A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback (open access)

A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback

A 4.2 GS/sec. beam excitation system with accelerator synchronization and power stages is described. The system is capable of playing unique samples (32 samples/bunch) for 15,000 turns on selected bunch(es) in the SPS in syn- chronism with the injection and acceleration cycle. The purpose of the system is to excite internal modes of single-bunch vertical motion, and study the bunch dynamics in the presence of developing Electron cloud or TMCI effects. The system includes a synchronized master oscillator, SPS timing functions, an FPGA based arbitrary waveform generator, 4.2 GS/sec. D/A system and four 80W 20-1000 MHz amplifiers driving a tapered stripline pickup/kicker. A software GUI allows specification of various modulation signals, selection of bunches and turns to excite, while a remote control interface allows simple control/monitoring of the RF power stages located in the tunnel. The successful use of this system for SPS MD measurements in 2011 is a vital proof-of-principle for wideband feedback using similar functions to correct the beam motion.
Date: July 10, 2012
Creator: Fox, John
Object Type: Article
System: The UNT Digital Library
12 GeV Upgrade Project - Cryomodule Production (open access)

12 GeV Upgrade Project - Cryomodule Production

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is producing ten 100+MV SRF cryomodules (C100) as part of the CEBAF 12 GeV Upgrade Project. Once installed, these cryomodules will become part of an integrated accelerator system upgrade that will result in doubling the energy of the CEBAF machine from 6 to 12 GeV. This paper will present a complete overview of the C100 cryomodule production process. The C100 cryomodule was designed to have the major components procured from private industry and assembled together at Jefferson Lab. In addition to measuring the integrated component performance, the performance of the individual components is verified prior to being released for production and assembly into a cryomodule. Following a comprehensive cold acceptance test of all subsystems, the completed C100 cryomodules are installed and commissioned in the CEBAF machine in preparation of accelerator operations. This overview of the cryomodule production process will include all principal performance measurements, acceptance criterion and up to date status of current activities.
Date: July 1, 2012
Creator: J. Hogan, A. Burrill, G.K. Davis, M.A. Drury, M. Wiseman
Object Type: Article
System: The UNT Digital Library
A 12 GHz RF Power Source for the CLIC Study (open access)

A 12 GHz RF Power Source for the CLIC Study

The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for CLIC accelerating structure testing. A design and fabrication contract for five klystrons at that frequency has been signed by different parties with SLAC. France (IRFU, CEA Saclay) is contributing a solid state modulator purchased in industry and specific 12 GHz RF network components to the CLIC study. RF pulses over 120 MW peak at 230 ns length will be obtained by using a novel SLED-I type pulse compression scheme designed and fabricated by IAP, Nizhny Novgorod, Russia. The X-band power test stand is being installed in the CLIC Test Facility CTF3 for independent structure and component testing in a bunker, but allowing, in a later stage, for powering RF components in the CTF3 beam lines. The design of the facility, results from commissioning of the RF power source and the expected performance of the Test Facility are reported.
Date: July 3, 2012
Creator: Schirm, Karl; Curt, Stephane; Dobert, Steffen; McMonagle, Gerard; Rossat, Ghislain; Syratchev, Igor et al.
Object Type: Article
System: The UNT Digital Library
A 14 MeV Fusion Neutron Source for Material and Blanket Development and Fission Fuel Production (open access)

A 14 MeV Fusion Neutron Source for Material and Blanket Development and Fission Fuel Production

None
Date: July 30, 2012
Creator: Simonen, T. C.; Moir, R. W.; Molvik, A. W. & Ryutov, D. D.
Object Type: Article
System: The UNT Digital Library
50% Advanced Energy Design Guides: Preprint (open access)

