844 resultados para Dyes and dyeing--Textile fabrics
Resumo:
This paper examines the current role of women in the clothing and textile industry through oral history of South African union members. I argue that the industry’s particularly exploitative environment is directly related to both gender and globalization, acting together to worsen conditions in factories. Additionally, I argue that the more recent addition of an increasingly consumer-driven industry structure also impacts its abusive environment. Unionization, along with public and private regulation, have the potential to be catalysts for change in the industry. To be most effective, these organizations need to take into account both gender and globalization, and recognize the equal impacts both have when making decisions.
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In 2009 Avella created a series of innovative fabrics for the Yves St Laurent (YSL) collection, deploying techniques from vehicle engineering to generate new materials for a range of garments. Studying the bonding of layers of material in ceramic plate thermobonding technology, Avella conducted a series of experiments with textiles such as flannel, silk and synthetics, and material such as leather, layered with polyamide foam and textile substrate to create new, textured and insulating fabrics with beautiful surfaces and interesting forms. The lightweight properties of the foam enabled the maximum insulation/weight ratio, and the panel moulding technology brought new forms of draping prêt-a-porter fashion design. Exclusive to YSL, this technique was patented and then shown at the Premiere Vision textiles trade fair in 2010. Much documented in specialist journals this innovation also breached the trade-culture barrier and was reported and documented in mainstream newspapers (New York Herald Tribune). Avella’s background in textile workshop studio experimentation at the RCA brought to YSL textiles research for manufacture, the innovative collaboration between fashion couture and engineering laboratory experiments from vehicle design.
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In this research, micro and nanoparticles of Spirulina platensis dead biomass were obtained, characterized and employed to removal FD&C red no. 40 and acid blue 9 synthetic dyes from aqueous solutions. The effects of particle size (micro and nano) and biosorbent dosage (from 50 to 750 mg) were studied. Pseudofirst order, pseudo-second order and Elovich models were used to evaluate the biosorption kinetics. The biosorption nature was verified using energy dispersive X-ray spectroscopy (EDS). The best results for both dyes were found using 250 mg of nanoparticles, in these conditions, the biosorption capacities were 295 mg g−1 and 1450 mg g−1, and the percentages of dye removal were 15.0 and 72.5% for the FD&C red no. 40 and acid blue 9, respectively. Pseudo-first order model was the more adequate to represent the biosorption of both dyes onto microparticles, and Elovich model was more appropriate to the biosorption onto nanoparticles. The EDS results suggested that the dyes biosorption onto microparticles occurred mainly by physical interactions, and for the nanoparticles, chemisorption was dominant.
Resumo:
Adsorption of food dyes acid blue 9 and food yellow 3 onto chitosan was optimized. Chitosan was obtained from shrimp wastes and characterized.Afull factorial design was used to analyze the effects of pH, stirring rate and contact time in adsorption capacity. In the optimal conditions, adsorption kinetics was studied and the experimental data were fitted with three kinetic models. The produced chitosan showed good characteristics for dye adsorption. The optimal conditions were: pH 3, 150rpm and 60 min for acid blue 9 and pH 3, 50rpm and 60 min for food yellow 3. In these conditions, the adsorption capacities values were 210mgg−1 and 295mgg−1 for acid blue 9 and food yellow 3, respectively. The Elovich kinetic model was the best fit for experimental data and it showed the chemical nature of dyes adsorption onto chitosan.
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Syrups with high sugar content and dehydrated fruits in its composition can be added to chocolate fillings to reduce the need of artificial flavor and dyes attributing a natural appeal to the product. Fruit bases were produced with lyophilized strawberry, passion fruit, and sliced orange peel. Rheological dynamic oscillatory tests were applied to determine the products stability and tendency of shelf life. Values of G´< G´´ were observed for strawberry and passion fruit flavor, whereas values of G´ > G´´ were found for orange flavor during the 90 days of storage. It was observed that shear stress values did not vary significantly suggesting product stability during the studied period. For all fillings, it was found a behavior similar to the fruit base indicating that it has great influence on the filling behavior and its stability. The use of a sugar matrix in fillings provided good shelf life for the fruit base, which could be kept under room temperature conditions for a period as long as one year. The good stability and storage conditions allow the use of fruit base for handmade products as well as for industrialized products.
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The thermo-solvatochromism of 2,6-dibromo-4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePMBr(2), has been studied in mixtures of water, W, with ionic liquids, ILs, in the temperature range of 10 to 60 degrees C, where feasible. The objectives of the study were to test the applicability of a recently introduced solvation model, and to assess the relative importance of solute-solvent solvophobic interactions. The ILs were 1-allyl-3-alkylimidazolium chlorides, where the alkyl groups are methyl, 1-butyl, and 1-hexyl, respectively. The equilibrium constants for the interaction of W and the ILs were calculated from density data; they were found to be linearly dependent on N(C), the number of carbon atoms of the alkyl group; van't Hoff equation (log K versus 1/T) applied satisfactorily. Plots of the empirical solvent polarities, E(T) (MePMBr(2)) in kcal mol(-1), versus the mole fraction of water in the binary mixture, chi(w), showed non-linear, i.e., non-ideal behavior. The dependence of E(T) (MePMBr(2)) on chi(w), has been conveniently quantified in terms of solvation by W, IL, and the ""complex"" solvent IL-W. The non-ideal behavior is due to preferential solvation by the IL and, more efficiently, by IL-W. The deviation from linearity increases as a function of increasing N(C) of the IL, and is stronger than that observed for solvation of MePMBr(2) by aqueous 1-propanol, a solvent whose lipophilicity is 12.8 to 52.1 times larger than those of the ILs investigated. The dependence on N(C) is attributed to solute-solvent solvophobic interactions, whose relative contribution to solvation are presumably greater than that in mixtures of water and 1-propanol.
