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 Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents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.

A Tektronix-31 (Tektronix Inc. Beaverton, Oregon) desk top calculator program, which is used as a backup to the PDP-8/I computer program, is described. The program yields interplanar (d) spacings and (2theta) angle values from measurements made on an x-ray diffraction film of a powdered sample of a crystalline material. Use of the calculator provides accurate computations in a relatively rapid time interval when the PDP-8/I is not functioning because of downtime for repairs, maintenance, etc.

Concepts of the range of investigation of a borehole gravimeter are reviewed. It is shown that the maximum sensitivity to a mass point at a horizontal distance R from a borehole occurs at a vertical distance Z = R/..sqrt..2. Thus, the angle of maximum sensitivity is about 55/sup 0/ from the vertical. It is also shown that the absolute value of the gravitational effect decreases with increasing R. There are two maxima of the vertical gradient of gravity (at Z = 0 and at Z = ..sqrt../sup 3///sub 2/ R). The minimum distance required between gravimeter stations to obtain a usable measurement can be determined. The slab radius R for which the gravitational effect of a horizontal slab is equal to 45%, 90%, etc., of that of an infinite horizontal slab is a function of the measurement spacing. The closer the measurement spacing, the more information obtained.

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The principal aim of the National Waste Terminal Storage (NWTS) program is to develop repositories in several different rock formations in various parts of the country. Rocks such as salt, shale, limestone, and granite may qualify as host media for the disposition of radioactive wastes in the proper environments. In general, the only requirement for any rock formation or storage area is that it be able to contain any emplaced wastes for so long as it takes for the radioactive materials to decay to innocuous levels. This requirement, though, is a formidable one because some of the wastes will remain active for periods of hundreds of thousands of years and because the physical and chemical properties of rocks that govern circulating ground water and, hence, the containment may be difficult to determine and define. Rock salt has long been regarded as the most favored geologic medium for the containment of radioactive wastes in the United States. This stems largely from the plastic behavior of salt, which promotes self-healing and otherwise makes it impermeable to circulating ground water. Other important advantages of salt include its wide distribution, ease of mining, and favorable heat dissipation characteristics. In addition to the salt domes …

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