States

Actinides and Rare Earths Topical Conference (Code AC) (open access)

Actinides and Rare Earths Topical Conference (Code AC)

Actinide and the Rare Earth materials exhibit many unique and diverse physical, chemical and magnetic properties, in large part because of the complexity of their f electronic structure. This Topical Conference will focus upon the chemistry, physics and materials science in Lanthanide and Actinide materials, driven by 4f and 5f electronic structure. Particular emphasis will be placed upon 4f/5f magnetic structure, surface science and thin film properties. For the actinides, fundamental actinide science and its role in resolving technical challenges posed by actinide materials will be stressed. Both basic and applied experimental approaches, including synchrotron-radiation-based investigations, as well as theoretical modeling and computational simulations, are planned to be part of the Topical Conference. Of particular importance are the issues related to the potential renaissance in Nuclear Fuels, including synthesis, oxidation, corrosion, intermixing, stability in extreme environments, prediction of properties via benchmarked simulations, separation science, environmental impact and disposal of waste products.
Date: November 24, 2009
Creator: Tobin, J G
Object Type: Article
System: The UNT Digital Library
First Direct Observation of a Nearly Ideal Graphene Band Structure (open access)

First Direct Observation of a Nearly Ideal Graphene Band Structure

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Date: November 24, 2009
Creator: Sprinkle, M; Siegel, D; Hu, Y; Hicks, J; Tejeda, A; Taleb-Ibrahimi, A et al.
Object Type: Article
System: The UNT Digital Library
First Step Towards a Non-Adiabatic Description of the Fission Process Based on the Generator Coordinate Method (open access)

First Step Towards a Non-Adiabatic Description of the Fission Process Based on the Generator Coordinate Method

Among the different theoretical approaches able to describe fission, microscopic ones can help us in the understanding of this process, as they have the advantage of describing the nuclear structure and the dynamics in a consistent manner. The sole input of the calculations is the nucleon-nucleon interaction. Such a microscopic time-dependent and quantum mechanical formalism has already been used, based on the Gaussian Overlap Approximation of the Generator Coordinate Method with the adiabatic approximation, to analyze the collective dynamics of low-energy fission in {sup 238}U. However, at higher energies, a few MeV above the barrier, the adiabatic approximation doesn't seem valid anymore. Indeed, manifestations of proton pair breaking have been observed in {sup 238}U and {sup 239}U for an excitation energy of 2.3 MeV above the barrier. Taking the intrinsic excitations into account during the fission process will enable us to determine the coupling between collective and intrinsic degrees of freedom, in particular from saddle to scission. Guidelines of the new formalism under development are presented and some preliminary results on overlaps between non excited and excited states are discussed.
Date: November 24, 2009
Creator: Bernard, R; Goutte, H; Gogny, D; Dubray, N & Lacroix, D
Object Type: Article
System: The UNT Digital Library
High Level Trigger Configuration and Handling of Trigger Tables in the CMS Filter Farm (open access)

High Level Trigger Configuration and Handling of Trigger Tables in the CMS Filter Farm

The CMS experiment at the CERN Large Hadron Collider is currently being commissioned and is scheduled to collect the first pp collision data in 2008. CMS features a two-level trigger system. The Level-1 trigger, based on custom hardware, is designed to reduce the collision rate of 40 MHz to approximately 100 kHz. Data for events accepted by the Level-1 trigger are read out and assembled by an Event Builder. The High Level Trigger (HLT) employs a set of sophisticated software algorithms, to analyze the complete event information, and further reduce the accepted event rate for permanent storage and analysis. This paper describes the design and implementation of the HLT Configuration Management system. First experiences with commissioning of the HLT system are also reported.
Date: November 24, 2009
Creator: Bauer, G.; Behrens, U.; Boyer, V.; Branson, J.; Brett, A.; Cano, E. et al.
Object Type: Article
System: The UNT Digital Library
Lake Whitney Comprehensive Water Quality Assessment, Phase 1B- Physical and Biological Assessment (USDOE) (open access)

Lake Whitney Comprehensive Water Quality Assessment, Phase 1B- Physical and Biological Assessment (USDOE)

