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Critical Function Models for Operation of the International Space Station

Description: Long duration and exploration class space missions will place new requirements on human performance when compared to current space shuttle missions. Specifically, assembly and operation of the International Space Station (ISS) will place significant new demands on the crew. For example, maintenance of systems that provide habitability will become an ongoing activity for the international flight crews. Tasks for maintaining space station habitability will need to be integrated with tasks associated with scientific research. In addition, tasks and resources will need to be prioritized and allocated dynamically in response to changing operational conditions and unplanned system breakdowns. This paper describes an ongoing program to develop a habitability index (HI) for space operations based on the critical function approach. This pilot project focuses on adaptation of the critical function approach to develop a habitability index specifically tailored for space operations. Further work will then be needed to expand and validate the habitability index for application in the ISS operational environment.
Date: November 1, 2000
Creator: Nelson, William Roy & Bagian, T. M.
Partner: UNT Libraries Government Documents Department

Tank waste remediation system simulation analysis retrieval model

Description: The goal of simulation was to test tll(., consequences of assumptions. For the TWRS SIMAN Retrieval Model, l@lie specific assumptions are primarily defined with respect to waste processing arid transfer timing. The model tracks 73 chem1913ical constituents from underground waste tanks to glass; yet, the detailed (@hemistrv and complete set of unit operations of the TWRS process flow sheet are represented only at the level necessary to define the waste processing and transfer logic and to estimate the feed composition for the treatment facilities. Tlierefor(,, the model should net be regarded as a substitute for the TWRS process flow sheet. Pra(!ticallv the model functions as a dyrt(imic extension of the flow sheet model. I I The following sections present the description, assunipt@ions, architecture, arid evalua- tion of the TWRS SIMAN Retrieval Model. Section 2 describes the model in terms of an overview of the processes represented. Section 3 presents the assumptions for the simulation model. Specific assumptions 9.tt(l parameter values used in the model are provided for waste retrieval, pretreatment, low-level waste (LLNN7) immobilization, and high-level waste (HLW) immobilization functions. Section 4 describes the model in terms of its functional architec- rare to d(@fine a basis for a systematic evaluation of the model. Finally, Section 5 documents an independent test and evaluation of the niodel`s performance (i.e., the verification and validation). Additionally, Appendix A gives a complete listing of the tank inventory used. Appendix B documents the verification and validation plan that was used for the (Section 5) evaluation work. A description and listing of all the model variables is given in Appendix C along with a complete source listing.
Date: September 30, 1996
Creator: Fordham, R. A.
Partner: UNT Libraries Government Documents Department

Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil

Description: A NACA 4415 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from {minus}10{degree} to +40{degree} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, these were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Steady state results of the NACA 4415 testing at Reynolds number of 1.25 million showed a baseline maximum lift coefficient of 1.30 at 12.3{degree} angle of attack. The application of LEGR reduced the maximum lift coefficient by 20% and increased the 0.0090 minimum drag coefficient value by 62%. The zero lift pitching moment of {minus}0.0967 showed a 13% reduction in magnitude to {minus}0.0842 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {+-}5.5{degree} and {+-}10{degree}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude, and both unsteady maximum lift coefficients were greater than the steady state values. Stall is delayed on the airfoil while the angle of attack is increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack. In addition, with LEGR, the hysteresis behavior persisted into lower angles of attack than for the clean case.
Date: July 1, 1996
Creator: Hoffmann, M.J.; Reuss Ramsay, R. & Gregorek, G.M.
Partner: UNT Libraries Government Documents Department

A study of pitch oscillation and roughness on airfoils used for horizontal axis wind turbines

