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Peracetic acid (PAA) is one of the most commonly used bleaching agents in the textile industry. The structural changes of jute fibers after PAA treatment are important in creating industrial applications. An investigation was carried out to determine the structural changes resulting from the removal of noncellulosic materials from jute fibers by PAA. The surface features of jute fiber were studied using a scanning electron microscope. PAA was effective in separateingindividual cellulose fibers from raw jute. However, fibers were damaged when the treatment time reached 80 minutes, PAA concentration was 10 wt. % and the pH was in the 4~5 range. The delignification by PAA treatment was confirmed by Fourier transform infrared spectroscopy. CP/MAS 13 C-NMR spectroscopy showed that the PAA did cause some macromolecular structure changes in the cellulose fibers. X-ray diffraction technique demonstrated that there were four stages of crystallinity change, due to the removal of noncellulosic materials. These four stages include attack at the surfaces of cellulose crystallites, the dissolution of amorphous zones, attack of the inner cellulose crystallite and oxygen interference, respectively.

Abstract. Jute is the second most important fiber in the world, which is easy to grow on all types of soil from clay to sandy loam. The popularity of jute is attributable to its abundant and cheapness, and jute fiber is mainly used in the manufacture of coarse fabrics like bags, hessian, sacking, canvas and twines. Jute is rich in cellulose, which could be served as promising candidates for nano materials production. Nano cellulose features concerned its high strength and stiffness, renewability, low density, biodegradability, low thermal expansion coefficient and high aspect ratio. Fields of use of nanocellulose include reinforcement of nanocomposite materials, thickening agents, tissue engineering scaffolds, dry-strength additive for paper, filtration media, adsorbents, etc. This review summarizes progress in nanocellulose preparation and also discusses recent developments in nanocomposite fabrication based on jute fibers.

Abstract. The dynamic load-sharing characteristics of aircraft face gear dual-power split transmission system (FGDPSTS) are taken as the research object. Considering the factors of time-varying meshing stiffness, comprehensive error, backlash, support clearance, spline clearance, torsional stiffness, and support stiffness, the dynamic load-sharing model was constructed based on the lumped-parameter method. The loaded tooth contact analysis (LTCA) simulation method was used to calculate the time-varying meshing stiffness. The dynamic load-sharing coefficient (DLSC) is obtained by using Runge–Kutta method. The influences of errors, backlash, support clearance, spline clearance, torsional stiffness and support stiffness on DLSC were analyzed, and the biggest factors affecting dynamic load-sharing performance were found out. The results show that the influence of the backlash of the two-stage herringbone gear pair on the DLSC is more sensitive. The influence of support clearance on the DLSC is less. The load-sharing coefficient increases with the increase of the installation error and eccentricity error, and the influence of the error of the two-stage gears on the system load-sharing performance is the most sensitive. The torsional stiffness has little effect on the load-sharing coefficient of one stage but has great effect on the two-stage load-sharing coefficient. The influence of support stiffness on the DLSC of two-stage is stronger. It provided a theoretical basis for the dynamic stability optimization design of the system.

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