Baylor University Center for Reservoir and Aquatic Systems Research (CRASR) has conducted a phased, comprehensive evaluation of Lake Whitney to determine its suitability for use as a regional water supply reservoir. The area along the Interstate 35 corridor between Dallas / Fort Worth Metroplex and the Waco / Temple Centroplex represents one of the fastest growth areas in the State of Texas and reliable water supplies are critical to sustainable growth. Lake Whitney is situated midway between these two metropolitan areas. Currently, the City of Whitney as well as all of Bosque and Hill counties obtain their potable water from the Trinity Sands aquifer. Additionally, parts of the adjoining McLennan and Burleson counties utilize the Trinity sands aquifer system as a supplement to their surface water supplies. Population growth coupled with increasing demands on this aquifer system in both the Metroplex and Centroplex have resulted in a rapid depletion of groundwater in these rural areas. The Lake Whitney reservoir represents both a potentially local and regional solution for an area experiencing high levels of growth. Because of the large scope of this project as well as the local, regional and national implications, we have designed a multifaceted approach that will …
Date: November 24, 2009
Creator: Doyle, Robert D & Byars, Bruce W
Object Type: Report
System: The UNT Digital Library
LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS (open access)

LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS

The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of each containment vessel is credited for leaktight containment per ANSI N14.5. O-ring service life depends on many factors, including the failure criterion, environmental conditions, overall design, fabrication quality and assembly practices. A preliminary life prediction model has been developed for the V0835-75 O-rings in KAMS. The conservative model is based primarily on long-term compression stress relaxation (CSR) experiments and Arrhenius accelerated-aging methodology. For model development purposes, seal lifetime is defined as a 90% loss of measurable sealing force. Thus far, CSR experiments have only reached this target level of degradation at temperatures {ge} 300 F. At lower temperatures, relaxation values are more tolerable. Using time-temperature superposition principles, the conservative model predicts a service life of approximately 20-25 years at a constant seal temperature of 175 F. This represents a maximum payload package at a constant ambient temperature of 104 F, …
Date: November 24, 2009
Creator: Hoffman, E. & Skidmore, E.
Object Type: Report
System: The UNT Digital Library
A New Class of Non-Linear, Finite-Volume Methods for Vlasov Simulation (open access)

A New Class of Non-Linear, Finite-Volume Methods for Vlasov Simulation

Methods for the numerical discretization of the Vlasov equation should efficiently use the phase space discretization and should introduce only enough numerical dissipation to promote stability and control oscillations. A new high-order, non-linear, finite-volume algorithm for the Vlasov equation that discretely conserves particle number and controls oscillations is presented. The method is fourth-order in space and time in well-resolved regions, but smoothly reduces to a third-order upwind scheme as features become poorly resolved. The new scheme is applied to several standard problems for the Vlasov-Poisson system, and the results are compared with those from other finite-volume approaches, including an artificial viscosity scheme and the Piecewise Parabolic Method. It is shown that the new scheme is able to control oscillations while preserving a higher degree of fidelity of the solution than the other approaches.
Date: November 24, 2009
Creator: Banks, J W & Hittinger, J A
Object Type: Article
System: The UNT Digital Library
On the Performance of an Algebraic Multigrid Solver on Multicore Clusters (open access)

On the Performance of an Algebraic Multigrid Solver on Multicore Clusters

Algebraic multigrid (AMG) solvers have proven to be extremely efficient on distributed-memory architectures. However, when executed on modern multicore cluster architectures, we face new challenges that can significantly harm AMG's performance. We discuss our experiences on such an architecture and present a set of techniques that help users to overcome the associated problems, including thread and process pinning and correct memory associations. We have implemented most of the techniques in a MultiCore SUPport library (MCSup), which helps to map OpenMP applications to multicore machines. We present results using both an MPI-only and a hybrid MPI/OpenMP model.
Date: November 24, 2009
Creator: Baker, A.; Schulz, M. & Yang, U. M.
Object Type: Article
System: The UNT Digital Library
PROPERTIES AND BEHAVIOR OF 238PU RELEVANT TO DECONTAMINATION OF BUILDING 235-F (open access)

