroyuki, Inagaki Tetsuya, Tsuchikawa Satoru

JAPAN TAPPI JOURNAL Vol. 71 ( 3 ) page： 326 - 334 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY

Near infrared spectroscopy （NIRS） has been applied in some fields such as medicines, chemicals and ag ricultural products. In this report, NIRS was applied to paper sheets to analyze the contained pulp qualita tively and quantitatively. LBKP, NBKP, CTMP and others could be classified by principal component analysis （PCA） for NIR spectra. The blend ratio of LBKP, NBKP and CTMP in the both mixtures of LBKP and CTMP, and NBKP and CTMP could be determined respectively by partial least squares regression （PLSR）for NIR spectra within the coefficient of determination （R2 value） of 0.98. Furthermore, the ratio of mixture of KP and another pulp on the paper could be determined somewhat correctly even if we do not know what kinds of pulp were contained. NIRS could also be used to estimate the drainability of LBKP; that is, the pre dicted value was very close to the measured value. NIRS was also applied to evaluate the degree of degrada tion of pulp. PCA for NIR spectra of LBKP has revealed the linear relationships between recycled times and score.The NIR technique is faster than staining techniques, and does not require special training. If we could have tested a wider variety of samples, if we had more time, and if we could have optimized the analysis con dition, it would be possible to estimate more precisely.

DOI： 10.2524/jtappij.71.326

Development of Multiple Evaluation Method of Wood Pulp in Paper by Near Infrared Spectroscopy

Dynamic behavior of wood chemical components under drying process measured by near-infrared spectroscopy

Sugii, S, Fujimoto, T, Tsutsumi, H, Inagaki, T, Tsuchikawa, S

Journal of Near Infrared Spectroscopy Vol. 25 ( 6 ) page： 400-406 2017

Segregating wood wastes by repetitive principal component analysis of near infrared spectra

Kobori, H, Higa, S, Tsuchikawa, S, Kojima, Y, Suzuki, S

Journal of Near Infrared Spectroscopy Vol. 25 ( 3 ) page： 180-187 2017

JAPAN TAPPI JOURNAL Vol. 71 ( 3 ) page： 318 - 325 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T., Kashima M., Tsuchikawa S.

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector

Terahertz (THz) radiation has the potential to be a useful tool for sensing and imaging of wood because wood is relatively transparent at these frequencies (below about 1 THz). In this study, demonstration of simultaneous prediction of solid wood density, moisture content and fiber orientation, all of which are critical in manufacturing operations, of 14 species including softwood and hard wood was accomplished using terahertz time-domain spectroscopy (THz-TDS). THz measurements of wood at various moisture contents were taken for 19 orientations of the THz field (0-180o with 10o step) with respect to the visible grain. The real part of refractive index value and absorption cosfficient had strong correlation with density and moisture content of the wood. A strong correlation between measured and predicted values for density and moisture content were observed. The possibility for the estimation of fiber orientation using the birefringence property of wood were shown.

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T., Kashima M., Tsuchikawa S.

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Estimation of wood density, moisture content and fiber orientation by THz time domain spectroscopy Reviewed

Inagaki T, Kashima M, Tsuchikawa S

28th International Conference on Wood Science and Technology, ICWST 2017: Implementation of Wood Science in Woodworking Sector page： 3 - 6 2017

Coming full circle: back to basics in the application of near infrared spectroscopy to the forest and wood products sector

Roger Meder, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 24 ( 6 ) page： V - VII 2016.12

Determination of optical parameters and moisture content of wood with visible-near infrared spectroscopy Reviewed

Ataollah Haddadi, Guillaume Hans, Brigitte Leblon, Zarin Pirouz, Satoru Tsuchikawa, Joseph Nader, Kevin Groves

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 24 ( 6 ) page： 571 - 585 2016.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

We used the Kubelka-Munk theory equations for calculating the absorption coefficient [K-lambda], the scattering coefficient [S-lambda], the transport absorption [sigma(lambda a)], the reduced scattering coefficient [sigma(lambda s)(1 -g)] and the penetration depth [delta(lambda)] from visible-near infrared reflectance spectra acquired over thin samples of quaking aspen and black spruce conditioned at three different moisture levels. The computed absorption and scattering coefficients varied from 0.1 mm(-1) to 4.0 mm(-1) and from 5.5 mm(-1) to 10.0 mm(-1), respectively. The absorption coefficients varied according to the absorption band, but the scattering coefficients decreased slowly towards high wavelengths. The sample moisture content was then estimated using the partial least squares (PLS) regression method from the K-lambda and/ or S-lambda spectra, and the resulting PLS models were compared to those obtained with raw and transformed [multiplicative scatter corrected (MSC), first and second derivative] absorption spectra. The best PLS models for black spruce, quaking aspen and both species were obtained when only the 800-1800 nm range was used with the raw or MSC spectra. They led to a root mean square error of cross validation (RMSECV) of 1.40%, 1.09% and 1.23%, respectively, and to a coefficient of determination (R-CV(2)) higher than 0.94. We also found that the K-lambda spectra between 800 nm and 1800 nm can provide PLS models having an acceptable accuracy for moisture content estimation (R-CV(2) = 0.83 and RMSECV = 2.32%), regardless of the species.

DOI： 10.1255/jnirs.1174

Optical properties of drying wood studied by time-resolved near-infrared spectroscopy Reviewed

Konagaya Keiji, Inagaki Tetsuya, Kitamura Ryunosuke, Tsuchikawa Satoru

OPTICS EXPRESS Vol. 24 ( 9 ) page： 9561 - 9573 2016.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Optics Express

We measured the optical properties of drying wood with the moisture contents ranging from 10% to 200%. By using time-resolved near-infrared spectroscopy, the reduced scattering coefficient μs′ and absorption coefficient μa were determined independent of each other, providing information on the chemical and structural changes, respectively, of wood on the nanometer scale. Scattering from dry pores dominated, which allowed us to determine the drying process of large pores during the period of constant drying rate, and the drying process of smaller pores during the period of decreasing drying rate. The surface layer and interior of the wood exhibit different moisture states, which affect the scattering properties of the wood.

DOI： 10.1364/OE.24.009561

NIR spectral-kinetic analysis for thermally degraded Sugi (Cryptomeria japonica) wood Reviewed

Inagaki, T; Matsuo, M; Tsuchikawa, S

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Vol. 122 ( 3 ) 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Physics A: Materials Science and Processing

Kinetic analysis was conducted on principal component scores calculated from second-derivative near-infrared (NIR) spectra of thermally treated Sugi (Cryptomeria japonica) wood samples. NIR reflectance spectra were measured for wood samples thermally treated at 90, 120, 150 and 180 °C in an air-circulating oven for periods ranging from 5 min to approximately 1.4 years. The Arrhenius approach, which involves the time–temperature superposition method, is used to understand the change in the principal component score. The master curve corresponded well with the change in principal component scores at each temperature and yielded a determination coefficient between the measured and estimated data of 0.99 for second principal component score. This report shows that kinetic analysis is useful to understand changes in the principal component score calculated from NIR spectra of wood subjected to thermal treatment.

DOI： 10.1007/s00339-016-9763-x

Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy Reviewed

Kitamura Ryunosuke, Inagaki Tetsuya, Tsuchikawa Satoru

OPTICS EXPRESS Vol. 24 ( 4 ) page： 3999 - 4009 2016.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Optics Express

The true absorption coefficient (μa) and reduced scattering coefficient (μ′s) of the cell wall substance in Douglas fir were determined using time-of-flight near infrared spectroscopy. Samples were saturated with hexane, toluene or quinolone to minimize the multiple reflections of light on the boundary between pore-cell wall substance in wood. μ′s exhibited its minimum value when the wood was saturated with toluene because the refractive index of toluene is close to that of the wood cell wall substance. The optical parameters of the wood cell wall substance calculated were μa = 0.030 mm-1 and μ′s = 18.4 mm-1. Monte Carlo simulations using these values were in good agreement with the measured time-resolved transmittance profiles.

DOI： 10.1364/OE.24.003999

Three-fibre-based diffuse reflectance spectroscopy for estimation of total solid content in natural rubber latex Reviewed

NIR Spectral-kinetic analysis for thermally degraded Sugi (Cryptomeria japonica) wood Reviewed

Inagaki T, Matsuo M, Tsuchikawa S

Applied Physics A Vol. 122 page： 208 2016.2

Inagaki Tetsuya, Nozawa Daisuke, Shimomura Yoshiaki, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 24 ( 4 ) page： 327 - 335 2016

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

It is shown that three-fibre-based diffuse reflectance spectroscopy, based on spatially resolved near infrared spectroscopy in the wavelength range 850-1060 nm, is a promising method for the measurement of quality in natural rubber latex samples. Absorbance ratios were defined as the ratio of light intensity detected at distances r and r + D from the emitter fibre. A relative absorbance ratio g was then calculated using the absorbance ratios at three wavelengths. Parameter g had a strong linear correlation with total solid content in latex (range 0.3-0.6 g g-1) with a coefficient of determination value of 0.98 and root mean square error for total solid content of 0.014 g g-1. Although the near infrared spectra measured by conventional transmission or reflectance spectroscopy were highly affected by the scattering coefficient in the sample, simulation results in this study showed that the effects of scattering in the samples on g can be reduced.

DOI： 10.1255/jnirs.1227

Non-destructive inspection of insects in chocolate using near infrared multispectral imaging Reviewed

Three fiber-based diffuse reflectance spectroscopy for estimation of total solid content in natural rubber latex

Inagaki, T, Nozawa, D, Shimomura, Y, Tsuchikawa S

Journal of Near Infrared Spectroscopy Vol. 24 page： 327-335 2016

Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy Reviewed

Kitamura, R.; Inagaki, T.; Tsuchikawa, S.

Optic Express Vol. 24 ( 4 ) page： 3999-4009 2016

Optical properties of drying wood studied by time-resolved near-infrared spectroscopy Reviewed

Konagaya, K.; Inagaki, T.; Kitamura, R.; Tsuchikawa, S.

Optic Express Vol. 24 ( 9 ) page： 9561-9573 2016

Nondestructive inspection of insects in chocolate using near infrared multispectral imaging Reviewed

Ma, T.; Kobori, H.; Katayama, N.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 24 page： 391-397 2016

Three fiber-based diffuse reflectance spectroscopy for estimation of total solid content in natural rubber latex Reviewed

Inagaki, T.; Nozawa, D.; Shimomura, Y.; Tsuchikawa S.

Journal of Near Infrared Spectroscopy Vol. 24 page： 327-335 2016

近赤外分光法を用いた紙中の木材パルプの複合的評価手法の開発 Reviewed

河部千香、深沢博之、稲垣哲也、土川覚

紙パ技協誌 Vol. 71 ( 3 ) page： 318-325 2016

Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy

Kitamura, R, Inagaki, T, Tsuchikawa, S

Optic Express Vol. 24 ( 4 ) page： 3999-4009 2016

Te Ma, Hikaru Kobori, Norihisa Katayama, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 24 ( 4 ) page： 391 - 397 2016

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

Foreign matters in food products strongly affect the commercial viability of food production companies. To monitor and improve the reliability of food production processes, fast and non-destructive online inspection methods are urgently required. In this study, we exploited the high transmittance of near infrared (NIR) light, and designed an NIR transmission-type imaging device that detects low-density foreign matters (such as insects) inside chocolate. Insect parts had consistently lower transmittance than chocolate parts. To enhance the important differences between the two parts, the images were processed using principal component analysis. Furthermore, an algorithm for detecting the insect parts was developed in conjunction with image threshold processing and Laplacian of Gaussian edge detection. A favourable detection rate (93%) was achieved using spectral regions 840-870 nm, 870-900 nm and 900-930 nm. The results suggested that NIR multispectral imaging is useful for detecting low-density matter (insects) in the chocolate manufacturing industry.

DOI： 10.1255/jnirs.1237

Creation of Novel Science by Contacting Dissimilar Field: Introduction of Near Infrared Spectroscopy as Example

近赤外分光法を用いた紙中の木材パルプの複合的評価手法の開発 Reviewed

河部千香, 深沢博之, 稲垣哲也, 土川覚

紙パ技協誌 Vol. 71 ( 3 ) page： 318-325 2016

TSUCHIKAWA Satoru

TRENDS IN THE SCIENCES Vol. 21 ( 2 ) page： 2_66 - 2_71 2016

Optical properties of drying wood studied by time-resolved near-infrared spectroscopy

Konagaya, K, Inagaki, T, Kitamura, R, Tsuchikawa, S

Optic Express Vol. 24 ( 9 ) page： 9561-9573 2016

Combined effects of UV light and elevated temperatures on wood discolouration Reviewed

Tolvaj Laszlo, Tsuchikawa Satoru, Inagaki Tetsuya, Varga Denes

WOOD SCIENCE AND TECHNOLOGY Vol. 49 ( 6 ) page： 1225 - 1237 2015.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Wood Science and Technology

Two conifers and two deciduous wood species were irradiated by strong UV emitter mercury lamp at elevated temperatures up to 160 °C. Other series of samples were treated in the same chamber at the same temperatures but without light. Results showed that UV light irradiation produced much greater discolouration at elevated temperatures above 80 °C than at ambient temperature. The combined light irradiation and thermal treatment at 160 °C generated much larger discolouration than the sum of the discolouration data caused by UV light irradiation at 30 °C and by pure thermal treatment at 160 °C. The thermal effect during photodegradation was not only the simple addition of two effects, but the elevated temperature multiplied the effect of photodegradation. The greatest difference was shown by the redness change. The Arrhenius plots of all tree colour coordinates had a breaking point close to 100 °C, showing that above this temperature the chemical changes are more complex than below this value.

DOI： 10.1007/s00226-015-0749-1

NIR spectroscopic evaluation of nitrogen and carbon content in Japanese Mustard Spinach (Brassica rapa var. perviridis) Reviewed

Inagaki T., Minagawa C., Yokochi H., Tsuchikawa S.

2015 54th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2015 page： 97 - 99 2015.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2015 54th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2015

Demonstration of prediction of carbon and nitrogen content in Japanese Mustard Spinach (Brassica rapa var. perviridis) was accomplished using near infrared (NIR) reflectance spectroscopy. NIR reflectance spectroscopic measurement of hydroponically cultivated fresh leaves growing on stalks were taken at some growing phase. Calibrations were developed for carbon and nitrogen content in leaves using partial least square (PLS) regression method. Strong correlation between measured and predicted value for carbon and nitrogen were observed.

DOI： 10.1109/SICE.2015.7285393

A review of recent application of near infrared spectroscopy to wood science and technology Reviewed

Tsuchikawa Satoru, Kobori Hikaru

JOURNAL OF WOOD SCIENCE Vol. 61 ( 3 ) page： 213 - 220 2015.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

This review article introduces recent scientific and technical reports due to near infrared spectroscopy (NIRS) at wood science and technology, most of which was published between 2006 and 2013. Many researchers reported that NIR technique was useful to detect multi traits of chemical, physical, mechanical and anatomical properties of wood materials although it was widely used in a state where characteristic cellular structure was retained. However, we should be sensitive and careful for application of NIRS, when spectra coupled with chemometrics presents unexpected good results (especially, for mechanical physical and anatomical properties). The real application for on-line or at-line monitoring in wood industry is desired as next step. Basic spectroscopic research for wooden material is also progressed. It should be a powerful and meaningful analytical spectroscopic tool.

DOI： 10.1007/s10086-015-1467-x

Visualisation of spatial distribution of moisture content and basic density using near-infrared hyperspectral imaging method in sugi (Cryptomeria japonica)

T. Fujimoto, T. Numa, H. Kobori, S. Tsuchikawa

International Wood Products Journal Vol. 6 ( 2 ) page： 46 - 48 2015.5

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Maney Publishing

This study quantified the spatial distribution of moisture content and basic density within Cryptomeria japonica branches using near-infrared (NIR) hyperspectral imaging and multivariate data analysis techniques. The hyperspectral data for wood disk samples were acquired using a Compovision NIR Composition Imaging System (Sumitomo Electric Industries, Ltd., Yokohama, Japan) with a spectral range of 913-2519 nm. The calibration models for prediction of moisture content and basic density were developed using partial least squares (PLS) regression analysis. The PLS model for moisture content and basic density showed good predictive performance with coefficients of determination 0.82 (RMSEP512.4%) and 0.84 (RMSEP528.0 kg m&lt
sup&gt
-3&lt
/sup&gt
) respectively. The spatial distribution of predicted moisture content clearly detected the low moisture white zone surrounding the heartwood. The high density compression wood could be also visualised with the NIR hyperspectral imaging technique. The results presented here provide useful information for development of a novel log sorting method.

DOI： 10.1179/2042645314Y.0000000084

Fast online NIR technique to predict MOE and moisture content of sawn lumber Reviewed

Hikaru Kobori, Tetsuya Inagaki, Takaaki Fujimoto, Tsutomu Okura, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 69 ( 3 ) page： 329 - 335 2015.4

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

A fast online grading apparatus for sawn lumber based on near-infrared (NIR) spectroscopy has been developed. The method is based on a novel wavelength dispersive NIR spectrophotometer equipped with a diffraction grating linear sensor and high-intensity lighting. It was possible to acquire spectra from the entire surface of Hinoki cypress lumber sections traveling on a conveyor belt at a speed of 120 m min(-1). Additionally, predictive models for moisture content (MC) and modulus of elasticity (MOE) under various MC conditions were developed from the NIR spectra with the aid of partial least squares regression (PLSR) analysis. Both the MC and MOE predictive models demonstrated sufficient levels of prediction accuracy for use on high-speed conveyor belts, and the results of various experiments indicate that the developed device could be applied for the online quality certification of sawn lumber in commercial sawmills.

DOI： 10.1515/hf-2014-0021

Construction of a novel densitometer that utilizes a near-infrared laser system with Douglas fir (Pseudotsuga menziesii) Reviewed

Ryunosuke Kitamura, Satoru Tsuchikawa

Wood Material Science and Engineering Vol. 10 ( 1 ) page： 69 - 74 2015.1

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Taylor and Francis Ltd.

A novel densitometer consisting of a continuous wave near-infrared (NIR) laser source and an avalanche photodiode module as the detector has been designed, which can rapidly and non-destructively measure the density of wood. The wood density of a small area (3.14 mm2) at the radial-transverse face was continuously estimated using the intensity of the transmitted light with the aid of the modified Lambert-Beer law. By conducting a validity evaluation with statistical coefficients, it was shown that the constructed system could obtain the sharp density profile compatible with X-ray densitometer [Root mean squared error of calibration (RMSEC) = 0.045 g cm−3, Root mean squared error of validation (RMSEV) = 0.046 g cm−3). It was concluded that the constructed NIR device has high performance from the viewpoint of operability, measuring time and safety.

DOI： 10.1080/17480272.2014.968873

Assessment of variations in air-dry wood density using time-of-flight near-infrared spectroscopy Reviewed

Guillaume Hans, Ryunosuke Kitamura, Tetsuya Inagaki, Brigitte Leblon, Satoru Tsuchikawa

Wood Material Science and Engineering Vol. 10 ( 1 ) page： 57 - 68 2015.1

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Taylor and Francis Ltd.

Abstract: Non-destructive measurement of wood density using reflectance and transmittance near-infrared spectroscopy (NIRS) has already been reported by several researchers. However, these methods do not allow an independent determination of the spectral contributions of the absorption and scattering effects. In this study, time-of-flight NIRS (TOF-NIRS) was used to measure wood density of seven softwood and hardwood species. A curve fitting procedure was used to resolve the diffusion equation and compute the absorption (µa) and reduced scattering coefficients ((Formula presented.)) from the time-resolved profiles (TRPs) acquired from the wood samples. Statistical parameters were also computed from TRPs and correlated with the wood air-dry density as well as with both optical coefficients. A simple linear regression model was built to relate air-dry wood density to µa (R2 = 0.56, root mean square error [RMSE] = 0.047 g/cm3, p value &lt
0.05). Results obtained were in good agreement with the modified Beer–Lambert law for turbid media. The square root of the (Formula presented.) / (Formula presented.) ratio (which was well correlated with the photons mean path length) was used to correct for the distortion due to scattering in absorbance NIR spectra acquired using reflectance spectroscopy. This research demonstrates the potential of TOF-NIRS to assess wood density and to correct reflectance spectra for scattering effects.

DOI： 10.1080/17480272.2014.923937

Visualisation of degree of acetylation in beechwood by near infrared hyperspectral imaging Reviewed

A Review of Recent Application of Near Infrared Spectroscopy to Wood Science and Technology Invited Reviewed

Tsuchikawa, S.; Kobori, H.

Journal of Wood Science Vol. 61 page： 213-230 2015

Determination of optical parameters and moisture content of wood with visible-NIR spectroscopy Reviewed

Haddadi, A; Hans, G.; Leblon, B.; Pirouz, Z.; Tsuchikawa, S.; Nader, J.; and Groves, K.

Journal of Near Infrared Spectroscopy 2015

Combined effects of UV light and elevated temperatures on wood discolouration Reviewed

Tolvaj, L.; Tsuchikawa, S.; Inagaki T.; Varga, D.

Wood Science and Technology Vol. 49 ( 6 ) page： 1225-1237 2015

A Review of Recent Application of Near Infrared Spectroscopy to Wood Science and Technology

Tsuchikawa, S, Kobori, H

Journal of Wood Science Vol. 61 page： 213-230 2015

Combined effects of UV light and elevated temperatures on wood discolouration

Tolvaj, L, Tsuchikawa, S, Inagaki T, Varga, D

Wood Science and Technology Vol. 49 ( 6 ) page： 1225-1237 2015

NIR spectroscopic evaluation of nitrogen and carbon content in Japanese Mustard Spinach (Brassica rapa var. perviridis) Reviewed

Inagaki Tetsuya, Minagawa Chinatsu, Yokochi Hideyuki, Tsuchikawa Satoru

2015 54TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) page： 97 - 99 2015

Tetsuya Inagaki, Katsuya Mitsui, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 23 ( 6 ) page： 353 - 360 2015

Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

Spatial distributions of the degree of acetylation in cross- and radial-sectional faces of beechwood samples under vapour-phase reaction are observed using near infrared hyperspectral imaging. The near infrared second derivative amplitude at 1727 nm, which is assigned to the first overtone of the CH stretching vibration averaged over the cross section and radial section, has strong linear correlation-with the substance concentration of acetyl groups (CA) held in the cell walls. Tangentially averaged CA is well explained by the modified rate equation. Both the rate constant and hindrance to the diffusion reagent reach constant values at a depth of about 4 mm from the edge of the wood, indicating that the acetylation reaction proceeds close to a depth of 4 mm.

DOI： 10.1255/jnirs.1181

NIR spectroscopic evaluation of nitrogen and carbon content in Japanese Mustard Spinach (Brassica rapa var. perviridis) Reviewed

Tetsuya Inagaki, Chinatsu Minagawa, Hideyuki Yokochi, Satoru Tsuchikawa

2015 54TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) page： 97 - 99 2015

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy Reviewed

Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy

Inagaki, T.; Ahmed, B.; Hartley, I. D.; Tsuchikawa, S.; Reid, M.

