Final Progress Report for THERMOPHYSICAL PROPERTIES OF FLUIDS AND FLUID MIXTURES (open access)

Final Progress Report for THERMOPHYSICAL PROPERTIES OF FLUIDS AND FLUID MIXTURES

The DOE supported research is a theoretical statistical-mechanical based study of the thermophysical properties of fluids and fluid mixtures. It focuses upon thermodynamic and transport properties in particular. In addition the study covers the development of new ways for predicting the microscopic structure of fluids in a wide range of thermodynamic state parameters, including the critical point.
Date: January 28, 2009
Creator: Stell, George
Object Type: Report
System: The UNT Digital Library
The Coming Nuclear Renaissance for Next Generation Safeguards Specialists--Maximizing Potential and Minimizing the Risks (open access)

The Coming Nuclear Renaissance for Next Generation Safeguards Specialists--Maximizing Potential and Minimizing the Risks

This document is intended to provide an overview of the workshop entitled 'The Coming Nuclear Renaissance for the Next Generation Safeguards Experts-Maximizing Benefits While Minimizing Proliferation Risks', conducted at Oak Ridge National Laboratory (ORNL) in partnership with the Y-12 National Security Complex (Y-12) and the Savannah River National Laboratory (SRNL). This document presents workshop objectives; lists the numerous participant universities and individuals, the nuclear nonproliferation lecture topics covered, and the facilities tours taken as part of the workshop; and discusses the university partnership sessions and proposed areas for collaboration between the universities and ORNL for 2009. Appendix A contains the agenda for the workshop; Appendix B lists the workshop attendees and presenters with contact information; Appendix C contains graphics of the evaluation form results and survey areas; and Appendix D summarizes the responses to the workshop evaluation form. The workshop was an opportunity for ORNL, Y-12, and SRNL staff with more than 30 years combined experience in nuclear nonproliferation to provide a comprehensive overview of their expertise for the university professors and their students. The overall goal of the workshop was to emphasize nonproliferation aspects of the nuclear fuel cycle and to identify specific areas where the universities and experts …
Date: January 1, 2009
Creator: Eipeldauer, Mary D
Object Type: Report
System: The UNT Digital Library
Life Cost Based FMEA Manual: A Step by Step Guide to Carrying Out a Cost-based Failure Modes and Effects Analysis (open access)

Life Cost Based FMEA Manual: A Step by Step Guide to Carrying Out a Cost-based Failure Modes and Effects Analysis

Failure occurs when one or more of the intended functions of a product are no longer fulfilled to the customer's satisfaction. The most critical product failures are those that escape design reviews and in-house quality inspection and are found by the customer. The product may work for a while until its performance degrades to an unacceptable level or it may have not worked even before customer took possession of the product. The end results of failures which may lead to unsafe conditions or major losses of the main function are rated high in severity. Failure Modes and Effects Analysis (FMEA) is a tool widely used in the automotive, aerospace, and electronics industries to identify, prioritize, and eliminate known potential failures, problems, and errors from systems under design, before the product is released (Stamatis, 1997). Several industrial FMEA standards such as those published by the Society of Automotive Engineers, US Department of Defense, and the Automotive Industry Action Group employ the Risk Priority Number (RPN) to measure risk and severity of failures. The Risk Priority Number (RPN) is a product of 3 indices: Occurrence (O), Severity (S), and Detection (D). In a traditional FMEA process design engineers typically analyze the 'root …
Date: January 23, 2009
Creator: Rhee, Seung; Spencer, Cherrill & /SLAC, /Stanford U.
Object Type: Report
System: The UNT Digital Library
Characterizing the Properties of Clusters of Galaxies As a Function of Luminosity and Redshift (open access)

Characterizing the Properties of Clusters of Galaxies As a Function of Luminosity and Redshift

