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Program for personnel protection from oxygen deficiency in a Fast Breeder Reactor Test Facility (FFTF) (open access)

Program for personnel protection from oxygen deficiency in a Fast Breeder Reactor Test Facility (FFTF)

The FFTF reactor is described. Procedures and equipment used to protect personnel from potential hazards of oxygen deficient environments are described.
Date: December 12, 1979
Creator: Bell, J.C.
System: The UNT Digital Library
Target plane imaging system for the Nova laser (open access)

Target plane imaging system for the Nova laser

The Nova laser, in operation since December 1984, is capable of irradiating targets with light at 1.05 ..mu..m, 0.53 ..mu..m, and 0.35 ..mu..m. Correct alignment of these harmonic beams uses a system called a target plane imager (TPI). It is a large microscope (four meters long, weighing one thousand kilograms) that relays images from the target chamber center to a video optics module located on the outside of the chamber. Several modes of operation are possible including: near-field viewing and far-field viewing at three magnifications and three wavelengths. In addition, the entire instrument can be scanned in X,Y,Z to examine various planes near chamber center. Performance of this system and its computer controls will be described.
Date: December 12, 1985
Creator: Swift, C. D.; Bliss, E. S.; Jones, W. A.; Reeves, R. J.; Seppala, L. G.; Shelton, R. T. et al.
System: The UNT Digital Library
Large aperture optical switching devices (open access)

Large aperture optical switching devices

We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs.
Date: December 12, 1983
Creator: Goldhar, J. & Henesian, M.A.
System: The UNT Digital Library
Status of tandem mirror theory (open access)

Status of tandem mirror theory

This report contains the text and slides used for the review talk on tandem mirror theory presented at the meeting of the Division of Plasma Physics, A.P.S., Boston, MA, November 12-16, 1979. Topics covered include classical confinement, equilibria, MHD- and micro-stability, radial transport, and thermal barriers.
Date: December 12, 1979
Creator: Baldwin, D.E.
System: The UNT Digital Library
RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE (open access)

RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

The Department of Energy Savannah River Site vitrifies nuclear waste incident to defense programs through its Defense Waste Processing Facility (DWPF). The piping in the DWPF seal pot jumper configuration must withstand the stresses during an unlikely but potential deflagration event, and maintain its safety function for a 20-year service life. Carbon fiber-reinforced epoxy composites (CFR) were proposed for protection and reinforcement of piping during such an event. The proposed CFR materials have been ASME-approved (Section XI, Code Case N-589-1) for post-construction maintenance and is DOT-compliant per 49CFR 192 and 195. The proposed carbon fiber/epoxy composite reinforcement system was originally developed for pipeline rehabilitation and post-construction maintenance in petrochemical, refineries, DOT applications and other industries. The effects of ionizing radiation on polymers and organic materials have been studied for many years. The majority of available data are based on traditional exposures to gamma irradiation at high dose rates ({approx}10,000 Gy/hr) allowing high total dose within reasonable test periods and general comparison of different materials exposed at such conditions. However, studies in recent years have shown that degradation of many polymers are sensitive to dose rate, with more severe degradation often observed at similar or even lower total doses when exposed …
Date: December 12, 2008
Creator: Hoffman, E & Eric Skidmore, E
System: The UNT Digital Library
Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters for polar media (open access)

Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters for polar media

Sayers and Kachanov (1991) defined crack-influence parameters that are shown to be directly related to Thomsen (1986) weak-anisotropy seismic parameters for fractured reservoirs when the crack/fracture density is small enough. These results are then applied to the problem of seismic wave propagation in polar (i.e., non-isotropic) reservoirs having HTI seismic wave symmetry due to the presence of aligned vertical fractures and resulting in azimuthal seismic wave symmetry at the earth's surface. The approach presented suggests one method of inverting for fracture density from wave-speed data. It is also observed that the angular location {theta}{sub ex} of the extreme value (peak or trough) of the quasi-SV-wave speed for VTI occurs at an angle determined approximately by the formula tan{sup 2} {theta}{sub ex} {approx_equal} tan {theta}{sub m} = [(c{sub 33} - c{sub 44})/(c{sub 11}-c{sub 44})]{sup 1/2}, where {theta}{sub m} is an angle determined directly (as shown) from the c{sub ij} elastic stiffnesses, whenever these are known from either quasi-static or seismic wave measurements. Alternatively, {theta}{sub ex} is given in terms of the Thomsen seismic anisotropy parameters by tan {theta}{sub ex} {approx_equal} ([v{sub p}{sup 2}(0)-v{sub s}{sup 2}(0)]/[(1 + 2{epsilon})v{sub p}{sup 2}(0)-v{sub s}{sup 2}(0)]){sup 1/4}, where {epsilon} = (c{sub 11}-c{sub 33})/2c{sub 33}, v{sub p}{sup …
Date: December 12, 2007
Creator: Berryman, James G.
System: The UNT Digital Library
Index Theorem for Topological Excitations on R^3 \times S^1 and Chern-Simons Theory (open access)

