957 resultados para Cotton manufacture
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Ancien possesseur : Argenson, Antoine-René de Voyer (1722-1787 ; marquis de Paulmy d')
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The main objectives of the investigations reported in the present thesis are the following: (1) to find out some industrial wastes as cheaper additives to augment the air-blowing polymerization process of bitumen. This will bring down the cost of production of industrial bitumen which can be applied for the manufacture of bitumenous paints, roofing and flooring materials etc. (2) to find out suitable promoters for the above additives. This will bring down the consumption of the additives (3) to help in the industrial pollution control (4) to investigate the usefulness of the industrial bitumen produced in the production of bituminous paints (5) to find out thekinetic parameters of the reactions invovled with different additives. This is essential for the design, construction and operation of new industrial bitumen plants using the additives investigated. This will also enable us to establish the mechanism of the reactions involved in the process
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Polydimethylsiloxane (PDMS) is the elastomer of choice to create a variety of microfluidic devices by soft lithography techniques (eg., [1], [2], [3], [4]). Accurate and reliable design, manufacture, and operation of microfluidic devices made from PDMS, require a detailed characterization of the deformation and failure behavior of the material. This paper discusses progress in a recently-initiated research project towards this goal. We have conducted large-deformation tension and compression experiments on traditional macroscale specimens, as well as microscale tension experiments on thin-film (≈ 50µm thickness) specimens of PDMS with varying ratios of monomer:curing agent (5:1, 10:1, 20:1). We find that the stress-stretch response of these materials shows significant variability, even for nominally identically prepared specimens. A non-linear, large-deformation rubber-elasticity model [5], [6] is applied to represent the behavior of PDMS. The constitutive model has been implemented in a finite-element program [7] to aid the design of microfluidic devices made from this material. As a first attempt towards the goal of estimating the non-linear material parameters for PDMS from indentation experiments, we have conducted micro-indentation experiments using a spherical indenter-tip, and carried out corresponding numerical simulations to verify how well the numerically-predicted P(load-h(depth of indentation) curves compare with the corresponding experimental measurements. The results are encouraging, and show the possibility of estimating the material parameters for PDMS from relatively simple micro-indentation experiments, and corresponding numerical simulations.
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This paper describes some of the results of a detailed farm-level survey of 32 small-scale cotton farmers in the Makhathini Flats region of South Africa. The aim was to assess and measure some of the impacts (especially in terms of savings in pesticide and labour as well as benefits to human health) attributable to the use of insect-tolerant Bt cotton. The study reveals a direct cost benefit for Bt growers of SAR416 ($51) per hectare per season due to a reduction in the number of insecticide applications. Cost savings emerged in the form of lower requirements for pesticide, but also important were reduced requirements for water and labour. The reduction in the number of sprays was particularly beneficial to women who do some spraying and children who collect water and assist in spraying. The increasing adoption rate of Bt cotton appears to have a health benefit measured in terms of reported rates of accidental insecticide poisoning. These appear to be declining as the uptake of Bt cotton increases. However, the understanding of refugia and their management by local farmers are deficient and need improving. Finally, Bt cotton growers emerge as more resilient in absorbing price fluctuations.
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This paper presents the results of a study aimed at measuring the economic impact of genetically modified cotton in Maharashtra State, India. It is the first study of its kind in India in that the data have been collected from farmers growing the crop under market conditions, rather than from trials. The research compares the performance of more than 9,000 Bt and non-Bt cotton farm plots in Maharashtra over the 2002 and 2003 growing seasons. Results show that Bt cotton varieties have had a significant positive impact on average yields and on the economic performance of cotton growers.