Study of intermittency in e sup + e sup minus annihilations at 29 GeV (open access)

Study of intermittency in e sup + e sup minus annihilations at 29 GeV

Charged particle multiplicity distributions from e{sup +}e{sup {minus}} annihilations at 29 GeV have been analyzed in selected rapidity and azimuthal angle intervals. The data were taken with the High Resolution Spectrometer at PEP. The factorial moments of the multiplicity distributions increase as the rapidity interval is decreased, the so-called intermittency phenomenon. These direct measurements of the moments agree with values derived from negative binomial fits to our multiplicity distributions in various central rapidity windows. The factorial moments are also given for the distribution in azimuthal angle around the beam direction and for the two-dimensional distribution in rapidity and azimuthal angle around the jet directions.
Date: June 15, 1990
Creator: Abachi, S.; Derrick, M.; Kooijman, P.; Musgrave, B.; Price, L.; Repond, J. et al.
Object Type: Article
System: The UNT Digital Library
Study of electron-positron interactions (open access)

Study of electron-positron interactions

For the past seven years, this group has been interested in the study of tests of the Standard Model of Electroweak interactions. The program has centered about the AMY experiment which examines the nature of the final state products in electron-positron collisions in the center of mass energy range near 60 GeV. Results of these measurements have shown a remarkable consistency with the predictions of the minimal model of 3 quark and lepton generations and single charged and neutral intermediate bosons. No new particles or excited states have been observed nor has any evidence for departures in cross sections or angular asymmetries from expectations been observed. These conclusions have been even more firmly established by the higher energy results from the LEP and SLC colliders at center of mass energies of about 90 GeV. Our focus is shifting to the neutrino as a probe to electroweak interactions. The relative merit of attempting to observe neutrinos from point sources versus observing neutrinos generally is not easy to predict. The improved ability to interpret is offset by the probably episodic nature of the emission and irreproducibility of the results. In this phase of development, it is best to be sensitive to both …
Date: September 15, 1990
Creator: Abashian, A.; Gotow, K. & Philonen, L.
Object Type: Report
System: The UNT Digital Library
A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions (open access)

A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions

We report on the results of a search for the B{sub c} (b{bar c}) meson in the decay B{sub c}{sup +-} {yields} J/{psi} + {pi}{sup +-}. This search is guided by a control sample of decays of B{sub u} mesons to J/{psi} + K and uses {approx_equal} 75pb{sup -1} of data collected at the Collider Detector Facility (CDF) at Fermilab. The lifetime of the B{sub c} meson is unknown, so the 95% confidence level limit on {sigma} {center_dot} BR(B{sub c} {yields} {psi} + {pi})/{sigma} {center_dot} BR(B{sub u} {yields} {psi} + K) is obtained as a function of the B{sub c} lifetime.
Date: July 15, 1995
Creator: Abe, F.
Object Type: Article
System: The UNT Digital Library
Measurement of the B{sup {minus}} and {bar B}{sup 0} meson lifetimes using semileptonic decays (open access)

Measurement of the B{sup {minus}} and {bar B}{sup 0} meson lifetimes using semileptonic decays

The lifetimes of the B{sup {minus}} and {bar B}{sup 0} mesons are measured using the partially reconstructed semileptonic decays in the CDF experiment.
Date: July 15, 1995
Creator: Abe, F.
Object Type: Report
System: The UNT Digital Library
Optimizing the Turbo-Roto-Compound (TRC) Engine. Final report (open access)

Optimizing the Turbo-Roto-Compound (TRC) Engine. Final report

Results of multidimensional computations of sprays in a very high pressure constant volume chamber are presented in two parts. Comparisons of computed and measured penetrations of non-vaporizing and vaporizing sprays are presented. A broad range of density ratios (0.005 to 0.243) is covered. It is shown that, provided sufficient numerical resolution is used, the model can adequately reproduce the measurements. Scaling laws for time and distance derived in a previous publication are found to apply also to the sprays over the broad range of density ratios considered. A combustion sub-model that has been used in spark-ignition engines, stratified-charge engines and Diesel engines is included in the model. The combustion sub-model represents low-temperature autoignition and high temperature heat release. Comparisons of computed and measured penetrations of combusting sprays and computed and measured chamber pressures are being made. In this report, only preliminary indicative comparisons of computed and measured chamber pressures for three cases are presented. Agreement of pressures within 5% is shown. The work is ongoing and a detailed report will be presented later.
Date: August 15, 1994
Creator: Abraham, J.
Object Type: Report
System: The UNT Digital Library
Report of Foreign Research Assignment for M. M. Abraham, October 1989-September 1990 (open access)