Index Theorem for Topological Excitations on R^3 \times S^1 and Chern-Simons Theory

We derive an index theorem for the Dirac operator in the background of various topological excitations on an R{sup 3} x S{sup 1} geometry. The index theorem provides more refined data than the APS index for an instanton on R{sup 4} and reproduces it in decompactification limit. In the R{sup 3} limit, it reduces to the Callias index theorem. The index is expressed in terms of topological charge and the {eta}-invariant associated with the boundary Dirac operator. Neither topological charge nor {eta}-invariant is typically an integer, however, the non-integer parts cancel to give an integer-valued index. Our derivation is based on axial current non-conservation--an exact operator identity valid on any four-manifold--and on the existence of a center symmetric, or approximately center symmetric, boundary holonomy (Wilson line). We expect the index theorem to usefully apply to many physical systems of interest, such as low temperature (large S{sup 1}, confined) phases of gauge theories, center stabilized Yang-Mills theories with vector-like or chiral matter (at S{sup 1} of any size), and supersymmetric gauge theories with supersymmetry-preserving boundary conditions (also at any S{sup 1}). In QCD-like and chiral gauge theories, the index theorem should shed light into the nature of topological excitations responsible for …
Date: December 12, 2008
Creator: Poppitz, Erich & Unsal, Mithat
System: The UNT Digital Library
Disorder and size effects on Kondo interactions and magnetic correlations in CePt2 nanoscrystals (open access)

Disorder and size effects on Kondo interactions and magnetic correlations in CePt2 nanoscrystals

The evolution of the Kondo effect and magnetic correlations with size reduction in CePt{sub 2} nanoparticles (3.1-26 nm) is studied by analysis of the temperature-dependent specific heat and magnetic susceptibility. The antiferromagnetic correlations diminish with size reduction. The Kondo effect predominates at small particle size with trivalent, small Kondo temperature (T{sub K}) magnetic regions coexisting with strongly mixed valent, large T{sub K} nonmagnetic regions. We discuss the role of structural disorder, background density of states and the electronic quantum size effect on the results.
Date: December 12, 2006
Creator: Chen, Y. Y.; Huang, P. H.; Ou, M. N.; Wang, C. R.; Yao, Y. D.; Lee, T. K. et al.
System: The UNT Digital Library
ATLAS Inner Detector Event Data Model (open access)

ATLAS Inner Detector Event Data Model

The data model for event reconstruction (EDM) in the Inner Detector of the ATLAS experiment is presented. Different data classes represent evolving stages in the reconstruction data flow, and specific derived classes exist for the sub-detectors. The Inner Detector EDM also extends the data model for common tracking in ATLAS and is integrated into the modular design of the ATLAS high-level trigger and off-line software.
Date: December 12, 2007
Creator: ATLAS; Akesson, F.; Costa, M. J.; Dobos, D.; Elsing, M.; Fleischmann, S. et al.
System: The UNT Digital Library
Monte Carlo without chains (open access)

Monte Carlo without chains

A sampling method for spin systems is presented. The spin lattice is written as the union of a nested sequence of sublattices, all but the last with conditionally independent spins, which are sampled in succession using their marginals. The marginals are computed concurrently by a fast algorithm; errors in the evaluation of the marginals are offset by weights. There are no Markov chains and each sample is independent of the previous ones; the cost of a sample is proportional to the number of spins (but the number of samples needed for good statistics may grow with array size). The examples include the Edwards-Anderson spin glass in three dimensions.
Date: December 12, 2007
Creator: Chorin, Alexandre J.
System: The UNT Digital Library
A Chemical Approach to 3-D Lithographic Patterning of Si and GeNanocrystals (open access)