Abstract: We report the application of the new Monte Carlo method, Smoothed Particle Inference (SPI, described in a pair of companion papers), towards analysis and interpretation of X-ray observations of clusters of galaxies with the XMM-Newton satellite. Our sample consists of publicly available well-exposed observations of clusters at redshifts z > 0.069, totaling 101 objects. We determine the luminosity and temperature structure of the X-ray emitting gas, with the goal to quantify the scatter and the evolution of the L{sub X} - T relation, as well as to investigate the dependence on cluster substructure with redshift. This work is important for the establishment of the potential robustness of mass estimates from X-ray data which in turn is essential towards the use of clusters for measurements of cosmological parameters. We use the luminosity and temperature maps derived via the SPI technique to determine the presence of cooling cores, via measurements of luminosity and temperature contrast. The L{sub X}-T relation is investigated, and we confirm that L{sub X} {proportional_to} T{sup 3}. We find a weak redshift dependence ({proportional_to} (1 + z){sup {beta}{sub LT}}, {beta}{sub LT} = 0.50 {+-} 0.34), in contrast to some Chandra results. The level of dynamical activity is established …
Date: February 24, 2009
Creator: Andersson, K.; Peterson, J. R.; Madejski, G. & Goobar, A.
Object Type: Article
System: The UNT Digital Library
Improved Biorefinery for the Production of Ethanol, Chemicals, Animal Feed and Biomaterials From Sugar Cane (open access)

Improved Biorefinery for the Production of Ethanol, Chemicals, Animal Feed and Biomaterials From Sugar Cane

The Audubon Sugar Institute (ASI) of Louisiana State University’s Agricultural Center (LSU AgCenter) and MBI International (MBI) sought to develop technologies that will lead to the development of a sugar-cane biorefinery, capable of supplying fuel ethanol from bagasse. Technology development focused on the conversion of bagasse, cane-leaf matter (CLM) and molasses into high value-added products that included ethanol, specialty chemicals, biomaterials and animal feed; i.e. a sugar cane-based biorefinery. The key to lignocellulosic biomass utilization is an economically feasible method (pretreatment) for separating the cellulose and the hemicellulose from the physical protection provided by lignin. An effective pretreatment disrupts physical barriers, cellulose crystallinity, and the association of lignin and hemicellulose with cellulose so that hydrolytic enzymes can access the biomass macrostructure (Teymouri et al. 2004, Laureano-Perez, 2005). We chose to focus on alkaline pretreatment methods for, and in particular, the Ammonia Fiber Expansion (AFEX) process owned by MBI. During the first two years of this program a laboratory process was established for the pretreatment of bagasse and CLM using the AFEX process. There was significant improvement of both rate and yield of glucose and xylose upon enzymatic hydrolysis of AFEX-treated bagasse and CLM compared with untreated material. Because of reactor …
Date: January 29, 2009
Creator: Day, Donal F.
Object Type: Report
System: The UNT Digital Library
Search for associated production of charginos and neutralinos in the trilepton final state using 2.3 fb**-1 of data (open access)

Search for associated production of charginos and neutralinos in the trilepton final state using 2.3 fb**-1 of data

We report the results of a search for associated production of charginos and neutralinos using a data set corresponding to an integrated luminosity of 2.3 fb{sup -1} collected with the D0 experiment during Run II of the Tevatron proton-antiproton collider. Final states containing three charged leptons and missing transverse energy are probed for a signal from supersymmetry with four dedicated trilepton event selections. No evidence for a signal is observed, and we set limits on the product of production cross section and leptonic branching fraction. Within minimal supergravity, these limits translate into bounds on m{sub 0} and m{sub 1/2} that are well beyond existing limits.
Date: January 1, 2009
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Phase I Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nevada Test Site, Nye County, Nevada with Errata Sheet 1, 2, 3, Revision 1 (open access)

Phase I Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nevada Test Site, Nye County, Nevada with Errata Sheet 1, 2, 3, Revision 1

