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Sulfide ceramics in molten-salt electrolyte batteries

Description: Sulfide ceramics are finding application in the manufacture of advanced batteries with molten salt electrolyte. Use of these ceramics as a peripheral seal component has permitted development of bipolar Li/FeS{sub 2} batteries. This bipolar battery has a molten lithium halide electrolyte and operates at 400 to 450C. Initial development and physical properties evaluations indicate the ability to form metal/ceramic bonded seal (13-cm ID) components for use in high-temperature corrosive environments. These sealants are generally CaAl{sub 2}S{sub 4}-based ceramics. Structural ceramics (composites with oxide or nitride fillers), highly wetting sealant formulations, and protective coatings are also being developed. Sulfide ceramics show great promise because of their relatively low melting point, high-temperature viscous flow, chemical stability, high-strength bonding, and tailored coefficients of thermal expansion. Our methodology of generating laminated metal/ceramic pellets (e.g., molybdenum/sulfide ceramic/molybdenum) with which to optimize materials formulation and seal processing is described.
Date: June 1, 1995
Creator: Kaun, T.D.; Hash, M.C. & Simon, D.R.
Partner: UNT Libraries Government Documents Department

Synthesis of Cyclic Aza-Ether Compounds and Studies of Their Use as Anion Receptors in Non-Aqueous Lithium Halide Salt Solutions

Description: A series of new anion receptors, based on cyclic aza-ether compounds, have been synthesized. In all of these cyclic aza-ether compounds, the electron-withdrawing group CF{sub 3}SO{sub 2} was attached to each of the nitrogen atoms. When used as additives, all of them can significantly increase the ionic conductivity of lithium halide salts in THF solutions. This is due to the complexation between these compounds and halide anions. Ionic conductivity studies show that the complexation behavior is related to both the ring structure of the cyclic compounds and the characteristics of the halide anions. X-ray diffraction data show that the diffraction patterns of the complex crystals are different from the pure cyclic aza-ether compounds. New Bragg peaks representing a large d-spacing ({approx}15 {angstrom}) are observed for the complex crystals which provides a clear evidence for complexation.
Date: November 1, 1999
Creator: Lee, H. S.; Sun, X.; Yang, X. Q.; McBreen, J.; Callahan, J. H. & Choi, L. S.
Partner: UNT Libraries Government Documents Department

28-nm laser damage testing of LIF

Description: We have tested several samples of LIF, both single crystal and press forged, for damage resistance to 10-ns 248-nm pulses at 35 pps. The damage thresholds - the highest levels at which no damage could be produced - ranged from 4 to 6 J/cm/sup 2/ although some test sites survived irradiation at approx. 30 J/cm/sup 2/. We observed that bulk damage is the primary failure mechanism in single crystal and press forged samples and that both types exhibit the same resistance to laser damage.
Date: January 1, 1981
Creator: Foltyn, S.R. & Newman, B.E.
Partner: UNT Libraries Government Documents Department

Measurement of water diffusivity in aqueous lithium bromide solution

Description: The bulb apparatus developed was found to produce reliable data for measuring diffusivity for short duration. Diffusivity of water in aq. LiBr solution was found to increase from 13.2[times]10[sup [minus]10] to 16.7[times]10[sup [minus]10]m[sup 2]/s for concentration change from 0.5 to 4M and then decrease to a steady value of [approximately]6.5[times]10[sup [minus]10]m[sup 2]/s from 8 to 11 M.
Date: January 1, 1993
Creator: Potnis, S.V.; Lenz, T.G. & Dunlop, E.H.
Partner: UNT Libraries Government Documents Department

Emission spectra of sensitized and unsensitized LiF; TLD-100

Description: It was found in a study of the emission spectra of LiF powders, the glow curve shape appears to be independent of wave length. Data indicate that any recombination centers created by radiation could not have an optical transition significantly different from that of the recombination center originally present. (FS)
Date: January 1, 1965
Creator: Pearson, D. & Cameron, J.R.
Partner: UNT Libraries Government Documents Department