A Chemical Approach to 3-D Lithographic Patterning of Si and GeNanocrystals

Ion implantation into silica followed by thermal annealingis an established growth method for Si and Ge nanocrystals. Wedemonstrate that growth of Group IV semiconductor nanocrystals can besuppressed by co-implantation of oxygen prior to annealing. For Sinanocrystals, at low Si/O dose ratios, oxygen co-implantation leads to areduction of the average nanocrystal size and a blue-shift of thephotoluminescence emission energy. For both Si and Ge nanocrystals, atlarger Si/O or Ge/O dose ratios, the implanted specie is oxidized andnanocrystals do not form. This chemical deactivation was utilized toachieve patterned growth of Si and Ge nanocrystals. Si was implanted intoa thin SiO2 film on a Si substrate followed by oxygen implantationthrough an electron beam lithographically defined stencil mask. Thermalannealing of the co-implanted structure yields two-dimensionallypatterned growth of Si nanocrystals under the masked regions. We applieda previously developed process to obtain exposed nanocrystals byselective HF etching of the silica matrix to these patterned structures.Atomic force microscopy (AFM) of etched structures revealed that exposednanocrystals are not laterally displaced from their original positionsduring the etching process. Therefore, this process provides a means ofachieving patterned structures of exposed nanocrystals. The possibilitiesfor scaling this chemical-based lithography process to smaller featuresand for extending it to 3-D patterning is discussed.
Date: December 12, 2005
Creator: Sharp, I. D.; Xu, Q.; Yi, D. O.; Liao, C. Y.; Ager, J. W., III; Beeman, J. W. et al.
System: The UNT Digital Library
Technical Risk Rating of Doe Environmental Projects - 9153 (open access)

Technical Risk Rating of Doe Environmental Projects - 9153

The U.S. Department of Energy's Office of Environmental Management (DOE-EM) was established to achieve the safe and compliant disposition of legacy wastes and facilities from defense nuclear applications. The scope of work is diverse, with projects ranging from single acquisitions to collections of projects and operations that span several decades and costs from hundreds of millions to billions US$. The need to be able to manage and understand the technical risks from the project to senior management level has been recognized as an enabler to successfully completing the mission. In 2008, DOE-EM developed the Technical Risk Rating as a new method to assist in managing technical risk based on specific criteria. The Technical Risk Rating, and the criteria used to determine the rating, provides a mechanism to foster open, meaningful communication between the Federal Project Directors and DOE-EM management concerning project technical risks. Four indicators (technical maturity, risk urgency, handling difficulty and resolution path) are used to focus attention on the issues and key aspects related to the risks. Pressing risk issues are brought to the forefront, keeping DOE-EM management informed and engaged such that they fully understand risk impact. Use of the Technical Risk Rating and criteria during reviews …
Date: December 12, 2008
Creator: Cercy, M.; Ronald Fayfich, R.; Steven P. & Schneider, S.
System: The UNT Digital Library
Acid Catalysis in Basic Solution: A Supramolecular Host PromotesOrthoformate Hydrolysis (open access)

Acid Catalysis in Basic Solution: A Supramolecular Host PromotesOrthoformate Hydrolysis

Though many enzymes can promote chemical reactions by tuning substrate properties purely through the electrostatic environment of a docking cavity, this strategy has proven challenging to mimic in synthetic host-guest systems. Here we report a highly-charged, water soluble, metal-ligand assembly with a hydrophobic interior cavity that thermodynamically stabilizes protonated substrates and consequently catalyzes the normally acidic hydrolysis of orthoformates in basic solution, with rate accelerations of up to 890-fold. The catalysis reaction obeys Michaelis-Menten kinetics, exhibits competitive inhibition, and the substrate scope displays size selectivity consistent with the constrained binding environment of the molecular host. Synthetic chemists have long endeavored to design host molecules capable of selectively binding slow-reacting substrates and catalyzing their chemical reactions. While synthetic catalysts are often site-specific and require certain properties of the substrate to insure catalysis, enzymes are often able to modify basic properties of the bound substrate such as pK{sub a} in order to enhance reactivity. Two common motifs used by nature to activate otherwise unreactive compounds are the precise arrangement of hydrogen-bonding networks and electrostatic interactions between the substrate and adjacent residues of the protein. Precise arrangement of hydrogen bonding networks near the active sites of proteins can lead to well-tuned pK{sub a}-matching, …
Date: December 12, 2007
Creator: Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
System: The UNT Digital Library
Variable High Order Multiblock Overlapping Grid Methods for Mixed Steady and Unsteady Multiscale Viscous Flows (open access)

Variable High Order Multiblock Overlapping Grid Methods for Mixed Steady and Unsteady Multiscale Viscous Flows

