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in subjects: "Crystal Structure"

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Rigid muffin-tin approximation for the electron-phonon interaction in transition metals

Progress in calculating the electron-phonon parameters of transition metals has been based on either the rigid muffin-tin approximation (RMTA) or the fitted modified tight-binding approximation (FMTBA). The RMTA has been shown to be remarkably accurate for average electron-phonon properties, but there are indications that RMTA matrix elements may be too small at low momentum transfer. An attempt is made to demonstrate these assertions concerning the accuracy of RMTA and the numerous electron-ph… more

Date: January 1, 1980

Creator: Butler, W. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Assessment of light water reactor fuel damage during a reactivity initiated accident

This paper presents an assessment of LWR fuel damage during a reactivity initiated accident and comments on the adequacy of the present USNRC design requirements. Results from early SPERT tests are reviewed and compared with results from recent computer simulations and PBF tests. A progression of fuel rod and cladding damage events is presented. High strain rate deformation of relatively cool irradiated cladding early in the transient may result in fracture at a radial average peak fuel enthalp… more

Date: January 1, 1980

Creator: MacDonald, P. E.; Seiffert, S. L.; Martinson, Z. R.; McCardell, R. K.; Owen, D. E. & Fukuda, S. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Recovery of deformed and hydrogen-charge palladium

Positron lifetime and Doppler-broadening studies made at 300 K have been used to investigate the interaction between interstitial hydrogen and lattice defects in deformed Pd. Specimens were charged with hydrogen at 300 K to levels up to 0.1%. The presence of hydrogen was found to have no effect on the recovery curves of Pd upon annealing to 400/sup 0/C. By 400/sup 0/C the values for both lifetime and Doppler-broadening for both cold worked and cold worked plus hydrogen were below the values obt… more

Date: January 1, 1982

Creator: Snead, C. L. Jr.; Lynn, K. G. & Lynch, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Sintering of polycrystalline ionic conductors:. beta. ''-Al/sub 2/O/sub 3/ and NASICON

The densification kinetics for both ..beta..''-alumina and NASICON are dramatically different. ..beta..''-Alumina sinters by a reactive liquid process whereas NASICON densifies by a solid state method. More importantly, a qualitative examination of particle and agglomerate distributions, phase composition, linear shrinkage analysis, and heating rate effects can result in a concise determination of sintering processes without recourse to more quantitative techniques. Such a s… more

Date: January 1, 1979

Creator: McEntire, B. J.; Miller, G. R. & Gordon, R. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

(Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.

Date: October 1, 1991

Item Type: Report

Partner: UNT Libraries Government Documents Department

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X-ray measurements of stresses and defects in EFG and large grained polycrystalline silicon ribbons. First quarterly report

The first model of a modified Bond goniometer has been built and tested for the precision measurement of interplanar spacings in Si-single crystals. A change in interplanar spacing ..delta..d/d approximately = to +- 10/sup -5/ can be detected which corresponds to surface stresses of the order of +- 1000 psi. A second version of the goniometer is being assembled incorporating a removable microscope for precision alignment of the Si-strip into the primary X-ray beam.

Date: January 1, 1978

Creator: Wagner, C.N.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Interaction of noble-metal fission products with pyrolytic silicon carbide

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-… more

Date: January 1, 1982

Creator: Lauf, R. J. & Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Investigation of joining techniques for advanced austenitic alloys

Modified Alloys 316 and 800H, designed for high temperature service, have been developed at Oak Ridge National Laboratory. Assessment of the weldability of the advanced austenitic alloys has been conducted at the University of Tennessee. Four aspects of weldability of the advanced austenitic alloys were included in the investigation.