Description: Under subcontract XF-1-11009-3 the Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) with the National Renewable Energy Laboratory (NREL) developed an extensive database of empirical aerodynamic data. These data will assist in the development of analytical models and in the design of new airfoils for wind turbines. To accomplish the main objective, airfoil models were designed, built and wind tunnel tested with and without model leading edge grit roughness (LEGR). LEGR simulates surface irregularities due to the accumulation of insect debris, ice, and/or the aging process. This report is a summary of project project activity for Phase III, which encompasses the time period from September 17, 1 993 to September 6, 1 994.
Date: December 1, 1995
Creator: Gregorek, G.M.; Hoffmann, M.J.; Ramsay, R.R. & Janiszewska, J.M.
Partner: UNT Libraries Government Documents Department

Development of the 3rd Generation ECR ion source

Description: The LBNL 3rd Generation ECR ion source has progressed from a concept to the fabrication of a full scale prototype superconducting magnet structure. This new ECR ion source will combine the recent ECR ion source techniques that significantly enhance the production of high charge state ions. The design includes a plasma chamber made from aluminum to provide additional cold electrons, three separate microwave feeds to allow multiple-frequency plasma heating (at 10, 14 and 18 GHz or at 6, 10 and 14 GHz) and very high magnetic mirror fields. The design calls for mirror fields of 4 T at injection and 3 T at extraction and for a radial field strength at the wall of 2.4 T. The prototype superconducting magnet structure which consists of three solenoid coils and six race track coils with iron poles forming the sextupole has been tested in a vertical dewar. After training, the sextupole magnet reached 105% of its design current with the solenoids off. With the solenoids operating at approximately 70% of their full design field, the sextuple coils operated at 95% of the design value which corresponds to a sextupole field strength at the plasma wall of more than 2.1 T.
Date: September 1, 1997
Creator: Lyneis, C.M.; Xie, Z.Q. & Taylor, C.E.
Partner: UNT Libraries Government Documents Department

Inductrack demonstration model

Description: A small-scale model track of a new type of magnetic levitation system (dubbed the ``Inductrack`` system), and a passively magnetically levitated cart, has been designed, constructed and operated. The track consists of a close-packed array of rectangular levitation coils, 15 centimeters in width transversely and 20 meters in length. The array of coils is inductively loaded above and below its lower horizontal section with ferrite tiles. Paralleling the levitation coils on each side are aluminum-channel rails on which ride auxiliary wheels attached to the cart. The cart has, on its lower surface and on its sides, fore and aft, special arrays (``Halbach arrays``) of permanent magnet bars that produce a strong periodic magnetic field below the cart. This magnetic field, when the cart is in motion, induces repelling currents in the Inductrack coils, levitating it and centering it transversely. When mechanically launched (with a pulley- and-weight system) at speeds substantially above a ``transition speed`` of about 2 meters per second, the cart levitated and flew stably down the track, settling to rest on its wheels near the end of the track. In the last phase of the program an electromagnetic launching section consisting of another array of coils, connected to pulse-driver circuits, was added at the beginning of the track. Aided by an initial launch (from stretched ``bungee`` cords), this electromagnetic launching system was operated successfully, resulting again in levitation and subsequent stable flight of the cart.
Date: February 3, 1998
Creator: Post, R.F.
Partner: UNT Libraries Government Documents Department

Environmental compliance Modeling at Lawrence Livermore National Laboratory

Description: This paper presents a post-rehabilitation monitoring and modeling study of the sanitary sewer system at Lawrence Livermore National Laboratory (LLNL). The study evaluated effectiveness of sewer system rehabilitation efforts and defined benchmarks for environmental success. A PCSWMM model for the sanitary sewer system was developed and applied to demonstrate the success of a $5 million rehabilitation effort. It determined that rainfall-dependent inflow and infiltration (RDI&I) had been reduced by 88%, and that system upgrades adequately manage predicted peak flows. An ongoing modeling and analysis program currently assists management in evaluating the system`s needs for continuing maintenance and further upgrades. This paper also summarizes a 1989 study that evaluated data collected from December 1, 1988, to January 6, 1989, to determine the adequacy of the LLNL sewer system to accommodate present and future peak flows, and the Sanitary Sewer Rehabilitation (SSR) project, which took place from 1991 through 1995.
Date: February 1, 1998
Creator: Brandstetter, E.R., LLNL
Partner: UNT Libraries Government Documents Department

