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In order to extend the application of bamboo-based products in the field of construction, this study reports on a preliminary experimental evaluation of the behavior of sheathing-to-framing connections comprised of bamboo oriented strand board (BOSB) and glued laminated bamboo (GLB) and the applicability of the load–displacement model to the GLB–BOSB connections. Different dowel types and edge distances were considered in monotonic tests. In order to conduct a direct comparison of the behavior of the BOSB connection to plywood and oriented strand board (OSB) sheathing in shear walls, three panels for sheathing were subjected to monotonic and cyclic tests. The results indicated that different types of dowel affected significantly the lateral resistance performance of GLB–BOSB connections. The hex head self-tapping screw joint had stiffer and stronger lateral resistance performance but lower deforming ability. In addition, the edge distances of fastener joints significantly influenced the lateral load carrying capacity. The results of monotonic and cyclic tests of the three sheathing panel connections indicated that BOSB panels showed a pattern of superior lateral load capacity, and the energy dissipation by BOSB joints was greater than that of OSB and plywood connections with the same framing prior to the damage. Furthermore, the exponential prediction equation modeled the shape of experimental curves with reasonable accuracy that was applicable to GLB–BOSB connections.

Bamboo is a natural bio-composite material that is both tough and possesses excellent mechanical properties. Its delicate structure and fiber arrangements play an important role in the mechanical properties and the fracture performance of bamboo. In this study, the fracture behaviors of bamboo due to tensile strength and bending were investigated using synchrotron radiation micro-computed tomography and environmental scanning electron microscopy (ESEM). Both tension and bending tests revealed that fibers are the key factors for bearing extra load and impeding crack propagation. Crack paths were found to be different in bamboo strips with different fiber percentages, and the interface between pulled-out fiber bundles and fiber break (in helix breaks and shearing break) was observed to be typical fracture characteristics in tension. Moreover, advanced micro-matrix cracking, interface debonding, fiber bundle bridging and the splitting of cell wall layers were found to be important fracture characteristics in bending. Both in tension and bending, a reasonably weak interface appeared to be beneficial for improving fracture toughness of fiber-reinforced bamboo. Thus, it is clear that “fiber bridging” mechanisms and “shear-lag theory” are well exhibited in bamboo.

A 1D anharmonic chain with a single impurity particle is used to study the center deviation and stability of the localized modes. The displacement patterns of the localized modes for a variable impurity mass and anharmonic parameter are studied. The pattern center is shifted away from the impurity with decreasing anharmonic parameter for both symmetric and asymmetric anharmonic impurity modes. In the limit of a heavy-mass impurity, the energy localization is constrained to the three particles nearest to the impurity.

Experiments have been performed to study the chaotic dynamics of a ball bouncing on a vertically vibrating plate. The velocity dependence of collision duration and coefficient of restitution is determined, and phase portraits of chaotic structures for the flight time and the relative collision velocities are obtained. Numerical calculations are carried out to examine the effects of velocity-dependent collision duration on the ball dynamics. It is revealed that when the collision is instantaneous, sticking solutions are always observed, whereas when the collision duration is taken into account, sticking solutions are destroyed and thereby chaos behaviors are induced.

The present work aims to determine the impact performance of two bamboo-based laminated composites [bamboo/poplar laminated composite (BPLC) and bamboo/glass fiber laminated composite (BGFLC)] using low-velocity impact tests by a drop tower. In addition, fracture characteristics were evaluated using computed tomography (CT). Results showed that BPLC presented better impact properties in both directions than BGFLC. Three stages are noted in impact load–deflection curves. The load–deflection curve characteristics of two composites are different in different stages. Matrix cracking, fiber-matrix interface debonding and delamination, and fiber breakage are the three main fracture mechanisms of two composites. Structural characteristics of the components and bonding strength are the important factors for impact properties and fracture mechanism of both bamboo-based laminated composites.

As a construction material, the phenomenon of creep is critical to bamboo structural design. The present work investigates variation of flexural creep behavior of bamboo (Phyllostachys pubescens) in its radial direction. Bamboo specimens were divided into two groups, half of the specimens were loaded by the green side, which fiber-rich outer culm wall was in compression (A); the other half were loaded by the yellow side, which fiber-rich outer culm wall was in tension (B). The specimen in both groups were cut into three sections along radial direction, the outer part (A1, B1), the middle part (A2, B2), and the inner part (A3, B3). All specimens were conducted to a 24 h-creep tests. The results show that: The creep resistance of outer part of bamboo is favorable, no matter which kind of loading way. Compared to type A loading with fiber-rich part, specimens of type B loading with fiber-less part showed a higher creep residual strength. The fiber volume fraction was linearly associated with the initial creep of type A and the final creep of type B. It mainly related to the feature and distribution of fiber and parenchyma.

