Precipitation with a Compressed Fluid Antisolvent (PCA) and Rapid Expansion from Supercritical Solution (RESS) are two processes based on supercritical fluids that are capable of producing submicron particles. Novel variations of these basic processes have been examined to produce stable particles of various pharmaceutical compounds. PCA is an antisolvent precipitation technique where an organic solution of drug + polymer in solvent is atomized (sprayed) into supercritical (SC) CO₂. Upon liquid mixing, the solute materials precipitate to form microparticles. A Vapor-over-Liquid technique has been used to produce larger, uniform particle sizes of biodegradable polymers. By suspending a protein in the solvent phase, the protein can be encapsulated/coated by the precipitating polymer. RESS is a process by which a homogeneous solution at supercritical conditions is sprayed through an expansion nozzle to atmospheric conditions. The resultant change in phase leads to the precipitation of the solute materials. The production of extremely small particles (<50 nm) have been predicted but rarely demonstrated. Typically, particle growth occurs to form larger (~1 μm) particles. A novel adaptation was developed, dubbed RESAS (Rapid Expansion from Supercritical to Aqueous Solution), wherein the expansion is conducted within an aqueous environment. The aqueous phase can contain surfactant or lipid stabilizers to capture and preserve submicron particles of water-insoluble drug actives in the form of a suspension. / text

Amine degradation in aqueous amine scrubbing systems for capturing CO₂ from coal fired power plants is a major problem. Oxygen in the flue gas is the major cause of solvent deterioration, which increases the cost of CO₂ capture due to reduced capacity, reduced rates, increased corrosion, solvent makeup, foaming, and reclaiming. Degradation also produces environmentally hazardous materials: ammonia, amides, aldehydes, nitramines, and nitrosamines. Thus it is important to understand and mitigate amine oxidation in industrial CO₂ capture systems. A series of lab-scale experiments was conducted to better understand the causes of and solutions to amine oxidation. This work included determination of rates, products, catalysts, and inhibitors for various amines at various conditions. Special attention was paid to understanding monoethanolamine (MEA) oxidation, whereas oxidation of piperazine (PZ) and other amines was less thorough. The most important scientific contribution of this work has been to show that amine oxidation in real CO₂ capture systems is much more complex than previously believed, and cannot be explained by mass transfer or reaction kinetics in the absorber by itself, or by dissolved oxygen kinetics in the cross exchanger. An accurate representation of MEA oxidation in real systems must take into account catalysts present (especially Mn and Fe), enhanced oxygen mass transfer in the absorber as a function of various process conditions, and possibly oxygen carriers other than dissolved oxygen in the cross exchanger and stripper. Strategies for mitigating oxidative degradation at low temperature, proposed in this and previous work are less effective or ineffective with high temperature cycling, which is more representative of real systems. In order of effectiveness, these strategies are: selecting an amine resistant to oxidation, reduction of dissolved metals in the system, reduction of the stripper temperature, reduction of the absorber temperature, and addition of a chemical inhibitor to the system. Intercooling in the absorber can reduce amine oxidation and improve energy efficiency, whereas amine oxidation should be considered in choosing the optimal stripper temperature. In real systems, 2-amino-2-methyl-1-propanol (AMP) is expected to be the most resistant to oxidation, followed by PZ and PZ derivatives, then methyldiethanolamine (MDEA), and then MEA. MEA oxidation with high temperature cycling is increased 70% by raising the cycling temperature from 100 to 120 °C, the proposed operational temperature range of the stripper. PZ oxidation is increased 100% by cycling to 150 °C as opposed to 120 °C. Metals are expected to increase oxidation in MEA and PZ with high temperature cycling by 40 - 80%. Inhibitor A is not expected to be effective in real systems with MEA or with PZ. MDEA is also not effective as an inhibitor in MEA, and chelating agents diethylenetriamine penta (acetic acid) (DTPA) and 2,5-dimercapto-1,3,4-thiadiazole (DMcT) are only mildly effective in MEA. Although MEA oxidation in real systems cannot be significantly reduced by any known additives, it can be accurately monitored on a continuous basis by measuring ammonia production from the absorber. Ammonia production was shown to account for two-thirds of nitrogen in degraded MEA at low temperature and with high temperature cycling, suggesting that it is a reliable indicator of MEA oxidation under a variety of process conditions. A proposed system, which minimizes amine oxidation while maintaining excellent rate and thermodynamic properties for CO₂ capture would involve use of 4 m AMP + 2 m PZ as a capture solvent with the stripper at 135 °C, intercooling in the absorber, and use of a corrosion inhibitor or continuous metals removal system. Reducing (anaerobic) conditions should be avoided to prevent excessive corrosion from occurring and minimize the amount of dissolved metals. This system is expected to reduce amine oxidation by 90-95% compared with the base case 7 m MEA with the stripper at 120 °C. / text