Date: May 1, 1991

Creator: Lundin, C. D.; Qiao, C. Y. P.; Kikuchi, Y.; Shi, C. & Gill, T. P. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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(The relationship between microstructure and magnetic properties in high-energy permanent magnets characterized by polytwinned structures)

This report summarizes the results of a study of the relationship between microstructure and magnetic properties in a unique genre of ferromagnetic material characterized by a polysynthetically twinned structure which arises during solid state transformation. These results stem from the work over a period of approximately 27 months of a nominal 3 year grant period. The report also contains a proposal to extend the research project for an additional 3 years. The polytwinned structures produce an… more

Date: January 1, 1992

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Magnetic measurements of the transuranium elements. Progress report, January 1-December 31, 1986

Magnetic measurements have been made on polycrystalline CfCl/sub 3/ in both a hexagonal and orthorhombic crystal form. The magnetic properties were studied as a function of crystal structure by converting the same sample back and forth from one form to the other. In a continuation of a study of the magnetic transition temperature as a function of actinide-actinide separation of the curium pnictide series we have undertaken magnetic measurements on curium bismuthide during this contract period. … more

Date: September 1, 1986

Creator: Nave, S.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Radiation-induced segregation in HT-9 martensitic steel

Miniature notched-bar specimens of normalized and tempered HT-9 were neutron irradiated to approx.13 dpa and broken at liquid nitrogen temperatures in a UHV chamber. Fracture surfaces were analyzed using scanning Auger electron spectroscopy. Following irradiation at 410/sup 0/C, the fracture surface contained a small number of large relatively smooth facets, which are thought to be prior austenite grain boundaries. Strong segregation of Ni, Cr, Si, and P was detected at these surfaces, the rema… more

Date: January 1, 1986

Creator: Clausing, R.E.; Heatherly, L.; Faulkner, R.G.; Rowcliffe, A.F. & Farrell, K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Indium phosphide/cadmium sulfide thin-film solar cells. Quarterly technical progress report No. 3, December 1979-April 1980

Thin films (approx. 1 ..mu..m thick) and large grains (approx. 40 x 40 ..mu..m) of InP were epitaxially deposited on low-cost recrystallized CdS (RXCdS) substrates at 280/sup 0/C by planar reactive deposition. At 380/sup 0/C, a 0.4- to 1.0-..mu..m-thick In-Cd-S transition layer between the InP and the RXCdS degrades the quality of the InP epitaxy. However, p-type InP films were prepared at this temperature by Be-doping and capping the entire RXCdS substrate with InP. Large grains of CdTe (appro… more

Date: June 1, 1980

Creator: Zanio, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Devil's staircase and order without periodicity in classical condensed matter

The existence of incommensurate structures proves that crystal ordering is not always the most stable one for nonquantum matter. Some properties of structures which are obtained by minimizing a free energy are investigated in the Frenkel Kontorova and related models. It is shown that an incommensurate structure can be either quasi-sinusoidal with a phason mode or built out of a sequence of equidistant defects (discommensurations) which are locked to the lattice by the Peierls force. In that sit… more

Date: January 1, 1982

Creator: Aubry, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ceramic microstructures and their elucidation by imaging, diffraction and spectroscopic methods

The development and potential utilization of ceramic materials is dependent on a systematic effort involving processing, characterization and appropriate property measurements. The methods of characterization are numerous and it is important to employ the one that is appropriate to the problem both in terms of its information content and the achievable level of resolution. With the incorporation of fine probe forming capabilities in a transmission electron microscope and the development of rela… more

Date: February 1, 1992

Creator: Kirshnan, K.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Hydrogen embrittlement of austenitic stainless steels

No Description Available.

Date: January 1, 1974

Creator: Louthan, M. R. Jr.; Rawl, D. E. Jr.; Donovan, J. A. & Holmes, W. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Metals and Ceramics Division. Annual progress report, ending June 30, 1980

Research is reported concerning: (1) engineering materials, including materials compatibility, mechanical properties, nondestructive testing, pressure vessel technology, and welding and brazing; (2) fuels and processes consisting of ceramic technology, fuel cycle technology, fuels evaluation, fuel fabrication and metals processing; and (3) materials science which includes, ceramic studies, physical metallurgy properties, radiation effects and microstructural analysis, metastable and superconduc… more

Date: September 1, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Ceramic technology for Advanced Heat Engines Project

Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine… more

Date: July 1, 1991

Creator: Johnson, D. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Photophoresis and the scattering of electromagnetic radiation

Electron-microscope photographs of soot lend support to the picture in which a soot particle is modeled as a collection of chains of small carbon spheres. The soot particle itself is typically considerably larger than the small carbon spheres making up the chains. Thus the soot particles might have a size approx.0.1 - 1 ..mu..m while the small carbon spheres might have a size approx.0.03 ..mu..m in typical situations. Further, measurements of the density of soot yield values much less than that… more

