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A semi-analytical method for heat sweep calculations in fractured reservoirs

Description: An analytical approximation is developed for purely conductive heat transfer from impermeable blocks of rock to fluids sweeping past the rocks in fractures. The method was incorporated into a multi-phase fluid and heat flow simulator. Comparison with exact analytical solutions and with simulations using a multiple interacting continua approach shows very good accuracy, with no increase in computing time compared to porous medium simulations. 14 refs., 3 figs., 5 tabs.
Date: January 1, 1988
Creator: Pruess, K. & Wu, Y.S.
Partner: UNT Libraries Government Documents Department

UZ Flow Models and Submodels

Description: The purpose of this report is to document the unsaturated zone (UZ) flow models and submodels, as well as the flow fields that have been generated using the UZ flow model(s) of Yucca Mountain, Nevada. In this report, the term ''UZ model'' refers to the UZ flow model and the several submodels, which include tracer transport, temperature or ambient geothermal, pneumatic or gas flow, and geochemistry (chloride, calcite, and strontium) submodels. The term UZ flow model refers to the three-dimensional models used for calibration and simulation of UZ flow fields. This work was planned in the ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.7). The table of included Features, Events, and Processes (FEPs), Table 6.2-11, is different from the list of included FEPs assigned to this report in the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Table 2.1.5-1), as discussed in Section 6.2.6. The UZ model has revised, updated, and enhanced the previous UZ model (BSC 2001 [DIRS 158726]) by incorporating the repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates, and their spatial distributions as well as moisture conditions in the UZ system. These three-dimensional UZ flow fields are used directly by Total System Performance Assessment (TSPA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test hypotheses of flow and transport at different scales, and predict flow and transport behavior under a variety of climatic conditions. In addition, the limitations of the UZ model are discussed in Section 8.11.
Date: November 1, 2004
Creator: Wu, Y.
Partner: UNT Libraries Government Documents Department

MOUNTAIN-SCALE COUPLED PROCESSES (TH/THC/THM)MODELS

Description: This report documents the development and validation of the mountain-scale thermal-hydrologic (TH), thermal-hydrologic-chemical (THC), and thermal-hydrologic-mechanical (THM) models. These models provide technical support for screening of features, events, and processes (FEPs) related to the effects of coupled TH/THC/THM processes on mountain-scale unsaturated zone (UZ) and saturated zone (SZ) flow at Yucca Mountain, Nevada (BSC 2005 [DIRS 174842], Section 2.1.1.1). The purpose and validation criteria for these models are specified in ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Drift-Scale Abstraction) Model Report Integration'' (BSC 2005 [DIRS 174842]). Model results are used to support exclusion of certain FEPs from the total system performance assessment for the license application (TSPA-LA) model on the basis of low consequence, consistent with the requirements of 10 CFR 63.342 [DIRS 173273]. Outputs from this report are not direct feeds to the TSPA-LA. All the FEPs related to the effects of coupled TH/THC/THM processes on mountain-scale UZ and SZ flow are discussed in Sections 6 and 7 of this report. The mountain-scale coupled TH/THC/THM processes models numerically simulate the impact of nuclear waste heat release on the natural hydrogeological system, including a representation of heat-driven processes occurring in the far field. The mountain-scale TH simulations provide predictions for thermally affected liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature (together called the flow fields). The main focus of the TH model is to predict the changes in water flux driven by evaporation/condensation processes, and drainage between drifts. The TH model captures mountain-scale three-dimensional flow effects, including lateral diversion and mountain-scale flow patterns. The mountain-scale THC model evaluates TH effects on water and gas chemistry, mineral dissolution/precipitation, and the resulting impact to UZ hydrologic properties, flow and transport. The mountain-scale THM model addresses changes in permeability due to ...
Date: August 24, 2005
Creator: Wu, Y.S.
Partner: UNT Libraries Government Documents Department

