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No / A precipitation process is considered in which completely miscible solution and supercritical antisolvent are passed through premixing and diluting zones of a turbulent flow. The influence of flow velocity on particle size and nuclei concentration is discussed in terms of mixing and precipitation time constants and their supersaturation dependencies. The proposed model allowed the major process parameters such as supersaturation profile, mixed fluid fraction and mean particle size to be calculated and compared with experimental data. For the crystallization system paracetamol/ethanol/CO2 studied, the supersaturation profile becomes established at Re104. The particle size and shape are defined, firstly, by increase of supersaturation and relative volume of mixed (on molecular scale) fluid with increase of flow velocity and, secondly, by decrease of residence time available for nucleation with increase of flow velocity. These competitive processes can result in minimum particle size at a defined flow rate.

Made available in DSpace on 2017-07-21T20:42:31Z (GMT). No. of bitstreams: 1 Edson Cezar Grzebielucka.pdf: 4989401 bytes, checksum: 3b7c0f98c460c25eaee95336ec0ea8bd (MD5) Previous issue date: 2009-11-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The powders synthesis of yttria-stabilized zirconia by chemical methods has enabled the reduction in particle size for the submicrometer-sized scale. This reduction is to improve the electrical and mechanical responses of electrolyte fuel cells. Contributing in this research, this work was to study the effects of temperature elimination of organic phases, to obtain powder of yttria stabilized zirconia, and the effect of time and sintering temperature on grain size of sintered bodies. The powders were obtained by two chemical routes: Pechini and PEG / AF, using 4.5 mol% of Y2O3 as a dopant. The properties of powders were made by X-ray Diffraction, Scanning Electron Microscopy and Infrared Spectroscopy and the sintered bodies were characterized by X-ray diffraction, scanning electron microscopy and density. It was observed that the coordination of metal ions with the polymer occurs through different ways, depending on the process used to obtain the post. The final microstructure has a greater influence than the sintering of treatments for removal of organics. The method of production of powders, temperature and calcination time change the size of the crystallites formed, and the largest variation in size occurs when increasing the calcination temperature. The final size of the grains obtained after sintering was about 1μm not influenced by the method or by the firing conditions for obtaining the post. Crystallite size obtained by Scherrer equation reported values between 5 and 8nm, and that the crystallite size tends to increase with time and temperature of heat treatment. / A síntese de pós de zircônia estabilizada com ítria por métodos químicos tem possibilitado a redução nos tamanhos de partículas para a escala submicrométrica. Esta redução visa melhorar as respostas elétricas e mecânicas dos eletrólitos de células a combustível. Contribuindo nesta linha de pesquisa, este trabalho teve como objetivo estudar os efeitos das temperaturas de eliminação das fases orgânicas, na obtenção de pós de zircônia estabilizada com ítria, e o efeito do tempo e temperatura de sinterização no tamanho de grão dos corpos sinterizados. Os pós foram obtidos por duas rotas químicas: Pechini e PEG/AF, utilizando 4,5% em mol de Y2O3 como dopante. As caracterizações dos pós foram feitas por Difração de raios X, Microscopia Eletrônica de Varredura e Espectroscopia no infravermelho e os corpos sinterizados foram caracterizados por Difração de raios X, Microscopia Eletrônica Varredura e Densidade Aparente. Observou-se que a coordenação dos íons metálicos com o meio polimérico ocorre de maneiras diferentes, dependendo do processo utilizado para a obtenção dos pós. A microestrutura final sofreu uma maior influência da sinterização do que dos tratamentos para eliminação dos orgânicos. O método de obtenção dos pós, a temperatura e o tempo de calcinação alteram o tamanho do cristalito formado, sendo que a maior variação de tamanho ocorre quando se aumenta a temperatura de calcinação. O tamanho final dos grãos após sinterização obtidos foi da ordem de 1μm não sendo influenciado pelo método ou pelas condições de calcinação para a obtenção dos pós. Os tamanhos de cristalitos obtidos através da equação de Scherrer reportaram valores entre 5 e 8nm, e que o tamanho de cristalito tende a aumentar com o tempo e temperatura de tratamento térmico.