50% Advanced Energy Design Guides: Preprint

This paper presents the process, methodology, and assumptions for the development of the 50% Energy Savings Advanced Energy Design Guides (AEDGs), a design guidance document that provides specific recommendations for achieving 50% energy savings above the requirements of ANSI/ASHRAE/IESNA Standard 90.1-2004 in four building types: (1) Small to medium office buildings, (2) K-12 school buildings, (3) Medium to big box retail buildings, (4) Large hospital buildings.
Date: July 1, 2012
Creator: Bonnema, E.; Leach, M.; Pless, S.; Liu, B.; Wang, W.; Thornton, B. et al.
Object Type: Article
System: The UNT Digital Library
500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application (open access)

500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This …
Date: July 3, 2012
Creator: Chu, Tak Sum; Anderson, Scott; Barty, Christopher; Gibson, David; Hartemann, Fred; Marsh, Roark et al.
Object Type: Article
System: The UNT Digital Library
2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012 (open access)

2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012

At the 2012 Atomic and Molecular Interactions Gordon Conference, there will be talks in several broadly defined and partially overlapping areas:  Intramolecular and single-collision reaction dynamics;  Photophysics and photochemistry of excited states;  Clusters, aerosols and solvation;  Interactions at interfaces;  Conformations and folding of large molecules;  Interactions under extreme conditions of temperature and pressure. The theme of the Gordon Research Seminar on Atomic & Molecular Interactions, in keeping with the tradition of the Atomic and Molecular Interactions Gordon Research Conference, is far-reaching and involves fundamental research in the gas and condensed phases along with application of these ideas to practical chemical fields. The oral presentations, which will contain a combination of both experiment and theory, will focus on four broad categories:  Ultrafast Phenomena;  Excited States, Photoelectrons, and Photoions;  Chemical Reaction Dynamics;  Biomolecules and Clusters.
Date: July 20, 2012
Creator: Zwier, Timothy
Object Type: Article
System: The UNT Digital Library
2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012 (open access)

2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012

Topics covered in this GRC include high-resolution spectroscopy, coherent electronic energy transport in biology, excited state theory and dynamics, excitonics, electronic spectroscopy of cold and ultracold molecules, and the spectroscopy of nanostructures. Several sessions will highlight innovative techniques such as time-resolved x-ray spectroscopy, frequency combs, and liquid microjet photoelectron spectroscopy that have forged stimulating new connections between gas-phase and condensed-phase work.
Date: July 27, 2012
Creator: Kohler, Bern
Object Type: Article
System: The UNT Digital Library
2012 MICROBIAL STRESS RESPONSE GORDON RESEARCH CONFERENCE, JULY 20-25, 2012 (open access)

2012 MICROBIAL STRESS RESPONSE GORDON RESEARCH CONFERENCE, JULY 20-25, 2012

The Gordon Research Conference on MICROBIAL STRESS RESPONSE was held at Mount Holyoke College, South Hadley, Massachusetts, July 15-20, 2012. The Conference was well-attended with 180 participants. The 2012 Microbial Stress Responses Gordon Research Conference will provide a forum for the open reporting of recent discoveries on the diverse mechanisms employed by microbes to respond to stress. Approaches range from analysis at the molecular level (how are signals perceived and transmitted to change gene expression or function) to cellular and microbial community responses. Gordon Research Conferences does not permit publication of meeting proceedings.
Date: July 25, 2012
Creator: Donohue, Timothy
Object Type: Article
System: The UNT Digital Library
2012 ORGANOMETALLIC CHEMISTRY GRC/GRS, JULY 7-13, 2012 (open access)

2012 ORGANOMETALLIC CHEMISTRY GRC/GRS, JULY 7-13, 2012

The 2012 Organometallic Chemistry Gordon Research Conference will highlight new basic science and fundamental applications of organometallic chemistry in industrial, academic, and national lab settings. Scientific themes of the conference will include chemical synthesis, reactivity, catalysis, polymer chemistry, bonding, and theory that involve transition-metal (and main-group) interactions with organic moieties.
Date: July 13, 2012
Creator: Hillhouse, Gregory
Object Type: Article
System: The UNT Digital Library
2012 PHOTOSYNTHESIS GORDON RESEARCH CONFERENCE AND SEMINAR, JUL 7-13, 2012 (open access)

