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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

[en] RHEOLOGICAL CHARACTERIZATION OF WATER-OIL EMULSIONS / [pt] CARACTERIZAÇÃO REOLÓGICA DE EMULSÕES DE ÁGUA EM ÓLEO

CARLA NUNES DE OLIVEIRA NICOLEIT 08 July 2015 (has links)
[pt] As emulsões se formam naturalmente nos reservatórios e durante a exploração do petróleo. A presença de agentes tensoativos, principalmente nos óleos pesados, ajuda na sua estabilização. A alta viscosidade dos óleos pesados gera uma maior dificuldade da sua exploração, e por isso o conhecimento da emulsão formada com esse óleo reduz seu custo de produção. O tipo de emulsão formada, o tamanho de gota e sua distribuição afetam o comportamento reológico da emulsão. Neste trabalho, emulsões foram criadas a partir de um óleo sintético newtoniano de viscosidade próxima à de um óleo pesado. A água utilizada na formação das emulsões era deionizada e com diferentes surfactantes. As características reológicas das emulsões foram medidas. Em sua maioria as caracterizações reológicas foram feitas a 10 graus Celcius, através de testes oscilatórios de pequena amplitude, testes de escoamento permanente, e testes de fluência. Todas as emulsões eram de água em óleo, formadas com 80 por cento de óleo. O tamanho das gotas de água era da ordem de 10 microns. As emulsões apresentaram comportamento elástico-dominante no regime viscoelástico linear. Os resultados dos testes de regime permanente mostraram que a viscosidade das emulsões é bem descrita pelo modelo de Herschel-Bulkley. Foram feitos testes de regime permanente também a 4 graus Celcius, para investigar a influência da temperatura na viscosidade, mas nenhuma mudança significativa foi observada. Finalmente, testes de fluência foram feitos com o objetivo de determinar a tensão limite de escoamento das emulsões. / [en] Emulsions are formed naturally in the reservoirs and during oil exploration, and the surfactants primarily present in heavy oil, helps its stabilization. The high viscosity of heavy oil generates greater difficulty on the operation, so the knowledge of the emulsion formed with this kind of oil reduces its cost of production. The type of emulsion formed, the droplet size and its distribution affect the rheology of the emulsion. in this work, emulsions were created with a Newtonian synthetic oil whose viscosity is close to the one of a heavy oil. The water employed in the emulsion preparation was deionized and contained different surfactants. Rheological characterizations were performed at 10 degrees Celcius in most cases, and included small-amplitude oscillatory tests, steady-state flow tests and creep tests. All emulsions were oil-in-water, and were composed of 80 per cent of oil. The water droplet size was about 10 microns. The emulsions exhibited a predominantly elastic behavior in the linear viscoelastic regime. The steady-state flow test results showed that the emulsions possess tests and the results showed that the emulsion viscosity is well described by the Herschel-Bulkley model. Some tests were also done at 4 degrees Celcius, to investigate the influence of temperature on viscosity, but no significant change was found. Finally, creep tests were performed to determine the yield stress of the emulsions.
152

The decay modes of hypernuclei

Ismail, Abu Zafar Mohammed January 1964 (has links)
No description available.
153

Targeted Delivery of Surfactants to the Oil-Water Interface Via Halloysite Nanotubes for Oil Spill Remediation