Design and operations of Hall thruster with segmented electrodes

Description: Principles of the Hall thruster with segmented electrodes are explored. A suitable vacuum facility was put into service. For purposes of comparison between segmented and conventional thruster approaches, a modular laboratory prototype thruster was designed and built. Under conventional operation, the thruster achieves state-of-the-art efficiencies (56% at 300 V and 890 W). Very preliminary results under operation with segmented electrodes are also described.
Date: December 10, 1999
Creator: Fisch, N.J.; Raitses, Y.; Dorf, L.A. & Litvak, A.A.
Partner: UNT Libraries Government Documents Department

Four great challenges confronting our understanding and modeling of sliding friction

Description: This paper addresses four challenges whose solutions may together enable significant progress in the predication and control of friction for energy conservation. Posed as questions these are: (1) how can materials with greatly different properties and compositions produce similar kinetic friction coefficients when tested under comparable conditions; (2) how is it possible that the kinetic friction coefficient for the same materials pair can differ greatly when it is slid in different tribosystems; (3) how can frictional phenomena at different size scales be reconciled; and (4) how can the effects of the machine, the materials (including lubricants) and the environment be successfully incorporated into quantitative and predictive friction models? Examples related to these four challenges are provided, as are possible approaches for attacking them in future research efforts.
Date: August 1, 1997
Creator: Blau, P.J.
Partner: UNT Libraries Government Documents Department

Effects of grit roughness and pitch oscillations on the S815 airfoil

Description: Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are cause by the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S815 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 x 5 subsonic wind tunnel (3 x 5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions were 0.75, 1, 1.25, and 1.4 million, while the angle of attack ranged from {minus}20{degree} to +40{degree}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {+-}5.5{degree} and {+-}10{degree}, at mean angles of attack of 8{degree}, 14{degree}, and 20{degree}. For purposes herein, any reference to unsteady conditions means that the model was in pitch oscillation about the quarter chord.
Date: July 1, 1996
Creator: Reuss Ramsay, R.; Hoffman, M.J. & Gregorek, G.M.
Partner: UNT Libraries Government Documents Department

Critique of ``Expected Value`` models

Description: There are a number of models in the defense community which use a methodology referred to as ``Expected Value`` to perform sequential calculations of unit attritions or expenditures. The methodology applied to two-sided, dependent, sequential events can result in an incorrect model. An example of such an incorrect model is offered to show that these models may yield results which deviate significantly from a stochastic or Markov process approach. The example was derived from an informal discussion at the Center for Naval Analyses.
Date: June 1, 1996
Creator: May, W.L.
Partner: UNT Libraries Government Documents Department

Development of nuclear analysis capabilities for DOE waste management activities. 1998 annual progress report

Description: 'The objective of this project is to develop and demonstrate prototypic analysis capabilities that can be used by the nuclear safety analysis practitioners to: (1) demonstrate a more thorough understanding of the underlying physics phenomena that can lead to improved reliability and defensibility of safety evaluations; and (2) optimize operations related to the handling, storage, transportation, and disposal of fissile material and DOE spent fuel. To address these problems, the project will investigate the implementation of sensitivity and uncertainty methods within existing Monte Carlo codes used for criticality safety analyses, as well as within a new deterministic code that allows specification of arbitrary grids to accurately model the geometry details required in a criticality safety analysis. This capability can facilitate improved estimations of the required subcritical margin and potentially enable the use of a broader range of experiments in the validation process. The new arbitrary-grid radiation transport code will also enable detailed geometric modeling valuable for improved accuracy in application to a myriad of other problems related to waste characterization. Application to these problems will also be explored. This report summarizes the progress achieved after only seven months of work on a three-year project.'
Date: June 1, 1998
Creator: Parks, C.V.; DeHart, M.D.; Broadhead, B.L. & Hopper, C.M.
Partner: UNT Libraries Government Documents Department