Journal of Infrared, Millimeter, and Terahertz Waves Vol. 35 ( 11 ) page： 949-961 2014.11

Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy

Inagaki, T, Ahmed, B, Hartley, I. D, Tsuchikawa, S, Reid, M

Journal of Infrared, Millimeter, and Terahertz Waves Vol. 35 ( 11 ) page： 949-961 2014.11

Inagaki Tetsuya, Ahmed Belal, Hartley Ian D., Tsuchikawa Satoru, Reid Matthew

JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES Vol. 35 ( 11 ) page： 949 - 961 2014.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Infrared, Millimeter, and Terahertz Waves

In this study, demonstration of simultaneous prediction of solid wood density and moisture content, both of which are critical in manufacturing operations, of 4 species (Aspen, Birch, Hemlock and Maple) was accomplished using terahertz time-domain spectroscopy (THz-TDS). THz measurements of wood at various moisture contents were taken for two orientations of the THz field (parallel and perpendicular) with respect to the visible grain. The real and imaginary parts of the dielectric function averaged over the frequency range of 0.1 to 0.2 THz had strong correlation with density and moisture content of the wood. We extend a model that has been applied previously to oven-dry wood to include the effects of moisture below the fiber saturation point by combining two effective medium models, which allows the dielectric function of water, air and oven-dry cell wall material to be modeled to give an effective dielectric function for the wood. A strong correlation between measured and predicted values for density and moisture content were observed.

DOI： 10.1007/s10762-014-0095-7

Prediction of oven-dry density of wood by time-domain terahertz spectroscopy Reviewed

Tetsuya Inagaki, Ian D. Hartley, Satoru Tsuchikawa, Matthew Reid

HOLZFORSCHUNG Vol. 68 ( 1 ) page： 61 - 68 2014.1

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

Wood is relatively transparent to terahertz (THz) radiation with wavelengths in the submillimeter range. This radiation has a high potential for sensing and imaging wood with a good spatial resolution. THz is especially sensitive to moisture content, fiber alignment, and density - all of which are critical in the manufacturing of wood products. In this work, a systematic study was undertaken on 46 very different wood species by means of THz time-domain spectroscopy with density determination in focus. The dielectric response of wood was modeled based on the Maxwell-Garnett effective medium theory. The dielectric function of the cell wall material was found to be extremely consistent over this large number of species with very different properties. This renders possible to determine wood density by THz time-domain spectroscopy. A strong correlation between the measured and predicted densities has been observed for all the samples investigated.

DOI： 10.1515/hf-2013-0013

Mapping of Leaf Water Content Using Near-Infrared Hyperspectral Imaging Reviewed

Higa Sakura, Kobori Hikaru, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 67 ( 11 ) page： 1302 - 1307 2013.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

In this study, near-infrared hyperspectral imaging was applied to predict the water content of golden pothos (Epipremnum aureum) leaves, after which partial least squares regression (PLSR) analysis was performed to predict their averaged water content. The resulting predictive model was then applied to each single-pixel spectra in order to construct a water content image that could be used to evaluate the model's applicability to the single-pixel spectra through partial least squares score comparisons between the averaged spectra used for calibration and the single-pixel spectra. In the next phase, it was determined that a rebuilt PLSR predictive model based on the averaged spectra of an applicable pixel showed higher prediction accuracy than that of the original model. This study provides effective information about the limitations of prediction mapping and the optimization of pixel selections for better calibrations. © 2013 Society for Applied Spectroscopy.

DOI： 10.1366/13-07028

A Review of Recent Near-Infrared Research for Wood and Paper (Part 2) Reviewed

Tsuchikawa Satoru, Schwanninger Manfred

APPLIED SPECTROSCOPY REVIEWS Vol. 48 ( 7 ) page： 560 - 587 2013.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy Reviews

This review article introduces recent technical and scientific reports on near-infrared (NIR) spectroscopy in the wood and paper industry, which have increased during the last decade. Many researchers have reported that the NIR technique is useful for detection of both chemical and physical properties of wood materials and has been widely used in cases where the characteristic cellular structure of the material is retained. With regard to application of NIR spectroscopy to pulp and paper, many publications have reported its potential as an on-line measurement technique during paper-making process control. NIR spectroscopy is considered fundamental in applied research on wood and paper. Utilization of NIR spectroscopy in the wood and paper industry should take into account its applicability and limitations as a nondestructive technique. © 2013 Copyright Taylor and Francis Group, LLC.

DOI： 10.1080/05704928.2011.621079

Prediction of dry veneer stiffness using near infrared spectra from transverse section of green log Reviewed Open Access

Takaaki Fujimoto, Keisuke Kawakami, Haruhisa Aimi, Jun-ichi Shimizu, Koichi Hasegawa, Hikaru Kobori, Satoru Tsuchikawa

Journal of Wood Science Vol. 59 ( 5 ) page： 383 - 388 2013.10

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This study examined the feasibility of near infrared spectroscopy as a novel technique for log assessment on the basis of wood property. Near infrared (NIR) spectra were obtained from the transverse section of green log and multivariate regression analysis was carried out to predict the stiffness of veneer processed from the log. The stiffness of the veneer was dynamic modulus of elasticity measured using ultrasonic method. The calibrations of veneer stiffness had moderate relationships between measured and NIR-predicted values, with regression coefficients ranging from 0.84 to 0.88. The calibration equations were applied to the test set and it was found that predictions were also well fitted, with regression coefficients ranging from 0.67 to 0.89. The results indicate that the variation of wood stiffness within the logs could be assessed using the NIR spectra from the cross-section of logs. The spectra were obtained from green condition of the log and the stiffness of veneer was measured after kiln drying. Thus, the results imply that the wood stiffness in dry condition could be predicted using the spectra collected from green logs. If the models obtained in this study put into the imaging system, the two-dimensional map of the stiffness would be visualized on the cross-section of logs. The NIR spectroscopy coupled with imaging system could compensate the weak point of the traditional methods for log assessment. © 2013 The Japan Wood Research Society.

DOI： 10.1007/s10086-013-1352-4

Time-Resolved Principal Component Imaging Analysis of Chlorophyll Fluorescence Induction for Monitoring Leaf Water Stress Reviewed

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon, B; Tsuchikawa, S

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013.9

Near-infrared spectroscopy and the forest products industry Reviewed Open Access

Leblon B., Tsuchikawa S.

Forestry Chronicle Vol. 89 ( 5 ) page： 575 - 576 2013.9

Near-Infrared Spectroscopy and the Forest Products Industry

Brigitte Leblon, Satoru Tsuchikawa

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 575 2013.9

Kobori Hikaru, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 67 ( 6 ) page： 594 - 599 2013.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Chlorophyll fluorescence induction is widely applied to investigate plant growth conditions by calculating the ratio of its intensity at oxidized and reduced states. We examined the applicability of a time-resolved profile of chlorophyll fluorescence induction with the aid of multivariate analysis to monitor the leaf water stress. Principal component (PC) analysis of timeresolved images of chlorophyll fluorescence induction and their score images were reconstructed. Control leaves (non-stressed leaves) and water-stressed leaves could be classified by normalized PC3 score images. This technique has the potential to monitor the water stress condition of plants by using a simple device. © 2013 Society for Applied Spectroscopy.

DOI： 10.1366/12-06850

Time-of-flight Near-infrared Spectroscopy for Nondestructive Measurement of Internal Quality in Grapefruit Reviewed

Yohei Kurata, Tomoe Tsuchida, Satoru Tsuchikawa

JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE Vol. 138 ( 3 ) page： 225 - 228 2013.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC HORTICULTURAL SCIENCE

We proposed a technique combining time-of-flight (TOF) and near-infrared spectroscopy (NIRS), termed TOF-NIRS, capable of measuring the time-resolved profiles of near-infrared (NIR) light with nanosecond resolution. Analysis of the variation in time-resolved profiles was used to estimate soluble solids concentration (SSC) and acidity in grapefruit (Citrus paradisi), and the prediction accuracy was compared with the conventional NIR measurement device. In data processing, the cross-correlation function, which evaluated the similarity between the reference and transmitted beams, was introduced as an explanatory variable for partial least squares regression. TOF-NIRS predicted both SSC and acidity in grapefruit with higher precision than the conventional NIR measurement with respective r values of 0.72 and 0.85. Specifically, the superiority of TOF-NIRS was attributed to measurement time and prediction accuracy in determining acidity.

Time-of-flight near-infrared spectroscopy for nondestructive measurement of internal quality in grapefruit Reviewed

Kurata Y., Tsuchida T., Tsuchikawa S.

Journal of the American Society for Horticultural Science Vol. 138 ( 3 ) page： 225 - 228 2013.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of the American Society for Horticultural Science

We proposed a technique combining time-of-flight (TOF) and near-infrared spectroscopy (NIRS), termed TOF-NIRS, capable of measuring the time-resolved profiles of near-infrared (NIR) light with nanosecond resolution. Analysis of the variation in time-resolved profiles was used to estimate soluble solids concentration (SSC) and acidity in grapefruit (Citrus paradisi)*and the prediction accuracy was compared with the conventional NIR measurement device. In data processing*the cross-correlation function*which evaluated the similarity between the reference and transmitted beams*was introduced as an explanatory variable for partial least squares regression. TOF-NIRS predicted both SSC and acidity in grapefruit with higher precision than the conventional NIR measurement with respective r values of 0.72 and 0.85. Specifically*the superiority of TOF-NIRS was attributed to measurement time and prediction accuracy in determining acidity.

DOI： 10.21273/jashs.138.3.225

Applicability of Vis-NIR hyperspectral imaging for monitoring wood moisture content (MC) Reviewed

Time-of-flight Near-infrared Spectroscopy for Nondestructive Measurement of Internal Quality in Grapefruit

Kurata Yohei, Tsuchida Tomoe, Tsuchikawa Satoru

JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE Vol. 138 ( 3 ) page： 225 - 228 2013.5

Hikaru Kobori, Nathalie Gorretta, Gilles Rabatel, Veronique Bellon-Maurel, Gilles Chaix, Jean-Michel Roger, Satoru Tsuchikawa

HOLZFORSCHUNG Vol. 67 ( 3 ) page： 307 - 314 2013.4

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER & CO

Visible-near-infrared hyperspectral imaging was tested for its suitability for monitoring the moisture content (MC) of wood samples during natural drying. Partial least-squares regression (PLSR) prediction of MC was performed on the basis of average reflectance spectra obtained from hyperspectral images. The validation showed high prediction accuracy. The results were compared concerning the PLSR prediction of MC mapping from raw spectra and standard normal variate (SNV) treatment. SNV pretreatment leads to the best results for visualizing the MC distribution in wood. Hyperspectral imaging has a high potential for monitoring the water distribution of wood.

DOI： 10.1515/hf-2012-0054

High accuracy rapid prediction and feasibility of on-site nondestructive estimation of Para rubber quality by spectroscopic methods Reviewed

Inagaki Tetsuya, Sirisomboon Panmanas, Liu Chang, Thanapase Warunee, Tsuchikawa Satoru

JOURNAL OF WOOD SCIENCE Vol. 59 ( 2 ) page： 119 - 126 2013.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

The aim of this study was to investigate convenient spectroscopic evaluation method of Para rubber quality. Ultra violet-near infrared (UV-NIR 370-1085 nm) spectra of latex were measured in transmittance mode. Calibrations for total solid content (TSC) and dry rubber content (DRC) were developed using spectral data set with aid of partial least square regression analysis using 57 samples. UV-NIR spectra of latex provided good regression models between measured and predicted values of TSC and DRC with determination coefficient for cross-validation of 0. 96 and 0. 97, respectively. The ranks were 2 and 1, respectively. This study suggests high accuracy in-line quality control of latex using UV-NIR spectroscopy. The long wavelength NIR spectra of bark were scanned to check the feasibility of on-site evaluation of latex quality by measuring the NIR spectra of standing tree. From the observation of near infrared spectra, it was shown that there was more latex signal in outer part of wood bark than in inner part of wood bark. This result suggests that the focal point should be on the outer part of bark to get the signal of latex when we measure the spectra of standing tree. © 2012 The Japan Wood Research Society.

DOI： 10.1007/s10086-012-1305-3

High accuracy rapid prediction and feasibility of on-site nondestructive estimation of Para rubber quality by spectroscopic method Reviewed

Inagaki, T.; Sirisomboon, P.; Liu, C.; Thanapase, W.; Tsuchikawa, S.

Journal of Wood Science Vol. 59 page： 119-126 2013

Applicability of Vis-NIR hyperspectral imaging for monitoring wood moisture content (MC) Reviewed

Kobori, H.; Gorretta, N.; Rabatel, G.; Bellon-Maurel, V.; Chaix, G.; Roger, J.-M.; Tsuchikawa, S.

Holzforschung Vol. 67 ( 3 ) page： 307-314 2013

Establishment of near infrared archaeometry Invited Reviewed

Inagaki, T.; Tsuchikawa, S.

NIR News Vol. 24 ( 7 ) page： 4-6 2013

Mapping of Leaf Water Content Using Near-Infrared Hyperspectral Imaging", Applied Spectroscopy Reviewed

Higa, S.; Kobori, H.; Tsuchikawa, S.

Applied Spectroscopy Vol. 67 ( 11 ) page： 1302-1307 2013

A review of near-infrared spectroscopy for monitoring moisture content and density of solid wood Reviewed

Leblon, B.; Adedipe, O.; Hans, G.; Haddadi1, A.; Tsuchikawa, S.; Burger; J.; Stirling, R; Pirouz, Z.; Groves, K.; Nader, J.; LaRocque, A.

The Forestry Chronicle Vol. 89 ( 5 ) page： 595-606 2013

Vis-NIR Spectroscopy for the On-site Prediction of Wood Properties Reviewed

Kobori, H.; Kojima, M.; Yamamoto, H.; Sasaki, Y.; Yamaji, F. M.; Tsuchikawa, S.

The Forestry Chronicle Vol. 89 ( 5 ) page： 36-43 2013

Time-Resolved Principal Component Imaging Analysis of Chlorophyll Fluorescence Induction for Monitoring Leaf Water Stress Reviewed

Kobori, H.; Tsuchikawa, S.

Applied Spectroscopy Vol. 67 ( 6 ) page： 594-599 2013

A Review of Recent Near Infrared Research for Wood and Paper Part 2 Invited Reviewed

Tsuchikawa, S.; Schwanninger, S.

Applied Spectroscopy Review Vol. 48 page： 560-587 2013

Time of Flight Near Infrared Spectroscopy for Nondestructive Measurement of internal quality in Grapefruit Reviewed

Kurata, Y.; Tsuchida, T.; Tsuchikawa, S.

Journal of American Society of Horticultural Science Vol. 138 page： 225-228 2013

Prediction of wood density using near infrared-based partial least squares regression models calibrated with X-ray microdensity

Rodrigues, J. C.; Fujimoto, T.; Schwanninger, M.; Tsuchikawa, S.

NIR News Vol. 24 ( 2 ) page： 4-5,8 2013

Time-Resolved Principal Component Imaging Analysis of Chlorophyll Fluorescence Induction for Monitoring Leaf Water Stress

Kobori, H, Tsuchikawa, S

Applied Spectroscopy Vol. 67 ( 6 ) page： 594-599 2013

Vis-NIR spectroscopy for the on-site prediction of wood properties Reviewed

Kobori Hikaru, Kojima Miho, Yamamoto Hiroyuki, Sasaki Yasutoshi, Yamaji Fabio Minoru, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 631 - 638 2013

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Forestry Chronicle

We investigated the feasibility of visible-near-infrared (Vis-NIR) spectroscopy for estimation of wood qualities of fast-growing Eucalyptus grandis. Partial least squares regression (PLSR) models are applied to predict the diameter at the breast height (DBH), lateral growth rate (LGR) and propagation velocity of stress waves (PVSW). It was possible to estimate LGR and PVSW with appropriate accuracy. This suggested that perhaps information in terms of maturation is included in Vis-NIR spectra. The key factors in the validation of PVSW and LGR were the water and cellulose condition in wood.

DOI： 10.5558/tfc2013-114

A review of near-infrared spectroscopy for monitoring moisture content and density of solid wood Reviewed

Vis-NIR Spectroscopy for the On-site Prediction of Wood Properties

Kobori, H, Kojima, M, Yamamoto, H, Sasaki, Y, Yamaji, F. M, Tsuchikawa, S

The Forestry Chronicle Vol. 89 ( 5 ) page： 36-43 2013

A review of near-infrared spectroscopy for monitoring moisture content and density of solid wood

Leblon, B, Adedipe, O, Hans, G, Haddadi1, A, Tsuchikawa, S, Burger; J, Stirling, R, Pirouz, Z, Groves, K, Nader, J, LaRocque, A

The Forestry Chronicle Vol. 89 ( 5 ) page： 595-606 2013

Applicability of Vis-NIR hyperspectral imaging for monitoring wood moisture content (MC)

Kobori, H, Gorretta, N, Rabatel, G, Bellon-Maurel, V, Chaix, G, Roger, J.-M, Tsuchikawa, S

Holzforschung Vol. 67 ( 3 ) page： 307-314 2013

A Review of Recent Near Infrared Research for Wood and Paper Part 2

Tsuchikawa, S, Schwanninger, S

Applied Spectroscopy Review Vol. 48 page： 560-587 2013

Leblon Brigitte, Adedipe Oluwatosin, Hans Guillaume, Haddadi Ataollah, Tsuchikawa Satoru, Burger James, Stirling Rod, Pirouz Zarin, Groves Kevin, Nader Joseph, LaRocque Armand

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 595 - 606 2013

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Forestry Chronicle

This review article examines past and current research on the application of near-infrared (NIR) reflectance/transmittance spectroscopy (NIRS) for real-time monitoring of moisture content and density of solid wood Most of the applications of NIRS on solid wood have focussed on the application of multivariate statistics as exploratory tools for the prediction of physical, chemical and mechanical properties, such as moisture content, density, stiffness, cellulose and lignin content. However, very few studies on the development of optical models and the use of NIRS transmittance techniques on solid wood have been reported. NIRS technology has the potential to be used as a rapid tool that could be employed for at-line measurement and monitoring of wood properties in the forest products industry.

DOI： 10.5558/tfc2013-111

Rapid Prediction of Past Climate Condition from Lake Sediments by Near-Infrared (NIR) Spectroscopy Reviewed

Establishment of near infrared archaeometry Invited Reviewed

Inagaki, T, Tsuchikawa, S

NIR News Vol. 24 ( 7 ) page： 4-6 2013

Near-Infrared Spectroscopy and the Forest Products Industry Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 575 2013

Mapping of Leaf Water Content Using Near-Infrared Hyperspectral Imaging", Applied Spectroscopy

Higa, S, Kobori, H, Tsuchikawa, S

Applied Spectroscopy Vol. 67 ( 11 ) page： 1302-1307 2013

High accuracy rapid prediction and feasibility of on-site nondestructive estimation of Para rubber quality by spectroscopic method

Inagaki, T, Sirisomboon, P, Liu, C, Thanapase, W, Tsuchikawa, S

Journal of Wood Science Vol. 59 page： 119-126 2013

Prediction of wood density using near infrared-based partial least squares regression models calibrated with X-ray microdensity Reviewed

Rodrigues, J. C, Fujimoto, T, Schwanninger, M, Tsuchikawa, S

NIR News Vol. 24 ( 2 ) page： 4-5,8 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

Time-of-flight Near-infrared Spectroscopy for Nondestructive Measurement of Internal Quality in Grapefruit Reviewed

土川覚

Vol. 138(3) page： 1 - 4 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed Open Access

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

La spectroscopie proche infrarouge et le secteur des produits forestiers Reviewed

Leblon Brigitte, Tsuchikawa Satoru

FORESTRY CHRONICLE Vol. 89 ( 5 ) page： 575 - 576 2013

Inagaki Tetsuya, Shinozuka Yoshitsugu, Yamada Kazuyoshi, Yonenobu Hitoshi, Hayashida Akira, Tsuchikawa Satoru, Yoshida Akihiro, Hoshino Yasuharu, Gotanda Katsuya, Yasuda Yoshinori

APPLIED SPECTROSCOPY Vol. 66 ( 6 ) page： 673 - 679 2012.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

This study explored the feasibility of rapid, nondestructive near-infrared (NIR) reflection spectroscopy for the prediction of conventional physical properties, carbon-nitrogen-sulfur (CNS) analysis, and concentration of inorganic components in sediment cores from a brackish lake. A long core sample, which consisted of well-preserved annually formed lamina from Lake Ogawara along the Pacific coast in Aomori Prefecture, northeastern Japan, was used to investigate the past environmental record. The core was previously analyzed for physical properties, CNS, and inorganic components. Calibration models were developed from NIR reflection spectra of 149 core samples. Partial least squares (PLS) analysis provided good regression models between measured and predicted values for water content, total nitrogen (TN), total organic carbon (TOC), total sulfur (TS), Al 2O 3, S/Al 2O 3, Fe 2O 3/Al 2O 3, Sc/Al 2O 3, Cu/Al 2O 3, and Zn/Al 2O 3 with coefficients of determination (r 2) for cross-validation of 0.73, 0.89, 0.88, 0.73, 0.92, 0.81, 0.82, 0.75, 0.82, and 0.82, respectively. The variation of predicted component values as a function of depth showed the same trend as that of conventionally measured values. This study also showed the possibility of NIR spectroscopy as an on-site, rapid analytical tool for the identification of tephra (fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism), which is important for dating. © 2012 Society for Applied Spectroscopy.

DOI： 10.1366/11-06418

Eucalyptus camaldulensis density and fiber length estimated by near-infrared spectroscopy Reviewed

リグナ・ハノーバー2011名古屋大学ブース出展報告

土川覚

木材工業 = Wood industry Vol. 67 ( 2 ) page： 81 - 84 2012.2

リグナ・ハノーバー2011名古屋大学ブース出展報告 Reviewed

土川覚

木材工業 = Wood industry Vol. 67 ( 2 ) page： 81 - 84 2012.2

Inagaki Tetsuya, Schwanninger Manfred, Kato Reina, Kurata Yohei, Thanapase Warunee, Puthson Pratuang, Tsuchikawa Satoru

WOOD SCIENCE AND TECHNOLOGY Vol. 46 ( 1-3 ) page： 143 - 155 2012.1

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Wood Science and Technology

Density and fiber length belong to the parameters that are used by the pulping industry as indicators of wood quality for different industrial processes and final paper products. The feasibility of Fourier transform near-infrared (FT-NIR) spectroscopy for the non-destructive evaluation of fiber length and air-dry density of fast-growing E. camaldulensis from Thailand was investigated using 50 samples. NIR spectra taken from solid wood and air-dry density as well as fiber length were used for partial least squares (PLS) regression analyses. It is the first time that the fiber length of E. camaldulensis solid wood could be predicted with high accuracy and precision and that the ratios of performance to deviation (RPD) obtained are the first that fully fulfill the requirements of AACC Method 39-00 (AACC 1999) for screening in breeding programs (RPD ≥ 2.5). The RPDs for cross-validation (test set validation) of the NIR-PLS-R models of 3.3 (3.8) for air-dry density and 3.5 (3.9) for fiber length allow drawing the conclusion that the models are at least applicable for screening in breeding programs as they lie in-between screening (RPD ≥ 2.5) and quality control (RPD ≥ 5). Even when 40% of the samples were removed in cross-validation of the air-dry density model, the RPD is 3.2, which confirms that the model is robust, stable, and well qualified for prediction. The good model statistics obtained in this study might be due to the fact that measurement sites for the measurement of NIR spectra, air-dry density, and fiber lengths were strictly coincided. © 2010 Springer-Verlag.

