Search

Abstract: The influence of Y on microstructure and mechanical properties of as-cast Mg–5Li–3Al–2Zn alloy was investigated. The results show that the phase compositions of Mg–5Li–3Al–2Zn consist of α-Mg and AlLi phases. Adding Y to the alloy results in the formation of Al2Y compound and facilitates grain refinement. The addition of 0.8wt.% Y produces the smallest grain size. The tensile tests performed at room temperature show that the additions of Y can improve the mechanical properties of the alloy; the tensile strength and ductility reach peak values when the Y additions are 0.8wt.% and 1.2wt.%, respectively. The mechanisms of improvement are related to grain refinement and compound strengthening effects. [Copyright &y& Elsevier]

Abstract: The aim of this study is to investigate the influence of extractives on the yield and composition of oil obtained from biomass samples (Artemisia ordosica, corn stalk and wheat straw). Direct deoxy-liquefaction experiments of original and extracted biomass were performed at certain temperature in a stainless steel tubular reactor. Benzene–alcohol solvent extraction had significant effect on the product distribution of biomass, especially on the yield and composition of the product oils. The oil yield of original biomass and alkane content in the oil were in the range of 5.44–9.27% and 8.23–23.64%, while decreased to 3.83–4.45% and 1.07–6.03% for the extracted biomass. This study concludes that most of alkanes in the oil mainly derive from the decomposition of triglyceride and hydrocarbon existed in the extractives of biomass. The results might be helpful to study the origin of alkanes and benzene derivatives in the oil obtained from biomass via direct deoxy-liquefaction. [Copyright &y& Elsevier]

Abstract: Co-deoxy-liquefaction of biomass and vegetable oil was investigated under the conditions of different temperatures (350–500°C) and residence time as well as catalyst using HZSM-5. Results suggested low temperature was favorable for the formation of diesel-like products, while high temperature caused more gasoline-like products. By the addition of HZSM-5, at 450°C alkanes content of the obtained oil with low oxygen content of 2.28%, reached a maximum of 56.27%, resulting in the highest HHV of 43.8MJkg−1. High temperature favored cracking activity of HZSM-5 which reduced the char formation and contributed to the removal of carbonyl. Compared to temperature, the effect of residence time on products was relatively less; experiments indicated the optimum residence time was 15min at which obtained oil with the highest yield of 17.78%, had better properties. Preliminary analysis of mechanisms showed biomass provided hydrogen for vegetable oil, facilitating hydrogenation of Cf vegetable oil. [ABSTRACT FROM AUTHOR]

Abstract: Since the post-casting treatments influence the water entrapped in polymeric matrix and consequently its proton conductivity, an evaluation of annealing at 200°C and acid treatments was conducted on previously developed composite s-PEEK (1.55mequiv.g−1) membranes, containing a commercial aminopropyl-functionalised silica. DSC, WAXS, SEM–EDX and laser microscope measurements carried out on membranes swollen at different temperatures highlighted different membrane properties depending on post-casting treatments. It was found that composite membranes have different structural and morphological characteristics than pristine polymer membranes. The silica distribution was modified when different treatments are used. The state of water changed when silica was inserted into the membranes. Actually, contrary to the pristine membranes the presence of freezable water was revealed at temperature lower than 80°C. The proton conductivity was also affected by the presence and the amount of water trapped into the membranes and was particularly influenced by the post-casting treatments. The silica introduction reduced the swelling effect and improved the robustness of the membranes even if a higher water content in the freezable state was observed. Acid treatment leads to significant improvement in membrane properties, but the present work shows that annealing before acid treatment can affect the membrane morphology more strongly than other treatments resulting in a much better fuel cell performance. [Copyright &y& Elsevier]