A Study of the Effect of Mobility Ratios on Pattern Displacement Behavior and Steamlines to Infer Permeability Media, SUPRI TR-115

Description: Pattern geometry plays a major role in determining oil recovery during secondary and enhanced oil recovery operations. Although simulation is an important tool for design and evaluation, the first step often involves rough calculations based upon areal sweep efficiencies of displacements in homogeneous, two-dimensional, scaled, physical models. These results are available as a function of the displacement pattern and the mobility ratio, M. The mobility ratio is simply the mobility of the displacing phase over that of the displaced, or resident, phase. Because it is possible to compute sweep efficiency analytically when the displacing and displaced phase have the same mobility, scaled physical model results have been verified for unit mobility ratios.
Date: August 9, 1999
Creator: Brigham, William E.; Kovscek, Anthony R. & Wang, Yuandong
Partner: UNT Libraries Government Documents Department

Methods for Geometric Modeling of Electronic Inspection Data

Description: The Oak Ridge Y-12 plant has implemented a methodology for characterizing parts and assemblies based on their as-measured condition. Complete solid models of each part in an assembly are created to represent these measurements. The models produced can be analyzed for mass properties, relative shape variations, interference checking, and optimal mating between components. This report describes the methodology used to take a relatively sparse set of measured inspection points and generate a representative fully analytical solid model.
Date: June 28, 1999
Creator: Taylor, J.R.
Partner: UNT Libraries Government Documents Department

A framework for constructing adaptive and reconfigurable systems

Description: This paper presents a software approach to augmenting existing real-time systems with self-adaptation capabilities. In this approach, based on the control loop paradigm commonly used in industrial control, self-adaptation is decomposed into observing system events, inferring necessary changes based on a system's functional model, and activating appropriate adaptation procedures. The solution adopts an architectural decomposition that emphasizes independence and separation of concerns. It encapsulates observation, modeling and correction into separate modules to allow for easier customization of the adaptive behavior and flexibility in selecting implementation technologies.
Date: May 1, 2007
Creator: Poirot, Pierre-Etienne; Nogiec, Jerzy & Ren, Shangping
Partner: UNT Libraries Government Documents Department

Whole-arm obstacle avoidance system conceptual design

Description: Whole-arm obstacle avoidance is needed for a variety of robotic applications in the Environmental Restoration and Waste Management (ER&WM) Program. Typical industrial applications of robotics involve well-defined workspaces, allowing a predetermined knowledge of collision-free paths for manipulator motion. In the unstructured or poorly defined hazardous environments of the ER&WM Program, the potential for significant problems resulting from collisions between manipulators and the environment in which they are utilized is great. The conceptual design for a sensing system that will provide protection against such collisions is described herein. The whole-arm obstacle avoidance system consists of a set of sensor ``bracelets,`` which cover the surface area of the manipulator links to the maximum extent practical, and a host processor. The host processor accepts commands from the robot control system, controls the operation of the sensors, manipulates data received from the bracelets, and makes the data available to the manipulator control system. The bracelets consist of a subset of the sensors, associated sensor interface electronics, and a bracelet interface. Redundant communications links between the host processor and the bracelets are provided, allowing single-point failure protection. The system allows reporting of 8-bit data from up to 1000 sensors at a minimum of 50 Hz. While the initial prototype implementation of the system utilizes capacitance proximity sensor, the system concept allows multiple types of sensors. These sensors are uniquely addressable, allowing remote calibration, thresholding at the bracelet, and correlation of a sensor measurement with the associated sensor and its location on the manipulator. Variable resolution allows high-speed, single-bit sensing as well as lower-speed higher-resolution sensing, which is necessary for sensor calibration and potentially useful in control.
Date: April 1, 1993
Creator: Wintenberg, A. L.; Butler, P. L.; Babcock, S. M.; Ericson, M. N. & Britton, C. L. Jr.
Partner: UNT Libraries Government Documents Department