DOI： 10.1007/s00226-010-0379-6

Prediction of wood density independently of moisture conditions using near infrared spectroscopy Reviewed

リグナ・ハノーバー２０１１名古屋大学ブース出展報告 Invited Reviewed

土川　覚

木材工業 Vol. 67 ( 2 ) page： 81-84 2012

広帯域分光方式による革新的な木材多形質高速非破壊測定装置の開発 Invited

土川　覚

Techno Innovation Vol. 84 page： 19-23 2012

Prediction of wood density independent of moisture conditions using near infrared spectroscopy

Fujimoto, T.; Kobori, H.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 20 ( 3 ) page： 353-359 2012

Rapid prediction of past climate condition from lake sediments by NIR spectroscopy Reviewed

Inagaki, T.; Shinozuka, Y.; Yamada, K.; Yonenobu, H.; Tsuchikawa, S.; Yoshida, A.; Hoshino, Y.; Gotanda, K.; Yasuda, Y.

Applied Spectroscopy Vol. 66 ( 6 ) page： 673-679 2012

Eucalyptus camaldulensis density and fiber length estimated by near infrared spectroscopy Reviewed

Inagaki, T.; Schwanninger, S.; Kato, R.; Kurata1, Y.; Thanapase, W.; Puthson, P.; Tsuchikawa, S.

Wood Science and Technology Vol. 46 page： 143-155 2012

リグナ・ハノーバー２０１１名古屋大学ブース出展報告

土川覚

木材工業 Vol. 67 ( 2 ) page： 81-84 2012

広帯域分光方式による革新的な木材多形質高速非破壊測定装置の開発

土川覚

Techno Innovation Vol. 84 page： 19-23 2012

Eucalyptus camaldulensis density and fiber length estimated by near infrared spectroscopy

Inagaki, T, Schwanninger, S, Kato, R, Kurata1, Y, Thanapase, W, Puthson, P, Tsuchikawa, S

Wood Science and Technology Vol. 46 page： 143-155 2012

Prediction of wood density independent of moisture conditions using near infrared spectroscopy

Fujimoto, T, Kobori, H, Tsuchikawa, S

Journal of Near Infrared Spectroscopy Vol. 20 ( 3 ) page： 353-359 2012

Rapid prediction of past climate condition from lake sediments by NIR spectroscopy

Inagaki, T, Shinozuka, Y, Yamada, K, Yonenobu, H, Tsuchikawa, S, Yoshida, A, Hoshino, Y, Gotanda, K, Yasuda, Y

Applied Spectroscopy Vol. 66 ( 6 ) page： 673-679 2012

Fujimoto Takaaki, Kobori Hikaru, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 20 ( 3 ) page： 353 - 359 2012

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

Near infrared (NIR) spectra obtained from 100 Japanese larch (Larix kaempferi) wood samples containing various amounts of moisture were used to examine the effect of moisture conditions on the accuracy of predicting wood density. Partial least squares regression (PLS-R) analysis was performed to predict wood density under air dry (DEN-ar), water impregnated (DEN-wi) and oven dry (DEN-ov) conditions. The NIR spectra varied with the moisture conditions of the wood, where the characteristic absorbance bands in the vicinity of 7320 cm-1 (1366 nm), 7160 cm-1 (1400 nm) and 7000 cm -1 (1428 nm) were related to cellulose and water. The spectral differences between high- and low-density samples varied depending on the moisture conditions; high-density samples showed low absorbance values at 7160 cm-1 when wet and showed high absorbance values at 7320 cm -1 and 7000 cm-1 when dry. DEN-ar, DEN-wi and DEN-ov could be predicted using spectra collected from the corresponding moisture conditions [coefficient of determination (R2) = 0.79-0.89; standard error of prediction (SEP) = 24-26 kg m-3]. Prediction of DEN-ar and DEN-ov could also be achieved using spectra collected from various moisture conditions (R2 = 0.86-0.87, SEP = 22 kg m-3). The loadings from PLS-R analysis indicated that the absorption bands in the vicinity of 7320 cm -1, 7160 cm-1 and 7000 cm-1 played an important role in predicting wood density. NIR spectroscopy has the potential to predict wood density independently of the moisture content of the sample. © 2012 IM Publications LLP. All rights reserved.

DOI： 10.1255/jnirs.994

Nondestructive Measurement of Wooden Materials by Near Infrared Spectroscopy : Present Conditions and Prospects Reviewed

Nondestructive Measurement of Wooden Materials by Near Infrared Spectroscopy : Present Conditions and Prospects

TSUCHIKAWA Satoru

Wood industry Vol. 66 ( 10 ) page： 430 - 435 2011.10

Nondestructive Measurement of Wooden Materials by Near Infrared Spectroscopy : Present Conditions and Prospects Invited Reviewed

TSUCHIKAWA Satoru

Wood industry Vol. 66 ( 10 ) page： 430 - 435 2011.10

TSUCHIKAWA Satoru

Wood industry Vol. 66 ( 10 ) page： 430 - 435 2011.10

Optical characteristics of wood investigated by time-of-flight near infrared spectroscopy Reviewed

Kurata Yohei, Fujimoto Takaaki, Tsuchikawa Satoru

HOLZFORSCHUNG Vol. 65 ( 3 ) page： 389 - 395 2011.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Holzforschung

A new optical measurement system, the main components of which are a diode-pumped solid state laser and avalanche photodiodes, was introduced to clarify the optical characteristics of wood from the viewpoint of time-of-flight near infrared spectroscopy. The sample thickness and the wavelength of input pulsed laser clearly influenced the transmitted time-resolved profile. The effective optical path length became 15 times longer than the sample thickness. The optical model based on the diffusion approximation to the radiative transfer equation proved to be useful for thick samples, which can be optically regarded as an ideal diffuser, although wood is a structural material with non-homogeneous cellular structure. © 2011 by Walter de Gruyter Berlin New York.

DOI： 10.1515/HF.2011.034

Feasibility of near-infrared spectroscopy for online multiple trait assessment of sawn lumber Reviewed

Optical characteristics of wood investigated by time-of-flight near infrared spectroscopy Reviewed

Kurata, Y., Fujimoto, T., Tsuchikawa S.

Holzforschung Vol. 65 page： 389-395 2011

近赤外分光法による木質材料の非破壊計測　－現状と展望－ Invited Reviewed

土川　覚

木材工業 Vol. 66 ( 10 ) page： 430-435 2011

Application of NIR spectroscopy to wood products

Tsuchikawa S.; Fujimoto, T.

Proceedings of 17th International Nondestructive Testing and Evaluation of Wood Symposium page： 665-671 2011

Application of NIR spectroscopy to wood products

Tsuchikawa S, Fujimoto, T

Proceedings of 17th International Nondestructive Testing and Evaluation of Wood Symposium page： 665-671 2011

Optical characteristics of wood investigated by time-of-flight near infrared spectroscopy

Kurata, Y, Fujimoto, T, Tsuchikawa S

Holzforschung Vol. 65 page： 389-395 2011

Application of NIR spectroscopy to wood products

Tsuchikawa S, Fujimoto, T

Proceedings of 17th International Nondestructive Testing and Evaluation of Wood Symposium page： 665-671 2011

Application of NIR spectroscopy to wood products

Tsuchikawa S., Fujimoto, T.

Proceedings of 17th International Nondestructive Testing and Evaluation of Wood Symposium page： 665-671 2011

Feasibility of near-infrared spectroscopy for online multiple trait assessment of sawn lumber

Fujimoto Takaaki, Kurata Yohei, Matsumoto Kazushige, TSUCHIKAWA Satoru

Journal of wood science Vol. 56 ( 6 ) page： 452 - 459 2010.12

FUJIMOTO Takaaki, KURATA Yohei, MATSUMOTO Kazushige, TSUCHIKAWA Satoru

Journal of wood science Vol. 56 ( 6 ) page： 452 - 459 2010.12

Feasibility of near-infrared spectroscopy for online multiple trait assessment of sawn lumber Reviewed

Fujimoto Takaaki, Kurata Yohei, Matsumoto Kazushige, Tsuchikawa Satoru

JOURNAL OF WOOD SCIENCE Vol. 56 ( 6 ) page： 452 - 459 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

Near-infrared (NIR) spectroscopy coupled with multivariate analysis was applied to estimate multiple traits of sawn lumber. The effects of the lumber conveying speed (LCS) and measurement resolution of spectra (MRS) on the calibrations were examined. NIR spectra ranging from 1300 to 2300 nm were acquired at LCSs of 10, 20, and 30 m/min and at MRSs of 2, 4, and 16 nm. Prediction models of bending strength (Fb), modulus of elasticity in bending tests (Eb), dynamic modulus of elasticity (Efr), and wood density (DEN) were developed using partial least-squares (PLS) analysis. LCS and MRS did not significantly influence the calibration performance for any wood property. The regression coefficients also showed no clear differences for any of the conditions. This indicates that the important explanatory variables included in the models are not greatly influenced by these measurement conditions. PLS2 analysis results, when presented graphically, allowed easy interpretation of the relationships between wood mechanical properties and chemical components, e. g., bending strength and stiffness were mainly related to polysaccharides cellulose and hemicellulose. NIR spectroscopy has considerable potential for online grading of sawn lumber, despite the harsh measurement conditions. © 2010 The Japan Wood Research Society.

DOI： 10.1007/s10086-010-1122-5

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T., Matsumoto K., Kurata Y., Tsuchikawa S.

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Near-infrared (NIR) spectroscopy, coupled with multivariate analysis, has been used to predict the wood properties of sawn lumber, whose diffuse reflection spectra were acquired under moving conditions (30 m/min). Models predicting for bending strength (Fb), modulus of elasticity in bending (Eb), dynamic modulus of elasticity (Efr), air-dried wood density (DEN), and moisture content (MC) were developed using the partial least squares (PLS) analysis. For all wood properties, calibration models showed relative strong relationships between laboratory-measured and NIR-predicted values with coefficients of determination ranging from 0.55 to 0.80. The vector of regression coefficient revealed the important explanatory variables included in each model. It was concluded that NIR spectroscopy could be applied to on-line grading of lumber quality.

Difference of the Crystal Structure of Cellulose in Wood after Hydrothermal and Aging Degradation: A NIR Spectroscopy and XRD Study Reviewed

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T., Matsumoto K., Kurata Y., Tsuchikawa S.

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Enhanced on-line stress grading of sawn lumber using near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

11th World Conference on Timber Engineering 2010, WCTE 2010 Vol. 2 page： 1538 - 1542 2010.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：11th World Conference on Timber Engineering 2010, WCTE 2010

Inagaki Tetsuya, Siesler Heinz W., Mitsui Katsuya, Tsuchikawa Satoru

BIOMACROMOLECULES Vol. 11 ( 9 ) page： 2300 - 2305 2010.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Biomacromolecules

The change of crystalline structure in hydrothermally treated hinoki wood was investigated by means of Fourier-transform near-infrared spectroscopy in combination with a deuterium exchange method and X-ray diffraction. The results were compared with analogous data of dry-exposed archeological wood taken from an old wooden temple. Although the decomposition of the amorphous regions in cellulose and hemicelluloses, which corresponds to an increase of the degree of crystallinity, was observed for both, archeologically and hydrothermally treated wood, the increase of crystallite thickness was confirmed only for hydrothermally treated wood. The increase of the average size of crystallites corresponds well to the measured decrease of the deuteration accessibility of the crystalline regions. As the accessibility of the crystalline regions decreased for both, D2O and t-butanol, it is assumed that due to the expansion of the crystalline domains by hydrothermal treatment several elementary fibrils are arranged at distances below 0.3 nm. © 2010 American Chemical Society.

DOI： 10.1021/bm100403y

Effect of Crosscutting Crooked Sugi (Cryptomeria japonica) Logs on Sawing Yield and Quality of Sawn Lumber Reviewed

Ikami Y., Matsumura Y., Murata K., Tsuchikawa S.

FOREST PRODUCTS JOURNAL Vol. 60 ( 3 ) page： 244 - 248 2010.5

Effect of Crosscutting Crooked Sugi (Cryptomeria japonica) Logs on Sawing Yield and Quality of Sawn Lumber Reviewed

Y. Ikami, Y. Matsumura, K. Murata, S. Tsuchikawa

FOREST PRODUCTS JOURNAL Vol. 60 ( 3 ) page： 244 - 248 2010.5

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：FOREST PRODUCTS SOC

The objective of this study was to develop an efficient method for using crooked sugi (Cryptomeria japonica D. Don) logs by crosscutting the logs prior to sawing. We investigated the effect of crosscutting crooked logs on the sawing yield and the quality of sawn lumber and proposed an effective processing method. The sawing yield and the quality of sawn lumber were improved by crosscutting the logs one time. An economic analysis based on the processing intensity required for crooked logs, subjected to one-time crosscutting, and crook-free medium-quality logs was conducted. When the price of sawn lumber obtained from the crooked logs was equal to that of medium-quality logs, the net revenue obtained from crooked logs became nearly equal to that of medium-quality logs. The results demonstrated that the crooked logs could be used effectively by one-time crosscutting.

Effect of crosscutting crooked sugi (Cryptomeria japonica) logs on sawing yield and quality of sawn lumber Reviewed

Ikami Y., Matsumura Y., Murata K., Tsuchikawa S.

Forest Products Journal Vol. 60 ( 3 ) page： 244 - 248 2010.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Forest Products Journal

DOI： 10.13073/0015-7473-60.3.244

Feasibility of Near-Infrared Spectroscopy for On-Line Grading of Sawn Lumber Reviewed

Takaaki Fujimoto, Yohei Kurata, Kazushige Matsumoto, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 64 ( 1 ) page： 92 - 99 2010.1

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

Near-infrared (NIR) spectroscopy, coupled with multivariate analysis, has been used to evaluate the wood properties of sawn lumber of Japanese larch (Larix kaempferi), whose diffuse reflection spectra were acquired under static and moving conditions. Prediction models of the dynamic modulus of elasticity (E(fr)), the modulus of elasticity in bending tests (E(b)), the bending strength (F(b)), the wood density (DEN), and the moisture content (MC) were developed using partial least squares (PLS) analysis. For all wood properties, models obtained from data collected under the moving condition as an analogue of on-line measurement were superior to those from the static condition data. The regression coefficients for the PLS models predicting the mechanical properties in both static and moving conditions showed clear peaks at the absorption bands due to the three major polymers of wood, i.e., cellulose, hemicellulose, and lignin. NIR spectroscopy has high potential for the on-line grading of sawn lumber.

Feasibility of near-infrared spectroscopy for on-line grading of sawn lumber.

Fujimoto T, Kurata Y, Matsumoto K, Tsuchikawa S

Applied spectroscopy Vol. 64 ( 1 ) page： 92 - 9 2010.1

Feasibility of Near-Infrared Spectroscopy for On-Line Grading of Sawn Lumber

Fujimoto Takaaki, Kurata Yohei, Matsumoto Kazushige, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 64 ( 1 ) page： 92 - 99 2010.1

Feasibility of near infrared spectroscopy for on-line grading of sawn lumber Reviewed

Fujimoto, T.; Kurata, Y.; Matsumoto, K.; Tsuchikawa, S.

Applied Spectroscopy Vol. 64 2010

Effect of Crosscutting Sugi (Cryptomeria japonica D. Don) Logs on Sawing Yield and Quality of Sawn Lumber", Forest Products Journal Reviewed

Ikami, Y.; Matsumura, Y.; Murata, K., Tsuchikawa S.

Forest Products Journal Vol. 60 ( 3 ) page： 244-248 2010

Identification of dead and sound knots by near infrared spectroscopy Invited Reviewed

Fujimoto, T.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 18 2010

Difference of the crystal structure of cellulose in wood after hydrothermal and ageing degradation: A NIR spectroscopy and XRD study Reviewed

Inagaki, T.; Siesler, H.; Mitsui, K.; Tsuchikawa, S.

Biomacromolecules Vol. 11 page： 2300-2306 2010

Feasibility of near infrared spectroscopy for on-line multi-traits assessment of sawn lumber Reviewed

Fujimoto, T.; Kurata, Y.; Matsumoto, K.; Tsuchikawa, S.

Journal of Wood Science Vol. 56 2010

Near Infrared Spectroscopic Assessment of Contamination Level of Sewage Reviewed

Inagaki, T.; Shinoda Y.; Miyazawa, M.; Takamura H.; Tsuchikawa S.

Water Science and Technology Vol. 61 ( 8 ) page： 1957-1963 2010

Difference of the crystal structure of cellulose in wood after hydrothermal and ageing degradation: A NIR spectroscopy and XRD study

Inagaki, T, Siesler, H, Mitsui, K, Tsuchikawa, S

Biomacromolecules Vol. 11 page： 2300-2306 2010

Feasibility of near infrared spectroscopy for on-line multi-traits assessment of sawn lumber

Fujimoto, T, Kurata, Y, Matsumoto, K, Tsuchikawa, S

Journal of Wood Science Vol. 56 2010

Near-infrared spectroscopic assessment of contamination level of sewage Reviewed

Inagaki Tetsuya, Shinoda Yukari, Miyazawa Mitsuhiro, Takamura Hitoshi, Tsuchikawa Satoru

WATER SCIENCE AND TECHNOLOGY Vol. 61 ( 8 ) page： 1957 - 1963 2010

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Water Science and Technology

We examined the use of near infrared (NIR) spectroscopy as a rapid technique for the evaluation of sewage quality. Influent water samples, primary sedimentation tank water samples, and final effluent water samples were collected from sewage treatment facilities in Nagoya, Japan and their NIR spectra obtained. Partial least squares (PLS) models for total phosphate (TP), total nitrogen (TN), biochemical oxygen demand (BOD), total organic carbon (TOC), and turbidity of sewage water were constructed from the NIR data. The models provided good correlation between measurements obtained conventionally and those predicted from spectroscopy. Spectral variation induced by background interference in samples affected accuracy. Loading plots and score plots derived from PLS regression analysis resolved the background interference and allowed highly accurate predictions. Spectral variation induced by contamination in the sewage was a main predictor of sewage quality. These results show that NIR spectroscopy shows potential for in-line, non-destructive measurement of sewage quality. © IWA Publishing 2010.

DOI： 10.2166/wst.2010.070

Near Infrared Spectroscopic Assessment of Contamination Level of Sewage

Inagaki, T, Shinoda Y, Miyazawa, M, Takamura H, Tsuchikawa S

Water Science and Technology Vol. 61 ( 8 ) page： 1957-1963 2010

Identification of dead and sound knots by near infrared spectroscopy Reviewed

Fujimoto Takaaki, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 18 ( 6 ) page： 473 - 479 2010

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

This paper examines the identification of dead and sound knots on the wood surface using near infrared (NIR) spectroscopy. Fifty dead and sound knots samples were prepared and NIR diffuse-reflectance spectra were collected from these samples. The spectra of normal wood were also obtained from the neighbourhood of each knot. The wavenumber range from 6600 cm-1 to 5400 cm-1 (1515 nm to 1852 nm) was employed for the multivariate analysis after taking into consideration characteristics of the spectra. The soft independent modelling of class analogies (SIMCA) classification technique was conducted for classification of dead knots, sound knots and normal wood classes. Specific spectral features were found in dead and sound knots at the following absorption bands: 6130 cm-1, 5980 cm-1, 5800 cm-1 and 5700 cm-1, which were related to bark tissue and compression wood. The SIMCA model could identify the differences between dead and sound knots as well as the presence of knots. The loadings and discrimination powers were consistent with the spectral features, showing peaks due to bark tissue and compression wood. The bands provide useful information to determine the effective range of electromagnetic waves for image analysis. © IM Publications LLP 2010.

DOI： 10.1255/jnirs.887

Near-infrared spectroscopic analysis of aging degradation in antique washi paper using a deuterium exchange method Reviewed

Identification of dead and sound knots by near infrared spectroscopy

Fujimoto, T, Tsuchikawa, S

Journal of Near Infrared Spectroscopy Vol. 18 2010

Feasibility of near infrared spectroscopy for on-line grading of sawn lumber Reviewed

藤本高明, 土川覚

Applied Spectroscopy 64 page： 92 - 99 2010

Yonenobu Hitoshi, Tsuchikawa Satoru, Sato Karina

VIBRATIONAL SPECTROSCOPY Vol. 51 ( 1 ) page： 100 - 104 2009.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Vibrational Spectroscopy

The diffusion process of deuterated water (D2O) in washi (Japanese traditional paper) was investigated by means of a deuterium exchange method and Fourier-transform near-infrared (FT-NIR) transmission spectroscopy. The samples were the modern (AD 2003) hand-made washi and those from an archival collection of cultural artifacts (AD 1791 and 1615). Four absorption bands were identified in the NIR spectral range from 7200 to 6000 cm-1 which are due to OH groups in the amorphous, semi-crystalline and two types of crystalline regions of cellulose. The accessibility of D2O increased with decreasing state of order of cellulose, and the saturation accessibility increased with the age of the samples. It was suggested that during aging hemicellulose, which forms a composite with cellulose in paper, was progressively hydrolyzed, resulting in the expansion of inter-molecular distance between cellulose chains. The oldest sample showed a low diffusion rate compared with the others. SEM observation of the textile structures indicated that the oldest sample had two layers due to beating. It was estimated that the tight surface layer blocked the diffusant in the initial stage of the diffusion process. © 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.vibspec.2008.11.001

Influence of pith location on warp of lumber in sawing medium-quality sugi (Cryptomeria japonica D. Don) logs Reviewed

Ikami, Y; Murata, K; Matsumura, Y; Tsuchikawa, S

EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS Vol. 67 ( 3 ) page： 271 - 276 2009.8

Language：English Publishing type：Research paper (scientific journal) Publisher：European Journal of Wood and Wood Products

The forest and wood industry in Japan require the development of automation technology to produce high-quality lumber from medium-quality sugi (Cryptomeria japonica D. Don) logs. This study investigates the influence of pith location on the warp of lumber. While drying reduced the bow of lumber drastically its crook remained almost unchanged. Therefore, an effective sawing method to reduce crook was sought after. Crook measured immediately after sawing increased as the distance between the center of the lumber and the pith location along the width of lumber increased. A sawing method which takes pith location into account was concluded to be effective in reducing crook. Based on these results, a new sophisticated sawing procedure to produce high-quality lumber is proposed. © 2009 Springer-Verlag.

DOI： 10.1007/s00107-009-0318-0

Near Infrared Spectroscopic Investigation of Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Object. Part-II: Hardwood Reviewed

Inagaki, T.; Mitsui, K.; Tsuchikawa S.

Applied Spectroscopy Vol. 63 ( 7 ) page： 753-758 2009.7

Near-Infrared Spectroscopic Investigation of the Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Wood. Part II: Hardwood Reviewed

Tetsuya Inagaki, Katsuya Mitsui, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 63 ( 7 ) page： 753 - 758 2009.7

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

Near-infrared (NIR) spectroscopy and chemometrics were applied to analyze the degradation mechanism of hardwood following hydrothermal treatment. NIR spectra, chemical composition, oven-dried density, equilibrium moisture content, compressive Young's modulus parallel to grain, and cellulose crystallinity of artificially degraded leech as an analogue of archaeological wood were systematically measured. Partial least squares (PLS) regression analysis was employed to predict compressive Young's modulus using NIR spectra and various properties as independent variables. Results are also compared with previous data obtained from similar treatment of softwood (Hinoki cypress). The increase in cellulose crystallinity of hardwood during the initial stage of hydrothermal treatment (up to 5 hours) was correlated with an improvement in the mechanical properties of wood. Young's modulus for both hardwood and softwood showed a gradual decrease over five hours of hydrothermal treatment, which is proposed to be due to the degradation of polysaccharide.