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media

Description: Modeling fracture-matrix interaction within a complex multiple phase flow system is a key issue for fractured reservoir simulation. Commonly used mathematical models for dealing with such interactions employ a dual- or multiple-continuum concept, in which fractures and matrix are represented as overlapping, different, but interconnected continua, described by parallel sets of conservation equations. The conventional single-point upstream weighting scheme, in which the fracture relative permeability is used to represent the counterpart at the fracture-matrix interface, is the most common scheme by which to estimate flow mobility for fracture-matrix flow terms. However, such a scheme has a serious flaw, which may lead to unphysical solutions or significant numerical errors. To overcome the limitation of the conventional upstream weighting scheme, this paper presents a physically based modeling approach for estimating physically correct relative permeability in calculating multiphase flow between fractures and the matrix, using continuity of capillary pressure at the fracture-matrix interface. The proposed approach has been implemented into two multiphase reservoir simulators and verified using analytical solutions and laboratory experimental data. The new method is demonstrated to be accurate, numerically efficient, and easy to implement in dual- or multiple-continuum models.
Date: March 16, 2004
Creator: Wu, Y.; Pan, L. & Pruess, K.
Partner: UNT Libraries Government Documents Department

Numerical evaluation of high energy particle effects in magnetohydrodynamics

Description: The interaction of high energy ions with magnetohydrodynamic modes is analyzed. A numerical code is developed which evaluates the contribution of the high energy particles to mode stability using orbit averaging of motion in either analytic or numerically generated equilibria through Hamiltonian guiding center equations. A dispersion relation is then used to evaluate the effect of the particles on the linear mode. Generic behavior of the solutions of the dispersion relation is discussed and dominant contributions of different components of the particle distribution function are identified. Numerical convergence of Monte-Carlo simulations is analyzed. The resulting code ORBIT provides an accurate means of comparing experimental results with the predictions of kinetic magnetohydrodynamics. The method can be extended to include self consistent modification of the particle orbits by the mode, and hence the full nonlinear dynamics of the coupled system.
Date: March 1, 1994
Creator: White, R.B. & Wu, Y.
Partner: UNT Libraries Government Documents Department

Theoretical Studies of Non-Newtonian and Newtonian Fluid Flowthrough Porous Media

Description: A comprehensive theoretical study has been carried out on the flow behavior of both single and multiple phase non-Newtonian fluids in porous media. This work is divided into three parts: (1) development of numerical and analytical solutions; (2) theoretical studies of transient flow of non-Newtonian fluids in porous media; and (3) applications of well test analysis and displacement efficiency evaluation to field problems. A fully implicit, integral finite difference model has been developed for simulation of non-Newtonian and Newtonian fluid flow through porous media. Several commonly-used rheological models of power-law and Bingham plastic non-Newtonian fluids have been incorporated in the simulator. A Buckley-Leverett type analytical solution for one-dimensional, immiscible displacement involving non-Newtonian fluids in porous media has been developed. Based on this solution, a graphic approach for evaluating non-Newtonian displacement efficiency has been developed. The Buckley-Leverett-Welge theory is extended to flow problems with non-Newtonian fluids. An integral method is also presented for the study of transient flow of Bingham fluids in porous media. In addition, two well test analysis methods have been developed for analyzing pressure transient tests of power-law and Bingham fluids, respectively. Applications are included to demonstrate this new technology. The physical mechanisms involved in immiscible displacement with non-Newtonian fluids in porous media have been studied using the Buckley-Leverett type analytical solution. The results show that this kind of displacement is a complicated process and is determined by the rheological properties of the non-Newtonian fluids and the flow conditions, in addition to relative permeability data. In another study, an idealized fracture model has been used to obtain some insights into the flow of a power-law fluid in a double-porosity medium. For flow at a constant rate, non-Newtonian flow behavior in a fractured medium is characterized by two-parallel straight lines on a log-log plot of injection pressure versus time. ...
Date: February 1, 1990
Creator: Wu, Y.S.
Partner: UNT Libraries Government Documents Department