PROPERTIES AND BEHAVIOR OF 238PU RELEVANT TO DECONTAMINATION OF BUILDING 235-F

This report was prepared to document the physical, chemical and radiological properties of plutonium oxide materials that were processed in the Plutonium Fuel Form Facility (PuFF) in building 235-F at the Savannah River Plant (now known as the Savannah River Site) in the late 1970s and early 1980s. An understanding of these properties is needed to support current project planning for the safe and effective decontamination and deactivation (D&D) of PuFF. The PuFF mission was production of heat sources to power Radioisotope Thermoelectric Generators (RTGs) used in space craft. The specification for the PuO{sub 2} used to fabricate the heat sources required that the isotopic content of the plutonium be 83 {+-} 1% Pu-238 due to its high decay heat of 0.57 W/g. The high specific activity of Pu-238 (17.1 Ci/g) due to alpha decay makes this material very difficult to manage. The production process produced micron-sized particles which proved difficult to contain during operations, creating personnel contamination concerns and resulting in the expenditure of significant resources to decontaminate spaces after loss of material containment. This report examines high {sup 238}Pu-content material properties relevant to the D&D of PuFF. These relevant properties are those that contribute to the mobility of …
Date: November 24, 2009
Creator: Duncan, A. & Kane, M.
Object Type: Report
System: The UNT Digital Library
Analysis of the Reactivity of Radpro Solution With Cotton Rags (open access)

Analysis of the Reactivity of Radpro Solution With Cotton Rags

This report addresses the analysis of the reactivity of RadPro solution with cotton rags.
Date: September 24, 2009
Creator: Marusich, R. M.
Object Type: Report
System: The UNT Digital Library
A Decade of NSTX Operations Using Collaborative Software (open access)

A Decade of NSTX Operations Using Collaborative Software

Since the beginning of the National Spherical Torus Experiment's (NSTX) research activities in 1999, open-source and collaborative software have been used extensively for experimental operations. The software included Experimental Physics and Industrial Control System (EPICS) and the Model Data System plus (MDSplus). This paper will begin with a retrospective of ten years of integrated computing, control, and data analysis on NSTX. A variety of practical issues will be reviewed such as: system reliability, availability, and maintainability; using open source software with commercialoff- the-shelf (COTS) hardware; obsolescence and remaining current. Recent improvements, current status, and emerging issues will be presented. Numerous proposals for NSTX upgrades have been made that will extend the performance and operating lifetime of NSTX. In light of this, a collective strategy for improving NSTX's collaborative software model for a new decade of operations will be examined.
Date: September 24, 2009
Creator: P. Sichta, W. Davis, J. Dong, D. Mastrovito, G. Tchilinguirian, G. Zimmer
Object Type: Article
System: The UNT Digital Library
Hanford Internal Dosimetry Program Manual, PNL-MA-552 (open access)

Hanford Internal Dosimetry Program Manual, PNL-MA-552

This manual is a guide to the services provided by the Hanford Internal Dosimetry Program (IDP), which is operated by the Pacific Northwest National Laboratory.( ) for the U.S. Department of Energy Richland Operations Office, Office of River Protection and their Hanford Site contractors. The manual describes the roles of and relationships between the IDP and the radiation protection programs of the Hanford Site contractors. Recommendations and guidance are also provided for consideration in implementing bioassay monitoring and internal dosimetry elements of radiation protection programs.
Date: September 24, 2009
Creator: Carbaugh, Eugene H.; Bihl, Donald E. & Maclellan, Jay A.
Object Type: Report
System: The UNT Digital Library
The KTOI Ecosystem Project Relational Database : a Report Prepared by Statistical Consulting Services for KTOI Describing the Key Components and Specifications of the KTOI Relational Database. (open access)

The KTOI Ecosystem Project Relational Database : a Report Prepared by Statistical Consulting Services for KTOI Describing the Key Components and Specifications of the KTOI Relational Database.