Near-infrared spectroscopic investigation of the hydrothermal degradation mechanism of wood as an analogue of archaeological wood. Part II: hardwood. Reviewed

Inagaki T, Mitsui K, Tsuchikawa S

Applied spectroscopy Vol. 63 ( 7 ) page： 753 - 8 2009.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Near-infrared (NIR) spectroscopy and chemometrics were applied to analyze the degradation mechanism of hardwood following hydrothermal treatment. NIR spectra, chemical composition, oven-dried density, equilibrium moisture content, compressive Young's modulus parallel to grain, and cellulose crystallinity of artificially degraded beech as an analogue of archaeological wood were systematically measured. Partial least squares (PLS) regression analysis was employed to predict compressive Young's modulus using NIR spectra and various properties as independent variables. Results are also compared with previous data obtained from similar treatment of softwood (Hinoki cypress). The increase in cellulose crystallinity of hardwood during the initial stage of hydrothermal treatment (up to 5 hours) was correlated with an improvement in the mechanical properties of wood. Young's modulus for both hardwood and softwood showed a gradual decrease over five hours of hydrothermal treatment, which is proposed to be due to the degradation of polysaccharide. © 2009 Society for Applied Spectroscopy.

DOI： 10.1366/000370209788701071

Near-Infrared Spectroscopic Investigation of the Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Wood. Part II: Hardwood Reviewed

Inagaki Tetsuya, Mitsui Katsuya, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 63 ( 7 ) page： 753 - 758 2009.7

Application of time-of-flight near infrared spectroscopy to fruits -Analysis of absorption/scattering condition of NIR radiation by cross-correlation function of time-resolved profile- Reviewed

Kurata, Y.; Tsuchikawa S.

Applied Spectroscopy Vol. 63 ( 3 ) page： 306-312 2009.3

Influence of pith location on warp of lumber in sawing medium quality Sugi (Cryptomeria japonica D. Don) logs Reviewed

Ikami, Y.; Matsumura, Y.; Murata, K., Tsuchikawa S.

Holz als Roh- und Werkstoff Vol. 67 ( 3 ) page： 271-276 2009.3

Application of Time-of-Flight Near-Infrared Spectroscopy to Fruits: Analysis of Absorption and Scattering Conditions of Near-Infrared Radiation Using Cross-Correlation of the Time-Resolved Profile Reviewed

Yohei Kurata, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 63 ( 3 ) page： 306 - 312 2009.3

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

The absorption and scattering conditions of near-infrared radiation in a grapefruit, a popular thick-peeled fruit, were investigated by time-of-flight near-infrared spectroscopy (TOF-NIRS). The cross-correlation function was introduced to obtain fine spectroscopic information from the time-resolved profile. Variation of the optical parameters in both the time-resolved profile and the cross-correlation function showed that the NIR radiation was largely absorbed in the peel and considerably scattered in the flesh of the fruit. It also reflected the straightness of the input pulsed laser. The substantial optical path length of the grapefruit estimated from the cross-correlation function was approximately 4 to 5 times as long as the nominal optical path length (NOPL). The cross-correlation function was an effective tool to analyze the absorption/scattering conditions of NIR radiation in a sample where an unstable light source such as a Nd:YAG laser with high output energy was employed.

Application of time-of-flight near-infrared spectroscopy to fruits: analysis of absorption and scattering conditions of near-infrared radiation using cross-correlation of the time-resolved profile. Reviewed

Kurata Y, Tsuchikawa S

Applied spectroscopy Vol. 63 ( 3 ) page： 306 - 12 2009.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

DOI： 10.1366/000370209787599004

Prediction of water content in Ligustrum japonicum leaf using near infrared chemometric imaging Reviewed

Application of Time-of-Flight Near-Infrared Spectroscopy to Fruits: Analysis of Absorption and Scattering Conditions of Near-Infrared Radiation Using Cross-Correlation of the Time-Resolved Profile

Kurata Yohei, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 63 ( 3 ) page： 306 - 312 2009.3

Influence of pith location on warp of lumber in sawing medium quality Sugi (Cryptomeria japonica D. Don) logs Reviewed

Ikami, Y, Matsumura, Y, Murata, K, Tsuchikawa S

Holz als Roh- und Werkstoff Vol. 67 ( 3 ) page： 271-276 2009.3

Near-infrared spectroscopic analysis of aging degradation in antique washi paper using a deuterium exchange method Invited Reviewed

Yonenobu, H.; Sato, K.; Tsuchikawa, S.

Vibrational Spectroscopy Vol. 51 page： 100-104 2009

Prediction of water content in Ligustrum japonicum leaf using NIR chemometric imaging Reviewed

Kobori, H.; Tsuchikawa S.

Journal of Near Infrared Spectroscopy Vol. 17 ( 3 ) page： 151-157 2009

Near-infrared spectroscopic analysis of aging degradation in antique washi paper using a deuterium exchange method

Yonenobu, H, Sato, K, Tsuchikawa, S

Vibrational Spectroscopy Vol. 51 page： 100-104 2009

Kobori Hikaru, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 17 ( 3 ) page： 151 - 157 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

Leaf water content is one of the most important indicators of the plant growth status. However, the traditional measurement of leaf water content requires a destructive process. A new technique using near infrared (NIR) imaging with the aid of chemometrics was developed to predict leaf water content. This method makes it possible to evaluate the leaf water content without destruction. Ligustrum japonicum leaves were taken, and then the water content and spectroscopic images at the wavelength of 1450nm were obtained by a vidicon camera fitted with a band-pass filter. A calibration model able to predict water content with high accuracy was found by partial least square analysis, using cumulative histograms based on the luminance brightness as the explanatory variables. This research confirmed the feasibility of NIR chemometric imaging to monitor the plant growth condition. © IM Publications LLP 2009 All rights reserved.

DOI： 10.1255/jnirs.836

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Prediction of water content in Ligustrum japonicum leaf using NIR chemometric imaging

Kobori, H, Tsuchikawa S

Journal of Near Infrared Spectroscopy Vol. 17 ( 3 ) page： 151-157 2009

Fujimoto T., Matsumoto K., Kurata Y., Tsuchikawa S.

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Near infrared (NIR) spectroscopy, coupled with multivariate analytic statistical techniques, has been used to predict the mechanical properties of solid wood samples taken from small clear and full length lumber specimens of hybrid larch. The specific mechanical characteristics evaluated were the modulus of elasticity (MOE), the modulus of rupture (MOR), compression strength parallel to the grain (CS) in small clear specimens, dynamic modulus of elasticity of air-dried lumbers (Efr), and wood density (DEN). Partial least squares (PLS) regression calibrations were developed for each wood property and found that the calibrations gave relatively strong relationships between laboratory-measured and NIR-predicted values in small clear specimens, with coefficients of determination ranging from 0.61 to 0.89. The calibration models were applied to the prediction data sets (unknown samples), suggesting that NIR spectroscopy has the potential to predict the mechanical properties with adequate accuracy. Comparison of the prediction based on spectra obtained from the radial vs tangential face showed that the prediction models based on spectra obtained from radial face were slightly superior. Although the accuracy of calibration and prediction was lesser than the small clear specimens, reasonable predictive model for wood stiffness could be taken from the full length lumber specimens. Regression coefficients resulting from PLS analysis indicates that variation in wood components such as cellulose, lignin and possibly hemicellulose governs wood mechanical properties.

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T., Matsumoto K., Kurata Y., Tsuchikawa S.

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Rapid and nondestructive evaluations of wood mechanical properties by near infrared spectroscopy Reviewed

Fujimoto T, Matsumoto K, Kurata Y, Tsuchikawa S

10th World Conference on Timber Engineering 2008 Vol. 1 page： 239 - 245 2008.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：10th World Conference on Timber Engineering 2008

Near Infrared Spectroscopic Investigation of Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Object. Part-I: Softwood Reviewed

Inagaki, T.; Mitsui, K.; Tsuchikawa S.

Applied Spectroscopy Vol. 62 ( 11 ) 2008.11

Near-Infrared Spectroscopic Investigation of the Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Objects. Part I: Softwood Reviewed

Tetsuya Inagaki, Katsuya Mitsui, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 62 ( 11 ) page： 1209 - 1215 2008.11

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

The degradation mechanism of softwood due to the variation of strength was analyzed in conjunction with spectroscopy and chemometrics, where the sample was thermally treated with a steam atmosphere. Near-infrared (NIR) spectra, chemical composition, oven-dried density, equilibrium moisture content, compressive Young's modulus parallel to the grain, and cellulose crystallinity of artificially degraded hinoki cypresses as an analogue of archaeological objects were systematically measured. Partial least squares (PI,S) regression analysis was employed to predict compressive Young's modulus using NIR spectra and some kinds of wood properties as independent variables. Good prediction models were obtained for both independent variables. The scores and the loading plots derived from PLS analysis were applied to consistently explain the mechanism of hydrothermal degradation. It was suggested that the variation of compressive Young's modulus with hydrothermal treatment was governed by two main components, that is, depolymerization of polysaccharides and variation of cellulose crystallinity.

Near-infrared spectroscopic investigation of the hydrothermal degradation mechanism of wood as an analogue of archaeological objects. Part I: softwood. Reviewed

Inagaki T, Mitsui K, Tsuchikawa S

Applied spectroscopy Vol. 62 ( 11 ) page： 1209 - 15 2008.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

The degradation mechanism of softwood due to the variation of strength was analyzed in conjunction with spectroscopy and chemometrics, where the sample was thermally treated with a steam atmosphere. Near-infrared (NIR) spectra, chemical composition, oven-dried density, equilibrium moisture content, compressive Young's modulus parallel to the grain, and cellulose crystallinity of artificially degraded hinoki cypresses as an analogue of archaeological objects were systematically measured. Partial least squares (PLS) regression analysis was employed to predict compressive Young's modulus using NIR spectra and some kinds of wood properties as independent variables. Good prediction models were obtained for both independent variables. The scores and the loading plots derived from PLS analysis were applied to consistently explain the mechanism of hydrothermal degradation. It was suggested that the variation of compressive Young's modulus with hydrothermal treatment was governed by two main components, that is, depolymerization of polysaccharides and variation of cellulose crystallinity. © 2008 Society for Applied Spectroscopy.

DOI： 10.1366/000370208786401563

Near-Infrared Spectroscopic Investigation of the Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Objects. Part I: Softwood Reviewed

Inagaki Tetsuya, Mitsui Katsuya, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 62 ( 11 ) page： 1209 - 1215 2008.11

*Discriminant Analyzing System for Wood Wastes Using A Vis-NIR Chemometrical Imaging Technique Reviewed

Kobori, H.; Yonenobu, H.; Tsuchikawa S.

Applied Spectroscopy Vol. 62 ( 8 ) page： 854-859 2008.8

Discriminant analyzing system for wood wastes using a visible-near-infrared chemometric imaging technique Reviewed

Hikaru Kobori, Hitoshi Yonenobu, Junichi Noma, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 62 ( 8 ) page： 854 - 859 2008.8

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

A new optical system was developed and applied to automated separation of wood wastes, using a combined technique of visible-near-infrared (Vis-NIR) imaging analysis and chemometrics. Three kinds of typical wood wastes were used, i.e., non-treated, impregnated, and plastic-film overlaid wood. The classification model based on soft independent modeling of class analogy (SIMCA) was examined using the difference luminance brightness of a sample. Our newly developed system showed a good/promising performance in separation of wood wastes, with an average rate of correct separation of 89%. Hence, it is concluded that the system is efficiently feasible for online monitoring and separation of wood wastes in recycling mills.

Near-infrared spectroscopic monitoring of the water adsorption/desorption process in modern and archaeological wood Reviewed

Tetsuya Inagaki, Hitoshi Yonenobu, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 62 ( 8 ) page： 860 - 865 2008.8

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

We investigated the adsorption/desorption mechanism of water and the variation of water adsorption for modern and archaeological wood using near-infrared spectroscopy. A mixture model of water was used to decompose the near-infrared difference spectra into three components (free water molecules (S-0), those with one OH group engaged in hydrogen bonding (S-1), and those with two OH groups engaged in hydrogen bonding (S-2)) based on a principal component analysis. The variations of each water component with relative humidity could be explained by proposing a model that describes water absorption in three stages. It was concluded that the aging phenomenon in wood is due to the decrease of adsorption sites on hemicellulose and amorphous cellulose.

Discriminant analyzing system for wood wastes using a visible-near-infrared chemometric imaging technique. Reviewed

Kobori H, Yonenobu H, Noma J, Tsuchikawa S

Applied spectroscopy Vol. 62 ( 8 ) page： 854 - 9 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

DOI： 10.1366/000370208785284295

Near-infrared spectroscopic monitoring of the water adsorption/desorption process in modern and archaeological wood. Reviewed

Inagaki T, Yonenobu H, Tsuchikawa S

Applied spectroscopy Vol. 62 ( 8 ) page： 860 - 5 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

We investigated the adsorption/desorption mechanism of water and the variation of water adsorption for modern and archaeological wood using near-infrared spectroscopy. A mixture model of water was used to decompose the near-infrared difference spectra into three components (free water molecules (S0), those with one OH group engaged in hydrogen bonding (S1), and those with two OH groups engaged in hydrogen bonding (S2)) based on a principal component analysis. The variations of each water component with relative humidity could be explained by proposing a model that describes water absorption in three stages. It was concluded that the aging phenomenon in wood is due to the decrease of adsorption sites on hemicellulose and amorphous cellulose. © 2008 Society for Applied Spectroscopy.

DOI： 10.1366/000370208785284312

Estimation of sawn face width of Sugi (Cryptomeria japonica D. Don) logs by cross-sectional shape with approximation profile Reviewed

Near-infrared spectroscopic monitoring of the water adsorption/desorption process in modern and archaeological wood

Inagaki Tetsuya, Yonenobu Hitoshi, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 62 ( 8 ) page： 860 - 865 2008.8

Ikami Y., Matsumura Y., Murata K., Tsuchikawa S.

HOLZ ALS ROH-UND WERKSTOFF Vol. 66 ( 4 ) page： 243 - 247 2008.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Holz als Roh - und Werkstoff

In sawing systems producing high quality lumber from medium diameter sugi (Cryptomeria japonica D. Don) logs, operators must carefully decide the amount of setworks taking into consideration the sawn face width and appearance of knots so that the work efficiency often suffers considerable reduction. A simple mathematical method to estimate the sawn face width on the basis of cross-sectional shape with an approximation profile was proposed. Ninety cross-sectional shapes were measured using a newly developed measuring device and estimated as a circle or an ellipse, where 89% of the cross-sectional shapes fit the ellipses. The error margin in 72-75% of the sawn face width estimates was 2.0 cm or less, which was equal to the conventional value achieved by skilled operators. © 2008 Springer-Verlag.

DOI： 10.1007/s00107-008-0242-8

Near Infrared Spectroscopic Monitoring of the Diffusion Process of Deuterium-Labeled Molecules in Wood Reviewed

Discriminant analyzing system for wood wastes using a visible-near-infrared chemometric imaging technique Reviewed

Kobori Hikaru, Yonenobu Hitoshi, Noma Junichi, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 62 ( 8 ) page： 854 - 859 2008.8

Tsuchikawa S., Siesler H.

Characterization of the Cellulosic Cell Wall page： 123 - 137 2008.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Characterization of the Cellulosic Cell Wall

Near infrared transmission spectroscopy was used to monitor the diffusion process of deuterium-labeled molecules in wood samples. To better understand the state of order in wood cellulose, several diffusion experiments were performed with Sitka spruce and beech in D2O and two OD-deuterated alcohols of different geometry. Four absorption bands in the NIR region (7200-6100 cm-1) were assigned to 2 ×ν (OH) absorptions of OH groups in the amorphous, semi-crystalline, and the two kinds of intramolecularly hydrogen-bonded crystalline regions, respectively. The saturation accessibility varied characteristically with the OH groups in different states of order in the wood substance, the diffusants, and the wood species, respectively. The effect of the anatomical cellular structure on the accessibility is reflected in the variation of the diffusion rate with wood species. We proposed a new interpretation about the fine structure of the microfibrils in the cell wall by comparing a series of results for hardwood and softwood specimens. © 2006 Blackwell Publishing.

DOI： 10.1002/9780470999714.ch10

Monitoring of hydroxyl groups in wood during heat treatment using NIR spectroscopy Reviewed

Mitsui Katsuya, Inagaki Tetsuya, Tsuchikawa Satoru

BIOMACROMOLECULES Vol. 9 ( 1 ) page： 286 - 288 2008.1

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Biomacromolecules

This paper deals with the evaluation of thermally treated wood by near-infrared (NIR) spectroscopy. In the NIR second derivative spectrum, the absorption band at 6913 cm-1 appeared with the procession of heat treatment, which conclusively assigned to the phenolic hydroxyl groups due to the lignin in comparison with the spectrum of acetylated spruce wood. As a result of the changes in the ratio of the areal integral calculated from spectral separation in the region of hydroxyl groups (7200-6100 cm-1) by the Gauss-Newton method, it was clear that the degradation of hydroxyl group in the cellulose started predominantly from the amorphous region and followed to semicrystalline and crystalline region. There was an obvious correlation between the weight decrement of wood and the decrement of hydroxyl groups in the cellulose by heat treatment. © 2008 American Chemical Society.

DOI： 10.1021/bm7008069

Application of near infrared spectroscopy for estimating wood mechanical properties of small clear and full length lumber specimens Reviewed

Monitoring of Hydroxyl Groups in Wood during Heat Treatment Using NIR Spectroscopy Reviewed

Mitsui, K.; Inagaki, T.; Tsuchikawa S.

Biomacromolecules Vol. 9 page： 286-288 2008

Application of near infrared spectroscopy for estimating wood mechanical properties of small clear and full length lumber specimens Reviewed

Fujimoto, T.; Kurata, Y.; Matsumoto, K.; Tsuchikawa, S.

Journal of Near Infrared Spectroscopy Vol. 16 page： 529-537 2008

*NIR spectroscopic monitoring of water adsorption/desorption process in modern and archaeological wood" Reviewed

Inagaki, T.; Yonenobu, H.; Tsuchikawa S.

Applied Spectroscopy Vol. 62 ( 8 ) page： 861-865 2008

Estimation of Sawn Face Width of Sugi (Cryptomeria japonica D. Don) Logs by Cross-Sectional Shape with Approximation Profile Reviewed

Ikami, Y.; Matsumura, Y.; Murata, K., Tsuchikawa S.

Holz als Roh- und Werkstoff Vol. 66 ( 4 ) page： 243-247 2008

*Application of time-of-flight near infrared spectroscopy to fruits -Permeability of pulsed laser into Satsuma mandarin, White grapefruit and Fuji apple- Reviewed

Kurata, Y.; Ikemoto, Y.; Tsuchikawa S.

Journal of Near Infrared Spectroscopy Vol. 16 page： 139-142 2008

*Application of time-of-flight near infrared spectroscopy to fruits -Permeability of pulsed laser into Satsuma mandarin, White grapefruit and Fuji apple-

Kurata, Y, Ikemoto, Y, Tsuchikawa S

Journal of Near Infrared Spectroscopy Vol. 16 page： 139-142 2008

Fujimoto Takaaki, Kurata Yohei, Matsumoto Kazushige, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 16 ( 6 ) page： 529 - 537 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

Near infrared (NIR) spectroscopy, coupled with multivariate analytic statistical techniques, has been used to predict the mechanical properties of solid wood samples taken from small clear and full length lumber specimens of hybrid larch (Larix gmelinii var. japonica x Larix kaempferi). The specific mechanical characteristics evaluated were modulus of elasticity (MOE), modulus of rupture (MOR) in bending tests, maximum crushing strength in compression parallel to grain (CS), dynamic modulus of elasticity of air-dried lumbers (Efr), and wood density (DEN). Partial least squares (PLS) regression calibrations were developed for each wood property. The calibrations had relatively strong relationships between laboratory-measured and NIR-predicted values in small clear specimens, with coefficients of determination ranging from 0.61 to 0.89. The calibration models were applied to the prediction data sets and results suggested that NIR spectroscopy has the potential to predict mechanical properties of small clears with adequate accuracy (standardised prediction error=2.06-2.82). The PLS models based on spectra from the radial face (R2=0.73-0.89) of wood were slightly superior to those from the tangential face (R2=0.61-0.84). This might be due to the differences of the surface condition in terms of the anatomical structures and, thus, radial face better represents the sample. A reasonable predictive model for wood stiffness was also obtained from the full length lumber specimens, but the accuracy of the calibration for prediction was less than the small clear specimens (R2=0.49-0.78). The regression coefficients obtained from the PLS models showed similar trends in all mechanical properties. It was suggested that the absorption bands due to the OH-groups in cellulose were the major contributors to building robust models for predicting the mechanical properties of wood © IM Publications LLP 2008 All rights reserved.

DOI： 10.1255/jnirs.818

Application of near infrared spectroscopy for estimating wood mechanical properties of small clear and full length lumber specimens Reviewed

Takaaki Fujimoto, Yohei Kurata, Kazushige Matsumoto, Satoru Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 16 ( 6 ) page： 529 - 537 2008

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

Near infrared (NIR) spectroscopy, coupled with multivariate analytic statistical techniques, has been used to predict the mechanical properties of solid wood samples taken from small clear and full length lumber specimens of hybrid larch (Larix gmelinii var.japonica x Larix kaempferi). The specific mechanical characteristics evaluated were modulus of elasticity (MOE), modulus of rupture (MOR) in bending tests, maximum crushing strength in compression parallel to grain (CS) dynamic modulus of elasticity of air-dried lumbers (E(fr)), and wood density (DEN). Partial least squares (PLS) regression calibrations were developed for each wood property. The calibrations had relatively strong relationships between laboratory-measured and NIR-predicted values in small clear specimens, with coefficients of determination ranging from 0.61 to 0.89. The calibration models were applied to the prediction data sets and results suggested that NIR spectroscopy has the potential to predict mechanical properties of small clears with adequate accuracy (standardised prediction error=2.06-2.82). The PLS models based on spectra from the radial face (R(2)=0.73-0.891 of wood were slightly superior to those from the tangential face (R(2)=0.61-0.84). This might be due to the differences of the surface condition in terms of the anatomical structures and, thus, radial face better represents the sample. A reasonable predictive model for wood stiffness was also obtained from the full length lumber specimens, but the accuracy of the calibration for prediction was less than the small clear specimens (R(2)=0.49-0.78). The regression coefficients obtained from the PLS models showed similar trends in all mechanical properties. It was suggested that the absorption bands due to the OH-groups in cellulose were the major contributors to building robust models for predicting the mechanical properties of wood

DOI： 10.1255/jnirs.813

Short communication - Application of time-of-flight near infrared spectroscopy to fruits-permeability of pulsed laser beam into Satsuma mandarin, White grapefruit and Fuji apple Reviewed

Estimation of Sawn Face Width of Sugi (Cryptomeria japonica D. Don) Logs by Cross-Sectional Shape with Approximation Profile

Ikami, Y, Matsumura, Y, Murata, K, Tsuchikawa S

Holz als Roh- und Werkstoff Vol. 66 ( 4 ) page： 243-247 2008

Monitoring of Hydroxyl Groups in Wood during Heat Treatment Using NIR Spectroscopy

Mitsui, K, Inagaki, T, Tsuchikawa S

Biomacromolecules Vol. 9 page： 286-288 2008

Kurata Yohei, Ikernoto Yuka, Tsuchikawa Satoru

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 16 ( 2 ) page： 139 - 142 2008

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

The permeability of a pulsed laser beam into Satsuma mandarin, White grapefruit and Fuji apple was compared by time-of-flight near infrared (ToF-NIR) spectroscopy. In this study, a compact measurement system including a dye-doped plastic laser cavity with a wavelength of 800 nm and an avalanche photodiode were employed. The NIR radiation attenuance (i.e. optical density) in apple was higher than in the citrus fruit. The peak maxima of transmitted radiation of intact Satsuma mandarin increased 130 times more than that of intact grapefruit. Differences in diameter related directly to attenuance. The peak maxima of transmitted radiation of peeled grapefruit increased 250 times more than that of intact grapefruit; however, these increases were not found for Satsuma mandarin or apple. NIR radiation attenuance of the grapefruit peel was greater than for the peel of the other fruits. The incident pulsed laser beam was uniformly scattered in the citrus sample, whereas the scattering condition of the pulsed laser beam in apple might not be uniform because of the presence of core tissue. Thus, while the pulsed laser beam could be transmitted through citrus fruit and apple, the effect of fruit size and peel on the NIR radiation attenuance characteristically varied. © IM Publications LLP 2008 All rights reserved.

