SURFING: A Program for Precise Determination of Sample Position in Stress Measurements Via Neutron Diffraction (open access)

SURFING: A Program for Precise Determination of Sample Position in Stress Measurements Via Neutron Diffraction

Precise determination of the specimen position relative to the sampling volume for texture and stress measurements by neutron diffraction is difficult or sometimes impossible using only optical devices due to large or irregular sample dimensions and/or complicated shape of the sampling volume. The knowledge of the shape and size of the sampling volume allows development of a general mathematical model for the intensity variation with a parallelogram-shape sampling volume moving from outside to inside the specimen for both transmission and reflection geometric set-ups. Both fixed slits and radial collimators are options in defining the geometrical setup. The attenuation by the sample also has been taken into account in this model. Experimental results agree well with the model calculations. The program SURFING is based on the model calculation and was written in Labwindows/CVI{copyright}.
Date: August 8, 2000
Creator: Wang, D.-Q.
Object Type: Report
System: The UNT Digital Library
AN ANALYSIS OF THE IMPACT OF SPORTS UTILITY VEHICLES IN THE UNITED STATES (open access)

AN ANALYSIS OF THE IMPACT OF SPORTS UTILITY VEHICLES IN THE UNITED STATES

During the 1990s, sport utility vehicles (SUVs) became the fastest growing segment of the auto industry, especially those in the medium-size category. In 1999, SUV sales reached almost 19% of the total light vehicle market and the mix of SUVs on the road, as measured by registration data, was about 8.7%. This immense popularity has been called by some a passing fad--vehicle purchases based on the SUV ''image''. But the continued yearly increases in SUV sales seem to indicate a more permanent trend. Additional explanations for SUV popularity include the general economic well being in the United States, a perception of safety, and ''utility''. Generally larger and heavier than the typical automobile, SUVs require more fuel per mile to operate and produce greater amounts of pollutants. They are also driven further annually than are automobiles of the same vintage, a fact that exacerbates the fuel-use and emission problems. Although buyers believe that SUVs are safer than automobiles which they are in some cases, SUVs are more prone to roll-overs than are automobiles. In addition, SUVs, with their higher bumpers and greater weight, may be a threat to other vehicles on the highway, especially in side-impact crashes. With sales projected to …
Date: August 16, 2000
Creator: Davis, S.C.
Object Type: Report
System: The UNT Digital Library
NERI PROJECT 99-119."A NEW PARADIGM FOR AUTOMATIC DEVELOPMENT OF HIGHLY RELIABLE CONTROL ARCHITECTURES FOR NUCLEAR POWER PLANTS."PHASE-1 PROGRESS REPORT (open access)

NERI PROJECT 99-119."A NEW PARADIGM FOR AUTOMATIC DEVELOPMENT OF HIGHLY RELIABLE CONTROL ARCHITECTURES FOR NUCLEAR POWER PLANTS."PHASE-1 PROGRESS REPORT

This report describes the tasks performed and the progress made during Phase 1 of the DOE-NERI project number 99-119 entitled ''Automatic Development of Highly Reliable Control Architecture for Future Nuclear Power Plants''. This project is a collaboration effort between the Oak Ridge National Laboratory (ORNL,) The University of Tennessee, Knoxville (UTK) and the North Carolina State University (NCSU). ORNL is the lead organization and is responsible for the coordination and integration of all work. This research focuses on the development of methods for automated generation of control systems that can be traced directly to the design requirements for the life of the plant. Our final goal is to ''capture'' the design requirements inside a ''control engine'' during the design phase. This control engine is, then, not only capable of designing automatically the initial implementation of the control system, but it also can confirm that the original design requirements are still met during the life of the plant as conditions change. This control engine captures the high-level requirements and stress factors that the control system must survive (e.g. a list of transients, or a requirement to withstand a single failure). The control engine, then, is able to generate automatically the control-system …
Date: August 29, 2000
Creator: March-Leuba, J.A.
Object Type: Report
System: The UNT Digital Library
GEOCHEMICAL AND ISOTOPIC CONSTRAINTS ON GROUND-WATER FLOW DIRECTIONS, MIXING AND RECHARGE AT YUCCA MOUNTAIN, NEVADA (open access)

