Progressive fatigue failure behavior of glass/epoxy (±75)2 filament-wound pipes under pure internal pressure

Fatigue failure behaviors of filament-wound composite pipes under pure internal pressure were investigated. The filament-wound pipes are made of E-glass/epoxy and have four layers which have ±75° winding angle. The fatigue tests have been done in accordance with ASTM D-2992, which stipulate 0.42 Hz frequency and R = 0.05 stress ratio. Tests have been performed at different load levels from 30% to 70% of ultimate tangential strength of the pipe, the damage progression such as whitening, leakage and final failure have been observed, and S–N curves of these damages were obtained.     

Cloning, sequence analysis, and characterization of the genes involved in isoprimeverose metabolism in Lactobacillus pentosus

Two genes, xylP and xylQ, from the xylose regulon of Lactobacillus pentosus were cloned and sequenced. Together with the repressor gene of the regulon, xylR, the xylPQ genes form an operon which is inducible by xylose and which is transcribed from a promoter located 145 bp upstream of xylP. A putative xylR binding site (xylO) and a cre-like element, mediating CcpA-dependent catabolite repression, were found in the promoter region. L. pentosus mutants in which both xylP and xylQ (LPE1) or only xylQ (LPE2) was inactivated retained the ability to ferment xylose but were impaired in their ability to ferment isoprimeverose (alpha-D-xylopyranosyl-(1,6)-D-glucopyranose). Disruption of xylQ resulted specifically in the loss of a membrane-associated alpha-xylosidase activity when LPE1 or LPE2 cells were grown on xylose. In the membrane fraction of wild-type bacteria, alpha-xylosidase could catalyze the hydrolysis of isoprimeverose and p-nitrophenyl-alpha-D-xylopyranoside with apparent Km and Vmax values of 0.2 mM and 446 nmol/min/mg of protein, and 1.3 mM and 54 nmol/min/mg of protein, respectively. The enzyme could also hydrolyze the alpha-xylosidic linkage in xyloglucan oligosaccharides, but neither methyl-alpha-D-xylopyranoside nor alpha-glucosides were substrates. Glucose repressed the synthesis of alpha-xylosidase fivefold, and 80% of this repression was released in an L. pentosus delta ccpA mutant. The alpha-xylosidase gene was also expressed in the absence of xylose when xylR was disrupted.     

ITMA 2007: 针织技术的创新和发展趋势

概述了2007年世界纺机展中针织技术的创新及产品发展趋势,重点介绍全球几大著名针织设备生产商的最新产品.     

New solutions for the manufacturing of spacer preforms for thermoplastic textile-reinforced lightweight structures

The novel woven spacer fabrics consist of upper and lower layers which are connected through internal crosslinks. The aim is to weave spacer fabrics with woven crosslinks in a single production step as near net shape sandwich preforms. By this way reproducible and automated manufacturing of sandwich preforms for composites are realized. The paper deals at first with the conception of a new weaving and take-up technology of complete spacer fabrics without subsequent textile assembly processes. Afterwards, the special technology is described, and finally the paper deals with a simulation model for the prediction of dynamic warp thread forces in order to minimize fiber damage during weaving process.     

Analysis of Agricultural Water Allocation and Returns in the Sultanate of Oman

Water is the most important determinant of agricultural production in Oman. Remarkable public and private investments have been drawn into water resources development and into the modernization of the farming techniques in order to strengthen the contribution of agriculture to the national economy. In spite of these technological improvements and significant investments, water allocation remains a major policy issue. This paper discusses current water use and explores alternatives for improved allocation of agricultural water. Available data suggest that physical and economic returns to water are low. Improvement of returns to water resources could come from producing higher quality and higher value crops for domestic and foreign markets using improved irrigation techniques. This trend needs to be enforced by stringent water conservation measures in order to reach a long-term sustainable water use.     

Development of a System for Temperature Profile Characterization of Baths

Liquid baths are the main calibration equipment to directly affect the measurement uncertainty in temperature calibrations. Therefore, the characteristics of baths need to be well investigated and understood. The temperature profile and stability of liquid baths are one of the most important contributions to the calibration uncertainty of platinum resistance thermometers, digital thermometers, liquid-in-glass thermometers, and thermocouples. Commercial baths only present stability and uniformity data in two dimensions in general; however, thermometers and thermocouples are immersed into the body of the bath, so the depth or z-axis is also very important. In this study, a measurement system has been designed using three-stepper motors and a data acquisition system (DAS). The DAS is developed using object-oriented algorithms to form a three-dimensional (3-D) scanning system. The 3-D scanning system is home-made and used in conjunction with a reference platinum thermometer. The temperature profiles and stability of several types of baths: water, oil, and salt were obtained in the temperature range from 30???C to 450???C. Therefore, this contributed toward a more accurate uncertainty budget evaluation.     

Synthesis and Characterization of Carboxylated Luteolin (CL)-Functionalized SPION

In this study, a stable carboxylated luteolin (CL)-functionalized superparamagnetic iron oxide nanoparticle (SPION) as a potential drug carrier for in vitro analysis of L929 (mouse fibroblast), U87 (glioblastoma (brain cancer)), MCF-7 (breast cancer), HeLa (cervix cancer), and A549 (human lung cancer) cell lines has been synthesized. Thermal decomposition and Stöber methods were used to prepare 3-aminopropyl triethoxysilane-capped SPIONs respectively. Carboxylated polyethylene glycol (PEG-COOH), folic acid (FA), and CL were conjugated on the surface via a carboxylic/amine group using the nanoprecipitation method respectively. Internalization of CL-functionalized SPION and the release of luteolin from it has been studied using Prussian blue staining and spectrophotometry respectively. The cytotoxicity of CL-functionalized SPION on cell lines was tested by MTT assay. Internalization of product by HeLa, MCF-7, and U87 was higher than A549 and L929 cells. It was observed that luteolin release increased in an acidic environment (pH 5.4). A newly synthesized SPION-FA-PEG in all concentrations (except 500 μg/mL) did not show notable toxicity against L929, U87, MCF-7, HeLa, and A549. However, the product in all used concentrations decreased cell viability at the 24th and 48th hours. This study confirmed that the product has a potential to be used as an anti-cancer CL-functionalized SPION for targeted drug delivery.