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Abstract  

Linear relationship were found among the plots of ΔH T ad and ΔG 0 T ad vs. the adiabatic reaction temperature (T ad) for transition metals carbides and silicides characterised by the same stoichiometry. The slope of the straight line depends on the product stoichiometry.

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Introduction Uranium–plutonium mixed carbides have been successfully irradiated up to a burn-up of 159 GWd/t in the Fast Breeder Test Reactor (FBTR) in Kalpakkam for the first time in the world. FBTR uses a high plutonium

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recycle the industrial wastes to reduce environmental pollution and save valuable resources [ 19 ]. China produces the largest amount of calcium carbide (CaC 2 ) through reaction of calcined limestone (CaO) with coal char (C). About 70% of the ethyne gas

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Abstract  

A simple radiochemical method has been developed for the phase analysis of hydrolysable carbides. The method is based on the radio gas chromatography of gaseous products of carbide hydrolysis with simultaneous mass and activity detection. The tritium-labelled hydrocarbons evolved (tritium oxide used for hydrolysis) are characteristic of the individual carbide phases. An application for Group III b carbide phase analysis is demonstrated.

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and their location, and the zeolite channel structure are important to the catalytic performance. The carbide species have been identified as the active center for methane activation, whereas surface acid sites are responsible for the

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Hard-metals are powder metallurgical composites made from carbides or carbonitrides of refractories with minor amounts of a ductile binder phase. Their thermal conductivity is very important as concerns their behaviour under thermomechanical loading in use. For practicable and quick measurement, a stationary method and a non-stationary one were introduced. The experimental results show that the thermal conductivity of hard-metals varies over the wide range between 10 and 100 Wdeg−1m−1, mainly reflecting the nature of the hard phase and its defect structure. The dependences on the position of the refractory in the Periodic Table and on the stoichiometry are discussed. For hard-metals based on titanium carbide, the thermal conductivity is proportional to the electrical one, i.e. the Wiedemann-Franz law holds with a modified Lorentz factor.

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Abstract  

The dissolution of carbide fuels was tried with the aid of various oxidants like H2O2, NaBiO3, (NH4)2Ce(NO3)6, (NH4)2S2O8, and AgO in nitric acid medium. During the dissolution, the carbon dioxide liberated has been measured. Among the oxidants studied, H2O2 and NaBiO3 appeared to be more effective for dissolution of carbides. 200–300 mg of sintered uranium carbide sample dissolved within 15 minutes in the presence of oxidants H2O2 or NaBiO3. Mixed carbide sample (70%) was dissolved within 30 min, whereas plutonium carbide required more than one hour. From the resulting solutions uranium and plutonium could be determined by conventional redox methods. More than 97% of plutonium could be recovered and purified from the resulting carbide solutions by conventionally used anion exchange method.

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material for structural applications in fusion technology. SiC f /SiC composite is composed of silicon carbide fiber (14 μm diameter of fibers) bundles. These bundles are woven in three dimensional textures and embedded in a silicon carbide matrix

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Abstract  

A model of slag refining processes and a method of determining the reduction capability of slag solutions are presented. Carbide slags were analysed by DTA methods.

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Abstract  

Samples of a catalyst CA-1 for ammonia synthesis were studied. After reduction the samples were treated with CO2 or with a mixture of 1% O2+2.4% H2O+CO2 at temperatures between 600 and 783 K. Mössbauer spectroscopy data indicate that above 600 K carbide phases and magnetite are formed. A probable mechanism for carbide formation is suggested.

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