DOI： 10.1255/jnirs.764

Estimation of wood stiffness and strength properties of hybrid larch by near-infrared spectroscopy. Reviewed

Estimation of Wood Stiffness and Strength Properties of Hybrid Larch by Near-infrared Spectroscopy", Applied Spectroscopy Reviewed

Fujimoto, T.; Yamamoto, H.; Tsuchikawa, S.

Applied Spectroscopy Vol. 61 ( 8 ) page： 882-888 2007.8

Estimation of wood stiffness and strength properties of hybrid larch by near-infrared spectroscopy

Fujimoto Takaaki, Yamamoto Hiroyuki, Tsuchikawa Satoru

APPLIED SPECTROSCOPY Vol. 61 ( 8 ) page： 882 - 888 2007.8

Fujimoto T, Yamamoto H, Tsuchikawa S

Applied spectroscopy Vol. 61 ( 8 ) page： 882 - 8 2007.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

This work was undertaken to investigate the feasibility of near-infrared (NIR) spectroscopy for estimating wood mechanical properties, i.e., modulus of elasticity (MOE) and modulus of rupture (MOR) in bending tests. Two sample sets having large and limited density variation were prepared to examine the effects of wood density on estimation of MOE and MOR by the NIR technique. Partial least squares (PLS) analysis was employed and it was found that the relationships between laboratorymeasured and NIR-predicted values were good in the case of sample sets having large density variation. MOE could be estimated even when density variation in the sample set was limited. It was concluded that absorption bands due to the OH group in the semi-crystalline or crystalline regions of cellulose strongly influenced the calibrations for bending stiffness of hybrid larch. This was also suggested from the result that both a-cellulose content and cellulose crystallinity showed moderate positive correlation to wood stiffness. © 2007 Society for Applied Spectroscopy.

DOI： 10.1366/000370207781540150

Estimation of wood stiffness and strength properties of hybrid larch by near-infrared spectroscopy Reviewed

Takaaki Fujimoto, Hiroyuki Yamamoto, Satoru Tsuchikawa

APPLIED SPECTROSCOPY Vol. 61 ( 8 ) page： 882 - 888 2007.8

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

This work was undertaken to investigate the feasibility of near-infrared (NIR) spectroscopy for estimating wood mechanical properties, i.e., modulus of elasticity (MOE) and modulus of rupture (MOR) in bending tests. Two sample sets having large and limited density variation were prepared to examine the effects of wood density on estimation of MOE and MOR by the NIR technique. Partial least squares (PLS) analysis was employed and it was found that the relationships between laboratory-measured and NIR-predicted values were good in the case of sample sets having large density variation. MOE could be estimated even when density variation in the sample set was limited. It was concluded that absorption bands due to the OH group in the semi-crystalline or crystalline regions of cellulose strongly influenced the calibrations for bending stiffness of hybrid larch. This was also suggested from the result that both alpha-cellulose content and cellulose crystallinity showed moderate positive correlation to wood stiffness.

第2回近赤外分光部会シンポジウム Reviewed

土川覚

分光研究 = Journal of the spectroscopical research of Japan Vol. 56 ( 2 ) page： 86 2007.4

第2回近赤外分光部会シンポジウム

土川覚

分光研究 = Journal of the spectroscopical research of Japan Vol. 56 ( 2 ) 2007.4

第2回近赤外分光部会シンポジウム Reviewed

土川覚

分光研究 = Journal of the spectroscopical research of Japan Vol. 56 ( 2 ) page： 86 2007.4

第2回近赤外分光部会シンポジウム Reviewed

土川覚

分光研究 = Journal of the spectroscopical research of Japan Vol. 56 ( 2 ) page： 86 2007.4

*A Review of Recent Near Infrared Research for Wood and Paper Invited Reviewed

Tsuchikawa, S.

Applied Spectroscopy Review Vol. 42 ( 1 ) page： 43-71 2007

*A Review of Recent Near Infrared Research for Wood and Paper

Tsuchikawa, S

Applied Spectroscopy Review Vol. 42 ( 1 ) page： 43-71 2007

A review of recent near infrared research for wood and paper Reviewed

Tsuchikawa Satoru

APPLIED SPECTROSCOPY REVIEWS Vol. 42 ( 1 ) page： 43 - 71 2007

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy Reviews

This review article introduces recent technical and scientific reports in terms of near infrared (NIR) spectroscopy in the wood and paper science and industry, where interest has increased during the last couple decades. Many researchers reported the NIR technique was useful to detect multi information in both chemical and physical properties of wood materials, although it was widely used in a state where characteristic cellular structure was retained. In the case of application of NIR spectroscopy to pulp and paper, many publications have pointed out its high probability as online measurement techniques during paper-making process control. Arguments referred to the importance of NIR spectroscopy as fundamental and applied research of wood and paper. Copyright © Taylor & Francis Group, LLC.

DOI： 10.1080/05704920601036707

Instrumentation: Instruments

Mcclure W.

Near-Infrared Spectroscopy in Food Science and Technology page： 73 - 108 2006.2

Instrumentation: Time-of-Flight Spectroscopy

Tsuchikawa S.

Near-Infrared Spectroscopy in Food Science and Technology page： 109 - 120 2006.2

Sampling Techniques Reviewed

Tsuchikawa S

Near-Infrared Spectroscopy in Food Science and Technology page： 133 - 143 2006.2

Near infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood

Tsuchikawa Satoru, Siesler H. W.

CHARACTERIZATION OF THE CELLULOSIC CELL WALL page： 123 - + 2006

Low atmospheric temperature dependence on photo degradation of wood Reviewed

K Mitsui, S Tsuchikawa

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY Vol. 81 ( 2 ) page： 84 - 88 2005.11

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

This paper deals with the photodegradation of wood in low atmospheric temperature region (-40 to 50 degrees C), and discusses the changes in color and IR spectra. The color and IR spectra of wood hardly changed with photo-irradiation at -40 degrees C but did at -20 degrees C. Therefore, it is thought that the photo-energy causes the scission of chemical bonds or the production of radicals; however, heat energy is needed to yellow of wood (i.e., to produce quinone). In case of softwoods, the absorption of the carbonyl band consisted of two sub-bands, and the carbonyl band at around 1710 cm(-1) increased at lower temperature than that at around 1760 cm(-1) by light-irradiation. Such IR measurement due to lignin degradation means that the photodegradation of softwoods is faster than that of hardwoods. The color change by exposure to light in the low temperature was also caused by the degradation of lignin. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotobiol.2005.05.011

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp Reviewed

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Terdwongworakul Anupun, Punsuwan Vittaya, Thanapase Warunee, TSUCHIKAWA Satoru

Journal of wood science Vol. 51 ( 2 ) page： 167 - 171 2005.4

TERDWONGWORAKUL Anupun, PUNSUWAN Vittaya, THANAPASE Warunee, TSUCHIKAWA Satoru

Journal of Wood Science Vol. 51 ( 2 ) page： 167 - 171 2005.4

Near-infrared spectroscopic study of the physical and mechanical properties of wood with meso- and micro-scale anatomical observation

Tsuchikawa S, Hirashima Y, Sasaki Y, Ando K

APPLIED SPECTROSCOPY Vol. 59 ( 1 ) page： 86 - 93 2005.1

Near-infrared spectroscopic study of the physical and mechanical properties of wood with meso- and micro-scale anatomical observation. Reviewed

Tsuchikawa S, Hirashima Y, Sasaki Y, Ando K

Applied spectroscopy Vol. 59 ( 1 ) page： 86 - 93 2005.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Estimation of the density along with the tensile strength of wood within both the elastic and plastic deformation ranges, represented as modulus of elasticity (MOE) and ultimate tensile stress (UTS), respectively, were performed using near-infrared (NIR) spectroscopy. A partial least squares (PLS) analysis was applied to the measurements of density, MOE, and UTS, and resulted in a high accuracy of prediction, independent of wood species. The correlation coefficient between the NIR spectra and criterion variables, and the regression vector resulting from the PLS analysis, suggested that the characteristic absorption bands were strongly related to the predictability of each property. In the case of softwood, absorption bands due to intra-molecular hydrogen-bonded OH groups in the crystalline regions of cellulose, which are oriented preferentially in a direction parallel to the cellulose chain, might strongly affect the tensile strength of softwood. Hardwoods have much more complex and variable structures than softwoods; therefore, it was supposed that the key factor governing the tensile strength in hardwood would be the interaction between the three principal constituents (i.e., cellulose, hemicellulose, and lignin) of wood.

DOI： 10.1366/0003702052940413

Near-infrared spectroscopic study of the physical and mechanical properties of wood with meso- and micro-scale anatomical observation Reviewed

S Tsuchikawa, Y Hirashima, Y Sasaki, K Ando

APPLIED SPECTROSCOPY Vol. 59 ( 1 ) page： 86 - 93 2005.1

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

Application of near infrared spectroscopy to assessments of colour change in plantation-grown Eucalyptus grandis wood subjected to heat and steaming treatments Reviewed

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantation by near infrared spectroscopy aiming high quality pulp wood selection Reviewed

Terdwongworakul, A.; Punsuwan, V.; Thanapase, W.; Tsuchikawa, S.

Journal of Wood Science Vol. 51 page： 167-171 2005

*Near-infrared spectroscopic observation of the ageing process in archaeological wood using a deuterium exchange method Reviewed

Tsuchikawa, S.; Yonenobu, H.; Siesler, H. W.

The Analyst Vol. 130 page： 379-384 2005

Application of near infrared spectroscopy to assessments of colour change in plantation-grown Eucalyptus grandis wood subjected to heat and steaming treatments Reviewed

Wu Y.Q.; Tsuchikawa S.; Hayashi K.

Journal of Near Infrared Spectroscopy Vol. 13 page： 371-376 2005

Low atmospheric temperature dependence on photodegradation of wood Reviewed

Mitsui, K.; Tsuchikawa S.

Journal of Photochemistry and Photobiology B: Biology Vol. 81 page： 84-88 2005

Near-infrared spectroscopic study of the physical and mechanical properties of wood with meso- and micro-scale anatomical observation Reviewed

Tsuchikawa, S.; Hirashima, Y.; Sasaki, Y.; Ando, K.

Applied Spectroscopy Vol. 59 ( 1 ) page： 78-85 2005

Near-infrared spectroscopic observation of the ageing process in archaeological wood using a deuterium exchange method. Reviewed

土川覚

The Analyst. 130 page： 379 - 384 2005

*Near-infrared spectroscopic observation of the ageing process in archaeological wood using a deuterium exchange method

Tsuchikawa, S, Yonenobu, H, Siesler, H. W

The Analyst Vol. 130 page： 379-384 2005

Wu Y.Q., Tsuchikawa S., Hayashi K.

Journal of Near Infrared Spectroscopy Vol. 13 ( 6 ) page： 371 - 376 2005

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

The relationships between colour parameters and chemical components of Eucalyptus grandis wood under a steaming and a heating process were examined by near infrared (NIR) spectroscopy to assess the best drying conditions. The results indicated that: 1) under steaming conditions, the second derivatives of absorption bands due to OH in the crystalline region of cellulose and CH in hemicellulose presented statistically significant positive correlation values for L* or b* and a decrease in lignin might be the reason leading to the colour changes; 2) under heat-treated conditions, the colour darkening process in wood was often accompanied by a severe collapse phenomena, especially at the 100°C condition. It was found spectroscopically that the concentrations of cellulose and hemicellulose were increased relatively by the collapse occurring and that lignin decreased with the elevated drying temperature. The crystalline regions in cellulose and hemicellulose were related to "blueness" (partial darkness) of E. grandis caused by the drying process. © NIR Publications 2005.

DOI： 10.1255/jnirs.568

Application of near infrared spectroscopy to assessments of colour change in plantation-grown Eucalyptus grandis wood subjected to heat and steaming treatments Reviewed

YQ Wu, S Tsuchikawa, K Hayashi

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 13 ( 6 ) page： 371 - 376 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

The relationships between colour parameters and chemical components of Eucalyptus grandis wood under a steaming and a heating process were examined by near infrared (NIR) spectroscopy to assess the best drying conditions. The results indicated that: 1) under steaming conditions, the second derivatives of absorption bands due to OH in the crystalline region of cellulose and CH in hemicellulose presented statistically significant positive correlation values for V or b* and a decrease in lignin might be the reason leading to the colour changes; 2) under heat-treated conditions, the colour darkening process in wood was often accompanied by a severe collapse phenomena, especially at the 100 degrees C condition. It was found spectroscopically that the concentrations of cellulose and hemicellulose were increased relatively by the collapse occurring and that lignin decreased with the elevated drying temperature. The crystalline regions in cellulose and hemicellulose were related to "blueness" (partial darkness) of E. grandis caused by the drying process.

Near-infrared spectroscopic observation of the ageing process in archaeological wood using a deuterium exchange method Reviewed

Application of near infrared spectroscopy to assessments of colour change in plantation-grown Eucalyptus grandis wood subjected to heat and steaming treatments

Wu YQ, Tsuchikawa S, Hayashi K

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 13 ( 6 ) page： 371 - 376 2005

Tsuchikawa S, Yonenobu H, Siesler HW

ANALYST Vol. 130 ( 3 ) page： 379 - 384 2005

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Analyst

The ageing degradation of the fine wood structure of dry-exposed archaeological wood was investigated by Fourier transform near-infrared spectroscopy with the aid of a deuterium exchange method. The archaeological wood sample was taken from an old wooden temple in Japan (late 7th century), which has been designated as a UNESCO world heritage site. Comparing the analytical results with those of a modern wood sample of the same species, the ageing process of archaeological wood was clarified as a change in the state of order on a macromolecular structural level. It can be concluded from NIR spectra that the amorphous region, and partially semi-crystalline region, in cellulose, hemicellulose, and lignin decreased by the ageing degradation, whereas the crystalline region in cellulose was not affected by the ageing. The accessibility of the diffusant to effect H/D-exchange was monitored by an OH-related absorption band obtained from FT-NIR transmission spectroscopy and characteristically varied with the ageing process of the wood samples, the absorption bands characteristic of a specific state of order and the diffusion agent. Finally, we proposed a morphological model to describe the variation of the fine structure of the microfibrils in the cell wall with ageing degradation. The state of microfibrils changed loosely by ageing, so that elementary fibrils were arranged loosely under 5 Å, whereas several elementary fibrils in the modern wood were arranged in very close proximity under 3 Å to each other. © The Royal Society of Chemistry 2005.

DOI： 10.1039/b412759e

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantation by near infrared spectroscopy aiming high quality pulp wood selection

Terdwongworakul, A, Punsuwan, V, Thanapase, W, Tsuchikawa, S

Journal of Wood Science Vol. 51 page： 167-171 2005

Terdwongworakul A, Punsuwan V, Thanapase W, Tsuchikawa S

JOURNAL OF WOOD SCIENCE Vol. 51 ( 2 ) page： 167 - 171 2005

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of α-cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees. © The Japan Wood Research Society 2005.

DOI： 10.1007/s10086-004-0633-3

Near-Infrared Spectroscopic Study of the Physical and Mechanical Properties of Wood with Meso-and Micro-Scate Anatomical Observation. Reviewed

土川覚

Applied Spectroscopy 59・1 page： 86 - 93 2005

Near-infrared spectroscopic observation of the ageing process in archaeological wood using a deuterium exchange method Reviewed

土川覚

The Analyst 130 page： 379 - 384 2005

Near-Infrared Spectroscopic Study of the Physical and Mechanical Propertics of Wood with Meso- and Micro-Scale Anatomical Observation Reviewed

土川覚

Applied Spectroscopy 59・1 page： 86 - 93 2005

Near-Infrared Spectroscopic Study of the Physical and Mechanical Properties of Wood with Meso-and Micro-Scale Anatomical Observation Reviewed

土川覚

Applied Spectroscopy 59・1 page： 86 - 93 2005

Spectroscopic monitoring of wood characteristics variation by light-irradiation Reviewed

Tsuchikawa, S; Inoue, K; Mitsui, K

FOREST PRODUCTS JOURNAL Vol. 54 ( 11 ) page： 71 - 76 2004.11

Spectroscopic monitoring of wood characteristics variation by light-irradiation Reviewed

Tsuchikawa S., Inoue K., Mitsui K.

Forest Products Journal Vol. 54 ( 11 ) page： 71 - 76 2004.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Forest Products Journal

This study deals with the feasibility of near-infrared (NIR) spectroscopy to qualitatively monitor the variation in wood characteristics caused by ultraviolet light-irradiation. It was found from the second derivative NIR spectra that OH groups in the amorphous regions in cellulose, hemicellulose, and lignin could be easily decomposed into low molecular matter by light-irradiation. The degradation rates for the amorphous regions in cellulose and hemicellulose were faster than that for lignin. Such degradation of main chemical compounds in wood by light-irradiation was closely associated with yellowing of the samples. The ratio of the second derivative of absorbance (Rλ) at λ nm after light-irradiation to before irradiation, was investigated. In the case of OH groups in the amorphous region, we could not find an obvious difference in the trend of Rλ, between wood species. However, it was suggested from Rλ that the decomposition state of lignin by light-irradiation varied characteristically with wood species. Furthermore, we found a strong correlation between Rλ due to lignin and chroma coordinates (i.e.; δb*), independent of wood species. In the case of hemicellulose, there were considerable differences in Rλ vs. δb* between softwoods and hardwoods.

Wood photography using light irradiation and heat treatment Reviewed

K Mitsui, A Murata, S Tsuchikawa, M Kohara

COLOR RESEARCH AND APPLICATION Vol. 29 ( 4 ) page： 312 - 316 2004.8

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS INC

To apply the coloring method using light irradiation and thermal treatment to print photographs on wood, the effect of the transmittance of negative films was investigated. DeltaE* decreased with light irradiation when specimens covered with films with transmittances exceeding 20% were irradiated for 100 h. It was thought that this phenomenon was due to the decrease in Deltab*. The color of light-irradiated wood changed remarkably with thermal treatment; however, the change in the color of exposed specimens covered with films with transmittances exceeding roughly, 20% became constant. Clear photographs could be printed on wood using negative films with transmittances less than approximately 20%. Furthermore, the difference between the maximum and minimum values of DeltaE* after thermal treatment was about 22. Humans can distinguish four to seven colors that can be created by this method. (C) 2004 Wiley Periodicals, Inc.

DOI： 10.1002/col.20027

Application of time-of-flight near infrared spectroscopy for detecting sugar and acid contents in apples Reviewed

Tsuchikawa S, Hamada T

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY Vol. 52 ( 9 ) page： 2434 - 2439 2004.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Agricultural and Food Chemistry

A newly constructed optical measurement system was introduced to nondestructively measure the composition of the inside of an apple by time-of-flight near-infrared spectroscopy (TOF-NIRS). As sugar content increased, optical parameters concerned with time-resolved profile of transmitted pulsed light (the attenuance of peak maxima, At, the time delay of peak maxima, Δt, and the variation of full width at half-maximum, Δw) decreased gradually. When the acid content increased, At and Δw increased; however, a significant tendency could not be found for Δt. At, Δt, and Δw were employed as the explanatory variables for multiple linear regression, principle component regression, and partial least-squares analysis. It was possible to predict both sugar and acid contents in an apple with high precision by TOF-NIRS. Especially, the superiority of TOF-NIRS lied in more precise determination of acid content.

DOI： 10.1021/jf030705v

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

New dating technique for wood-based cultural properties using near infrared spectroscopy(Proceedings of the 16^<th> Symposium on Researches Using the Tandetron AMS System at Nagoya University in 2003)

Yonenobu Hitoshi, Tsuchikawa Satoru, Oda Hirotaka, Siesler Heinz W.

Summaries of Researches using AMS at Nagoya University ( 15 ) page： 74 - 82 2004.3

Publisher：Nagoya University

Non-destructive measurement of properties were investigated for wood-based cultural properties using near infrared spectroscopy (NIRS). Antique samples of washi paper scrolls and a pillar member of old wooden building were used for the analysis of temporal degradation. The results obtained show good agreement with the conventional, destructive analysis. In consequence, it is concluded that NIRS shows good potential as a non-destructive dignostic tool for wood-based cultural properties. New non-destructive dating technique was developed using dendrochronologically dated wood samples. NIR absorbance peaks for main wood components show highly linear correlation with tree-ring dates. Partial least regression was performed to calibrate NIR absorbance to age. The NIR dating method shows good performance in accuracy which is almost close to those in tree-ring dating and is higher than those in AMS radiocarbon dating.

DOI： 10.18999/sumrua.15.74

Spectroscopic Monitoring of Wood Characteristics Variation by Light-Irradiation Reviewed

"Tsuchikawa, S.; Inoue, K.; Mitsui K."

Forest Products Journal Vol. 54 page： 71-76 2004.1

Spectroscopic Monitoring of Wood Characteristics Variation by Light-Irradiation Reviewed

Tsuchikawa, S, Inoue, K, Mitsui K

Forest Products Journal Vol. 54 page： 71-76 2004.1

Wood Photography Using Light-Irradiation and Heat Treatment Reviewed

Mitsui, K.; Murata, A.; Tsuchikawa, S.; Kohara M.

Color Research and Application Vol. 29 ( 4 ) page： 312-315 2004

Application of Time-of-Flight Near Infrared Spectroscopy for Detecting Sugar and Acid Contents in Apples Reviewed

Tsuchikawa, S.; Hamada, T.

Journal of Agricultural and Food Chemistry Vol. 52 ( 9 ) page： 2434-2439 2004

Tsuchikawa, S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

Application of Time-of-Flight Near Infrared Spectroscopy for Detecting Sugar and Acid Contents in Apples

Tsuchikawa, S, Hamada, T

Journal of Agricultural and Food Chemistry Vol. 52 ( 9 ) page： 2434-2439 2004

Damage cumulation on wood by composition of several loading factors

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 2 ) page： 129 - 131 2004

Damage cumulation on wood by composition of several loading factors Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 2 ) page： 129 - 131 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa, S.

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

Damage cumulation on wood by composition of several loading factors Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 2 ) page： 129 - 131 2004

近赤外分光法による新しい考古計測学の確立 Reviewed

米延仁志, 土川覚

第20回記念非破壊分析シンポジウム講演要旨集 20 page： 91 - 97 2004

近赤外分光法による新しい考古計測学の確立 Reviewed

米延仁志, 土川覚

第20回記念非破壊分析シンポジウム講演要旨集 20 page： 91 - 97 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa, S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa, S.

