Metallization of Hydrogen and Other Small Molecules at 100 GPa Pressures (open access)

Metallization of Hydrogen and Other Small Molecules at 100 GPa Pressures

Fluid hydrogen, oxygen, and nitrogen become metallic at 100 GPa (1 Mbar) pressures. Disorder is the primary reason for observing a metal at lower pressures in the fluid than expected for the ordered solid. This metallic transition is similar to those observed in fluid Cs and Rb by Hensel et al. All five undergo a Mott transition from a semiconducting to metallic fluid with the same electrical conductivities. In contrast, water is a proton conductor at pressures up to 200 GPa. Extreme conditions were achieved for {approx}100 ns with a reverberating shock wave generated with a two-stage light-gas gun.
Date: August 17, 2001
Creator: Nellis, W J
Object Type: Article
System: The UNT Digital Library
Wet-Etch Figuring: Optical Surfacing by Controlled Application of Etchant Solution Using the marangoni Effect (open access)

Wet-Etch Figuring: Optical Surfacing by Controlled Application of Etchant Solution Using the marangoni Effect

Wet-etch figuring (WEF), a computer-controlled method for generating arbitrarily shaped optical surfaces using wet chemical etching, has been developed. This method uses applicator geometry and surface tension gradients (the Marangoni Effect) to define and confine the footprint of a wetted etchant zone on the surface. Capillary forces attach the flowing etchant solution to the underside of the optic being figured. No mechanical or thermal stresses or residues are applied to the optic by this process. This enables interferometric measurement of the glass thickness while surfacing, which then controls the placement and dwell time of the wetted zone. The result is a truly deterministic, closed-loop figuring process with a high degree of optical precision. This process can figure sub-millimeter thickness, large-aperture plates or sheets that are very difficult to finish by conventional methods. Automated linear and circular spot etching tools were used to demonstrate surfacing on 380 micron-thick glass sheets, to Strehl better than 0.8, as specified by data array or Zernike polynomials.
Date: May 17, 2001
Creator: Rushford, M. C.; Britten, J. A.; Hoaglan, C. R.; Thomas, I. M.; Summers, L. J. & Dixit, S. D.
Object Type: Article
System: The UNT Digital Library
Simulation of Positronium in Silica Sodalite (open access)

Simulation of Positronium in Silica Sodalite

We find the annihilation rate of positronium (Ps) within silica sodalite. Positron density and the electronic density seen by positrons are compared with a semi-empirical ''free volume'' model.
Date: April 17, 2001
Creator: Hastings, P; Bug, A. L. R. & Sterne, P
Object Type: Article
System: The UNT Digital Library
Kinematics of Gamma-Ray Burst and their Relationship to Afterglows (open access)

Kinematics of Gamma-Ray Burst and their Relationship to Afterglows

A strong correlation is reported between gamma-ray burst (GRB) pulse lags and afterglow jet-break times for the set of bursts (seven) with known redshifts, luminosities, pulse lags, and jet-break times. This may be a valuable clue toward understanding the connection between the burst and afterglow phases of these events. The relation is roughly linear (i.e. doubling the pulse lag in turn doubles the jet break time) and thus implies a simple relationship between these quantities. We suggest that this correlation is due to variation among bursts of emitter Doppler factor. Specifically, an increased speed or decreased angle of velocity, with respect to the observed line-of-site, of burst ejecta will result in shorter perceived pulse lags in GRBs as well as quicker evolution of the external shock of the afterglow to the time when the jet becomes obvious, i.e. the jet-break time. Thus this observed variation among GRBs may result from a perspective effect due to different observer angles of a morphologically homogeneous populations of GRBs. Also, a conjecture is made that peak luminosities not only vary inversely with burst timescale, but also are directly proportional to the spectral break energy. If true, this could provide important information for explaining the …
Date: December 17, 2001
Creator: Salmonson, J D
Object Type: Article
System: The UNT Digital Library
Market Assessment for Capturing Water Conservation Opportunities in the Federal Sector (open access)

Market Assessment for Capturing Water Conservation Opportunities in the Federal Sector