The remarkable fracture toughness of bamboo culms is highly attributed to the proper embedding of the stiff fibre caps of the vascular bundles into the soft parenchyma matrix. In this study, the fracture behaviour of small specimens of moso bamboo (Phyllostachys pubescens) in tension and bending were investigated in situ with a scanning electron microscope (SEM) to visualise crack initiation and propagation within bamboo tissues and its interactions with the structural components (fibres and parenchyma tissues). Fracture surfaces were studied by field-emission SEM. The fracture of bamboo in either tension or bending was non-catastrophic, and cracks propagated in a tortuous manner with massive interfacial delamination. The stiff fibre bundles played an important role in restraining crack propagation, acting as bridges to inhibit cracks opening and also as “crack stoppers” inducing extensive crack-deflections. Microstructural analysis of the fractured surfaces revealed that substantial interfacial debonding, sliding and fibre pull-outs occurred at various length scales, which are believed to be effective in dissipating the crack energy. The synergistic effects of crack-deflection, crack-bridging and interfacial debonding are regarded to be mainly responsible for the remarkable fracture toughness of bamboo.

The collision characteristics of a ball impacting on a vertically vibrating plate are different from those normally presented in the ball-ball or ball-plate collision, because the vibration of the plate inevitably gets involved in the collision process. We experimentally study the behavior of a steel ball bouncing on a vertically vibrating plate, and determine the dependence of the coefficient of restitution and the collision duration on the impact velocity. In the experiment, a double-layer composite structural plate is used, which is formed by gluing a piece of polyethylene onto a stainless steel sheet. It is found that the vibration of the plate makes the coefficient of restitution to be no longer a single-valued function of the impact velocity, but rather multi-valued, and exhibit a complex but regular dispersion structure. To account for such dispersion structure, a collision dynamics model is developed in which the inertial force due to the vibration of the plate is included. The energy loss caused by viscous deformation and inertial force is analyzed. Both the coefficient of restitution and the collision duration calculated by this model agree well with the experimental ones.

The parenchymal cells in bamboo are an attractive source of raw materials due to their low degree of lignification and relatively loose cell wall structures. In this study, nanocellulose fibrils (NCFs) were isolated via a combined process of ultrasonication and chemical pretreatment of parenchymal cells separated from Moso bamboo (Phyllostachys pubescens) by means of a simple screening approach. As indicators of the fibrillation degree served the morphology, optical properties, and dynamic viscosity of the prepared NCF hydrogel as function of ultrasonication time. The mechanical properties of NCF derived films were also determined. The results show that high-quality NCFs can easily be prepared from bamboo parenchymal cells through the above-mentioned process, with an optimal ultrasonication time of 40 min. The utilization of bamboo processing residues via the ultrasonication route is promising and for energy saving production of high-quality NCFs at large scale.

A 1D anharmonic chain with a single impurity particle is used to study the vibrational energy localization. Numerical and asymptotic solutions for the symmetric anharmonic localized mode are both presented. The numerical results reveal that the energy localization strengthens with decreasing impurity mass or with increasing anharmonicity. In the weak-anharmonicity limit, the energy localization is close to the harmonic results and varies linearly with respect to the anharmonicity parameter. In the strong-anharmonicity limit, the localized structure tends towards a constant value that is independent of anharmonicity, but as a function of impurity mass. We finally analyze the stability of this symmetric impurity mode, and evidence a stable asymmetric mode as the result of a bifurcation from the symmetric mode for the case of the large impurity mass.

Pollen Typhae total flavone (PTF), the extract from Pollen Typhae, is reported to enhance glucose uptake in C2C12 myotubes in vitro, but the convincing evidence is lacking in vivo. In this study, PTF ameliorated insulin resistance and dyslipidemia, but failed to significantly increase body weight in type 2 diabetic rats induced by high-fat diet and low-dose streptozotocin.

We investigated the effects of interstitial air on the impact bifurcations of period doubling motion in vertically vibrated grains beds. The impact of grains on the container bottom undergoes a series of subharmonic bifurcations as the vibration intensity increases. With the presence of air, the vibration acceleration of the bifurcation points caused by the air drag on grains increases as the size of grains decreases. Especially, for grains with sufficiently small diameters, higher-order bifurcations become unobservable. We also found that with the decrease of the grains size, the dependence of the bifurcation points on the size of grains and vibrating frequency becomes more obvious due to the air drag, and such a dependence disappears when a vacuumed or porous-bottomed container is used.

