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Investigation of photovoltaic mechanisms in polycrystalline thin-film solar cells. Interim technical report, November 1, 1980-July 31, 1981

Description: Effort is reported on measurement technique development to assess the utility of Deep-Level Transient Spectroscopy (DLTS) methods in characterizing polycrystalline silicon that was deliberately doped with Ti during growth. Difficulties encountered with lateral DLTS measurements are discussed. In this approach, modulation of the grain boundary, double-depletion region produces the entire DLTS signal. Major effort has been applied in grain boundary characterization and control. The most significa… more
Date: March 5, 1982
Creator: Temofonte, T. A.; Szedon, J. R. & O'Keeffe, T. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Silicon-on-ceramic process: silicon sheet growth and device development for the large-area silicon sheet task of the Low-Cost Solar Array Project. Annual report No. 5, September 29, 1979-September 30, 1980

Description: The objective of this research is to investigate the technical feasibility of producing solar-cell-quality sheet silicon to meet the DOE 1986 cost goal of 70 cents/watt. The silicon-on-ceramic approach is to coat a low-cost ceramic substrate with large-grain polycrystalline silicon by unidirectional solidification of molten silicon. Results are reported. A new silicon-coating system, SCIM-II, was designed and constructed. A design strategy to avoid buckling and breaking of substrates has been f… more
Date: January 5, 1981
Creator: Whitehead, A B; Zook, J D; Grung, B L; Heaps, J D; Schmit, F; Schuldt, S B et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Atomistic Modeling of Wave Propagation in Nanocrystals

Description: We present non-equilibrium molecular dynamics (MD) simulations of wave propagation in nanocrystals. We find that the width of the traveling wave front increases with grain size, d, as d{sup 1/2}. This width also decreases with the pressure behind the front. We extrapolate our results to micro-crystals and obtain reasonable agreement with experimental data. In addition, our extrapolation agrees with models that only take into account the various velocities of propagation along different crystall… more
Date: July 5, 2005
Creator: Bringa, E; Caro, A; Victoria, M & Park, N
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Changes in delta-Plutonium due to self-irradiation aging observed by Continuous in-situ X-ray Scattering

Description: The aging in plutonium is predominantly caused by its internal self-irradiation. The self-irradiation in Pu-239 is by the decay process of transmuting the Pu atom into uranium atom and emitting an {alpha}-particle. Most of the lattice damage comes from the uranium recoil resulting in Frenkel-type defects consisting of vacancies and self-interstitial atoms, helium in-growth and defect clusters and possibly even though it is not yet observed, the generation of voids. As part of the stockpile stew… more
Date: January 5, 2007
Creator: Saw, C K; Chung, B W & Wall, M A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Determining the mechanical constitutive properties of metals as a function of strain rate and temperature: A combined experimental and modeling approach

Description: OAK-135 Development and validation of constitutive models for polycrystalline materials subjected to high strain rate loading over a range of temperatures are needed to predict the response of engineering materials to in-service type conditions (foreign object damage, high-strain rate forging, high-speed sheet forming, deformation behavior during forming, response to extreme conditions, etc.). To account accurately for the complex effects that can occur during extreme and variable loading condi… more
Date: January 5, 2004
Creator: Robertson, I. M.; Beaudoin, A. & Lambros, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

Description: This manuscript concerns the application of infrared birefringence imaging (IBI) to quantify macroscopic and microscopic internal stresses in multicrystalline silicon (mc-Si) solar cell materials. We review progress to date, and advance four closely related topics. (1) We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are general… more
Date: May 5, 2010
Creator: Ganapati, Vidya; Schoenfelder, Stephan; Castellanos, Sergio; Oener, Sebastian; Koepge, Ringo; Sampson, Aaron et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Deformation At Crystallite Interfaces

Description: Deformation at grain boundaries is observed and a framework for boundary specific constitutive laws based upon geometric considerations of slip transfer is developed. Orientation images of a pseudo-internal surface during interrupted channel die deformations of a Cu bi-crystal show the heterogeneity of lattice rotation near the grain boundary. The experiments demonstrate that a region near the boundary is strongly influenced by neighboring grain deformation and lend support to the development o… more
Date: October 5, 2001
Creator: Field, D P; Mortensen, A W; Nowell, M M & Campbell, G H
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Singular and nonlinear processes in applied mathematics. Final technical report

Description: A wide range of research topics were supported under this grant. These included: (1) complex space time singularities in nonlinear differential equations; (2) singularities in magneto-hydrodynamics; (3) the dynamics of knots and curves; and (4) the structure and dynamics of foams and grain boundaries. A brief summary of results achieved in each of these four areas is given below along with the associated publications acknowledging DOE support.
Date: August 5, 1998
Creator: Tabor, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Microstructural dependence of cavitation damage in polycrystalline materials. Final report, 1 November 1992--31 October 1994

Description: Microstructure of a sample of Inconel X-750 damaged by ISCC (intergranular stress corrosion cracking) was examined after fatigue precracking in a high-temperature environment of deaerated water. Orientation imaging microscopy was used to reveal the microstructure adjacent to the crack path. General high-angle boundaries were found to be most susceptible to cracking. An ordering of the susceptibilities to ISCC damage was proposed; all boundaries have been classified into one of 12 categories. A … more
Date: February 5, 1996
Creator: Adams, B.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Radiation-induced segregation and the relationship to physical properties in irradiated austenitic alloys.

Description: Radiation-induced changes in composition are studied because these changes can degrade failure of materials irradiated in nuclear reactors. In this work, the effect of alloy composition on radiation-induced segregation, hardening, and void swelling is presented. Five alloys, Fe-18Cr-8Ni, Fe-16Cr-13Ni, Fe-18Cr-40Ni, Fe-16Cr-13Ni+Mo, and Fe-16Cr-13Ni+Mo+P (all compositions in wt. %), were irradiated with 3.2 MeV protons at 400 C to a dose of 0.5 displacements per atom. The change in grain boundar… more
Date: June 5, 2002
Creator: Allen, T. R.; Cole, J. I.; Was, G. S. & Kenik, E. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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