January 2020 (has links)
archives@tulane.edu / 1 / Azeem Farinmade
154

Comparison of Intravenous Lipid Emulsions in Parenteral Nutrition: A Pilot Study

McGuigan, Alexis K. 02 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Background: SMOF lipid™ infusion containing soybean oil, medium-chain triglycerides, olive oil, and fish oil has been approved and recommended for use in adults receiving parenteral nutrition (PN). Research shows that SMOF lipid infusion is safe for use in post-operative and critically ill patients. Improved patient outcomes are linked to SMOF lipid use over traditional soybean oil lipid emulsions. Objective: The purpose of this study was to determine the effect of SMOF lipid infusion on incidence of infection, ICU length of stay, hospital length of stay, and mortality in adult trauma patients as compared to parenteral nutrition utilizing 100% soybean oil emulsion or a lipid-free, dextrose and amino acid administration. Methods and Analysis: A retrospective chart review was conducted for adult trauma patients admitted to Eskenazi Health’s surgical intensive care unit (SICU) that received PN from May 2017 to May 2020. Data were collected from the electronic health record and trauma registry. Results: Twenty-nine patients were included who met study criteria: 17 patients in the traditional lipid cohort and 12 in the SMOF lipid cohort. The length of PN therapy was comparable between the traditional and SMOF ILE groups, 13.9 days (± 11.5) and 13.3 days (± 14.3) respectively. All 12 patients in the SMOF lipid cohort received intravenous lipid emulsion (ILE) compared to 42% (n=7) of traditional lipid group patients (p=0.001). SMOF treatment group were provided 100% of estimated energy needs via PN compared to an average of 94% (± 9.7) of estimated energy needs in the traditional lipid treatment group (p=0.036). Incidence of infection during initial hospitalization was significantly lower in the SMOF treatment group (n=3, 25%) compared to the traditional lipid treatment group (n=13, 76%). Mortality was decreased in the SMOF treatment group (0%) when contrasted to the Intralipid treatment group (23.5%), p=0.04. Conclusion: Patients receiving SMOF lipid emulsion within PN therapy had better clinical outcomes compared to those receiving Intralipid soybean-lipid emulsion or a dextrose and amino acid administration.
155

Dynamics from an equilibrium lattice model of a microemulsion

Qi, Songyun 01 January 1999 (has links)
A 3D lattice model of three-component microemulsion employed previously to describe the equilibrium phase behavior has been extended to investigate the nonequilibrium dynamics of such system. The model is based on "Dynamical Monte Carlo" simulations which apply a coarse-grained velocity field onto a conventional Monte Carlo lattice, so as to represent realistically interactions between particles, and which permits the observation of time-dependent behavior. The results for viscosity are obtained by applying the velocity gradient onto the system. The simulations are performed over a range of shear rates and temperatures. Compared to the oil-rich (water-rich) phase, the microemulsion phase shows a typical (non-Newtonian) behavior and considerably lower viscosity at a given temperature. Both phases exhibit the characteristic viscosity decrease with an increase in temperature. The velocity auto-correlation function of a microemulsion phase is found to follow a Kohlrausch-Wiliams-Watts (KWW) stretched-exponential law, rather than a simple exponential decay. The stretched exponent is related to the normal, inhibited and enhanced diffusion behaviors of the system.
156

Laboratory evaluation of surface treatments to asphaltic pavements in Mississippi

Jordan, Walter Stephens 01 May 2010 (has links)
Chip and scrub seal treatments are one of the most common pavement preservation practices, however, no performance specifications exist in Mississippi. Review of literature has shown the treatment of cores being successful in reducing the viscosity of aged asphalt pavements. The purpose of this thesis is to provide a basis for performance based specifications for surface treatments in Mississippi. This thesis provides information pertaining to viscosity, moisture loss, and frosted marble analysis of emulsions and the effects of rejuvenation after application of emulsions to aged asphalt pavements which are vital to the performance of the surface treatment. The objectives to this thesis are to determine and evaluate the effects of rejuvenation, frosted marble test, and moisture loss of emulsion applied to aged asphalt pavements. Results from these analysis’ are favorable for developing or providing a basis for performance based specifications for surface treatments applied in Mississippi.
157

Optimization and evaluation of a pectin-based composite coating on mango and cucumber

Moalemiyan, Mitra. January 2008 (has links)
No description available.
158

Water-in Water (W/W) Emulsion Drug Delivery Systems

Sharma, Anita 09 August 2013 (has links)
No description available.
159

Effects of emulsifiers on properties of microemulsions and polymeric emulsions

Lin, Ching-Sheng January 1994 (has links)
No description available.
160

In vitro drug release from W/O/W multiple emulsions /

Ng, Shirley Mei-king January 1980 (has links)
No description available.

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