Some observations concerning alpha instabilities and driven tokamak reactors (open access)

Some observations concerning alpha instabilities and driven tokamak reactors

While much research is needed to assess the reality and consequences of alpha-induced instabilities, crude transport estimates for the TAE mode indicate that as little as 10 percent of the alpha energy would be deposited in steady-state. Even so, CIT and the ITER technology phase would meet their minimal goals of Q = 5 if only the alphas themselves are ejected and not the fuel itself. Higher gain up to Q {approximately} 20 may be possible in driven reactors of a different design, depending on the effects of aspect ratio and other geometric features on confinement. Very high gain still requires alpha testing. 5 refs.
Date: July 16, 1990
Creator: Fowler, T.K. (California Univ., Berkeley, CA (USA))
Object Type: Report
System: The UNT Digital Library
Hydrogen from renewable resources research (open access)

Hydrogen from renewable resources research

In 1986 the Hawaii Natural Energy Institute (HNEI) and the Florida Solar Energy Center (FSEC) were contracted by the Solar Energy Research Institute (SERI) to conduct an assessment of hydrogen production technologies and economic feasibilities of the production and use of hydrogen from renewable resources. In the 1989/90 period all monies were directed toward research and development with an emphasis on integration of tasks, focusing on two important issues, production and storage. The current year's efforts consisted of four tasks, one task containing three subtasks: Hydrogen Production by Gasification of Glucose and Wet Biomass in Supercritical Water; Photoelectrochemical Production of Hydrogen; Photoemission and Photoluminescence Studies of Catalyzed Photoelectrode Surfaces for Hydrogen Production; Solar Energy Chemical Conversion by Means of Photoelectrochemical (PEC) Methods Using Coated Silicon Electrodes; Assessment of Impedance Spectroscopy Methods for Evaluation of Semiconductor-Electrolyte Interfaces; Solar Energy Conversion with Cyanobacteria; Nonclassical Polyhydride Metal Complexes as Hydrogen Storage Materials. 61 refs., 22 figs., 11 tabs.
Date: July 1, 1990
Creator: Takahashi, P.K. & McKinley, K.R.
Object Type: Report
System: The UNT Digital Library
Supersymmetry breaking from superstrings and the gauge hierarchy (open access)

Supersymmetry breaking from superstrings and the gauge hierarchy

The gauge hierarchy problem is reviewed and a class of effective field theories obtained from superstrings is described. These are characterized by a classical symmetry, related to the space-time duality of string theory, that is responsible for the suppression of observable supersymmetry breaking effects. At the quantum level, the symmetry is broken by anomalies that provide the seed of observable supersymmetry breaking, and an acceptably large gauge hierarchy may be generated. 39 refs.
Date: July 11, 1990
Creator: Gaillard, M.K. (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library
Impulse gage development for the 100-200 ktap range (open access)

Impulse gage development for the 100-200 ktap range

Special effects underground test (UGT) material response and source diagnostics data require impulse gages that can be used in the 50--150 ktap range and have equilibrated from electrical and mechanical noise sources within 0.001 s. Such gages were designed, analyzed, and tested under this program. One- and two-dimensional stress propagation calculations were performed and predictions were developed for deformation of the gage specimen cup. These predictions were conservative when compared to gas gun test results. The response of the gage will equilibrate within 5% to its final value within 300 {mu}sec. The impulse delivered to the gages for these tests exceeded 250 ktap. The code and experimental results provides a basis for confidence in the operability of the gage in an actual UGT environment.
Date: July 31, 1990
Creator: Rose, P.C. & Naumann, W.J. (General Research Corp., Santa Barbara, CA (USA). Advanced Technologies Div.)
Object Type: Report
System: The UNT Digital Library
Confined vortex scrubber (open access)