D. Tech. Chemistry. / Demonstrates the possibility of preparing large surface coatings of monodispersed spherical particles of chromium(III) oxide by using the ACG method for solar heating and magneto-optic technologies. t is aimed in the current study to investigate the photo-induced ESR phenomena in a-Cr2O3 mono-dispersed spherical particles using elimination of 160mW Nd:YAG laser of ˜1064 nm and a pulse repetition frequency of 30Hz, in the temperature range of 150 up to 315 K.

Contaminated sites are found all around the world. In order to contain these contaminants, engineers propose capping the contaminated sediments with a sand cap. When capping these contaminants, the sand causes consolidation to occur and could cause a slope failure if the contaminants were on a slope. Investigating the properties of these contaminated sediments allows for proper analysis of a slope failure. The primary objective of this research was to determine the shear strength of contaminated sediments. Since soil samples from actual contaminated sites are highly variable and difficult to explain, the soil used in this research project was mixed and controlled in the lab. A mixture of Kaolinite, water and mineral oil (NAPL, non-aqueous phase liquid) was used for the specimens. Different oil amounts were placed into the specimens to create different scenarios. The different oil combinations included: 100% water, 100% oil, 90% oil, 70% oil, and 50% oil. All of the specimens were fully saturated, and the specimens that had less than 100% oil contained water in the remaining percentage. Consolidated Undrained and Consolidated Drained triaxial tests were performed on the specimens. The constructed specimens were subjected to consolidation stages ranging from 0.6psi to 29psi in confining pressure. The main focus of the study was on low confining pressures. After consolidation the specimens were sheared either undrained or drained. Both tests were utilized in order to see the difference in the pore pressures generated. Failure envelopes were developed for the different oil contents that contained three dimensions included the shear strength, the effective stress, and the pore pressure difference between the pore oil pressures and the pore water pressures. Also, the behavior of oil-dominated versus water-dominated was determined. Results from the 100% water specimens were comparable to previous data. The shear strength for the 100% oil specimens was higher than the 100% water specimens, but lower than the 90% oil and 70% oil specimens. The 50% oil specimens resulted in a great deal of variability on whether the specimen was water-dominated or oil-dominated. The main conclusion was that the Kaolinite had an increase in strength with the introduction of mineral oil. / text

Arsenic-based pesticide residues have been detected on Arizona State Museum’s (ASM) Diné (Navajo) textile collection using a handheld portable X-ray (pXRF) spectrometer. The removal of this toxic pesticide from historic textiles in museums and collections is necessary to reduce potential health risks to Native American communities, museum professionals, and visitors to these cultural institutions. A leader in engineering innovative pesticide removal methods, ASM received federal funding support to continue essential research in removing heavy metal pesticides from cultural property. The research objective was divided into three interconnected stages: (1) calibrate the pXRF instrument for arsenic contaminated cotton and wool textiles; (2) engineer a textile conservation aqueous washing treatment to remove arsenic from wool textiles; (3) demonstrate the aqueous washing treatment method on actual Navajo textiles known to have arsenic-based pesticide residues. The calibration process consisted of a dipping method to produce known homogenous arsenic cotton and wool test samples saturated with solutions of 100, 500, 1000, 2500, and 5000 parts per million (ppm). A linear correlation between observed pXRF test readings and formulated arsenic solutions corroborated the instruments range of detection for arsenic on specific textile materials. The calibration confirms that the pXRF is suitable instrument to measure the removal of arsenic from wool textiles. Wool test samples treated with solutions of an arsenic concentration of 1000ppm were used to develop an optimal aqueous washing treatment exploring the effects of time, temperature, agitation, and pH conditions to efficiently remove arsenic while minimizing damage to the structure and properties of the textile. Each conditional effect removed a certain percentage of arsenic, although the most efficient aqueous washing treatment consisted of submerging a wool textile in deionized water at room temperature for ten minutes with the greatest level of agitation within reason to minimize damage the textile. The final stage of the research applied the aqueous washing guidelines formulated from experimental research on three historic ASM Navajo textiles. Two textiles contained low arsenic concentrations (<100ppm), and one tested with a high arsenic concentration (~1000ppm). The aqueous washing treatment resulted in minimal change for low arsenic concentration textiles, and a 96% removal of arsenic on a high arsenic concentration textile. The preliminary success of removing arsenic-based pesticide residues from historic Navajo textiles greatly impacts the future management of historic textile collections, and also raises questions to further refine the research methodology or pursue alternative related research such as engineering a closed circulating arsenic removal system to limit the quantity of toxic water.