The present work is aiming at the elucidation of the tensile behaviour and fracture performance of moso bamboo (Phyllostachys pubescens Mazei ex H. de Lebaie) by means of digital speckle correlation method (DSCM) and microscopic techniques. Results indicated that fibres play a major role in longitudinal tension and impeding crack radial propagation. Hybrid I-II failure mode was observed, i.e., crack opening (in tensile stress) and shear sliding (in shear stress). According to microscopic fracture characteristics, fibres extraction and stretching, filament formation in parenchyma with fibres bridging, interface debonding and the helix fracture of fibres happened in tension, which created more interfaces and dissipated more energy. The graded composite structure of bamboo provides intrinsic and extrinsic toughening mechanisms which contribute to improved toughness and physical properties.

This paper reports the manufacturing process for biodegradable paper sheeting with incorporation of bamboo paper sludge, fibers of poplar woods, and viscose fibers by wet-laid nonwoven technology. The best process conditions included a basis weight of 30 g/m2, a bamboo paper sludge content of 10 wt%, and a polyvinyl alcohol concentration of 4 wt%. The burst strength, tearing resistance, tensile properties, resistance to water, and degradation rate were 220.65 kPa, 60.00 N, 46.10 N, 153 Pa, and 56.18%, respectively, under the best process conditions. The biodegradable paper sheeting can satisfy the demand for replacement of agricultural plastic sheeting used for such purposes as moisture retention of soil and promotion of plant growth.

Through chemical composition analysis, scanning electron microscope observation, stain-fungi isolation from stained canes and their inoculation on unstained canes, as well as xenon light aging study, causes of Daemonorops margaritae cane’s discoloration were investigated. Results show that the yellow discoloration is mainly chemical photo-induced and the blue, brown and red stains are mainly resulted from the stain-fungi’s mycelia colors or secreted pigments. A treatment with hydrogen peroxide solution as main bleaching agent was explored. All the above discoloration could be effectively removed and renewed to be attractive lustrous yellowish.

Laminated bamboo composite (LBC) has received a great attention due to its environmental friendly characteristics and excellent physical and mechanical properties, therefore it is necessary to investigate the durability of the LBC material in ambient environment (temperature and relative humidity). In this paper, firstly, LBC materials were manufactured in laboratory. Moisture absorption and thickness swelling kinetics of the materials at different temperatures and relative humidity were investigated. Then effects of ambient environment on mechanical properties were evaluated at three different ambient temperatures (21 °C, 36 °C, and 60 °C) and different moisture contents. It is found that the moisture absorption and the thickness swelling increase with temperature, relative humidity and ageing time before an equilibrium condition is satisfied. Parameters of the diffusion coefficient and the swelling rate increase with the temperature. In addition, there is a significant decrease in mechanical properties of the moisture-saturated specimens compared to the dry ones. And the degradation of the bending property and the compressive strength is found to be a function of the moisture absorption during the initial period and becomes stable as the absorption process approaches equilibrium. Finally, surface erosions are shown by scanning electron microscopy (SEM) after the hydrothermal aging at 60 °C.

The objective of this work was to use a novel 3-D test analysis system for evaluating the mechanical properties of the natural fiber fabric composites under biaxial loads. Composites with three resin matrices (water-based epoxy resin, isocyanate resin, phenolic resin) were investigated, and strain filed were characterized by using the digital speckle correlation. The water-based epoxy resin plate and isocyanate resin plate demonstrated a characteristic of orthotropy and elastoplasticity, while the phenolic resin board revealed linear elastic and brittle-fracture simultaneously at X,Y-axial. Dissimilarities of biaxial load value were related to the orthotropy of composite structure, and load changes in fracture direction had a negative effect on the other directions at breaking moment. The degrees of dropping presented a positive correlation with the load values at rift direction. Under the linear elastic stage, the value of load and average strain at Y-direction were larger than that under X-direction within the same testing area. The strain-filed at X/Y-direction provided by isocyanate and phenolic resin plates illustrated a more smooth change than that of the water-based epoxy resin plate.

To evaluate the mechanical properties of natural fiber fabrics with the characteristic of interweaving between warp and weft direction as well as textile structural composites under complex stress state, it is essential to develop experimental techniques to realize multi-axial testing for large deformation. This work proposes a novel testing device for investigating fiber fabrics and textile composites under multidimensional loads. Accuracy of the system is comparable to the testing diagnostics of the Instron 5808 previously. The homogeneity for different types of cruciforms and different biaxial tensile speeds were investigated. The effects of different loading methods, biaxial (X and Y), and 3-D loading (X, Y, and Z) on the breaking strength of the woven ramie fabric were presented. The displacement-field and shear field for composites with hole were characterized by the digital speckle correlation method.

It has been repeatedly observed that the mechanical properties of microtomed wood sections are significantly lower than those of samples of normal size, but few investigations have been conducted to deal with this topic, especially based on theoretical approaches. We measured the longitudinal MOE of Chinese fir on microtomed sections ranging in thickness from 70 to 200 µm and compared these with the values of samples of normal size. The results indicate that the MOE of microtomed wood sections increases with thickness from 70 to 200 µm, but is significantly less than that of normal samples. A size effect coefficient of 2.63 is inferred based on statistical data for samples of normal size and 200 µm thick microtomed sections. Finally, an explanation based on a complete shear restraint model of cell walls and a single fiber multi-ply model is proposed for the size effect on stiffness of microtomed wood sections.

