Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 161-164). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 132-139).

No description available.

No description available.

An investigation into the potential of time-wavelength resolved luminescence spectroscopy for the analysis of inorganic powders was performed. A time-wavelength resolved luminescence spectrometer consisting of an excimer laser, scanning monochromator, and gated integrator was constructed. The spectrometer had wavelength coverage from 265 nm to 800 nm, it was capable of measuring lifetimes between 100 ns and 500 ms. Sample excitation was done at 193 nm and 248 nm. A luminescence system model of first order decay in the time domain and a Gaussian function for the emission band was assumed. The time-wavelength resolved luminescence spectrum was described by the parameters: lifetime, peak maxima, peak halfwidth, and intensity factor. Parameter estimation was done with an algorithm employing a linear algebra construct and simplex optimization. The algorithm's performance on highly overlapped spectra was evaluated. For two component mixtures having a 1 % RSD noise level, overlaps greater than 0.3 halfwidths in the spectral domain and lifetime ratios greater than 1:1.3 were resolved with all parameter estimates having an error of less than ±2%. The luminescence spectra of CaMo0₄, SrMo0₄, BaMo0₄, ZnMoO₄, CdMo0₄, PbMoO₄, CaWO₄, SrW0₄, BaWO₄, ZnWO₄, CdW0₄ and PbWO₄ consisted of broad featureless bands showing simple exponential decay. Mixed crystals of Ca(MOxW₁-x)O₄ and Sr(MOxW₁-x)0₄ were examined. Tungstate emission was quenched by molybdate, the molybdate emission dominated when x was greater than 0.15. The tungstate lifetime was found to be proportional to molybdate concentration. The luminescence spectra of CaZrO₃, SrZr O₃, BaZr O₃ CaHfO₃ SrHfO₃, BaHfO₃, CaO, SrO, and BaO as pure compounds and doped with T1, Pb, Sb, and Bi were studied. The pure zirconates and hafnates showed short lived (<100 ns) luminescence with 248 not excitation; no readily discernible luminescence was observed with 193 nm excitation. Doped compounds tended to show luminescence characteristic of the dopant ion. / Science, Faculty of / Chemistry, Department of / Graduate

Yes / Granulation is commonly used as an enlargement process of particles produce granules with desirable characteristics and functionality. Granulation process transforms fine powders into free-flowing, dust-free granules with the presence of liquid binder at certain operating conditions. The main focus of this research is on seeded granulation of detergent powders, a new phenomenon of granulation in which a layer of fine powders surround the coarse particle. This is already proven for calcium carbonate (Rahmanian et al., 2011). Here, detergent granules were produced in a 5 L high shear Cyclomix granulator using different fine/coarse powder ratio (1/3, 1, 3) and different binder ratio of 10 %, 20 % and 30 %. The granules were then characterized for their particle size distribution, strength and structure. It was found that a high percentage (70 wt. %) of granules in the desired size range between 125 - 1,000 µm were produced using the powder ratio of 1/3 and a binder content of 10 %. Low mean crushing strength (3.0 N) with a narrow distribution was obtained using this condition. Structure characterization of the detergent granules produced in the granulator shows that consistent seeded granule structures are produced under the optimum process and formulation conditions of 1/3 powder ratio with 10 % binder.

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.

This project has investigated the mechanism of caking of lactose and identified some possible solutions to minimise caking of lactose and dairy powders, additional to those suggested in the literature. A background to lactose and caking is given. The problems of caking are identified and discussed. The project adds information to the knowledge on the polymorphic forms of lactose and their inter-relationships due to moisture sorption and processes such as milling. This information and many others in the literature are used to complete the simplified lactose conversion diagram developed by King [1965] and improved by Walstra, et al. [1999], which has been widely used in the literature as a guide for lactose manufacturing, processing, and storage. / Doctor of Philosophy (PhD)

Graduation date: 1997