Confined vortex scrubber

The program objective is to demonstrate efficient removal of fine particulates to sufficiently low levels to meet proposed small scale coal combustor emission standards using a cleanup technology appropriate to small scale coal combustors. This to be accomplished using a novel particulate removal device, the Confined Vortex Scrubber (CVS), which consists of a cylindrical vortex chamber with tangential flue gas inlets. The clean gas exit is via vortex finder outlets, one at either end of the tube. Liquid is introduced into the chamber and is confined within the vortex chamber by the centrifugal force generated by the gas flow itself. This confined liquid forms a layer through which the flue gas is then forced to bubble, producing a strong gas/liquid interaction, high inertial separation forces and efficient particulate cleanup. During this quarter a comprehensive series of cleanup experiments have been made for three CVS configurations. The first CVS configuration tested gave very efficient fine particulate removal at the design air mass flow rate (1 MM BUT/hr combustor exhaust flow), but had over 20{double prime}WC pressure drop. The first CVS configuration was then re-designed to produce the same very efficient particulate collection performance at a lower pressure drop. The current CVS …
Date: July 1, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Advanced coal-fueled industrial cogeneration gas turbine system (open access)

Advanced coal-fueled industrial cogeneration gas turbine system

The objective of the Solar/METC program is to prove the technical, economic, and environmental feasibility of coal-fired gas turbine for cogeneration applications through tests of a Centaur Type H engine system operated on coal fuel throughout the engine design operating range. This quarter, work was centered on design, fabrication, and testing of the combustor, cleanup, fuel specifications, and hot end simulation rig. 2 refs., 59 figs., 29 tabs.
Date: July 1, 1990
Creator: LeCren, R. T.; Cowell, L. H.; Galica, M. A.; Stephenson, M. D. & Wen, C. S.
Object Type: Report
System: The UNT Digital Library
Duct injection technology prototype development: Evaluation of engineering data (open access)

Duct injection technology prototype development: Evaluation of engineering data

The objective of the Duct Injection Technology Prototype Development Project is to develop a sound design basis for applying duct injection technology as a post-combustion SO{sub 2}emissions control method to existing coal-fired power plants. The necessary engineering design and scale-up criteria will be developed for the commercialization of duct injection technology for the control of SO{sub 2} emissions from coal-fired boilers in the utility industry. The primary focus of the analyses summarized in this Topical Report is the review of the known technical and economic information associated with duct injection technology. (VC)
Date: July 1, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Energy conservation standards for new federal residential buildings: A decision analysis study using relative value discounting (open access)

Energy conservation standards for new federal residential buildings: A decision analysis study using relative value discounting

This report presents a reassessment of the proposed standard for energy conservation in new federal residential buildings. The analysis uses the data presented in the report, Economic Analysis: In Support of Interim Energy Conservation Standards for New Federal Residential Buildings (June 1988)-to be referred to as the EASIECS report. The reassessment differs from that report in several respects. In modeling factual information, it uses more recent forecasts of future energy prices and it uses data from the Bureau of the Census in order to estimate the distribution of lifetimes of residential buildings rather than assuming a hypothetical 25-year lifetime. In modeling social preferences decision analysis techniques are used in order to examine issues of public values that often are not included in traditional cost-benefit analyses. The present report concludes that the public would benefit from the proposed standard. Several issues of public values regarding energy use are illustrated with methods to include them in a formal analysis of a proposed energy policy. The first issue places a value on costs and benefits that will occur in the future as an irreversible consequence of current policy choices. This report discusses an alternative method, called relative value discounting which permits flexible discounting …
Date: July 2, 1990
Creator: Harvey, C. (Houston Univ., TX (USA). Coll. of Business Administration); Merkhofer, M.M. & Hamm, G.L. (Applied Decision Analysis, Inc., Menlo Park, CA (USA))
Object Type: Report
System: The UNT Digital Library
The aluminium-scandium-lithium-magnesium system as a potential source of superplastically formable alloys (open access)

The aluminium-scandium-lithium-magnesium system as a potential source of superplastically formable alloys

