Yes / In this study, a comparison of different methods to predict drug−polymer solubility was carried out on binary systems consisting of five model drugs (paracetamol, chloramphenicol, celecoxib, indomethacin, and felodipine) and polyvinylpyrrolidone/vinyl acetate copolymers (PVP/VA) of different monomer weight ratios. The drug−polymer solubility at 25 °C was predicted using the Flory−Huggins model, from data obtained at elevated temperature using thermal analysis methods based on the recrystallization of a supersaturated amorphous solid dispersion and two variations of the melting point depression method. These predictions were compared with the solubility in the low molecular weight liquid analogues of the PVP/VA copolymer (N-vinylpyrrolidone and vinyl acetate). The predicted solubilities at 25 °C varied considerably depending on the method used. However, the three thermal analysis methods ranked the predicted solubilities in the same order, except for the felodipine−PVP system. Furthermore, the magnitude of the predicted solubilities from the recrystallization method and melting point depression method correlated well with the estimates based on the solubility in the liquid analogues, which suggests that this method can be used as an initial screening tool if a liquid analogue is available. The learnings of this important comparative study provided general guidance for the selection of the most suitable method(s) for the screening of drug−polymer solubility. / The Irish Research Council and Eli Lilly S.A. through an Irish Research Council Enterprise Partnership Scholarship for C.M.B., in part by The Royal Society in the form of Industrial Fellowship awarded to G.A., and in part by a research grant from Science Foundation Ireland (SFI) under Grant Number SFI/12/RC/2275 (for A.M.H., L.T., K.P., and A.K.).

No description available.

A unified and systematic study of one-dimensional heat conduction based on thermal relaxation is presented. Thermal relaxation is introduced through the constitutive equation (modified Fourier's law) which relates this heat flux and temperature. The resulting temperature and flux field equations become hyperbolic rather than the usual classical parabolic equations encountered in heat conduction. In this formulation, heat propagates at a finite speed and removes one of the anomalies associated to parabolic heat conduction, i.e., heat propagating at an infinite speed. In situations involving very short times, high heat fluxes, and cryogenic temperatures, a more exact constitutive relation must be introduced to preserve a finite speed to a thermal disturbance. The general one-dimensional temperature and flux formulations for the three standard orthogonal coordinate systems are presented. The general solution, in the temperature domain, is developed by the finite integral transform technique. The basic physics and mathematics are demonstrated by reviewing Taitel's problem. Then attention is turned to the effects of radially dependent systems, such as the case of a cylinder and sphere. Various thermal disturbances are studied showing the unusual physics associated with dissipative wave equations. The flux formulation is shown to be a viable alternative domain to develop the flux distribution. Once the flux distribution has been established, the temperature distribution may be obtained through the conservation of energy. Linear one-dimensional composite regions are then investigated in detail. The general temperature and flux formulations are developed for the three standard orthogonal coordinate systems. The general solution for the flux and temperature distributions are obtained in the flux domain using a generalized integral transform technique. Additional features associated with hyperbolic heat conduction are displayed through examples with various thermal disturbances. A generalized expression for temperature dependent thermal conductivity is introduced and incorporated into the one-dimensional hyperbolic heat equation. An approximate analytical solution is obtained and compared with a standard numerical method. Finally, recommendations for future analytical and experimental investigations are suggested. / Ph. D.