As prescribed in the Pahute Mesa Corrective Action Investigation Plan (CAIP) (DOE/NV, 1999) and Appendix VI of the Federal Facility Agreement and Consent Order (FFACO) (1996, as amended February 2008), the ultimate goal of transport analysis is to develop stochastic predictions of a contaminant boundary at a specified level of uncertainty. However, because of the significant uncertainty of the model results, the primary goal of this report was modified through mutual agreement between the DOE and the State of Nevada to assess the primary model components that contribute to this uncertainty and to postpone defining the contaminant boundary until additional model refinement is completed. Therefore, the role of this analysis has been to understand the behavior of radionuclide migration in the Pahute Mesa (PM) Corrective Action Unit (CAU) model and to define, both qualitatively and quantitatively, the sensitivity of such behavior to (flow) model conceptualization and (flow and transport) parameterization.
Date: February 1, 2009
Creator: Ruskauff, Greg
Object Type: Report
System: The UNT Digital Library
Molecular dissection of the roles of the SOD genes in mammalian response to low dose irradiation (open access)

Molecular dissection of the roles of the SOD genes in mammalian response to low dose irradiation

“Molecular dissection of the roles of the SOD genes in mammalian response to low dose irradiation " was started on 09/01/03 and ended on 08/31/07. The primary objective of the project was to carry out mechanistic studies of the roles of the anti-oxidant SOD genes in mammalian cellular response to low dose ionizing radiation.
Date: January 27, 2009
Creator: Li, Dr. Chuan-Yaun
Object Type: Text
System: The UNT Digital Library
EMSL Fiscal Year 2008 Annual Report (open access)

EMSL Fiscal Year 2008 Annual Report

This annual report provides details on the research conducted at EMSL--the Environmental Molecular Sciences Laboratory in Fiscal Year 2008.
Date: January 23, 2009
Creator: Showalter, Mary Ann
Object Type: Report
System: The UNT Digital Library
Identification of Strategies to Leverage Public and Private Resources for National Security Workforce Development (open access)

Identification of Strategies to Leverage Public and Private Resources for National Security Workforce Development

This report documents the identification of strategies to leverage public and private resources for the development of an adequate national security workforce as part of the National Security Preparedness Project (NSPP).There are numerous efforts across the United States to develop a properly skilled and trained national security workforce. Some of these efforts are the result of the leveraging of public and private dollars. As budget dollars decrease and the demand for a properly skilled and trained national security workforce increases, it will become even more important to leverage every education and training dollar. The leveraging of dollars serves many purposes. These include increasing the amount of training that can be delivered and therefore increasing the number of people reached, increasing the number and quality of public/private partnerships, and increasing the number of businesses that are involved in the training of their future workforce.
Date: February 1, 2009
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Determination of Ideal Broth Formulations Needed to Prepare Hydrous Aluminum Oxide Microspheres via the Internal Gelation Process (open access)

Determination of Ideal Broth Formulations Needed to Prepare Hydrous Aluminum Oxide Microspheres via the Internal Gelation Process

A simple test-tube methodology was used to determine optimum process parameters for preparing hydrous aluminum oxide microspheres by the internal gelation process. Broth formulations of aluminum, hexamethylenetetramine, and urea were found that can be used to prepare hydrous aluminum oxide gel spheres in the temperature range of 60-90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations in order to equate the test-tube gelation times with actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broths.
Date: February 1, 2009
Creator: Collins, Jack Lee & Pye, S. L.
Object Type: Report
System: The UNT Digital Library
CEMENTITIOUS BARRIERS MODELING FOR PERFORMANCE ASSESSMENTS OF SHALLOW LAND BURIAL OF LOW LEVEL RADIOACTIVE WASTE - 9243 (open access)

