31 Matching Results

Search Results

Advanced search parameters have been applied.

Coal log pipeline research at University of Missouri. 3rd quarterly report for 1995, July 1, 1995--September 30, 1995

Description: During this quarter (1/1/95-9/30/95), major progress has been made in the following areas of coal log pipeline research, development and technology transfer: (1) Conceptual design of a test machine based on hydraulic presses to mass-produce 5.4-inch-diameter coal logs for testing in a 6-inch-diameter pipeline has been completed. (2) Conceptual design of a rotary-press machine to produce 1.9-inch-diameter coal logs for testing in a 2-inch-diameter pipeline has also been completed. (3) It has been confirmed through experiments that molds with round-edge exit can make logs as good as those made with tapered exit. (4) Conducted a study to determine the effect of surface condition of mold and lubricants on the quality of coal logs. (5) Completed an evaluation of the effect of fiber (wood pulp) on coal log quality. (6) Prepared an apparatus for testing fast compaction of coal logs -- 2 second per log. (7) Compacted coal logs in a 5.3-inch-diameter mold. (8) Completed a preliminary study to assess vacuum and steam heating systems to enhance coal log production and quality. (9) Changed the small-scale-CLP-demo loop from a once-through system to a recirculating system. (10) Completed revision of CLP economic model and revised the 1993 report.
Date: December 31, 1995
Creator: Liu, H.
Partner: UNT Libraries Government Documents Department

A brief review of bacterial transport in natural porous media

Description: This report reviews advances in the descriptions of microbial transport processes. The advances can often be translated into technological advances for solute transport, with potential applicability to a number of subsurface concerns related to solutes. The processes involved in microbial transport include physically controlled processes, chemically controlled processes, and biologically controlled processes. The physical processes involved in the transport of microbes include advection, diffusion, dispersion, straining, filtration, and exclusion. Biomass removal by chemical reactions has received less attention, and included electrostatic attraction and hydrophobic sorption. In addition, microbiologic processes affecting the fate and transport of microbes in the subsurface include growth and decay; motility and chemotaxis; biological adhesion; and predation. Interdependencies among these processes arise through coupling, e.g., as multiscale mixing in heterogeneous environments affects nutrient availability (growth) and filtration velocities (attachment).
Date: December 1, 1995
Creator: Ginn, T.R.
Partner: UNT Libraries Government Documents Department

Baseline risk assessment of ground water contamination at the uranium mill tailings site near Lakeview, Oregon. Revision 1

Description: Surface cleanup at the Uranium Mill Tailings Remedial Action (UMTRA) Project site near Lakeview, Oregon was completed in 1989. The Ground Water Project evaluates the nature and extent of ground water contamination that resulted from the uranium ore processing activities. The Ground Water Project is in its beginning stages. Human health may be at risk from exposure to ground water contaminated by uranium ore processing. Exposure could occur by drinking water pumped out of a hypothetical well drilled in the contaminated areas. Ecological risks to plants or animals may result from exposure to surface water and sediment that have received contaminated ground water. A risk assessment describes a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the ecological environment may be exposed, and the health or ecological effects that could result from that exposure. This risk assessment is a site-specific document that will be used to evaluate current and potential future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will determine whether any action is needed to protect human health or the ecological environment.
Date: December 1, 1995
Partner: UNT Libraries Government Documents Department

Simulation and analysis of the plutonium shipping container subject to 30-foot drops

Description: The shipping container 5320 is a shipping package for radioactive materials. In order to maintain the component in this packaging within the sub-critical state when subjected to any kind of Hypothetical Accident conditions (HAC), this Type B packaging is designed with various impact limiters. The present study is to examine the energy absorbing capacity of the impact limiter design of this container subjected to a 30-foot drop onto a flat unyielding horizontal surface in each of the three critical dropping orientations. This paper presents the results of a three dimensional nonlinear dynamic impact analysis. This analysis shows the deformed configuration of the container caused by the impact and also determines the effects of different stress wave paths in three distinct drops on the stress states in the critical component. The solution to the problem was obtained using the ABAQUS (explicit) finite element computer code. The nonlinearity of this analysis involves large structural deformation, elasto-plastic materials with strain hardening as well as multiple contact interfaces. Three drop orientations were studied, namely, top down impact, bottom down impact and side impact. Results will be compared against actual drop test data.
Date: December 31, 1995
Creator: Gong, C.; Gupta, N.K. & Gromada, R.J.
Partner: UNT Libraries Government Documents Department

