Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 30-32). Also available on the World Wide Web.

Thesis (M.Sc. (Pharmacy)) - Rhodes University, 2007.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains viii, 59 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 54-56).

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Marc Smith, Committee Member ; P.K. Yeung, Committee Member ; Benjamin Shapiro, Committee Member ; Sheldon Jeter, Committee Member ; Yogendra Joshi, Committee Chair.

Dissertation presented in partial compliance with the requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology, 2009. / This study was mainly a response to a challenge faced by ESKOM in its coal-fired power stations. In spite of using high purity water to drive the turbines, the latter were damaged by ‘pitting’, possibly related to acids generated at high temperatures. In the light of this a relatively simple method for determination of short chain organic acids was identified by comparing the efficacies of several methods. It was found that high performance liquid chromatography (HPLC) method preceded by derivatization (with o-nitrophenyl hydrazine) is suitable for analyzing mixtures of simple acids at ppb levels. Calibration was effected by using methanoic acid (formic acid), ethanoic acid (acetic acid), propanoic acid (propionic acid) and butanoic acid (butyric acid). The HPLC instrument used was from Thermo Separations with P2000 pump, SN 4000 interface and UV1000 with a column heater. A comparative study between the HPLC methods using ion exclusion and partition chromatography was carried out in order to find a suitable method that can be used with aqueous environmental samples. The two essential columns that were used were ion exclusion Phenomenex Rezex OA column and a Nucleodur C8 column. The method of partition chromatography using a C8 column showed the most success using a mobile phase consisted of acidified water using HCl (pH4.5) along with a 60:40 Acetonitrile/Methanol mixture. Both isocratic and gradient programs were utilized. Limits of detection were improved from 800ppb (formic acid), 480ppb (acetic), 350ppb (propionic) and 680ppb (butyric acid) to 25ppb (acetic), 60ppb (propionic) and 90ppb (butyric). Samples used in analysis were collected from the main stream, economiser, condensers, polishing plant and turbines of the Tutuka Power Station in Mpumalanga province and analysed using with final developed method / Eskom Tertiary Support Programme. Durban University of Technology

Des industriels du domaine aéronautique se sont regroupés autour du projet MEKINOX (Mécanique Inoxydable) visant à développer l'utilisation de différentes nuances d'aciers inoxydables en raison de leur haute résistance mécanique et de leur résistance à la corrosion. Cependant ces aciers sont réputés sensibles au frottement. Dans ce contexte, ce travail de thèse est dédié dans un premier temps à l'étude de l'effet des différents traitements thermiques et de surface sur la microstructure des aciers inoxydables visant à améliorer leur aptitude au frottement. Nous avons mis en évidence différents mécanismes de durcissement : par précipitation, par changement de phase et par solution solide. Dans un deuxième temps, nous avons mis en place une démarche expérimentale permettant de comparer la réponse des différents couples de matériaux sous contact roulant et glissant extrêmes. Ces essais nous ont permis de caractériser l'évolution du coefficient de traction et de classer les différents états métallurgiques selon leur résistance à l'usure. Dans un troisième temps, nous avons caractérisé les différents types d'endommagements se produisant en surface et en sous-couche. Enfin, l'utilisation de l'EBSD nous a permis caractériser la déformation plastique en sous couche et de tenter de corréler la valeur de la densité de HAGB (Angles à forte désorientation) avec la résistance à l'usure des différents états métallurgiques des aciers étudiés. / Aeronautics industrials gathered thought MEKINOX project ("Mécanique Inoxydable") in order to develop the use of different stainless steels grades, because both their high strength and corrosion resistance. However, these steels are deemed sensitive to friction. In this context, this thesis is dedicated firstly to study the effect of different thermal and surface treatments on the microstructure of stainless steels to improve their ability to friction. Different hardening mechanisms were observed: precipitation, phase change and solid solution. Secondly, we have implemented an experimental approach for comparing the response of the various materials pairs under extreme sliding and rolling contact. These tests have allowed us to characterize the friction coefficient evolution and classify the different metallurgical materials and treatments according to their wear resistance. Thirdly we have characterized the different types of damage occurring at surface and in the subsurface. Finally, the use of EBSD allowed us to characterize the plastic deformation in the subsurface and to correlate the value HAGB (High Angle Grains Boundaries) density with the wear resistance of the different metallurgical materials and treatments of the examined steels.