CEMENTITIOUS BARRIERS MODELING FOR PERFORMANCE ASSESSMENTS OF SHALLOW LAND BURIAL OF LOW LEVEL RADIOACTIVE WASTE - 9243

The Cementitious Barriers Partnership (CBP) was created to develop predictive capabilities for the aging of cementitious barriers over long timeframes. The CBP is a multi-agency, multi-national consortium working under a U.S. Department of Energy (DOE) Environmental Management (EM-21) funded Cooperative Research and Development Agreement (CRADA) with the Savannah River National Laboratory (SRNL) as the lead laboratory. Members of the CBP are SRNL, Vanderbilt University, the U.S. Nuclear Regulatory Commission (USNRC), National Institute of Standards and Technology (NIST), SIMCO Technologies, Inc. (Canada), and the Energy Research Centre of the Netherlands (ECN). A first step in developing advanced tools is to determine the current state-of-the-art. A review has been undertaken to assess the treatment of cementitious barriers in Performance Assessments (PA). Representatives of US DOE sites which have PAs for their low level waste disposal facilities were contacted. These sites are the Idaho National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory, Nevada Test Site, and Hanford. Several of the more arid sites did not employ cementitious barriers. Of those sites which do employ cementitious barriers, a wide range of treatment of the barriers in a PA was present. Some sites used conservative, simplistic models that even though conservative still showed …
Date: January 9, 2009
Creator: Taylor, G
Object Type: Article
System: The UNT Digital Library
Environmental Biosciences Program Quarterly Report (open access)

Environmental Biosciences Program Quarterly Report

Current research projects have focused Environmental Biosciences Program (EBP) talent and resources on providing the scientific basis for risk-based standards, risk-based decision making and the accelerated clean-up of widespread environmental hazards. These hazards include trichloroethylene, low-dose ionizing radiation (gamma and neutron) and alpha radiation from plutonium. Trichloroethylene research has been conducted as a joint collaborative effort with the University of Georgia. Work on the trichloroethylene research projects has been slowed as a result of funding uncertainties. The impact of these funding uncertainties has been discussed with the United States Department of Energy (DOE). Laboratory work has been completed on several trichloroethylene risk assessment projects, and these projects have been brought to a close. Plans for restructuring the performance schedule of the remaining trichloroethylene projects have been submitted to the department. A comprehensive manuscript on the scientific basis of trichloroethylene risk assessment is in preparation. Work on the low-dose radiation risk assessment projects is also progressing at a slowed rate as a result of funding uncertainties. It has been necessary to restructure the proponency and performance schedule of these projects, with the project on Low-Dose Radiation: Epidemiology Risk Models transferred to DOE Office of Science proponency under a separate funding instrument. …
Date: January 30, 2009
Creator: Mohr, Lawrence C.
Object Type: Report
System: The UNT Digital Library
Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code (open access)

Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code

A beam excited 56 MHz Radio Frequency (RF) Niobium Quarter Wave Resonator (QWR) has been proposed to enhance RHIC beam luminosity and bunching. Being a RF cavity, multipacting is expected; therefore an extensive study was carried out with the Multipac 2.1 2D simulation code. The study revealed that multipacting occurs in various bands up to peak surface electric field 50 kV/m and is concentrated mostly above the beam gap and on the outer conductor. To suppress multipacting, a ripple structure was introduced to the outer conductor and the phenomenon was successfully eliminated from the cavity.
Date: January 2, 2009
Creator: Naik, D. & Ben-Zvi, Ilan
Object Type: Report
System: The UNT Digital Library
Results from the B Factories (open access)

Results from the B Factories

These proceedings are based on lectures given at the Helmholtz International Summer School Heavy Quark Physics at the Bogoliubov Laboratory of Theoretical Physics, Dubna, Russia, during August 2008. I review the current status of CP violation in B meson decays from the B factories. These results can be used, along with measurements of the sides of the Unitarity Triangle, to test the CKM mechanism. In addition I discuss experimental studies of B decays to final states with 'spin-one' particles.
Date: January 8, 2009
Creator: Bevan, A. & /Queen Mary, U. of London
Object Type: Article
System: The UNT Digital Library
Composite Analysis of Llw Disposal Facilities at the U. S. Department of Energy's Savannah River Site (open access)