Functional description for the Worldwide Port System (WPS) Regional Integrated Cargo Database (ICDB)

Description: This Functional Description for the Worldwide Port System (WPS) Regional Integrated Cargo Database (ICDB) documents the purpose of and requirements for the ICDB in order to ensure a mutual understanding between the development group and the user group of the system. This Functional Description defines ICDB and provides a clear statement of the initial operational capability to be developed.
Date: December 15, 1995
Creator: Truett, L.F.; Rollow, J.P.; Shipe, P.C.; Faby, E.Z.; Fluker, J.; Hancock, W.R. et al.
Partner: UNT Libraries Government Documents Department

Ground water flow velocity in the bank of the Columbia River, Hanford, Washington

Description: To properly characterize the transport of contaminants from the sediments beneath the Hanford Site into the Columbia River, a suite of In Situ Permeable Flow Sensors was deployed to accurately characterize the hydrologic regime in the banks of the river. The three dimensional flow velocity was recorded on an hourly basis from mid May to mid July, 1994 and for one week in September. The first data collection interval coincided with the seasonal high water level in the river while the second interval reflected conditions during relatively low seasonal river stage. Two flow sensors located approximately 50 feet from the river recorded flow directions which correlated very well with river stage, both on seasonal and diurnal time scales. During time intervals characterized by falling river stage, the flow sensors recorded flow toward the river while flow away from the river was recorded during times of rising river stage. The flow sensor near the river in the Hanford Formation recorded a component of flow oriented vertically downward, probably reflecting the details of the hydrostratigraphy in close proximity to the probe. The flow sensor near the river in the Ringold Formation recorded an upward component of flow which dominated the horizontal components most of the time. The upward flow in the Ringold probably reflects regional groundwater flow into the river. The magnitudes of the flow velocities recorded by the flow sensors were lower than expected, probably as a result of drilling induced disturbance of the hydraulic properties of the sediments around the probes. The probes were installed with resonant sonic drilling which may have compacted the sediments immediately surrounding the probes, thereby reducing the hydraulic conductivity adjacent to the probes and diverting the groundwater flow away from the sensors.
Date: December 1, 1995
Creator: Ballard, S.
Partner: UNT Libraries Government Documents Department

Nonlinear dynamics and plasma transport

Description: This progress report reports work done on a program in nonlinear dynamical aspects of plasma turbulence and transport funded by DOE from 1992-1995. The purpose of this program has been to promote the utilization of recent pathbreaking developments in nonlinear science in plasma turbulence and transport and to fully utilize the scientific expertise of Russian fusion and plasma community in collaboration with our group to address outstanding fusion theory problems. In the work reported in our progress report, we have studied simple models which are motivated by observation on actual fusion devices. The models focus on the important physical processes without incorporating the complexity of the geometry of real devices. We have also studied linear stability problems which incorporated important physics issues related to geometry involving closed field lines and open field lines. This allows for a deeper analysis and understanding of the system both analytically and numerically. The strong collaboration between the Russian visitors and the US participants has led to a fruitful and strong research program that taps the complementary analytic and numerical capabilities of the two groups. Over the years several distinguished Russian visitors have interacted with various members of the group and set up collaborative work which forms a significant part of proposed research. Dr. Galeev, Director of the Space Research Institute of Moscow and Dr. Novakovskii from the Kurchatov Institute are two such ongoing collaborations. 21 refs.
Date: December 1, 1995
Creator: Liu, C.S.; Sagdeev, R.; Antonsen, T.; Drake, J.; Hassma, A. & Guzdar, P.N.
Partner: UNT Libraries Government Documents Department

Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions. Final report, November 1995