Report of Foreign Research Assignment for M. M. Abraham, October 1989-September 1990

The traveler collaborated with M.J.M. Leask, J.M. Baker, B. Bleaney, and others at the Clarendon Laboratory, Oxford University, Oxford, UK, to Study Tetragonal rare-earth phosphates and vanadates by optical and magnetic spectroscopy. This work is related to similar studies that have been performed at ORNL by the Synthesis and Properties of Novel Materials Group in the Solid State Division.
Date: October 15, 1990
Creator: Abraham, M. M.
Object Type: Report
System: The UNT Digital Library
Oxidation of K-West Basin Spent Nuclear Fuel in Moist Helium Atmosphere (open access)

Oxidation of K-West Basin Spent Nuclear Fuel in Moist Helium Atmosphere

None
Date: June 15, 1999
Creator: Abrefah, J. & Sell, R. L.
Object Type: Report
System: The UNT Digital Library
A hybrid vehicle evaluation code and its application to vehicle design (open access)

A hybrid vehicle evaluation code and its application to vehicle design

This report describes a hybrid vehicle simulation model, which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates interactively, with all the vehicle information stored in data files. The code calculates fuel economy for three driving schedules, time for 0-96 km/h at maximum acceleration, hill climbing performance, power train dimensions, and pollution generation rates. This report also documents the application of the code to a hybrid vehicle that operates with a hydrogen internal combustion engine. The simulation model is used for parametric studies of the vehicle. The results show the fuel economy of the vehicle as a function of vehicle mass, aerodynamic drag, engine-generator efficiency, flywheel efficiency, and flywheel energy and power capacities.
Date: July 15, 1994
Creator: Aceves, S. M. & Smith, J. R.
Object Type: Article
System: The UNT Digital Library
A hybrid vehicle evaluation code and its application to vehicle design. Revision 1 (open access)

A hybrid vehicle evaluation code and its application to vehicle design. Revision 1

This paper describes a hybrid vehicle simulation model which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates in batch mode with all the vehicle information stored in data files. The code calculates fuel economy for three driving schedules, time for 0--96 km/h at maximum acceleration, hill climbing performance, power train dimensions, and pollution generation rates. This paper also documents the application of the code to a hybrid vehicle that utilizes a hydrogen internal combustion engine. The simulation model is used for parametric studies of the vehicle. The results show the fuel economy of the vehicle as a function of vehicle mass, aerodynamic drag, engine efficiency, accessory load, and flywheel efficiency. The code also calculates the minimum flywheel energy and power to obtain a desired performance. The hydrogen hybrid vehicle analyzed in the paper has a predicted range of 480 km (300 miles), with a gasoline equivalent fuel efficiency of 34.2 km/liter (80.9 mpg).
Date: September 15, 1994
Creator: Aceves, S. M. & Smith, J. R.
Object Type: Article
System: The UNT Digital Library
Quantitative non-destructive evaluation of high-temperature superconducting materials (open access)

Quantitative non-destructive evaluation of high-temperature superconducting materials

Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.
Date: September 15, 1990
Creator: Achenbach, J. D.
Object Type: Report
System: The UNT Digital Library
Quantitative non-destructive evaluation of high-temperature superconducting materials. Technical progress report, September 1, 1989--August 30, 1990 (open access)

Quantitative non-destructive evaluation of high-temperature superconducting materials. Technical progress report, September 1, 1989--August 30, 1990

Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.
Date: September 15, 1990
Creator: Achenbach, J. D.
Object Type: Report
System: The UNT Digital Library
Turbine-generator set development for power generation (open access)