The Department of Energy's Federal Energy Management Program (FEMP) is considering the development of a technology-specific Super-Energy Saving Performance Contract (ESPC) for water conservation. Prior to the development however, FEMP requires the completion of a market assessment to better understand the water conservation opportunities and the strategies available for capturing them. Thus, this market assessment has been undertaken to evaluate the water conservation opportunities and answer the key questions necessary for FEMP to make recommendations on whether or not to proceed with strategies for water conservation primarily through the development of a water conservation technology-specific performance contract.
Date: August 17, 2001
Creator: Parker, Graham B.; McMordie-Stoughton, Katherine L.; Sullivan, Gregory P. & Elliott, Douglas B.
Object Type: Report
System: The UNT Digital Library
Squark Mixing Contributions to CP violating phase gamma (open access)

Squark Mixing Contributions to CP violating phase gamma

We investigate the possibility that the CP violation due to the soft supersymmetry breaking terms in squark mixing can give significant contributions to the various $\gamma$ related parameters in B decays, different from those of the Standard Model. We derive the new limits on $(\delta^u_12)_LL,LR,RR$ and on $(\delta^d_23)_LL,LR,RR$ from the recent data on $D^0$--$\barD^0$ oscillation as well as those on $B_s^0$--$\barB_s^0$ oscillation. We show that, together with all the other constraints, the currents limits on these parameters still allow large contributions to the CP violating phases in $B_s^0$--$\bar{B_s}^0$ as well as $D^0$--$\barD^0$ oscillations which will modify some of the proposed measurements of $\gamma$ parameters in CP violating B decays. However, the current constraints already dictate that the one-loop squark mixing contributions to various B decay amplitudes cannot be competitive with that of the Standard Model (SM), at least for those B decay modes which are dominated the tree level amplitudes within the SM, and therefore they are not significant in contributing to CP asymmetries in the corresponding B decays.
Date: September 17, 2001
Creator: Chang, Darwin; Chang, We-Fu; Keung, Wai-Yee; Sinha, Nita & Sinha, Rahul
Object Type: Article
System: The UNT Digital Library
CHARACTERIZATION OF TANK 5F VERTICAL COOLING COIL LEACHATES FOR SELECT RADIONUCLIDES 2011 (open access)

CHARACTERIZATION OF TANK 5F VERTICAL COOLING COIL LEACHATES FOR SELECT RADIONUCLIDES 2011

Two twenty-four inch samples of vertical sections of the cooling coils from Tank 5F, taken from Riser 1, were made available to SRNL by SRR for leaching and characterization of the leachates for select radionuclide trapped in the corrosion layer on the exterior of the cooling coils. One piece of cooling coil sample was obtained from a section of a vertical cooling coil located above the 45-inch elevation from the tank floor and the other also from a vertical section of a cooling coil located below the 45-inch elevation from the tank floor of Tank 5F. Analysis results from both cooling coils show that the predominant radionuclides contributing to the activity in both coils are strontium-90 and cesium-137. The activities for strontium-90 and cesium-137 in the Tank 5F vertical cooling coil located above the 45-inch elevation of the tank and designated as sample 5-R1-A45 averaged 1.34E-02 {+-} 1.12E-03 and 7.27E-04 {+-} 4.46E-05 Ci/ft{sup 2}, respectively, while the activities for the vertical cooling coil located below the 45-inch elevation of the tank and designated as sample 5-R1-B45 averaged 8.93E-03 {+-} 8.25E-04 for Sr-90 and 8.10E-04 {+-} 6.36E-05 Ci/ft{sup 2} for Cs-137. Other significant activity contributing radionuclides are americium-241 and europium-154/155. With …
Date: August 17, 2001
Creator: Oji, L. & Diprete, D.
Object Type: Report
System: The UNT Digital Library
HORIZONTAL LIFTING OF 5 DHLW/DOE LONG, 12-PWR LONG AND 24-BWR WASTE PACKAGES (open access)