Acquisition of powder diffraction data with synchrotron radiation

Description: During the past year, a dedicated triple-axis powder diffractometer has been in routine operation at the Brookhaven National Synchrotron Light Source as a user-oriented facility. The diffractometer is designed to allow easy interchange between energy-dispersive and monochromatic beam experiments. In the latter mode of operation, high resolution data have been collected for a variety of samples with the use of the crystal-analyzer technique, and in several cases these data sets have been used successfully for structure solution and Rietveld refinement. Several aspects of data acquisition at a synchrotron beam-line are described, and some of the different types of scattering geometry which have been used are discussed. Simple expressions are given for the instrumental resolution function expressed as the angular variation of peak widths for each of these. The peak shapes observed for a reference sample of Si on the present triple-axis instrument are well-described by the convolution of Gaussian and Lorentzian functions, and the angular dependence of the Gaussian component is in excellent agreement with the corresponding calculated instrumental function. One of the most important considerations for each type of experiment is the necessary compromise between intensity and resolution over a wide range of scattering angles, and some of the available options will be discussed. In particular, the use of Ge(440) and LiF(400) analyzer crystals gives a focussing minimum at relatively high angles (2 THETA approx. = 50/sup 0/ at 1.54A), a highly desirable feature for Rietveld analysis of complex structures. Absolute intensities from reference samples of Si and CeO/sub 2/ are calculated for these and several other scattering configurations involving both flat-plate and capillary geometry to illustrate this compromise. 26 refs., 3 figs., 3 tabs.
Date: January 1, 1987
Creator: Cox, D.E.; Toby, B.H. & Eddy, M.M.
Partner: UNT Libraries Government Documents Department

Experimental studies of photon-surface interaction dynamics in the alkali halides

Description: We describe recent measurements which have provided, in unprecedented detail, insights into the electronic mechanisms through which energy carried into a material by photon irradiation is absorbed, localized and rechanneled to produce desorption, surface modification, erosion and damage. The specific object of these studies has been desorption induced by electronic transition in alkali halide crystals, with particular emphasis on the dynamics of changes in the surface and near-surface regions. In our experiments, the irradiating ultraviolet photons are provided by a synchrotron storage ring, and the dynamical information about desorption products is obtained from optical measurements of the quantum states, yields and velocity distributions of neutral ground-state and excited-state atoms ejected from the surface of the irradiating material. These studies have shown that the dominant exit channels in photon-induced particle emission are those producing ground-state and excited-state neutral atoms. Using dynamical information about these desorbing neutral species, obtained, for example, by laser-induced fluorescence and laser Doppler spectroscopy, we are generating an increasingly comprehensive picture of the dynamics of electronic energy flow into and out of pure crystalline surfaces in these prototypical dielectrics. We are also beginning to be able to relate desorption dynamics to specific materials properties, and to discriminate between pure surface and near-surface effects in these materials. Applications of these techniques to the problem of photon-induced surface damage and to analysis of surface dynamics in dielectric materials are discussed, and the relationships between these nearly ideal model materials and the non-crystalline, covalently bonded materials more typical of real optical elements are pointed out. 19 refs., 13 figs.
Date: January 1, 1986
Creator: Haglund, R.F. Jr. & Tolk, N.H.
Partner: UNT Libraries Government Documents Department

Beta dosimetry using pulsed laser heating of TLD materials

Description: Use of a pulsed CO/sub 2/ laser to heat the surface of hot-pressed LiF chips has been investigated. The thermoluminescent traps in the first 10 to 20 ..mu..m of depth may be read out with good efficiency, which will allow entrance dose and exit dose to be determined using a standard chip. These dose data can be used to calculate beta dose and gamma dose separately. Readout speed is estimated to be a few milliseconds per chip.
Date: January 1, 1983
Creator: Quam, W.
Partner: UNT Libraries Government Documents Department

Planar channeling radiation from relativistic positrons and electrons in LiF

Description: Channeling radiation has been measured for planar-channeled 54- and 83-MeV positrons and 17-, 31-, and 54-MeV electrons in the ionic crystal LiF. The results are shown to be in reasonable, but not perfect, agreement with the results of many-beam calculations based upon a model of the crystal as an array of isolated Li/sup +/ and F/sup -/ ions.
Date: July 1, 1983
Creator: Berman, B.L.; Datz, S.; Fearick, R.W.; Swent, R.L.; Pantell, R.H.; Park, H. et al.
Partner: UNT Libraries Government Documents Department