2012 PHOTOSYNTHESIS GORDON RESEARCH CONFERENCE AND SEMINAR, JUL 7-13, 2012

The Gordon Research Conference on PHOTOSYNTHESIS was held at Davidson College, Davidson, North Carolina, July 8 ? 13, 2012. The Conference was well-attended with 150 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 150 attendees, 65 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 65 respondents, 20% were Minorities ? 5% Hispanic, 15% Asian and 0% African American. Approximately 28% of the participants at the 2012 meeting were women. The Gordon Research Seminar on PHOTOSYNTHESIS held at Davidson College, Davidson, North Carolina, July 7-8, 2012.. The Conference was well-attended with 51 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 51 attendees, 22 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 22 respondents, 14% were Minorities ? 0% Hispanic, 14% Asian and 0% African American. Approximately 35% of the participants at the 2012 …
Date: July 13, 2012
Creator: Debus, Richard
Object Type: Article
System: The UNT Digital Library
2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012 (open access)

2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012

The mechanical behavior of materials with small dimension(s) is of both fundamental scientific interest and technological relevance. The size effects and novel properties that arise from changes in deformation mechanism have important implications for modern technologies such as thin films for microelectronics and MEMS devices, thermal and tribological coatings, materials for energy production and advanced batteries, etc. The overarching goal of the 2012 Gordon Research Conference on "Thin Film and Small Scale Mechanical Behavior" is to discuss recent studies and future opportunities regarding elastic, plastic and time-dependent deformation, as well as degradation and failure mechanisms such as fatigue, fracture and wear. Specific topics of interest include, but are not limited to: fundamental studies of physical mechanisms governing small-scale mechanical behavior; advances in test techniques for materials at small length scales, such as nanotribology and high-temperature nanoindentation; in-situ mechanical testing and characterization; nanomechanics of battery materials, such as swelling-induced phenomena and chemomechanical behavior; flexible electronics; mechanical properties of graphene and carbon-based materials; mechanical behavior of small-scale biological structures and biomimetic materials. Both experimental and computational work will be included in the oral and poster presentations at this Conference.
Date: July 27, 2012
Creator: Balk, Thomas
Object Type: Article
System: The UNT Digital Library
Accelerator R&D: Research for Science - Science for Society (open access)

Accelerator R&D: Research for Science - Science for Society

In September 2011 the US Senate Appropriations Committee requested a ten-year strategic plan from the Department of Energy (DOE) that would describe how accelerator R&D today could advance applications directly relevant to society. Based on the 2009 workshop 'Accelerators for America's Future' an assessment was made on how accelerator technology developed by the nation's laboratories and universities could directly translate into a competitive strength for industrial partners and a variety of government agencies in the research, defense and national security sectors. The Office of High Energy Physics, traditionally the steward for advanced accelerator R&D within DOE, commissioned a task force under its auspices to generate and compile ideas on how best to implement strategies that would help fulfill the needs of industry and other agencies, while maintaining focus on its core mission of fundamental science investigation.
Date: July 2012
Creator: Holtkamp, N.; Biedron, S.; Boeh, L.; Clayton, J.; Gourlay, S.; Hamm, R. et al.
Object Type: Article
System: The UNT Digital Library
Active-Interrogation Measurements of Induced-Fission Neutrons from Low-Enriched Uranium (open access)

Active-Interrogation Measurements of Induced-Fission Neutrons from Low-Enriched Uranium