Alloys from the aluminum-lithium-scandium-magnesium system have been cast and rolled for study. The goal is to evaluate this system for the development of superplastically formable, high strength alloys. Aluminum-scandium-magnesium alloys have shown potential as superplastic alloys. These alloys rely on small Al{sub 3}Sc (ordered L1{sub 2}) precipitates for grain structure stabilization and strengthening. Additional precipitation strengthening is required to raise their strength to levels sufficient for aircraft applications. The addition of lithium provides this additional strengthening through the formation of Al{sub 3}Li({delta}{prime}). To produce the alloys studied in this research, a unique induction melting furnace was constructed that incorporates special features to produce aluminum-lithium alloys with low hydrogen content. The furnace also features a water cooled, copper casting mold to achieve a moderately rapid solidification rate. This is because the amount of scandium used (0.5 wt %) is in excess of the solubility limit and Al{sub 3}Sc cannot be re-solutionized to any extent. It is therefore desired to super-saturate the matrix with as much scandium as possible for later precipitation. Two high lithium alloys were produced, ALS2 (nominal composition Al-2.2Li-O.5 Sc) and AlS4 (nominal composition Al-2.0Li-2.2Mg-0.5Sc) that were strengthened with {delta}{prime} (Al{sub 3}Li). These alloys exhibited strength and ductility superior …
Date: July 1, 1990
Creator: Emigh, R.A.
Object Type: Report
System: The UNT Digital Library
Swelling and tensile properties of neutron-irradiated vanadium alloys (open access)

Swelling and tensile properties of neutron-irradiated vanadium alloys

Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600{degree}C to neutron fluences ranging from 0.3 to 1.9 {times} 10{sup 27} neutrons/m{sup 2} (17 to 114 atom displacements per atom (dpa)).
Date: July 1, 1990
Creator: Loomis, B. A. & Smith, D. L.
Object Type: Article
System: The UNT Digital Library
Treatment of pulp mill sludges by supercritical water oxidation (open access)

Treatment of pulp mill sludges by supercritical water oxidation

Supercritical water oxidation (SCWO) is new process that can oxidize organics very effectively at moderate temperatures (400 to 650{degree}C) and high pressure (3700 psi). It is an environmentally acceptable alternative for sludge treatment. In bench scale tests, total organic carbon (TOC) and total organic halide (TOX) reductions of 99 to 99.9% were obtained; dioxin reductions were 95 to 99.9%. A conceptual design for commercial systems has been completed and preliminary economics have been estimated. Comparisons confirm that SCWO is less costly than dewatering plus incineration for treating pulp mill sludges. SCWO can also compete effectively with dewatering plus landfilling where tipping fees exceed $35/yd{sup 3}. In some regions of the US, tipping fees are now $75/yd{sup 3} and rising steadily. In the 1995 to 2000 time frame, SCWO has a good chance of becoming the method of choice. MODEC's objective is to bring the technology to commercial availability by 1993. 10 refs., 6 figs., 19 tabs.
Date: July 1, 1990
Creator: Modell, M.
Object Type: Report
System: The UNT Digital Library
Development of standardized air-blown coal gasifier/gas turbine concepts for future electric power systems (open access)

Development of standardized air-blown coal gasifier/gas turbine concepts for future electric power systems

CRS Sirrine (CRSS) is evaluating a novel IGCC process in which gases exiting the gasifier are burned in a gas turbine combustion system. The turbine exhaust gas is used to generate additional power in a conventional steam generator. This results in a significant increase in efficiency. However, the IGCC process requires development of novel approaches to control SO{sub 2} and NO{sub x} emissions and alkali vapors which can damage downstream turbine components. Ammonia is produced from the reaction of coal-bound nitrogen with steam in the reducing zone of any fixed bed coal gasifier. This ammonia can be partially oxidized to NO{sub x} when the product gas is oxidized in a gas turbine combustor. Alkali metals vaporize in the high-temperature combustion zone of the gasifier and laser condense on the surface of small char or ash particles or on cooled metal surfaces. It these alkali-coated materials reach the gas turbine combustor, the alkali will revaporize condense on turbine blades and cause rapid high temperature corrosion. Efficiency reduction will result. PSI Technology Company (PSIT) was contracted by CRSS to evaluate and recommend solutions for NO{sub x} emissions and for alkali metals deposition. Various methods for NO{sub x} emission control and the potential …
Date: July 1, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The extraction of bitumen from western tar sands (open access)