Press forging and optical properties of lithium fluoride

Description: Lithium fluoride is an important candidate material for windows on high-power, short-pulse ultraviolet and visible lasers. Lithium fluoride crystals have been press forged in one step over the temperature range 300 to 600/sup 0/c to obtain fine-grained polycrystalline material with improved mechanical properties. The deformation that can be given to a lithium fluoride crystal during forging is limited by the formation of internal cloudiness (veiling) with the deformation limit increasing with increasing forging temperature from about 40% at 400/sup 0/C to 65% at 600/sup 0/C. To suppress veiling, lithium fluoride crystals were forged in two steps over the temperature range 300 to 600/sup 0/C, to total deformations of 69-76%, with intermediate annealing at 700/sup 0/C. This technique yields a material which has lower scattering with more homogeneous microstructure than that obtained in one-step forging. The results of characterization of various optical and mechanical properties of single-crystal and forged lithium fluoride, including scattering, optical homogeneity, residual absorption, damage thresholds, environmental stability, and thresholds for microyield are described.
Date: January 1, 1979
Creator: Ready, J.F. & Vora, H.
Partner: UNT Libraries Government Documents Department

Open cycle lithium chloride cooling system. Final report, March 1, 1982-May 28, 1983

Description: A lithium chloride open cycle absorption chiller has been designed, built and tested. Solution reconcentration takes place in a small counter-current packed column supplied with solar heated air. Removal of non-condensable gases that enter the chiller dissolved in the strong solution and the make-up refrigerant streams is accomplished by a liquid-jet ejector and a small vacuum pump. Cooling capacities approaching 1.4 tons and COP levels of 0.58 have been achieved at non-optimum operating conditions. Test results from preliminary system operation suggest that mass transfer processes in both the packed column reconcentrator and the absorber are controlled by concentration gradients in the lithium chloride solution. Liquid phase controlled mass transfer dictates an operating strategy different from the previously assumed gas phase controlled process to obtain maximum rates of evaporation in the packed column. Determination of optimal operating conditions leading to decreased electrical power consumption and improved cooling capacity and coefficient of performance will require further analysis and testing.
Date: May 1, 1983
Creator: Lenz, T. G.; Loef, G. O.G.; Iyer, R. & Wenger, J.
Partner: UNT Libraries Government Documents Department

Characteristics and development report for the MC3714 thermal battery

Description: This report describes the design intent, design considerations, system use, development, product characteristics, and early production history of the MC3714 Thermal Battery. This battery has a required operating life of 146 s above 24.0 V with a constant current load of 0.5 A. It is activated when the MC3830 Actuator initiates the WW42C1 Percussion Primer in the battery. The MC3714 employs the Li(Si)/LiCl-CCl/lithiated FeS{sub 2} electrochemical system. The battery is a hermetically sealed right-circular cylinder with an antirotation ring brazed to the base of the cylinder. The battery is 50 mm long and 38.1 mm in diameter. The mass of the battery is 165 g. The battery was designed and developed to provide the power for the W82 JTA Telemetry System. 8 refs., 12 figs., 11 tabs.
Date: August 1, 1990
Creator: Scharrer, G.L. & Lasky, F.P.
Partner: UNT Libraries Government Documents Department

Personnel dose equivalent monitoring at SLAC using lithium-fluoride TLD's (thermoluminescent dosimeters)

Description: TLD's replaced film badges in the early 1970's for all dose equivalent monitoring, both neutron and photon, and for all locations at SLAC. The photon TLD's, composed of Li-7 loaded teflon discs, are calibrated using conventional gamma-ray sources; i.e., Co-60, Cs-137, etc. For these TLD's a nominal value of 1 nC/mrem is used, and is independent of source energy for 100 keV to 3 MeV. Since measured dose equivalents at SLAC are only a small fraction of the allowable levels, it was not deemed necessary to develop neutron dosimeters which would measure dose equivalent accurately for all possible neutron spectra. Today, wallet TLD's, composed of pairs of Li-7 and Li-6 discs, are used, with the Li-6 measuring only thermal neutrons; i.e., they aren't moderated in any way to make them sensitive to neutrons with energies greater than thermal. The assumption is made that there is a correlation between thermal neutron fluences and fast neutron fluences around the research area where almost all neutron doses (exclusive of sealed sources) are received. The calibration factor for these Li-6 TLD's is 1 nC/mrem of fast neutrons. The method of determining the validity of this calibration is the subject of this note. 4 refs., 9 figs., 1 tab.
Date: March 1, 1987
Creator: Jenkins, T.M. & Busick, D.D.
Partner: UNT Libraries Government Documents Department