GEOCHEMICAL AND ISOTOPIC CONSTRAINTS ON GROUND-WATER FLOW DIRECTIONS, MIXING AND RECHARGE AT YUCCA MOUNTAIN, NEVADA

This analysis is governed by the Office of Civilian Radioactive Waste Management (OCRWM) Analysis and Modeling Report Development Plan entitled ''Geochemical and Isotopic Constraints on Groundwater Flow Directions, Mixing and Recharge at Yucca Mountain'' (CRWMS M&O 1999a). As stated in this Development Plan, the purpose of the work is to provide an analysis of groundwater recharge rates, flow directions and velocities, and mixing proportions of water from different source areas based on groundwater geochemical and isotopic data. The analysis of hydrochemical and isotopic data is intended to provide a basis for evaluating the hydrologic system at Yucca Mountain independently of analyses based purely on hydraulic arguments. Where more than one conceptual model for flow is possible, based on existing hydraulic data, hydrochemical and isotopic data may be useful in eliminating some of these conceptual models. This report documents the use of geochemical and isotopic data to constrain rates and directions of groundwater flow near Yucca Mountain and the timing and magnitude of recharge in the Yucca Mountain vicinity. The geochemical and isotopic data are also examined with regard to the possible dilution of groundwater recharge from Yucca Mountain by mixing with groundwater downgradient from the potential repository site. Specifically, the …
Date: August 17, 2000
Creator: Meijer, A. & Kwicklis, E.
Object Type: Report
System: The UNT Digital Library
Multiphase fluid flow and subsequent geochemical transport invariably saturated fractured rocks: 1. Approaches (open access)

Multiphase fluid flow and subsequent geochemical transport invariably saturated fractured rocks: 1. Approaches

Reactive fluid flow and geochemical transport in unsaturated fractured rocks has received increasing attention for studies of contaminant transport, groundwater quality, waste disposal, acid mine drainage remediation, mineral deposits, sedimentary diagenesis, and fluid-rock interactions in hydrothermal systems. This paper presents methods for modeling geochemical systems that emphasize: (1) involvement of the gas phase in addition to liquid and solid phases in fluid flow, mass transport and chemical reactions, (2) treatment of physically and chemically heterogeneous and fractured rocks, (3) the effect of heat on fluid flow and reaction properties and processes, and (4) the kinetics of fluid-rock interaction. The physical and chemical process model is embodied in a system of partial differential equations for flow and transport, coupled to algebraic equations and ordinary differential equations for chemical interactions. For numerical solution, the continuum equations are discretized in space and time. Space discretization is based on a flexible integral finite difference approach that can use irregular gridding to model geologic structure; time is discretized fully implicitly as a first-order finite difference. Heterogeneous and fractured media are treated with a general multiple interacting continua method that includes double-porosity, dual-permeability, and multi-region models as special cases. A sequential iteration approach is used to …
Date: August 8, 2000
Creator: Xu, Tianfu & Pruess, Karsten
Object Type: Report
System: The UNT Digital Library
The Chornobyl Accident, Radiation, and Health Concerns (open access)

The Chornobyl Accident, Radiation, and Health Concerns

At 1:23 a.m. on April 26, 1986, an accident at Chernobyl Unit 4, a 1000 MWe RBMK(a)nuclear power plant located in Ukraine, Soviet Union, resulted in destruction of the reactor core and part of the building in which the reactor was housed. In the initial steam explosion and subsequent fires, large amounts of radioactive material were released in the form of gases and dust particles. The energy released in the explosion was equivalent to 40 tons of TNT and resulted in discharge of about 4% of the reactor's nuclear fuel to the environment...
Date: August 30, 2000
Creator: Vargo, George J.
Object Type: Report
System: The UNT Digital Library
NIF optics (open access)

NIF optics

One of the major highlights of the technology development for the National Ignition Facility (NIF) is the optics. NIF will be the largest laser ever built, requiring 7500 large optics (over one foot across) and more than 30,000 small optics. The design, manufacture, and assembly of these important pieces have called for innovative ways to make optics of higher quality than ever before, and to do so at unprecedented speeds. The most obvious role of NIF optics is to steer the 192 laser beams through the 700-foot-long building onto a dime-size laser-fusion target. The less obvious optic roles are using NIF laser glass to create laser light out of normal light, and using KDP crystals to convert that laser light to the correct frequency; both of which are technically challenging requirements. The Optics Processing Laboratory and Optics Assembly Building enable the final preparation and mounting of these amazing optics for their use in NIF.
Date: August 30, 2000
Creator: Parham, T
Object Type: Thesis or Dissertation
System: The UNT Digital Library
NLC photon collider option progress and plans (open access)