Data are the central focus of any research project. Their collection and analysis are crucial to meeting project goals, testing scientific hypotheses, and drawing relevant conclusions. Typical research projects often devote the majority of their resources to the collection, storage and analysis of data. Therefore, issues related to data quality should be of foremost concern. Data quality issues are even more important when conducting multifaceted studies involving several teams of researchers. Without the use of a standardized protocol, for example, independent data collection carried out by separate research efforts can lead to inconsistencies, confusion and errors throughout the larger project. A database management system can be utilized to help avoid all of the aforementioned problems. The centralization of data into a common relational unit, i.e. a relational database, shifts the responsibility for data quality and maintenance from multiple individuals to a single database manager, thus allowing data quality issues to be assessed and corrected in a timely manner. The database system also provides an easy mechanism for standardizing data components, such as variable names and values uniformly across all segments of a project. This is particularly an important issue when data are collected on a number of biological/physical response and …
Date: September 24, 2009
Creator: Shafii, Bahman
Object Type: Report
System: The UNT Digital Library
Metrology Techniques for the Assembly of NCSX (open access)

Metrology Techniques for the Assembly of NCSX

In support of the National Compact Stellerator Experiment (NCSX), stellerator assembly activities continued this past year at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL). The construction program saw the completion of the first two Half Field-Period Assemblies (HPA), each consisting of three modular coils. The full machine includes six such sub-assemblies. A single HPA consists of three of the NCSX modular coils wound and assembled at PPPL. These geometrically-complex threedimensional coils were wound using computer-aided metrology and CAD models to tolerances within +/- 0.5mm. The assembly of these coils required similar accuracy on a larger scale with the added complexity of more individual parts and fewer degrees of freedom for correction. Several new potential positioning issues developed for which measurement and control techniques were developed. To accomplish this, CAD coordinate-based computer metrology equipment and software similar to the solutions employed for winding the modular coils was used. Given the size of the assemblies, the primary tools were both interferometeraided and Absolute Distance Measurement (ADM)-only based laser trackers. In addition, portable Coordinate Measurement Machine (CMM) arms and some novel indirect measurement techniques were employed. This paper will detail both the use of CAD …
Date: September 24, 2009
Creator: C. Priniski, T. Dodson, M. Duco, S. Raftopoulos, R. Ellis, and A. Brooks
Object Type: Article
System: The UNT Digital Library
National Spherical Torus Experiment (NSTX) Center Stack Upgrade (open access)

National Spherical Torus Experiment (NSTX) Center Stack Upgrade

The purpose of the NSTX Center Stack Upgrade project is to expand the NSTX operational space and thereby the physics basis for next-step ST facilities. The plasma aspect ratio (ratio of plasma major to minor radius) of the upgrade is increased to 1.5 from the original value of 1.26, which increases the cross sectional area of the center stack by a factor of ~ 3 and makes possible higher levels of performance and pulse duration.
Date: September 24, 2009
Creator: Neumeyer, C.; Chrzanowski, J.; Dudek, L.; Fan, H.; Hatcher, R.; Heitzenroeder, P. et al.
Object Type: Article
System: The UNT Digital Library
NSTX Protection And Interlock Systems For Coil And Powers Supply Systems (open access)

NSTX Protection And Interlock Systems For Coil And Powers Supply Systems

NSTX at Princeton Plasma Physics Laboratory (PPPL) requires sophisticated plasma positioning control system for stable plasma operation. TF magnetic coils and PF magnetic coils provide electromagnetic fields to position and shape the plasma vertically and horizontally respectively. NSTX utilizes twenty six coil power supplies to establish and initiate electromagnetic fields through the coil system for plasma control. A power protection and interlock system is utilized to detect power system faults and protect the TF coils and PF coils against excessive electromechanical forces, overheating, and over current. Upon detecting any fault condition the power system is restricted, and it is either prevented from initializing or suppressed to de-energize coil power during pulsing. Power fault status is immediately reported to the computer system. This paper describes the design and operation of NSTX's protection and interlocking system and possible future expansion.
Date: September 24, 2009
Creator: X. Zhao, S. Ramakrishnan, J. Lawson, C.Neumeyer, R. Marsala, H. Schneider, Engineering Operations
Object Type: Article
System: The UNT Digital Library
An Overview Of The ITER In-Vessel Coil Systems (open access)