The extraction of bitumen from western tar sands

Topics discussed include: characterization of bitumen impregnated sandstone, water based tar sand separation technology, electrophoretic characterization of bitumen and fine mineral particles, bitumen and tar sand slurry viscosity, the hot water digestion-flotation process, electric field use on breaking water-in-oil emulsions, upgrading of bitumens and bitumen-derived liquids, solvent extraction.
Date: July 1, 1990
Creator: Oblad, A. G.; Bunger, J. W.; Deo, M. D.; Hanson, F. V.; Miller, J. D. & Seader, J. D.
Object Type: Report
System: The UNT Digital Library
ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments (open access)

ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments

The Analytic System and Software for Evaluating Safeguards and Security (ASSESS) has been released for use by DOE field offices and their contractors. In October, 1989, we offered a prototype workshop to selected representatives of the DOE community. Based on the prototype results, we held the first training workshop at the Central Training Academy in January, 1990. Four additional workshops are scheduled for FY 1990. ASSESS is a state-of-the-art analytical tool for management to conduct integrated evaluation of safeguards systems at facilities handling facilities. Currently, ASSESS focuses on the threat of theft/diversion of special nuclear material by insiders, outsiders, and a special form of insider/outsider collusion. ASSESS also includes a neutralization module. Development of the tool is continuing. Plans are underway to expand the capabilities of ASSESS to evaluate against violent insiders, to validate the databases, to expand the neutralization module, and to assist in demonstrating compliance with DOE Material Control and Accountability (MC A) Order 5633.3. These new capabilities include the ability to: compute a weighted average for performance capability against a spectrum of insider adversaries; conduct defense-in-depth analyses; and analyze against protracted theft scenarios. As they become available, these capabilities will be incorporated in our training program. ASSESS …
Date: July 15, 1990
Creator: Al-Ayat, R.A. (Lawrence Livermore National Lab., CA (USA)); Cousins, T.D. (USDOE, Washington, DC (USA)) & Hoover, E.R. (Sandia National Labs., Albuquerque, NM (USA))
Object Type: Article
System: The UNT Digital Library
Diagnostic method for measuring plasma-induced voltages on the PBX-M (Princeton Beta Experiment-Modified) stabilizing shell (open access)

Diagnostic method for measuring plasma-induced voltages on the PBX-M (Princeton Beta Experiment-Modified) stabilizing shell

The Princeton Beta Experiment-Modified (PBX-M) has a close-fitting conducting, passive plate, stabilizing shell which nearly surrounds highly indented, bean-shaped plasmas. The proximity of this electrically isolated shell to a large fraction of the plasma surface allows measurements similar to previous work on other tokamaks using floating probes and limiters. Measurements were performed to characterize the plasma-induced voltages on the PBX-M passive plate stabilizing shell during high-{beta} plasmas. Voltage differences were measured between the respective passive plate toroidal and poloidal gaps, the respective passive plates and the vessel, and an outer poloidal graphite limiter and its passive plate. The calibration and qualification testing procedures are discussed. The initial measurements found that the largest voltages were observed at plasma start-up and at the plasma current disruption and exhibited characteristics depending on operating conditions. The highest voltages observed have been at disruption and were less than 2 kV. 9 refs., 5 figs.
Date: July 1, 1990
Creator: Kugel, H.W.; Okabayashi, M. & Schweitzer, S.
Object Type: Report
System: The UNT Digital Library
The transport properties of activated carbon fibers (open access)

The transport properties of activated carbon fibers

The transport properties of activated isotropic pitch-based carbon fibers with surface area 1000 m{sup 2}/g have been investigated. We report preliminary results on the electrical conductivity, the magnetoresistance, the thermal conductivity and the thermopower of these fibers as a function of temperature. Comparisons are made to transport properties of other disordered carbons. 19 refs., 4 figs.
Date: July 1990
Creator: di Vittorio, S. L.; Dresselhaus, M. S.; Endo, M.; Issi, J.-P. & Piraux, L.
Object Type: Report
System: The UNT Digital Library
Strategy for identifying natural analogs of the long-term performance of low-level waste disposal sites (open access)