NLC photon collider option progress and plans

The idea of producing beams of high energy photons by Compton backscattering of laser photons was proposed over 20 years ago. At the time, producing the required laser pulses was not feasible. However, recent advances in high average power, diode pumped lasers appear to have solved this problem. The US Collaboration is now turning its attention to the engineering requirement of mating the laser and optics components with the accelerator structures in the confined space of the a colliding beam interaction region. The demonstration of a technically feasible interaction region design is planned for the Snowmass conference in 2001.
Date: August 31, 2000
Creator: Gronberg, J.
Object Type: Article
System: The UNT Digital Library
Wireless link design using a patch antenna (open access)

Wireless link design using a patch antenna

A wireless link was designed using a patch antenna. In the process, several different models were tested. Testing proved a patch antenna was a viable solution for building a wireless link within the design specifications. Also, this experimentation provided a basis for future patch antenna design.
Date: August 11, 2000
Creator: Hall, E.
Object Type: Report
System: The UNT Digital Library
Natural-gas-assisted steam electrolysis for distributed hydrogen production (open access)

Natural-gas-assisted steam electrolysis for distributed hydrogen production

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Date: August 29, 2000
Creator: Pham, A. Q.; Haslam, J. J.; Wallman, H.; DiCarlo, J. & Glass, R. S.
Object Type: Article
System: The UNT Digital Library
DARHT-II Downstream Beam Transport Beamline (open access)

DARHT-II Downstream Beam Transport Beamline

This paper describes the mechanical design of the downstream beam transport line for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT II) Facility. The DARHT-II project is a collaboration between LANL, LBNL and LLNL. DARHT II is a 20-MeV, 2000-Amperes, 2-{micro}sec linear induction accelerator designed to generate short bursts of x-rays for the purpose of radiographing dense objects. The downstream beam transport line is approximately 20-meter long region extending from the end of the accelerator to the bremsstrahlung target. Within this proposed transport line there are 15 conventional solenoid, quadrupole and dipole magnets; as well as several specialty magnets, which transport and focus the beam to the target and to the beam dumps. There are two high power beam dumps, which are designed to absorb 80-kJ per pulse during accelerator start-up and operation. Aspects of the mechanical design of these elements are presented.
Date: August 1, 2000
Creator: Westenskow, G A; Bertolini, L R; Duffy, P T & Paul, A C
Object Type: Article
System: The UNT Digital Library
Early-time observations of gamma-ray burst error boxes with the Livermore optical transient imaging system (open access)

Early-time observations of gamma-ray burst error boxes with the Livermore optical transient imaging system

Despite the enormous wealth of gamma-ray burst (GRB) data collected over the past several years the physical mechanism which causes these extremely powerful phenomena is still unknown. Simultaneous and early time optical observations of GRBs will likely make an great contribution t o our understanding. LOTIS is a robotic wide field-of-view telescope dedicated to the search for prompt and early-time optical afterglows from gamma-ray bursts. LOTIS began routine operations in October 1996 and since that time has responded to over 145 gamma-ray burst triggers. Although LOTIS has not yet detected prompt optical emission from a GRB its upper limits have provided constraints on the theoretical emission mechanisms. Super-LOTIS, also a robotic wide field-of-view telescope, can detect emission 100 times fainter than LOTIS is capable of detecting. Routine observations from Steward Observatory's Kitt Peak Station will begin in the immediate future. During engineering test runs under bright skies from the grounds of Lawrence Livermore National Laboratory Super-LOTIS provided its first upper limits on the early-time optical afterglow of GRBs. This dissertation provides a summary of the results from LOTIS and Super-LOTIS through the time of writing. Plans for future studies with both systems are also presented.
Date: August 1, 2000
Creator: Williams, G. G.
Object Type: Report
System: The UNT Digital Library
Large-scale search for dark-matter axions (open access)