Turbine-generator set development for power generation

The goal of this effort was to design, develop, and demonstrate an integrated turbine genset suitable for the power generation requirements of a hybrid automotive propulsion system. The result of this effort would have been prototype generator hardware including controllers for testing and evaluation by Allison Engine Company. The generator would have been coupled to a suitably sized and configured gas turbine engine, which would operate on a laboratory load bank. This effort could lead to extensive knowledge and design capability in the most efficient generator design for hybrid electric vehicle power generation and potentially to commercialization of these advanced technologies. Through the use of the high-speed turbines as a power source for the hybrid-electric vehicles, a significant reduction in nitrous oxides emissions would be achieved when compared to those of conventional gas powered vehicles.
Date: April 15, 1997
Creator: Adams, D.J. & Berenyi, S.G.
Object Type: Report
System: The UNT Digital Library
Biological Monitoring Program for East Fork Poplar Creek (open access)

Biological Monitoring Program for East Fork Poplar Creek

In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biologicai Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the compiex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity …
Date: October 15, 1998
Creator: Adams, S. M.; Christensen, S. W.; Greeley, M. S. Jr.; Hill, W. R.; Kszos, L. A.; McCarthy, J. F. et al.
Object Type: Report
System: The UNT Digital Library
Magnetic correlations in doped transition metal oxides (open access)

Magnetic correlations in doped transition metal oxides

The authors review recent reactor- and spallation-source-based neutron scattering experiments on the magnetic fluctuations and order in a variety of doped transition metal oxides. In particular, data are shown for the NiO chain compound, Y{sub 2{minus}x}Ca{sub x}BaNiO{sub 5}, the two-dimensional cuprate superconductors La{sub 2{minus}x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3} O{sub 6+x}, and the classical three-dimensional ``Mott-Hubbard`` system V{sub 2{minus}y}O{sub 3}.
Date: February 15, 1995
Creator: Aeppli, G.; Bao, W. & Broholm, C.
Object Type: Article
System: The UNT Digital Library
Gamma-ray optical counterpart search experiment (GROCSE) (open access)

Gamma-ray optical counterpart search experiment (GROCSE)

The requirements of a gamma-ray burst optical counterpart detector are reviewed. By taking advantage of real-time notification of bursts, new instruments can make sensitive searches while the gamma-ray transient is still in progress. A wide field of view camera at Livermore National Laboratories has recently been adapted for detecting GRB optical counterparts to a limiting magnitude of 8. A more sensitive camera, capable of reaching m{sub upsilon} = 14, is under development.
Date: December 15, 1993
Creator: Akerlof, C.; Fatuzzo, M.; Lee, B.; Bionta, R.; Ledebuhr, A.; Park, H. S. et al.
Object Type: Article
System: The UNT Digital Library
Operability test report for core sample truck {number_sign}1 flammable gas modifications (open access)

Operability test report for core sample truck {number_sign}1 flammable gas modifications

This report primarily consists of the original test procedure used for the Operability Testing of the flammable gas modifications to Core Sample Truck No. One. Included are exceptions, resolutions, comments, and test results. This report consists of the original, completed, test procedure used for the Operability Testing of the flammable gas modifications to the Push Mode Core Sample Truck No. 1. Prior to the Acceptance/Operability test the truck No. 1 operations procedure (TO-080-503) was revised to be more consistent with the other core sample truck procedures and to include operational steps/instructions for the SR weather cover pressurization system. A draft copy of the operations procedure was used to perform the Operability Test Procedure (OTP). A Document Acceptance Review Form is included with this report (last page) indicating the draft status of the operations procedure during the OTP. During the OTP 11 test exceptions were encountered. Of these exceptions four were determined to affect Acceptance Criteria as listed in the OTP, Section 4.7 ACCEPTANCE CRITERIA.
Date: September 15, 1997
Creator: Akers, J.C.
Object Type: Report
System: The UNT Digital Library
Proton Decay Studies of the Light Lu, Tm and Ho Isotopes (open access)