Strategy for identifying natural analogs of the long-term performance of low-level waste disposal sites

The US Department of Energy's Low-Level Waste (LLW) Management Program has asked Pacific Northwest Laboratory (PNL) to explore the feasibility of using natural analogs of anticipated waste site and conditions to help validate predictions of the performance of LLW disposal sites. Current regulations require LLW facilities to control the spread of hazardous substances into the environment for at least the next 500 years. Natural analog studies can provide information about processes affecting waste containment that cannot be fully explored through laboratory experimentation and modeling because of the extended period of required performance. For LLW applications, natural analogs include geochemical systems, pedogenic (soil formation) indicators, proxy climate data, and ecological and archaeological settings that portray long-term changes in disposal site environments and the survivability of proposed waste containment materials and structures. Analog data consist of estimates of performance assessment (PA) model input parameters that define possible future environmental states of waste sites, validation parameters that can be predicted by PA models, and descriptive information that can build public confidence in waste disposal practices. This document describes PNL's overall stategy for identifying analogs for LLW disposal systems, reviews lessons learned from past analogs work, outlines the findings of the workshop, and presents …
Date: July 1990
Creator: Chatters, J. C.; Waugh, W. J.; Foley, M. G. & Kincaid, C. T.
Object Type: Report
System: The UNT Digital Library
Interaction region considerations for a B-factory (open access)

Interaction region considerations for a B-factory

The goal of the project is to observe CP violation in the {bar B}B system. This machine is supposed to be a factory for high energy physics, not an R D project for accelerator physics. There are a number of interrelated design issues arising from the different desires of the detector and the machine, some of which are listed in this paper. A number of background and beampipe issues are mentioned. The emphasis is on calculations. Any satisfactory design will combine measurements on existing machines with calculations pertaining to the measurement conditions as well as to the proposed machine. 57 refs.
Date: July 1, 1990
Creator: DeStaebler, H.
Object Type: Article
System: The UNT Digital Library
COSY INFINITY reference manual (open access)

COSY INFINITY reference manual

This is a reference manual for the arbitrary order particle optics and beam dynamics code COSY INFINITY. It is current as of June 28, 1990. COSY INFINITY is a code to study and design particle optical systems, including beamlines, spectrometers, and particle accelerators. At its core it is using differential algebraic (DA) methods, which allow a very systematic and simple calculation of high order effects. At the same time, it allows the computation of dependences on system parameters, which is often interesting in its own right and can also be used for fitting. COSY INFINITY has a full structured object oriented language environment. This provides a simple interface for the casual user. At the same time, it offers the demanding user a very flexible and powerful tool for the study and design of systems, and more generally, the utilization of DA methods. The power and generality of the environment is perhaps best demonstrated by the fact that the physics routines of COSY INFINITY are written in its own input language and are very compact. The approach also considerably facilitates the implementation of new features because they are incorporated with the same commands that are used for design and study. 26 …
Date: July 1, 1990
Creator: Berz, M.
Object Type: Report
System: The UNT Digital Library
Optical properties of flyash (open access)

Optical properties of flyash

The chemical composition and size distribution of representative flyashes are being measured by appropriate microanalytical techniques to provide information required. Measurements of the infrared optical constants (i.e., the complex refractive index m = n - ik) of synthetic slags are being made as a function of wavelength and temperature for controlled compositions. Particular attention will be given to the contribution of the Fe{sub 2}O{sub 3} content and its valence state. The data is being reduced to yield formulae giving the complex refractive index over relevant ranges of wavelength and temperature, as a function of the relevant metal oxide constituents. A benchscale experiment is planned to compare the measured radiant properties of a dispersion of well-characterized ash with computations based on data developed under the first two tasks.
Date: July 1, 1990
Creator: Self, S.A.
Object Type: Report
System: The UNT Digital Library
The production and certification of a plutonium equal-atom reference material: NBL CRM 128 (open access)