Large-scale search for dark-matter axions

We review the status of two ongoing large-scale searches for axions which may constitute the dark matter of our Milky Way halo. The experiments are based on the microwave cavity technique proposed by Sikivie, and marks a ''second-generation'' to the original experiments performed by the Rochester-Brookhaven-Fermilab collaboration, and the University of Florida group.
Date: August 30, 2000
Creator: Kinion, D. & van Bibber, K.
Object Type: Article
System: The UNT Digital Library
Groundwater Monitoring and Tritium-Tracking Plan for the 200 Area State-Approved Land Disposal Site (open access)

Groundwater Monitoring and Tritium-Tracking Plan for the 200 Area State-Approved Land Disposal Site

The 200 Area State-Approved Land Disposal Site (SALDS) is a drainfield which receives treated wastewater, occasionally containing high levels of tritium from treatment of Hanford Site liquid wastes. Only the SALDS proximal wells (699-48-77A, 699-48-77C, and 699-48-77D) have been affected by tritium from the facility thus far; the highest activity observed (2.1E+6 pCi/L) occurred in well 699-48-77D in February 1998. Analytical results of groundwater geochemistry since groundwater monitoring began at the SALDS indicate that all constituents with permit enforcement limits have been below those limits with the exception of one measurement of total dissolved solids (TDS) in 1996. The revised groundwater monitoring sampling and analysis plan eliminates chloroform, acetone, tetrahydrofuran, benzene, and ammonia as constituents. Replicate field measurements will replace laboratory measurements of pH for compliance purposes. A deep companion well to well 699-51-75 will be monitored for tritium deeper in the uppermost aquifer.
Date: August 31, 2000
Creator: Barnett, D. Brent
Object Type: Report
System: The UNT Digital Library
Groundwater Quality Assessment for Waste Management Area U: First Determination (open access)

Groundwater Quality Assessment for Waste Management Area U: First Determination

As a result of the most recent recalculation one of the indicator parameters, specific conductance, exceeded its background value in downgradient well 299-W19-41, triggering a change from detection monitoring to groundwater quality assessment program. The major contributors to the higher specific conductance are nonhazardous constituents (i.e., sodium, calcium, magnesium, chloride, sulfate, and bicarbonate). Nitrate, chromium, and technetium-99 are present and are increasing; however, they are significantly below their drinking waster standards. Interpretation of groundwater monitoring data indicates that both the nonhazardous constituents causing elevated specific conductance in groundwater and the tank waste constituents present in groundwater at the waste management area are a result of surface water infiltration in the southern portion of the facility. There is evidence for both upgradient and waste management area sources for observed nitrate concentrations. There is no indication of an upgradient source for the observed chromium and technetium-99.
Date: August 4, 2000
Creator: Hodges, Floyd N. & Chou, Charissa J.
Object Type: Report
System: The UNT Digital Library
Measurement of the neutron spin structure function at low Q{sup 2} (open access)

Measurement of the neutron spin structure function at low Q{sup 2}

The spin dependent cross sections, {sigma}{sup T}{sub 1/2} and {sigma}{sup T}{sub 3/2}, and asymmetries, A{sub {parallel}} and A{sub {perp}}, for {sup 3}He have been measured at the Jefferson Lab's Hall A facility. The inclusive scattering process {sup 3}{vec He}({vec e},e)X was performed for initial beam energies ranging from 0.86 to 5.1 GeV, at a scattering angle of 15.5°. Data includes measurements from the quasielastic peak, resonance region, and the deep inelastic regime. An approximation for the extended Gcrasimov-Drell-Hcarn integral is presented at a 4-momentum transfer Q{sup 2} of 0.2-1.0 GeV{sup 2} . Also presented are results on the performance of the polarized {sup 3}He target. Polarization of {sup 3}He vvas achieved by the process of spin-exchange collisions with optically pumped rubidium vapor. The {sup 3}He polarization was monitored using the NMR technique of adiabatic fast passage (AFP). The average target polarization was approximately 35% and was determined to have a systematic uncertainty of roughly ±4% relative.
Date: August 1, 2000
Creator: Jensen, John Steffen
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Use of Irrigation to Extend the Seeding Window for Final Reclamation at Yucca Mountain, Nevada (open access)

Use of Irrigation to Extend the Seeding Window for Final Reclamation at Yucca Mountain, Nevada