Proton Decay Studies of the Light Lu, Tm and Ho Isotopes

A double-sided Si-strip detector system has been installed and commissioned at the focal plane of the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. The system can be used for heavy charged particle emission studies with half-lives as low as a few {micro}sec. In this paper the authors present identification and study of the decay properties of the five new proton emitters: {sup 140}Ho, {sup 141m}Ho, {sup 145}Tm, {sup 150m}Lu and {sup 151m}Lu.
Date: October 15, 1998
Creator: Akovali, Y.; Batchelder, J. C.; Bingham, C. R.; Davinson, T.; Ginter, T. N.; Gross, C. J. et al.
Object Type: Article
System: The UNT Digital Library
Investigation of syngas interactions in alcohol synthesis catalyst (open access)

Investigation of syngas interactions in alcohol synthesis catalyst

The primary objectives of the project are to (a) synthesize, by controlled sequential and co-impregnation techniques, three distinct composition metal clusters (consisting of Cu-Co-Cr and Cu-Fe-Zn): rich in copper (Methanol selective), rich in ferromagnetic metal (Co or Fe-Hydrocarbon selective) and intermediate range (mixed alcohol catalysts); (b) investigate the changes in the magnetic character of the systems due to interaction with CO, through Zero-field Nuclear Magnetic Resonance (ZFNMR) study of cobalt and Magnetic character (saturation magnetization and coercive field) analysis of the composite catalyst of Vibrating Sample Magnetometry (VSM); (c) examine the changes in syngas adsorption character of the catalyst as the composition changes, by FTIR Spectroscopic analysis of CO stretching frequencies; (d) determine the nature and size of these intermetallic clusters by Scanning Electron Microscopy (SEM); and (e) perform catalytic runs on selected samples and analyze the correlations between the physical and chemical characteristics. The catalysts chosen have a greater promise for industrial application than the Rh and Mo based catalysts. Several groups preparing catalysts by synthetic routes have reported divergent results for activity and selectivity. Generally the research has followed an empirical path and less effort is devoted to analyze the mechanisms and the scientific basis. The primary intent …
Date: April 15, 1998
Creator: Akundi, M. A.
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
A preliminary study of extraction solvents for CW-agents and their decomposition products [3:1 (methylene chloride:isopropanol) vs. methylene chloride] (open access)

A preliminary study of extraction solvents for CW-agents and their decomposition products [3:1 (methylene chloride:isopropanol) vs. methylene chloride]

The major focus of this study was to explore the possibility of using different extraction solvents (or solvent combinations) to isolate CW agents and their degradation products from environmental and industrial samples. The general approach for extracting, e.g. water samples, required the use of a 3:1 (methylene chloride:isopropanol) extraction solvent. Although the 3:1 solvent extraction work-up methods provided excellent results in several Inter-laboratory Comparison Tests, the implementation of these methods for CW on-site analysis exercises was difficult (the methods require cumbersome equipment and are labor intensive). However, due to the time, power, and size restraints set forth by the Chemical Warfare Convention (CWC) for a CW on-site inspection, LLNL developed new sample work-up methods. The approach selected by LLNL incorporated solid phase extraction (SPE) techniques. It is evident from this preliminary study that new or previously used extraction solvents should be re-investigated. It was determined that care must be taken in handling the samples prior to NMR measurements. Also, it was determined that the four target compounds used in this study were extracted on average 18% higher with 3:1 (CH{sub 2}Cl{sub 2}: IPA) vs. CH{sub 2}Cl{sub 2}. However, additional target compounds need to be investigated using this extraction solvent to …
Date: September 15, 1994
Creator: Alcaraz, A.; Ward, R. L.; Hulsey, S. S. & Andresen, B. D.
Object Type: Report
System: The UNT Digital Library
ALPS - advanced limiter-divertor plasma-facing systems. (open access)

ALPS - advanced limiter-divertor plasma-facing systems.