Engineering design construction and testing of a salt-water absorption unit optimized for use with a solar collector heat source

Description: The development of a 3 ton direct evaporatively cooled LiBr chiller and the construction of three operable field test units suitable for use with flat plate collectors is reported. Compared to conventional LiBr chillers using shell and tube heat exchangers and a separate cooling tower this approach aims to reduce first cost, installation cost and parasitic power. The unit is packaged into a size approximately 94 cm square and 2 meters tall. It produces 7.2/sup 0/C (45F) chilled water with a .72 COP when fired with 89.4/sup 0/C (193F) hot water while rejecting heat to 25.6/sup 0/C (78F) wb ambient air. Power to operate the condenser fan, solution pump and surface wetting pump is 450 watts. This unit deals with water freezing by making the sump and wetting pump freeze resistant so that seasonal draining is not required. Low heat flux through the wetted surfaces yields performance insensitivity to the accumulation of scale.
Date: March 1, 1979
Creator: Ferguson, T. & Merrick, R.H.
Partner: UNT Libraries Government Documents Department

A positronium beam and positronium reflection from LiF(100)

Description: We report results obtained from a variable energy monoenergetic beam of positronium (Ps). Ps was formed by a charge transfer reaction of positrons colliding with Ar gas atoms in a ''gas cell'' with an efficiency of about 3 /times/ 10/sup /minus/4/. The beam was used to measure the fraction, R, of specularly reflected ortho-Ps from LiF(100). We found R to peak at about 30% for 7 eV Ps at a specular scattering angle of 50/degree/ to 60/degree/. At higher energies R drops sharply to values around 0.5% near 60 eV Ps.
Date: January 1, 1988
Creator: Weber, M.; Tang, S.; Berko, S.; Brown, B.L.; Canter, K.F.; Lynn, K.G. et al.
Partner: UNT Libraries Government Documents Department

Analysis of an improved solar-powered cooling system utilizing open-cycle absorbent regeneration

Description: A solar-powered cooling system which promises high system C.O.P.'s and low collector costs is analyzed. It consists of a desiccant and an absorption cooling system operating in series to both dry and cool the air. A common solution of lithium chloride is used as the absorbant. The lithium chloride solution is regenerated by evaporating the excess water to the atmosphere in an ''open'' collector. This collector consists merely of a blackened flat surface. The weak solution of lithium chloride is introduced at the top of the collector and then flows by gravity over the entire collector surface where it is subsequently heated and dried. The daily performance of this combined system is compared by computer simulation to that of either an absorption or desiccant system alone using actual weather data for five typical U.S. cities. The performance improvement of the combined system ranged from 25% to 95%, the greatest improvement being for humid, windy conditions.
Date: January 1, 1978
Creator: Collier, R.K.
Partner: UNT Libraries Government Documents Department

Materials and mechanics of rate effects in brittle fracture. Progress report, October 1979-October 1980

Description: Energy balance methods have been used to find the crack driving force in elastic fractures. The fracture toughness of cracked steel bars have been measured using these techniques. Crack tip dislocations have been shown to protect the crack tip by having a stress intensity value that is opposite in sign from the applied stress intensity value. Thus, crack tip dislocation plasticity shields the crack from the external stress intensity factor. In the fatigue of LiF single crystals a relationship between monotonic and fatigue hardening responses has been established using a statistical model for fatigue deformation.
Date: January 1, 1980
Creator: Burns, S.J.
Partner: UNT Libraries Government Documents Department

Soft x-ray emission spectra of lithium fluoride excited by synchrotron radiation

Description: A core excited Li atom is perhaps the simplest cation defect that can be introduced into LiF. It frequently binds an electron in an electronic state, whose properties dominate both the soft x-ray absorption and soft x-ray emission properties of LiF. This phenomena was examined using a new, very high efficiency, emission spectrometer. Exciton and valence band peaks were observed which decay with time and are replaced by a metallic Li peak at 54 eV.
Date: January 1, 1986
Creator: Tsang, K.L.; Zhang, C.H.; Callcott, T.A.; Arakawa, E.T. & Ederer, D.L.
Partner: UNT Libraries Government Documents Department

Positronium reflection and positronium beams

Description: We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 {plus minus} 0.15){Angstrom} for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbents on it. Two methods for producing Ps beams are described. 29 refs., 11 figs.
Date: January 1, 1989
Creator: Weber, M.; Tang, S.; Khatri, R.; Roellig, L.O.; Viescas, A.J. (City Coll., New York, NY (USA)); Berko, S. et al.
Partner: UNT Libraries Government Documents Department

