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Articles 1 - 7 of 7
Full-Text Articles in Engineering
Structure-Property Evolution During Polymer Crystallization, Deepak Arora
Structure-Property Evolution During Polymer Crystallization, Deepak Arora
Open Access Dissertations
The main theme of this research is to understand the structure-property evolution during crystallization of a semicrystalline thermoplastic polymer. A combination of techniques including rheology, small angle light scattering, differential scanning calorimetry and optical microscopy are applied to follow the mechanical and optical properties along with crystallinity and the morphology. Isothermal crystallization experiments on isotactic poly-1-butene at early stages of spherulite growth provide quantitative information about nucleation density, volume fraction of spherulites and their crystallinity, and the mechanism of connecting into a sample spanning structure. Optical microscopy near the fluid-to-solid transition suggests that the transition, as determined by time-resolved mechanical …
Diffusion And Structure In Complex Fluids: I. Axial Diffusion In Membranes Ii. Proteins In Ionic Liquids, Malvika Bihari
Diffusion And Structure In Complex Fluids: I. Axial Diffusion In Membranes Ii. Proteins In Ionic Liquids, Malvika Bihari
Open Access Dissertations
Geometrically hindered motions of a single large solute (particle or polymer) can be imaged in real time via optical microscopy. The dynamics of fluorescent colloidal particles near surfaces and in porous membranes were monitored using confocal microscopy. A method of analysis to estimate diffusivity of particles in the axial direction by observing their intensity fluctuations was developed. The intensity fluctuations correspond to the Brownian motion of the particles in the axial direction. The method was successful in capturing the hindered diffusion of particles close to surfaces and in pores. This study provides a novel route to monitor the dynamics of …
Catalytic Fast Pyrolysis Of Biomass For The Production Of Fuels And Chemicals, Torren Ryan Carlson
Catalytic Fast Pyrolysis Of Biomass For The Production Of Fuels And Chemicals, Torren Ryan Carlson
Open Access Dissertations
Due to its low cost and large availability lignocellulosic biomass is being studied worldwide as a feedstock for renewable liquid biofuels. Currently there are several routes being studied to convert solid biomass to a liquid fuel, which involve multiple steps at long residence times thus greatly increasing the cost of biomass processing. Catalytic fast pyrolysis (CFP) is a new promising technology to convert directly solid biomass to gasoline-range aromatics that fit into the current infrastructure. CFP involves the rapid heating of biomass (~500˚C sec-1) in an inert atmosphere to intermediate temperatures (400 to 600 ˚C) in the presence of zeolite …
Prediction And Manipulation Of Drop Size Distribution Of Emulsions Using Population Balance Equation Models For High-Pressure Homogenization, Neha B. Raikar
Prediction And Manipulation Of Drop Size Distribution Of Emulsions Using Population Balance Equation Models For High-Pressure Homogenization, Neha B. Raikar
Open Access Dissertations
Emulsions constitute a wide range of natural as well as processed products. Pharmaceutical applications of emulsions include oral administration, parenteral delivery, ophthalmic medicine, topical and transdermal creams, and fluorocarbon-in-water emulsions for blood oxygenation. In the foods area many of the products like mayonnaise, margarine, ice-creams are emulsions by nature and some products can also be used for delivery of active ingredients (e.g. nutraceuticals) with potential health benefits. Emulsions are also encountered at many stages of petroleum recovery, transportation, and processing. Typically, emulsions are manufactured in a two-step process. First a coarse emulsion called a premix is made which is passed …
Polymer Composites And Porous Materials Prepared By Thermally Induced Phase Separation And Polymer-Metal Hybrid Methods, Joonsung Yoon
Polymer Composites And Porous Materials Prepared By Thermally Induced Phase Separation And Polymer-Metal Hybrid Methods, Joonsung Yoon
Open Access Dissertations
The primary objective of this research is to investigate the morphological and mechanical properties of composite materials and porous materials prepared by thermally induced phase separation. High melting crystallizable diluents were mixed with polymers so that the phase separation would be induced by the solidification of the diluents upon cooling. Theoretical phase diagrams were calculated using Flory-Huggins solution thermodynamics which show good agreement with the experimental results. Porous materials were prepared by the extraction of the crystallized diluents after cooling the mixtures (hexamethylbenzene/polyethylene and pyrene/polyethylene). Anisotropic structures show strong dependence on the identity of the diluents and the composition of …
Quantifying Defects In Zeolites And Zeolite Membranes, Karl Daniel Hammond
Quantifying Defects In Zeolites And Zeolite Membranes, Karl Daniel Hammond
Open Access Dissertations
Zeolites are crystalline aluminosilicates that are frequently used as catalysts to transform chemical feedstocks into more useful materials in a size- or shape-selective fashion; they are one of the earliest forms of nanotechnology. Zeolites can also be used, especially in the form of zeolite membranes (layers of zeolite on a support), to separate mixtures based on the size of the molecules. Recent advances have also created the possibility of using zeolites as alkaline catalysts, in addition to their traditional applications as acid catalysts and catalytic supports. Transport and catalysis in zeolites are greatly affected by physical and chemical defects. Such …
Water-In-Oil Microemulsions: Counterion Effects In Aot Systems And New Fluorocarbon-Based Microemulsion Gels, Xiaoming Pan
Water-In-Oil Microemulsions: Counterion Effects In Aot Systems And New Fluorocarbon-Based Microemulsion Gels, Xiaoming Pan
Open Access Dissertations
Microemulsions have important applications in various industries, including enhanced oil recovery, reactions, separations, drug delivery, cosmetics and foods. We investigated two different kinds of water-in-oil microemulsion systems, AOT (bis(2-ethylhexyl) sulfosuccinate) microemulsions with various counterions and perfluorocarbon-based microemulsion gels with triblock copolymers. In the AOT systems, we investigated the viscosity and interdroplet interactions in Ca(AOT)2, Mg(AOT)2 and KAOT microemulsions, and compared our results with the commonly-studied NaAOT/water/decane system. We attribute the differences in behavior to different hydration characteristics of the counterions, and we believe that the results are consistent with a previously proposed charge fluctuation model. Perfluorocarbons (PFCs) are of interest …