This study investigated the formulation and characterisation of emulsion explosives. This included the manufacture of more than 120kg of emulsion explosive of which around 105kg was used on the explosive ordnance range in over 350 individual firings. For each emulsion composition, an average of eight firings was undertaken with which to substantiate the explosive performance data. The formulation was varied to determine the effects of water content upon the physical characteristics of the emulsion. These physical effects included thermal conductivity, particle size, viscosity and the explosive performance of the emulsion. In respect of explosive performance, microballoons were added to sensitise the emulsion and the proportions of microballoons added were altered to look at their effect on velocity of detonation, sensitivity and the brisance of the emulsions. Emulsion explosives are commonly referred, in literature, as Type 11 non-ideal explosives. This is due to their non-linear behaviour with respect to the variation of velocity of detonation with density. Traditionally, when an emulsion explosive was commercially manufactured, the water content has been kept at a minimum (12-17%). This was accepted as the way to achieve the best explosive performance, based upon the belief that an emulsion with the highest concentration of active ingredients, ammonium nitrate and oil, would give the best explosive performance. This study examined a wider range of emulsion explosive water contents than has been previously studied, from 12% to 35% water. It was found, during this study, that higher water content emulsions, specifically 25% water, had a marked increase in explosive performance. The highest velocity of detonation recorded was in a 39mm diameter tube, at 25% water content with 3% microballoons, was 5558ms-1. This was some 15% higher than any other VOD recorded in this study. The high velocity of detonation, at 25% water content, was one of a number of physical characteristics in which this water content varied from the other emulsion water contents. This study endeavored to show that emulsion explosives could exhibit two differing types of explosive reaction, thermal explosion and grain burning. This was based on the velocity of detonation and plate dent data, both of which indicated that there was a change in reaction with water content. Emulsion explosives, with a high water and high microballoon content, exhibited a thermal explosion type reaction. They exhibited Type I ideal explosive behaviour, with increasing velocity of detonation with density. Lower water content emulsion explosives, displayed the more commonly expected Type 11 non-ideal behaviour and reacted in a grain burning type detonation.

O processo de separação da água em emulsões de petróleo é feita durante o processamento primário do petróleo e consiste na coalescência de gotas de água. Para minimizar o uso de desemulsificantes e acelerar o processo de separação da emulsão alguns equipamentos podem ser utilizados como os separadores acústicos. Neste trabalho a técnica de força de radiação produzida por ondas estacionárias de ultrassom é aplicada na segregação das fases líquidas de emulsões água em óleo. São desenvolvidas células de ultrassom que operam em frequências próximas de 1 MHz através de ressonadores piezelétricos visando a aplicação na coalescência de gotas de água em emulsões do tipo água-óleo. O trabalho envolve simulações do campo acústico através de modelos analíticos unidimensionais e bidimensionais e de um modelo numérico bidimensional pelo método dos elementos finitos para o estado plano de deformações. São realizadas verificações experimentais em protótipos de células de alta potência para separação em batelada através da comparação do potencial de radiação acústica e da impedância elétrica com resultados de modelos computacionais. Diversos ensaios de quebra de emulsões sintetizadas de petróleo são realizados utilizando um aparato experimental de laboratório aplicando potências de até 600 W=l. Um sistema de controle de frequência de operação é implementado para manter máxima transmissão de potência elétrica para a célula. Os resultados mostraram que a técnica empregada pode reduzir pela metade o uso de desemulsificante químico (de 20 a 10 ppm) ou diminuir o tempo de residência em até 60% (de 20 para 8 min). Uma análise da influência da frequência na eficiência de desemulsificação é realizada e indica que não há sensibilidade no resultado para a faixa de frequência entre 0.8 e 1.5 MHz a uma temperatura ambiente de aproximadamente 23 C. A metodologia empregada auxilia no projeto das células e na aplicação da técnica, mas é insuficiente para explicar integralmente os mecanismos de separação e as diferenças entre o protótipo e o modelo. A aplicação de ultrassom na coalescência de emulsões possui potencial para desenvolvimento em larga escala. / The oil water separation process of petroleum emulsions is performed during the primary processing of crude oil and consists of water droplets coalescence. To minimize the use of demulsifiers and accelerate the emulsion separation process some equipment may be used such as acoustic separators. In this work, a radiation force technique produced by ultrasound standing waves is applied to the water phase separation in oil emulsions. Ultrasound cells operating at ultrasonic frequencies near 1 MHz are developed using piezoelectric resonators applied to the coalescence of water droplets in oil emulsions. This work involves simulations of the acoustic field through one-dimensional and two-dimensional analytical models and a numerical model for two-dimensional plane strain finite element analysis. Furthermore, experimental verification is performed using high power prototypes for batch separation by comparing the acoustic radiation potential and electrical impedance with computational models results. Several tests of synthesized petroleum emulsions breaking are performed using an experimental laboratory apparatus applying up to 600 W=l. A frequency control system is implemented in order to maintain maximum electric power transmission to the cells. The results showed that the technique can halve the use of chemical demulsifier (from 20 to 10 ppm) or decrease the residence time of up to 60% (from 20 to 8 min). An analysis of the frequency influence on demulsification efficiency is performed and indicates that there is no parameter sensitivity in the frequency range between 0.8 and 1.5 MHz at room temperature of approximately 23 C. It is demonstrated that the design methodology is consistent and the application has potential for large-scale development.

