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Full-Text Articles in Materials Chemistry

Evaluation Of Low-Temperature Fluoride Routes To Synthesize Actinide Nitrides And Oxide Solid Solutions, Gunanda Waduge Chinthaka Silva May 2009

Evaluation Of Low-Temperature Fluoride Routes To Synthesize Actinide Nitrides And Oxide Solid Solutions, Gunanda Waduge Chinthaka Silva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actinide mononitrides have been considered as a possible nuclear fuel for the Generation-IV nuclear reactor systems. In the process of evaluating these actinide mononitrides as nuclear fuel, it is important to study different chemical and physical characteristics of these compounds. Synthesis of the materials is thus important. Carbothermic reduction is one of the techniques that have been used to synthesize actinide mononitrides. In this method, a mixture of actinide oxide such as UO 2 and excess carbon is heat treated at temperatures greater than 1700 °C under a nitrogen atmosphere. The technique is however not promising in synthesizing the actinide …


The Synthesis And Systematic Evaluation Of Modified Polymeric Foams And Electrically Conductive Polyimide/Carbon/Metal Films, John Macharia Kinyanjui May 2009

The Synthesis And Systematic Evaluation Of Modified Polymeric Foams And Electrically Conductive Polyimide/Carbon/Metal Films, John Macharia Kinyanjui

UNLV Theses, Dissertations, Professional Papers, and Capstones

Thermally processed PU foams are examined as a function of processing temperatures (25, 45, 65, and 85°C) at the side, middle, and center of a simple cylindrical mold. The PU foams show both chemical and morphological differences as a function of the processing temperature and radial position within the mold. Thermal degradation of uretoneimine structures, the emergence of carbodiimide structures, and extent of reaction of isocyanate groups are measured using photoacoustic FTIR spectroscopy. Chemical gradients and morphology differences between the side, middle, and center of the molded foam are observed for all processing temperatures. The data indicate that thermal activation …