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11.
Toru Ikegami Hideyuki Negishi Dai Kitamoto Keiji Sakaki Tomohiro Imura Masayoshi Okamoto Yasushi Idemoto Nobuyuki Koura Tsuneji Sano Kenji Haraya Hiroshi Yanagishita 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):381-387
In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry 相似文献
12.
水电站泄水道破坏修复工程,是一项风险高、难度大、前景广阔的系统工程。刘家峡水电站泄水道2号孔破坏修复的关键,是采用人工深水软导向浮体闸门封堵孔口,形成门后洞内旱地施工条件;龚嘴水电站10号冲砂底孔破坏修复的关键,增设浮体闸门采用自动潜行式浮体闸门封堵孔口,形成门后洞内旱地施工条件;哈萨克斯坦CHARDARA水电站SYNAS项目泄水底孔修复的关键,采用分次降水安装浮体闸门侧支承的方法,挡住引水发电机组的下游尾水,在泄水道进口检修门和流道出口之间形成门旱地施工。此3项泄水道修复工程在行业内没有先例,难度很大。整体方案具有创新性,并且均已高质量竣工并投入正常运行。 相似文献
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The purpose of this paper is the modelling of the mechanical behaviour of an elastomeric material, through detailed experimental and numerical procedures, specific to large strains. The experimental technique is based on in-plane kinematics measurements using a speckle extensometer, from which the whole two-dimensional field of in-plane displacements is obtained by a digital image processing [Polymer (2002)]. This part of the work concerns the identification of the constitutive equation for a carbon black natural rubber (NR) vulcanizate. We start by quoting some theoretical considerations relative to rubber elasticity and stress-softening effect, which is the counterpart of the filler reinforcement. Then, we describe the experimental procedure and present data for both non-preconditioned and preconditioned samples. Next, the identification of the constitutive law parameters using a minimization algorithm is driven. Finally, we present the validation of the constitutive model, by its implementation into the finite element code SYSTUS and the numerical simulation of the response of a double edge notched tensile (DENT) specimen. 相似文献
16.
The depolymerization of high-temperature-vulcanized (HTV) silicone rubbers containing filler silica and alumina into cyclosiloxane monomers and spontaneous recovery of fillers were studied. First, HTV silicone rubber was treated with different types of solvents in the presence of KOH to find that a triad mixture of diethylamine, methanol and hexane was appropriate not only to dissolve the silicone rubber to a suspension but also to separate fillers completely by filtration. The filtrate was distilled to remove solvent first and then give pure cyclosiloxane monomers in 76–84% yields. Second, the rubbers were treated with other types of triad mixture of solvents and bases, e.g. tetramethylammonium hydroxide, hexane and diethylamine. After filtration, residue was again treated with the amine and hexane to recover clean fillers in 83–93% yields. Cyclosiloxane monomers were also obtained from the combined filtrates in 67–78% yields. 相似文献
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Uma Maheswar Rao S. S. M. S. Abdul Majeed C. Venkataseshaiah R. Sarathi 《Bulletin of Materials Science》2002,25(6):473-475
In the present work, tracking phenomena has been studied with silicone rubber material under the a.c. and d.c. voltages following
IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric
differential thermal analysis (TG-DTA) studies. The tracking time was different for a.c. and d.c. voltages. 相似文献