No description available.

This study investigated the formulation and characterisation of emulsion explosives. This included the manufacture of more than 120kg of emulsion explosive of which around 105kg was used on the explosive ordnance range in over 350 individual firings. For each emulsion composition, an average of eight firings was undertaken with which to substantiate the explosive performance data. The formulation was varied to determine the effects of water content upon the physical characteristics of the emulsion. These physical effects included thermal conductivity, particle size, viscosity and the explosive performance of the emulsion. In respect of explosive performance, microballoons were added to sensitise the emulsion and the proportions of microballoons added were altered to look at their effect on velocity of detonation, sensitivity and the brisance of the emulsions. Emulsion explosives are commonly referred, in literature, as Type 11 non-ideal explosives. This is due to their non-linear behaviour with respect to the variation of velocity of detonation with density. Traditionally, when an emulsion explosive was commercially manufactured, the water content has been kept at a minimum (12-17%). This was accepted as the way to achieve the best explosive performance, based upon the belief that an emulsion with the highest concentration of active ingredients, ammonium nitrate and oil, would give the best explosive performance. This study examined a wider range of emulsion explosive water contents than has been previously studied, from 12% to 35% water. It was found, during this study, that higher water content emulsions, specifically 25% water, had a marked increase in explosive performance. The highest velocity of detonation recorded was in a 39mm diameter tube, at 25% water content with 3% microballoons, was 5558ms-1. This was some 15% higher than any other VOD recorded in this study. The high velocity of detonation, at 25% water content, was one of a number of physical characteristics in which this water content varied from the other emulsion water contents. This study endeavored to show that emulsion explosives could exhibit two differing types of explosive reaction, thermal explosion and grain burning. This was based on the velocity of detonation and plate dent data, both of which indicated that there was a change in reaction with water content. Emulsion explosives, with a high water and high microballoon content, exhibited a thermal explosion type reaction. They exhibited Type I ideal explosive behaviour, with increasing velocity of detonation with density. Lower water content emulsion explosives, displayed the more commonly expected Type 11 non-ideal behaviour and reacted in a grain burning type detonation.

