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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 600 for “"Crystallinity"”.
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Liquid crystallinity and alignment of ionic self-assembly complexes
In this work the first observation of new type of liquid crystals is presented. This is ionic self-assembly (ISA) liquid crystals formed by introduction of oppositely charged ions between different low molecular tectonic units. As practically all conventional liquid crystals consist of rigid core …
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Enhanced Structure and Crystallinity of Semiconducting Polymer Films Through Electrospray Deposition
… have been correlated with a higher degree of crystallinity as well as the film structure in the case of organic solar cells. The effects of different electrospray process parameters are investigated and various P3HT film structures are presented in this study. Electric repulsion present within …
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The optimization of the ZSM-5 catalyst activity with respect to crystallinity
… of zeolites optimization of factors such as crystallinity, which encapsulates morphology, and acidity can result in optimal activity. Optimal activity is vital in chemical industries due to the fact that it results in higher yields, better selectivities and lower operational costs. In this …
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Designing Functionality into Step-Growth Polymers from Liquid Crystallinity to Additive Manufacturing
Step-growth polymerization facilitates the synthesis of a wide range of industrially applicable polymers, such as polyesters and polysulfones. The choice of backbone and end group structure within these polymers drastically impacts the final material properties and processability emphasizing the …
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The influence of degree of crystallinity on the thermal conductivity of nylon 66
… to determine the extent to which the degree of crystallinity of nylon could be increased by cold-rolling and annealing, and the change :in thermal conductivity resulting from these treatments. A survey was made of the literature on the thermal conductivity of nylon in particular and non-metallic …
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Effect of Laser Induced Crystallinity Modification on Degradation and Drug Release of Biodegradable Polymer
… degradation and drug release are affected by its crystallinity. Control over PLLA crystallinity tailors drug release over time, and provides a potential solution to shorten the induction period of polymer degradation and drug release.The work presented in this thesis first investigates the …
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The effect of nanostructuring and crystallinity on triboelectric energy harvesting devices for biomedical applications
… temperatures to control the nanostructure and crystallinity of the resultant material. Devices using combinations of PLLA vs. PTFE and PLLA vs. P(VDF-TrFE) were investigated as biocompatible materials to use in TEGs to power medical devices. Characterisation of the materials used was carried …
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Effect of heat treatment on tensile properties, dyeability and crystallinity of nylon and polyester filament yarns
… technique, was used to calculate the degree of crystallinity as a structural parameter. Filament tensile strength and elongation at break were measured on a constant-rate-of-extension machine, and then toughness of the sample was obtained from the load elongation curve. The amount of dye uptake …
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Solute-Polymer States of Water and the Physico-Chemical Properties of Food Model Systems (Crystallinity, Sorption, Hysteresis, Starch)
The objective was first to study physico-chemical properties of solute-polymer mixtures as related to water binding, solute content and water activity (a(,w)). It was hypothesized that these properties were due to the presence of solute (SOL) and polymer (POL) water. The second objective was to …
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In situ spectroscopic ellipsometry studies of silicon film crystallinity and interface structure deposited by DC reactive magnetron sputtering
This work reports a systematic series of in situ spectroscopic ellipsometry (SE) studies on silicon film growth by reactive magnetron sputtering of a Si target in (Ar + H$\sb2$) at low temperatures ($\le$600$\sp\circ$C). The complete crystalline film growth zones have been identified for the first …
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The effect of cooling rate on toughness and crystallinity in poly(ether ketone ketone) (PEKK)/G30-500 composites
… to investigate the effect of cooling rate on crystallinity. A fifth panel was used to investigate the effect of annealing the composite after completion of the standard fabrication process. The sixth panel was used to investigate changes in toughness due to manufacturing towpreg with polymer …
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Characterization of the crystallinity and mechanical properties of CTFE & CTFE copolymeric films as a function of cooling rate and the implications on adhesion
… an important processing variable, affecting the crystallinity of the CTFE films which in turn affect many properties including dielectric characteristics and mechanical properties. In this study, the crystallinity of CTFE and CTFE copolymeric films as a function of cooling rate was characterized …
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Poly(L-Lactic Acid) Langmuir Monolayers at the Air/Water Interface and Langmuir-Blodgett Films on Solid Substrates: Phase Behavior, Surface Morphology, and Crystallinity
Controlling the surface morphology and degree of crystallinity of poly(L-lactic acid) (PLLA) substrates have recently attracted considerable attention because of their applications in cell adhesion, tissue engineering, and drug delivery. Several techniques have been used to fabricate PLLA …
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A numerical and experimental investigation of the effects of thermal history on the structure/property relationship of PPS/carbon fiber composites
… during cooling from the melt on the degree of crystallinity, morphology, and mechanical properties of (polyphenylenesulfide) PPS/carbon fiber composites. Three thermal treatments were employed in this study: isothermal crystallization from the melt at 140,160,180,200, and 220°C, quenching from …
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Investigação de redução da cristalinidade da celulose sob a influência de diferentes misturas eutéticas.
… that regulate cellulose access, such as the crystallinity index. Thus, reducing the crystallinity of cellulose is not a trivial process, due to its supramolecular structure which prevents the process from being carried out in conventional solvents. This work studied the reduction of the …
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Time Dependent Properties of Semicrystalline Poly(Arylene Ether Ether Ketone) (Peek) Above and Below the Glass Transition
… first time in this study. The evolution of the crystallinity during the secondary crystallization process was monitored by DSC and density measurements. Crystallinity was characterized according to the standard two-phase model of semicrystalline polymers and analyzed with respect to the failure …
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Steady State Modeling and Dynamic Analysis of Film Blowing
… than the effect of die swell. In addition, crystallinity is shown to have a stabilizing effect on the system, with more crystallinity dampening the effect of perturbations. Stability diagrams for each material and model show reasonable results, with higher blow-up ratios becoming unstable …
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Characterisation of freeze dried amino acids and gelatin based rapidly Disintegrating tablets
… time. In this study, the degree of amino acid crystallinity in gelatin/amino acid based RDTs was investigated using terahertz pulsed spectroscopy. Three amino acids were investigated: alanine (89 g mol-1), serine (105 g mol-1), and proline (115 g mol-1). The three amino acids were studied by …
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Static and Dynamic Thermal Behavior of Carbon Based Nanofluids
… Three types of CNTs with various degrees of crystallinity and surface energy were prepared using heat-treatment temperature. The thermal conductivity of nanofluids tested at varying concentration from 0% to 1.2% using static and dynamic thermal tests. The CNT type and volume concentration …
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