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Pressure Induced Phase Transformation of Pb(Zr(0.95)Ti(0.05))O(3) Based Ceramics: Grain Size Dependence

Description: A substantial decrease in hydrostatic ferroelectric (FE) to antiferroelectric (AFE) transformation pressure was measured for Pb(Zr{sub 0.949}Ti{sub 0.051}){sub 0.989}Nb{sub 0.0182}O{sub 3} ceramics with decreasing grain size. The 150 MPa decrease in hydrostatic FE to AFE transformation pressure over the grain size range of 8.5 {micro}m to 0.7{micro}m was shown to be consistent with enhanced internal stress with decreasing grain size. Further, the Curie Point decreased and the dielectric constan… more
Date: December 21, 1999
Creator: Tuttle, Bruce A.; Voigt, James A.; Scofield, Timothy W.; Aselage, Terrence L.; Rodriguez, Mark A.; Yang, Pin et al.
Partner: UNT Libraries Government Documents Department
open access

Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

Description: Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dim… more
Date: December 21, 1999
Creator: ALAM,TODD M.
Partner: UNT Libraries Government Documents Department
open access

Development of integrated mechanistically-based degradation-mode models for performance assessment of high-level waste containers

Description: Alloy 22 [UNS NO60221] is now being considered for construction of high level waste containers to be emplaced at Yucca Mountain and elsewhere. In essence, this alloy is 20.0-22.5% Cr, 12.5-14.5% MO, 2.0-6.0% Fe, 2.5-3.5% W, with the balance being Ni. Other impurity elements include P, Si, S, Mn, Co and V. Cobalt may be present at a maximum concentration of 2.5%. Detailed mechanistic models have been developed to account for the corrosion of Alloy 22 surfaces in crevices that will inevitably for… more
Date: December 21, 1998
Creator: Estill, J. C.; Farmer, J. C.; Gordon, S. R. & McCright, R. D.
Partner: UNT Libraries Government Documents Department
open access

High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT % Cu alloy.

Description: We have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 x 10{sup {minus}3} dpa and 6.3 x 10{sup {minus}2} dpa at a temperature of {approximately}270 C. In the lower dose material a majority (ca. 60%)of the precipitates visible in high-resolution electron microscopy were timed 9R precipitates of size {approximately}2-4 nm, while ca. 40% were untwinned. In the higher dose material, a majority (ca. 75%) of visible … more
Date: December 21, 1998
Creator: Nicol, A. C.
Partner: UNT Libraries Government Documents Department
open access

Geotechnical Issues in Total System Performance Assessments of Yucca Mountain

Description: A Total System Performance Assessment (TSPA) of Yucca Mountain consists of integrated sub-models and analyses of natural and engineered systems. Examples of subsystem models include unsaturated-zone flow and transport, seepage into drifts, coupled thermal hydrologic processes, transport through the engineered barrier system, and saturated-zone flow and transport. The TSPA evaluates the interaction of important processes among these subsystems, and it determines the impact of these processes on … more
Date: December 21, 1999
Creator: HO,CLIFFORD K.; HOUSEWORTH,JIM & WILSON,MICHAEL L.
Partner: UNT Libraries Government Documents Department
open access

Properties and orientation of antiferroelectric lead zirconate thin films grown by MOCVD.

Description: Single-phase polycrystalline PbZrO{sub 3} (PZ) thin films, 3000-6000 {angstrom} thick, have been grown by metal-organic chemical vapor deposition (MOCVD) on (111)Pt/Ti/SiO{sub 2}/Si substrates at {approximately}525 C. X-ray diffraction analysis indicated that the PZ films grown on (111)Pt/Ti/SiO{sub 2}/Si (Pt/Ti/Si) showed preferred pseudocubic (110) orientation. In contrast, PZ films grown on 150 {angstrom} thick PbTiO{sub 3} (PT) template layers exhibited a pseudocubic (100) preferred orienta… more
Date: December 21, 1998
Creator: Chen, N.
Partner: UNT Libraries Government Documents Department
open access

Fate of neptunium in an anaerobic, methanogenic microcosm.