Description: A study is described on the hydrological and geotechnical behavior of an oil shale solid waste. The objective was to obtain information which can be used to assess the environmental impacts of oil shale solid waste disposal in the Green River Basin. The spent shale used in this study was combusted by the Lurgi-Ruhrgas process by Rio Blanco Oil Shale Company, Inc. Laboratory bench-scale testing included index properties, such as grain size distribution and Atterberg limits, and tests for engineering properties including hydraulic conductivity and shear strength. Large-scale tests were conducted on model spent shale waste embankments to evaluate hydrological response, including infiltration, runoff, and seepage. Large-scale tests were conducted at a field site in western Colorado and in the Environmental Simulation Laboratory (ESL)at the University of Wyoming. The ESL tests allowed the investigators to control rainfall and temperature, providing information on the hydrological response of spent shale under simulated severe climatic conditions. All experimental methods, materials, facilities, and instrumentation are described in detail, and results are given and discussed. 34 refs.
Date: December 31, 1995
Partner: UNT Libraries Government Documents Department

Sampling results, DNAPL monitoring well GW-726, Oak Ridge Y-12 plant, Oak Ridge, Tennessee. Quarterly report, April 1, 1994--September 30, 1994.

Description: In January 1990, dense, non aqueous phase liquids (DNAPLs) were discovered at a depth of approximately 274 foot below ground surface along the southern border of the Y-12 Plant Burial Grounds. Immediately after the discovery, an investigation was conducted to assess the occurrence of DNAPL at the site and to make recommendations for further action. This report summarizes purging and sampling activities for one of these multiport wells, GW-726, and presents analytical results for GW-726.
Date: December 31, 1995
Partner: UNT Libraries Government Documents Department

A study of sediment motions and bottom layer dynamics over the Middle Atlantic Bight shelf and upper slope. Final technical report, 1 June 1992--31 May 1995

Description: A study of sediment dynamics over the Middle Atlantic Bight (MAB) in the vicinity of the Cape Hatteras Confluence (CHC), including the mouths of estuaries, the shelf and the slope, was carried out by investigators at North Carolina State University as part of the Department of Energy Ocean Margins Program. Studied were processes effecting sediment motion. In particular, the processes which determine rates of vertical transport of dissolved carbon dioxide and organic matter and particulates to and from the bottom by turbulent mixing resuspension and particulate sinking and vertical motions induced by BBL convergences; especially during periods of storm activity when both surface waves and currents are maxima.
Date: December 31, 1995
Creator: Pietrafesa, L.J.
Partner: UNT Libraries Government Documents Department

Natural convection heat transfer within horizontal spent nuclear fuel assemblies

Description: Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.
Date: December 1, 1995
Creator: Canaan, R.E.
Partner: UNT Libraries Government Documents Department

Time resolved laser studies of the proton pump mechanism of bacteriorhodopsin. Final report, April 1, 1994--March 31, 1995

Description: This report summarizes the following research: ``The pH dependence of the subpicosecond retinal photoisomerization process in bacteriorhodopsin: evidence for parallel photocycles,`` ``pH dependence of the rate and quantum yield of the retinal photoisomerization in bacteriorhodopsin,`` ``Recording of transient grating using the short lived bacteriorhodopsin photocycle intermediates,`` ``The C-terminus and the calcium low-affinity binding sites in bacteriorhodopsin,`` ``Binding of, and energy-transfer studies from retinal to organic cations in regenerated reduced bacteriorhodopsin,`` and ``Binding characteristics of an organometallic cation, Ru(bpy)32+ in regenerated bacteriorhodopsin.``
Date: December 31, 1995
Creator: El-Sayed, M.A.
Partner: UNT Libraries Government Documents Department