Shrinking down into nanoscale, materials exhibit huge property advantages over their bulk form. New forms of carbon at nanoscale have occupied the prominent position in modern materials research. With a very long history accompanying our human civilisation, carbon as a wonder material has once again contributed to our technological advances, as evidenced by the discoveries and research attractions in the last a few decades. Research into fullerenes (C60, C70, etc.), carbon nanotubes (CNTs) and graphene has been continued raising, because of the numerous novel properties associated with these new carbon forms1-3. On top of their excellent electronical, physical and chemical properties, CNTs and graphene also exhibit excellent mechanical properties including ultra-high tensile strength, Young’s Modulus, as well as high thermal conductivities. Research into carbon has also promoted the flourish of many new non-carbon nanomaterials, and typical examples include the inorganic fullerene-like tungsten disulphide (IF-WS2) nanoparticles (NPs), numerous oxide NPs and nanowires that also exhibit various remarkable properties, such as high hardness and anti-oxidation stability. To combine the outstanding performances of both carbon and non-carbon nanomaterials by marrying nanoscale carbon with various metal oxide particles, which forms the backbone of my thesis by carrying out the intensive investigations. In my project it have further validated the advantages of the resulting new carbon-coated NPs in different polymeric matrix composites. The main findings are as follows: 1. A home-made rotary chemical vapour deposit (RCVD) system has been modified and this versatile facility has been applied successfully to produce different types of graphitic carbon-coated nanocomposite particles, from micro- down to nano-scale, including IF-WS2, TiO2, ZnO, Y2O3, Cr2O3, CeO2 and ZrO2 etc. The production can be up to 30 g/per batch, which is 10s times more than using a traditional static furnace, by avoiding severe agglomeration. 2. The resulting coating consists of a few layered graphitic carbon with lattice space 0.34 nm. The thickness of the coating is simply controllable between 1-5 nm, depending on the deposition time (10~60 min), precursor injection flow rate (1.2~2.4 ml/L) and heating temperature (700~900 oC). Furthermore, the oxide core of ZnO@C was removed by heating under the H2/Ar atmosphere, and have successfully generated nano- to micro-scale, hollow, closed, and all-carbon structures. 3. The commercial Nylon 12 is applied to fabricate the metal oxide polymer composite. Using ZnO@C-Nylon 12 composite as an example, at 2 wt% content, the composites have achieved with the ultimate tensile strength increased by 27% (from 47.9 to 59.6 MPa), In particular, at 4 wt% content, the ZnO@C showed an impressive improvement in thermal conductivity of nearly 50% (From 0.21 t0 0.31 W∙m-1∙K-1), comparing 16% improvement for ZnO-Nylon 12 composite. 4. Apart from investigations of nylon composite, intensive studies of the Poly ether ether ketone (PEEK), an important high performance engineering thermoplastics polymer, and its nanocomposites reinforced by IF-WS2 and IF-WS2@C have been carried out in this thesis. The IF-WS2/PEEK composites exhibited not only an improvements of 24% (From 77.6 to 96.7 MPa) in the tensile strength (2 wt%), but also showed an extraordinary increase in thermal conductivity by 190%, from 0.248 to 0.719 W∙m-1∙K-1 at 8 wt%, higher onset decomposing temperatures (54 oC) against the plain PEEK. 5. Moreover, owing to the better dispersal capacity of IF-WS2@C NPs, the ternary IF-WS2@C-PEEK nanocomposites produced in this thesis displayed impressive mechanical properties, increased by 51% (From 77.6 to 120.9 MPa, at 2 wt%), and extremely greater thermal conductivity, with 235% (From 0.248 to 0.831 W∙m-1∙K-1 at 8 wt%), and better stability than the comparison IF-WS2-PEEK composites. The parameters influencing the coating quality and thickness have also been investigated. Further, their interface studies based on the FTIR and XPS techniques have verified the formation of chemical bonding (C=S bonding and carbon π-π bonding), rather than physically bonded together. The successful application of the generic RCVD process can be further extended to the processing of many new particles for an ultrathin carbon coating. Considering the vast amount of literature focusing on carbon, the project further processing of carbon-coated materials in composites could easily be tailored to achieve desired surface contacts with different matrices and leading to the better desired performance, as verified in this thesis for the advanced binary and ternary composites. Finally, this research is expecting to expand the application potentials of PEEK-based nanocomposites in critical areas where thermal conductivity and thermal stability are important.