An Overview Of The ITER In-Vessel Coil Systems

ELM mitigation is of particular importance in ITER in order to prevent rapid erosion or melting of the divertor surface, with the consequent risk of water leaks, increased plasma impurity content and disruptivity. Exploitable "natural" small or no ELM regimes might yet be found which extrapolate to ITER but this cannot be depended upon. Resonant Magnetic Perturbation has been added to pellet pacing as a tool for ITER to mitigate ELMs. Both are required, since neither method is fully developed and much work remains to be done. In addition, in-vessel coils enable vertical stabilization and RWM control. For these reasons, in-vessel coils (IVCs) are being designed for ITER to provide control of Edge Localized Modes (ELMs) in addition to providing control of moderately unstable resistive wall modes (RWMs) and the vertical stability (VS) of the plasma.
Date: September 24, 2009
Creator: Heitzenroeder, P. J.; Chrzanowski, J. H.; Dahlgren, F.; Hawryluk, R. J.; Loesser, G. D.; Neumeyer, C. et al.
Object Type: Article
System: The UNT Digital Library
SURFACE GEOPHYSICAL EXPLORATION OF SX TANK FARM AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETICS (open access)

SURFACE GEOPHYSICAL EXPLORATION OF SX TANK FARM AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETICS

This report presents the results of the background characterization of the cribs and trenches surrounding the SX tank farm prepared by HydroGEOPHYSICS Inc, Columbia Energy & Environmental Services Inc and Washington River Protection Solutions.
Date: September 24, 2009
Creator: DA, MYERS; D, RUCKER; M, LEVIT; B, CUBBAGE & C, HENDERSON
Object Type: Report
System: The UNT Digital Library
West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2008 (open access)

West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2008

Annual Site Environmental Report for the West Valley Demonstration Project (WVDP) for Calendar Year 2008. The report summarizes the calendar year (CY) 2008 environmental monitoring program data at the WVDP so as to describe the performance of the WVDP’s environmental management system (EMS), confirm compliance with standards and regulations, and highlight important programs. Monitoring and surveillance of the facilities used by the DOE are conducted to verify protection of the environment, continual improvement, prevention and/or minimization of pollution, public outreach, and stakeholder involvement. In addition to demonstrating compliance with environmental regulations and directives, evaluation of data collected in 2008 continued to indicate that WVDP activities pose no threat to public health or safety, or to the environment.
Date: September 24, 2009
Creator: Division, West Valley Environmental Services LLC (WVES) and URS - Washington
Object Type: Report
System: The UNT Digital Library
21st century locomotive technology: quarterly technical status report 26 (open access)

21st century locomotive technology: quarterly technical status report 26

Parasitic losses due to hybrid sodium battery thermal management do not significantly reduce the fuel saving benefits of the hybrid locomotive. Optimal thermal management trajectories were converted into realizable algorithms which were robust and gave excellent performance to limit thermal excusions and maintain fuel savings.
Date: August 24, 2009
Creator: Salasoo, Lembit & Chandra, Ramu
Object Type: Report
System: The UNT Digital Library
ASCR Science Network Requirements (open access)

ASCR Science Network Requirements

The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science, the single largest supporter of basic research in the physical sciences in the United States. In support of the Office of Science programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In April 2009 ESnet and the Office of Advanced Scientific Computing Research (ASCR), of the DOE Office of Science, organized a workshop to characterize the networking requirements of the programs funded by ASCR. The ASCR facilities anticipate significant increases in wide area bandwidth utilization, driven largely by the increased capabilities of computational resources and the wide scope of collaboration that is a hallmark of modern science. Many scientists move data sets between facilities for analysis, and in some cases (for example the Earth System Grid and the Open Science Grid), data distribution is an essential component of the use of ASCR facilities by scientists. Due to the projected growth in wide area data transfer needs, the …
Date: August 24, 2009
Creator: Dart, Eli & Tierney, Brian
Object Type: Report
System: The UNT Digital Library
Composit, Nanoparticle-Based Anode material for Li-ion Batteries Applied in Hybrid Electric (HEV's) (open access)