Petroleum supply monthly, December 1995: With data for October 1995

Description: Data presented in the Petroleum Supply Monthly (PSM) describe the supply and disposition of petroleum products in the US and major US geographic regions. The data series describe production, imports and exports, inter-Petroleum Administration for Defense (PAD) District movements, and inventories by the primary suppliers of petroleum products in the US (50 States and the District of Columbia). The reporting universe includes those petroleum sectors in primary supply. Included are: petroleum refiners, motor gasoline blenders, operators of natural gas processing plants and fractionators, inter-PAD transporters, importers, and major inventory holders of petroleum products and crude oil. When aggregated, the data reported by these sectors approximately represent the consumption of petroleum products in the US. The tables and figures in the Summary Statistics section of the PSM present a time series of selected petroleum data on a US level. The Detailed Statistics tables of the PSM present statistics for the most current month available as well as year-to-date. In most cases, the statistics are presented for several geographic areas--the US (50 States and the District of Columbia), five PAD Districts, and 12 Refining Districts. At the US and PAD District level, the total volume and the daily rate of activities are presented. 16 figs., 6 tabs.
Date: December 1, 1995
Partner: UNT Libraries Government Documents Department

Measurements of short-pulse propagation through concrete walls

Description: The authors recently performed a series of experimental measurements of transient electromagnetic (EM) propagation through two different concrete walls. Several different short-duration pulses were used for the incident radiation, with frequency content from VHF to 20 GHz. Both walls were 30 cm thick, with three internal layers of reinforcing steel bars. For this particular set of data, the incident wave polarization was vertical linear only. Corroborating swept-frequency measurements were made with a vector network analyzer. This paper describes the propagation measurements through the two walls, and the propagation model of a lossy dielectric layer. They also examine the transfer function, dielectric constant, loss tangent, attenuation constant, and time-domain impulse response of these walls. The attenuation increases steadily with frequency, and is a strong function of the moisture content of the concrete. The time-domain pulse attenuation and dispersion are consistent with the lowpass-filtering effect of this attenuation loss vs. frequency. The time domain behavior will be very useful in time-domain radar studies of ground-penetrating radar, free-space layered measurement systems, etc.
Date: December 31, 1995
Creator: Aurand, J.F.
Partner: UNT Libraries Government Documents Department

Preconceptual design of a Long-Pulse Spallation Source (LPSS) at the LANSCE Facility: Target system, facility, and material handling considerations

Description: This report provides a summary of a preconceptual design study for the proposed Long-Pulse Spallation. Source (LPSS) at the Los Alamos Neutron Science Center (LANSCE). The LPSS will use a 0.8-MW proton beam to produce neutrons from a tungsten target. This study focuses on the design of the target station and changes to the existing building that would be made to accommodate the LPSS. The LPSS will provide fifteen flight paths to neutron scattering instruments. In addition, options for generating ultracold neutrons, pions, and muons will be available. Flight-energy, forward-scattered neutrons on the downstream side of the target will also be available for autoradiography studies. A Target Test Bed (TTB) is also proposed for full-beam tests of component materials and advanced spallation neutron sources. The design allows for separation of the experiment hall from the beam line, target, and flight paths. The target and moderator systems and the systems/components to be tested in the TTB will be emplaced and removed separately by remotely operated, shielded equipment. Irradiated materials will be transported to a hot cell adjacent to the target chamber for testing by remotely operated instruments. These tests will provide information about how materials properties are affected by proton and neutron beams.
Date: December 1, 1995
Creator: Sommer, W.F.
Partner: UNT Libraries Government Documents Department

Upgraded coal interest group. Quarterly report, July 1, 1995--September 30, 1995

Description: The objectives of the Upgraded Coal Interest Group (UCIG) are as follows: Review and update the status of various coal upgrading technologies and developments and critically assess the results. Perform engineering screening analyses on various coal upgrading approaches. Perform commercialization analyses that will promote the availability and use of upgraded coal products by quantifying the benefits of using them. Identify market opportunities for introduction of upgraded coals. Perform critical analyses on a variety of coals and technologies in areas important to users but not readily available. Perform critical experiments which will show the differences between technologies.
Date: December 31, 1995
Creator: Weber, W. & Lebowitz, H.E.
Partner: UNT Libraries Government Documents Department

The effect of location and facility demand on the marginal cost of delivered wood chips from energy crops: A case study of the state of Tennessee