Flows containing steady or nearly steady strong shocks in parts of the flow field, and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme even under the multiblock grid or adaptive grid refinement framework. On one hand, sixth-order or higher shock-capturing methods are appropriate for unsteady turbulence with shocklets. On the other hand, lower order shock-capturing methods are more effective for strong steady shocks in terms of convergence. In order to minimize the shortcomings of low order and high order shock-capturing schemes for the subject flows, a multi-block overlapping grid with different orders of accuracy on different blocks is proposed. Test cases to illustrate the performance of the new solver are included.
Date: December 12, 2007
Creator: Sjogreen, B & Yee, H C
System: The UNT Digital Library
DEPARTMENT OF ENERGY SOIL AND GROUNDWATER SCIENCE AND TECHNOLOGY NEEDS, PLANS AND INITIATIVES (open access)

DEPARTMENT OF ENERGY SOIL AND GROUNDWATER SCIENCE AND TECHNOLOGY NEEDS, PLANS AND INITIATIVES

This paper presents the process used by the Department of Energy (DOE) Environmental Management (EM) Program to collect and prioritize DOE soil and groundwater site science and technology needs, develop and document strategic plans within the EM Engineering and Technology Roadmap, and establish specific program and project initiatives for inclusion in the EM Multi-Year Program Plan. The paper also presents brief summaries of the goals and objectives for the established soil and groundwater initiatives.
Date: December 12, 2007
Creator: Aylward, B; V. ADAMS, V; G. M. CHAMBERLAIN, G & T. L. STEWART, T
System: The UNT Digital Library
Synchronization in complex networks (open access)

Synchronization in complex networks

Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.
Date: December 12, 2007
Creator: Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C. & Kurths, J.
System: The UNT Digital Library
TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS (open access)

TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.
Date: December 12, 2008
Creator: Tosten, M & Michael Morgan, M
System: The UNT Digital Library
Risk Reduction Through Use of External Technical Reviews, Technology Readiness Assessments and Technical Risk Ratings - 9174 (open access)

Risk Reduction Through Use of External Technical Reviews, Technology Readiness Assessments and Technical Risk Ratings - 9174

The U.S. Department of Energy's Office of Environmental Management (DOE-EM) was established to achieve the safe and compliant disposition of legacy wastes and facilities from defense nuclear applications. A large majority of these wastes and facilities are 'one-of-a-kind' and unique to DOE. Many of the programs to treat these wastes have been 'first-of-a-kind' and unprecedented in scope and complexity. This has meant that many of the technologies needed to successfully disposition these wastes were not yet developed or required significant re-engineering to be adapted for DOE-EM's needs. The DOE-EM program believes strongly in reducing the technical risk of its projects and has initiated several efforts to reduce those risks: (1) Technology Readiness Assessments to reduce the risks of deployment of new technologies; (2) External Technical Reviews as one of several steps to ensure the timely resolution of engineering and technology issues; and (3) Technical Risk Ratings as a means to monitor and communicate information about technical risks. This paper will present examples of how Technology Readiness Assessments, External Technical Reviews, and Technical Risk Ratings are being used by DOE-EM to reduce technical risks.
Date: December 12, 2008
Creator: Cercy, M.; Steven P.; Schneider, S.; Kurt, D. & Gerdes, K.
System: The UNT Digital Library
Understanding the O4,5 edge structure of actinide metals (open access)

Understanding the O4,5 edge structure of actinide metals

Using electron energy-loss spectroscopy (EELS) and many-electron atomic spectral calculations, we examine the O{sub 4,5} (5d {yields} 5f) edge structure of the ground-state {alpha} phase of Th, U, Np, Pu, Am, and Cm metal. Results show that the dipole-allowed transitions are contained within the giant resonance and that the small pre-peak in the actinide 5d {yields} 5f transition should not be labeled the O{sub 5} peak, but rather the {Delta}S=1 peak. Lastly, we present for the first time the O{sub 4,5} EELS spectra for Np, Am, and Cm metal.
Date: December 12, 2007
Creator: Butterfield, M; Moore, K; der Laan, G v; Wall, M & Haire, D
System: The UNT Digital Library
Reconnection in Spheromak formation and sustainment (open access)