Real-Time Risk and Fault Management in the Mission Evaluation Room of the International Space Station

Description: Effective anomaly resolution in the Mission Evaluation Room (MER) of the International Space Station (ISS) requires consideration of risk in the process of identifying faults and developing corrective actions. Risk models such as fault trees from the ISS Probablistic Risk Assessment (PRA) can be used to support anomaly resolution, but the functionality required goes significantly beyond what the PRA could provide. Methods and tools are needed that can systematically guide the identification of root causes for on-orbit anomalies, and to develop effective corrective actions that address the event and its consequences without undue risk to the crew or the mission. In addition, an overall information management framework is needed so that risk can be systematically incorporated in the process, and effectively communicated across all the disciplines and levels of management within the space station program. The commercial nuclear power industry developed such a decision making framework, known as the critical safety function approach, to guide emergency response following the accident at Three Mile Island in 1979. This report identifies new methods, tools, and decision processes that can be used to enhance anomaly resolution in the ISS Mission Evaluation Room. Current anomaly resolution processes were reviewed to identify requirements for effective real-time risk and fault management. Experience gained in other domains, especially the commercial nuclear power industry, was reviewed to identify applicable methods and tools. Recommendations were developed for next-generation tools to support MER anomaly resolution, and a plan for implementing the recommendations was formulated. The foundation of the proposed toolset will be a "Mission Success Framework" designed to integrate and guide the anomaly resolution process, and to facilitate consistent communication across disciplines while focusing on the overriding importance of mission success.
Date: May 1, 2003
Creator: Nelson, William R. & Novack, Steven D.
Partner: UNT Libraries Government Documents Department

Status of engineering development of CCDTL for accelerator production of tritium

Description: The Coupled-Cavity Drift Tube Linac (CCDTL) is a relatively new RF accelerator structure which plays a major role in the APT Low-Energy Linac (LEL) design. Engineering development is pushing ahead on several fronts, including thermal management, fabrication procedures, cavity and coupling slot tuning, high-power prototype fabrication and testing, supports and alignment, vacuum, and provisions for beam diagnostics. Fabrication of the CCDTL Low-Beta Hot Model is nearly complete, and high-power RF tests will commence soon. In 1999, the authors will begin the fabrication of 11 meters of CCDTL to be added to the Low-Energy Demonstration Accelerator. In 2001, it will take the 100 mA beam from 6.7 MeV to 10.05 MeV, producing the world`s most powerful proton beam. The authors are also starting the design of a CCDTL 96 MeV Hot Model to demonstrate cooling of an intermediate-Beta version of the structure. The 14cm-long, 9cm diameter drift tube has roughly 5kW dissipated on it. This all leads to the final mechanical design of the 113m long CCDTL for the APT plant linac.
Date: December 31, 1998
Creator: Wood, R.L.; Billen, J.H.; Hunter, W.T.; Leslie, P.O.; Roybal, R.J. & Sigler, F.E.
Partner: UNT Libraries Government Documents Department

Shake table testing of structural clay tile infilled frames

Description: Two steel frames with structural clay tile infills were tested under simulated seismic loads in both the out-of-plane and in-plane direction. Out-of-plane testing showed that infill panels separate from their bounding frame, and respond at their own natural frequency during a seismic excitation. Due to arching, the panels remain stable. In-plane seismic testing showed similar behavior patterns to previous static testing. The natural frequency was adequately predicted using a piecewise linear equivalent strut analytical method. The structure was then subjected to over one thousand cycles of loading using a sine sweep before failure.
Date: March 8, 1996
Creator: Bennett, R.M.; Fowler, J.J. & Flanagan, R.D.
Partner: UNT Libraries Government Documents Department

White paper on the proposed design, development, and implementation of a monitored retrievable storage module and the siting criteria for spent nuclear fuel