The U.S. Department of Energy has implemented a program to investigate the feasibility of various techniques for reclaiming lands disturbed during site characterization at Yucca Mountain. As part of this program, two studies were conducted in 1997 to assess the effects of combinations of seeding date (date that seeds are planted) and supplemental irrigation on densities of native plant species at Yucca Mountain. Study objectives were to (1) determine whether the traditional seeding window (October-December) could be extended through combinations of seeding date and irrigation date, (2) determine which combination of seeding date and irrigation was most successful, and (3) assess the effects of irrigation versus natural precipitation on seedling establishment. In the first study, a multi-species seed mix of 16 native species was sown into plots on four dates (12/96, 2/97, 3/97, and 4/97). Irrigation treatments were control (no irrigation) or addition of 80 mm of supplemental water applied over a one month period. Plant densities were sampled in August and again in October, 1997. In the second study, Larrea tridentata and Lycium andersonii, two species that are common at Yucca Mountain, but difficult to establish from seed, were sown together into plots in January and August, 1997. Half …
Date: August 1, 2000
Creator: Safety, TRW Environmental
Object Type: Report
System: The UNT Digital Library
Transition From in-Plane to Out-of-Plane Azimuthal Enhancement in Au+Au Collisions (open access)

Transition From in-Plane to Out-of-Plane Azimuthal Enhancement in Au+Au Collisions

The incident energy at which the azimuthal distributions in semi-central heavy ion collisions change from in-plane to out-of-plane enhancement--E{sub tran} is studied as a function of mass of emitted particles, their transverse momentum and centrality for Au+Au collisions. The analysis is performed in a reference frame rotated with the sidewards flow angle ({Theta}{sub flow}) relative to the beam axis. A systematic decrease of E{sub tran} as function of mass of the reaction products, their transverse momentum and collision centrality is evidenced. The predictions of a microscopic transport model (IQMD) are compared with the experimental results.
Date: August 9, 2000
Creator: Andronic, A.; Stoicea, G.; Petrovici, M.; Simion, V.; Crochet, P.; Alard, J. P. et al.
Object Type: Article
System: The UNT Digital Library
Formation and Reactivity of Biogenic Iron Microminerals (open access)

Formation and Reactivity of Biogenic Iron Microminerals

The overall purpose of the project is to explore and quantify the processes that control the formation and reactivity of biogenic iron microminerals and their impact on the solubility of metal contaminants. The research addresses how surface components of bacterial cells, extracellular organic material, and the aqueous geochemistry of the DIRB microenvironment impacts the mineralogy, chemical state and micromorphology of reduced iron phases.
Date: August 8, 2000
Creator: Beveridge, Terrance J.; Glasauer, Susan; Korenevsky, Anton & Ferris, F. Grant
Object Type: Report
System: The UNT Digital Library
DATA QUALIFICATION REPORT: MAJOR ION AND PH DATA FOR USE ON THE YUCCA MOUNTAIN PROJECT (open access)

DATA QUALIFICATION REPORT: MAJOR ION AND PH DATA FOR USE ON THE YUCCA MOUNTAIN PROJECT

This data qualification report uses technical assessment and corroborating data methods according to Attachment 2 of AP-SIII.2Q, Rev. 0, ICN 2, ''Qualification of Unqualified Data and the Documentation of Rationale for Accepted Data'', to qualify major ion and pH data. This report was prepared in accordance with Data Qualification Plan TDP-NBS-GS-00003 1, Revision 2. Additional reports will be prepared to address isotopic and precipitation-related data. Most of the data considered in this report were acquired and developed by the U.S. Geological Survey (USGS). The data qualification team considers the sampling and analytical protocols employed by the USGS over the time period of data acquisition to be state-of-the-art. The sample collection methodologies have evolved with no significant change that could affect the quality of the data considered in this report into the currently used Hydrologic Procedures that support the Yucca Mountain Project-approved USGS Quality Assurance Program Plan. Consequently, for USGS data, the data collection methods, documentation, and results are reasonable and appropriate in view of standard practice at the time the data were collected. A small number of data sets were collected by organizations other than the USGS and were reviewed along with the other major ion and pH data using …
Date: August 23, 2000
Creator: WILSON, C.; JENKINS, D.M.; STEINBORN, T. & WEMHEUER, R.
Object Type: Report
System: The UNT Digital Library
Preliminary Criticality Safety Evaluation for In Situ Grouting in the Subsurface Disposal Area (open access)