Composite Analysis of Llw Disposal Facilities at the U. S. Department of Energy's Savannah River Site

Composite Analyses (CA's) are required per DOE Order 435.1 [1], in order to provide a reasonable expectation that DOE low-level waste (LLW) disposal, high-level waste tank closure, and transuranic (TRU) waste disposal in combination with Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Resource Conservation and Recovery Act (RCRA), and deactivation and decommissioning (D&D) actions, will not result in the need for future remedial actions in order to ensure radiological protection of the public and environment. This Order requires that an accounting of all sources of DOE man-made radionuclides and DOE enhanced natural radionuclides that are projected to remain on the site after all DOE site operations have ceased. This CA updates the previous CA that was developed in 1997. As part of this CA, an inventory of expected radionuclide residuals was conducted, exposure pathways were screened and a model was developed such that a dose to the MOP at the selected points of exposure might be evaluated.
Date: January 8, 2009
Creator: Hiergesell, R. A.; Phifer, M. A. & Smith, F. G.
Object Type: Article
System: The UNT Digital Library
Noise in a Calorimeter Readout System Using Periodic Sampling (open access)

Noise in a Calorimeter Readout System Using Periodic Sampling

Fourier transform analysis of the calorimeter noise problem gives quantitative results on (a) the time-height correlation, (b) the effect of background on optimal shaping and on the ENC, (c) sampling frequency requirements, and (d) the relation between sampling frequency and the required quantization error.
Date: February 26, 2009
Creator: Innes, Walter R.
Object Type: Report
System: The UNT Digital Library
SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008 (open access)

SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008

None
Date: February 10, 2009
Creator: AK, LEE
Object Type: Report
System: The UNT Digital Library
Two-photon double ionization of H2 at 30 eV using Exterior Complex Scaling (open access)

Two-photon double ionization of H2 at 30 eV using Exterior Complex Scaling

Calculations of fully differential cross sections for two-photon double ionization of the hydrogen molecule with photons of 30 eV are reported. The results have been obtained by using the method of exterior complex scaling, which allows one to construct essentially exact wave functions that describe thedouble continuum on a large, but finite, volume. The calculated cross sections are compared with those previously obtained by Colgan et al., and discrepancies are found for specific molecular orientations and electron ejection directions.
Date: January 20, 2009
Creator: Morales, Felipe; Martin, Fernando; Horner, Daniel; Rescigno, Thomas N. & McCurdy, C. William
Object Type: Article
System: The UNT Digital Library
Effects of Energy Chirp on Echo-Enabled Harmonic Generation Free-Electron Lasers (open access)

Effects of Energy Chirp on Echo-Enabled Harmonic Generation Free-Electron Lasers

We study effects of energy chirp on echo-enabled harmonic generation (EEHG). Analytical expressions are compared with numerical simulations for both harmonic and bunching factors. We also discuss the EEHG free-electron laser bandwidth increase due to an energy-modulated beam and its pulse length dependence on the electron energy chirp.
Date: February 23, 2009
Creator: Huang, Z.; Ratner, D.; Stupakov, G. & Xiang, D.
Object Type: Report
System: The UNT Digital Library
Planar LTCC transformers for high voltage flyback converters: Part II. (open access)

Planar LTCC transformers for high voltage flyback converters: Part II.