HORIZONTAL LIFTING OF 5 DHLW/DOE LONG, 12-PWR LONG AND 24-BWR WASTE PACKAGES

The objective of this calculation was to determine the structural response of a 12-Pressurized Water Reactor (PWR) Long, a 24-Boiling Water Reactor (BWR) and a 5-Defense High Level Waste/Department of Energy (DHLW/DOE)--Long spent nuclear fuel waste packages lifted in a horizontal position. The scope of this calculation was limited to reporting the calculation results in terms of maximum stress intensities in the trunnion collar sleeves. In addition, the maximum stress intensities in the inner and outer shells of the waste packages were presented for illustrative purposes. The information provided by the sketches (Attachments I, II and III) is that of the potential design of the types of waste packages considered in this calculation, and all obtained results are valid for these designs only. This calculation is associated with the waste package design and was performed by the Waste Package Design Section in accordance with the ''Technical work plan for: Waste Package Design Description for LA'' (Ref. 7). AP-3.12Q, Calculations (Ref. 13), was used to perform the calculation and develop the document.
Date: May 17, 2001
Creator: Brosse, V. de la
Object Type: Report
System: The UNT Digital Library
Multiple Peaks in the Angular Power Spectrum of the CosmicMicrowave Background: Significance and Consequences for Cosmology (open access)

Multiple Peaks in the Angular Power Spectrum of the CosmicMicrowave Background: Significance and Consequences for Cosmology

Three peaks and two dips have been detected in the power spectrum of the cosmic microwave background from the BOOMERANG experiment, at {ell} {approx} 210, 540, 840 and {ell} {approx} 420, 750, respectively. Using model-independent analyses, we find that all five features are statistically significant and we measure their location and amplitude. These are consistent with the adiabatic inflationary model. We also calculate the mean and variance of the peak and dip locations and amplitudes in a large 7-dimensional parameter space of such models, which gives good agreement with the model-independent estimates, and forecast where the next few peaks and dips should be found if the basic paradigm is correct. We test the robustness of our results by comparing Bayesian marginalization techniques on this space with likelihood maximization techniques applied to a second 7-dimensional cosmological parameter space, using an independent computational pipeline, and find excellent agreement: {Omega}{sub tot} = 1.02{sub -0.05}{sup +0.06} vs. 1.04 {+-} 0.05, {Omega}{sub b}h{sup 2} = 0.022{sub -0.003}{sup +0.004} vs. 0.019{sub -0.004}{sup +0.005}, and n{sub s} = 0.96{sub -0.09}{sup +0.10} vs. 0.90 {+-} 0.08. The deviation in primordial spectral index n{sub s} is a consequence of the strong correlation with the optical depth.
Date: May 17, 2001
Creator: de Bernardis, P.; Ade, P. A. R.; Bock, J. J.; Bond, J. R.; Borrill, J.; Boscaleri, A. et al.
Object Type: Article
System: The UNT Digital Library
Unsaturated Zone Flow Patterns and Analysis (open access)

Unsaturated Zone Flow Patterns and Analysis

This Analysis/Model Report (AMR) documents the development of an expected-case model for unsaturated zone (UZ) flow and transport that will be described in terms of the representativeness of models of the natural system. The expected-case model will provide an evaluation of the effectiveness of the natural barriers, assess the impact of conservatism in the Total System Performance Assessment (TSPA), and support the development of further models and analyses for public confidence building. The present models used in ''Total System Performance Assessment for the Site Recommendation'' (Civilian Radioactive Waste Management System Management and Operating Contractor (CRWMS M&O) 2000 [1532461]) underestimate the natural-barrier performance because of conservative assumptions and parameters and do not adequately address uncertainty and alternative models. The development of an expected case model for the UZ natural barrier addresses issues regarding flow-pattern analysis and modeling that had previously been treated conservatively. This is in line with the Repository Safety Strategy (RSS) philosophy of treating conservatively those aspects of the UZ flow and transport system that are not important for achieving regulatory dose (CRWMS M&O 2000 [153246], Section 1.1.1). The development of an expected case model for the UZ also provides defense-in-depth in areas requiring further analysis of uncertainty and …
Date: October 17, 2001
Creator: Ahlers, C.
Object Type: Report
System: The UNT Digital Library
Input and Results of the Base Case Saturated Zone Flow and Transport Model for TSPA (open access)

Input and Results of the Base Case Saturated Zone Flow and Transport Model for TSPA