Description: Neptunium is found predominantly as Np(IV) in reducing environments, but Np(V) in aerobic environments. However, currently it is not known how the interplay between biotic and abiotic processes affects Np redox speciation in the environment. In order to evaluate the effect of anaerobic microbial activity on the fate of Np in natural systems, Np(V) was added to a microcosminoculated with anaerobic sediments from a metal-contaminated fresh water lake. The consortium included metal-reducing, sulfa… more
Date: December 21, 1998
Creator: Banaszak, J. E.
Partner: UNT Libraries Government Documents Department
open access

Incorporation of radionuclides from the electrometallurgical treatment of spent fuel into a ceramic waste form.

Description: An electrometallurgical process is being developed at Argonne National Laboratory to treat spent metallic nuclear fuel. In this process, the spent nuclear fuel is electrorefined in a molten salt to separate uranium from the other constituents of the fuel. The treatment process generates a contaminated chloride salt that is incorporated into a ceramic waste form. The ceramic waste form, a composite of socialite and glass, contains the fission products (rare earths, alkalis, alkaline earth metals… more
Date: December 21, 1998
Creator: Pereira, C.
Partner: UNT Libraries Government Documents Department
open access

Precision measurements at a muon collider

Description: We discuss the potential for making precision measurements of M{sub W} and M{sub T} at a muon collider and the motivations for each measurement. A comparison is made with the precision measurements expected at other facilities. The measurement of the top quark decay width is also discussed.
Date: December 21, 1995
Creator: Dawson, S.
Partner: UNT Libraries Government Documents Department
open access

Defining Requirements for Improved Photovoltaic System Reliability

Description: Reliable systems are an essential ingredient of any technology progressing toward commercial maturity and large-scale deployment. This paper defines reliability as meeting system fictional requirements, and then develops a framework to understand and quantify photovoltaic system reliability based on initial and ongoing costs and system value. The core elements necessary to achieve reliable PV systems are reviewed. These include appropriate system design, satisfactory component reliability, and … more
Date: December 21, 1998
Creator: Maish, A. B.
Partner: UNT Libraries Government Documents Department
open access

Testing and Development of a 30-kVA Hybrid Inverter: Lessons Learned and Reliability Implications

Description: A 30-kVA Trace Technologies hybrid power processor was specified and tested at the Sandia inverter test facility. Trace Technologies involving the control system, in response to suggestions made modifications, primarily by Sandia and Arizona Public Service (APS) personnel. The modifications should make the inverter more universally applicable and less site-specific so that it can be applied in various sites with minimal field interaction required from the design engineer. The project emphasized… more
Date: December 21, 1998
Creator: Ginn, J.W.
Partner: UNT Libraries Government Documents Department
open access

Chemical Solution Processing of Strontium Bismuth Tantalate Films

Description: We describe Chemical Solution Deposition (CSD) processes by which Strontium Bismuth Tantalate (SBT) thin films can be prepared at temperatures as low as 550 C. In this paper, we will present strategies used to optimize the properties of the films including solution chemistry, film composition, the nature of the substrate (or bottom electrode) used, and the thermal processing cycle. Under suitable conditions, {approximately} 1700 {angstrom} films can be prepared which have a large switchable pol… more
Date: December 21, 1998
Creator: Boyle, T.J. & Lakeman, C.D.E.
Partner: UNT Libraries Government Documents Department
open access

Solar Heat-Pipe Receiver Wick Modeling

Description: Stirling-cycle engines have been identified as a promising technology for the conversion of concentrated solar energy into usable electrical power. In previous experimented work, we have demonstrated that a heat pipe receiver can significantly improve system performance-over a directly-illuminated heater head. The design and operating conditions of a heat pipe receiver differ significantly from typical laboratory heat pipes. New wick structures have been developed to exploit the characteristics… more
Date: December 21, 1998
Creator: Andraka, C. E.
Partner: UNT Libraries Government Documents Department
open access

Safe venting of ``red oil`` runaway reactions

Description: Calorimetry testing of Tri-n-butyl phosphate (TBP) saturated with strong nitric acid was performed to determine the relationship between vent size and pressure buildup in the event of a runaway reaction. These experiments show that runaway can occur in an open system, but that even when runaway is induced in the TBP/HN0{sub 3} system, dangerous pressure buildup will be prevented with practical vent size.
Date: December 21, 1994
Creator: Paddleford, D. F. & Fauske, H. K.
Partner: UNT Libraries Government Documents Department
open access

Long-term operating experience for the ATLAS superconducting resonators

Description: Portions of the ATLAS accelerator have been operating now for over 21 years. The facility has accumulated several million resonator-hours of operation at this point and has demonstrated the long-term reliability of RF superconductivity. The overall operating performance of the ATLAS facility has established a level of beam quality, flexibility, and reliability not previously achieved with heavy-ion accelerator facilities. The actual operating experience and maintenance history of ATLAS are pres… more
Date: December 21, 1999
Creator: Pardo, R. & Zinkann, G.
Partner: UNT Libraries Government Documents Department
open access

Neutron transfer kernels in the resonance domain in the harmonic crystal model.