The objective of this preliminary study was to partially replace phenol in the synthesis of phenol-formaldehyde resin with feather protein. Feather protein-based resins, which contained one part feather protein and two parts phenol, were formulated under the conditions of two feather protein hydrolysis methods (with and without presence of phenol during hydrolysis), two formaldehyde/phenol molar ratios (1.8 and 2.0), and three pH levels (9.5, 10.5, and 11.5). Southern pine fiberboard bonded with feather protein-based resins was fabricated and bending strength, bending stiffness, internal bonding strength, and percent thickness swell were evaluated. Results indicated that the test parameters all significantly affected resin quality. The resin formulated with feather protein hydrolyzed in the presence of phenol, using a F/P ratio of 2.0, and at a pH of 10.5 performed as well as the neat PF resin. Based on our findings, feather protein is a potential cost-effective material for the production of PF-type adhesive resins.

The development of wet heartwood was studied in relation to different tree spacings (2×5 m, 4×5 m, 4×10 m) in a 28-year-old Populus xiaohei T.S. Hwang et Liang in China. Stem discs of 5 cm thickness were taken every 2 m from the stump to the top (including the 1.3 m height), and wet heartwood area was measured for each section. Results indicated that wet heartwood was present in all sample trees, and represented a substantial part of the stem, accounting for nearly 62.0%, 56.0% and 65.2% of tree stem volume, respectively, for spacings 2×5 m, 4×5 m and 4×10 m. Wet heartwood tapered towards the top of the tree, closely following the stem wood profile. This vertical distribution pattern of wet heartwood was scarcely influenced by spacing. However, wider spacing resulted in larger wet heartwood area and volume, and the production of wet heartwood was positively and significantly correlated with tree diameter. Estimation of wet heartwood volume from external tree characteristics was possible using var...

Crystallinity is an important property of woody materials; it responds to tree growth traits, structure, and chemical composition, and has a significant effect on Young’s modulus, dimensional stability, density, and hardness, etc. The ability of near-infrared (NIR) spectroscopy coupled with multivariate analysis to rapidly predict the crystallinity of slash pine (Pinus elliotii) plantation wood was investigated. The results showed that the NIR data could be correlated with the X-ray diffraction (XRD)-determined crystallinity of slash pine wood by use of partial least squares (PLS) regression, producing excellent coefficients of determination, r2, and root mean square error of calibration, RMSEC. The use of either reduced spectral ranges or the selection of certain wavelengths consistent with known chemical absorptions did not have any detrimental effect on the quality of PLS models allowing the use of inexpensive, small, and portable spectrometers. These studies show that NIR spectroscopy can be used to rapidly predict the crystallinity of slash pine wood.

There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Regression models for predicting the individual stem volumes of Populus xiaohei were established using extracted crown width, as well as estimated tree parameters (i.e. diameter at breast height [DBH] and tree height) as predictors. Our results indicated that crown width could be accurately extracted from QuickBird images using a multi-scale segmentation approach with a mean relative error of 5.74%, especially for wide-spacing stands. Using either extracted crown width alone or with estimated DBH and tree height can successfully estimate individual stem volume of Populus xiaohei with the R2 value ranging from 0.87 to 0.92 depending on different model forms. In particular, the two second-order polynomial models (model 2 and model 6), based on QuickBird image-derived crown widths and estimated DBH and tree heights, respectively, were the best at describing the relationship between stem volume and tree characteristics.

Morphological features and anatomical variations are described and illustrated in detail for four native species of Leguminosae grown in arid sandy regions in China, which are Hedysarum scoparium Fisch.et Mey., Caragana korshiskii Kom., Lespedeza bicolor Turcz. and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. All species showed similar morphological features: distinct growth ring boundaries, ring to semi-ring-porosity, simple perforation plates, alternate intervessel pitting, nonseptate fibers, paratracheal confluent axial parenchyma, helical thickenings and heterocellular rays. However, the vessel arrangement and their quantitative features were different. A. mongolicus had smaller vessel diameters and larger vessel frequency, while the values in the other three species were similar, but bigger than those in A. mongolicus. The variation of vessel lengths and fiber lengths along a horizontal direction showed an irregular tendency. There were significant differences in both fiber lengths and vessel element lengths among trees and within trees, except for A. mongolicus. The relationships between anatomical features of secondary xylem and the adaptability of these species to desert environments are also discussed.

