Modeling the effect of elastane linear density,fabric thread density,and weave float on the stretch,recovery, and compression properties of bi-stretch woven fabrics for compression garments

The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch, and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the regression equations showed good prediction ability of the developed statistical models. The findings of the study may be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery, and compression properties.     

Fabrication of innovative charkha for pashmina spinning and its impact assessment

Pashmina, a finest natural animal fiber is utilized for preparation of world famous Kashmiri pashmina shawls by traditional practices. Hand spinning is one of the important processing step, wherein fibers are converted into a fine yarn on a traditional spinning wheel (yander). The task is usually carried out by women folk. It is a laborious process resulting in a lot of physical stress affecting the efficiency of artisans. An innovative charkha has been fabricated to reduce the physical stress and its effect on the spinning efficiency and remuneration of artisans over traditional one was evaluated. The study revealed that innovative charkha was efficient in terms of time consumed for spinning by 73.50% over traditional one besides decreasing physical drudgery. In terms of income, there was an increase of 146% over traditional one for same period of time without deteriorating the quality of yarn.     

Magnesium alkyl reduced titanium (IV) chloride based polymerization catalysts: materials rich in magnesium chloride

Reduction of TiCl₄ with organomagnesiums either in the presence of preformed MgCl₂, or concurrently with the formation of MgCl₂ from chlorocarbons, yields materials which are active catalysts for the polymerization of propene and ethene. Transformation of these materials to a violet allotrope by heating with TiCl₄ gives materials much more active for propene polymerization, albeit stereoregulation is still not good. interestingly, these transformed materials show little advantage for ethene polymerization except at high temperatures. Use of a Lewis base does not give high stereoregulation with propene; although some advantage is gained activity is greatly diminished by this.     

Performance Evaluation of a Commercial Polyurethane Coating in Marine Environment

A material evaluation study has been carried out to determine corrosion behavior of a commercial polyurethane coating system (Souplethane 5) in the marine environment. The coating system is solvent free, two-component polyurethane protective coating. The performance of the coating on steel and rebar concrete was evaluated by conducting different types of tests which include atmospheric exposure, immersion in 5% sodium chloride solution, exposure to splash zone in seawater, salt fog, sabkha soil burial, and electrochemical tests, which include potentiodynamic polarization and AC impedance measurements. Uncoated, coated, and coated scribed specimens were used in each study. In general, the coating showed good corrosion resistance in marine environment. However, the coated samples, when subjected to break under applied compressive load, showed partial or complete detachment from the substrate, e.g., steel and rebar concrete. This appears to be the major drawback of the coating while applying on steel and concrete structures.     

Implementation and experimental studies of an adaptive self-optimizing power system stabilizer

This paper describes the implementation and experimental studies of an adaptive self-optimizing pole shifting power system stabilizer. Using an Intel iSBC386/21 single-board computer, the adaptive power system stabilizer has been tested on a physical model of a single-machine infinite-bus power system. Under different operating conditions and disturbances, the behavior of the proposed adaptive stabilizer was investigated. Comparison has also been made to a digital-type conventional fixed-parameter power system stabilizer. Results of the experimental studies show that the proposed adaptive stabilizer outperforms the conventional stabilizer.     

Fatigue delamination growth under cyclic compression in glass/epoxy composite beam/plates

Results are reported on the fatigue growth of internal delaminations in glass/epoxy composite beam/plates subjected to constant amplitude cyclic compression. Because of compressive loading, these structures undergo repeated buckling/unloading of the delaminated layer with a resulting reduction of the interlayer resistance. A noteworthy feature of the problem is that the state of stress near the delamination tip is of mixed mode (I and II). The present combined experimental/analytical investigation for the glass/epoxy composites complements our earlier studies on delamination growth under cyclic compression in unidirectional graphite/epoxy specimens. Several configurations are studied with the delamination located at different depths (through the thickness) and with different applied maximum compressive displacements. The experimental data are correlated with the predictions from a combined delamination buckling/postbuckling and fracture mechanics model. A mode-dependent fatigue delamination growth law is used together with an initial postbuckling solution for the deformation pattern of the delaminated layer and the substrate, which does not impose any restrictive assumptions on the delamination thickness and plate length. The experimental data seem to be adequately correlated with the theory and the fatigue delamination growth is found again to be strongly affected by the relative location of the delamination through the plate thickness. Finally, a comparison of the cyclic growth rate in glass/epoxy specimens with the corresponding one in graphite/epoxy specimens of the same geometry and applied loading shows that the delamination would grow much faster in the graphite/epoxy specimens.     

Dependence of thermal sensitivity of LPFG on waveguide and material parameters

This article demonstrates the effect of waveguide and material parameters on thermal sensitivity trends adopted by different cladding modes based on long-period fiber grating. Three-layer fiber geometry-based mathematical model has been implemented to estimate cladding modes. It is observed that for a cladding mode, the sign and magnitude of thermal sensitivity slope depend upon the designed grating period closer to period at dispersion turn around point. The \(\hbox {LP}_{10}\) and \(\hbox {LP}_{11}\) cladding modes have shown blueshift and maximum thermal sensitivity above all other modes at designed grating periods of 225 and \(195\,\upmu \hbox {m}\), respectively. The material parameter of fiber (thermo-optic coefficient) has also resulted in increment in sensitivity with the increase in difference amid its values for core and cladding region.     

施工总承包模式下建筑供应链成本管理优化决策模型研究

建筑供应链成本控制是建筑企业和业主进行工程项目管理的关键内容,在大型城市建设项目管理中尤其重要.本文分析了以施工总承包商为核心的建筑供应链的结构和特征,构建了该类建筑供应链的结构模型,对供应链中建筑材料供给、运输、劳务与专业分包、建筑产品建造等环节的费用情况进行详细分析;在考虑到运输商运输能力、供应商供给能力、分包商建造能力等约束的基础上,建立了以施工总包商为核心的建筑供应链成本的多因素综合决策优化模型,最后对模型的应用进行了案例分析,结果表明该模型对施工总承包模式下建筑供应链成本优化决策具有较好的指导性、实用性和可拓展型.