The production and certification of a plutonium equal-atom reference material: NBL CRM 128

This report describes the design, production, and certification of the New Brunswick Laboratory plutonium equal-atom certified reference material (CRM), NBL CRM 128. The primary use of this CRM is for the determination of bias corrections encountered in the operation of a mass spectrometer. This reference material is available to the US Department of Energy contractor-operated and government-operated laboratories, as well as to the international nuclear safeguards community. The absolute, or unbiased, certified value for the CRM's Pu-242/Pu-239 ratio is 1.00063 {plus minus} 0.00026 (95% confidence interval) as of October 1, 1984. This value was obtained through the quantitative blending of high-purity, chemically and isotopically characterized separated isotopes, as well as through intercomparisons of CRM samples with calibration mixtures using thermal ionization mass spectrometry. 32 tabs.
Date: July 1, 1990
Creator: Crawford, D.W. (Department of Energy, Washington, DC (USA). Office of Safeguards and Security); Gradle, C.G. & Soriano, M.D. (USDOE New Brunswick Lab., Argonne, IL (USA))
Object Type: Report
System: The UNT Digital Library
Beryllium pressure vessels for creep tests in magnetic fusion energy (open access)

Beryllium pressure vessels for creep tests in magnetic fusion energy

Beryllium has interesting applications in magnetic fusion experimental machines and future power-producing fusion reactors. Chief among the properties of beryllium that make these applications possible is its ability to act as a neutron multiplier, thereby increasing the tritium breeding ability of energy conversion blankets. Another property, the behavior of beryllium in a 14-MeV neutron environment, has not been fully investigated, nor has the creep behavior of beryllium been studied in an energetic neutron flux at thermodynamically interesting temperatures. This small beryllium pressure vessel could be charged with gas to test pressures around 3, 000 psi to produce stress in the metal of 15,000 to 20,000 psi. Such stress levels are typical of those that might be reached in fusion blanket applications of beryllium. After contacting R. Powell at HEDL about including some of the pressure vessels in future test programs, we sent one sample pressure vessel with a pressurizing tube attached (Fig. 1) for burst tests so the quality of the diffusion bond joints could be evaluated. The gas used was helium. Unfortunately, budget restrictions did not permit us to proceed in the creep test program. The purpose of this engineering note is to document the lessons learned to date, …
Date: July 20, 1990
Creator: Neef, W.S.
Object Type: Report
System: The UNT Digital Library
Progress report of a research program in experimental high energy physics (open access)

Progress report of a research program in experimental high energy physics

An experimental program in strong and electro-weak interaction physics of elementary particles is being carried out using electronic detection techniques. Experiments have been performed at Brown, Brookhaven, and Fermilab. The work described in this report by the Electronic Detector Group addresses the following: neutrino interactions and intrinsic properties, preparations for experiments ( D--ZERO'') at the FNAL 2 TeV {bar p}p Collider, new detection techniques for neutrino properties.
Date: July 1, 1990
Creator: Lanou, R.E. Jr. & Cutts, D.
Object Type: Report
System: The UNT Digital Library
Phase 1 of the Hanford Environmental Dose Reconstruction Project (open access)

Phase 1 of the Hanford Environmental Dose Reconstruction Project

This report summarizes the water pathway portion of the first phase of the Hanford Environmental Dose Reconstruction (HEDR) Project, conducted by Battelle staff at the Pacific Northwest Laboratory under the direction of an independent Technical Steering Panel. The HEDR Project is estimating radiation doses that could have been received by the public from the Department of Energy's Hanford Site, in southeastern Washington State. Phase 1 of the water-pathway dose reconstruction sought to determine whether dose estimates could be calculated for populations in the area from above the Hanford Site at Priest Rapids Dam to below the site at McNary Dam from January 1964 to December 1966. Of the potential sources of radionuclides from the river, fish consumption was the most important. Later phases of the HEDR Project will address dose estimates for periods other than 1964--1966 and for populations downstream of McNary Dam. 17 refs., 20 figs., 1 tab.
Date: July 20, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library