Country：Thailand

Country：Japan

Country：Japan

Country：Japan

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

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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

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PubMed

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

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PubMed

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

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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

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PubMed

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

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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

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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

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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

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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

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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

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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

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PubMed

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

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PubMed

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

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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

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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

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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

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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

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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

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

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

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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

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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

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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

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CiNii Research

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

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CiNii Research

Language：English  

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

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

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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

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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

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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

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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

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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

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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

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

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

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

DOI： 10.1016/j.foodhyd.2021.106627

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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

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

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

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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

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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

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

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

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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

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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

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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

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

DOI： 10.1016/jpostharvbio.2020.111417

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DOI： 10.37045/aslh-2021-0001

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

DOI： 10.1007/s10570-020-03508-9

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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

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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

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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

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

DOI： 10.1186/s10086-020-01874-3

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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

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

DOI： 10.1039/c9an01180c

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PubMed

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

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© 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

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CiNii Research

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

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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

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Scopus

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

DOI： 10.1515/hf-2018-0128

Scopus

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

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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

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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

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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

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

DOI： https://doi.org/10.1177/0967033518814851

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

Scopus

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

Scopus

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

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CiNii Research

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

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Scopus

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

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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

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Scopus

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

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CiNii Research

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

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Scopus

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

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

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

DOI： https://doi.org/10.1515/hf-2018-0060

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

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

Web of Science

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

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

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

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

DOI： 10.3389/fpls.2017.01937

Scopus

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

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

DOI： https://doi.org/10.1080/20426445.2017.1378398

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

DOI： 10.1080/20426445.2017.1378398

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Scopus

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

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

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

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

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

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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

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

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

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

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

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

DOI： https://doi.org/10.1371/journal.pone.0176920

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

DOI： 10.1371/journal.pone.0176920

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PubMed

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

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

<p>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.</p><p>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.</p>

DOI： 10.2524/jtappij.71.326

CiNii Research

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

DOI： 10.2524/jtappij.1603

CiNii Research

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.

Scopus

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.

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.

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.

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.

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.

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.

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.

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.

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

DOI： 10.1255/jnirs.1256

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Scopus

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

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Scopus

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

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PubMed

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

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Scopus

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

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PubMed

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

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

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Scopus

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

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

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

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

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

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

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Scopus

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

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Science Support Foundation  

DOI： 10.5363/tits.21.2_66

CiNii Research

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

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Scopus

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

Scopus

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

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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

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Scopus

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

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Scopus

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

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Scopus

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

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

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

DOI： doi: 10.1255/jnirs.1174

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

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

Web of Science

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

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Scopus

CiNii Research

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

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.

Web of Science

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

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

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Scopus

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

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Scopus

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

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PubMed

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

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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

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Scopus

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

Web of Science

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

DOI： 10.5558/tfc2013-103

Scopus

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CANADIAN INST FORESTRY  

Web of Science

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

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

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PubMed

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.

Web of Science

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

Scopus

Web of Science

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

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Scopus

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

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

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

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

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

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

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

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

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

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

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

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

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Scopus

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

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Scopus

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

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

Web of Science

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

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

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

CiNii Research

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

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

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

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

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

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

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Publisher：日本木材加工技術協会  

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：日本木材加工技術協会  

CiNii Research

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

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Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

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

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

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

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

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

CiNii Research

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

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

Authorship：Lead author   Language：Japanese  

Language：English  

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

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

Publisher：Springer  

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

CiNii Research

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

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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.

Scopus

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.

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.

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.

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.

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.

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.

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.

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

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

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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.

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

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 onetime crosscutting. © Forest Products Society 2010.

DOI： 10.13073/0015-7473-60.3.244

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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.

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DOI： 10.1366/000370210790572016

PubMed

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

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

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

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

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

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

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

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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

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

CiNii Research

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

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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

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

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&apos;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&apos;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&apos;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.

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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

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Publishing type：Research paper (scientific journal)  

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

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

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.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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. © 2009 Society for Applied Spectroscopy.

DOI： 10.1366/000370209787599004

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

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

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

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

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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.

Scopus

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.

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.

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.

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.

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.

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.

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.

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

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&apos;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&apos;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&apos;s modulus with hydrothermal treatment was governed by two main components, that is, depolymerization of polysaccharides and variation of cellulose crystallinity.

Web of Science

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

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Publishing type：Research paper (scientific journal)  

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

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.

Web of Science

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.

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：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. © 2008 Society for Applied Spectroscopy.

DOI： 10.1366/000370208785284295

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PubMed

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

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Web of Science

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

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PubMed

Publishing type：Research paper (scientific journal)  

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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

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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

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PubMed

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

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

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

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

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

時間飛行近赤外分光法を果実の光計測に応用し、内部品質評価の可能性を検討した。学内共同研究者：倉田洋平、池本有香

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

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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

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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

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

Web of Science

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

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PubMed

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.

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

CiNii Research

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

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

Authorship：Lead author   Language：English  

本論文は、1990年代以降急速に広まった木材科学・工業分野への近赤外分光法の適用事例を網羅的に紹介した総説形式のものである。約150の文献が、詳細に紹介されている。

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

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Publisher：Near-Infrared Spectroscopy in Food Science and Technology  

DOI： 10.1002/9780470047705.ch4

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Publisher：Near-Infrared Spectroscopy in Food Science and Technology  

DOI： 10.1002/9780470047705.ch4

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Near-Infrared Spectroscopy in Food Science and Technology  

DOI： 10.1002/9780470047705.ch5

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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

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Publisher：Springer  

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

CiNii Research

Web of Science

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

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PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC 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.

Web of Science

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

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

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

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

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

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

CiNii Research

本論文では、重水素置換法と近赤外分光法を組み合わせた新しい手法によって、木材の経年劣化様式を分子レベルで詳細に観察し、細胞壁内におけるセルロースミクロフィブリル間の間隙寸法のオングストロームオーダの経年変化状況を把握することに成功した。これによって、NIR-Archeometryとも呼ぶべき新しい考古計測学手法の基盤が確立された。

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

Scopus

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.

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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

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PubMed

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

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

CiNii Research

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

CiNii Research

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

CiNii Research

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

CiNii Research

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

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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.

Scopus

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

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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

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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

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

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

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

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

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

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本論文では、光伝播の強度・時間変化をナノ秒オーダで詳細に把握することによって、試料内部情報を非破壊で検出する時間飛行近赤外分光法（TOF-NIRS）を世界で初めて提案するとともに、これをリンゴの糖度・酸度検出に適応し、既存の手法では達し得なかった精度で推定可能となることを示した。

Publisher：Gifu University  

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

CiNii Research

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