Summary This study develops a method to theoretically calculate ovendry softwood resistance and resistivity based on block transformation theory. The resistance of a single cell was calculated as the sum of a combination of serial and parallel connections of the two end cell walls, four side cell walls and cell cavity. One cell was considered as a resistor, and the wood as a network of single cell resistors. Resistance was calculated for a group of four resistors. After several iterations, the total resistance of wood was obtained. To test the model, experiments were conducted on Masson pine specimens. The resistances of fifty specimens were measured and their resistivities calculated. A comparison of the theoretical calculations and the measured results revealed a difference between the measured average resistivity of specimens and the model calculations of less than 8%. The resistivity of softwood was found to relate to the size of wood cells, amount of ray cells and the percentage of latewood.

Rosewood is a kind of precious wood which include many wood species. It's difficult to most people to identify rosewood species. Near infrared spectroscopy (NIR) of eight rosewood species was investigated in the present paper. The results showed that (1) there was significant correlation between near infrared spectroscopy and color parameters expressed by L*, a* and b* values of rosewood, the correlation coefficients between NIR predicted and laboratory measured L* , a* and b* values were 0.988, 0.991 and 0.993, respectively; (2) The eight rosewood samples can be distinctly divided into eight categories by principal component analysis (PCA), the differences in the NIR among the eight rosewood species were more distinctly revealed by the three-dimensional PCA score plot than that of the two-dimensional. The results illustrated that it was feasible to identify rosewood species by near infrared spectroscopy coupled with chemometrics, and also provided a new method to rapidly identify or classify rosewood.

CT is widespread non-destructive detection technique for wood materials, and the density measurement is a key role during this application. In the present report, the use of CT for air-dry density measurement of wood and bamboo is described. The authors found that there were marked linear correlations between air-dry density (0.303-1.061 g x cm(-3)) of 24 kinds of woods and their respective CT value, as well as 25 kinds of lignin materials (including 24 kinds of woods and 1 kind of bamboo) and the CT value, both with correlation coefficient of 0.99, which belonged to the CT technological breakthrough for wood quantitative detection These research results show that CT is an appropriate way to measure density for wood and bamboo, and would provide technical support for CT used in the field of wood science research and wood processing.

The structures and qualities of main chemical compositions in cell wall of bamboo treated with gamma rays were tested by nuclear magnetic resonance spectrometer (NMR) and X-ray Diffraction (XRD). The result indicated that the bamboo crystallinity increased at the beginning of irradiation process, while the crystallinity reduced when the irradiation dose was raised to about 100 kGy. During the whole irradiation process, hemicellulose degraded, and with the irradiation doses increased the non-phenolic lignin changed to the phenolic.

The lignin distribution in different anatomical regions of developing moso bamboo Phyllostachys pubescens f. lutea Wen was investigated by means of optical microscope and visible-light microspectrophotometry coupled with the Wiesner and Maule reaction. The lignin is widely distributed in different tissues, in which there is a difference in lignin content between different ages, tissues and anatomical regions. Guaiacyl lignin and Syringyl lignin unit can be found in cell wall of fibre, parenchyma and vessel. Lignin content of secondary wall, cell corner and compound middle lamellae of fibre increased gradually within 12 months, then almost remained in the same level or decreased slowly in the culms with an age from 12 to 78 months. The lignification rate in secondary wall, cell corner and compound middle lamellae of fibre changed with age until they reached a relative steady value. There is no regular variation in lignin content with different radial location of culms and different location in fibre strands within one age. The secondary wall, compound middle lamellae of parenchyma and vessel secondary wall lignified rapidly within 12 months, and then changed slowly.

In order to find the relationships between the crystal size and the physicalmechanical properties, and to improve the levels of high value-added processing and utilizing for Chinese rattan resources, the daemonorops margaritae, Chinese unique rattan, was chosen as the research material, then the crystal size was measured and analyzed through the X-ray diffraction method before and after gamma-ray irradiation. The results show that the crystal width is in the range between 1.901 and 3.019 nm, and the average width is 2.403 nm. The crystal length is in the range between 4.118 and 28.824 nm with an average length of 10.907 nm. After irradiation, the width of daemonorops margaritae is in the range between 2.139 and 3.540 nm, and the average width is 2.569 nm, and the crystal length dramatically changes in the range between 5.765 and 38.432 nm with a mean of 15.530 nm. Both of the scope and the mean value of the crystal width and length increase after irradiation.