The focus of this work is on the modeling and simulation of shock wave propagation in reactive metal powder mixtures. Reactive metal systems are non-explosive, solid-state materials that release chemical energy when subjected to sufficiently strong stimuli. Shock loading experiments have demonstrated that ultra-fast chemical reactions can be achieved in certain micron-sized metal powder mixtures. However, the mechanisms of rapid mixing that drive these chemical reactions are currently unclear. The goal of this research is to gain an understanding of the shock-induced deformation that enables these ultra-fast reactions. The problem is approached using direct numerical simulation. In this work, a finite element (FE) model is developed to simulate shock wave propagation in discrete particle mixtures. This provides explicit particle-level resolution of the thermal and mechanical fields that develop in the shock wave. The Ni/Al powder system has been selected for study. To facilitate mesoscale FE simulation, a new dislocation-based constitutive model has been developed to address the viscoplastic deformation of fcc metals at very high strain rates. Six distinct initial configurations of the Ni/Al powder system have been simulated to quantify the effects of powder configuration (e.g., particle size, phase morphology, and constituent volume fractions) on deformation in the shock wave. Results relevant to the degree of shock-induced mixing in the Ni/Al powders are presented, including specific analysis of the thermodynamic state and microstructure of the Ni/Al interfaces that develop during wave propagation. Finally, it is shown that velocity fluctuations at the Ni/Al interfaces (which arise due to material heterogeneity) may serve to fragment the particles down to the nanoscale, and thus provide an explanation of ultra-fast chemical reactions in these material systems.

D. Tech. Chemical and Metallurgica Engineering. / Discusses the development highly corrosion resistant multi-functional materials for automobile applications by using laser surface alloying of aluminium substrate with a combination of metallic and ceramic powdery materials.

Chan, Ka Man Carmen. / "October 2009." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 160-165). / Abstracts in English and Chinese. / Table of Contents --- p.I / Acknowledgements --- p.IV / Abstract --- p.V / Abstract (Chinese version) --- p.VIII / List of Figures --- p.X / List of Tables --- p.XVIII / Chapter Chapter One. --- Introduction / Chapter 1.1 --- Pulmonary drug delivery --- p.1 / Chapter 1.2 --- Inhalation drug delivery systems --- p.4 / Chapter 1.3 --- Dry powder inhalation aerosols --- p.5 / Chapter 1.3.1 --- Principle of operation of DPIs --- p.5 / Chapter 1.3.2 --- Aerodynamic diameter --- p.6 / Chapter 1.3.2.1 --- Fine particle fraction --- p.8 / Chapter 1.3.3 --- Dispersibility --- p.8 / Chapter 1.3.4 --- Factors that affect dispersibility --- p.9 / Chapter 1.3.4.1 --- Particle Size --- p.9 / Chapter 1.3.4.2 --- Particle Density and Morphology --- p.10 / Chapter 1.3.4.3 --- Interparticulate interactions一Cohesion and adhesion --- p.11 / Chapter 1.3.4.3.1 --- Surface energetics --- p.11 / Chapter 1.3.4.3.2 --- Effect of hygroscopicity and electrostatic charges --- p.12 / Chapter 1.4 --- Particle formation techniques for DPI formulation --- p.14 / Chapter 1.4.1 --- Spray-drying --- p.14 / Chapter 1.4.2 --- Surface modification --- p.16 / Chapter 1.5 --- Physical characterization --- p.17 / Chapter 1.5.1 --- Laser diffraction --- p.17 / Chapter 1.5.2 --- X-ray powder diffraction --- p.18 / Chapter 1.5.3 --- Thermal analysis --- p.19 / Chapter 1.5.4 --- Particle morphology and surface area --- p.20 / Chapter 1.5.5 --- In