Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 86 for “"Polyvinyl alcohol"”.
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Polyvinyl alcohol size recovery and reuse via vacuum flash evaporation
Polyvinyl alcohol (PVA) desize effluent is a high COD contributor to towel manufacturing plant's Primary Oxygenation Treatment of Water operation, and being non-biodegradable, is a threat to the environment. When all-PVA/wax size is used in weaving, significant incentives exist to recover the …
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Numerical Modeling of Polyvinyl Alcohol (PVA) Swelling and Dissolution in Water
… high performance dissolvable elastomer from Polyvinyl Alcohol (PVA) replacing current not dissolvable rubber based materials. With fast development of hydraulic-fracturing in past 15 years, the oil and gas industry is in great need of dissolvable materials to fabricate certain temporary …
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Three-Dimensional Direct Ink Writing of Low Viscosity Inks in a Polyvinyl Alcohol Suspension
… for low-viscosity nanomaterial inks composed of polyvinyl alcohol (PVA) as matrix and various nanomaterial fillers in forming 3D gel structures. This methodology can be extrapolated to other material systems without the requirement of supporting structure in maintain structural integrity. In this …
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A study of the relation between molecular weight distribution and mechanical properties of polyvinyl alcohol
… properties and molecular weight distribution of polyvinyl alcohol was carried out. The polyvinyl alcohol was fractionated with respect to degree of polymerization (D.P.) by precipitation of the fractions from 2% solution in water with a n-propyl alcohol-water nonsolvent. The initial small scale …
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LIQUID PLASTICS AS A NEW ENVIRONMENTAL PROBLEM? AN INTEGRATED RISK ASSESSMENT OF POLYVINYL ALCOHOL, POLYETHYLENE GLYCOL, POLYVINYL PYRROLIDONE AND POLYACRYLIC ACID
… the ecotoxicity of four commonly used WSPs—polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and polyacrylic acid (PAA)—using the freshwater fish Danio rerio and the crustacean Daphnia magna as model organisms. The impacts were assessed at multiple levels of …
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Design of High Efficiency Fibers for Ion Exchange and Heavy Metal Removal
… used to chemically modify and characterize a polyvinyl alcohol mercaptyl fibrous system, coated on a fiberglass substrate, for the purpose of arsenite (As3+) removal from water. Physical/chemical aspects of naturally occurring thiols and disulfides was used to draw parallels to observations …
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The Dynamical Behavior of Confined Aqueous Systems
… behavior of artificial tear films (polyvinyl alcohol aqueous solutions) and synovial fluids was of scientific importance for future medical ramifications. The effects of chemical additives, ionic strength and adjoining surface chemistry on the static and dynamic interactions of …
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Heat and Mass Transfer Characteristics of Desiccant Polymers
… were initially studied. It was decided that polyvinyl alcohol best met the pre-determined selection criteria. After the focus material was chosen, numerical models representing two heat and mass transfer applications were created. One-dimensional numerical models were developed for the …
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Composite hydrogel-nanofibre vessels for vascular graft applications
… Firstly, the feasibility of preparing polyvinyl alcohol (PVA) based hydrogels with controllable mechanical property was investigated. Three PVA based hydrogels were prepared by blending PVA with chitosan, gelatin or starch and by treatment with freeze-thaw cycles and coagulation. The …
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Development of a Novel Grease Resistant Functional Coatings for Paper-based Packaging and Assessment of Application by Flexographic Press
… grease resistant functional coating comprised of polyvinyl alcohol (PVA), sodium tetraborate pentahydrate (borate) and acetonedicarboxylic acid (ACDA) and the application of said coating by means of flexographic press is presented herein. Application criteria is developed, testing procedures …
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Electrokinetic separations involving surfactants and proteins
… migration times of the proteins the addition of polyvinyl alcohol to the sample was also investigated. The polyvinyl alcohol improved reproducibility by reversibly covering the active sites on the capillary surface to minimize protein interactions. Migration time reproducibility was also improved …
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Study of Mechanical Properties of PVA Fiber-Reinforced Concrete With Raman Spectroscopic Analysis
… strength after casting into cubes. The effect of polyvinyl alcohol fibers on the mechanical properties of concrete was also studied. The impacts of moisture and the stress applied on the fibers were determined using Raman spectroscopy.</p>
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Synthesis and Characterization of Linear and Branched Polylactic Acid for Use in Food Packaging Applications
… various plasticizers and surfactants as well as polyvinyl alcohol as dispersing agents. A cold dispersion procedure realized the most success, as a 15% PLA waterborne formulation was achieved. Standard test methods show a high degree of grease resistance for the formulated coatings. A hot melt …
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Extraction of Heavy Metals from Aqueous Solutions using Chitosan/Montmorillonite Hybrid Hydrogels
… of the hydrogels is improved by introducing polyvinyl alcohol (PVA) and increasing the cross-linking agent. Interestingly, the increment of MMT content also enhances the mechanical strength of the hydrogels. Adsorption study is performed with Cu(II) to evaluate the effects of pH and Cu(II) …
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DEVELOPMENT OF SELF-HEALING SUSTAINABLE CONCRETE USING RECYCLED MATERIALS
… ground granulated blast furnace slag (GGBS) and polyvinyl alcohol (PVA) fiber in terms of flexural strength recovery and crack sealing behavior. 50% GGBS-blended concrete was found to have good autogenous healing ability and the addition of PVA fibers indirectly further increases the …
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Hybrid fuel cell for mobile devices : an integrated approach
… (MEA). In addition, an MEA was modified using polyvinyl alcohol (PVA) to test its effect on decreasing methanol crossover for improved fuel cell performance.
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Magnetic adsorbents displaying switchable ion-exchange behaviour
… polyelectrolyte surfaces on low cost non-porous polyvinyl alcohol-magnetite supports. Grafting of poly(2-vinyl pyridine) and poly(methacrylic acid) was fully characterised using solid and liquid state FTIR. Dense polyelectrolyte layers were seen, with Ce(IV) grafted layers accounting for up to …
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Development of Thin-Film Composite Membranes Incorporated With Graphene Oxide and Derivatives for Forward Osmosis Processes
… derivatives on the modified membranes. First, polyvinyl alcohol (PVA)/GO hydrogel was coated on the PA surface to improve the membrane anti-fouling property. Second, the GO flake’s lateral size was reduced to decrease PA defects and improve membrane performance. Next, Aquaporin was added with …
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