None
Date: October 17, 2001
Creator: Arnold, B. W.
Object Type: Report
System: The UNT Digital Library
Analysis of Maximum Reasonably Foreseeable Accidents for the Yucca Mountain Draft Environmental Impact Statement (DEIS) (open access)

Analysis of Maximum Reasonably Foreseeable Accidents for the Yucca Mountain Draft Environmental Impact Statement (DEIS)

Accidents could occur during the transportation of spent nuclear fuel and high-level radioactive waste. This paper describes the risks and consequences to the public from accidents that are highly unlikely but that could have severe consequences. The impact of these accidents would include those to a collective population and to hypothetical maximally exposed individuals (MEIs). This document discusses accidents with conditions that have a chance of occurring more often than 1 in 10 million times in a year, called ''maximum reasonably foreseeable accidents''. Accidents and conditions less likely than this are not considered to be reasonably foreseeable.
Date: August 17, 2001
Creator: Ross, S. B.; Best, R. E.; Maheras, S. J. & McSweeney, T. I.
Object Type: Report
System: The UNT Digital Library
Real Data for Real Routes (open access)

Real Data for Real Routes

None
Date: August 17, 2001
Creator: Best, Ralph; Maheras, S. J.; McSweeney, T. I. & Ross, S. B.
Object Type: Report
System: The UNT Digital Library
Design of Storage Systems Using Multiple Storage Technologies in Renewable Systems (open access)

Design of Storage Systems Using Multiple Storage Technologies in Renewable Systems

Energy systems that rely on intermittent renewable sources typically use storage devices to improve their reliability. Large scale systems can be expected to cycle the storage capacity on cycles ranging from a day to a year. It can be cost effective to use several storage technologies as a system. A very efficient technology can be used for the smaller daily cycles even if it has a high capital cost. Conversely, a technology having a low efficiency but a low capital cost can be used for the larger longer period cycles. This paper presents a method for determining the optimal capacities for a set of storage technologies. It is analogous to techniques used in electric generation capacity planning that use a load duration curve along with the capital and operating costs of various generations technologies. Here we derive a function that describes throughput as a function of capacity and use it along with the capital and operating costs (including efficiencies) of the storage technologies to derive the optimal capacities.
Date: January 17, 2001
Creator: Lamont, A.
Object Type: Report
System: The UNT Digital Library
Prediction of External Corrosion for Steel Cylinders 2001 Report (open access)

Prediction of External Corrosion for Steel Cylinders 2001 Report

The United States Department of Energy (DOE) currently manages the UF{sub 6} Cylinder Project. The project was formed to maintain and safely manage the depleted uranium hexafluoride (UF{sub 6}) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the ETTP site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1997a) delineates the requirements of the project. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1997b). This report documents activities that in whole or in part satisfy specific requirements and actions stated in the UF{sub 6} Cylinder Project SRD and SEMP with respect to forecasting cylinder conditions. The results presented here supercede those presented previously (Lyon 1995, 1996, 1997, 1998, 2000). Many of the wall thickness projections made in this report are conservative, because they are based on the assumption that corrosion trends will continue, despite activities such as improved monitoring, relocations to better storage, and painting.
Date: September 17, 2001
Creator: Schmoyer, RLS
Object Type: Report
System: The UNT Digital Library
Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies (open access)

Aluminum-Oxide Temperatures on the Mark VB, VE, VR, 15, and Mark 25 Assemblies

The task was to compute the maximum aluminum-oxide and oxide-coolant temperatures of assemblies cladded in 99 plus percent aluminum. The assemblies considered were the Mark VB, VE, V5, 15 and 25. These assemblies consist of nested slug columns with individual uranium slugs cladded in aluminum cans. The CREDIT code was modified to calculate the oxide film thickness and the aluminum-oxide temperature at each axial increment. The information in this report will be used to evaluate the potential for cladding corrosion of the Mark 25 assembly.
Date: July 17, 2001
Creator: Aleman, S. E.
Object Type: Report
System: The UNT Digital Library
Shipping Cask Studies with MOX Fuel (open access)

