Frictional behaviour of wood-Plastic composites against cemented carbide during sliding contact

This study provides guidelines for the industrial machining of wood-plastic composites, focusing on their behaviour under friction, specifically when friction is caused by sliding contact with cemented carbide. Using the response surface method (RSM) to explore the correlation between the friction coefficient and the wood-plastic composite type, loading force, and reciprocating frequency, a series of frictional tests were performed. The significant contributions of each factor and their two-factor interactions were determined by analysis of variance (ANOVA), with a significance level of 5%, while trends in the variation of the friction coefficient were investigated by using a response surface methodology. The wood-plastic composite types had the greatest impact on the friction coefficient, followed by loading force and reciprocating frequency. A mathematical model (CoF = −0.10 + 0.09ω−0.02f+0.01Fn−0.01ωf+2.38×10−3ωFn−2.00×10−4Fnf+0.11ω2+2.96f2−1.04×10−4Fn2) was developed to accurately predict changes in the friction coefficient during machining of such composites. According to the results of the optimisation, wood-plastic composite with polypropylene should be machined with high-speed cutting, whereas those with polyethylene and polyvinyl chloride are recommended for low-speed machining, so as to ensure the lowest friction coefficient.Funder: National Natural Science Foundation of China (31971594); Natural Science Foundation of the Jiangsu Higher Education Institutions of China (21KJB220009); the SelfMade Experimental and Teaching Instruments of Nanjing Forestry University in 2021 (nlzzyq202101); Technology Innovation Alliance of Wood/Bamboo Industry (TIAWBI2021-08); International Cooperation Joint Laboratory for Production, Education, Research and Application of Ecological Health Care on Home Furnishing</p

Collagen Extracted from Bigeye Tuna (<i>Thunnus obesus</i>) Skin by Isoelectric Precipitation: Physicochemical Properties, Proliferation, and Migration Activities

Collagen was extracted from bigeye tuna (Thunnus obesus) skins by salting-out (PSC-SO) and isoelectric precipitation (PSC-IP) methods. The yield of the PSC-IP product was approximately 17.17% (dry weight), which was greater than the yield obtained from PSC-SO (14.14% dry weight). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that collagen from bigeye tuna skin belongs to collagen type I. Inductively coupled plasma mass spectrometry results indicate that the heavy metal abundance in PSC-IP was lower than the maximum acceptable amounts according to Chinese regulatory standards. In addition, results from a methylthiazolyldiphenyl-tetrazolium bromide assay and an in vitro scratch assay demonstrated that PSC-IP could promote the proliferation and migration of NIH-3T3 fibroblasts. Overall, results suggest PSC-IP could be used to rapidly extract collagen from marine by-products instead of traditional salting-out methods. Collagen from bigeye tuna skin may also have strong potential for cosmetic and biomedical applications

Dual-Layer Nanostructured Flexible Thin-Film Amorphous Silicon Solar Cells with Enhanced Light Harvesting and Photoelectric Conversion Efficiency

Three-dimensional (3-D) structures have triggered tremendous interest for thin-film solar cells since they can dramatically reduce the material usage and incident light reflection. However, the high aspect ratio feature of some 3-D structures leads to deterioration of internal electric field and carrier collection capability, which reduces device power conversion efficiency (PCE). Here, we report high performance flexible thin-film amorphous silicon solar cells with a unique and effective light trapping scheme. In this device structure, a polymer nanopillar membrane is attached on top of a device, which benefits broadband and omnidirectional performances, and a 3-D nanostructure with shallow dent arrays underneath serves as a back reflector on flexible titanium (Ti) foil resulting in an increased optical path length by exciting hybrid optical modes. The efficient light management results in 42.7% and 41.7% remarkable improvements of short-circuit current density and overall efficiency, respectively. Meanwhile, an excellent flexibility has been achieved as PCE remains 97.6% of the initial efficiency even after 10 000 bending cycles. This unique device structure can also be duplicated for other flexible photovoltaic devices based on different active materials such as CdTe, Cu­(In,Ga)­Se₂ (CIGS), organohalide lead perovskites, and so forth