Preliminary Criticality Safety Evaluation for In Situ Grouting in the Subsurface Disposal Area

A preliminary criticality safety evaluation is presented for in situ grouting in the Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory. The grouting materials evaluated are cement and paraffin. The evaluation determines physical and administrative controls necessary to preclude criticality and identifies additional information required for a final criticality safety evaluation. The evaluation shows that there are no criticality concerns with cementitious grout but a neutron poison such as boron would be required for the use of the paraffin matrix.
Date: August 1, 2000
Creator: Slate, Lawrence J & Taylor, Joseph Todd
Object Type: Report
System: The UNT Digital Library
Feasibility of High Resolution P- and S-Wave Seismic Reflection to Detect Methane Hydrate (open access)

Feasibility of High Resolution P- and S-Wave Seismic Reflection to Detect Methane Hydrate

In March, 1999, a combined geophysical field team from the Kansas Geological Survey, Oak Ridge National Laboratory, and the Geological Survey of Canada, performed some experimental high resolution seismic testing at the Mallik drill site in the Mackenzie Delta, Northwest Territories, where drilling and sampling had previously identified gas hydrates at depth beneath a thick permafrost zone. In this information document, we show data from this seismic test, along with comparisons and observations significant to the effective use of high resolution imaging and important considerations about high resolution operations in this environment. Included are discussions and examples based on previous studies at this site, data acquisition, processing, correlation of results with other data sets and some recommendations for future surveying.
Date: August 2, 2000
Creator: Hunter, J.A.
Object Type: Report
System: The UNT Digital Library
CALCULATION: PRECIPITATION CHARACTERISITICS FOR STORM WATER MANAGEMENT (open access)

CALCULATION: PRECIPITATION CHARACTERISITICS FOR STORM WATER MANAGEMENT

This Calculation is intended to satisfy engineering requirements for maximum 60-minute precipitation amounts for 50 and 100-year return periods at and near Yucca Mountain. This data requirement is documented in the ''Interface Control Document for Support Operations to Surface Facilities Operations Functional and Organizational Interfaces'' (CRWMS M&O 1998a). These developed data will supplement the information on 0.1 hour to 6-hour (in 0.1-hour increments) probable maximum precipitation (PMP) presented in the report, ''Precipitation Design Criteria for Storm Water Management'' (CRWMS M&O 1998b). The Reference Information Base (RIB) item, Precipitation ''Characteristics for Storm Water Management'' (M09902RIB00045 .OOO), was developed based on CRWMS M&O (1998b) and will be supplemented (via revision) with the information developed in this Calculation. The ''Development Plan for the Calculation: Precipitation Characteristics for Storm Water Management'' (CRWMS M&O 2000) was prepared in accordance with AP-2.l3Q, ''Technical Product Development Planning''. This calculation was developed in accordance with AP-3.12Q, Rev. O/ICN 2.
Date: August 14, 2000
Creator: Ambos, D.
Object Type: Report
System: The UNT Digital Library
Simplified Plant Analysis Risk (SPAR) Human Reliability Analysis (HRA) Methodology: Comparisons with other HRA Methods (open access)

Simplified Plant Analysis Risk (SPAR) Human Reliability Analysis (HRA) Methodology: Comparisons with other HRA Methods

The 1994 Accident Sequence Precursor (ASP) human reliability analysis (HRA) methodology was developed for the U.S. Nuclear Regulatory Commission (USNRC) in 1994 by the Idaho National Engineering and Environmental Laboratory (INEEL). It was decided to revise that methodology for use by the Simplified Plant Analysis Risk (SPAR) program. The 1994 ASP HRA methodology was compared, by a team of analysts, on a point-by-point basis to a variety of other HRA methods and sources. This paper briefly discusses how the comparisons were made and how the 1994 ASP HRA methodology was revised to incorporate desirable aspects of other methods. The revised methodology was renamed the SPAR HRA methodology.
Date: August 1, 2000
Creator: Byers, James Clifford; Gertman, David Ira; Hill, Susan Gardiner; Blackman, Harold Stabler; Gentillon, Cynthia Ann; Hallbert, Bruce Perry et al.
Object Type: Article
System: The UNT Digital Library