Hidrolisados proteicos possuem propriedades terapêuticas e são absorvidos mais facilmente pelo organismo quando comparados às proteínas, no entanto sua aplicação em alimentos é dificultada por serem higroscópicos, reativos e apresentarem gosto amargo. A microencapsulação por spray chilling pode ser uma alternativa para solucionar essas limitações. Este método de encapsulação consiste na atomização de uma mistura, formada pela dispersão ou emulsão do material ativo com o carreador fundido, em uma câmara com temperatura inferior ao ponto de fusão do carreador, que nessas condições solidifica, formando micropartículas esféricas. O objetivo deste trabalho foi elaborar micropartículas de hidrolisado de proteína de soja utilizando o método de spray chilling e gordura vegetal (PF 51°C) como carreador. Foram realizados ensaios para obtenção das micropartículas avaliando a alimentação por emulsão e dispersãoe diferentes formulações variando a proporção material ativo:encapsulante (1:5 e 1:10), velocidades de rotação no ultra-turrax (6000 e 8000 rpm) e três diferentes temperaturas (60, 70 e 80°C), totalizando dezoito tratamentos. As misturas foram submetidas à análise reológica para determinação de viscosidade e após serem atomizadas em spray chiller as micropartículas obtidas foram caracterizadas por FTIR, Difração de Raio-X, distribuição e tamanho médio por difração a laser e morfologia por microscopia eletrônica de varredura e confocal. Foram obtidas micropartículas lipídicas sólidas esféricas e aglomeradas, o tamanho médio variou de 53,06 ± 2,17 µm e 68,03 ± 14,07 µm, sem diferenças significativas entre os tratamentos. Partículas obtidas pela atomização da emulsão apresentaram poros, todavia exibiram maior capacidade de carregamento do hidrolisado, cerca de 96%, enquanto as obtidas por dispersão apresentaram 54%. Variações durante o preparo da emulsão não proporcionaram alterações na morfologia e tamanho de partícula nas micropartículas, apesar de terem tido influência sobre as propriedades reológicas do sistema. A análise de difração de raios-X indicou que as micropartículas após 90 dias de preparo apresentaram a estrutura na forma polimórfica mais estável. A espectroscopia na região do infravermelho (FTIR) revelou que não ocorreu interação entre os ingredientes independentemente do modo de preparo das micropartículas. Tais resultados demonstram que a técnica de spray chilling é eficiente na microencapsulação de hidrolisado proteico de soja, possibilitando uma futura aplicação em alimentos. / Protein hydrolysates possess therapeutic properties and absorption easier than to proteins; however its application in food is limited due to its bitter taste, hygroscopic and reactivity. Encapsulation byspray chilling could be an alternative to minimize these limitations. This method consists in the atomization of a mixture formed by the dispersion or emulsion of the active material with the molten carrier, into an environment with temperature below the melting point of the carrier, under these conditions it solidifies to form spherical microparticles. The aim of this work was to develop microparticles loaded with hydrolyzed soy protein using the method of spray chilling and vegetable fat (PF 51°C) as carrier. Tests were conducted to obtain microparticles evaluating the feed by emulsion and dispersion and different formulations by varying the proportions active materials:carrier (1:5 and 1:10), homogenization speed by Ultra-Turrax (6000 and 8000 rpm) and temperature (60, 70 and 80°C ), totaling eighteen treatments. The mixtures were subjected to rheological analysis for determination of viscosity and after being atomized at spray chiller obtained microparticles were characterized by infrared spectroscopy and X-ray diffraction, particle size distribution and mean diameter measured using a laser light diffraction instrument and morphology was observed by scanning electron microscopy (SEM) and confocal microscopy. Solid lipid microparticles obtained were spherical and agglomerated the average size between 53.06 ± 2.17 µm and 68.03 ± 14.07 µm, there was no significant difference between formulations. Particles obtained by atomization of emulsion had presence of pores, but exhibited a higher loading capacity of the hydrolyzed, about 96%, while that obtained by dispersion had 54%. Changes during the preparation of the emulsion no provided changes at morphology and particle size of the microparticles, despite having influence on the rheological properties of the system. The analysis of X-ray diffraction showed that the microparticles after 90 days of storage had β polymorphic form. The infrared spectroscopy (FTIR) showed that there was no interaction between the ingredients regardless of the mode of preparation of the microparticles. These results demonstrate that the technique spray chilling is efficient in microencapsulation of soy protein hydrolyzate, allowing future use in foods.

The aim of this research was to develop a solid dosage form containing 1.5 g of the pesticide cypermethrin. The dosage should be stable in a tropical climate. In addition, it is to disintegrate and disperse in 10 L of tap water within 3 minutes. Such dissolution should yield a 150 ppm dispersion of cypermethrin, stable for at least one week. This provides for a dip dispersion to treat ticks and fly infestation on livestock. A new solid dosage was formulated as the scope of this research. It is a gel-based solid dosage form. Polymer electrolyte ASP4 - a copolymer of methacrylic acid, ethyl acrylate and diethyl maleate, was used to produce the gel. Preliminary tests revealed that ASP4- based gel, on its own, failed to meet the required dissolution time of 3 minutes. Strong entanglements of ASP4 chains impeded rapid dissolution. These strong entanglements occurred owing to the use of a high concentration of ASP4. Reducing the concentration of ASP4 yielded a solution of high viscosity instead of a gel. It was therefore decided to Gel-based solid dosage form for pesticide delivery use a superabsorbent (Product Z1069) in conjunction with ASP4 to produce the gel. Product Z1069 is a cross-linked sodium polyacrylate. Before producing the gel, a 1:1.5 by mass oil/water (O/W) emulsion was prepared using the phase-inversion route. The water (W) phase comprised 85.9% distilled water, 3.9% ASP4 at 20% dispersion, 8.6% sodium carbonate (0.5 M) and 1.6% Emulsogen EL. All concentrations are indicated in mass %. The oil (O) phase consisted of 76.9% cypermethrin, 19.3% Solvesso S200 and 3.8% Phenyl Sulphonate CA, also by mass. This emulsion was gelled by adding the superabsorbent Product Z1069 (ca. 37.5% by mass relative to the W phase of the emulsion). The superabsorbent strongly absorbed water, depleting it from the emulsion. This resulted in an increase of the effective concentration of ASP4 in the water phase of the emulsion. This increase of the polymer electrolyte concentration brought about a gel-like state corresponding to the desired solid dosage form. Rheometry confirmed that the dosage form maintained a solid gel-like consistency at 50°C. The dosage contained 24.6% m/m cypermethrin. Thus, the required dosage of 1.5 g was achieved in pellets weighing ca. 6.1 g. Such pellets rapidly disintegrated with mild stirring in 10 L of tap water. Complete pellet disintegration and active dispersion occurred within 2.5 minutes at ambient temperature (25 ± 2°C). / Dissertation (MSc)--University of Pretoria, 2008. / Chemistry / unrestricted