Earth radiation budget instruments are devices designed to study global climate change. These instruments use telescopes embarked on low-earth-orbit satellites to measure Earth emitted and reflected solar radiation. Radiation is sensed as temperature changes caused by radiation absorbed during scans of the earth on a delicate gold-black coated detector. This work is part of a larger effort to develop an end-to-end dynamic electro-thermal model, based on first-principles, for the next generation of earth radiation budget instruments, the Radiation Budget Instrument (RBI). A primary objective of this effort is to develop a numerical model of the detector to be used on RBI. Specifically, the sensor model converts radiation arriving at the detector, collimated and focused through telescopes, into sensible heat; thereby producing a voltage. A mathematical model characterizing this sensor is developed. Using a MATLAB algorithm, an implicit finite-volume scheme is implemented to determine the model solution. Model parameters are tuned to replicate experimental data using a robust parameter estimation scheme. With these model parameters defined, the electro-thermal sensor model can be used, in conjunction with the remaining components of the end-to-end model, to provide insight for future interpretation of data produced by the RBI. / Master of Science / Earth radiation budget instruments are devices designed to study global climate change. These instruments use telescopes embarked on low-earth-orbit satellites to measure radiation exiting the atmosphere of the Earth. As the atmospheric science community works to design and develop the next generation of these instruments, a need for a model capable of simulating operating performance has arisen. This work is part of a larger effort to develop a complete model for the next generation of Earth radiation budget instruments, the Radiation Budget Instrument (RBI). A primary objective of this effort is to develop a model of a detector to be used on the RBI. The modelling techniques used to characterize the detector are presented in this work. Once the model has been developed, optimal model parameters are determined to tune the model. With these model parameters defined, the detector model can be used, in conjunction with the remaining pieces of the overall end-to-end model, to provide insight for future interpretation of data produced by the RBI.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1949. / Vita. The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 8, 2010) Includes bibliographical references (p. 65).

No description available.

In the process of engine design, it is important for the engine designer to predict the accurate component temperatures. Controlling the temperature of engine components requires a better understanding of the coolant behaviour in the coolant jacket of an engine which is critical to internal combustion engine design, The studies reported in the literature emphasize the influence of the cooling system on other engine operation such as exhaust emission, fuel consumption and engine wear. In this context, much work has been done with the purpose of improving the coolant jacket design and components of the cooling system to achieve higher performance. (Some of these studies) Previous researches have shown the possibility of achieving higher engine efficiency and performance with higher coolant temperature. This project aims at understanding the coolant flow behaviour in the coolant jackets of a diesel engine and investigating the possibility of running the engine at higher coolant temperatures by predicting the temperature distribution of the structure which is required for the assessment of the durability ofthe engine components. In this thesis, CFD (Computational Fluid Dynamics) and FE (Finite Element) techniques are used to study coolant flow in the coolant jackets and to predict the temperature distribution within the engine structure respectively. The objectives are to develop an FE model of the engine structure for thermal analyses and a CFD model of the fluid domain for the coolant flow CFD analyses. A number of case studies are carried out with the purpose of determining the most suitable technique for accurate temperature prediction. The methodology of manual coupling approach between CFD and FE analyses, which is more widely used in industry, and conjugate approach are demonstrated. Using these approaches, thermal analysis of the engine is conducted with the purpose of identifying the thermally critical locations throughout the engine. Furthermore, the influences of higher coolant temperature on these thermally critical regions of the engine are highlighted by carrying out four case studies with coolant inlet temperatures of 110°C, !ISOC, 117.5"C and !20°C. The temperature rise at the particular points around thermally critical regions is found to be in the range of 3-9 degrees at the higher coolant temperatures. This slight increase in temperature of critical locations may affect the durability of the structure. However, without carrying out the structural analyses it is not possible to comment on the durability of the engine structure. The effects of surface roughness and viscosity on heat transfer rate are also investigated and shown to be insignificant.