In order to find out the properties and improve the levels of high value-added processing and utilization of Chinese rattan resources, the Daemonorops Margaritae, a Chinese unique rattan, was chosen as the research material, then the microfibril angles (MFA)crystallinity index (CrI) were measured through the X-ray diffraction method, and the effects of gamma-ray irradiation upon the MFACrI were analyzed. The results show that the MFA of the cane varied from 33.4 degrees to 38.7 degrees with the average value of 36.1 degrees, and the MFA of the coretex were not larger than that of the core. The MFA were 36.2 and 35.8 degrees, 35.9 and 35.4 degrees, and 36.2 and 35.4 degrees before and after irradiation with a radiation dose rate of 2.5 x 10(3) Gy x h(-1) and radiation dose of 3, 9 and 15 kGy, and decreased 1.10%, 1.39% and 2.21% respectively compared with the former. The CrI was in the range of 24.8%-32.0%, and the average CrI was 28.6%. The CrI of coretex was larger than that of the core. Under the same radiation conditions, the CrI was 28.1% and 26.0%, 28.1% and 26.9%, and 28.5% and 27.1% before and after irradiation, and the latter decreased 7.58%, 4.34% and 4.70% respectively compared to the former. With the radiation dose of 3 kGy, the differences in CrI between with and without irradiation were most notable in the 0.001 level.

Metal elements, especially the heavy metal element, need to be considered for resource utilization of paper sludge. Seventeen kinds of metal elements were determined by ICP-AES method, which were form two kinds of paper sludge from Anhui Shanying paper mill, one kind of paper sludge from Fujian Qingshan paper mill, and one kind of paper sludge from Fujian Zhongzhu paper mill. The results show that there are different amounts of metal elements in the 4 kinds of paper sludge including poisonous metal elements, such as Cr, etc, metal element which is poisonous when excessive, such as Fe, etc, and P and K which are beneficial for plant growth Al and Ca contents are maximal. The recovery ratio for Fujian Zhongzhu paper mill obtained by standard addition method is 94.4%-107.3%. Heavy metal elements content lower than the national standard GB/4284-84 "Control standards for pollutions in sludge form agricultural use". The order of heavy metal elements content is paper sludge from Fujian Zhongzhu paper millpaper sludge from Fujian Qingshan paper millpaper sludge from Anhui Shanying paper mill. The results provide theoretical directions for resource utilization of paper sludge, especially for agricultural utilization and land utilization

Extensive research has demonstrated that near infrared spectroscopy (NIR) and partial least squares discriminant analysis (PLS-DA) can be used to rapidly discriminate or detect a wide variety of food, medicine and agricultural products. The use of NIR coupled with PLS-DA to detect wood biological decay was investigated in the present paper. The results showed that the correlation between the predicted category variable of calibration and validation and the measured category variable is significant with a correlation coefficient (r) over 0.94 and low SEC and SEP (0.17); the discriminant accuracy for the non-decay, white-rot and brown-rot decay samples are 100% (deviation0.5) by the PLS-DA model based on the test set of samples; the discriminant accuracy by PLS-DA model is better than that by SIMCA model. It's suggested that NIR spectroscopy coupled with PLS-DA could be used to rapidly detect wood biological decay.

Lignin is one of the main components of lignocellulosic materials. The main purpose of wood cooking and bleaching is to remove lignin by chemical agent in paper industry. Whereas the lignin content shows wide variations depending on its tree specie, site condition, part and so on, it is essential to analyze the lignin content of different raw material. The aim of this paper is to develop a rapid near infrared (NIR) reflectance spectroscopic method to characterize the Klason lignin content of bamboo. Fifty four samples from three growth years, two positions along the longitudinal directions and three positions along the radial directions within a bamboo pole were prepared. The Klason lignin contents of 54 samples were analyzed according to traditional chemical method, the spectra of these samples were collected by NIR in the range of 350 to 2500 nm, and the relationship between the lignin content and the spectra of these samples was established by multivariate statistical technique. After second derivative pretreatment of raw spectra, the Klason lignin contents of the bamboo samples were quantified using partial least-squares statistical analysis (PLS1) and full cross validation in the range of 1011-1675 nm and 1930-2488 nm. High coefficients of correlation (r) were obtained between the predicted NIR results and those obtained from traditional chemical method. The correlation coefficient of calibration model and prediction model was 0.99 and 0.97, respectively. The standard error of calibration (SEC) and standard error of prediction (SEP) was 0.36% and 0.59%, respectively. It was found that the lignin content in bamboo could be determined rapidly with reasonable accuracy by the NIR method.

Near infrared spectroscopy is widely used as a quantitative method, and the main multivariate techniques consist of regression methods used to build prediction models, however, the accuracy of analysis results will be affected by many factors. In the present paper, the influence of different sample roughness on the mathematical model of NIR quantitative analysis of wood density was studied. The result of experiments showed that if the roughness of predicted samples was consistent with that of calibrated samples, the result was good, otherwise the error would be much higher. The roughness-mixed model was more flexible and adaptable to different sample roughness. The prediction ability of the roughness-mixed model was much better than that of the single-roughness model.