A semi-analytical method for heat sweep calculations in fractured reservoirs

Description: An analytical approximation is developed for purely conductive heat transfer from impermeable blocks of rock to fluids sweeping past the rocks in fractures. The method was incorporated into a multi-phase fluid and heat flow simulator. Comparison with exact analytical solutions and with simulations using a multiple interacting continua approach shows very good accuracy, with no increase in computing time compared to porous medium simulations.
Date: January 1, 1988
Creator: Pruess, K. & Wu, Y.S.
Partner: UNT Libraries Government Documents Department

Self-consistent study of the alpha particle driven TAE mode

Description: The interaction of high energy particles with an Alfven eigenmode is investigated self-consistently by using a realistic kinetic dispersion relation. All important poloidal mode numbers and their radial mode profiles as calculated with the NOVA-K code are included. A Hamiltonian guiding center code is used to simulate the alpha particle motion. The numerical simulations include particle orbit width, nonlinear particle dynamics and the effects of the modes on the particles. Modification of the particle distribution leading to mode saturation is observed. Particle loss is limited to devices in which the alpha particle gyro radius is a significant fraction of the minor radius.
Date: April 1, 1994
Creator: Wu, Y. & White, R. B.
Partner: UNT Libraries Government Documents Department

Preliminary analysis of effects of thermal loading on gas and heat flow within the framework of the LBNL/USGS site-scale model

Description: The US Department of Energy is performing detailed site characterization studies at Yucca Mountain to determine its suitability as a geological repository site for high level nuclear wastes. As part of these research efforts, a three-dimensional, site-scale unsaturated-zone model has been developed at Lawrence Berkeley National Laboratory (LBNL) in collaboration with the US Geological Survey (USGS). The primary objectives of developing the 3-D site-scale model are to predict the ambient hydrogeological conditions and the movement of moisture and gas within the unsaturated zone of the mountain. In addition, the model has the capability of modeling non-isothermal flow and transport phenomena at the mountain. Applications of such a site-scale model should include evaluation of effects of thermal loading on heated gas and heat flow through the mountain for long-term performance assessment of the repository. Emplacement of heat-generating, high-level nuclear wastes at Yucca Mountain would create complex multiphase fluid flow and heat transfer processes. The physical mechanisms include conductive and convective heat transfer, phase change phenomena (vaporization and condensation), flow of liquid and gas phases under variably-saturated condition, diffusion and dispersion of vapor and gas, vapor sorption, and vapor-pressure lowering effects. The heterogeneity of complicated geological setting at Yucca Mountain, such as alternating, layers of porous-fractured rocks, will significantly affect the processes of fluid and heat flow.
Date: December 1, 1995
Creator: Wu, Y.S.; Chen, G. & Bodvarsson, G.
Partner: UNT Libraries Government Documents Department

A model of shape memory materials with hierarchical twinning: Statics and dynamics

Description: We consider a model of shape memory material in which hierarchical twinning near the habit plane (austenite-martensite interface) is a new and crucial ingredient. The model includes (1) a triple-well potential ({phi} model) in local shear strain, (2) strain gradient terms up to second order in strain and fourth order in gradient, and (3) all symmetry allowed compositional fluctuation induced strain gradient terms. The last term favors hierarchy which enables communication between macroscopic (cm) and microscopic ({Angstrom}) regions essential for shape memory. Hierarchy also stabilizes between formation (critical pattern of twins). External stress or pressure (pattern) modulates the spacing of domain walls. Therefore the ``pattern`` is encoded in the modulated hierarchical variation of the depth and width of the twins. This hierarchy of length scales provides a hierarchy of time scales and thus the possibility of non-exponential decay. The four processes of the complete shape memory cycle -- write, record, erase and recall -- are explained within this model. Preliminary results based on 2D Langevin dynamics are shown for tweed and hierarchy formation.
Date: July 1, 1995
Creator: Saxena, A.; Bishop, A.R.; Shenoy, S.R.; Wu, Y. & Lookman, T.
Partner: UNT Libraries Government Documents Department

CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS

Description: This work presents modeling studies investigating the effects of capillary barriers on fluid-flow and tracer-transport processes in the unsaturated zone of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. These studies are designed to identify factors controlling the formation of capillary barriers and to estimate their effects on the extent of possible large-scale lateral flow in unsaturated fracture rocks. The modeling approach is based on a continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. Flow processes in fractured porous rock are described using a dual-continuum concept. In addition, approximate analytical solutions are developed and used for assessing capillary-barrier effects in fractured rocks. This study indicates that under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary-barrier effects exist for significantly diverting moisture flow.
Date: October 1, 2000
Creator: Wu, Y.S.; Zhang, W.; Pan, L.; Hinds, J. & Bodvarsson, G.
Partner: UNT Libraries Government Documents Department

Sensitivity and uncertainty analyses applied to one-dimensional radionuclide transport in a layered fractured rock: MULTFRAC --Analytic solutions and local sensitivities; Phase 2, Iterative performance assessment: Volume 1

Description: Exact analytical solutions based on the Laplace transforms are derived for describing the one-dimensional space-time-dependent, advective transport of a decaying species in a layered, saturated rock system intersected by a planar fracture of varying aperture. These solutions, which account for advection in fracture, molecular diffusion into the rock matrix, adsorption in both fracture and matrix, and radioactive decay, predict the concentrations in both fracture and rock matrix and the cumulative mass in the fracture. The solute migration domain in both fracture and rock is assumed to be semi-infinite with non-zero initial conditions. The concentration of each nuclide at the source is allowed to decay either continuously or according to some periodical fluctuations where both are subjected to either a step or band release mode. Two numerical examples related to the transport of Np-237 and Cm-245 in a five-layered system of fractured rock were used to verify these solutions with several well established evaluation methods of Laplace inversion integrals in the real and complex domain. In addition, with respect to the model parameters, a comparison of the analytically derived local sensitivities for the concentration and cumulative mass of Np-237 in the fracture with the ones obtained through a finite-difference method of approximation is also reported.
Date: December 1, 1992
Creator: Gureghian, A. B.; Wu, Y. T.; Sagar, B. & Codell, R. A.
Partner: UNT Libraries Government Documents Department

Specific heat of the high-T/sub c/ superconductor (Bi/sub 1. 66/Pb/sub 0. 34/)Ca/sub 2/Sr/sub 2/Cu/sub 3/O/sub 10/

Description: The specific heat (C) was measured for H = 0 and 7T in the ranges 0.4 to 20K and 65 to 125K. The coefficient of the low-temperature linear term in C was 0 /plus minus/ 0.5 mJ/K/sup 2//center dot/mole. On initial cooling, an anomaly in C was observed at T/sub c/, but there were dramatic temperature hysteresis effects. 5 refs., 4 figs.
Date: June 1, 1989
Creator: Fisher, R.A.; Kim, S.; Wu, Y.; Phillips, N.E.; Ledbetter, H.M. & Togano, K.
Partner: UNT Libraries Government Documents Department

An x-ray microprobe using focussing optics with a synchrotron radiation source

Description: An x-ray microprobe can be used to produce maps of the concentration of elements in a sample. Synchrotron radiation provides x-ray beams with enough intensity and collimation to make possible elemental images with femtogram sensitivity. The use of focussing x-ray mirrors made from synthetic multilayers with a synchrotron x-ray beam allows beam spot sizes of less than 10 /mu/m /times/ 10 /mu/m to be produced. Since minimal sample preparation is required and a vacuum environment is not necessary, there will be a wide variety of applications for such microprobes. 8 refs., 6 figs.
Date: January 1, 1989
Creator: Thompson, A.C.; Underwood, J.H.; Wu, Y. & Giauque, R.D.
Partner: UNT Libraries Government Documents Department

