The melting points of rigid, hydrogen bonding, and non-hydrogen bonding organic compounds have been estimated from their chemical structure. The estimation was accomplished through the use of both additive and non-additive non-constitutive properties of the molecule. The melting points of the aforementioned compounds can be estimated by the equation: TM = TMPN + TIHBN + TPACK + 8.9*EXPAN + 73.1*SIGMAL + 196.3 where the dependent variable, TM, is the melting point of the compound in Kelvin, SIGMAL is the logarithm of the symmetry number for the molecule, EXPAN is the eccentricity of the molecule taken to the third power, TMPN is the summation of the melting point number for each functional group in the molecule, TIHBN is the summation of an intramolecular hydrogen bonding index and TPACK is a packing efficiency index. The solubility of naphthalene in binary, ternary, and quinary cosolvent-water mixtures was determined by HPLC analysis. The samples were equilibrated for 48 hours on a test tube rotator, centrifuged, diluted with acetonitrile, and then injected onto a C8 10 micron column. The cosolvent mixtures used were hydro-organic solutions consisting of water with either methanol, ethanol, isopropanol, acetone, acetonitrile, propylene glycol or a combination of these as the cosolvent. The propylene glycol-water mixtures were allowed to equilibrate for 10 days. In all cases, naphthalene solubilities in binary cosolvent mixtures were found to obey log-linear relationships: log X = SIGMA(FRAC) - log X(w) where X is the mole fraction solubility of naphthalene in the mixture, X(w) is the mole fraction solubility in pure water, FRAC is the volume fraction of the cosolvent, and SIGMA is the slope. SIGMA can be estimated by using the UNIFAC method to predict the solubility in 100% cosolvent and by using the generalized solubility equation of Yalkowsky to estimate the water solubility. These binary equations can then be used to generate ternary and higher multicomponent equations.

Three solution models: ideal, regular, and quasi- regular, were used to predict the melting point of eutectic mixtures containing Polyethylene Glycol (PEG) 400 and PEG 4000 with nine poorly water- soluble drugs: 1-naphthoic acid, estrone, griseofulvin, indomethacin, phenobarbital, paracetamol, salicylic acid, salicylamide and naproxen. PEG 400 was physically mixed with drug at different weight percentages to determine the melting points of the pure drugs and the melting point depression using Differential Scanning Calorimetry (DSC). The PEG 4000 eutectic mixtures were processed by the solvent evaporation method. In both the PEG 400 and PEG 4000 study, the quasi-regular solution model accounted for the most realistic conditions of entropy and enthalpy of the mixtures compared to ideal and regular solution models.

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An ultra-high burnup metallic inert matrix nuclear fuel concept is being characterized and evaluated by Lawrence Livermore National Laboratory based on a metal matrix fuel concept originally developed at the Bochvar Institute in Russia. The concept comprises a dispersion of uranium metal microspheres in a Zr-based alloy matrix that provides thermal bonding between the fuel particles and the cladding material. The objective of this study was to experimentally evaluate both the microstructural and thermophysical properties of Zr-Fe-Cu alloys. The experiments and analyses described were divided into three main parts, nominally based on the analysis methods used to examine the alloys. An Electron Probe Microanalyzer (EPMA) was used to characterize the metallurgical properties of the proposed matrix alloys. The groups of alloys were cast using a high temperature inert atmosphere furnace. The cast alloys showed the expected combination of phases with the exception of the ZrFe2 Laves phase which was predicted for the Zr-12Fe-15Cu1 alloy but was not detected. The Zr-12Fe-5Cu alloy consisted of a Zr solution phase dispersed in a matrix of two different intermetallic phases. The second alloy, Zr-12Fe-10Cu, did not produce a homogenous mixture and consisted of two distinct phase morphologies. The top half of the sample was Zr rich and contained Zr precipitates dispersed in a matrix of intermetallic compounds while the bottom half consisted solely of intermetallic compounds. The third alloy, Zr-12Fe-15Cu, was comprised of four different intermetallic phases three of which had the same apparent Zr_(2)(Fe,Cu) structure but had distinct phase morphologies based on the Backscatter Electron (BSE) images. Upon determining the phase morphologies of each of the fabricated alloys Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) were used to measure phase transformation and melting temperatures. Little difference was observed between the as-cast and annealed samples. The transitions shifted slightly to higher temperatures and the annealed Zr-12Fe-15Cu alloy only had two transitions compared to three seen in the as-cast samples. Slight changes were observed in the melting temperatures between the as-cast and annealed alloys. Zr-12Fe-5Cu had the largest melting temperature (886.3°C) while Zr-12Fe-10Cu had the smallest melting temperature (870°C). The third alloy, Zr-12Fe-15Cu, had a melting point just below that of Zr-12Fe-5Cu at 882.7°C. Light Flash Analysis (LFA) was implemented to determine the low temperature (20-260°C) thermal diffusivity values of each alloy. The as-cast measurements were more precise than the annealed samples, most likely the result of non-ideal sample integrity prior to loading. Each of the three alloys showed a linear increase in thermal diffusivity over the temperature range. Values for Zr-12Fe-5Cu ranged from 3.54 ± 0.06 mm2/s to 4.42 ± 0.10 mm^(2)/s. The Zr-12Fe-10Cu alloy had maximum and minimum values of 4.19 ± 0.22 mm^(2)/s and 3.17 ± 0.16 mm^(2)/s, respectively. Lastly, Zr-12Fe-15Cu had the largest thermal diffusivity ranging from 3.52 ± 0.15 mm^(2)/s at 20°C to 4.64 ± 0.16 mm_(2)/s at 260°C. Overall, the data from the LFA measurements showed that the Zr-Fe-Cu alloy system had similar diffusivity values compared to other common reactor materials.

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Thesis (Ph.D.) -- McMaster University, 1999. / Includes bibliographical references (leaves 231-245). Also available via World Wide Web.