Protection and control of nuclear fuels is paramount for nuclear security and safeguards; therefore, it is important to develop fast and robust controlling mechanisms to ensure the safety of nuclear fuels. Through both passive- and active-interrogation methods we can use fast-neutron detection to perform real-time measurements of fission neutrons for process monitoring. Active interrogation allows us to use different ranges of incident neutron energy to probe for different isotopes of uranium. With fast-neutron detectors, such as organic liquid scintillation detectors, we can detect the induced-fission neutrons and photons and work towards quantifying a sample’s mass and enrichment. Using MCNPX-PoliMi, a system was designed to measure induced-fission neutrons from U-235 and U-238. Measurements were then performed in the summer of 2010 at the Joint Research Centre in Ispra, Italy. Fissions were induced with an associated particle D-T generator and an isotopic Am-Li source. The fission neutrons, as well as neutrons from (n, 2n) and (n, 3n) reactions, were measured with five 5” by 5” EJ-309 organic liquid scintillators. The D-T neutron generator was available as part of a measurement campaign in place by Padova University. The measurement and data-acquisition systems were developed at the University of Michigan utilizing a CAEN V1720 …
Date: July 1, 2012
Creator: Dolan, J. L.; Marcath, M. J.; Flaska, M.; Pozzi, S. A.; Chichester, D. L.; Tomanin, A. et al.
Object Type: Article
System: The UNT Digital Library
ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE (open access)

ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE

In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate Enhanced Chemical Cleaning (ECC), an alternative to the baseline 8 wt% oxalic acid (OA) chemical cleaning technology for tank sludge heel removal. ECC utilizes a more dilute OA solution (2 wt%) and an oxalate destruction technology using ozonolysis with or without the application of ultraviolet (UV) light. SRNL conducted tests of the ECC process using actual SRS waste material from Tanks 5F and 12H. The previous phase of testing involved testing of all phases of the ECC process (sludge dissolution, OA decomposition, product evaporation, and deposition tank storage) but did not involve the use of UV light in OA decomposition. The new phase of testing documented in this report focused on the use of UV light to assist OA decomposition, but involved only the OA decomposition and deposition tank portions of the process. Compared with the previous testing at analogous conditions without UV light, OA decomposition with the use of UV light generally reduced time required to reach the target of <100 mg/L oxalate. This effect was the most pronounced during the initial part of the decomposition …
Date: July 10, 2012
Creator: Martino, C.; King, W. & Ketusky, E.
Object Type: Report
System: The UNT Digital Library
Advanced X-Band Test Accelerator for High Brightness Electron and Gamma Ray Beams (open access)

Advanced X-Band Test Accelerator for High Brightness Electron and Gamma Ray Beams

In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.
Date: July 3, 2012
Creator: Marsh, Roark; Anderson, Scott; Barty, Christopher; Chu, Tak Sum; Ebbers, Chris; Gibson, David et al.
Object Type: Article
System: The UNT Digital Library
Advances in NIF Shock Timing Experiments (open access)

Advances in NIF Shock Timing Experiments

None
Date: July 10, 2012
Creator: Robey, H. F.; Celliers, P. M.; Moody, J. D. & MacKinnon, A. J.
Object Type: Article
System: The UNT Digital Library
Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime (open access)

Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime

A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.
Date: July 5, 2012
Creator: Higo, Toshiyasu; Higashi, Yasuo; Matsumoto, Shuji; Yokoyama, Kazue; Adolphsen, Chris; Dolgashev, Valery et al.
Object Type: Article
System: The UNT Digital Library
Advancing Residential Retrofits in Atlanta (open access)

Advancing Residential Retrofits in Atlanta

This report will summarize the home energy improvements performed in the Atlanta, GA area. In total, nine homes were retrofitted with eight of the homes having predicted source energy savings of approximately 30% or greater based on simulated energy consumption.
Date: July 1, 2012
Creator: Jackson, Roderick K; Kim, Eyu-Jin; Roberts, Sydney & Stephenson, Robert
Object Type: Report
System: The UNT Digital Library
Aerial Radiation Measurements from the Fukushima Dai-ichi Nuclear Power Plant Accident (open access)

Aerial Radiation Measurements from the Fukushima Dai-ichi Nuclear Power Plant Accident

This document is a slide show type presentation concerning DOE and Aerial Measuring System (AMS) activities and results with respect to assessing the consequences of the releases from the Fukushima Dai-ichi Nuclear Power Plant. These include ground monitoring and aerial monitoring.
Date: July 16, 2012
Creator: Guss, P. P.
Object Type: Article
System: The UNT Digital Library
Aerosol Best Estimate Value-Added Product (open access)