De nombreux alliages de structure doivent leurs propriétés mécaniques à la présence de précipités inter ou intragranulaires. Ainsi les superalliages à base nickel, de matrice austénique γ, sont souvent renforcés par des précipités de phases intermétalliques ordonnées. Au sein de l’alliage Inconel 718, outre la phase γ’ de structure L12 (cubique simple), on trouve des précipités de Ni3Nb sous la forme métastable γ" (D022 - tétragonal centré) ou sous la forme stable δ (D0a - orthorhombique). Le rôle des précipités γ’, γ" et δ sur les propriétés macroscopiques de l'alliage est connu et largement utilisé en contexte industriel. Cependant les mécanismes de précipitation et de transformation de ces précipités ne sont toujours pas complètement élucidés, ce qui a motivé ce travail. La microstructure de l’alliage a été caractérisée par microscopie optique (MO) et électronique (à balayage et en transmission ; MEB et MET) dans l’état de livraison et après des traitements thermiques isothermes et anisothermes. Les essais d’analyse thermique différentielle (ATD) nous ont permis de préciser les domaines de température de précipitation et de dissolution des différentes phases présentes (γ’, γ" et δ). Différents états de précipitation ont été obtenus à l’aide de traitements thermiques isothermes basés sur les diagrammes temps-températuretransformation (T.T.T.) disponibles dans la littérature. Les observations en MET « à haute résolution » des précipités des phases δ et γ’’ ont permis de caractériser certains des défauts structuraux présents dans ces précipités. Nous montrons ainsi que les défauts d’empilement au sein de la phase γ’’ peuvent servir de germes pour la précipitation de . Alors que la structure des interfaces δ/γ ainsi que les défauts d’orientation au sein des lamelles de δ suggèrent que la croissance de la phase δ a lieu directement à partir de la matrice . / Many structural alloys are strengthened by the presence of precipitates in the grains or at grain boundaries. Nickel based superalloys often present an austenitic γ matrix in which ordered intermetallic phases precipitate. In the alloy Inconel 718, one can find γ’ L12 cubic ordered precipitates together with the compound Ni3Nb in its metastable form γ" (D022 - tetragonal) or the stable phase δ (D0a - orthorhombic). The incidence of those precipitates on macroscopic properties of the alloy 718 is well known and widely used in industrial applications. However the mechanisms responsible for the precipitation and transformation of these phases are not fully understood, which motivated the present study. The alloy microstructure has been observed by optical microscopy (OM) and electron microscopy (scanning and transmission, SEM and TEM) in the as received state as well as after heat treatment (isothermal and anisothermal). Differential thermal analysis (DTA) was used to determine the precipitation and dissolution temperatures of the phases γ', γ" and δ. Various precipitation microstructures were obtained by heat treatments based on available TTT diagrams. Some of the structural defects present in γ" and δ precipitates have been characterised by lattice imaging TEM observations. It is shown that stacking faults in γ’’ phase can act as a seed for the germination of . The structure of the δ/γ interface and the orientation defects in δ lamellae suggest that the growth of δ phase occurs directly from the matrix (and not by transformation of the γ’’ phase).