Shipping Cask Studies with MOX Fuel

Tasks of nuclear safety assurance for storage and transport of fresh mixed uranium-plutonium fuel of the VVER-1000 reactor are considered in the view of 3 MOX LTAs introduction into the core. The precise code MCU that realizes the Monte Carlo method is used for calculations.
Date: May 17, 2001
Creator: Pavlovichev, A.M.
Object Type: Report
System: The UNT Digital Library
DOE Safety Metrics Indicator Program (SMIP) Third Quarter FY 2001 Quarterly Report (open access)

DOE Safety Metrics Indicator Program (SMIP) Third Quarter FY 2001 Quarterly Report

The Safety Metrics Indicator Program (SMIP) retrieved 69 packaging- or transportation-related occurrences from the Occurrence Reporting and Processing System (ORPS) during the period from April 1 through June 30, 2001. Only those incidents that occur in preparation for transport, during transport, and during unloading of hazardous material are considered as packaging- or transportation-related occurrences. Other incidents with packaging and transportation (P and T) significance but not involving hazardous material (such as vehicle accidents or empty packagings) are not rated to the SMIP criteria, but are archived in the SMIP Subsidiary Database of occurrences, a sub-database of the main SMIP P and T Occurrence Database. Fifty-one of the originally-selected 69 occurrences were appropriate for classification to the SMIP criteria, 26 of which have offsite applicability. Eight of the original 69 reports are archived in a subsidiary database because they either do not involve the transport of hazardous material or they do not involve transport by vehicle, plane, boat, or rail. The others were either deleted because more thorough review revealed that they were not strictly related to P and T or they were canceled by the reporting site and removed from the ORPS. The number and severity of the selected occurrence …
Date: September 17, 2001
Creator: Dickerson, Leonard S.
Object Type: Report
System: The UNT Digital Library
A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems (open access)

A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems

In this paper we present a model for the short (< second) population of gamma-ray bursts (GRBs). In this model heated neutron stars in a close binary system near their last stable orbit emit neutrinos at large luminosities ({approx} 10{sup 53} ergs/sec). A fraction of these neutrinos will annihilate to form an e{sup +}e{sup -} pair plasma wind which will, in turn, expand and recombine to photons which make the gamma-ray burst. We study neutrino annihilation and show that a substantial fraction ({approx}1/2) of energy deposited comes from inter-star neutrinos, where each member of the neutrino pair originates from each neutron star. Thus, in addition to the annihilation of neutrinos blowing off of a single star, we have a new source of baryon free energy that is deposited between the stars. To model the e{sup +}e{sup -} pair plasma wind between stars, we do three-dimensional relativistic numerical hydrodynamic calculations. Preliminary results are also presented of new, fully general relativistic calculations of gravitationally attracting stars falling from infinity with no angular momentum. These simulations exhibit a compression effect.
Date: December 17, 2001
Creator: Salmonson, J. D. & Wilson, J. R.
Object Type: Article
System: The UNT Digital Library
HRTEM image simulations for the study of ultra-thin gate oxides (open access)

HRTEM image simulations for the study of ultra-thin gate oxides

We have performed high resolution transmission electron microscope (HRTEM) image simulations to qualitatively assess the visibility of various structural defects in ultra-thin gate oxides of MOSFET devices, and to quantitatively examine the accuracy of HRTEM in performing gate oxide metrology. Structural models contained crystalline defects embedded in an amorphous 16 {angstrom}-thick gate oxide. Simulated images were calculated for structures viewed in cross-section. Defect visibility was assessed as a function of specimen thickness and defect morphology, composition, size and orientation. Defect morphologies included asperities lying on the substrate surface, as well as ''bridging'' defects connecting the substrate to the gate electrode. Measurements of gate oxide thickness extracted from simulated images were compared to actual dimensions in the model structure to assess TEM accuracy for metrology. The effects of specimen tilt, specimen thickness, objective lens defocus and coefficient of spherical aberration (C{sub s}) on measurement accuracy were explored for nominal 10{angstrom} gate oxide thickness. Results from this work suggest that accurate metrology of ultra-thin gate oxides (i.e. limited to several per cent error) is feasible on a consistent basis only by using a C{sub s}-corrected microscope. However, fundamental limitations remain for characterizing defects in gate oxides using HRTEM, even with the new …
Date: July 17, 2001
Creator: Taylor, Seth T.; Mardinly, John & O'Keefe, Michael A.
Object Type: Article
System: The UNT Digital Library
DESIGN OF THE SEALEVEL SUSPENDED SOLIDS CONCENTRATION MONITORING SYSTEM (open access)

