Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic ...Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.展开更多
A novel method based on plastic processing and equipment for preparing ultra-fine metal fibers and particles is reported.With this new method,metal fibers and particles can both be produced on the same equipment and t...A novel method based on plastic processing and equipment for preparing ultra-fine metal fibers and particles is reported.With this new method,metal fibers and particles can both be produced on the same equipment and the surfaces of the fibers and particles can be protected from oxidation by the polymers or solvents during the preparation process.Metal-alloy powders with lower melt point were filled into polymer by an extruder,followed by a die-drawing process at a temperature lower than the melt temperature of the metal alloy.Metal fibers or particles were obtained after the polymer matrix was washed away.Metal alloy fibers can be obtained when a polymer that strongly interacts with metal alloy,such as a special polyvinyl alcohol with a low alcoholysis degree,is used as the polymer matrix.Metal-alloy particles can be obtained when a polymer with weak interaction with metal alloy,such as polyethylene(PE),is used as the polymer matrix.Based on the principle of this new method,it is possible to produce finer or even nano-sized metal fibers and particles with higher melting points.展开更多
基金Supported by National Science Foundation of USA(CMMI-0970112)
文摘Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.
文摘A novel method based on plastic processing and equipment for preparing ultra-fine metal fibers and particles is reported.With this new method,metal fibers and particles can both be produced on the same equipment and the surfaces of the fibers and particles can be protected from oxidation by the polymers or solvents during the preparation process.Metal-alloy powders with lower melt point were filled into polymer by an extruder,followed by a die-drawing process at a temperature lower than the melt temperature of the metal alloy.Metal fibers or particles were obtained after the polymer matrix was washed away.Metal alloy fibers can be obtained when a polymer that strongly interacts with metal alloy,such as a special polyvinyl alcohol with a low alcoholysis degree,is used as the polymer matrix.Metal-alloy particles can be obtained when a polymer with weak interaction with metal alloy,such as polyethylene(PE),is used as the polymer matrix.Based on the principle of this new method,it is possible to produce finer or even nano-sized metal fibers and particles with higher melting points.