Validation and testing of the VAM2D computer code

Description: This document describes two modeling studies conducted by HydroGeoLogic, Inc. for the US NRC under contract no. NRC-04089-090, entitled, Validation and Testing of the VAM2D Computer Code.'' VAM2D is a two-dimensional, variably saturated flow and transport code, with applications for performance assessment of nuclear waste disposal. The computer code itself is documented in a separate NUREG document (NUREG/CR-5352, 1989). The studies presented in this report involve application of the VAM2D code to two diverse subsurface modeling problems. The first one involves modeling of infiltration and redistribution of water and solutes in an initially dry, heterogeneous field soil. This application involves detailed modeling over a relatively short, 9-month time period. The second problem pertains to the application of VAM2D to the modeling of a waste disposal facility in a fractured clay, over much larger space and time scales and with particular emphasis on the applicability and reliability of using equivalent porous medium approach for simulating flow and transport in fractured geologic media. Reflecting the separate and distinct nature of the two problems studied, this report is organized in two separate parts. 61 refs., 31 figs., 9 tabs.
Date: October 1, 1991
Creator: Kool, J. B. & Wu, Y. S.
Partner: UNT Libraries Government Documents Department

Ground-water flow and transport modeling of the NRC-licensed waste disposal facility, West Valley, New York

Description: This report describes a simulation study of groundwater flow and radionuclide transport from disposal at the NRC licensed waste disposal facility in West Valley, New York. A transient, precipitation driven, flow model of the near-surface fractured till layer and underlying unweathered till was developed and calibrated against observed inflow data into a recently constructed interceptor trench for the period March--May 1990. The results suggest that lateral flow through the upper, fractured till layer may be more significant than indicated by previous, steady state flow modeling studies. A conclusive assessment of the actual magnitude of lateral flow through the fractured till could however not be made. A primary factor contributing to this uncertainty is the unknown contribution of vertical infiltration through the interceptor trench cap to the total trench inflow. The second part of the investigation involved simulation of the migration of Sr-90, Cs-137 and Pu-239 from the one of the fuel hull disposal pits. A first-order radionuclide leach rate with rate coefficient of 10{sup {minus}6}/day was assumed to describe radionuclide release into the disposal pit. The simulations indicated that for wastes buried below the fractured till zone, no significant migration would occur. However, under the assumed conditions, significant lateral migration could occur for radionuclides present in the upper, fractured till zone. 23 refs., 68 figs., 12 tabs.
Date: October 1, 1991
Creator: Kool, J. B. & Wu, Y. S.
Partner: UNT Libraries Government Documents Department

Fusion-Fission Research Facility (FFRF) as a Practical Step Toward Hybrids

Description: The project of ASIPP (with PPPL participation), called FFRF, (R/a=4/1 m/m, Ipl=5 MA, Btor=4-6 T, PDT=50-100 MW, Pfission=80-4000 MW, 1 m thick blanket) is outlined. FFRF stands for the Fusion-Fission Research Facility with a unique fusion mission and a pioneering mission of merging fusion and fission for accumulation of design, experimental, and operational data for future hybrid applications. The design of FFRF will use as much as possible the EAST and ITER design experience. On the other hand, FFRF strongly relies on new, Lithium Wall Fusion plasma regimes, the development of which has already started in the US and China.
Date: November 18, 2010
Creator: Zakharov, L.; Li, J. & Wu, Y.
Partner: UNT Libraries Government Documents Department

Observations And Measurements of Anomalous Hollow Electron Beams in a Storage Ring

Description: Anomalous hollow electron beams have been recently observed in the Duke storage ring. With a single bunch beam in a lattice with a negative chromaticity, a hollow beam can be created. This beam consists of a solid core beam inside and a large ring beam outside. In this paper, we report the measurements of the hollow beam phenomenon, including its distinct image pattern and spectrum signature, and its evolution with time. By capturing the post-instability bursting beam, the hollow beam is a unique model system for studying transverse instabilities, in particular, the interplay of the wakefield and lattice nonlinearity. The hollow beam can also be used as a tool to study linear and nonlinear particle dynamics in the storage ring.
Date: February 6, 2006
Creator: Wu, Y.K.; Li, J.; U., /Duke; Wu, J. & /SLAC
Partner: UNT Libraries Government Documents Department

Development and applications of GREET 2.7 -- The Transportation Vehicle-CycleModel.

