The transient mass transter processes in the natural drying of wood particle materials were experimental;y studied A new theory tio determme the mass transfer parameters in the Materials was developed in terms of grad...The transient mass transter processes in the natural drying of wood particle materials were experimental;y studied A new theory tio determme the mass transfer parameters in the Materials was developed in terms of gradient transformation method(GTM).By making use of GTM.Thewater vapour diffusion coefficient and the surtaee emission coefficent of wood chip were expermentally determined both in air phase and in solid phase.It Was found that the internal resistance to water vapour diffusion in the air phase of wood partiele aggregates is around ten to the third power as large as that in common air The drag coefficient was given to quantify the effect The phenomenon of undersurface diffusion in wood partiele bed was quantitatively modelled.The dimensionless Fourier snumber and the Biot's number for mass transfer were theoretically derived.The study showed that Biot's number for the problem investigated was the ratio of the characteristie length of wood partiele bed to the penetrating depth of the undersurface.An analytical solution of the nonlinear goveming equation for water transport process in the aggregates of wood chip was obtained by introducing the variable coefficients measured in the study into the governing equation.The comparison between the analytical solution and the observed moisture content of wood chip showed that the deviation was less than ±7%.The thermophysieal properties of wood particle materials are little known at present.The knowledge provided in the paper will be and in the handling.researeh or engineering application of wood chip.wood shavingsete.展开更多
Geopolymers are inorganic adhesive synthesized from industrial waste such as fly ash thus the development of wood geopolymer composite would be a low carbon footprint material.Geopolymers,being a non-formaldehyde adhe...Geopolymers are inorganic adhesive synthesized from industrial waste such as fly ash thus the development of wood geopolymer composite would be a low carbon footprint material.Geopolymers,being a non-formaldehyde adhesive can be used as an alternative binder for wood based composites where environmentally friendly and sustainability of product is important.In this study flyash as precursor is been used in the development of wood geopolymer composite product.Flyash is activated with a combination of sodium hydroxide and sodium silicate solutions at a weight ratio of 1:2.5 for geopolymer formation.The study investigated the properties of wood geopolymer composite made with ratios of wood particle to flyash percentage(23/77),(37/62),(44/55),(50/50)and(57/43).Geopolymer formation was observed by X-ray Diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).Influence of wood particles in wood geopolymer composite were observed by Scanning electron microscope.The study shows that the water absorption and thickness selling properties of all the formulations of wood geopolymer composites are comparable with the medium density particle board and cement-bonded particleboard according to the IS:3087-2005 standard and IS:12406:respectively.Highest mechanical properties and good bond strength was obtained by the composite containing 23%wood particle ratio with 77%percent flyash.However,still improvement in mechanical properties is needed to achieve the mechanical properties comparable to cement bonded particle board.展开更多
The mechanical properties of wood powder/polypropy!ene composites with different wood particle sizes and wood species have been studied. All of the wood particie sizes increased the E-modulus of the composites. Tensil...The mechanical properties of wood powder/polypropy!ene composites with different wood particle sizes and wood species have been studied. All of the wood particie sizes increased the E-modulus of the composites. Tensile tests showed that wood partide sizes had a negative effect on the elongation at break and the tensile strength of the composites has been improved when wood particle sizes were be(ow 150 μm (below 100 mesh). For the impact tests, the wood partide sizes had a negative effect, but the MDF f...展开更多
文摘The transient mass transter processes in the natural drying of wood particle materials were experimental;y studied A new theory tio determme the mass transfer parameters in the Materials was developed in terms of gradient transformation method(GTM).By making use of GTM.Thewater vapour diffusion coefficient and the surtaee emission coefficent of wood chip were expermentally determined both in air phase and in solid phase.It Was found that the internal resistance to water vapour diffusion in the air phase of wood partiele aggregates is around ten to the third power as large as that in common air The drag coefficient was given to quantify the effect The phenomenon of undersurface diffusion in wood partiele bed was quantitatively modelled.The dimensionless Fourier snumber and the Biot's number for mass transfer were theoretically derived.The study showed that Biot's number for the problem investigated was the ratio of the characteristie length of wood partiele bed to the penetrating depth of the undersurface.An analytical solution of the nonlinear goveming equation for water transport process in the aggregates of wood chip was obtained by introducing the variable coefficients measured in the study into the governing equation.The comparison between the analytical solution and the observed moisture content of wood chip showed that the deviation was less than ±7%.The thermophysieal properties of wood particle materials are little known at present.The knowledge provided in the paper will be and in the handling.researeh or engineering application of wood chip.wood shavingsete.
基金We thank Indian plywood Industries research and training Institute,an autonomous body of Ministry of environment forest and climate change funded this research project.I thank my co-authors for helping me in the study,analysis,and interpretation of data and in writing the manuscript should be declared.
文摘Geopolymers are inorganic adhesive synthesized from industrial waste such as fly ash thus the development of wood geopolymer composite would be a low carbon footprint material.Geopolymers,being a non-formaldehyde adhesive can be used as an alternative binder for wood based composites where environmentally friendly and sustainability of product is important.In this study flyash as precursor is been used in the development of wood geopolymer composite product.Flyash is activated with a combination of sodium hydroxide and sodium silicate solutions at a weight ratio of 1:2.5 for geopolymer formation.The study investigated the properties of wood geopolymer composite made with ratios of wood particle to flyash percentage(23/77),(37/62),(44/55),(50/50)and(57/43).Geopolymer formation was observed by X-ray Diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).Influence of wood particles in wood geopolymer composite were observed by Scanning electron microscope.The study shows that the water absorption and thickness selling properties of all the formulations of wood geopolymer composites are comparable with the medium density particle board and cement-bonded particleboard according to the IS:3087-2005 standard and IS:12406:respectively.Highest mechanical properties and good bond strength was obtained by the composite containing 23%wood particle ratio with 77%percent flyash.However,still improvement in mechanical properties is needed to achieve the mechanical properties comparable to cement bonded particle board.
文摘The mechanical properties of wood powder/polypropy!ene composites with different wood particle sizes and wood species have been studied. All of the wood particie sizes increased the E-modulus of the composites. Tensile tests showed that wood partide sizes had a negative effect on the elongation at break and the tensile strength of the composites has been improved when wood particle sizes were be(ow 150 μm (below 100 mesh). For the impact tests, the wood partide sizes had a negative effect, but the MDF f...