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

"Nondestructive measurement and analysis of physical properties for wood by near infrared spectroscopy" Reviewed

Tsuchikawa S

MOKUZAI GAKKAISHI Vol. 50 ( 3 ) page： A10 - A12 2004

近赤外分光法による木質系廃棄物の判別分析 Invited

"土川覚,山登香織"

木材保存 Vol. 29 page： 259-262 2003.11

Near-infrared spectroscopic comparison of antique and modern wood

Yonenobu H, Tsuchikawa S

APPLIED SPECTROSCOPY Vol. 57 ( 11 ) page： 1451 - 1453 2003.11

Near-infrared spectroscopic comparison of antique and modern wood. Reviewed

Yonenobu H, Tsuchikawa S

Applied spectroscopy Vol. 57 ( 11 ) page： 1451 - 3 2003.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

The temporal degradation of old wooden building material was estimated by using near-infrared (NIR) spectrometry. The difference second-derivative NIR spectra suggest that hemicellulose and holocellulose decreased while lignin increased relatively. It was revealed that nondestructive NIR spectroscopy is a useful technique in examining properties of antique wood.

DOI： 10.1366/000370203322554635

近赤外分光法による木質系廃棄物の判別分析 Invited Reviewed

土川覚, 山登香織

木材保存 Vol. 29 page： 259-262 2003.11

Application of near-infrared spectroscopy to wood discrimination Reviewed

Tsuchikawa S., Inoue K., Noma J., Hayashi K.

Journal of Wood Science Vol. 49 ( 1 ) page： 29 - 35 2003.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

This study deals with a new nondestructive discriminant analysis by which wood can be classified on the basis of a combination of near-infrared (NIR) spectroscopy and Mahalanobis' generalized distance. Its accuracy and reasonability were examined for wood samples with various moisture contents ranging from oven-dried to a fully saturated free water state. In a discriminant analysis employing second derivative spectra, each wood group was well distinguished. Mahalanobis' generalized distances between softwoods are relatively independent of analytical pattern, whereas the distances between hardwoods are large for easy classification. There may be two reasons for selecting a wavelength: (1) when the chemical component of wood substance relates to the discriminant analysis; and (2) when the difference in moisture content with wood species relates to them. When we correctly construct the database of NIR spectra, confirming the purpose of the analysis, suitable wood discrimination should be possible.

DOI： 10.1007/s100860300005

Discriminant analysis of wood-based materials using near-infrared spectroscopy Reviewed

Tsuchikawa S., Yamato K., Inoue K.

Journal of Wood Science Vol. 49 ( 3 ) page： 275 - 280 2003.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Wood Science

This study deals with the suitable discriminant techniques of wood-based materials by means of near-infrared spectroscopy (NIRS) and several chemometric analyses. The concept of Mahalanobis' generalized distance, K nearest neighbors (KNN), and soft independent modeling of class analogy (SIMCA) were evaluated to determine the best analytical procedure. The difference in the accuracy of classification with the spectrophotometer, the wavelength range as the explanatory variables, and the light-exposure condition of the sample were examined in detail. It was difficult to apply Mahalanobis' generalized distances to the classification of wood-based materials where NIR spectra varied widely within the sample category. The performance of KNN in the NIR region (800-2500nm), for which the device used in the laboratory was employed, exhibited a high rate of correct answers of validation (>98%) independent of the light-exposure conditions of the sample. When employing the device used in the field, both KNN and SIMCA revealed correct answers of validation (>88%) at wavelengths of 550-1010nm. These results suggest the applicability of NIRS to a reasonable classification of used wood at the factory and at job sites.

DOI： 10.1007/s10086-002-0471-0

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: hardwood. Reviewed

Discriminant analysis of wood-based materials using near-infrared spectroscopy

Tsuchikawa Satoru, Yamato Kaori, Inoue Kinuyo

Journal of wood science Vol. 49 ( 3 ) page： 275 - 280 2003.6

Discriminant analysis of wood-based materials using near-infrared spectroscopy Reviewed

TSUCHIKAWA Satoru, YAMATO Kaori, INOUE Kinuyo

Journal of Wood Science Vol. 49 ( 3 ) page： 275 - 280 2003.6

近赤外分光法の木材非破壊検査への応用 Invited

土川覚

木工機械 Vol. 197 page： 2-5 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part I: Softwood

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 667 - 674 2003.6

Tsuchikawa S, Siesler HW

Applied spectroscopy Vol. 57 ( 6 ) page： 675 - 81 2003.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Fourier transform near-infrared (FT-NIR) transmission spectroscopy was applied to monitor the diffusion process of deuterium-labeled molecules in hardwood (Beech). The results are compared with previous data obtained on softwood (Sitka spruce) in order to consistently understand the state of order in cellulose of wood. The saturation accessibility and diffusion rate varied characteristically with the OH groups in different states of order in the wood substance, the diffusants, and the wood species, respectively. The variation of saturation accessibility should be associated with the fundamental difference of the fine structure such as the microfibrils in the wood substance. The effect of the anatomical cellular structure on the accessibility was reflected in the variation of the diffusion rate with the wood species. The size effect of the diffusants also played an important role for the diffusion process in wood. Since the volumetric percentage of wood fibers and wood rays is relatively similar, the dichroic effects due to the anisotropy of the cellulose chains were apparently diminished. Finally, we proposed a new interpretation of the fine structure of the microfibrils in the cell wall by comparing a series of results from hardwood and softwood. Each elementary fibril in the hardwood has a more homogeneous arrangement in the microfibrils compared to that in the softwood.

DOI： 10.1366/000370203322005373

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part I: softwood. Reviewed

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Tsuchikawa S, Siesler HW

Applied spectroscopy Vol. 57 ( 6 ) page： 667 - 74 2003.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

The diffusion process of several molecules (D2O, n-butanol (OD) and t-butanol (OD)) In softwood (Sitka spruce) was investigated by means of a deuterium exchange method and Fourier transform near-infrared (FT-NIR) polarization spectroscopy. The location of OH groups in different states of order of cellulose in wood was clarified by analyzing the FT-NIR transmission spectra ranging from 7200 to 6000 cm-1. Four absorption bands were assigned to 2 × ν(OH) absorptions of the amorphous regions, OH groups in semicrystalline regions, and two types of intramolecular hydrogen-bonded OH groups in the crystalline regions, respectively. The saturation level of accessibility was very different for these absorption bands (i.e., 70-80, 60, and 40-50% for the amorphous, semi-crystalline, and crystalline regions, respectively). However, the saturation accessibilities for each absorption band varied little with molecular structure and geometry of the diffusants. The diffusion rate of D2O was much faster than that of n-butanol (OD) and t-butanol (OD) for all states of orders. The size effect of the butanols led to slight differences in the diffusive transport in the crystalline regions.

DOI： 10.1366/000370203322005364

Application of time-of-flight near-infrared spectroscopy to detect sugar and acid content in Satsuma mandarin Reviewed

近赤外分光法の木材非破壊検査への応用 Invited

土川覚

木工機械 Vol. 197 page： 2-5 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood, Part. 1 : softwood Reviewed

TSUCHIKAWA S

Appl Spectrosc Vol. 57 ( 6 ) page： 667 - 674 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S., Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Near-infrared spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa S, Siesler HW

APPLIED SPECTROSCOPY Vol. 57 ( 6 ) page： 675 - 681 2003.6

Application of time-of-flight near-infrared spectroscopy to detect sugar and acid content in Satsuma mandarin

Tsuchikawa S, Sakai E, Inoue K, Miyamoto K

JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE Vol. 128 ( 3 ) page： 391 - 396 2003.5

Tsuchikawa S., Sakai E., Inoue K., Miyamoto K.

Journal of the American Society for Horticultural Science Vol. 128 ( 3 ) page： 391 - 396 2003.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of the American Society for Horticultural Science

Time-of-flight near infrared spectroscopy (TOF-NIRS) was applied to the detection of sugar and acid content in Satuma mandarin (Citrus unshiu Marc). The combined effects on the time resolved profiles of soluble solids, free acids, laser beam wavelength, and detection position of transmitted light were investigated in detail. Attenuance of peak maxima (At) and time delay of peak maxima (Δt) increased as sugar content increased. However, these optical parameters decreased with increases in acid content. In the case of a model sample of a polyurethane block immersed in specified solutions, At and Δt decreased by adding sucrose or citric acid. These results suggested that time resolved profile was governed not only by the concentration of soluble solid or free acid but also by other inherent factors of a fruit; for example, an optical characteristic of tissue or difference in refractive index between the tissue substance and the liquid. Results indicated the optimum optical parameters for detection of sugar and acid content were At and Δt, respectively.

DOI： 10.21273/jashs.128.3.0391

Application of Near Infrared Spectroscopy (NIR) to light-irradiated wood Reviewed

Mitsui, K; Tsuchikawa, S

HOLZ ALS ROH-UND WERKSTOFF Vol. 61 ( 2 ) page： 159 - 160 2003.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Holz als Roh - und Werkstoff

The absorbility of water in wood varies with the light-irradiation time. Thus, near infrared spectroscopy proved to be a useful method allowing the detection of changes in chemical structure of wood after light-irradiation. In addition, it may also be suitable for the realization of a new coloring method of wood.

DOI： 10.1007/S00107-002-0361-6

Application of near-infrared spectroscopy to wood discrimination

Tsuchikawa Satoru, Inoue Kinuyo, Noma Junichi, HAYASHI Kazuo

Journal of wood science Vol. 49 ( 1 ) page： 29 - 35 2003.2

Application of near-infrared spectroscopy to wood discrimination Reviewed

TSUCHIKAWA Satoru, INOUE Kinuyo, NOMA Junichi, HAYASHI Kazuo

Journal of Wood Science Vol. 49 ( 1 ) page： 29 - 35 2003.2

Application of Near Infrared Spectroscopy to Light-Irradiated Wood Reviewed

"Mitsui, K.; Tsuchikawa, S."

Holz als Roh- und Werkstoff Vol. 61 page： 159-160 2003.1

Discriminant Analysis of Wood Based Materials using Near Infrared Spectroscopy. Reviewed

"Tsuchikawa, S.; Yamato, K.; Inoue, K."

Journal of Wood Science Vol. 49 page： 275-280 2003.1

Near-infrared Spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part I: Softwood Reviewed

"Tsuchikawa, S.; Siesler, H. W."

Applied Spectroscopy Vol. 57 page： 667-674 2003.1

Near-infrared Spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

"Tsuchikawa, S.; Siesler, H. W."

Applied Spectroscopy Vol. 57 page： 675-681 2003.1

Non-destructive NIR Spectroscopic Measurement of Antique Washi Calligraphic Scrolls Reviewed

"Yonenobu, H.; Tsuchikawa, S."

Journal of Near Infrared Spectroscopy Vol. 11 page： 407-411 2003.1

Near-Infrared Spectroscopic Comparison of Antique and Modern Wood Reviewed

"Yonenobu, H.; Tsuchikawa, S."

Applied Spectroscopy Vol. 57 ( 11 ) page： 1451-1453 2003.1

Application of time-of-flight near infrared spectroscopy for detecting sugar content and acidity in apples Invited

"Tsuchikawa, S.; Hamada, T."

NIR news Vol. 14 page： 6-8 2003.1

Discriminant Analysis of Wood Based Materials with Weathering Damage by Near Infrared Spectroscopy Reviewed

"Tsuchikawa, S.; Yamato, K."

Journal of Near Infrared Spectroscopy Vol. 11 page： 391-399 2003.1

Application of time-of-flight near-infrared spectroscopy for detection of sugar content and acid degrees in Satsuma Mandarin Reviewed

"Tsuchikawa, S.; Sakai, E.; Inoue, K.; Miyamoto, K."

Journal of American Society of Horticultural Science Vol. 128 page： 391-396 2003.1

Near-Infrared Spectroscopic Comparison of Antique and Modern Wood Reviewed

Yonenobu, H, Tsuchikawa, S

Applied Spectroscopy Vol. 57 ( 11 ) page： 1451-1453 2003.1

Application of time-of-flight near-infrared spectroscopy for detection of sugar content and acid degrees in Satsuma Mandarin Reviewed

Tsuchikawa, S, Sakai, E, Inoue, K, Miyamoto, K

Journal of American Society of Horticultural Science Vol. 128 page： 391-396 2003.1

Application of Near Infrared Spectroscopy to Light-Irradiated Wood Reviewed

Mitsui, K, Tsuchikawa, S

Holz als Roh- und Werkstoff Vol. 61 page： 159-160 2003.1

Application of time-of-flight near infrared spectroscopy for detecting sugar content and acidity in apples Invited Reviewed

Tsuchikawa, S, Hamada, T

NIR news Vol. 14 page： 6-8 2003.1

Near-infrared Spectroscopic monitoring of the diffusion process of deuterium-labeled molecules in wood. Part II: Hardwood Reviewed

Tsuchikawa, S., Siesler, H.

Applied Spectroscopy Vol. 57 ( 6 ) page： 675-681 - 681 2003.1

Spectroscopic Monitoring of Biomass Modification by Light-Irradiation with Heat Treatment Reviewed

"Tsuchikawa, S.; Murata, A.; Kohara, M.; Mitsui K."

Journal of Near Infrared Spectroscopy Vol. 11 page： 401-405 2003

Evaluation of Elastic Modulus of Wood Surface Using Small Specimen

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 61 - 63 2003

Copying Photographic Images on Wood Surface by Light-Irradiation and Heat Treatment

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 57 - 60 2003

Discriminant analysis of wood-based materials using near-infrared spectroscopy

Tsuchikawa S, Yamato K, Inoue K

JOURNAL OF WOOD SCIENCE Vol. 49 ( 3 ) page： 275 - 280 2003

Discriminant analysis of wood-based materials with weathering damage by near infrared spectroscopy

Tsuchikawa S, Yamato K

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 391 - 399 2003

Non-destructive near infrared spectroscopic measurement of antique washi calligraphic scrolls

Yonenobu H, Tsuchikawa S, Oda H

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 407 - 411 2003

近赤外分光法による木質系廃棄物の判別分析

土川覚, 山登香織

木材保存 Vol. 29 ( 6 ) page： 259 - 262 2003

Discriminant analysis of wood-based materials with weathering damage by near infrared spectroscopy Reviewed

S Tsuchikawa, K Yamato

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 391 - 399 2003

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

This research was aimed at finding a suitable discriminate technique for wood-based materials which had suffered from weathering damage, as an analogue of waste wood condition, by means of near infrared (NIR) spectroscopy and several kinds of chemometrics. The feasibility of Mahalanobis generalised distance, K nearest neighbours (KNN) or soft independent modelling of class analogy (SIMCA) as the classification method of wooden materials was examined in detail. The differences in the accuracy of classification with the spectrophotometer (for example, laboratory use and field use), pre-treatment of NIR spectra or the wavelength range as the explanatory variables were also taken into account. Five categories of wood-based materials (solid wood, laminated wood, particle or fibreboard, impregnated wood and overlaid wood) were exposed to outdoor sunlight for up to six months. It was difficult to apply Mahalanobis generalised distance to the classification of five material types where the NIR spectra varied greatly with the sample categories. Both of KNN and SIMCA presented the highest correct classification of over 93%, independent of the spectrophotometer. These results support the applicability of NIR spectroscopy to the classification of waste wood at the actual factory and job site.

Discriminant analysis of wood-based materials using near-infrared spectroscopy Reviewed

S Tsuchikawa, K Yamato, K Inoue

JOURNAL OF WOOD SCIENCE Vol. 49 ( 3 ) page： 275 - 280 2003

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER-VERLAG TOKYO

This study deals with the suitable discriminant techniques of wood-based materials by means of near-infrared spectroscopy (NIRS) and several chemometric analyses. The concept of Mahalanobis' generalized distance. K nearest neighbors (KNN), and soft independent modeling of class analogy (SIMCA) were evaluated to determine the best analytical procedure. The difference in the accuracy of classification with the spectrophotometer. the wavelength range as the explanatory variables, and the light-exposure condition of the sample were examined in detail. It was difficult to apply Mahalanobis' generalized distances to the classification of wood-based materials where NIR spectra varied widely within the sample category. The performance of KNN in the NIR region (800-2500nm). for which the device used in the laboratory was employed, exhibited a high rate of correct answers of validation (>98%) independent of the light-exposure conditions of the sample. When employing the device used in the field. both KNN and SIMCA revealed correct answers of validation (>88%) at wavelengths of 550-1010nm. These results suggest the applicability of NIRS to a reasonable classification of used wood at the factory and at job sites.

Application of near-infrared spectroscopy to wood discrimination Reviewed

S Tsuchikawa, K Inoue, J Noma, K Hayashi

JOURNAL OF WOOD SCIENCE Vol. 49 ( 1 ) page： 29 - 35 2003

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER-VERLAG TOKYO

This study deals with a new nondestructive discriminant analysis by which wood can be classified on the basis of a combination of near-infrared (NIR) spectroscopy and Mahaianobis' generalized distance. Its accuracy and reasonability were examined for wood samples with various moisture contents ranging from oven-dried to a fully saturated free water state. In a discriminant analysis employing second derivative spectra, each wood group was well distinguished. Mahalanobis' generalized distances between softwoods are relatively independent of analytical pattern, whereas the distances between hardwoods are large for easy classification. There may be two reasons for selecting a wavelength: (1) when the chemical component of wood substance relates to the discriminant analysis; and (2) when the difference in moisture content with wood species relates to them. When we correctly construct the database of NIR spectra, confirming the purpose of the analysis, suitable wood discrimination should be possible.

Copying Photographic Images on Wood Surface by Light-Irradiation and Heat Treatment Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 57 - 60 2003

Evaluation of Elastic Modulus of Wood Surface Using Small Specimen Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 61 - 63 2003

Application of near-infrared spectroscopy to wood discrimination Reviewed

Tsuchikawa S, Inoue K, Noma J, Hayashi K

JOURNAL OF WOOD SCIENCE Vol. 49 ( 1 ) page： 29 - 35 2003

Spectroscopic monitoring of biomass modification by light-irradiation and heat treatment Reviewed

Tsuchikawa S., Murata A., Kohara M., Mitsui K.

Journal of Near Infrared Spectroscopy Vol. 11 ( 5 ) page： 401 - 405 2003

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

This study discusses the use of near infrared spectroscopy for monitoring of the process by which biomass is modified by light-irradiation and heat treatment. As a change in the colour of wood is closely related to the change in its physicochemical structure, we investigated the relationship between the tristimulus values and the diffusely-reflected near infrared spectra of wood samples during a constrained modification process. Such basic research is required to develop a new method of colouring wood without paint. The change in colour with heat treatment was much greater in light-irradiated wood than in non-irradiated wood. The change in the colour of wood by light-irradiation and heat treatment is related to the degradation of lignin and hemicellulose, which was evident from the variation of absorption bands at 1672 nm for CH in aromatic skeletal and 1724 nm for CH in furanose or pyranose. NIR spectroscopy will become a useful method for the detection of a change in chemical structure of wood caused by light-irradiated and heat treatment.

DOI： 10.1255/jnirs.391

Non-destructive near infrared spectroscopic measurement of antique washi calligraphic scrolls Reviewed

Spectroscopic monitoring of biomass modification by light-irradiation and heat treatment Reviewed

Tsuchikawa S, Murata A, Kohara M, Mitsui K

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 401 - 405 2003

Yonenobu H., Tsuchikawa S., Oda H.

Journal of Near Infrared Spectroscopy Vol. 11 ( 5 ) page： 407 - 411 2003

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

Degradation of antique washi paper was examined by non-destructive near infrared spectroscopy. Difference second derivative spectra of the modern minus antique samples were analysed for the absorption peaks due to the main chemical components of washi paper, i.e. cellulose and hemicellulose. The absorption peaks were decreased for amorphous and semi-crystalline regions of cellulose and for hemicellulose, showing the results consistent with conventional, destructive sugar analysis. It is concluded that near infrared spectroscopy is a useful technique for the non-destructive monitoring of the degradation of the chemical properties of washi paper.

DOI： 10.1255/jnirs.392

Discriminant analysis of wood-based materials with weathering damage by near infrared spectroscopy Reviewed

Tsuchikawa S., Yamato K.

Journal of Near Infrared Spectroscopy Vol. 11 ( 5 ) page： 391 - 399 2003

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

DOI： 10.1255/jnirs.390

Non-destructive near infrared spectroscopic measurement of antique washi calligraphic scrolls Reviewed

H Yonenobu, S Tsuchikawa, H Oda

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 407 - 411 2003

Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

Spectroscopic monitoring of biomass modification by light-irradiation and heat treatment Reviewed

S Tsuchikawa, A Murata, M Kohara, K Mitsui

JOURNAL OF NEAR INFRARED SPECTROSCOPY Vol. 11 ( 5 ) page： 401 - 405 2003

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：N I R PUBLICATIONS

This study discusses the use of near infrared spectroscopy for monitoring of the process by which biomass is modified by light-irradiation and heat treatment. As a change in the colour of wood is closely related to the change in its physicochemical structure, we investigated the relationship between the tristimulus values and the diffusely-reflected near infrared spectra of wood samples during a constrained modification process. Such basic research is required to develop a new method of colouring wood without paint. The change in colour with heat treatment was much greater in light-irradiated wood than in non-irradiated wood. The change in the colour of wood by light-irradiation and heat treatment is related to the degradation of lignin and hemicellulose, which was evident from the variation of absorption bands at 1672 nm for CH in aromatic skeletal and 1724 urn for CH in furanose or pyranose. NIR spectroscopy will become a useful method for the detection of a change in chemical structure of wood caused by light-irradiated and heat treatment.

Evaluation of Elastic Modulus of Wood Surface Using Small Specimen Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 61 - 63 2003

Copying Photographic Images on Wood Surface by Light-Irradiation and Heat Treatment Reviewed

KOHARA Mitsuhiro, MITSUI Katsuya, MURATA Akihiro, TSUCHIKAWA Satoru

Science report of the Faculty of Education, Gifu University. Natural science Vol. 28 ( 1 ) page： 57 - 60 2003

Application of time-of-flight near infrared spectroscopy to wood with anisotropic cellular structure. Reviewed

"Tsuchikawa, S.; Tsutsumi, S."

Aplied Spectroscopy Vol. 56 page： 869-876 2002.7

Application of time-of-flight near-infrared Spectroscopy to wood with anisotropic cellular structure

Tsuchikawa S, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 56 ( 7 ) page： 869 - 876 2002.7

Application of time-of-flight near-infrared Spectroscopy to wood with anisotropic cellular structure Reviewed

S Tsuchikawa, S Tsutsumi

APPLIED SPECTROSCOPY Vol. 56 ( 7 ) page： 869 - 876 2002.7

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SOC APPLIED SPECTROSCOPY

The newly constructed optical measurement system, which was mainly composed of a parametric tunable laser and a near-infrared photoelectric multiplier, was introduced to clarify the optical characteristics of wood with anisotropic cellular structure on the basis of the time-of-flight near-infrared spectroscopy (TOF-NIRS). The combined effects of the cellular structure of the wood sample, the wavelength of the laser beam, and the detection position of transmitted light on the time-resolved profiles were investigated in detail. The substantial optical pathlength calculated from the time-resolved profile was outstandingly larger than the sample thickness. The substance of the wood was directly related to the time delay of light propagation. In applying TOF-NIRS to the cellular structural materials, it is very important to give attention to the difference in the light scattering within the cell wall and that caused by the multiple specular-like reflections between cell walls. The newly proposed empirical equation, considering the effects of optical parameters, could well express the wavelength and sample thickness dependency of the time delay of the peak maxima. The time-resolved profile was intensively governed by the combination of light-absorbing and -scattering conditions and the degree of anisotropy. These basic data will be essential for this system to put an in-process measurement system in the wood industry to practical use.

