Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO: (1) identified census tracts in medium-sized to large cities that met specific poverty criteria; and (2) provided additional information on each census tract."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO updated its previous report on United Nations (U.N.) financial issues and U.S. arrears, focusing on: (1) the amount the United States will need to pay before the end of 1999 to avoid losing its right to vote in the U.N. General Assembly; (2) the trend in U.S. assessed contributions and arrears that has led to the current situation; (3) U.S. arrears and the amounts withheld for legislative and policy reasons; and (4) the status of member states that lost their right to vote in the General Assembly at the beginning of 1999."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Department of Education's method of calculating a school's student loan default rate, focusing on: (1) whether there has been an increase in the number of borrowers who entered repayment but subsequently received deferments or forbearances; (2) what effect would excluding borrowers whose loans were in deferment or forbearance have on the most recent default rate calculation; and (3) whether additional schools would have exceeded the 25-percent default rate threshold under the alternative method of calculating the default rate."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on: (1) how changes in the way airlines sell tickets affected travel agencies and consumers; (2) airlines' policies and practices for the sale and use of airline tickets sold by travel agencies compared with the sale and use of tickets sold directly by airlines; (3) what airlines' policies and practices are for making their airfares, particularly discount fares, accessible to travel agencies and consumers; and (4) what airlines' policies and practices are regarding the use of data on travel agency sales."

Weekly newspaper from Mannford, Oklahoma that includes local, state, and national news along with advertising.

Weekly newspaper from Mannford, Oklahoma that includes local, state, and national news along with advertising.

Weekly newspaper from Wylie, Texas that includes local, state and national news along with advertising.

Semi-weekly newspaper from Clifton, Texas that includes local, state, and national news along with advertising.

Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with advertising.

Postulated accidental release of radiological material to surface water bodies on the Savannah River Site and the resulting downstream contamination of the Savannah River pose a potential threat to downstream river users.

We examined the ability of a halophilic bacterium (WFP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell Surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited volubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellulary as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis, of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids …

Overall transfer factors for major ingestion pathways are derived for plutonium and americium. These transfer factors relate the radionuclide concentration in a given foodstuff to deposition on the soil. Equations describing basic relationships consistent with Regulatory Guide 1.109 are followed. Updated values and coefficients from IAEA Technical Reports Series No. 364 are used when a available. Preference is given to using factors specific to the Savannah River Site.

This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media. The code is designed specifically to handle complex multi-layer and/or heterogeneous aquifer systems in an efficient manner and accommodates a wide range of boundary conditions. Additionally, 1-D and 2-D (in Cartesian coordinates) problems are handled in FACT by simply limiting the number of elements in a particular direction(s) to one. The governing equations in FACT are formulated only in Cartesian coordinates.

Air samples from F-Canyon effluents were collected at the F-Canyon stack and transported to a laboratory at the Savannah River Technology Center (SRTC) for analysis using a Fourier transform infrared spectrometer in conjunction with a multipath cell. Air samples were collected during the decladding and acid cuts of the dissolution of the irradiated aluminum-cladded slugs. The FTIR analyses of the air samples show the presence of NO2, NO, HNO2, N2O, SF6, and 85Kr during the dissolution cycle. The concentration time profiles of these effluents corresponded with expected release rates from the F-Canyon operations.

The joint USNRC/CEC consequence uncertainty study was chartered after the development of two new probabilistic accident consequence codes, MACCS in the U.S. and COSYMA in Europe. Both the USNRC and CEC had a vested interest in expanding the knowledge base of the uncertainty associated with consequence modeling, and teamed up to co-sponsor a consequence uncertainty study. The information acquired from the study was expected to provide understanding of the strengths and weaknesses of current models as well as a basis for direction of future research. This paper looks at the elicitation process implemented in the joint study and discusses some of the uncertainty distributions provided by eight panels of experts from the U.S. and Europe that were convened to provide responses to the elicitation. The phenomenological areas addressed by the expert panels include atmospheric dispersion and deposition, deposited material and external doses, food chain, early health effects, late health effects and internal dosimetry.

Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, they used FIB technology to prepare an IC for inspection of voided metal interconnects (lines) and vias. Conventional FIB milling was combined with a super-enhanced gas assisted milling process that uses XeF{sub 2} for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of Ml lines simultaneously, enabling rapid localization and plan view imaging of voids in lines and vias with backscattered electron (BSE) imaging in a scanning electron microscopy (SEM). Sequential cross sections of individual voided vias enabled them to develop a 3-d reconstruction of these voids. This information clarified how the voids were formed, helping to identify the IC process steps that needed to …

Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, we used FIB technology to prepare an IC for inspection of voided metal interconnects (''lines'') and vias. Conventional FIB milling was combined with a super-enhanced gas assisted milling process that uses XeF{sub 2} for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of Ml lines simultaneously, enabling rapid localization and plan view imaging of voids in lines and vias with backscattered electron (BSE) imaging in a scanning electron microscope (SEM). Sequential cross sections of individual voided vias enabled us to develop a 3-d reconstruction of these voids. This information clarified how the voids were formed, helping us identify the IC process steps that needed to …

The understanding and manipulation of the point defect structure in oxide glasses have been critical to the enhanced performance and reliability of optical-fiber-based, photosensitive photonic devices that currently found widespread application in telecommunications and remote sensing technologies. We provide a brief review of past research investigating photosensitive mechanisms in germanosilicate glasses, the primary material system used in telecommunications fibers. This discussion motivates an overview of ongoing work within our laboratories to migrate photosensitive glass technologies to a planar format for integrated photonic applications. Using reactive-atmosphere, RF-magnetron sputtering, we have demonstrated control of glass defect structure during synthesis, thereby controlling both the material photosensitivity (i. e. dispersion and magnitude of the refractive index change) and its environmental stability.

The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

As part of a collaborative effort between Sandia National Laboratories and the University of Kentucky to develop a deployable mirror for remote sensing applications, research in shape sensing and control algorithms that leverage the distributed nature of electron gun excitation for piezoelectric bimorph mirrors is summarized. A coarse shape sensing technique is developed that uses reflected light rays from the sample surface to provide discrete slope measurements. Estimates of surface profiles are obtained with a cubic spline curve fitting algorithm. Experiments on a PZT bimorph illustrate appropriate deformation trends as a function of excitation voltage. A parallel effort to effect desired shape changes through electron gun excitation is also summarized. A one dimensional model-based algorithm is developed to correct profile errors in bimorph beams. A more useful two dimensional algorithm is also developed that relies on measured voltage-curvature sensitivities to provide corrective excitation profiles for the top and bottom surfaces of bimorph plates. The two algorithms are illustrated using finite element models of PZT bimorph structures subjected to arbitrary disturbances. Corrective excitation profiles that yield desired parabolic forms are computed, and are shown to provide the necessary corrective action.

Consider the 2-matching problem defined on the complete graph, with edge costs which satisfy the triangle inequality. We prove that the value of a minimum cost 2-matching is bounded above by 4/3 times the value of its linear programming relaxation, the fractional 2-matching problem. This lends credibility to a long-standing conjecture that the optimal value for the traveling salesman problem is bounded above by 4/3 times the value of its linear programming relaxation, the subtour elimination problem.

This report summarizes the performance of the Sanitary Landfill Supplemental Test data, an evaluation of applicability, conclusions, recommendations, and related information for implementation of this remediation technology at the SRS Sanitary Landfill.

Electret ion chambers are inexpensive, light-weight, robust, commercially available, passive charge-integrating devices for accurate measurement of different radiations.

A capacitated covering IP is an integer program of the form min{l_brace}ex{vert_bar}Ux {ge} d, 0 {le} x {le} b, x {element_of} Z{sup +}{r_brace}, where all entries of c, U, and d are nonnegative. Given such a formulation, the ratio between the optimal integer solution and the optimal solution to the linear program relaxation can be as bad as {parallel}d{parallel}{sub {proportional_to}}, even when U consists of a single row. They show that by adding additional inequalities, this ratio can be improved significantly. In the general case, they show that the improved ratio is bounded by the maximum number of non-zero coefficients in a row of U, and provide a polynomial-time approximation algorithm to achieve this bound. This improves upon the results of Bertsimas and Vohra, strengthening their extension of Hall and Hochbaum.