vitro aerosol performance --- p.21 / Chapter 1.6 --- Surface characterization --- p.21 / Chapter 1.6.1 --- X-ray photoelectric spectroscopy (XPS) --- p.21 / Chapter 1.6.2 --- Inverse gas chromatography --- p.22 / Chapter 1.7 --- Atomic force microscopy in pharmaceutical science --- p.23 / Chapter 1.7.1 --- Principle of operation --- p.24 / Chapter 1.7.1.1 --- Tapping mode --- p.27 / Chapter 1.7.1.2 --- Contact mode --- p.27 / Chapter 1.8 --- Scope of thesis --- p.29 / Chapter Chapter Two. --- Materials and Methods / Chapter 2.1 --- Materials --- p.32 / Chapter 2.2 --- Methods --- p.32 / Chapter 2.2.1 --- Optimization of spray-drying parameters --- p.32 / Chapter 2.2.2 --- Preparation of spray-dried salbutamol sulphate powders containing different concentrations of amino acid additive --- p.33 / Chapter 2.2.3 --- Physical characterization of spray-dried powders --- p.34 / Chapter 2.2.3.1 --- Particle size and size distribution --- p.34 / Chapter 2.2.3.2 --- Specific surface area --- p.35 / Chapter 2.2.3.3 --- X-ray powder diffraction --- p.35 / Chapter 2.2.3.4. --- Scanning electron microscopy --- p.36 / Chapter 2.2.3.5. --- Thermal analysis --- p.36 / Chapter 2.2.3.5.1 --- Thermogravimetric analysis (TGA) --- p.36 / Chapter 2.2.3.5.2 --- Differential scanning calorimetry (DSC) --- p.36 / Chapter 2.2.3.6 --- Water vapour sorption isotherm --- p.37 / Chapter 2.2.3.7 --- Density measurements --- p.37 / Chapter 2.2.3.8 --- In vitro particle deposition (MSLI) --- p.38 / Chapter 2.2.4 --- Surface characterization of the spray-dried powders --- p.39 / Chapter 2.2.4.1 --- X-ray photoelectric spectroscopy (XPS) --- p.39 / Chapter 2.2.4.2 --- Surface energy measurement by inverse gas chromatography (IGC) --- p.40 / Chapter 2.2.4.2.1 --- Calculation of standard free energy of adsorption --- p.41 / Chapter 2.2.4.2.2 --- Dispersive component of surface free energy and related thermodynamic parameters --- p.42 / Chapter 2.2.4.2.3 --- Specific interactions and associated acid-base properties --- p.43 / Chapter 2.2.5. --- Atomic Force Microscopy (AFM) --- p.43 / Chapter 2.2.5.1. --- Imaging --- p.43 / Chapter 2.2.5.2. --- Force measurements --- p.44 / Chapter 2.2.5.2.1 --- Adhesion force measurements --- p.44 / Chapter 2.2.5.2.2 --- Force curve data conversions --- p.44 / Chapter Chapter Three. --- "Optimal Spray-drying Conditions, Physical Characterization and Aerosol Performance of Additive-modified Spray-dried Salbutamol Sulphate particles" / Chapter 3.1 --- Optimization of spray-drying conditions --- p.46 / Chapter 3.2 --- Effect of phenylalanine on the spray-dried SS particles --- p.52 / Chapter 3.2.1. --- Phenylalanine as the additive --- p.52 / Chapter 3.2.1.1 --- In vitro aerosol performance --- p.53 / Chapter 3.2.1.2 --- Particle morphology --- p.55 / Chapter 3.2.1.3 --- Crystallinity --- p.62 / Chapter 3.2.1.4 --- Particle size distribution and specific surface area --- p.63 / Chapter 3.2.1.5 --- Density --- p.65 / Chapter 3.2.1.6 --- Thermal analysis --- p.66 / Chapter 3.2.1.7 --- Water vapour isotherm --- p.70 / Chapter 3.3 --- Effect of leucine on the spray-dried SS particles --- p.77 / Chapter 3.3.1. --- L-Leucine as the additive --- p.77 / Chapter 3.3.1.1 --- In vitro aerosol performance --- p.78 / Chapter 3.3.1.2 --- Particle morphology --- p.80 / Chapter 3.3.1.3 --- Crystallinity --- p.86 / Chapter 3.3.1.4 --- Particle size distribution and specific surface area --- p.87 / Chapter 3.3.1.5 --- Density --- p.90 / Chapter 3.3.1.6 --- Thermal analysis --- p.92 / Chapter 3.3.1.7 --- Water vapour isotherm --- p.95 / Chapter Chapter Four. --- Surface Characterization of Additive-modified Spray-dried Salbutamol Sulphate Particles / Chapter 4.1 --- X-ray photoelectric spectroscopy --- p.103 / Chapter 4.1.1 --- Phenylalanine --- p.103 / Chapter 4.1.2 --- Leucine --- p.104 / Chapter 4.2 --- Inverse gas chromatography --- p.105 / Chapter 4.2.1 --- Phenylalanine --- p.105 / Chapter 4.2.2 --- Leucine --- p.107 / Chapter 4.3 --- Atomic force microscopy --- p.109 / Chapter 4.3.1 --- Surface topography --- p.109 / Chapter 4.3.2 --- Adhesive force measurements --- p.118 / Chapter Chapter Five. --- Conclusions and Suggestions for Future Works / Chapter 5.1 --- Conclusions --- p.139 / Chapter 5.1.1 --- Physical properties --- p.139 / Chapter 5.1.2 --- Surface characteristics and aerosol performance --- p.140 / Chapter 5.2 --- Future studies --- p.142 / Appendix --- p.143 / References --- p.160

Chan, Pui. / "November, 2009." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 108-114). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgement --- p.vi / Abstract --- p.vii / Abstract (Chinese) --- p.ix / Chapter Chapter One --- Introduction / Chapter 1.1. --- Pulmonary Route for Drug Delivery --- p.2 / Chapter 1.2. --- Factors Affecting the Performance of Inhaled Formulations --- p.3 / Chapter 1.2.1. --- Particle Aerodynamic Diameter --- p.4 / Chapter 1.2.2. --- Dispersibility of Particles --- p.5 / Chapter 1.2.3. --- Clearance Mechanism in Lung and Dissolution of Particles --- p.6 / Chapter 1.3. --- Production of Dry Powder Inhalation by Spray Drying --- p.7 / Chapter 1.4. --- Approaches to Enhance Aerosol Performance of Spray Dried Particles --- p.8 / Chapter 1.4.1 --- Porous/Hollow Particles --- p.9 / Chapter 1.4.2 --- Non-Porous Corrugated Particles --- p.10 / Chapter 1.4.3 --- Blends and Ternary Systems --- p.10 / Chapter 1.4.4 --- Surface Energy and Crystallinity Modification --- p.11 / Chapter 1.4.5 --- Other Approaches to Enhancing Aerosol Performance --- p.12 / Chapter 1.5 --- Objectives and Rationale of the Present Study --- p.13 / Chapter 1.6 --- Scope of Present Study and Particle Characterization Techniques Employed --- p.14 / Chapter 1.6.1 --- Microscopy and Particle Density Measurements --- p.14 / Chapter 1.6.2 --- Particle Size Analysis and Particle Dispersibility --- p.15 / Chapter 1.6.3 --- Thermal Analysis and Particle Crystallinity --- p.15 / Chapter 1.6.4 --- Particle Surface Characterization --- p.16 / Chapter 1.6.5 --- Inverse Gas Chromatography --- p.18 / Chapter 1.6.6 --- Fractal Analysis --- p.19 / Chapter 1.6.6.1 --- Background and Origin of Fractal Analysis --- p.19 / Chapter 1.6.6.2 --- Use of Fractal Analysis in Pharmaceutical Research --- p.20 / Chapter 1.6.6.3 --- Methods for fractal analysis --- p.21 / Chapter 1.6.7 --- Atomic Force Microscopy --- p.23 / Chapter 1.6.7.1 --- Background of Atomic Force Microscopy --- p.23 / Chapter 1.6.7.2 --- Characterization of Surface Topography by Atomic Force Microscopy --- p.23 / Chapter 1.6.7.3 --- Measurement of Interaction Forces by Colloid Probe 226}0Ø Microscopy --- p.25 / Chapter 1.6.7.4 --- Use of Atomic Force Microscopy in Pharmaceutical Research --- p.27 / Chapter Chapter Two --- Materials and Methods / Chapter 2.1. --- Materials --- p.30 / Chapter 2.2. --- Equipment --- p.31 / Chapter 2.3. --- Methods --- p.33 / Chapter 2.3.1. --- Powder Preparation --- p.33 / Chapter 2.3.1.1 --- Preparation of Salbutamol Sulphate Samples --- p.33 / Chapter 2.3.1.2 --- Preparation of Disodium Cromoglycate Samples --- p.33 / Chapter 2.3.1.3 --- Preparation of ß-Galactosidase (BG) Samples --- p.34 / Chapter 2.3.2. --- Determination of Aerosol Performance --- p.35 / Chapter 2.3.3. --- Determination of Protein Activity for BG Samples --- p.36 / Chapter 2.3.3.1. --- Enzyme Assay Procedure --- p.37 / Chapter 2.3.3.2. --- Calculation of Enzyme Activity --- p.38 / Chapter 2.3.3.3. --- Determination of