A kind of porous woodceramics was prepared by carbonizing sanding fir wood powder impregnated with phenolic resin (PF) in vacuum. The carbonization process parameters of woodceramics was determined by the investigatio...
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A kind of porous woodceramics was prepared by carbonizing sanding fir wood powder impregnated with phenolic resin (PF) in vacuum. The carbonization process parameters of woodceramics was determined by the investigation of pyrolysis characteristics of wood powder and phenolic resin using differential scanning calorimetry (DSC). The effects of the heating rate and carbonization temperature on dimension shrinkage, weight variation, dimension stability, mechanical properties, electromagnetic shielding property and microstructure of the woodceramics were discussed. The results show that the woodceramics has stability properties when carbonized at 800°C with the heating rate 10°C/min from room temperature to 1201 and 2-5°C/min above 120°C. The results also indicate that the wear mass loss of the woodceramics decreases and the dimension stability increases with heating rate decreases, while compressive strength, bending strength, electromagnetic shielding property and wear mass loss of the woodceramics all increase with the carbonization temperature increases, but the increase of dimension shrinkage is not obvious. According to the results of SEM observation, the woodceramics exhibits graphitization trend when carbonized at 1400°C.
Arabinogalactan (AG) obtained from Larix gmelinii R. waS purified with the method of macroporous resin adsorption. Effects of various parameters on the adsorption, including adsorption time and temperature, the conc...
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Arabinogalactan (AG) obtained from Larix gmelinii R. waS purified with the method of macroporous resin adsorption. Effects of various parameters on the adsorption, including adsorption time and temperature, the concentration and the dosage of raw AG the reused numbers of resin, were investigated. The effect of purification was tested through the removal rate of impurity and the contents of AG and impurity. The optimal condition was determined as follows: adsorbed at 30℃ for 2 h with the concentration of raw AG 〈0.1 g·mL^-1 and its dosage 〈 7 mL, the dose of resin was 3 g and reused for 4 times. On the basis of these, macroporous resin column was used for AG purification. The result showed that the AG yield could reach 68.28% with sugar content of 95.02%. The analysis of IR and UV showed that the effect of macroporous resin characteristics on the purification of AG was significant. The obtained product had the same functional groups with standard sample.
The small-diameter lumbers of Daimyo Oak (Quercus dentata) were dried with consecution-heat method and intermittent-heating methods (intermittent 2h and intermittent 6h) to study the occurred stress of surface layer o...
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The small-diameter lumbers of Daimyo Oak (Quercus dentata) were dried with consecution-heat method and intermittent-heating methods (intermittent 2h and intermittent 6h) to study the occurred stress of surface layer of them during conventional drying process. The results show that the total stress was elongate stress at first, the elongate stress became large and got to the most, then became small and changed into compress stress, the compress stress became large and got to the most, and then became small, with the fall of moisture content of the lumber;the residual stress became large, and became small again after got to the most;the change of stress of surface layer with three kinds of heating methods were in a similar way. However, the stress with intermittent-heating was smaller than that with consecution-heat during either prophase drying or metaphase drying, and the stress was least with intermittent 6h. At the same moisture content level, the stress of surface layer of tangential lumber was larger than that of radial lumber.
The authors introduced four MATLAB image-processing programs for orientated strand board (OSB) research. These programs have been used to detect OSB panel voids, to characterize voids within the simulated mat, and to ...
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The authors introduced four MATLAB image-processing programs for orientated strand board (OSB) research. These programs have been used to detect OSB panel voids, to characterize voids within the simulated mat, and to transform the distorted images from the X-ray scanning system and Infrared system. The successful running of these programs showed that the primary programming codes were compact and efficient, and that image processing programs can be used for different applications in OSB research, including panel and mat voids measurements as well as image transformation. By means of simple modifications it is possible for the programs to fulfill more complex image processing procedures than the examples specified in this paper. These programs and their program design principles can be directly utilized as a reference in research and teaching, especially for image analysis of composite panels and/or mats.
MA-SEBS as compatibilizer and impact modifier was incorporated into Polypropylene/Wood Fiber (PP/WF) to enhance interface adhesion and impact strength of the composite. The effect of MA-SEBS content on the impact fr...
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MA-SEBS as compatibilizer and impact modifier was incorporated into Polypropylene/Wood Fiber (PP/WF) to enhance interface adhesion and impact strength of the composite. The effect of MA-SEBS content on the impact fracture behavior of PP/WF composites was studied. The impact properties of composites with 8% MA-SEBS reached the maximum value. And further increasing of MA-SEBS content to 10% did not improve the fracture toughness, but improved the stiffness of composites by DMA analysis. This was attributed to the improved PP/WF adhesion. As the MA-SEBS content is more than 8%, the molecule interaction of PP and WF was expected to much stronger than lower MA-SEBS. Scanning electron microscopy (SEM) was performed to analyze the impact fracture surface and showed a stronger affinity for the wood surfaces.