Description: Cost-supply curves for delivered wood chips from short rotation woody crops were calculated for 21 regularly-spaced locations spanning the state of Tennessee. These curves were used to systematically evaluate the combined effects of location and facility demand on wood chip feedstock costs in Tennessee. The cost-supply curves were developed using BRAVO, a GIS-based decision support system which calculates marginal cost of delivering wood chips to a specific location given road network maps and maps of farmgate prices and supplies of woody chips from short rotation energy crops. Marginal costs of delivered chips varied by both facility location in the state and facility demand. Marginal costs were lowest in central Tennessee unless the facility demand was greater than 2.7 million dry Mg per year (3 million dry tons per year) in which case west Tennessee was the lowest cost region. Marginal costs rose rapidly with increasing facility demand in the mountainous eastern portion of the state. Transportation costs accounted for 18 to 29% of the delivered cost and ranged between $8 and $18/dry Mg ($7 and $16/dry ton). Reducing the expected farmer participation rate from 100% to 50% or 25% dramatically raised the marginal costs of feedstock supply in the east and central regions of the state. The analysis demonstrates the need to use geographically-specific information when projecting the potential costs and supplies of biomass feedstock.
Date: December 31, 1995
Creator: Graham, R.L.; Liu, W.; Downing, M.; Noon, C.; Daly, M. & Moore, A.
Partner: UNT Libraries Government Documents Department

Gas intrusion into SPR caverns

Description: The conditions and occurrence of gas in crude oil stored in Strategic Petroleum Reserve, SPR, caverns is characterized in this report. Many caverns in the SPR show that gas has intruded into the oil from the surrounding salt dome. Historical evidence and the analyses presented here suggest that gas will continue to intrude into many SPR caverns in the future. In considering why only some caverns contain gas, it is concluded that the naturally occurring spatial variability in salt permeability can explain the range of gas content measured in SPR caverns. Further, it is not possible to make a one-to-one correlation between specific geologic phenomena and the occurrence of gas in salt caverns. However, gas is concluded to be petrogenic in origin. Consequently, attempts have been made to associate the occurrence of gas with salt inhomogeneities including anomalies and other structural features. Two scenarios for actual gas intrusion into caverns were investigated for consistency with existing information. These scenarios are gas release during leaching and gas permeation through salt. Of these mechanisms, the greater consistency comes from the belief that gas permeates to caverns through the salt. A review of historical operating data for five Bryan Mound caverns loosely supports the hypothesis that higher operating pressures reduce gas intrusion into caverns. This conclusion supports a permeability intrusion mechanism. Further, it provides justification for operating the caverns near maximum operating pressure to minimize gas intrusion. Historical gas intrusion rates and estimates of future gas intrusion are given for all caverns.
Date: December 1, 1995
Creator: Hinkebein, T.E.; Bauer, S.J.; Ehgartner, B.L.; Linn, J.K.; Neal, J.T.; Todd, J.L. et al.
Partner: UNT Libraries Government Documents Department

Cassini RTG Program. Monthly technical progress report, October 30--November 26, 1995

Description: The technical progress achieved during the period 30 October through 26 November, 1995 is described herein. This report is organized by program task structure: (1) spacecraft integration and liaison; (2) engineering support; (3) safety; (4) qualified unicouple production; (5) ETG fabrication, assembly, and test; (6) ground support equipment (GSE); (7) RTG shipping and launch support; (8) designs, reviews, and mission applications; (9) project management, quality assurance, reliability, contract changes, CAGO acquisition (operating funds), and GACO maintenance and repair; and CAGO acquisition (capital funds).
Date: December 24, 1995
Partner: UNT Libraries Government Documents Department

Agreement between the Regents of the University of California (Los Alamos National Laboratory (LANL)) and the A.V. Topchiev Institute of Petrochemical Synthesis (TIPS), the Russian Academy of Sciences, Number 8992Q0004-35. Final report, Task order 001: Subprogram PTMSP and Subprogram Predictions.