The contents of holocellulose and lignin of wood are important determinants of the pulping quality of wood. The determination of holocellulose and lignin contents using traditional chemical methods is a costly and time-consuming process. Near infrared reflectance (NIR) analysis offers a fast, nondestructive testing and low cost alternative for prediction of wood quality. In the present article, the total amounts of holocellulose and lignin contents of 48 samples were analyzed according to standard wet-chemical method. All samples were milled using a Standard Wiley knife mill with a 2 mm screen. The 2 mm material was sieved with a 40-60 mesh sieve. Then, near infrared (NIR) spectra were collected in diffuse reflectance from samples of meal contained in a spinning cup by an analytical spectral devices (ASD) Lab Spec at wavelengths between 350 nm and 2 500 nm. The raw spectra were pretreated by the second derivative and smoothing, then the NIR model was built using partial least-squares statistical analysis and full cross validation. The coefficients of correlation (r) of calibration and validation for holocellulose were 0. 96 and 0.93, respectively; the standard error of calibration (SEC) and the standard error of prediction (SEP) were 0.39 and 0.50, respectively. For lignin, the values for r of calibration and validation were 0.99 and 0.90, while the SEC and SEP were 0.10 and 0.28, respectively. It was concluded that NIR analysis is a reliable, fast and nondestructive testing predictor of holocellulose and lignin content of wood in Chinese fir.

Rapid prediction of annual ring density of Paulownia elongate standing trees using near infrared spectroscopy was studied. It was non-destructive to collect the samples for trees, that is, the wood cores 5 mm in diameter were unthreaded at the breast height of standing trees instead of fallen trees. Then the spectra data were collected by autoscan method of NIR. The annual ring density was determined by mercury immersion. And the models were made and analyzed by the partial least square (PLS) and full cross validation in the 350-2 500 nm wavelength range. The results showed that high coefficients were obtained between the annual ring and the NIR fitted data. The correlation coefficient of prediction model was 0.88 and 0.91 in the middle diameter and bigger diameter, respectively. Moreover, high coefficients of correlation were also obtained between annual ring density laboratory-determined and the NIR fitted data in the middle diameter of Paulownia elongate standing trees, the correlation coefficient of calibration model and prediction model were 0.90 and 0.83, and the standard errors of calibration (SEC) and standard errors of prediction(SEP) were 0.012 and 0.016, respectively. The method can simply, rapidly and non-destructively estimate the annual ring density of the Paulownia elongate standing trees close to the cutting age.

Wood, as a biomass materials, tends to be attacked by microorganisms, and its structure could be rapidly destroyed by biological decay. Therefore, it's significant to rapidly and accurately detect or identify biological decay in wood. Recently, extensive research has demonstrated that near infrared spectroscopy (NIR) and soft independent modeling of class analogy (SIMCA) can be used to discriminate or detect a wide variety of food, medicine and agricultural products. The use of NIR coupled with principal component analysis (PCA) and SIMCA pattern recognition to detect wood biological decay was investigated in the present paper. The results showed that NIR spectroscopy coupled with SIMCA pattern recognition could be used to rapidly detect the biological decay in wood. The discrimination accuracy by the SIMCA model based on the training set for the non-decay, white-rot and brown-rot decay samples were 100%, 82. 5% and 100%, respectively; and that for the samples for the test set were 100%, 85% and 100%, respectively. However, some white-rot decay samples were mis-discriminated as brown-rot decay, for which the main reasons might be that the training set does not have enough typical samples, and there's a slight difference between white-rot and brown-rot decay during the early stage of decay.

The crystallinity of wood has an important effect on the physical, mechanical and chemical properties of cellulose fibers. The aims of this study were to investigate the ability of near infrared spectroscopy (NIR) to predict the crystallinity of wood cellulose and the effect of spectral pretreatment on the prediction of crystallinity in wood cellulose using near infrared spectroscopy (NIR). Near infrared diffuse reflectance spectra were collected from wood powder with a fiber-optical probe and the crystallinity of wood was determined by X-ray diffractometer (XRD) in this experiment. The results showed that near infrared spectroscopy coupled with partial least square (PLS) regression could be correlated with the crystallinity of plantation wood, and the ability of NIR prediction based on original spectra was better than that based on the first derivative or second derivative treated spectra. There was a significant correlation between NIR spectra and XRD determined crystallinity with a correlationcoefficient of 0.950 and a low RMSEP. Near infrared spectroscopy coupled with multivariate data anlaysis has proven to be an accurate and fast method for rapid prediction of wood crystallinity.