DESIGN OF THE SEALEVEL SUSPENDED SOLIDS CONCENTRATION MONITORING SYSTEM

The SEAlevel project between Science & Engineering Associates, Inc. (SEA) and the National Energy Technology Laboratory (NETL) in Morgantown, WV (contract DE-AC21-96MC33126) began in direct response to a need expressed by personnel involved with monitoring fluid levels in underground storage tanks at the Hanford Tank Farms. Hanford expressed a desire for an automated monitoring system that could be installed into tanks through liquid observation wells (LOWs). The LOWs are pipes that run from the surface above the tank to the bottom of the tank. The end of the LOW pipe in the tank waste is sealed. Therefore, the LOW provides a clean conduit through which sensors and monitors can be lowered into the tanks. When the SEAlevel project first began, it was understood that the LOWs would be of steel construction, because several existing LOWs at the time were steel pipes and the plans for all future LOW installations were to be with steel pipes. Based on this assumption the SEAlevel monitoring system was to be made using an array of acoustic sensors. However, during the course of the project it was learned that many existing LOWs are of fiberglass construction and that it was the desire of the Tanks …
Date: September 17, 2001
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final report (Grant No. DOE DE-FG02-97ER62366) [Retrieval of cloud fraction and type using broadband diffuse and total shortwave irradiance measurements] (open access)

Final report (Grant No. DOE DE-FG02-97ER62366) [Retrieval of cloud fraction and type using broadband diffuse and total shortwave irradiance measurements]

The primary research effort supported by Grant No. DOE DEFG02-97ER62366 titled ''Retrieval of Cloud Fraction and Type Using Broadband Diffuse and Total Shortwave Irradiance Measurements'' was application of clear-sky identification and cloud fraction estimation algorithms developed by Charles N. Long and Thomas P. Ackerman to the downwelling total, direct and diffuse shortwave irradiance measurements made at all of the central, boundary, and extended facilities of the DOE Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SOP) site. Goals of the research were finalization and publication of the two algorithms in the peer-reviewed literature and operational application of them to all of aforementioned data streams from the ARM SGP site. The clear-sky identification algorithm was published as Long and Ackerman (2000) in the Journal of Geophysical Research, while a description of the cloud fraction estimation algorithm made it to the scientific literature as Long et al. (1999) in the Proceedings of the 10th American Meteorological Association Conference on Atmospheric Radiation held in Madison, Wisconsin. The cloud fraction estimation algorithm relies on empirical relationships between the outputs of the clear-sky identification algorithm and cloud fraction; as such, the cloud fraction estimation algorithm requires significant amounts of data both to properly develop the …
Date: May 17, 2001
Creator: Clothiaux, Eugene
Object Type: Report
System: The UNT Digital Library
High speed DNA sequence analysis by matrix-assisted laser desorption mass spectrometry. Final report for period February 15, 1991 - February 14, 2001 (open access)

High speed DNA sequence analysis by matrix-assisted laser desorption mass spectrometry. Final report for period February 15, 1991 - February 14, 2001

This grant had as its focus (i) to develop chemistry and enzymology to permit the enzymatic synthesis of 2' fluoro modified Sanger sequencing reactions, which would be resistant to fragmentation during MALDI process, (ii) to develop rapid MALDI analyses of DNA sequence polymorphisms using Peptide Nucleic Acid (PNA) DNA analogs in conjunction with solid phase chemistry (iii) to study the fundamental mechanisms occurring in the MALDI analysis of nucleic acids.
Date: April 17, 2001
Creator: Smith, Lloyd M.
Object Type: Report
System: The UNT Digital Library
ANL-W RH-TRU : the remote treatment facility. (open access)

ANL-W RH-TRU : the remote treatment facility.

None
Date: October 17, 2001
Creator: Russ, W. R.; Duncan, D. S. & Grant, R. P.
Object Type: Article
System: The UNT Digital Library