<p>Termalne osobine svinjskog mesa (Longissimus dorsi) osmotski dehidratisanog u melasi &scaron;ećerne repe i svežeg svinjskog mesa praćene su metodama termalne analize: Diferencijalnom skenirajućom kalorimetrijom (DSC), termogravimetrijskom analizom (TGA), modulovanom diferencijalnom skenirajućom kalorimetrijom (MDSC). Dobijeni rezultati pokazuju postojanje novonastale proteinske osnove osmotski dehidratisanog svinjskog mesa koji je posledica smanjenja količine vode i interakcije komponenti melase s proteinima mesa. Nađeno je da osmotskom dehidratacijom dolazi do promene i pregrupisavanja preostale slobodne vode u dva oblika, &scaron;to ukazuje na mehaničko strukturne promene u interfibrilarnoj mreži i pojednostavljivanje strukture proteinske osnove. Definisani su nastali strukturni nivoi proteinske osnove: strukturni nivo vode vezane na protein tj. postojanje proteinske strukture i posle osmotske dehidratacije -strukturni nivo I; strukturni nivo mreže sa ujednačeno manjim porama tj. nivo energetski jače vezane imobilizirane -strukturni nivo II; strukturni nivo mreže sa ujednačeno većim porama tj. nivo energetski slabije vezane imobilizirane -strukturni nivo III.<br />Ispitivanjem termalnih osobina uzoraka osmotski dehidratisanog mesa sa smanjenom vlagom ( ispod 20%) nađeno je postojanje staklastog prelaza po&scaron;to je najveća količina vode vezana za čvrsti matriks. Definisani su optimalni uslovi rehidratacije osmotski dehidratisanog svinjskog mesa, te su određene Pelegove konstante rehidratacije. Nađeno je postojanje nativnih struktura proteina u osmotski dehidtiranom mesu i određeni su kinetički parametri denaturacije (Ea, kb) svežeg i osmotski dehidriranog mesa. Određen je sadržaj makroelemenata osmotski su&scaron;enog svinjskog mesa. Radi obja&scaron;njenja složenosti interakcija proteina mesa i sastojaka osmotskog rastvora melase koje se odvijaju pri dehidrataciji, kao model sistem poslužila je interakcija proteina albumina goveđeg seruma (BSA) s jonima nekih makroelemenata prisutnih u melasi.</p> / <p>Thermal properties of pork meat (Longissimus dorsi) osmotically dehydrated in sugar beet molasses and fresh pork were followed by the methods of thermal analysis: Differential Scanning Calorimertry (DSC), Thermogravimetric Analysis (TGA), Modulated Differential Scanning Calorimetry (MDSC). The results indicate the existence of newly formed protein matrix as a consequence of osmotic dehydration of pork meat: reducing the amount of water and the interaction of the components of molasses and meat proteins. It has been found that changes were induced by the process of osmotic dehydration, and rearrangeement of the remaining free water in two forms. Also as a consequence of the osmotic dehydration, structural changes in the interfibrilar network and simplifying of the original structure of the meat protein matrix were occurred. A structural levels of protein matrix were defined: as structural level of the water bound to the protein, meaning the existence of protein structure and after osmotic dehydration Structural level I; a structural level with uniformly small pores in the network of formed protein matrix: energy level of more tightly immobilized water &ndash;Structural level II; and structural level of network with uniformly larger pores, energy level of lower bound immobilized water - Structural level III. By characterization of the thermal properties of the samples of osmotically dehydrated meat with reduced moisture (below 20%) the glass transition was found, as most of the water bound to a solid matrix.The optimal conditions for rehydration of dehydrated pork meat were defined, and Peleg&lsquo;s rehydration constants were obtained. It was found that the existence of the native structure of the protein in the osmotically dehydrated meat, and the kinetic parameters of protein denaturation (Ea, kb) of fresh and dehydrated meat were obtained. The content of macroelements in the osmotically dehydrated, fresh pork meat and in the sugar beet molasses were obtained. In order to explain the complexity of the interaction of meat proteins with the components of the osmotic solution -molasses that occur in the dehydration process, the model-system of the protein bovine serum albumin (BSA) interaction with the ions were implied to present simple interaction of some major elements with a protein matrix followed by DSC and ITC .</p>

Student Number : 0303610W - PhD thesis - School of Chemistry - Faculty of Science / Mesoporous MCM-48 was synthesized and used as a template to synthesize mesoporous carbon (MC) materials. Polystyrene, the carbon source, together with sulfuric acid and toluene were added to the template (160 oC for 6 h) and this procedure generated a low surface area carbon supported/MCM-48 material. A repeat addition and carbonization step was needed to form the precursor carbon/MCM-48 material that was pyrolysed at 900 oC to generate graphitic mesoporous carbon materials. After removal of the silica template, mesoporous carbons were characterized by XRD, HR-TEM, Raman spectroscopy and surface area analysis. The effect of the amount of polystyrene as well as the role of the pyrolysis temperature on the final product was investigated. This synthesis methodology can readily be controlled to produce partially ordered graphitic mesoporous carbon supports with predictable pore width and surface area. The methane selectivity was low (below 6%) and stable, and the overall olefin fraction was found to be good for all the supported catalysts studied. The potassium promoter increased the hydrocarbon chain growth to C68 giving α-1 and α-2 both between 0.79 and 0.90 for all supported catalysts with an exception of MCM-48 supported Fe catalyst that selectively produced hydrocarbons up to C28.