Composit, Nanoparticle-Based Anode material for Li-ion Batteries Applied in Hybrid Electric (HEV's)

Lithium-ion batteries are promising energy storage devices in hybrid and electric vehicles with high specific energy values ({approx}150 Wh/kg), energy density ({approx}400 Wh/L), and long cycle life (>15 years). However, applications in hybrid and electric vehicles require increased energy density and improved low-temperature (<-10 C) performance. Silicon-based anodes are inexpensive, environmentally benign, and offer excellent theoretical capacity values ({approx}4000 mAh/g), leading to significantly less anode material and thus increasing the overall energy density value for the complete battery (>500 Wh/L). However, tremendous volume changes occur during cycling of pure silicon-based anodes. The expansion and contraction of these silicon particles causes them to fracture and lose electrical contact to the current collector ultimately severely limiting their cycle life. In Phase I of this project Yardney Technical Products, Inc. proposed development of a carbon/nano-silicon composite anode material with improved energy density and silicon's cycleability. In the carbon/nano-Si composite, silicon nanoparticles were embedded in a partially-graphitized carbonaceous matrix. The cycle life of anode material would be extended by decreasing the average particle size of active material (silicon) and by encapsulation of silicon nanoparticles in a ductile carbonaceous matrix. Decreasing the average particle size to a nano-region would also shorten Li-ion diffusion path and …
Date: August 24, 2009
Creator: Gulbinska, Dr. Malgorzata
Object Type: Report
System: The UNT Digital Library
New Stochastic Annual Limits on Intake for Selected Radionuclides (open access)

New Stochastic Annual Limits on Intake for Selected Radionuclides

Annual limits on intake (ALI) have historically been tabulated by the International Commission on Radiological Protection (e.g., ICRP 1979, 1961) and also by the Environmental Protection Agency (EPA 1988). These compilations have been rendered obsolete by more recent ICRP dosimetry methods, and, rather than provide new ALIs, the ICRP has opted instead to provide committed dose coefficients from which an ALI can be determined by a user for a specific set of conditions. The U.S. Department of Energy historically has referenced compilations of ALIs and has defined their method of calculation in its radiation protection regulation (10 CFDR 835), but has never provided a specific compilation. Under June 2007 amendments to 10 CFR 835, ALIs can be calculated by dividing an appropriate dose limit, either 5-rem (0.05 Sv) effective dose or 50 rem (0.5 Sv) equivalent dose to an individual organ or tissue, by an appropriate committed dose coefficient. When based on effective dose, the ALI is often referred to as a stochastic annual limit on intake (SALI), and when based on the individual organ or tissue equivalent limit, it has often been called a deterministic annual limit on intake (DALI).
Date: August 24, 2009
Creator: Carbaugh, Eugene H.
Object Type: Report
System: The UNT Digital Library
Shielding of External Magnetic Perturbations By Torque In Rotating Tokamak Plasmas (open access)

Shielding of External Magnetic Perturbations By Torque In Rotating Tokamak Plasmas

The imposition of a nonaxisymmetric magnetic perturbation on a rotating tokamak plasma requires energy and toroidal torque. Fundamental electrodynamics implies that the torque is essentially limited and must be consistent with the external response of a plasma equilibrium ƒ = j x B. Here magnetic measurements on National Spherical Torus eXperiment (NSTX) device are used to derive the energy and the torque, and these empirical evaluations are compared with theoretical calculations based on perturbed scalar pressure equilibria ƒ = ∇p coupled with the theory of nonambipolar transport. The measurement and the theory are consistent within acceptable uncertainties, but can be largely inconsistent when the torque is comparable to the energy. This is expected since the currents associated with the torque are ignored in scalar pressure equilibria, but these currents tend to shield the perturbation.
Date: August 24, 2009
Creator: Jong-Kyu Park, Allen H. Boozer, Jonathan E. Menard, Stefan P. Gerhardt, and Steve A. Sabbagh
Object Type: Report
System: The UNT Digital Library