The Advanced Limiter-divertor Plasma-facing Systems (ALPS) program was initiated in order to evaluate the potential for improved performance and lifetime for plasma-facing systems. The main goal of the program is to demonstrate the advantages of advanced limiter/divertor systems over conventional systems in terms of power density capability, component lifetime, and power conversion efficiency, while providing for safe operation and minimizing impurity concerns for the plasma. Most of the work to date has been applied to free surface liquids. A multi-disciplinary team from several institutions has been organized to address the key issues associated with these systems. The main performance goals for advanced limiters and diverters are a peak heat flux of >50 MW/m{sup 2},elimination of a lifetime limit for erosion, and the ability to extract useful heat at high power conversion efficiency ({approximately}40%). The evaluation of various options is being conducted through a combination of laboratory experiments, modeling of key processes, and conceptual design studies. The current emphasis for the work is on the effects of free surface liquids on plasma edge performance.
Date: September 15, 1999
Creator: Allain, J. P.; Bastasz, R.; Brooks, J. N.; Evans, T.; Hassanein, A.; Luckhardt, S. et al.
Object Type: Article
System: The UNT Digital Library
Sorption and diffusion studies of Pu(IV) and Pu(V)-EDTA onto and through Hanford soil (open access)

Sorption and diffusion studies of Pu(IV) and Pu(V)-EDTA onto and through Hanford soil

Plutonium production at U.S. Department of Energy Hanford site has created massive amounts of radioactive and mixed wastes. Over 1.3 trillion liters of liquid waste have been discharged into the ground, the largest part of which has been absorbed by the upper soil layers with a small fraction migrating into the groundwater. Approximately 350 million liters of other low and high-level mixed wastes were stored in underground tanks between 1944 and 1980. These tanks contain organic materials that were introduced during the production and processing of plutonium, such as ethylenediametetraacetic acid (EDTA), tributyl phosphate, hexone, paraffin hydrocarbon and other minor organic and inorganic components. The quantity of EDTA is estimated to be 83 metric tons in the underground tanks. Several single-shell tanks are known or suspected to have leaked. It was reported that since 1995, approximately four million liters of mixed waste might have entered the soil beneath the single-shell tanks. This volume of waste is estimated to contain as much as one million curies of radioactivity.
Date: September 15, 1999
Creator: Allen, P G; Hakem, N L & Sylwester, E R
Object Type: Article
System: The UNT Digital Library
Origin of the Time-Dependence of Wet Oxidation of AlGaAs (open access)

Origin of the Time-Dependence of Wet Oxidation of AlGaAs

The time-dependence of the wet oxidation of high-Al-content AlGaAs can be either linear, indicating reaction-rate limitation, or parabolic, indicating diffusion-limited rates. The transition from linear to parabolic time dependence can be explained by the increased rate of the formation of intermediate As{sub 2}O{sub 3} vs. its reduction to elemental As. A steadily increasing thickness of the As{sub 2}O{sub 3}-containing region at the oxidation front will shift the process from the linear to the parabolic regime. This shift from reaction-rate-limited (linear) to diffusion-limited (parabolic) time dependence is favored by increasing temperature or increasing Al mole fraction.
Date: February 15, 1999
Creator: Allerman, A. A.; Ashby, C. I. H.; Bridges, M. M.; Hammons, B. E. & Hou, H. Q.
Object Type: Article
System: The UNT Digital Library
GaAs Self-Aligned JFETS with Carbon-Doped P+ Region (open access)

GaAs Self-Aligned JFETS with Carbon-Doped P+ Region

Self-aligned JFETs with a carbon-doped p{sup +} region have been reported for the first time. For these JFETs, both the channel and p{sup +} region were grown by metal organic chemical vapor deposition (MOCVD) and are termed epitaxial JFETs in this study. The epitaxial JFETs were compared to ion implanted JFETs of similar channel doping and threshold voltage. Both JFETs were fabricated using the same self-aligned process for doping the source and drain regions of the JFET and for eliminating excess gate capacitance of conventional JFETs. The gate turn-on voltage for the epitaxial JFETs was 1.06 V, about 0.1 V higher than for the implanted JFETs. The reverse breakdown voltage was similar for both JFETs but the reverse gate leakage current of the epitaxial JFETs was 1-3 orders of magnitude less than the implanted JFETs. The epitaxial JFETs also showed higher transconductance and lower knee voltage than the implanted JFETs.
Date: February 15, 1999
Creator: Allerman, A. A.; Baca, A. G.; Chang, P. C. & Drummond, T. J.
Object Type: Article
System: The UNT Digital Library