Sediments can act as both a sink for pollutants and a source for aquatic contaminants. Natural and human disturbances of the sediments can release the contaminants to the overlying water where bottom dwelling, or benthic, organisms may be exposed through direct contact, ingestion of sediment particles, or uptake of dissolved contaminants present in the water. Dredging, the most common remediation technology for heavy metals, exacerbates this process. The in situ use of emulsified metal has been studied for its ability to pull heavy metals from aqueous solution and from saturated soils. It has proven successful in the laboratory with removal of lead, cadmium, copper, nickel, and uranium from aqueous solution and removal of lead and cadmium from saturated spiked soils. The use of zero-valent metal particles, particularly those of zero-valent iron (Fe0), as an in situ remediation technique, is currently undergoing evaluation. The basic mechanism for removal appears to be reduction of contaminant metals followed by the subsequent precipitation of their insoluble forms. This is accompanied by the oxidation of the zero-valent metal. In the case of iron, Fe0 undergoes oxidation to Fe2+ and then to the Fe3+ state. Particulate Fe0 has been shown to precipitate Cr6+ to Cr3+ and Pb2+ undergoes reduction to Pb0. Initially, zero-valent iron filings were used to reduce the metal contaminants, but it has been shown that smaller size iron particles, such as nano-scale iron, have higher initial reduction rates as well as a higher concentration of contaminant removal per mole of iron. Emulsion liquid membrane (ELM) technology has been employed as a remediation technique for the removal of metals from wastewater where extraction and stripping processes are performed in a single operation. The ELMs are made by forming an emulsion between two immiscible liquids, such as oil and water, and are often stabilized by a surfactant. We have attempted to demonstrate the application of the combination of these two technologies through the use of emulsified zero-valent metal (EZVM) to treat sediments with heavy metal contamination. Emulsions were prepared using vegetable oil, water, Span 85, and either nanoscale Fe, 1-3 [micro]m Fe, 4 [micro]m Mg, or a 20 wt % Fe-Mg mixture. The results presented in this study demonstrate that EZVM is a viable technique for in situ remediation of heavy metals in sediments. Laboratory scale studies have shown high levels of removal of lead and cadmium from solution using emulsified zero-valent iron. Additionally, the use of emulsified magnesium has shown the ability for high levels of removal of copper, cadmium, nickel, lead, and uranium from solution. A variety of solution matrices were also explored for a lead solution including seawater, the presence of complexing agents and humic acids. Small-scale laboratory studies have shown 65% removal of lead and 45% removal of cadmium from saturated, spiked soils. A bench scale test to demonstrate the applicability of this technique in the environment revealed similar results for the removal of lead.

Asphalt tack coats are applied during pavement construction to ensure bond between pavement layers, thus providing a more durable pavement. A prototype tack coat evaluation device (TCED) was developed to evaluate the tensile and torque-shear strength of tack coat materials. Three emulsions (SS-1, CSS-1, and CRS-2) and one asphalt binder (PG 67-22), commonly used as tack coats, were evaluated using the TCED at various application temperatures, application rates, dilutions, and set times. A laboratory bond interface strength device (LBISD) was developed to assess interface shear strength of laboratory-prepared specimens. Mass loss testing was performed to evaluate moisture evaporation and visual breaking properties of emulsions. Study results indicate application rate, tack coat, and emulsion set time significantly affect TCED strength. Application rate also affected evaporation rate of emulsions.