Enzyme Activity Retained in Spray-dried Samples --- p.38 / Chapter 2.3.4. --- Physicochemical Characterization of Particles --- p.39 / Chapter 2.3.4.1. --- Scanning Electron Microscopy --- p.39 / Chapter 2.3.4.2. --- Particle Density Determination --- p.39 / Chapter 2.3.4.3. --- Particle Size Analysis --- p.40 / Chapter 2.3.4.4. --- Thermal analysis --- p.41 / Chapter 2.3.4.5. --- Powder X-ray Diffraction --- p.42 / Chapter 2.3.4.6. --- Surface Area Determination --- p.42 / Chapter 2.3.4.7. --- Surface Composition Characterization --- p.43 / Chapter 2.3.4.8. --- Surface Tension Measurement --- p.44 / Chapter 2.3.4.9. --- Inverse Gas Chromatography --- p.45 / Chapter 2.3.4.9.1. --- Calculation of Standard Free Energy of Adsorption --- p.46 / Chapter 2.3.4.9.2. --- Calculation of Dispersive Component of Surface Free Energy --- p.47 / Chapter 2.3.4.9.3. --- Determination of Specific Interactions and Associated Acid-Base Properties --- p.48 / Chapter 2.3.4.10. --- Fractal Analysis --- p.49 / Chapter 2.3.4.11. --- Atomic Force Microscopy --- p.49 / Chapter Chapter Three --- Results / Chapter 3.1. --- In vitro Aerosol Performance --- p.52 / Chapter 3.2. --- Enzyme Activity Retained in BG Samples --- p.55 / Chapter 3.3. --- Scanning Electron Microscopy (SEM) --- p.56 / Chapter 3.3.1. --- SEM of Salbutamol Sulphate Formulations --- p.56 / Chapter 3.3.2. --- SEM of DSCG Formulations --- p.59 / Chapter 3.3.3. --- SEM of BG Formulations --- p.61 / Chapter 3.4. --- Density Measurements --- p.65 / Chapter 3.4.1. --- Densities of Salbutamol Sulphate Formulations --- p.65 / Chapter 3.4.2. --- Densities of DSCG Formulations --- p.66 / Chapter 3.4.3. --- Densities of BG Formulations --- p.67 / Chapter 3.5. --- Particle Size Analysis by Laser Diffraction --- p.68 / Chapter 3.5.1. --- Volume Mean Diameter Measurements --- p.68 / Chapter 3.5.2. --- Particle Size Distributions and Dispersion Patterns of Formulations --- p.70 / Chapter 3.6. --- Thermal Analysis --- p.75 / Chapter 3.7. --- Powder X-ray Diffraction --- p.80 / Chapter 3.8. --- Surface Area Measurements --- p.84 / Chapter 3.9. --- Surface Composition Characterization --- p.85 / Chapter 3.9.1. --- Surface Composition of Salbutamol Sulphate Formulations --- p.85 / Chapter 3.9.2. --- Surface Composition of DSCG Formulations --- p.88 / Chapter 3.9.3. --- Surface Composition of BG/BSA Formulations --- p.89 / Chapter 3.10. --- Surface Tension Measurements --- p.91 / Chapter 3.11. --- Inverse Gas Chromatography --- p.92 / Chapter 3.12. --- Fractal Analysis --- p.93 / Chapter 3.13. --- Atomic Force Microscopy --- p.94 / Chapter Chapter Four --- Discussion / Chapter 4.1. --- Influence of BSA on Aerosol Performance and Protein Integrity --- p.98 / Chapter 4.2. --- Influence of BSA on Physicochemical Properties of Particles --- p.98 / Chapter 4.2.1. --- Influence of BSA on surface corrugation --- p.98 / Chapter 4.2.2. --- Influence of BSA on particle size and dispersion behavior --- p.99 / Chapter 4.2.3. --- Influence of BSA on crystallinity and thermal properties of particles --- p.100 / Chapter 4.2.4. --- Influence of BSA on surface energetics of particles --- p.100 / Chapter 4.3. --- Relationship between Surface Corrugation and Aerosol Performance --- p.101 / Chapter 4.4. --- Mechanism of Surface Modification for BSA on Spray-dried Particles --- p.103 / Chapter Chapter Five --- Conclusions and Future Work / Chapter 5.1. --- Conclusions --- p.106 / Chapter 5.1.1. --- General Aerosolization-Enhancing Effect of BSA --- p.106 / Chapter 5.1.2. --- Surface Modifying Effect of BSA --- p.106 / Chapter 5.1.3. --- Relationship between Surface Corrugation and Aerosol Performance --- p.106 / Chapter 5.2. --- Future Work --- p.107 / References --- p.108