Date: September 1, 1985

Creator: Ipser, J.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Neutron diffraction study of magnetic order in the ternary superconductor ErMo/sub 6/Se/sub 8/

Synthesis of new classes of ternary superconducting materials has led to compounds which also show a strong tendency toward magnetic order when one of the constituent elements is a rare earth. Powder neutron diffraction data on superconducting (T/sub s/ approximately 6 K) samples of ErMo/sub 6/Se/sub 8/ taken in the temperature range 0.05 to 2.0 K show that magnetic Bragg peaks develop at T/sub M/ = 1.1 K, in agreement with specific heat studies. However, it is not possible to index these new r… more

Date: 1977~

Creator: Lynn, J. W.; Moncton, D. E.; Shirane, G.; Thomlinson, W.; Eckert, J. & Shelton, R. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Mechanism for Diffusion Induced Grain Boundary Migration

Grain boundaries are found to migrate under certain conditions when solute atoms are diffused along them. This phenomenon, termed diffusion induced grain boundary migration (DIGM), has now been found in six systems. The observed phenomenon and empirical data are used to discard certain concepts for the driving force and the mechanism. A mechanism is proposed in which differences in the diffusion coefficients of the diffusing species along the grain boundary cause a self-sustaining climb of grai… more

Date: August 1, 1980

Creator: Balluffi, R. W. & Cahn, J. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Influence of compositional modifications on the corrosion of iron aluminides of molten nitrate salts

The corrosion of iron-aluminum alloys by molten nitrate salt as a function of aluminum, chromium, and other minor elements has been studied as part of an alloy design effort aimed at the development of a strong, ductile, corrosion-resistant FeAl type of aluminide. Short- term weight change data were used to examine the compositional dependence of the corrosion processes that occurred upon exposure of iron aluminides to highly oxidizing nitrate salts of 650{degrees}C. Corrosion resistance was fo… more

Date: January 1, 1991

Creator: Tortorelli, P. F. & Bishop, P. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Microscopic theory of charges density wave instability in NbSe/sub 2/

The microscopic theory of Sinha and Harmon for electronically driven lattice instabilities is used to explain the ''Kohn-like'' anomalies in the ..sigma../sub 1/ phonon branch and the observed incommensurate superlattice Bragg peak in 2H-NbSe/sub 2/, characteristic of the charge density wave at low temperatures in the neutron scattering experiments of Moncton et al. In accordance with the APW and LCAO band-structure calculations of Mattheiss of 2H-NbSe/sub 2/, the presence o… more

Date: January 1, 1977

Creator: Das, S G; Sinha, S K & Wakabayashi, N

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of Au on the reliability of fine pitch surface mount solder joints

The effect of Au on the reliability of 0.65 mm pitch surface mount solder joints between plastic quad flat packs and Cu-Ni-Au FR-4 printed circuit boards was investigated. Cu-Ni-Au is a desirable printed circuit board finish for multi-chip modules or printed circuit boards that would otherwise require a selective Au finish, for example for edge connectors or wire bondable parts. However, Au is known to embrittle solder when it is present in sufficiently high concentrations, creating a concern t… more

Date: May 1, 1991

Creator: Glazer, J. (Hewlett-Packard Co., Palo Alto, CA (United States)); Kramer, P. & Morris, J.W. Jr. (Lawrence Berkeley Lab., CA (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Elastic constants and the structural phase transition in La sub 2-x Sr sub x CuO sub 4

Resonant ultrasound spectroscopy is used to measure the temperature dependence of all six elastic moduli of La{sub 2-x}Sr{sub x}CuO{sub 4}. A giant softening (> 50% reduction) in the in-plane shear modulus, c{sub 66}, is observed and is attributed to the tetragonal-orthorhombic structural phase transition in this material. This phase transition and the corresponding softening is examined with a simple anharmonic mechanical model and a macroscopic Ginsburg-Landau formalism exploiting the full sy… more

Date: January 1, 1991

Creator: Sarrao, J.L.; Lei, Ming; Stekel, A.; Bell, T.M.; Leisure, R. G.; Sham, L.J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department