Throughout Europe, the introduction of Solvency II is forcing companies in the life assurance and pensions provision markets to change how they estimate their liabilities. Historically, each solvency assessment required that the estimation of liabilities was performed once, using actuaries' views of economic and demographic trends. Solvency II requires that each assessment of solvency implies a 1-in-200 chance of not being able to meet the liabilities. The underlying stochastic nature of these requirements has introduced significant challenges if the required calculations are to be performed correctly, without resorting to excessive approximations, within practical timescales. Currently, practitioners within UK pension provision companies consider the calculations required to meet new regulations to be outside the realms of anything which is achievable. This project brings the calculations within reach: this thesis shows that it is possible to perform the required calculations in manageable time scales, using entirely reasonable quantities of hardware. This is achieved through the use of several techniques: firstly, a new algorithm has been developed which reduces the computational complexity of the reserving algorithm from O(T2) to O(T) for T projection steps, and is sufficiently general to be applicable to a wide range of non unit-linked policies; secondly, efficient ab-initio code, which may be tuned to optimise its performance on many current architectures, has been written; thirdly, approximations which do not change the result by a significant amount have been introduced; and, finally, high performance computers have been used to run the code. This project demonstrates that the calculations can be completed in under three minutes when using 12,000 cores of a supercomputer, or in under eight hours when using 80 cores of a moderately sized cluster.

Mephenoxalone is a mild central nervous system depressant with activity resembling that of meprobamate. Since its introduction in 1961 mephenoxalone has been used as an anxiolytic and as a muscle relaxant, although the latter effect is weak. Preliminary studies on the absorption and disposition of mephenoxalone have been conducted in beagle dogs but no pharmacokinetic data from human studies have been reported, except for a single study in which the biotransformation products present in human urine were identified. Methods presently available for the determination of mephenoxalone in biological fluids lack the sensitivity, specificity and precision required for detailed pharmacokinetic studies. In this study, a rapid, sensitive, precise reverse-phase high-performance liquid chromatographic method with ultraviolet detection at 200nm was employed for the determination of mephenoxalone in biological fluids. Serum and urine samples were prepared for chromatographic analysis using simple liquid-liquid extraction techniques. The application of the assay to pharmacokinetic studies in humans is presented. After administration of a single oral dose of 400mg mephenoxalone dispersed in 150ml water to six young, healthy volunteers, the compound was rapidly absorbed with the peak concentration of 8μg/ml occurring after about 1 hour. The elimination half-life was approximately 3 hours. The drug was extensively metabolized with only about 1 percent of the administered dose being excreted unchanged in the urine after 24 hours. The bioavailability of a newly developed mephenoxalone-containing tablet was also investigated. The drug was absorbed more rapidly from the tablet than from the dispersed dose. This was attributed to a shorter in vivo dissolution time on the basis of in vitro tests, but this effect is not expected to be clinically significant. In addition, two human urinary metabolites of mephenoxalone were identified as unconjugated hydroxylated derivatives using thermospray HPLC-mass spectrometry. The plasma protein-binding properties of mephenoxalone were also investigated.

Erythromycin, a macrolide antibiotic used mainly against gram-positive bacteria has been in clinical use since 1952 (1). Previous pharmacokinetic data published on this antibiotic have been derived predominantly from microbiological assay techniques. However, these techniques are relatively imprecise as well as being non-specific and extremely tedious to perform. A novel high performance liquid chromatographic analysis of erythromycin in human serum and urine using U.V. detection at 200 nm and/or electrochemical detection using both an amperometric and a coulometric electrochemical detector is presented. The method involves a solid phase extraction procedure followed by a simple phase separation step and chromatography on a reverse phase column. In order to select the optimum U.V. detector for this analysis, five "state of the art" detectors were compared in terms of their signal-to-noise ratios at U.V. wavelengths between 200 and 210 nm. A known metabolite des-N-methylerythromycin is readily detectable using U.V. detection, whilst another metabolite/degradation product anhydroerythromycin is not seen using U.V. detection but is readily observable using an electrochemical detector. The method has a limit of sensitivity of 0.25 μg/mL and 1.00 μg/mL in serum and urine respectively (U.V. detection) and is sufficiently sensitive to monitor serum and urine concentrations of erythromycin in man after administration of a single 500 mg erythromycin stearate tablet. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in