Description: Congress enacted the Nuclear Waste Policy (NWP) Act in 1982 as comprehensive legislation for the DOE to locate, build, and operate repositories to permanently dispose of spent nuclear fuel and other high-level wastes. In 1987, Congress amended the NWP Act and authorized the DOE to site, construct, and operate one Monitored Retrievable Storage (MRS) facility. The MRS facility was planned as a means to enhance the flexibility and reliability of the overall waste management system. This white paper presents a broad prospectus of the scientific and regulatory capabilities at Los Alamos National Laboratory and outlines the methodology to design and implement an MRS test module. This proposed module will incorporate the flexibility to store all types of spent nuclear fuel above or below ground level and will be fully monitored for the residence time of the spent fuel in the MRS module. The purpose of this test module is to define the parameters necessary to build a simple and economical MRS system. Demonstration of the proposed MRS test module will be important because it will form the basis for an integrated MRS site model.
Date: January 1996
Creator: Villarreal, B. & Knobeloch, D.
Partner: UNT Libraries Government Documents Department

Small Inertial Fusion Energy (IFE) demonstration reactors

Description: ICF target design studies done for the Nova Upgrade have identified conditions under which the target ignition ``cliff`` is shifted to much lower drive energy albeit with the penalty that the gain achieved at a given energy is also smaller. These targets would repeatedly produce the output and spectra of a higher gain targets at low yield. They should, thus, allow building much smaller R&D reactors with full thermonuclear effects. Demonstration reactor at the 1 to 100 MW{sub e} level appear to be feasible with driver energies of 0.5 to 2.0 MJ per pulse. These smaller, less expensive test and demonstration facilities should result in lower IFE development cost. If the U.S. government builds a driver and target factory, it is also conceivable that commercial organizations could build their own scaled concepts of IFE reactors using the beams and targets supplied by the government`s facilities.
Date: October 3, 1991
Creator: Hogan, W.J.
Partner: UNT Libraries Government Documents Department

Laser Spray Fabrication for Net-Shape Rapid Product Realization LDRD

Description: The primary purpose of this LDRD project was to characterize the laser deposition process and determine the feasibility of fabricating complex near-net shapes directly from a CAD solid model. Process characterization provided direction in developing a system to fabricate complex shapes directly from a CAD solid model. Our goal for this LDRD was to develop a system that is robust and provides a significant advancement to existing technologies (e.g., polymeric-based rapid prototyping, laser welding). Development of the process will allow design engineers to produce functional models of their designs directly from CAD files. The turnaround time for complex geometrical shaped parts will be hours instead of days and days instead of months. With reduced turnaround time, more time can be spent on the product-design phase to ensure that the best component design is achieved. Maturation of this technology will revolutionize the way the world produces structural components.
Date: April 1, 1999
Creator: Atwood, C.L.; Ensz, M.T.; Greene, D.L.; Griffith, M.L.; Harwell, L.D.; Jeantette, F.P. et al.
Partner: UNT Libraries Government Documents Department

Waste inventory and preliminary source term model for the Greater Confinement Disposal site at the Nevada Test Site

Description: Currently, there are several Greater Confinement Disposal (GCD) boreholes at the Radioactive Waste Management Site (RWMS) for the Nevada Test Site. These are intermediate-depth boreholes used for the disposal of special case wastes, that is, radioactive waste within the Department of Energy complex that do not meet the criteria established for disposal of high-level waste, transuranic waste, or low-level waste. A performance assessment is needed to evaluate the safety of the GCD site, and to examine the feasibility of the GCD disposal concept as a disposal solution for special case wastes in general. This report documents the effort in defining all the waste inventory presently disposed of at the GCD site, and the inventory and release model to be used in a performance assessment for compliance with the Environmental Protection Agency`s 40 CFR 191.
Date: December 1991
Creator: Chu, M. S. Y. & Bernard, E. A.
Partner: UNT Libraries Government Documents Department