Description: In order to develop the conditions for preparing polymers with different molecular masses, the authors continued their investigation of TMSP (1-(trimethylsilyl)-1-propyne) polymerization catalyzed by TaCl{sub 5} and TaCl{sub 5}/BuLi at various ratios of VTMS (regulator of molecular mass of the polymer) : catalyst. They also studied the effect of the structure of silahydrocarbon on the process of TMSP polymerization. To this end, they carried out polymerization of TMSP in the presence of additives of vinylphenyldimethylsilane and vinylallyldimethylsilane. The conditions of experiments and the results obtained are shown. The method for controlling the molecular mass of PTMSP makes it possible to prepare PTMSP suitable for manufacture of both flat membranes and hollow fibers. The paper also describes the experimental study of PTMSP gas permeability, gas sorption in PTMSP, and a computer program for the prediction of all gas permeability parameters of polymers.
Date: December 31, 1995
Partner: UNT Libraries Government Documents Department

Finding of no significant impact: Interim storage of enriched uranium above the maximum historical level at the Y-12 Plant Oak Ridge, Tennessee

Description: The US Department of Energy (DOE) has prepared an Environmental Assessment (EA) for the Proposed Interim Storage of Enriched Uranium Above the Maximum Historical Storage Level at the Y-12 Plant, Oak Ridge, Tennessee (DOE/EA-0929, September, 1994). The EA evaluates the environmental effects of transportation, prestorage processing, and interim storage of bounding quantities of enriched uranium at the Y-12 Plant over a ten-year period. The State of Tennessee and the public participated in public meetings and workshops which were held after a predecisional draft EA was released in February 1994, and after the revised pre-approval EA was issued in September 1994. Comments provided by the State and public have been carefully considered by the Department. As a result of this public process, the Department has determined that the Y-12 Plant-would store no more than 500 metric tons of highly enriched uranium (HEU) and no more than 6 metric tons of low enriched uranium (LEU). The bounding storage quantities analyzed in the pre-approval EA are 500 metric tons of HEU and 7,105.9 metric tons of LEU. Based on-the analyses in the EA, as revised by the attachment to the Finding of No Significant Impact (FONSI), DOE has determined that interim storage of 500 metric tons of HEU and 6 metric tons of LEU at the Y-12 Plant does not constitute a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, an Environmental Impact Statement (EIS) is not required and the Department is issuing this FONSI.
Date: December 1, 1995
Partner: UNT Libraries Government Documents Department

Analysis of radiation measurement data of the BUSS cask

Description: The Beneficial Uses Shipping System (BUSS) is a Type-B packaging developed for shipping nonfissile, special-form radioactive materials to facilities such as sewage, food, and medical-product irradiators. The primary purpose of the BUSS cask is to provide shielding and confinement, as well as impact, puncture, and thermal protection for its certified special-form contents under both normal transport and hypothetical accident conditions. A BUSS cask that contained 16 CsCl capsules (2.723 {times} 10{sup 4} TBq total activity) was recently subjected to radiation survey measurements at a Westinghouse Hanford facility, which provided data that could be used to validate computer codes. Two shielding analysis codes, MICROSHIELD (User`s Manual 1988) and SAS4 (Tan 1993), that are used at Argonne National Laboratory to evaluate the safety of packaging of radioactive materials during transportation, have been selected for analysis of radiation data obtained from the BUSS cask. MICROSHIELD, which performs only gamma radiation shielding calculation, is based on a point-kernel model with idealized geometry, whereas SAS4 is a control module in the SCALE code system (1995) that can perform three-dimensional Monte Carlo shielding calculation for photons and neutrons, with built-in procedures for cross-section data processing and automated variance reduction. The two codes differ in how they model the details of the physics of gamma photon attenuation in materials, and this difference is reflected in the associated engineering cost of the analysis. One purpose of the analysis presented in this paper, therefore, is to examine the effects of the major modeling assumptions in the two codes on calculated dose rates, and to use the measured dose rates for comparison. The focus in this paper is on analysis of radiation dose rates measured on the general body of the cask and away from penetrations.
Date: December 31, 1995
Creator: Liu, Y.Y. & Tang, J.S.
Partner: UNT Libraries Government Documents Department