Description: To describe neutron scattering the resonance domain of the nuclear fuel isotopes, the static model is widely in use in nuclear data processing codes. With this model the influence of chemical binding on the transfer cross section is not taken into account since the nucleus is considered to be in rest and isolated in the laboratory system. Further, the application of the free gas model to the resonant scattering of neutrons shows that the up-scattering probability is strongly dependent on the in… more
Date: December 21, 1999
Creator: Naberejnev, D. G.
Partner: UNT Libraries Government Documents Department
open access

Ba{sub 1{minus}x}Sr{sub x}TiO{sub 3} thin film sputter-growth processes and electrical property relationships for high frequency devices

Description: Precise control of Ba{sub 1{minus}x}Sr{sub x}Ti0{sub 3} (BST) film composition is critical for the production of high-quality BST thin films. Specifically, it is known that nonstoichiometry greatly affects the electrical properties of BST film capacitors. The authors are investigating the composition-microstructure-electrical property relationships of polycrystalline BST films produced by magnetron sputter-deposition using a single target with a Ba/Sr ratio of 50/50 and a (Ba+Sr)/Ti ratio of 1.… more
Date: December 21, 1999
Creator: Im, J.; Auciello, O.; Streiffer, S. K.; Baumann, P. K.; Eastman, J. A.; Kaufman, D. Y. et al.
Partner: UNT Libraries Government Documents Department
open access

Disorder-driven nonequilibrium melting studied by electron diffraction, brillouis scattering, and molecular dynamics

Description: In the present paper, a brief overview of the electron diffraction, Brillouin scattering and molecular dynamics studies of radiation-induced amorphization of ordered intermetallic compounds is presented. In these studies, measured changes in the velocity of surface acoustic phonons, lattice constant, and the Bragg-Williams long-range order parameter induced by irradiation were compared with the results of computer simulations of defect-induced amorphization. The results indicate that progressiv… more
Date: December 21, 1999
Creator: Okamoto, P. R.; Lam, N. Q. & Grimsditch, M.
Partner: UNT Libraries Government Documents Department
open access

A beamline matching application based on open source software

Description: An interactive Beamline Matching application has been developed using beamline and automatic differentiation class libraries. Various freely available components were used; in particular, the user interface is based on FLTK, a C++ toolkit distributed under the terms of the GNU Public License (GPL). The result is an application that compiles without modifications under both X-Windows and Win32 and offers the same look and feel under both operating environments. In this paper, we discuss some of … more
Date: December 21, 2000
Partner: UNT Libraries Government Documents Department
open access

Spatial Bias in Field-Estimated Unsaturated Hydraulic Properties

Description: Hydraulic property measurements often rely on non-linear inversion models whose errors vary between samples. In non-linear physical measurement systems, bias can be directly quantified and removed using calibration standards. In hydrologic systems, field calibration is often infeasible and bias must be quantified indirectly. We use a Monte Carlo error analysis to indirectly quantify spatial bias in the saturated hydraulic conductivity, K{sub s}, and the exponential relative permeability paramet… more
Date: December 21, 2000
Creator: HOLT,ROBERT M.; WILSON,JOHN L. & GLASS JR.,ROBERT J.
Partner: UNT Libraries Government Documents Department
open access

Dense optical-electrical interface module

Description: The DOIM (Dense Optical-electrical Interface Modules) is a custom-designed optical data transmission module employed in the upgrade of Silicon Vertex Detector of CDF experiment at Fermilab. Each DOIM module consists of a transmitter (TX) converting electrical differential input signals to optical outputs, a middle segment of jacketed fiber ribbon cable, and a receiver (RX) which senses the light inputs and converts them back to electrical signals. The targeted operational frequency is 53 MHz, a… more
Date: December 21, 2000
Creator: Chang, Paul
Partner: UNT Libraries Government Documents Department
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