No description available.

Acquired immune deficiency syndrome (AIDS) was first discovered in the 1980s, since then, human immunodeficiency virus (HIV) infection and AIDS have become global health, social, and economic concerns. HIV was identified as the cause of AIDS in 1985, and this launched a wide-reaching effort to understand its biology. The knowledge acquired from these vast research efforts contributed to the development of modern therapeutic and preventative treatment strategies. According to recent data from the United Nations Program on HIV/AIDS (UNAIDS), the ratio of infected people to AIDS- related deaths has decreased because of the expanding access to antiretroviral drugs (ARVs). The application of ARVs to HIV+ patients increases patients’ lifespans and improves the quality of life. Remaining as an incurable disease, expanding access to antiretroviral drugs and using prevention strategies are the best options to control the HIV pandemic for now. Treatment strategies with ARVs, however, are not sufficient to adequately address the HIV pandemic. Traditional combinational antiretroviral therapies (cART) for HIV treatment are limited by multiple drawbacks such as possible toxicity, limited drug concentrations, drug resistance, and viral rebound. Additionally, inadequate physicochemical properties of ARVs, such as poor solubility, permeability, and bioavailability, lead to limited absorption and biodistribution, resulting in poor clinical outcomes. Patient compliance and suboptimal efficacy lead to the development of resistant viruses and viral reservoirs. The presence of HIV reservoirs would cause viral rebound two to four weeks after terminating treatments. The complexity of reservoir structure, prolonged cell half-life, and the latent HIV viruses complicate HIV treatments iii targeting viral reservoirs. cART exhibits insufficient efficacy towards reservoir sites because of biological barriers and poor physicochemical properties. These problems highlight an urgent need for novel treatment strategies that are safe and effective to address HIV reservoirs. Innovative and improved delivery systems have been proposed over the years, especially lipid-formulations. Lipid formulations have emerged as promising vehicles owing to their ability to encapsulate molecules with poor solubility and bioavailability, improve active targeting, prolong circulation time, and sustain drug release. Cell-mediated delivery strategy have posed the obstacles of insufficient drug transport and safety. Macrophages, the very same cells that carry the HIV virus, could reach tissues that would otherwise have little or no drug penetration. Macrophages can protect drugs from metabolic degradation with large quantities of drugs for delivery. Activated macrophages express the folate receptor, a potential targeting moiety. In this study, I intended to develop a novel folate-decorated nanoemulsion (FA- NE) for the delivery of ARVs to HIV infected macrophages. To reach the goal, I focused on two goals: (1) construction of a nanocarrier capable of encapsulating ARV drugs with physiological properties suitable for use in drug delivery and (2) enhancement of delivery to HIV infected macrophages. In Chapter 2, I discuss the rationale for nanoART for HIV treatments. I introduce current HIV treatments and their drawbacks, notably the viral rebound due to limited drug concentration in viral reservoirs. Then I explain why nanotechnology would be a promising strategy for HIV treatment and provide examples of nanomedicine. In all iv cases, however, cell uptake and drug release were limited or complicated by toxicity, which is a significant issue for a validated delivery system that are safe and effective. In chapter 3, I introduce the design and development of the FA-NE. This system includes (1) an oil core to encapsulate antiretroviral drugs that are highly hydrophobic, (2) a lipid monolayer to protect the oil core and to form nanoemulsion (3) folate for target. The system was prepared using the emulsification solvent evaporation method, developed and optimized based on physical properties, including size, PDI, zeta potential, and other in vitro characterizations, such as encapsulation efficacy, drug loading, stability, and drug release. Chapter 4 is a continuation of the work done in Chapter 3 and focuses on the enhancement of cellular uptake with folate overexpression cell models. A lipopolysaccharide (LPS) activated macrophages was built and utilized for intracellular drug release and retention evaluations. In Chapter 5, cytotoxicity and antiretroviral efficacy studies are described. With the conclusion drawn in Chapter 4, I was curious if the enhanced cellular uptake can be translated into improved efficacy. As a result, collaborated with Dr. Kamel Khalili, School of Medicine, Temple University, we evaluated antiretroviral efficacy with an HIV indicator cell and monocyte-derived-macrophages from human donors. Furthermore, I performed cytotoxicity assay to evaluate this nanoemulsion system safety profile. Chapter 6 summarizes the highlights and conclusions of this project and provides suggestions for the future. / Pharmaceutical Sciences