The authors develop and evaluate a modified invasion percolation (MIP) model for quasi-static immiscible displacement in horizontal fractures. The effects of contact angle, local aperture field geometry, and local in-plane interracial curvature between phases are included in the calculation of invasion pressure for individual sites in a discretized aperture field. This pressure controls the choice of which site is invaded during the displacement process and hence the growth of phase saturation structure within the fracture. To focus on the influence of local in-plane curvature on phase invasion structure, they formulate a simplified nondimensional pressure equation containing a dimensionless curvature number (C) that weighs the relative importance of in-plane curvature and aperture-induced curvature. Through systematic variation of C, they find in-plane interracial curvature to greatly affect the phase invasion structure. As C is increased from zero, phase invasion fronts transition from highly complicated (IP results) to microscopically smooth. In addition, measurements of fracture phase saturations and entrapped cluster statistics (number, maximum size, structural complication) show differential response between wetting and nonwetting invasion with respect to C that is independent of contact angle hysteresis. Comparison to experimental data available at this time substantiates predicted behavior.

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the Department of Energy's (DOE) decision to select a commercial reactor for the production of tritium and to designate an accelerator to function as a backup, focusing on: (1) whether the cost estimates used by the Secretary of Energy during the process of selecting between the tritium production technology options were comparable and adequately supported; (2) what management, technological, and legal activities could affect the completion of the commercial reactor option on schedule and within budget; and (3) whether DOE's current plan for the development and design of the accelerator option is an effective backup that DOE could construct and operate within cost and schedule estimates."

A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.

The Lasentec M600 in-line particle size analyzer was installed at Oak Ridge National Laboratory (ORNL) in August 1998 to support retrieval of the Gunite and Associated Tanks (GAAT). Before installation at ORNL, the sensor underwent validation testing at the Pacific Northwest National Laboratory (PNNL) Instrument Validation facility. Mechanically, the instrument worked well during validation testing and met all expectations. Operationally, much was learned about optimum ways to display and interpret the data. Slurry samples taken during the in-line tests at PNNL were shipped to the vendor for analysis with a benchtop Lasentec sensor. These experiments were performed to determine if off-line analyses yield particle size distributions similar to those generated by the in-line sensor. It was determined that the Lasentec sensor measures repeatable chord lengths as long as particles are ''presenter'' to the sensor window the same way. After the initial non-radioactive simulant testing at PNNL, the instrument was shipped for radioactive validation and acceptance testing in the Slurry Monitoring Test System (SMTS) connected to the Tank W-9 of the GAATs at ORNL. For all acceptance tests conducted at ORNL, the variation in the chord length distribution and the total particle count corresponded very well with the slurry density data …

Fracture transmissivity and detailed aperture fields are measured in analog fractures specially designed to evaluate the utility of the Reynolds equation. The authors employ a light transmission technique with well-defined accuracy ({approximately}1% error) to measure aperture fields at high spatial resolution ({approximately}0.015 cm). A Hele-Shaw cell is used to confirm the approach by demonstrating agreement between experimental transmissivity, simulated transmissivity on the measured aperture field, and the parallel plate law. In the two rough-walled analog fractures considered, the discrepancy between the experimental and numerical estimates of fracture transmissivity was sufficiently large ({approximately} 22--47%) to exclude numerical and experimental errors (< 2%)as a source. They conclude that the three-dimensional character of the flow field is important for fully describing fluid flow in the two rough-walled fractures considered, and that the approach of depth averaging inherent in the formulation of the Reynolds equation is inadequate. They also explore the effects of spatial resolution, aperture measurement technique, and alternative definitions for link transmissivities in the finite-difference formulation, including some that contain corrections for tortuosity perpendicular to the mean fracture plane and Stokes flow. Various formulations for link transmissivity are shown to converge at high resolution ({approximately} 1/5 the spatial correlation length) in the …

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO analyzed the costs of operating five Superfund cleanup sites, focusing on: (1) what portion of the total funds the Environmental Protection Agency (EPA) spent on each site was used to pay contractors for remedial actions as opposed to other activities and how the contractors spent these funds; and (2) whether the actual cost for remedial actions differed from the estimated costs and if so, why."

Document issued by the Open Records Division at the Office of the Attorney General of Texas in Austin, Texas, providing an informal interpretation of Texas law related to a series of written requests for access to all memoranda, letters, reports, directives, e-mail, telephone message slips, etc to the Denton County Judge Kirk Wilson.

Document issued by the Open Records Division at the Office of the Attorney General of Texas in Austin, Texas, providing an informal interpretation of Texas law related to whether the Texas Department of Agriculture can withhold documents related to an incident that is being sought for the purpose of bringing a lawsuit against the department.

Document issued by the Open Records Division at the Office of the Attorney General of Texas in Austin, Texas, providing an informal interpretation of Texas law related to whether the Tarrant County Sheriff's Department must release offense reports related to pending litigation.

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 letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Department of Defense's (DOD) use of "radiation dose reconstruction" as a tool for determining veterans' eligibility for benefits, focusing on: (1) studies that assessed the validity of dose reconstruction for estimating veterans' radiation exposure and discussing the issue with experts in the field and other knowledgeable individuals; (2) what activities are in place to oversee the dose reconstruction process; and (3) alternatives for deciding veterans' claims for compensation related to radiation exposure."

Materials for neutron absorber, thermal shunt, and fill gas for use in the waste package were selected using a qualitative approach. For each component, selection criteria were identified; candidate materials were selected; and candidates were evaluated against these criteria. The neutron absorber materials evaluated were essentially boron-containing stainless steels. Two candidates were evaluated for the thermal shunt material. The fill gas candidates were common gases such as helium, argon, nitrogen, carbon dioxide, and dry air. Based on the performance of each candidate against the criteria, the following selections were made: Neutron absorber--Neutronit A978; Thermal shunt--Aluminum 6061 or 6063; and Fill gas--Helium.