Reconnection in Spheromak formation and sustainment

The Spheromak is a magnetic confinement device that is being explored in both the US and Japanese fusion programs. It is a member of the Compact Torus family of magnetic structures characterized by a set of closed, nested toroidal flux surfaces but without any coils, transformer cores, etc. protruding through the hole in the torus. The Speromak is closely elated to the Reversed Field Pinch (RFP) in that most of the magnetic field is produced by plasma currents flowing along the magnetic field lines (a near force free field) rather than by external coils. The Spheromak has magnetic field components of comparable strength in both the toroidal (azimuthal) and poloidal (in the plane perpendicular to the azimuthal unit vector) directions. The large internal magnetic energy in the Spheromak makes it rich in magnetohydrodynamic phenomena and reconnection, in particular, plays an important role in the formation, resistive decay and instability processes.
Date: December 12, 1983
Creator: Hammer, J. H.
System: The UNT Digital Library
(Theoretical study of pion and kaon photoproduction in nuclei). Final technical report (open access)

(Theoretical study of pion and kaon photoproduction in nuclei). Final technical report

The contract work was initiated by J. Epstein. The emphasis of the proposal was on (a) the continuation of DWIA calculations of the (..gamma..,..pi../sup + -/) reaction in the ..delta..(1232) region with the extension to the (..gamma..,..pi../sup 0/) reaction and (b) the application of the DWIA approach to the (..gamma..,K) reaction. The (..gamma..,..pi../sup 0/) work was intended to be in close collaboration with the experimental studies underway at Bates Linear Accelerator and the (..gamma..,K/sup + -/) calculations are relevant to proposed high duty factor electron accelerators in the 1 to 4 GeV region. DWIA calculations were carried out for coherent (..gamma..,..pi../sup 0/) reactions in /sup 12/C. Although the DWIA approach seems less fundamental than the current ..delta..-hole model calculations, we had hopes that it could be more readily applicable to incoherent reactions leaving the target nucleus in the excited state. Epstein hoped to improve the reliability of the DWIA calculations for coherent (..gamma..,..pi../sup 0/) production by better treatment of the ..delta.. propagating in the nuclear medium. In parallel with the (..gamma..,..pi../sup 0/) work, Epstein carried on an active collaboration with William Donnelly on the (..gamma..,K/sup + -/) problem. They had succeeded in a relatively complete description of the reaction for …
Date: December 12, 1984
Creator: Booth, E.C.
System: The UNT Digital Library
Near spherical illumination of ion-beam and laser targets (open access)

Near spherical illumination of ion-beam and laser targets

A procedure is developed for reducing energy-deposition asymmetry in spherical targets driven directly by ion or laser beams. This work is part of a strategy for achieving illumination symmetry in such targets, which is proposed as an alternative to those in the literature. This strategy allows an axially symmetric placement of beamlets, which would be convenient for some driven or reactor scenarios. It also allows the use of beam currents or energy fluxes and beam transverse profiles to help reduce deposition asymmetry with fewer beamlets. In the ideal limit of thin deposition layers and controlled beam profiles, at most six beamlets are needed for target symmetry.
Date: December 12, 1985
Creator: Mark, J.W.K.
System: The UNT Digital Library
Nonlinear optics with focused x-ray lasers (open access)

Nonlinear optics with focused x-ray lasers

We have investigated the possibility of focusing x-ray lasers with the use of multilayered mirrors or zone plates. The results indicate that x-ray intensities as high as 10{sup 14} W/cm{sup 2} can be achieved by focusing saturated Ne-like x-ray lasers. These intensities should be adequate for studying nonlinear optical phenomena. 9 refs., 2 figs.
Date: December 12, 1990
Creator: DaSilva, L. B.; Muendel, M. H.; Falcone, R. W.; Fields, D. J.; Kortright, J. B.; MacGowan, B. J. et al.
System: The UNT Digital Library
Tilted Thick-Disk Accretion onto a Kerr Black Hole (open access)

Tilted Thick-Disk Accretion onto a Kerr Black Hole

We present the first results from fully general relativistic numerical studies of thick-disk accretion onto a rapidly-rotating (Kerr) black hole with a spin axis that is tilted (not aligned) with the angular momentum vector of the disk. We initialize the problem with the solution for an aligned, constant angular momentum, accreting thick disk around a black hole with spin a/M = J/M{sup 2} = +0.9 (prograde disk). The black hole is then instantaneously tilted, through a change in the metric, by an angle {beta}{sub 0}. In this Letter we report results with {beta}{sub 0} = 0, 15, and 30{sup o}. The disk is allowed to respond to the Lense-Thirring precession of the tilted black hole. We find that the disk settles into a quasi-static, twisted, warped configuration with Lense-Thirring precession dominating out to a radius analogous to the Bardeen-Petterson transition in tilted Keplerian disks.
Date: December 12, 2003
Creator: Fragile, P C & Anninos, P
System: The UNT Digital Library