Description: Argonne National Laboratory has developed a vehicle-cycle module for the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model. The fuel-cycle GREET model has been cited extensively and contains data on fuel cycles and vehicle operations. The vehicle-cycle model evaluates the energy and emission effects associated with vehicle material recovery and production, vehicle component fabrication, vehicle assembly, and vehicle disposal/recycling. With the addition of the vehicle-cycle module, the GREET model now provides a comprehensive, lifecycle-based approach to compare the energy use and emissions of conventional and advanced vehicle technologies (e.g., hybrid electric vehicles and fuel cell vehicles). This report details the development and application of the GREET 2.7 model. The current model includes six vehicles--a conventional material and a lightweight material version of a mid-size passenger car with the following powertrain systems: internal combustion engine, internal combustion engine with hybrid configuration, and fuel cell with hybrid configuration. The model calculates the energy use and emissions that are required for vehicle component production; battery production; fluid production and use; and vehicle assembly, disposal, and recycling. This report also presents vehicle-cycle modeling results. In order to put these results in a broad perspective, the fuel-cycle model (GREET 1.7) was used in conjunction with the vehicle-cycle model (GREET 2.7) to estimate total energy-cycle results.
Date: December 20, 2006
Creator: Burnham, A.; Wang, M. Q. & Wu, Y.
Partner: UNT Libraries Government Documents Department

MODELING COUPLED PROCESSES OF MULTIPHASE FLOW AND HEAT TRANSFER IN UNSATURATED FRACTURED ROCK

Description: A mountain-scale, thermal-hydrologic (TH) numerical model is developed for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository at Yucca Mountain, Nevada, USA. The TH model, consisting of three-dimensional (3-D) representations of the unsaturated zone, is based on the current repository design, drift layout, and thermal loading scenario under estimated current and future climate conditions. More specifically, the TH model implements the current geological framework and hydrogeological conceptual models, and incorporates the most updated, best-estimated input parameters. This mountain-scale TH model simulates the coupled TH processes related to mountain-scale multiphase fluid flow, and evaluates the impact of radioactive waste heat on the hydrogeological system, including thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. For a better description of the ambient geothermal condition of the unsaturated zone system, the TH model is first calibrated against measured borehole temperature data. The ambient temperature calibration provides the necessary surface and water table boundary as well as initial conditions. Then, the TH model is used to obtain scientific understanding of TH processes in the Yucca Mountain unsaturated zone under the designed schedule of repository thermal load.
Date: February 28, 2006
Creator: Wu, Y.; Mukhopadhyay, S.; Zhang, K. & Bodvarsson, G.S.
Partner: UNT Libraries Government Documents Department

Analyzing Unsatirated Flow Patterns in Fractured Rock Using an Integrated Modeling Approach

Description: Characterizing percolation patterns in unsaturated fractured rock has posed a greater challenge to modeling investigations than comparable saturated zone studies, because of the heterogeneous nature of unsaturated media and the great number of variables impacting unsaturated flow. This paper presents an integrated modeling methodology for quantitatively characterizing percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The modeling approach integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model for modeling analyses. It takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. Modeling results are examined against different types of field-measured data and then used to evaluate different hydrogeological conceptualizations and their results of flow patterns in the unsaturated zone. In particular, this model provides a much clearer understanding of percolation patterns and flow behavior through the unsaturated zone, both crucial issues in assessing repository performance. The integrated approach for quantifying Yucca Mountain's flow system is demonstrated to provide a practical modeling tool for characterizing flow and transport processes in complex subsurface systems.
Date: August 3, 2006
Creator: Wu, Y.S.; Lu, G.; Zhang, K.; Pan, L. & Bodvarsson, G.S.
Partner: UNT Libraries Government Documents Department