Chemical Technology Division annual report, 1999. (open access)

Chemical Technology Division annual report, 1999.

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Date: July 17, 2000
Creator: Lewis, D.; Miller, J. F.; Einziger, R. E.; Gay, E. C. & Green, D. W.
Object Type: Report
System: The UNT Digital Library
3-D Numerical Modeling of a Complex Salt Structure (open access)

3-D Numerical Modeling of a Complex Salt Structure

Reliably processing, imaging, and interpreting seismic data from areas with complicated structures, such as sub-salt, requires a thorough understanding of elastic as well as acoustic wave propagation. Elastic numerical modeling is an essential tool to develop that understanding. While 2-D elastic modeling is in common use, 3-D elastic modeling has been too computationally intensive to be used routinely. Recent advances in computing hardware, including commodity-based hardware, have substantially reduced computing costs. These advances are making 3-D elastic numerical modeling more feasible. A series of example 3-D elastic calculations were performed using a complicated structure, the SEG/EAGE salt structure. The synthetic traces show that the effects of shear wave propagation can be important for imaging and interpretation of images, and also for AVO and other applications that rely on trace amplitudes. Additional calculations are needed to better identify and understand the complex wave propagation effects produced in complicated structures, such as the SEG/EAGE salt structure.
Date: February 17, 2000
Creator: House, L.; Larsen, S. & Bednar, J. B.
Object Type: Article
System: The UNT Digital Library
Wetlands Regulation and the Law of Property Rights "Takings" (open access)

Wetlands Regulation and the Law of Property Rights "Takings"

When a wetland owner is denied permission to develop, or offered a permit with very burdensome conditions, the property's value may drop substantially. Wetlands programs also may impose costly development delays. For these reasons, federal and state wetlands regulation continues to generate "takings" lawsuits by land owners. Such suits allege that by narrowing or eliminating the economic uses to which a wetland can be put, the government has "taken" (permanently or temporarily) the wetland under the Fifth Amendment Takings Clause.
Date: February 17, 2000
Creator: Meltz, Robert
Object Type: Report
System: The UNT Digital Library
Submicron X-ray diffraction (open access)

Submicron X-ray diffraction

At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.
Date: August 17, 2000
Creator: MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter et al.
Object Type: Article
System: The UNT Digital Library
Groundwater monitoring plan for the Hanford Site 200 Area Treated Effluent Disposal Facility (open access)

Groundwater monitoring plan for the Hanford Site 200 Area Treated Effluent Disposal Facility

Seven years of groundwater monitoring at the 200 Area Treated Effluent Disposal Facility (TEDF) have shown that the uppermost aquifer beneath the facility is unaffected by TEDF effluent. Effluent discharges have been well below permitted and expected volumes. Groundwater mounding from TEDF operations predicted by various models has not been observed, and waterlevels in TEDF wells have continued declining with the dissipation of the nearby B Pond System groundwater mound. Analytical results for constituents with enforcement limits indicate that concentrations of all these are below Practical Quantitation Limits, and some have produced no detections. Likewise, other constituents on the permit-required list have produced results that are mostly below sitewide background. Comprehensive geochemical analyses of groundwater from TEDF wells has shown that most constituents are below background levels as calculated by two Hanford Site-wide studies. Additionally, major ion proportions and anomalously low tritium activities suggest that groundwater in the aquifer beneath the TEDF has been sequestered from influences of adjoining portions of the aquifer and any discharge activities. This inference is supported by recent hydrogeologic investigations which indicate an extremely slow rate of groundwater movement beneath the TEDF. Detailed evaluation of TEDF-area hydrogeology and groundwater geochemistry indicate that additional points of …
Date: May 17, 2000
Creator: Barnett, DB
Object Type: Report
System: The UNT Digital Library