Abstract
Research is summarized on fuel, fertile, and cladding materials. Results of studies in the field of solid state sciences are also reported. It was found during the studies on the thermal diffusion release of /sup 133/Xe from irradiated thoria--urania powders that during prolonged annealing at high temperatures, there were several sudden burst releases of /sup 133/Xe as a function of time. These sudden bursts appear to be related to the particle size of the powders. Studies on the phase composition of U/sub 3/O/sub 8//su established that the phase obtained at room temperature after heating at 850 deg K is always oxygen deficient. Results of studies on the different modifications of U/sub 3/O/sub 8/ indicated that the so-called delta-phase has a crystal structure almost identical with the beta-phase, yet there were differences in the heats of transition of each of these phases to the alpha-U/sub 3/O/sub 8/ phase at 130 deg C. Studies on fast neutron damage in stainless steel were initiated and results related to damage by void formation were obtained even when the fluencies were only moderately high. Studies on the phase transformations in solids brought out the unusual phase transition behavior of KNO/sub 3/. It was established that
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None.
Solid State Studies Section.
India: N. p.,
1973.
Web.
None.
Solid State Studies Section.
India.
None.
1973.
"Solid State Studies Section."
India.
@misc{etde_4938492,
title = {Solid State Studies Section}
author = {None}
abstractNote = {Research is summarized on fuel, fertile, and cladding materials. Results of studies in the field of solid state sciences are also reported. It was found during the studies on the thermal diffusion release of /sup 133/Xe from irradiated thoria--urania powders that during prolonged annealing at high temperatures, there were several sudden burst releases of /sup 133/Xe as a function of time. These sudden bursts appear to be related to the particle size of the powders. Studies on the phase composition of U/sub 3/O/sub 8//su established that the phase obtained at room temperature after heating at 850 deg K is always oxygen deficient. Results of studies on the different modifications of U/sub 3/O/sub 8/ indicated that the so-called delta-phase has a crystal structure almost identical with the beta-phase, yet there were differences in the heats of transition of each of these phases to the alpha-U/sub 3/O/sub 8/ phase at 130 deg C. Studies on fast neutron damage in stainless steel were initiated and results related to damage by void formation were obtained even when the fluencies were only moderately high. Studies on the phase transformations in solids brought out the unusual phase transition behavior of KNO/sub 3/. It was established that the phase transformation attributed to the orthorhombic (II) to the trigonal (I) transition at 129 deg C is essentially a 2-step transition. Results of differential scanning colorimeter (DSC) studies also revealed a peculiar feature which is as yet not understood, namely that on cooling, differential thermal analysis (DTA) showed a III to II phase transition; this is not seen in the DSC. The capabilities of the DSC technique to delineate temperatures of magnetic transitions were demonstrated by studying the transitions in a number of standard substances (metals, alloys, and compounds). In studies on KMnF/sub 3/, it was further demonstrated that the DSC technique is superior in measuring and detecting the heats of crystallographic and magnetic transitions. Heats of transition as small as 2 cal/mole were detected. Studies on the thermodynamics of high temperature materials showed the effects of water vapor on the volatility of U/sub 3/O/sub 8/ phase. Similar studies were completed on germanium oxide and Group IV oxides. Phase transformation in lanthanum cobaltate was deiineated by solid galvanic cell techniques and the free energy formation was calculated. Electrical properties of polycrystalline NiTe thin films showed that the electrical resistivity, temperature coefficient of resistance, and the Hall coefficient were functions of the film thickness. Work has been initiated to use these thin films for developing gauss-meters. In the field of instrumentation, efforts were directed on the microthermogravimetric system incorporating the Sartorius Model 4102 thermobalance. The system, as developed, is capable of continuous operation at 1 microgram sensitivity in static air or vacuum up to 1000 deg C or at 5 microgram sensitivity in flowing gases. In theoretical work the s --d mixing model was used to derive spin wave dispersion relation and obtain the shape of the optical absorption spectrum in transition metals. Spin wave dispersion relations were derived for Mn/sub x/Co/ sub 1-x/F/sub 2/ and gave qualitative agreement with experiment. The Hartree-- Fock and Unrestricted Hartree-- Fock calculations on H/sub 2/ were extended to include configuration interaction. The semilocalized orbital method was extended to HeH/sup +/. (auth)}
place = {India}
year = {1973}
month = {Dec}
}
title = {Solid State Studies Section}
author = {None}
abstractNote = {Research is summarized on fuel, fertile, and cladding materials. Results of studies in the field of solid state sciences are also reported. It was found during the studies on the thermal diffusion release of /sup 133/Xe from irradiated thoria--urania powders that during prolonged annealing at high temperatures, there were several sudden burst releases of /sup 133/Xe as a function of time. These sudden bursts appear to be related to the particle size of the powders. Studies on the phase composition of U/sub 3/O/sub 8//su established that the phase obtained at room temperature after heating at 850 deg K is always oxygen deficient. Results of studies on the different modifications of U/sub 3/O/sub 8/ indicated that the so-called delta-phase has a crystal structure almost identical with the beta-phase, yet there were differences in the heats of transition of each of these phases to the alpha-U/sub 3/O/sub 8/ phase at 130 deg C. Studies on fast neutron damage in stainless steel were initiated and results related to damage by void formation were obtained even when the fluencies were only moderately high. Studies on the phase transformations in solids brought out the unusual phase transition behavior of KNO/sub 3/. It was established that the phase transformation attributed to the orthorhombic (II) to the trigonal (I) transition at 129 deg C is essentially a 2-step transition. Results of differential scanning colorimeter (DSC) studies also revealed a peculiar feature which is as yet not understood, namely that on cooling, differential thermal analysis (DTA) showed a III to II phase transition; this is not seen in the DSC. The capabilities of the DSC technique to delineate temperatures of magnetic transitions were demonstrated by studying the transitions in a number of standard substances (metals, alloys, and compounds). In studies on KMnF/sub 3/, it was further demonstrated that the DSC technique is superior in measuring and detecting the heats of crystallographic and magnetic transitions. Heats of transition as small as 2 cal/mole were detected. Studies on the thermodynamics of high temperature materials showed the effects of water vapor on the volatility of U/sub 3/O/sub 8/ phase. Similar studies were completed on germanium oxide and Group IV oxides. Phase transformation in lanthanum cobaltate was deiineated by solid galvanic cell techniques and the free energy formation was calculated. Electrical properties of polycrystalline NiTe thin films showed that the electrical resistivity, temperature coefficient of resistance, and the Hall coefficient were functions of the film thickness. Work has been initiated to use these thin films for developing gauss-meters. In the field of instrumentation, efforts were directed on the microthermogravimetric system incorporating the Sartorius Model 4102 thermobalance. The system, as developed, is capable of continuous operation at 1 microgram sensitivity in static air or vacuum up to 1000 deg C or at 5 microgram sensitivity in flowing gases. In theoretical work the s --d mixing model was used to derive spin wave dispersion relation and obtain the shape of the optical absorption spectrum in transition metals. Spin wave dispersion relations were derived for Mn/sub x/Co/ sub 1-x/F/sub 2/ and gave qualitative agreement with experiment. The Hartree-- Fock and Unrestricted Hartree-- Fock calculations on H/sub 2/ were extended to include configuration interaction. The semilocalized orbital method was extended to HeH/sup +/. (auth)}
place = {India}
year = {1973}
month = {Dec}
}