The effect of stand density (1000 stems/ha, 500 stems/ha and 250 stems/ha) on tree growth and wood quality characteristics was studied in a 27-year-old plantation species of Populus xiaohei in China. Results indicated that stand density had significant effects on tree radial growth and crown size, and the lowest stand density produced trees with the largest stem taper. In terms of wood quality characteristics, there was no significant effect of stand density on either wood basic density or fiber length. However, significant differences were found between different stand densities for wood mechanical properties. A positive relationship between modulus of elasticity, compression strength and stand density was observed, while the highest modulus of rupture was recorded at a moderate density of 500 stems/ha. Stand density was responsible for highly significant effects on both juvenile wood and wet heartwood basal areas in individual trees, and there was an obvious tendency towards increasing juvenile wood and wet heartwood basal areas with decreasing stand density. In addition, the relationships between wood quality characteristics and tree and stand characteristics were also examined. Some wood quality characteristics, namely mechanical properties and juvenile wood and wet heartwood basal areas, were quantified successfully in relation to selected tree characteristics using a regression approach with various degrees of goodness of fit. Based on comprehensive consideration of various factors, such as wood quality, tree growth, and establishment cost, results from this study suggest that a density of 500 stems/ha is optimum for wood production.

In the present paper, near infrared (NIR) spectroscopy and X-ray diffractometry were used to rapidly predict the microfibril angle (MFA). MFA is one of the most important factors affecting wood properties. Wood resource utilization and tree improvement programs require cost-effective methods for the rapid analysis of thousands of samples. In the experiment, the average MFA of each sample were rapidly measured by X-ray scanning diffractometry. Then, the PLS model was built between NIR data and MFA by the X-ray measured. As a result, a very strong linear relationship has been found between NIR spectra fitted and X-ray measured, and the coefficients (r2) of calibration and prediction models were 0.867 and 0.816 respectively.

In the present report, the use of calibrated near infrared (NIR) spectroscopy for rapid prediction of solid wood density is described. NIR spectra were obtained from the three sections (cross, radial and tangential section) of each Chinese fir sample. The authors found that the spectra of the three sections are different and the correlation coefficients between the laboratory-determined density and the NIR-fitted data are different, too. The prediction results showed that the model based on NIR spectra taken from the cross section is the best, and the correlation coefficients are 0.94 (cross), 0.85 (radial) and 0.81 (tangential), respectively. Using the cross model to predict the density of unknown wood samples, we can see: r2 is 0.977 and the standard deviation (STDEV) is only 0.006.

Ketogulonicigenium vulgare Y25 is used in the production of vitamin C, which is responsible for the conversion reaction of l-sorbose to l-ketogulonic acid in mixed culture fermentation with Bacillus species 8. The entire genome of Ketogulonicigenium vulgare Y25 was sequenced to elucidate the metabolic pathway of sorbose and to obtained detailed insights into the growth potential of the organism. The complete genome sequence of Ketogulonicigenium vulgare Y25 was determined by the Beijing Genome Institute (Shenjun, China) using Solexa technology. A total of 221 million high-quality base pairs, giving 67.2-fold coverage of the genome, were assembled into 36 contigs using by SOAP software (http://soap.genomics.org.cn) 7. Then, the contigs were joined into 14 scaffolds using paired-end information. Gaps between contigs were closed by custom primer walks or by PCR amplification followed by DNA sequencing. The genome of Ketogulonicigenium vulgare Y25 consists of a circular chromosome and two plasmids. The chromosome is composed of 2,776,084 bp, with a G+C content of 61.72%. One plasmid contains 268,675 bp, with a G+C content of 61.35%, and the other contains 243,645 bp, with a G+C content of 62.63%. Hence, the total size of the genome is 3,288,404 bp and the average G+C content is 61.76%. There are a total of 3,290 putative open reading frames (2,807 [chromosome], 256 [pYP1], and 227 [pYP2]) using Glimmer, giving a coding intensity of 91.05%. A total of 59 tRNA genes for all 20 amino acids but tyrosine and five 16S-23S-5S rRNA operons were identified. Four genes encoding sorbose dehydrogenase were found in the chromosome. All of them were cloned and characterized. The result indicated that every one could transform l-sorbose into 2-keto-gulonic acid and required pyrroloquinoline quinine for the prosthetic groups in vitro (unpublished data). Sequence alignment analysis showed that they hadhigh homology in nucleic acid and amino acid sequences 1, 4, 9, and 10. It is estimated that multiple copies of the sorbose dehydrogenase gene can be attributed to highly efficient conversion of sorbose to 2-keto-gulonic acid. A pqqABCDE cluster of coenzyme PQQ biosynthesis has also been isolated. It shows the same arrangement of pqq genes as that in other species: a small pqqA gene with its own promoter followed by an operon with the other four genes2, 3, 5, 6. In addition, several genes encoding sorbitol dehydrogenase, sorbose reductase, sorbsone dehydrogenase, etc., were annotated in the genome. The Y25 genome sequence and its curated annotation are important assets to better understand the physiology and metabolic potential of Ketogulonicigenium vulgare and will open up new opportunities in the functional genomics of this species.