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A saddle shaped tetracluster porphyrin species containing four [Ru(3)O(OAc)(6)(py)(2)](+) clusters coordinated to the N-pyridyl atoms of 5,10,15,20-tetra(3-pyridyl)porphyrin, H(2)(3-TCPyP), has been investigated in comparison with the planar tetra(4-pyridyl) porphyrin analogue H(2)(4-TCPyP). The steric effects from the bulky peripheral complexes play a critical role in the H(2)(3-TCPyP) species, determining a non-planar configuration around the porphyrin centre and precluding any significant pi-electronic coupling, in contrast with the less hindered H(2)(4-TCPyP) species. Both systems exhibit a photoelectrochemical response in the presence of nanocrystalline TiO(2) films, involving the porphyrin excitation around 450 nm. However, only in the H(2)(4-TCPyP) case do the cluster moieties also contribute to the photoinduced electron injection process at 670 nm, reflecting the relevance of the electronic coupling between the porphyrin centre and the peripheral complexes.
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Protein kinase C beta II (PKC beta II) levels increase in the myocardium of patients with end-stage heart failure (HF). Also targeted overexpression of PKC beta II in the myocardium of mice leads to dilated cardiomyopathy associated with inflammation, fibrosis and myocardial dysfunction. These reports suggest a deleterious role of PKC beta II in HF development. Using a post-myocardial infarction (MI) model of HF in rats, we determined the benefit of chronic inhibition of PKC beta II on the progression of HF over a period of 6 weeks after the onset of symptoms and the cellular basis for these effects. Four weeks after MI, rats with HF signs that were treated for 6 weeks with the PKC beta II selective inhibitor (beta IIV5-3 conjugated to TAT(47-57) carrier peptide) (3 mg/kg/day) showed improved fractional shortening (from 21% to 35%) compared to control (TAT(47-57) carrier peptide alone). Formalin-fixed mid-ventricle tissue sections stained with picrosirius red, haematoxylin and eosin and toluidine blue dyes exhibited a 150% decrease in collagen deposition, a two-fold decrease in inflammation and a 30% reduction in mast cell degranulation, respectively, in rat hearts treated with the selective PKC beta II inhibitor. Further, a 90% decrease in active TGF beta 1 and a significant reduction in SMAD2/3 phosphorylation indicated that the selective inhibition of PKC beta II attenuates cardiac remodelling mediated by the TGF-SMAD signalling pathway. Therefore, sustained selective inhibition of PKC beta II in a post-MI HF rat model improves cardiac function and is associated with inhibition of pathological myocardial remodelling.
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The concentration of hydrogen peroxide is an important parameter in the azo dyes decoloration process through the utilization of advanced oxidizing processes, particularly by oxidizing via UV/H2O2. It is pointed out that, from a specific concentration, the hydrogen peroxide works as a hydroxyl radical self-consumer and thus a decrease of the system`s oxidizing power happens. The determination of the process critical point (maximum amount of hydrogen peroxide to be added) was performed through a ""thorough mapping"" or discretization of the target region, founded on the maximization of an objective function objective (constant of reaction kinetics of pseudo-first order). The discretization of the operational region occurred through a feedforward backpropagation neural model. The neural model obtained presented remarkable coefficient of correlation between real and predicted values for the absorbance variable, above 0.98. In the present work, the neural model had, as phenomenological basis the Acid Brown 75 dye decoloration process. The hydrogen peroxide addition critical point, represented by a value of mass relation (F) between the hydrogen peroxide mass and the dye mass, was established in the interval 50 < F < 60. (C) 2007 Elsevier B.V. All rights reserved.
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This article presents the use of fibers residue from textile industry to minimize environmental problems associated with material accumulation. Composite materials utilizing textile fiber residues and high density polyethylene were prepared. Effect of treatment with hot water on fibers to prepare composites was studied to provide an improvement in mechanical properties of these materials. This treatment on fibers was evaluated by X-ray diffraction and scanning electron microscopy techniques. Experimental results of mechanical properties indicated higher mechanical strength for treated fiber composites compared to the untreated fiber composites.
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The possibility of producing valued devices from low cost natural resources is a subject of broad interest. The present study explores the preparation and characterization of silk fibroin dense membranes using waste silk fibers from textile processing. Morphology, crystallinity, thermal resistance and cytotoxicity of membranes as well as the changes on the secondary structure of silk fibroin were analyzed after undergoing treatment with ethanol. Membranes presented amorphous patterns as determined via X-ray diffraction. The secondary structure of silk fibroin on dense membranes was either random coil (silk I) or p-sheet (silk II), before and after ethanol treatment, respectively. The sterilized membranes presented no cytotoxicity to endothelial cells during in vitro assays. This fact stresses the material potential to be used in the fabrication of biomaterials, as coatings of cardiovascular devices and as membranes for wound dressing or drug delivery systems. (C) 2010 Elsevier Ltd. All rights reserved.