Percutaneous delivery of drugs promises many advantages over oral or intravenous administration, such as a better control of blood levels, a reduced incidence of systemic toxicity, an absence of hepatic first-pass metabolism, better patient compliance, etc. However, the dermal drug transport is limited by the unsuitable physicochemical properties of most drugs and the efficient barrier function of the skin. Thus, numerous attempts have been reported to improve topical absorption of drugs, concentrating mainly on the barrier function of the stratum corneum by use of penetration enhancers and/or skin warming. An alternative and interesting possibility for improved dermal permeability is the synthesis of derivatives or analogues with the aim of changing the physicochemical properties in favour of skin permeation, efficacy and therapeutic value. Cyclizine (I) is an anti-emetic drug primarily indicated for the prophylaxis and treatment of nausea and vomiting associated with motion sickness, post operation and Meniere's disease. It acts both on the emetic trigger zone and by damping the labyrinthine sensitivity. Pharmacologically it has anti-histaminic, antiserotonergic, local anaesthetic and vagolytic actions. It is widely used and also suitable for children from six year of age. Percutaneous absorption of (I) can, among others, avoid the "first-pass" effect and the discomfort of injection. The main objective of this study was to explore the feasibility of percutaneous absorption of (I) and its alkyl analogues via physicochemical characterization and assessment of their permeation parameters. The intent was also to establish a correlation between the physicochemical properties of these compounds and their percutaneous rate of absorption. To achieve these objectives, the study was undertaken by synthesizing the alkyl analogues and determining the physicochemical parameters relevant to skin transport. Identification and level of purity for the prepared analogues were confirmed by mass spectrometry (MS), nuclear magnetic resonance (NMR) spectrometry and infrared (IR) spectrometry. Experimental aqueous solubility (25 °c & 32 °C) and partition coefficient for each compound were determined. In vitro permeation studies were performed at pH 7.4, using Franz diffusion cells with human epidermal membranes. Diffusion experiments were conducted over a period of 24 hours maintaining a constant temperature (37 DC) by means of water bath. All samples were analysed by high pressure liquid chromatography (HPLC). Cyclizine (I) has a methyl group at N-4. Increasing the alkyl chain length on N-4 of the piperazine ring resulted' in compounds with lower melting points and higher water solubility than (I). (II) exhibited 3-fold increase in water solubility, followed by (IV) with about 2.5 fold increase. The water solubility of (III) was almost the same as that of (I). Log partition coefficients increased linearly with increasing alkyl chain length. The analogues therefore, possessed more favourable physicochemical properties to be delivered percutaneously. Indeed, the in vitro skin permeation data proved that these analogues could be delivered more easily than (I) itself. The flux of (I) was 0.132 ug/cm2/h in a saturated aqueous solution. Compound (II) resulted in a 53-fold (6.952 ug/cm2/h) increase in permeation compared to (I). (III) and (IV) resulted in a 2- and 5fold enhancement of permeation respectively. Based on the results of the study, it seems that increased aqueous solubility and low level of crystallinity play a vital role in optimizing percutaneous absorption of (I) and its alkyl analogues. But the importance of the effect of increased lipophilicity cannot be ignored. The low percutaneous• absorption of (I) might be attributed to its low aqueous solubility and increased crystallinity, as is evident from the higher melting point than the analogues. From all the permeability data using aqueous solutions, it is clear that compound (II) is the best permeant of this series and in addition it is known that this compound antagonizes the effects of histamine. / Thesis (M.Sc. (Pharm.))--North-West University, Potchefstroom Campus, 2004.