The voids formation in bio-based composite mat was researched by using computer simulation technology. Different processing variables were investigated to find their relationship to the void volume ratio in the mat, w...
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The voids formation in bio-based composite mat was researched by using computer simulation technology. Different processing variables were investigated to find their relationship to the void volume ratio in the mat, which included material geometry, and nominal board density. The simulated and experimental data were then compared. The results indicate the simulated and experimental data have the same changing trends with the processing conditions. Moreover, to explain the effect of the void on heat and mass transfer, the temperature and air pressure of the mat center were measured during hot pressing. The results from experiments and analyses are also able to indicate that this model and simulation could be used to research the characteristics of the void in bio-based composite mat and heat and mass transfer during hot pressing.
Since the complex operation environment in wood drying kiln, the precision of lumber moisture content (LMC) is affected greatly with the ambient parameters which have closed multi-couple and correlated relation with t...
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Since the complex operation environment in wood drying kiln, the precision of lumber moisture content (LMC) is affected greatly with the ambient parameters which have closed multi-couple and correlated relation with them. based on above reasons background, a comparison study on self-calibration level fusion algorithm based Bayes estimation theory for wood drying-kiln industry process is presented in this paper. Starting with analyzing the existing problems of LMC measured by individual sensor, we then put forward the architecture of multi-sensor data fusion for LMC measuring system. The performance of self-calibration level is detailed discussed. The technique of the determination of confidence distance and optimal fusion set, the total probability maximum algorithm, the Bayes estimation algorithm, and arithmetic averaging method are investigated respectively. Comparison the simulation results, a self-calibration fusion algorithm based Bayes estimation theory is determined.
The chemical components of dichloromethane extractives for Sawara Falsecypress heartwood were analyzed with GC/MS except for basic chemical composition analysis for heartwood with Chinese standard method. 14 kinds of ...
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The chemical components of dichloromethane extractives for Sawara Falsecypress heartwood were analyzed with GC/MS except for basic chemical composition analysis for heartwood with Chinese standard method. 14 kinds of compounds were idenfifjed according to the computer compounds library data. The major compounds in dichloromethane extractives comprised of terpene and naphthalene derivafives. The experiments of antifungal effects of the dichloromethane extractive on Aspergillus niger were also carded out. The result showed that the dichloromethane extractive from Sawara Falsecypress has no or weak antifungal capability.
The discoloration of Scot pine (Pinus sylvestris var. Mongolica) veneers caused by resin-eliminated treatment and the reversion of the color were studied. The result showed that the color of the veneers changed from...
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The discoloration of Scot pine (Pinus sylvestris var. Mongolica) veneers caused by resin-eliminated treatment and the reversion of the color were studied. The result showed that the color of the veneers changed from buff to yellowish brown after the treatment of resin elimination and the discoloration of heartwood was more severe than that of sapwood; the degree of discoloration was significantly positively correlated with the medicament strength, temperature and resin-eliminated duration. The variance analysis showed the effects of those three factors on the discoloration were significant. With hydrogen peroxide (H2O2) as color reversion medicament and inorganic compound as medium of the reaction, the reversion of the color of heartwood was more inaccessible than that of sapwood; the degree of the color’s reversion was positively correlated with the H2O2 strength, temperature and treating time; the H2O2 concentration has significant effects on the discoloration. In order to reduce discoloration of Scot pine veneers, medicament of resin-eliminated used have to be at some low concentration, and the optimal concentration of H2O2 is 0.35% during the process of color’s reversion.
Intermittent heating for drying of small diameter Larch lumbers is investigated experimentally. The lumbers were dried using an experimental drying schedule. Moisture content (MC) of the lumber was continuously record...
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Intermittent heating for drying of small diameter Larch lumbers is investigated experimentally. The lumbers were dried using an experimental drying schedule. Moisture content (MC) of the lumber was continuously recorded and final drying defects were examined. The drying curves showed that the drying rate was a constant in the early stage of intermittent heating drying and decreased evidently when the MC was about 18% (intermittent 2h) and 20% (intermittent 6h). The drying quality reached the second (intermittent 2h) and first grade (intermittent 6h) of the Chinese National Standard. The visual drying defects, especially the check extent along grains were reduced with intermittent heating. When the intermittent time increased, the effect was more obvious.
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