通讯机构：
[Liqiang Zhang] A;[Hui Li] S;State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China
摘要：
The 34-day anoxic storage of Pinus massoniana sawdust (PS) in a sealed constant temperature and humidity chambers was carried out to simulate the limited-oxygen storage process inside piles at industrial scale. The effects of anoxic storage on feedstock's properties and pelletization process were investigated with respect to elemental composition, dry matter loss, thermogravimetric characteristics, energy consumption, pellets' density, and microbial communities, etc. After anoxic storage, the microbial community of PS samples was altered, such as the fungi content (Clonostachys, Strelitziana, and Orbilia, etc.), resulting the elemental composition of PS was altered. Thus, the cellulose and ash content of the stored PS were increased, while the hemicellulose, volatile, and fixed carbon were decreased. The energy consumption was increased 7.85-21.98% with the increase in anoxic storage temperature and with the additive of fresh soil collected from PS field in storage process. The single pellet density was altered slightly. Meanwhile, the moisture uptake of PS pellets was decreased. After anoxic storage, the combustion behavior of the stored PS became more stable. The results can be applied directly to guide the development of commercial PS storage and pelletization process currently under development in Asia, Europe and North America.
摘要：
Ultra-high strain rate impact tests were conducted by Split-Hopkinson pressure bar to investigate the microstructure evolution and impact deformation mechanism of a solution treated casting AM80 Mg alloy at 25, 150 and 250 degrees C with a strain rate of 5000 s -1. The microcrack and dynamic recrystallization (DRX) preferentially nucleate at grain boundary (GB) and twin boundary (TB), especially at the intersections between GBs and TBs, and then propagate along twin direction. In contrast, the adiabatic shear bands preferentially occur at high-density twined regions. At 25 degrees C, the dominated deformation mechanisms are basal slip and twinning. As deformation temperature increases to 150 and 250 degrees C, the deformation gradually shifts to be dominated by a coordinated mechanism among non-basal slip, twinning and DRX. The flow stress behavior and deformation mechanism indicate that the degree of decrease in flow stress with temperature is associated with the change of deformation mode.(c) 2021 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Peer review under responsibility of Chongqing University
作者机构：
[陈斐洋; 郭鹏程; 胡泽豪; 马洪浩; 张立强] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha;410004, China;State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University, Changsha;410082, China;[陈斐洋; 胡泽豪; 马洪浩; 张立强] 410004, China
摘要：
A Hadfield steel has been investigated to clarify the serrated flow and to explore the failure behavior at room temperature. The tensile experiments were performed under extensometer-measured strain control, rather than under conventional cross-head displacement control, at strain rates ranging from 6 x 10(-3) s(-1) to 6 x 10(-6) s(-1). Three types of serrations, including type A, B and C ones, are observed. The occurrence of different types of serrations depends on both strain rate and strain level. The type C serration is identified in Hadfield steels at room temperature for the first time. At high strain rates, there is substantially higher serration density and reduction in stress compared with that observed at low strain rates. Furthermore, two different initiation modes of deformation bands are revealed. The fracture crack nucleates at a position with dense twins, and propagates primarily in the direction perpendicular to the tensile axis and deflects frequently due to the interaction with the boundary of grains and twins. (C) 2019 The Authors. Published by Elsevier B.V.
摘要：
Warm compaction technology is an eco-friendly method to improve the added value of poplar. In this work, the wood powder was compacted in the mold between 120 degrees C to 200 degrees C, at 80 MPa for 30 min. The color change, chemical properties, and mechanical properties were evaluated. The color of the formed compaction darkened uniformly. The CIE lightness color coordinate (L*) and chroma coordinates a* and b* decreased with the increase of forming temperature. Fourier infrared spectral analysis showed degradation of carbohydrates, along with the formation of a new chemical structure of darker color. Mechanical properties including modulus of rupture (MOR) and modulus of elasticity (MOE) of compacted wood increased initially and then decreased. These results provide a reference for the surface color control of thermally forming materials.
期刊：
IOP Conference Series: Materials Science and Engineering,2019年562(1) ISSN：1757-8981
通讯作者：
Zhang, L.Q.(21384881@qq.com)
作者机构：
[Zhang, L.Q.; Yan, Y.L.; Xie, Y.Y.] Mechanical and Electrical Engineering Institute, Central South University of Forestry and Technology, Changsha, Hunan, 410000, China;[Tan, C.Z.] Changan Oushang Automotive Research Institute, Chongqing, 400023, China;[Qiu, S.W.] State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University, Changsha, Hunan, 410082, China