Degassing and in situ formation of a mobile gas phase takes place when an aqueous phase equilibrated with a gas at a pressure higher than the subsurface pressure is injected in water-saturated porous media. This process, which has been termed supersaturated water injection (SWI), is a novel and hitherto unexplored means of introducing a gas phase into the subsurface. Herein is a first macroscopic account of the SWI process on the basis of continuum scale simulations and column experiments with CO2 as the dissolved gas. A published empirical mass transfer correlation (Nambi and Powers, Water Resour Res, 2003) is found to adequately describe the non-equilibrium transfer of CO2 between the aqueous and gas phases. Remarkably, the dynamics of gas-water two-phase flow, observed in a series of SWI experiments in homogeneous columns packed with silica sand or glass beads, are accurately predicted by traditional two-phase flow theory which allows the corresponding gas phase relative permeability to be determined. A key consequence of the finding, that the displacement of the aqueous phase by gas is compact at the macroscopic scale, is consistent with pore scale simulations of repeated mobilization, fragmentation and coalescence of large gas clusters (i.e., large ganglion dynamics) driven entirely by mass transfer. The significance of this finding for the efficient delivery of a gas phase below the water table in relation to the alternative process of in-situ air sparging and the potential advantages of SWI are discussed. SWI has been shown to mobilize a previously immobile oil phase in the subsurface of 3-phase systems (oil, water and gas). A macroscopic account of the SWI process is given on the basis of continuum-scale simulations and column experiments using CO2 as the dissolved gas and kerosene as the trapped oil phase. Experimental observations show that the presence of oil ganglia in the subsurface alters gas phase mobility from 2-phase predictions. A corresponding 3-phase gas relative permeability function is determined, whereas a published 3-phase relative permeability correlation (Stone, Journal of Cana Petro Tech, 1973) is found to be inadequate for describing oil phase flow during SWI. A function to predict oil phase relative permeability is developed for use during SWI at high aqueous phase saturations with a disconnected oil phase and quasi-disconnected gas phase. Remarkably, the dynamics of gas-water-oil 3-phase flow, observed in a series of SWI experiments in homogeneous columns packed with silica sand or glass beads, are accurately predicted by traditional continuum-scale flow theory. The developed relative permeability function is compared to Stone’s Method and shown to approximate it in all regions while accurately describing oil flow during SWI. A published validation of Stone’s Method (Fayers and Matthews, Soc of Petro Eng Journal, 1984) is cited to validate this approximation of Stone’s Method.

Project I: [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 as a Homogeneous Hydrogenation Catalyst for Biomass Derived Substrates. The complex [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 has been shown to be an active ionic hydrogenation catalyst for selected carbonyls, diols and glycerol by the Schlaf group. It was postulated to also be active for other biomass derived substrates such as levulinic acid (LA), furfural and 5-hydroxymethyl furfural (HMF). Synthesis of the complex was optimized and full characterization carried out by 1H/13C –NMR. The complex was tested against LA in aqueous sulfolane medium and the furfural/HMF model system 2,5-hexanedione in water. Activity of the complex was compared to the analogous metal-ligand bifunctional (MLB) system described in Project II. The complex exhibited good thermal stability up to 200 oC in 90/10 wt% sulfolane/water mixtures and was capable of hydrogenation of LA to γ-valerolactone in 95% yield. Addition of protic acids to the reaction mixture and increasing proportions of water decreased the activity of the complex towards the hydrogenation of LA. Project II: [Ru(OH2)3(di(picolyl)amine)](OTf)2 as an acid-, water- stable, metal-ligand bifunctional deoxygenation catalyst. The complex [Ru(OH2)3(di(picolyl)amine)](OTf)2 was postulated to be an active MLB ionic hydrogenation catalyst under acidic aqueous conditions. Using the substantially labile [Ru(DMF)6](OTF)3 ruthenium complex as the precursor, the desired complex was prepared insitu by coordination of the DPA ligand and concomitant reduction of Ru3+ to Ru2+. The complex was characterized by 1H/13C-NMR and tested for the hydrogenation of LA, 2,5-hexanedione, furfural and HMF under acidic aqueous conditions. The complex exhibited thermal stability up to 150 oC and was active for the hydrogenation of carbonyls, as demonstrated by the conversion of 2,5-hexanedione to 2,5-hexanediol in 94% yield in water. Addition of H3PO4 as an acid cocatalyst resulted in nearly complete conversion to dimethyltetrahydrofuran (DMTHF) but further deoxygenation could not be achieved. Direct comparision of [Ru(OH2)3(di(picolyl)amine)](OTf)2 and [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 under identical conditions against LA and 2,5-hexanedione demonstrated that the[Ru(OH2)3(di(picolyl)amine)](OTf)2 catalyst is more active than the [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 complex in all cases, suggesting that the di(picolyl)amine complex operates through a MLB ionic hydrogenation mechanism. / NSERC

