Social security in a Soviet America

https://stars.library.ucf.edu/prism/1115/thumbnail.jp

Helen K. Amter to Mr. Meredith (1 October 1962)

https://egrove.olemiss.edu/mercorr_pro/1313/thumbnail.jp

Effect of a low-permeability layer on calculated gas flow at Yucca Mountain

Yucca Mountain is being studied to determine its suitability as a location for a high-level nuclear waste repository. Amter and Ross developed a model called TGIF (Topographic Induced Flow) to simulate gas flow under Yucca Mountain. The TGIF model differs significantly from previous gas flow models. It uses a governing equation that is based on the concept of freshwater head, thus avoiding the numerical problems associated with the near-cancellation of the forces due to gravity and the pressure gradient. Unlike most other models, dipping, layered media can be simulated. This paper describes a systematic sensitivity study that was designed to test several aspects of the TGIF model when used to simulate gas flow under Yucca Mountain. Values of three important inputs to the model were systematically varied to form a matrix of 80 runs. The matrix consisted of five values of permeability contrast between a bedded tuff layer and surrounding welded units (in all cases, bulk permeabilities were used to represent the combined effect of both fractures and matrix permeability), four temperature profiles representing different stages of repository cooldown, and four finite-difference grids

Injection/recovery lysimeter technique for unsaturated zone soil-water extraction

Current methods of vacuum lysimetry only allow water samples to be collected from the unsaturated zone in relatively wet soils. This thesis presents the results of computer simulation and field testing of a promising new technique that allows water samples to be collected regardless of antecedent moisture content. Injection of a chemically neutral fluid will increase the moisture content of a relatively dry soil, allowing the collection of a sample that contains soil water diluted in the injection fluid. This can be analyzed to yield qualitative chemical data. Although injection was found to alter soil structure and soil-water chemistry in some instances, the technique can be used in existing lysimeters, without modification, to repeatedly obtain partially representative soil-water samples containing inorganic and organic compounds. Injection lysimetry is best suited to those applications, such as tracer tests and detection of containment leakage, where absolute chemical concentrations are not required.hydrology collectio

Numerical studies of rock-gas flow in Yucca Mountain; Yucca Mountain Site Characterization Project

A computer model (TGIF -- Thermal Gradient Induced Flow) of two-dimensional, steady-state rock-gas flow driven by temperature and humidity differences is described. The model solves for the ``fresh-water head,`` a concept that has been used in models of variable-density water flow but has not previously been applied to gas flow. With this approach, the model can accurately simulate the flows driven by small differences in temperature. The unsaturated tuffs of Yucca Mountain, Nevada, are being studied as a potential site for a repository for high-level nuclear waste. Using the TGIF model, preliminary calculations of rock-gas flow in Yucca Mountain are made for four east-west cross-sections through the mountain. Calculations are made for three repository temperatures and for several assumptions about a possible semi-confining layer above the repository. The gas-flow simulations are then used to calculate travel-time distributions for air and for radioactive carbon-14 dioxide from the repository to the ground surface