This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.
Date: February 1, 2009
Creator: Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD) & Abel, David (NASCENTechnology, Inc., Watertown, SD)
Object Type: Report
System: The UNT Digital Library
REMOVING SLUDGE HEELS FROM SAVANNAH RIVER SITE WASTE TANKS BY OXALIC ACID DISSOLUTION (open access)

REMOVING SLUDGE HEELS FROM SAVANNAH RIVER SITE WASTE TANKS BY OXALIC ACID DISSOLUTION

The Savannah River Site (SRS) will remove sludge as part of waste tank closure operations. Typically the bulk sludge is removed by mixing it with supernate to produce a slurry, and transporting the slurry to a downstream tank for processing. Experience shows that a residual heel may remain in the tank that cannot be removed by this conventional technique. In the past, SRS used oxalic acid solutions to disperse or dissolve the sludge heel to complete the waste removal. To better understand the actual conditions of oxalic acid cleaning of waste from carbon steel tanks, the authors developed and conducted an experimental program to determine its effectiveness in dissolving sludge, the hydrogen generation rate, the generation rate of other gases, the carbon steel corrosion rate, the impact of mixing on chemical cleaning, the impact of temperature, and the types of precipitates formed during the neutralization process. The test samples included actual SRS sludge and simulated SRS sludge. The authors performed the simulated waste tests at 25, 50, and 75 C by adding 8 wt % oxalic acid to the sludge over seven days. They conducted the actual waste tests at 50 and 75 C by adding 8 wt % oxalic …
Date: March 1, 2009
Creator: Poirier, M; David Herman, D; Fernando Fondeur, F; John Pareizs, J; Michael Hay, M; Bruce Wiersma, B et al.
Object Type: Article
System: The UNT Digital Library
Tau Decays at BaBar (open access)

Tau Decays at BaBar

Recent results of tau lepton decay studies based on luminosities between 350 fb{sup -1} and 469 fb{sup -1} collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory are presented. The analyses reported here are Charged Current Lepton Universality and measurements of |V{sub us}| using {tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}, {mu}{sup -}{bar {nu}}{sub {mu}}{nu}{sub {tau}}, {pi}{sup -} {nu}{sub {tau}}, and K{sup -}{nu}{sub {tau}} decays, as well as searches for Second Class Currents in {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decays, studies of Lepton Flavor Violations, and a tau mass measurement and CPT-Test. If not explicitly mentioned, charge conjugate decay modes are also implied. decays, as well as searches for Second Class Currents in {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decays, studies of Lepton Flavor Violations, and a tau mass measurement and CPT-Test. If not explicitly mentioned, charge conjugate decay modes are also implied.
Date: January 22, 2009
Creator: Hast, Carsten
Object Type: Article
System: The UNT Digital Library
DEMOLISHING A COLD WARE ERA FULE STORAGE BASIN SUPERSTRUCTURE LADEN WITH ASBESTOS (open access)

DEMOLISHING A COLD WARE ERA FULE STORAGE BASIN SUPERSTRUCTURE LADEN WITH ASBESTOS

The K East (KE) Basin facilities are located near the north end of the Hanford Site's 100 K area. The facilities were built in 1950 as part of the KE Reactor complex and constructed within 400 meters of the Columbia River, which is the largest river in the Pacific Northwest and by volume the fourth largest river in the United States. The basin, located adjacent to the reactor, was used for the underwater storage of irradiated nuclear fuel discharged from the reactor. The basin was covered by a superstructure comprising steel columns and beams, concrete, and cement asbestos board (CAB) siding. The project's mission was to complete demolition of the structure over the KE Basin within six months of turnover from facility deactivation activities. The demolition project team applied open-air demolition techniques to bring the facility to slab-on-grade. Several innovative techniques were used to control contamination and maintain contamination control within the confines of the demolition exclusion zone. The techniques, which focused on a defense-in-depth approach, included spraying fixatives on interior and exterior surfaces before demolition began; applying fixatives during the demolition; misting using a fine spray of water during demolition; and demolishing the facility systematically. Another innovative approach that …
Date: January 12, 2009
Creator: ER, LLOYD; JM, STEVENS; EB, DAGAN; TK, ORGILL; MA, GREEN; CH, LARSON et al.
Object Type: Article
System: The UNT Digital Library