Aerosol Best Estimate Value-Added Product

The objective of the Aerosol Best Estimate (AEROSOLBE) value-added product (VAP) is to provide vertical profiles of aerosol extinction, single scatter albedo, asymmetry parameter, and Angstroem exponents for the atmospheric column above the Central Facility at the ARM Southern Great Plains (SGP) site. We expect that AEROSOLBE will provide nearly continuous estimates of aerosol optical properties under a range of conditions (clear, broken clouds, overcast clouds, etc.). The primary requirement of this VAP was to provide an aerosol data set as continuous as possible in both time and height for the Broadband Heating Rate Profile (BBHRP) VAP in order to provide a structure for the comprehensive assessment of our ability to model atmospheric radiative transfer for all conditions. Even though BBHRP has been completed, AEROSOLBE results are very valuable for environmental, atmospheric, and climate research.
Date: July 19, 2012
Creator: Flynn, C; Turner, D; Koontz, A; Chand, D & Sivaraman, C
Object Type: Report
System: The UNT Digital Library
AGC-2 Irradiation Data Qualification Final Report (open access)

AGC-2 Irradiation Data Qualification Final Report

The Graphite Technology Development Program will run a series of six experiments to quantify the effects of irradiation on nuclear grade graphite. The second Advanced Graphite Creep (AGC) experiment (AGC-2) began with Advanced Test Reactor (ATR) Cycle 149A on April 12, 2011, and ended with ATR Cycle 151B on May 5, 2012. The purpose of this report is to qualify AGC-2 irradiation monitoring data following INL Management and Control Procedure 2691, Data Qualification. Data that are Qualified meet the requirements for data collection and use as described in the experiment planning and quality assurance documents. Data that do not meet the requirements are Failed. Some data may not quite meet the requirements, but may still provide some useable information. These data are labeled as Trend. No Trend data were identified for the AGC-2 experiment. All thermocouples functioned throughout the AGC-2 experiment. There was one instance where spurious signals or instrument power interruption resulted in a recorded temperature value being well outside physical reality. This value was identified and labeled as Failed data. All other temperature data are Qualified. All helium and argon gas flow data are within expected ranges. Total gas flow was approximately 50 sccm through the capsule. Helium …
Date: July 1, 2012
Creator: Hull, Laurence C.
Object Type: Report
System: The UNT Digital Library
Ahorro Energia: Consejos Sobre Como Ahorrar Dinero y Energia en su Casa [Brochure] (open access)

Ahorro Energia: Consejos Sobre Como Ahorrar Dinero y Energia en su Casa [Brochure]

The Spanish-language version of U.S. Department of Energy's consumer guide to saving energy and money at home and on the road.
Date: July 1, 2012
Creator: unknown
Object Type: Pamphlet
System: The UNT Digital Library
AHTR Refueling Systems and Process Description (open access)

AHTR Refueling Systems and Process Description

The Advanced High-Temperature Reactor (AHTR) is a design concept for a central station-type [1500 MW(e)] Fluoride salt–cooled High-temperature Reactor (FHR) that is currently undergoing development by Oak Ridge National Laboratory for the US. Department of Energy, Office of Nuclear Energy’s Advanced Reactor Concepts program. FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The overall goal of the AHTR development program is to demonstrate the technical feasibility of FHRs as low-cost, large-size power producers while maintaining full passive safety. The AHTR is approaching a preconceptual level of maturity. An initial integrated layout of its major systems, structures, and components (SSCs), and an initial, high-level sequence of operations necessary for constructing and operating the plant is nearing completion. An overview of the current status of the AHTR concept has been recently published [1], and a report providing a more detailed overview of the AHTR structures and mechanical systems is currently in preparation. This report documents the refueling components and processes envisioned at this early development phase. The report is limited to the refueling aspects of the AHTR and does not include overall reactor or power plant design information. The …
Date: July 15, 2012
Creator: Varma, V. K.; Holcomb, D. E.; Bradley, E. C.; Zaharia, N. M. & Cooper, E. J.
Object Type: Report
System: The UNT Digital Library