Application of time-of-flight near-infrared spectroscopy to wood with anisotropic cellular structure Reviewed

Tsuchikawa S., Tsutsumi S.

Applied Spectroscopy Vol. 56 ( 7 ) page： 869 - 876 2002.7

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

DOI： 10.1366/000370202760171545

Application of time-of-flight near-infrared spectroscopy for detecting water core in apples. Reviewed

"Tsuchikawa, S.; Kumada, S.; Inoue, K.; Cho, R."

Journal of American Society of Horticultural Science Vol. 127 page： 303-308 2002.3

Application of time-of-flight near-infrared spectroscopy for detecting water core in apples

Tsuchikawa S, Kumada S, Inoue K, Cho RK

JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE Vol. 127 ( 2 ) page： 303 - 308 2002.3

Application of time-of-flight near-infrared spectroscopy for detecting water core in apples Reviewed

S Tsuchikawa, S Kumada, K Inoue, RK Cho

JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE Vol. 127 ( 2 ) page： 303 - 308 2002.3

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC HORTICULTURAL SCIENCE

Time-of-flight near-infrared spectroscopy (TOF-NIRS) was used to investigate optical characteristics of water-cored tissue in 'Fuji' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh. Mansf.)]. The combined effects on the time resolved profiles of water core, laser beam wavelength, and detection position of transmitted light were investigated in detail. Attenuance of peak maxima (A(t)), time delay of peak maxima (Deltat), and variation of full width at half maximum (Deltaw) decreased gradually as water core increased. Water-cored tissue transmitted much more energy because of the filling of intercellular spaces with liquid, so that the light path time through a sample decreased. These parameters were also strongly dependent on detection position and wavelength of the laser beam. The substantial optical path length calculated from Deltat at lambda = 800 run was 10 to 17 times, while that for lambda = 900 nm varied from six to 11 times the distance of the diameter of the fruit. Results indicated the optimum optical parameter for detection of water core was Deltat.

Application of time-of-flight near-infrared spectroscopy for detecting water core in apples Reviewed

Application of near infrared spectroscopy to wood discrimination. Reviewed

"Tsuchikawa, S.; Inoue, K.; Noma, J.; Hayashi, K."

Journal of Wood Science Vol. 49 page： 29-35 2002.1

Non-traditional Application of Time-of-Flight Near Infrared Spectroscopy to Biological Material Having Cellular Structure Reviewed

TSUCHIKAWA Satoru

Analytical Sciences/Supplements Vol. 17icas ( 0 ) page： i463 - i466 2002

Tsuchikawa S., Kumada S., Inoue K., Cho R.K.

Journal of the American Society for Horticultural Science Vol. 127 ( 2 ) page： 303 - 308 2002

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of the American Society for Horticultural Science

Time-of-flight near-infrared spectroscopy (TOF-NIRS) was used to investigate optical characteristics of water-cored tissue in 'Fuji' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh. Mansf.)]. The combined effects on the time resolved profiles of water core, laser beam wavelength, and detection position of transmitted light were investigated in detail. Attenuance of peak maxima (At), time delay of peak maxima (Δt), and variation of full width at half maximum (Δw) decreased gradually as water core increased. Water-cored tissue transmitted much more energy because of the filling of intercellular spaces with liquid, so that the light path time through a sample decreased. These parameters were also strongly dependent on detection position and wavelength of the laser beam. The substantial optical path length calculated from Δt λ = 800 nm was 10 to 17 times, while that for λ = 900 nm varied from six to 11 times the distance of the diameter of the fruit. Results indicated the optimum optical parameter for detection of water core was Δt.

DOI： 10.21273/jashs.127.2.303

Directional characteristics of near infrared light reflected from wood Reviewed

Tsuchikawa S., Torii M., Tsutsumi S.

Holzforschung Vol. 55 ( 5 ) page： 534 - 540 2001.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Holzforschung

A near infrared auto-goniophotometer was designed to acquire detailed information on optical characteristics of a biological material which had a cellular structure, such as wood. The reflected light, which originated from the irradiation of polarized near infrared light, was separated into an unpolarized and a polarized component by using two polarizing filters. The standardized reflected intensities of each component at various incident angles θ and observation angles η, ρ,up(θ, η) and ρp(θ, η), were measured. Sitka spruce samples with various thicknesses were used. The measurements showed that the directional characteristics of the unpolarized component were affected significantly by the irradiation conditions and the sample thickness. Particularly, these varied with the wavelength of incident light λ. This shows that the directional characteristics models we proposed previously are reasonable. On the other hand, matrices of the directional characteristics for polarized components typically show an elliptical shape which is strongly affected by incident angle and only slighly by λ. Based on these results, the effects of sample thickness on the spectral directional characteristics were determined.

DOI： 10.1515/HF.2001.086

Non-traditional Application of Time-of-Flight Near Infrared Spectroscopy to Biological Material Having Cellular Structure Invited Reviewed

Tsuchikawa S.

Analytical Sciences Vol. 17 page： 463-466 2001.10

Non-traditional Application of Time-of-Flight Near Infrared Spectroscopy to Biological Material Having Cellular Structure Invited Reviewed

Tsuchikawa S

Analytical Sciences Vol. 17 page： 463-466 2001.10

Directional Characteristics of Near Infrared Light Reflected from Wood Reviewed

"Tsuchikawa, S., Torii, M. and Tsutsumi, S."

Holzforschung Vol. 55 page： 534-540 2001.8

Analysis of macroscopic interaction between wood substance and water molecule by near infrared spectroscopy Invited Reviewed

RECENT RECEARCH DEVELOPMENTS IN MATERIALS SCENCE Vol. 3 page： 269-283 2001

Directional characteristics of near infrared light reflected from wood

Tsuchikawa S, Torii M, Tsutsumi S

HOLZFORSCHUNG Vol. 55 ( 5 ) page： 534 - 540 2001

Directional characteristics of near infrared light reflected from wood Reviewed

S Tsuchikawa, M Torii, S Tsutsumi

HOLZFORSCHUNG Vol. 55 ( 5 ) page： 534 - 540 2001

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER & CO

A near infrared auto-goniophotometer was designed to acquire detailed information on optical characteristics of a biological material which had a cellular structure, such as wood. The reflected light, which originated from the irradiation of polarized near infrared light, was separated into an unpolarized and a polarized component by using two polarizing filters. The standardized reflected intensities of each component at various incident angles theta and observation angles eta, rho (up)(theta, eta) and rho (p)(theta, eta), were measured. Sitka spruce samples with various thicknesses were used. The measurements showed that the directional characteristics of the unpolarized component were affected significantly by the irradiation conditions and the sample thickness. Particularly, these varied with the wavelength of incident light lambda. This shows that the directional characteristics models we proposed previously are reasonable. On the other hand, matrices of the directional characteristics for polarized components typically show an elliptical shape which is strongly affected by incident angle and only slightly by lambda. Based on these results, the effects of sample thickness on the spectral directional characteristics were determined.

Analysis of macroscopic interaction between wood substance and water molecule by near infrared spectroscopy Invited Reviewed

RECENT RECEARCH DEVELOPMENTS IN MATERIALS SCENCE Vol. 3 page： 269-283 2001

第34回名古屋国際木工機械展の概要

土川覚

木材工業 = Wood industry Vol. 55 ( 3 ) page： 118 - 121 2000.3

第34回名古屋国際木工機械展の概要 Reviewed

土川覚

木材工業 = Wood industry Vol. 55 ( 3 ) page： 118 - 121 2000.3

第34回名古屋国際木工機械展の概要 Reviewed

土川覚

木材工業 = Wood industry Vol. 55 ( 3 ) page： 118 - 121 2000.3

Non-traditional application of NIRS to detect physical and chemical conditions of biological materials Invited Reviewed

"Tsuchikawa, S.; Tsutsumi, S."

Recent Research Developments in Applied Spectroscopy Vol. 3 page： 113-134 2000.1

Nondestructive Measurement of Wood Properties by Using Near-Infrared Laser Radiation Reviewed

"Tsuchikawa, S., Takahashi, T. and Tsutsumi, S."

Forest Products Journal Vol. 50 page： 81-86 2000.1

Nondestructive measurement of wood properties by using near-infrared laser radiation Reviewed

Tsuchikawa S, Takahashi T, Tsutsumi S

FOREST PRODUCTS JOURNAL Vol. 50 ( 1 ) page： 81 - 86 2000.1

Non-traditional application of NIRS to detect physical and chemical conditions of biological materials Invited Reviewed

Tsuchikawa, S, Tsutsumi, S

Recent Research Developments in Applied Spectroscopy Vol. 3 page： 113-134 - 134 2000.1

Nondestructive measurement of wood properties by using near-infrared laser radiation Reviewed

S Tsuchikawa, T Takahashi, S Tsutsumi

FOREST PRODUCTS JOURNAL Vol. 50 ( 1 ) page： 81 - 86 2000.1

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：FOREST PRODUCTS SOC

This study deals with the construction of a practical nondestructive measurement system with a semiconductor near-infrared laser, by which some information at the deeper position of a sample could be measured more correctly than that by the traditional spectrophotometer. A series of experiments was carried out by giving attention to some geometric conditions of illumination (incident angle, etc.), physical conditions (sample thickness, direction of fiber, etc.), and moisture content (MC). It was revealed that the transmitted output power, Pt, varied characteristically with the combination of geometric conditions of illumination and physical conditions of a sample. The measurable sample thickness substantially exceeded the spectrophotometer with low output power. Pt increased with increasing MC. In particular, we could readily measure Pt for thicker samples involving free water, whereas it was hardly detected in the air-dried condition. The elimination of the air spaces in wood by free water was associated with the reduction of light scattering, so that much more energy would be transmitted. The near-infrared laser system will undoubtedly exhibit good performance for the nondestructive measurement of large wood articles.

Nondestructive measurement of wood properties by using near-infrared laser radiation Reviewed

Tsuchikawa S., Takahashi T., Tsutsumi S.

Forest Products Journal Vol. 50 ( 1 ) page： 81 - 86 2000.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Forest Products Journal

This study deals with the construction of a practical nondestructive measurement system with a semiconductor near-infrared laser, by which some information at the deeper position of a sample could be measured more correctly than that by the traditional spectrophotometer. A series of experiments was carried out by giving attention to some geometric conditions of illumination (incident angle, etc.), physical conditions (sample thickness, direction of fiber, etc.), and moisture content (MC). It was revealed that the transmitted output power, Pt, varied characteristically with the combination of geometric conditions of illumination and physical conditions of a sample. The measurable sample thickness substantially exceeded the spectrophotometer with low output power. Pt increased with increasing MC. In particular, we., could readily measure Pt for thicker samples involving free water, whereas it was hardly detected in the air-dried condition. The elimination of the air spaces in wood by free water was associated with the reduction of light scattering, so that much more energy would be transmitted. The near-infrared laser system will undoubtedly exhibit good performance for the nondestructive measurement of large wood articles.

Analytical characterization of reflected and transmitted light from cellular structural material for the parallel beam of NIR incident light Reviewed

Analytical characterization of reflected and transmitted light from cellular structural material for the parallel beam of NIR incident light

Tsuchikawa S, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 53 ( 9 ) page： 1033 - 1039 1999.9

Tsuchikawa S., Tsutsumi S.

Applied Spectroscopy Vol. 53 ( 9 ) page： 1033 - 1039 1999.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

The results of several studies show clearly that the behavior of light transmitted in wood samples is considerably different from that of an ideal scattering medium. These observations suggest that the Kubelka-Munk theory (the K-M theory) cannot be applied directly to biological material with a cellular structure. We have developed new concepts to understand the optical characteristics of a sample having cellular structure for the illumination condition of the available spectrometers. Through a series of examinations, it became clear that the behavior of diffusely reflected light in wood was accurately described by the K-M theory. However, the behavior of its transmitted light was considerably different from that of an ideal scattering medium under the conditions of Lambert's cosine law. A two-component model of the diffusion process with respect to a parallel beam component of incident light was considered. Furthermore, the nth power cosine model of radiant intensity was introduced to be fitted for the actual state of the radiation in wood. On the basis of these optical models, the mean optical pathlength through the sample was calculated, which allowed the concept of the equivalent sample thickness to be derived. Over and above these considerations, generalized input/output equations for radiation were constructed by introducing the equivalent sample thickness into K-M equations. The absorbance calculated by such concepts agreed well with the experimental values.

DOI： 10.1366/0003702991948026

Directional Characteristics Model and Light-Path Model for Biological Material Having Cellular Structure Reviewed

Directional characteristics model and light-path model for biological material having cellular structure

Tsuchikawa S, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 53 ( 2 ) page： 233 - 240 1999.2

Tsuchikawa S., Tsutsumi S.

Applied Spectroscopy Vol. 53 ( 2 ) page： 233 - 240 1999.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Nondestructive measurements, based on NIRS (near-infrared spectroscopy), on biological material having cellular structure, such as wood, require a nontraditional approach. In this respect, a truly nondestructive measurement system that can accurately monitor the physical condition and chemical components of materials is very desirable. Supported by a series of experiments, we constructed optical characteristic concepts that account for the cellular structure of a sample. The system was successfully modeled by following theoretically the sequential propagation of light in a sample (specifically, scattering, reflection, absorption, and transmission), which varies according to the angle of the fibers with respect to the direction of incident light, θ, and with its wavelength. A set of optical models, which consists of a directional characteristics model and a light-path model, has been developed to describe the various steps in the sequence. On the basis of these models, the leakage ratios of diffusely reflected light from the aggregate width of semi-infinite tracheids, S(θ), for various conditions of irradiation were calculated. These values were in good agreement with the actual values obtained from the measured values of absorbance through the judicious use of a semi-theoretical equation.

DOI： 10.1366/0003702991946370

Optical models of biological materials to develop non-traditional NIR analysis Invited Reviewed

"Tsuchikawa, S.; Tsutsumi, S."

Recent Research Developments in Applied Spectroscopy Vol. 2 page： 1-18 1999.1

Analytical Characterization of Reflected and Transmitted Light from Cellular Structural Material for the Parallel Beam of NIR Incident Light Reviewed

"Tsuchikawa, S. and Tsutsumi, S."

Applied Spectroscopy Vol. 53 page： 1033-1039 1999.1

Directional Characteristics Model and Light-Path Model for Biological Material Having Cellular Structure Reviewed

"Tsuchikawa, S. and Tsutsumi, S."

Applied Spectroscopy Vol. 53 page： 233-240 1999.1

Directional Characteristics Model and Light-Path Model for Biological Material Having Cellular Structure Reviewed

Tsuchikawa, S, Tsutsumi, S

Applied Spectroscopy Vol. 53 page： 233-240 1999.1

Analytical Characterization of Reflected and Transmitted Light from Cellular Structural Material for the Parallel Beam of NIR Incident Light Reviewed

Tsuchikawa, S, Tsutsumi, S

Applied Spectroscopy Vol. 53 page： 1033-1039 1999.1

Optical models of biological materials to develop non-traditional NIR analysis Invited Reviewed

Tsuchikawa, S, Tsutsumi, S

Recent Research Developments in Applied Spectroscopy Vol. 2 page： 1-18 1999.1

Non-traditional applications of NIRS based on the optical characteristic models for a biological material having cellular structure. Reviewed

"Tsuchikawa, S.,"

Journal of Near Infrared Spectroscopy Vol. 6 page： 41-46 1998.1

Directional characteristics of near-infrared light in the process of radiation a transmission from wood. Reviewed

"Tsuchikawa, S., Torii, M., and Tsutsumi, S.,"

Journal of Near Infrared Spectroscopy Vol. 6 page： 47-53 1998.1

Adsorptive a capillary coensed water in biological material. Reviewed

"Tsuchikawa, S, and Tsutsumi, S.,"

Journal of Materials Science Letters Vol. 17 page： 661-663 1998.1

Adsorptive and capillary condensed water in biological material

Tsuchikawa S, Tsutsumi S

JOURNAL OF MATERIALS SCIENCE LETTERS Vol. 17 ( 8 ) page： 661 - 663 1998

Directional characteristics of near infrared light in the process of radiation and transmission from wood Reviewed

S Tsuchikawa, M Torii, S Tsutsumi

JOURNAL OF NEAR INFRARED SPECTROSCOPY, VOL 6 1998 Vol. 6 page： 47 - 53 1998

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：NIR PUBLICATIONS

In this report, a newly designed apparatus, that is, a near infrared auto-goniophotometer, was introduced to acquire detailed optical information about biological material having a cellular structure like wood, Such information allows us to analyse the three-dimensional physical condition of a sample and confirm the suitability of proposed optical models. The directional characteristics could be found on the basis of the intensity of reflected or transmitted light at each observation angle,In these experiments, Sitka spruce (Picea sitchensis Carr,) with various thicknesses were used. Results of these measurements showed the directional characteristics which were affected significantly by the illumination conditions and sample thickness. Particularly, these varied characteristically with the wavelength of the incident light. This result supports the validity of the proposed optical models which vary with wavelength. Throughout these analyses, the relationships between the physical aspects of a sample and the emitted light from it is being clarified.

Non-traditional applications of near infrared spectroscopy based on the optical characteristic models for a biological material having cellular structure Reviewed

Adsorptive and capillary condensed water in biological material Reviewed

S Tsuchikawa, S Tsutsumi

JOURNAL OF MATERIALS SCIENCE LETTERS Vol. 17 ( 8 ) page： 661 - 663 1998

Adsorptive and capillary condensed water in biological material Reviewed

Tsuchikawa S., Tsutsumi S.

Journal of Materials Science Letters Vol. 17 ( 8 ) page： 661 - 663 1998

Tsuchikawa S.

Journal of Near Infrared Spectroscopy Vol. 6 ( 1-4 ) page： 41 - 46 1998

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

Non-destructive measurements, based on near infrared (NIR) spectroscopy, on biological material with a cellular structure like wood require a non-traditional approach. We have developed new concepts to model the optical properties of a sample having cellular structure, for the illumination conditions of the spectrometer available to us. A set of optical models, which consisted of the directional characteristics models, the light-path models and the equivalent surface roughness model was proposed to clarify the behaviour of light propagation in a wood sample. Furthermore, the mean optical path length, which was derived by incorporating the nth power cosine model of radiant intensity into the diffusion process model in consideration of the parallel beam component of incident light, was calculated. By introducing the concept of equivalent sample thickness, compatible with the mean optical path length, into the Kubelka-Munk theory, generalised input/output equations for radiation were constructed. In this non-traditional application of NIR spectroscopy, these optical concepts make it possible to analyse both the physical condition and chemical composition of a biological material with a cellular structure.

DOI： 10.1255/jnirs.119

Directional characteristics of near infrared light in the process of radiation and transmission from wood Reviewed

Tsuchikawa S., Torii M., Tsutsumi S.

Journal of Near Infrared Spectroscopy Vol. 6 ( 1-4 ) page： 47 - 53 1998

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Near Infrared Spectroscopy

In this report, a newly designed apparatus, that is, a near infrared auto-goniophotometer, was introduced to acquire detailed optical information about biological material having a cellular structure like wood. Such information allows us to analyse the three-dimensional physical condition of a sample and confirm the suitability of proposed optical models. The directional characteristics could be found on the basis of the intensity of reflected or transmitted light at each observation angle. In these experiments, Sitka spruce (Picea sitchensis Carr.) with various thicknesses were used. Results of these measurements showed the directional characteristics which were affected significantly by the illumination conditions and sample thickness. Particularly, these varied characteristically with the wavelength of the incident light. This result supports the validity of the proposed optical models which vary with wavelength. Throughout these analyses, the relationships between the physical aspects of a sample and the emitted light from it is being clarified.

DOI： 10.1255/jnirs.120

Non-traditional applications of near infrared spectroscopy based on the optical characteristic models for a biological material having cellular structure Reviewed

S Tsuchikawa

JOURNAL OF NEAR INFRARED SPECTROSCOPY, VOL 6 1998 Vol. 6 page： 41 - 46 1998

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：NIR PUBLICATIONS

Non-destructive measurements, based on near infrared (NIR) spectroscopy, on biological material with a cellular structure like wood require a non-traditional approach. We have developed new concepts to model the optical properties of a sample having cellular structure, for the illumination conditions of the spectrometer available to us. A set of optical models, which consisted of the directional characteristics models, the light-path models and the equivalent surface roughness model was proposed to clarify the behaviour of light propagation in a wood sample, Furthermore, the mean optical path length, which was derived by incorporating the n(th) power cosine model of radiant intensity into the diffusion process model in consideration of the parallel beam component of incident light, was calculated. By introducing the concept of equivalent sample thickness, compatible with the mean optical path length, into the Kubelka-Munk theory, generalised input/output equations for radiation were constructed. In this nontraditional application of NIR spectroscopy, these optical concepts make it possible to analyse both the physical condition and chemical composition of a biological material with a cellular structure.

Application of near infrared spectrophotometry to wood V. Calibration equations for physical conditions of wood Reviewed

Tsuchikawa S., Tsutsumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 43 ( 2 ) page： 149 - 158 1997.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

This paper is aimed at the non-destructive quantitative assessment of the physical conditions in bulky wood by near infrared spectrophotometry (NIRS). The calibration equations for the angles of the fibers to the direction of the incident light, θ, and the maximum height of surface roughness, R′y, were determined by a multiple linear regression analysis based on the NIR reflectance spectra. By taking the optical models into account, some sophisticated procedures to meet the situations are proposed, and the prediction error of these criterion variables are discussed. The results are summarized as follows. (1) The calibration equation for predicting θ performs enough to avoid the effect of surface roughness when the explanatory variable is selected suitably in the range of I (800-1400 nm). (2) After distinguishing whether θ is smaller or greater than 45° by the calibration equation for θ, θ is predicted accurately by suitably changing the partial regression coefficients. (3) The calibration equation for R′y is influenced characteristically by the combination of θ and wavelength λ of the explanatory valiables. R′y is predicted successfully by the partial regression coefficients corresponding to each local range of R′y. (4) For the normal measurement of NIR spectra, it is difficult to find a significant calibration equation for R′y at θ≧55°. Then, the absorbance may be measured by using a neutral density (ND) filter contacting the surface of the sample to capture more reflected light originating from the sub-surface structure.

Application of Near Infrared Spectrophotometry to Wood V. Calibration equations for physical conditions of wood Reviewed

Application of near infrared spectrophotometry to wood. V Reviewed

TSUCHIKAWA S

Mokuzai Gakkaishi Vol. 43 ( 2 ) page： 149 - 158 1997.12

Application of Near Infrared Spectrophotometry to Wood V. Calibration equations for physical conditions of wood

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 43 ( 2 ) page： 149 - 158 1997.2

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 43 ( 2 ) page： 149 - 158 1997.2

近赤外分光法による木材の非破壊計測(第5報)-試料の物理的構成に関する情報の検量線

"土川覚, 堤成晃,"

木材学会誌 Vol. 43 page： 149-158 1997.1

近赤外分光法による木材の非破壊計測(第5報)-試料の物理的構成に関する情報の検量線 Reviewed

土川覚, 堤成晃

木材学会誌 Vol. 43 page： 149-158 1997.1

Application of near infrared spectrophotometry to wood .5. Calibration equations for physical conditions of wood Reviewed

Tsuchikawa, S; Tsutsumi, S

MOKUZAI GAKKAISHI Vol. 43 ( 2 ) page： 149 - 158 1997

Application of near infrared spectrophotometry to wood .5. Calibration equations for physical conditions of wood Reviewed

Tsuchikawa, S., Tsutsumi, S.