Functional water-soluble polymers find applications in a variety of fields including waste-water treatment, pharmaceuticals, cosmetics, drug delivery, and hygiene. Despite the increased demand for these products, understanding of their synthesis by free-radical aqueous-phase polymerization has lagged behind that of polymers produced in organic solvents. In this doctoral work, the free-radical batch and semibatch aqueous-phase polymerization of N-vinylpyrrolidone (NVP), N-vinylformamide (NVF), N-vinylimidazole (NVI) and quaternized vinylimidazole (QVI), as well as NVP polymerized in n-butanol, has been studied. Kinetic models are developed to describe monomer conversion and polymer molecular weight (MW) behaviour of these systems. The expressions developed from independent pulsed-laser studies for propagation (kp) and termination (kt) rate coefficients, including their variation with monomer concentration and conversion, are shown to provide an excellent description of aqueous-phase NVP polymerization. Polymerization of NVP in butanol and of NVF in water are well-represented by the base NVP model, with differences in polymerization rate and polymer MWs simply accounted for by the differences in kp for the systems, indicating that the kt behaviour must be quite similar. The NVI/QVI study demonstrates the importance of a pH-dependent degradative addition reaction to monomer for NVI, with polymerization behaviour identical to that of QVI for pH 1, an effect captured in the model developed to describe the system. The aqueous-phase copolymerization of NVP and NVF was also studied, and reactivity ratios were determined to be very close to unity. This information was combined with the kp and kt expressions used to describe NVP and NVF homopolymerizations, with no other additional parameters required to model the copolymerization rate, copolymer composition and copolymer MW. This result demonstrates that the improved homopolymerization knowledge of these water-soluble monomers can be easily extended to understand their behaviour in copolymerization. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2011-12-21 16:05:14.904

A procedure for the preparation of spinach leaf mitochondria was developed. The procedure combines differential centrifugation, partition in dextran- polyethyleneglycol two-phase system and Percoli density gradient centri- fugation. The different steps separate the material mainly according to size, surface properties and density, respectively. No chlorophyll was present in the final mitochondrial preparation and the mitochondria were also markedly enriched relative to peroxisomes and microsomes as esti­mated from the recovery of marker enzymes. The latency of enzyme activities was used to study the apparent intactness of the mitochondrial membranes. These measurements showed that both the inner and outer mitochondrial membranes were more than 90 % intact. The mitochondria were also functionally intact since the coupling between respiration and oxidative phosphorylation was retained. The purity of the preparation made it possible to study cytochromes from leaf mitochondria. The cytochrome content of stalk and leaf mitochondria was measured in order to compare mitochondria from photosynthesizing and non-photosynthesizing tissue. The measurements were performed by difference spectroscopy both at room temperature and at liquid nitrogen temperature. Qualitatively the cytochrome content in mitochondria from stalks and leaves was identical. Quantiatively leaf mitochondria contained,on a protein basis, only half the amount of the different cytochromes as compared to stalk mitochondria. The relative content of the different cytochromes was, however, similar suggesting that the composition of the respiratory chain was the same. The photorespiratory conversion of glycine to serine takes place in the mitochondria and involves oxidative decarboxylation of glycine. The ability to oxidize glycine via the respiratory chain was present in spinach leaf mitochondria, but absent in mitochondria prepared from roots, stalks and leaf veins from the same plants. This confirmed the specific localization of the glycine oxidizing activity to photosyntheticaliy active tissue, as suggested by studies with other plant material. The conversion of glycine to serine is a complex reaction depending on the combined action of two enzymes: glycine decarboxylase and serine hydroxymethyltransferase. The effect of inhibitors on the serine hydroxy­methyl transferase activity and the rate of the glycine bicarbonate exchange reaction associated with glycine decarboxylase was studied. These reactions represent partial steps in the conversion of glycine to serine and the aim was to investigate the site of inhibition for the different inhibitors, namely, isonicotinyl hydrazide (a pyridoxa!phosphate antagonist), amino- acetonitrile, glycinehydroxamate (glycine analogues) and cyanide. The results showed that these inhibitors had a complex pattern of inhibition. The same inhibitor affected more than one site and often with an apparently different mechanism. It was, however, found that aminoacetonitrile at low concentrations specifically inhibited glycine decarboxylase and that cyanide specifically inhibited serine hydroxymethyltransferase. / digitalisering@umu