The powder metallurgical processing of uranium-6 niobium (U-6Nb) alloy has undergone 3 years of characterization at the Oak Ridge Y-12 Plant. The current structure of the powder metallurgy (P/M) alloy has been described as duplex: a mixture of two or more distinct grain sizes. An experiment was conducted to determine a gamma stabilizing heat treatment (time and temperature combination) to produce a structure consisting of one gamma grain size. Two heat treatments were found to produce an irregular ASTM 4 grain size. Additional P/M U-6Nb alloy material was hot pressed and characterized using the two new heat treatments; however, the resulting microstructures were size ASTM 8. Mechanical properties of the fine-grained P/M material were characterized. Continued evaluation of these results did not determine the cause of the grain refinement.

Hydrothermal systems are often studied by collecting thermal gradient data and temperature-depth curves. These data contain important information about the flow field, the evolution of the hydrothermal system, and the location and nature of the ultimate heat sources. Thermal data are conventionally interpreted by the ''forward'' method; the thermal field is calculated based on selected initial conditions and boundary conditions such as temperature and permeability distributions. If the calculated thermal field matches the data, the chosen conditions are inferred to be possibly correct. Because many sets of initial conditions may produce similar thermal fields, users of the ''forward'' method may inadvertently miss the correct set of initial conditions. Analytical methods for ''inverting'' data allow the determination of all the possible solutions consistent with the definition of the problem. In this paper the authors suggest an approach for inverting thermal data from a hydrothermal system, and compare it to the more conventional approach. The authors illustrate the difference in the methods by comparing their application to the Salton Sea Geothermal Field by Lau (1980a) and Kasameyer, et al. (1984). In this particular example, the inverse method was used to draw conclusions about the age and total rate of fluid flow into …

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

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