MOKUZAI GAKKAISHI Vol. 43 ( 2 ) page： 149 - 158 1997

Application of near infrared spectrophotometry to wood II. Behavior of irradiated light in an aggregate of tracheids and directional characteristics of diffuse reflected and transmitted light Reviewed

Tsuchikawa S., Tsutsumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 42 ( 4 ) page： 343 - 353 1996.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

A series of experiments were made to apply Near Infrared Spectrophotometry (NIRS) to a non-destructive analytical method for wood. In this study, not only the determination of the compositions of materials, but also the acquirement of information relating to the physical aspects of them must be considered. Therefore, it is important to systematize the sequential propagation of light in wood, specifically, scattering, reflection, absorption, and transmission, which vary with the angles of the fibers to the directions of incident light, θ, and its wavelengths. In this study, a set of optical models, which consisted of directional characteristics models of light and light-path models, are proposed to clarify the behavior of light propagation in wood. For these models, the wood is taken as an aggregate of tracheids. The results are summarized as follows : (1) The behavior of light scattering in wood falls into three bands of the wavelengths of near infrared rays according to the trend of the absorption coefficient, K, and the scattering coefficient, S. (2) The directional characteristics models of diffusely reflected light and transmitted light, for which the aspects of K and S in three bands were taken into consideration, were proposed. (3) The light path model, which expresses the situation in regard to the emitted light from the aggregate-width of semi-infinite tracheids, is proposed. It can be found from the superposition of the light paths of diffusely reflected light at an arbitrarily chosen cell wall of semi-infinite tracheids. (4) The leakage ratio of diffusely reflected light from the aggregate-width of semi-infinite tracheids, S(θ), for various conditions of irradiation was calculated based on the optical models. These values were in good agreement with S(θ) found from the measurement value of absorbance and a second empirical equation. 2) (5) These results support theoretically the application of NIRS to a non-destructive analytical method for wood, which has some internal structure and definite order.

Application of near infrared spectrophotometry to wood IV.: Calibration equations for moisture content Reviewed

Tsuchikawa S., Torii M., Tsutsumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 42 ( 8 ) page： 743 - 754 1996.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

This paper is aimed at the nondestructive quantitative assessment of the moisture condition in bulky wood by using near infrared spectrophotometry (NIRS). In the first stage of a series of experiments, the effect of moisture condition on the minimum sample thickness in which light was diffuse-reflected sufficiently, d0, was investigated. Secondly, the calibration equations for moisture conditions of some species having homogeneous water distributions; moisture contents in percents (MC), and per unit volumes (MV), were determined by multiple linear regression analysis based on the NIR reflectance spectra. Furthermore, the prediction error of moisture content for a sample having an inhomogeneous water distribution was found by which the scope of the application for actual moisture conditions in wood was investigated. Similar experiments also were made for the model samples which represented the condition of inhomogeneous water distribution to grasp the effect of water distribution in wood on the prediction error of the calibration equations. The results are summerlized as follows. (1) d0 changes in general with the moisture conditions, and the trend of do with moisture conditions varies with the wavelengths, whereas they arise from the same compounds of water. (2) When the explanatory variables and the number of them are selected suitably for the calibration equations, they perform sufficiently in predicting the moisture conditions independently of the wood species. Especially, in the case of the explanatory variables selected from the 2nd derivative spectra, the prediction error is less than that from the original spectra in both the criterion variables of MC and MV. This is noticeable in the case of the calibration equation for MC. (3) For a sample having an inhomogeneous water distribution, it is important to select the wavelengths suitably as the explanatory variables in consideration of the minimum sample thickness in which light is sufficiently diffuse-reflected. (4) A model experiment was made in which the stepwise distribution of moisture content was given to the test pieces. The thickness of the surface-side part in a sample and the difference of moisture contents between the surface-side part and the back-side part in a sample govern the predicted values of the moisture contents and the features of which are made clear.

Application of near infrared spectrophotometry to wood III.: Behavior of reflected and transmitted light for parallel beam of incident light Reviewed

Tsuchikawa S., Tsursumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 42 ( 8 ) page： 733 - 742 1996.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

This study deals with the optical problems that arise when a parallel beam of near infrared light irradiates a sample with a cellular structure like wood. The behavior of reflected and transmitted light is explained by optical characteristic models of advanced expression based on the Kubelka-Munk theory. Through a series of experiments and examinations, it became clear that the behavior of transmitted light in wood was considerably different from that of an ideal scattering medium under the conditions of Lambert's cosine law. On the other hand, the behavior of diffusely reflected light in wood can be described by the Kubelka-Munk theory. Then, the diffusion process model in consideration of the component of a parallel beam of light was considered. Furthermore, the radiant condition of wood is described flexibly by the nth power cosine model of radiant intensity. Based on these optical characteristic models, the mean optical path length through the sample was calculated from which the concept of the equivalent thickness of the sample was derived. Over and above these, the generalized input/output equations for radiation were constructed by introducing the equivalent thickness of the sample into Kubelka-Munk's equations. The absorbance calculated by the generalized input/output equations for radiation agreed well with the experimental values. This result suggests that the behavior of near infrared light in wood can be described by them. The radiant intensity characteristics of the transmitted light varied with the conditions of light absorption in the near infrared Bands II and III (1400-2500 nm), and the scattering components perpendicular to the direction of incident light increased monotonically with decreasing wavelength in the Band I (800-1400 nm). For the nondestructive measurement of wood by near infrared spectrophotometry, it is very important to find the optimum conditions by considering the optical geometry of the apparatus, the wavelength of light, and the light scattering conditions in the sample.

Application of near infrared spectrophotometry to wood III.: Behavior of reflected and transmitted light for parallel beam of incident light Reviewed

Tsuchikawa S., Tsutsumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 42 ( 4 ) page： 343 - 353 1996.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

Tsuchikawa S., Tsursumi S.

Mokuzai Gakkaishi/Journal of the Japan Wood Research Society Vol. 42 ( 8 ) page： 733 - 742 1996.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

Near-infrared spectroscopy

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Nondestructive measurement of the subsurface structure of biological material having cellular structure by using near-infrared spectroscopy Reviewed

Tsuchikawa S., Hayashi K., Tsutsumi S.

Applied Spectroscopy Vol. 50 ( 9 ) page： 1117 - 1123 1996.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Spectroscopy

Biological materials - wood is a typical example - are widely used in a state where not only the cellular structure but also its bulky shape is retained. NIRS (near-infrared spectroscopy) may be called for as a promising technique to analyze the physical state of such materials as well as the chemical composition. In this report, the effects of physical conditions found in wood on the absorption of NIR radiation are examined. In the experiments, conifers (Sitka spruce) that had various degrees of surface roughness and different orientations of fibers to the direction of incident light were used. Results of these measurements showed that the orientation of fibers and the surface roughness of wood were directly related to the absorbance. In addition, it became clear that the behavior of diffusely reflected light in wood could be expressed by Kubelka-Munk theory and fell into three categories according to the characteristic of the absorption and scattering coefficient. On the basis of these results, a new concept for the behavior of NIR light passing through material made of hollow fibers has been proposed.

DOI： 10.1366/0003702963905114

Application of Near Infrared Spectrophotometry to Wood III. Behavior of reflected and transmitted light for parallel beam of incident light Reviewed

Near-infrared spectroscopy Reviewed

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S., Hayashi K., Tsutsumi S.

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S., Hayashi K., Tsutsumi S.

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

Near-infrared spectroscopy Reviewed

Tsuchikawa S, Hayashi K, Tsutsumi S

APPLIED SPECTROSCOPY Vol. 50 ( 9 ) page： 1117 - 1124 1996.9

近赤外分光法による木材の非破壊計測 (第4報) 含有水分に関する検量線

土川覚, 鳥居美里, 堤成晃

木材学会誌 Vol. 42 ( 8 ) page： 743 - 754 1996.8

Application of Near Infrared Spectrophotometry to Wood III. Behavior of reflected and transmitted light for parallel beam of incident light

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 42 ( 8 ) page： 733 - 742 1996.8

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 42 ( 8 ) page： 733 - 742 1996.8

近赤外分光法による木材の非破壊計測 (第4報) 含有水分に関する検量線 Reviewed

TSUCHIKAWA Satoru, TORII Misato, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 42 ( 8 ) page： 743 - 754 1996.8

Application of Near Infrared Spectrophotometry to Wood II. Behavior of irradiated light in an aggregate of tracheids and directional characteristics of diffuse reflected and transmitted light

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 42 ( 4 ) page： 343 - 353 1996.4

Application of Near Infrared Spectrophotometry to Wood II. Behavior of irradiated light in an aggregate of tracheids and directional characteristics of diffuse reflected and transmitted light Reviewed

TSUCHIKAWA Satoru, TSUTSUMI Shigeaki

Journal of the Japan Wood Researh Society Vol. 42 ( 4 ) page： 343 - 353 1996.4

Noestructive Measurement of the Subsurface Structure of Biological Material Having Cellular Structure by Using Near-Infrared Spectroscopy. Reviewed

"Tsuchikawa, S., Hayashi, K., and Tsutsumi, S.,"

Applied Spectroscopy Vol. 50 page： 1117-1124 1996.1

近赤外分光法による木材の非破壊計測(第2報)-近赤外照射光の仮道管群における挙動と拡散反射・透過指向特性 Reviewed

"土川覚, 堤成晃,"

木材学会誌 Vol. 42 page： 343-353 1996.1

近赤外分光法による木材の非破壊計測(第4報)-含有水分に関する検量線 Reviewed

"土川覚, 鳥居美里, 堤成晃,"

木材学会誌 Vol. 42 page： 743-754 1996.1

近赤外分光法による木材の非破壊計測(第3報)-平行入射光に関する反射光および透過光の挙動 Reviewed

"土川覚, 堤成晃,"

木材学会誌 Vol. 42 page： 733-742 1996.1

Noestructive Measurement of the Subsurface Structure of Biological Material Having Cellular Structure by Using Near-Infrared Spectroscopy. Reviewed

Tsuchikawa, S, Hayashi, K, Tsutsumi, S

Applied Spectroscopy Vol. 50 page： 1117-1124 1996.1

近赤外分光法による木材の非破壊計測(第4報)-含有水分に関する検量線 Reviewed

土川覚, 鳥居美里, 堤成晃

木材学会誌 Vol. 42 page： 743-754 1996.1

近赤外分光法による木材の非破壊計測(第3報)-平行入射光に関する反射光および透過光の挙動 Reviewed

土川覚, 堤成晃

木材学会誌 Vol. 42 page： 733-742 1996.1

近赤外分光法による木材の非破壊計測(第2報)-近赤外照射光の仮道管群における挙動と拡散反射・透過指向特性 Reviewed

土川覚, 堤成晃

木材学会誌 Vol. 42 page： 343-353 1996.1

Application of near infrared spectrophotometry to wood .2. Behavior of irradiated light in an aggregate of tracheids and directional characteristics of diffuse reflected and transmitted light Reviewed

Tsuchikawa, S; Tsutsumi, S

MOKUZAI GAKKAISHI Vol. 42 ( 4 ) page： 343 - 353 1996

Application of near infrared spectrophotometry to wood .4. Calibration equations for moisture content Reviewed

Tsuchikawa, S; Torii, M; Tsutsumi, S

MOKUZAI GAKKAISHI Vol. 42 ( 8 ) page： 743 - 754 1996

Application of near infrared spectrophotometry to wood .3. Behavior of reflected and transmitted light for parallel beam of incident light Reviewed

Tsuchikawa, S; Tsutsumi, S

MOKUZAI GAKKAISHI Vol. 42 ( 8 ) page： 733 - 742 1996

Tsuchikawa S, Tsutsumi S

MOKUZAI GAKKAISHI Vol. 42 ( 4 ) page： 343 - 353 1996

Application of near infrared spectrophotometry to wood .4. Calibration equations for moisture content Reviewed

Tsuchikawa S, Torii M, Tsutsumi S

MOKUZAI GAKKAISHI Vol. 42 ( 8 ) page： 743 - 754 1996

Application of near infrared spectrophotometry to wood .3. Behavior of reflected and transmitted light for parallel beam of incident light Reviewed

Tsuchikawa S, Tsutsumi S

MOKUZAI GAKKAISHI Vol. 42 ( 8 ) page： 733 - 742 1996

Application of near infrared spectrophotometry to wood .4. Calibration equations for moisture content Reviewed

Tsuchikawa S, Torii M, Tsutsumi S

MOKUZAI GAKKAISHI Vol. 42 ( 8 ) page： 743 - 754 1996

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Mokuzai Gakkaishi/Journal of the Japan Wood Research Society

Vibration Characteristics of a Rotating Circular Saw V. Effects of number of teeth and slots on vibration and radiated sound. Reviewed

MOKUZAI GAKKAISHI Vol. 40 ( 12 ) page： 148 1994

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .5. EFFECTS OF NUMBER OF TEETH AND SLOTS ON VIBRATION AND RADIATED SOUND Reviewed

H YOKOCHI, S KIMURA, S TUCHIKAWA

MOKUZAI GAKKAISHI Vol. 40 ( 2 ) page： 148 - 157 1994

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

Aerodynamically induced sound and the sound radiated from the resonating blade of an idling circular saw rotating at high speed were investigated experimentally.
The vortex groups were divided according to the Strouhal number and the number of the vortex groups depended on the number of teeth, while the circular saws without slot were not resonating.
The relationships between the rotation speeds and the aerodynamic sound pressures were divided into two groups. One group had 40 and 60 teeth, and the other group had 80 and 100 teeth. For the former, the stable vortex shedding generated because the gullets were large, and then the aerodynamic sounds were large. However, they became small while the saws were resonating. For the latter, the aerodynamic sounds were small while saws were not resonating, and they became very large while they were resonating. Aerodynamic sounds were the largest while saw with slots was resonating under the 8 nodal diameter and the slots antinodal vibration mode.
It was considered that the frequencies of vortex shedding locked-in the natural frequencies of the circular saws, and the vortex shedding at each saw tooth must synchronize with the traveling wave of a single vibration mode or a coupled vibration mode of the saws. Then, for the circular saws with the 40 teeth, the vortex shedding synchronized uneasily with the traveling wave, and the amplitudes of vibrations were small.
The radiation efficiency of circular saw blades is the ratio of sound energy to vibration energy. The radiation efficiency of the standing wave was greater than that of the forward traveling wave. That of the forward traveling wave was greater than that of the backward traveling wave.

Vibration Characteristics of a Rotating Circular Saw III. Non-limear vibration and coupled vibration Reviewed

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 1993

Vibration Characteristics of a Rotating Circular Saw IV. Non-linear resonant frequency Reviewed

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .3. NONLINEAR VIBRATION AND COUPLED VIBRATION Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 - 782 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .4. NONLINEAR RESONANT-FREQUENCY Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 - 787 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .3. NONLINEAR VIBRATION AND COUPLED VIBRATION Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 - 782 1993

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

A circular saw of slightly imperfect axial symmetry has two normal modes with slightly different natural frequencies. The purpose of this report was to clarify the fundamental non-linear vibration, coupled vibration, and the phase angle of the two vibrations, theoretically, and experimentally.
The following results were obtained:
1. The circular saw oscillated non-linearly with increases in membrane stress when the amplitude became large. The excited frequency at maximum amplitude was higher than a linear natural frequency, and the frequency range at large amplitudes became wide, and the amplitude collapsed after the maximum amplitude. A hysteresis phenomenon was induced upon increasing the excitation frequency and reducing it. The two vibrations were coupled when the amplitudes were large.
2. In the theoretical analysis, the two frequency responses were entirely different, in the case where the excitation frequency increased from the intermediate frequency between the two natural frequencies and in the case where it increased from the frequency that was lower than the lower natural frequency.
3. The coupled vibrations were excited, with the decrease of the interval between the two natural frequencies.
4. In the experimental analysis, under only the single excited frequency, the vibration with the natural frequency different than the exciting frequency became coupled to the exciting vibration with the phase angle +/-pi/2, when the amplitude became large.
5. Under the two excited vibrations, simultaneously with any phase angle between the two exciting forces, the phase angle between the two responding displacements converged +/-pi/2, and the two vibrations became coupled when the vibrations were excited non-linearly. As the phase angle between the two exciting forces closed to +/-pi/2, the coupled vibrations were excited in a wide range of frequencies.
6. With the rotating disk, it was considered that in the case where the exciting frequency equaled the backward traveling wave frequency, the vibration with the higher natural frequency predominated, and, in the case where the exciting frequency equaled the forward traveling wave frequency, the vibration with the lower natural frequency predominated.

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .4. NONLINEAR RESONANT-FREQUENCY Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 - 787 1993

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

Two types of coupled vibrations with the identical number of nodal diameters were excited during variable rotation speeds. One type (Mode I) was that the vibration was excited at slower rotation speeds, the amplitudes of the backward traveling wave predominated, and the phase angle between the two vibrations equaled -pi/2. The other type (Mode 111) was that the vibration was excited at faster rotation speeds, the amplitude of the forward traveling wave predominated, and the time phase angle equaled pi/2. The purpose of this report is to clarify the characteristics of non-linear vibration in the two types of coupled vibrations by measuring the saw-based frequencies and the amplitudes during the variable rotation speeds.
The following results were obtained:
1. With the rotation speed, the resonance frequency curve of Mode I differed from that of Mode III.
2. For each Mode, in the relationship between the compensation resonant frequencies that subtracted an increased frequency by the centrifugal stress from the original frequency and the amplitudes, the ideal and non-linear frequency response curve occurred without the jumping phenomena where the amplitudes rapidly increased and decreased. Under the vibration exciting by the forces based on air-vortex shedding, the frequencies of the air-vortex shedding had synchronized with the frequencies of the circular saw, and the excitation frequency changed like a self-excitation vibration in dependence on the vibration amplitude of a circular saw.
3. In the case of Mode III, the start frequency was lower than the lower natural frequency. The resonance frequencies were decided by the non-linear frequency response of the vibration of the lower natural frequency. The two vibrations became coupled with the same non-linear frequency response.
4. In the case of Mode I, the start frequency was higher than the higher natural frequency. The vibration of the higher natural frequency mainly was excited, and the resonance frequencies were decided by the non-linear frequency response of the vibration of the higher natural frequency.

Application of Near Infrared Spectrophotometry to Wood I. Effects of the surface structure Reviewed

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 1992

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO WOOD .1. EFFECTS OF THE SURFACE-STRUCTURE Reviewed

TSUCHIKAWA S, HAYASHI K, TSUTSUMI S

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 - 136 1992

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO WOOD .1. EFFECTS OF THE SURFACE-STRUCTURE Reviewed

S TSUCHIKAWA, K HAYASHI, S TSUTSUMI

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 - 136 1992

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

Near infrared spectrophotometry (NIRS) is a non-destructive analytical method to determine the composition of materials. Diffuse reflectance or an absorption spectrum over 800-2500 nm allows clear distinguishing of various organic compounds.
In this report, the effects of the surface structure of wood on the absorption of NIR rays are examined to take full advantage of this method. In the experiments, sitka spruce (Picea sitchensis (Bong.) Carr.), which had various surface roughnesses and orientations of the fibers in the direction of incident light, was used. The results are summarized as follows: (1) Absorbance decreases as the orientation of the fibers to the direction of incident light theta is increased. Such a tendency is more pronounced as the wavelength of interest becomes longer.
(2) The absorbance decreases with increasing surface roughness R'(max). A decrease in theta, or an increase in wavelength, raises the sensitivity of absorbance to R'(max). The relationship between absorbance and the surface roughness of wood can be expressed by the exponential equation labelled as the first empirical equation. Two constants in the equation depend on the wavelength and theta.
(3) Increasing the wavelength decreases the minimum thickness of the board in which light is completely diffuse-reflected. It is important to select the proper wavelength depending on the surface depth of interest.
(4) A semi-theoretical equation, labelled as the second empirical equation, is derived from a newly-proposed optical model, and it measures the values of absorbance. This model is composed of a theoretically equivalent membrane to the surface asperities and inclined square tubes of tracheids. It becomes clear that the thickness of the equivalent membrane should be some multiple of the maximum height of the surface roughness, and the amount of diffusely reflected light from the surface of the lumen is strongly dependent on theta and the wavelength.
(5) NIRS becomes a useful method for the detection of the physical conditions of wood.

Application of Near Infrared Spectrophotometry to the Determination of Fiber Orientation and Moisture Content of Wood. Reviewed

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 1991

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO THE DETERMINATION OF FIBER ORIENTATION AND MOISTURE-CONTENT OF WOOD Reviewed

TSUCHIKAWA S, HAYASHI K, TSUTSUMI S

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 - 760 1991

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO THE DETERMINATION OF FIBER ORIENTATION AND MOISTURE-CONTENT OF WOOD Reviewed

S TSUCHIKAWA, K HAYASHI, S TSUTSUMI

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 - 760 1991

Characteristics of the Vibration of Disks with Model Teeth and the Flows around the Disks I. Reviewed

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 1990

CHARACTERISTICS OF THE VIBRATION OF DISKS WITH MODEL TEETH AND THE FLOWS AROUND THE DISKS .1. RATIOS OF SPACE TO WIDTH OF SQUARE POLES Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 - 943 1990

CHARACTERISTICS OF THE VIBRATION OF DISKS WITH MODEL TEETH AND THE FLOWS AROUND THE DISKS .1. RATIOS OF SPACE TO WIDTH OF SQUARE POLES Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 - 943 1990

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

In our study, the characteristics of the vibration of a disk with model teeth, which were square poles, and the flow around the disk were investigated. Diameter and thickness of the disk were 305 mm and 2 mm, respectively. Width and height of square poles were 2 mm and 8 mm, respectively. The rotation speed was changed at intervals of 1 rps from 30 rps to 60 rps. The ratio (s/w) of the spaces (s) between the square poles and the widths (w) of the square poles ranged from 0.6 to 238.5.
The flow around the disk and the vibration of the disk were classified into five groups as follows: (1) In the range of 0.6 less-than-or-equal-to s/w less-than-or-equal-to 1.7, the shear layer tore off a square pole and reattached the next square pole. This reattachment excited the Complex Mode III (time phase angle pi/2). The exciting frequency became greater with a decrease of s/w.
(2) In the range of 2.2 less-than-or-equal-to s/w less-than-or-equal-to 3, the shear layer's reattachment and vortex shedding were compounded. A lock-in phenomenon, the same as the one in the range of 3 < s/w less-than-or-equal-to 5, almost was seen. Under the same nordal diameter, the resonant complex-modes changed their order; the first mode was III, the second one was I (time phase angle-pi/2), and the third one was III.
(3) In the range of 3 < s/w less-than-or-equal-to 5, the single voltex was eliminated. The Strouhal number (St) was approximately constant regardless of the s/w and the lock-in phenomenon introduced at the rotation speed where the voltex-shedding frequency equaled the natural frequency of the disk. The resonant complex-mode changed from I to III and shifted to the mode with a succeeding number of nodal numbers.
(4) In the range of 7 less-than-or-equal-to s/w less-than-or-equal-to 23, the multiple vortices were discarded. The number of vortices equaled the integer of s/3w. St decreased linearly with the increase of log (s/w). The resonant became difficult with the increase of s/w. In s/w = 15, the resonant occured only at the smaller number of vortices, and the resonant did not occur when s/w = 23. There were differences between the lock-in phenomena. At the smallest shedding frequency, Mode I resonated at a lower speed than the rotation speed at which the vortex-shedding frequency equaled the natural frequency of the disk, Mode III resonated at a higher speed than it, and no resonant was at it. At another, Mode III was apt to resonate at a lower speed than it.
(5) In s/w = 238.5, vortices generated, and spectra consisted of an assembly of spectrum lines at each rotation speed.