Incorporation of Monte Carlo electron interface studies into photon general cavity theory

Description: Electron Monte Carlo calculations using CYLTRAN and a new PHSECE (Photon Produced Secondary Electrons) technique were carried out to estimate electron fluences and energy deposition profiles near LiF/Al and LiF/Pb material interfaces undergoing Co-60 gamma irradiation. Several interesting and new features emerge: (1) Although the build-up of the secondary electron fluences at the interfaces of the irradiated media is approximately exponential, the value of the electron mass fluence build-up coefficient, ..beta.. is not equal to the electron mass fluence attenuation coefficient, ..beta../sub A/. (2) The attenuation of the gamma-generated electron fluences at the cavity-medium interfaces, ..beta../sub A/, is strongly dependent on the Z of the adjacent material, and (3) for LiF/Pb there is a significant intrusion energy deposition mode arising from side-scattering in the wall (Pb) material. These new features of interface dosimetry (at least (1) and (2)) are incorporated into the photon general cavity expressions of Burlin-Horowitz and Kearsley and compared with experimental data. 9 references, 4 figures.
Date: January 1, 1985
Creator: Horowitz, Y.S.; Moscovitch, M.; Hsu, H.; Mack, J.M. & Kearsley, E.
Partner: UNT Libraries Government Documents Department

Channeling-radiation measurements at Lawrence Livermore National Laboratory. Revision 1

Description: In the last few years, the amount and quality of channeling-radiation data have increased enormously, owing largely to much improved experimental capabilities. Current results included improved interplanar potentials for diamond, the description of the effect of platelets in diamond as an average thermal vibration, an improved determination of the Debye temperature of silicon, an improved determination of the thermal-vibration amplitude of LiD, and the demonstration that LiF crystal structures can survive intense electron bombardment. 40 references, 8 figures.
Date: October 1, 1984
Creator: Berman, B.L.; Dahling, B.A.; Datz, S.; Kephart, J.O.; Klein, R.K.; Pantell, R.H. et al.
Partner: UNT Libraries Government Documents Department

Scattering of phonons by dislocations

Description: By 1950, an explicit effort had been launched to use lattice thermal conductivity measurements in the investigation of defect structures in solids. This technique has been highly successful, especially when combined with the measurements of other properties such as optical absorption. One exception has been the study of dislocations. Although dislocations have a profound effect on the phonon thermal conductivity, the mechanisms of the phonon-dislocation interaction are poorly understood. The most basic questions are still debated in the literature. It therefore is pointless to attempt a quantitative comparison between an extensive accumulation of experimental data on the one hand, and the numerous theoretical models on the other. Instead, this chapter will attempt to glean a few qualitative conclusions from the existing experimental data. These results will then be compared with two general models which incorporate, in a qualitative manner, most of the proposed theories of the phonon-dislocation interaction. Until very recently, measurement of thermal conductivity was the only means available to probe the interaction between phonons and defects at phonon frequencies above the standard ultrasonic range of approx. = 10/sup 9/ Hz. The introductory paragraphs provide a brief review of the thermal-conductivity technique and the problems which are encountered in practice. There is also a brief presentation of the theoretical models and the complications that may occur in more realistic situations.
Date: January 1, 1979
Creator: Anderson, A. C.
Partner: UNT Libraries Government Documents Department

Study of material properties using channeling radiation

Description: A possible application for channeling radiation is for investigating the properties of crystals in which the channeling occurs. In this paper we present some general considerations concerning channeling radiation as a measurement technique, and then we proceed to describe several specific examples.
Date: January 1, 1986
Creator: Pantell, R.H.; Kephart, J.O.; Klein, R.K.; Park, H.; Berman, B.L. & Datz, S.
Partner: UNT Libraries Government Documents Department

A positronium beam and positronium reflection from LiF

Description: A positronium (Ps) beam has been constructed by transmitting monoenergetic, low energy positrons through a gas cell containing either Ar or He which provide an electron to form positronium. The positrons were obtained by magnetically deflecting positrons in the straight section of the positron beamline into a beamline which contained the gas cell and a Ps detection chamber. The two beamlines provide the capability of switching from an experiment which uses positrons (a study of the angular correlation of annihilating radiation - ACAR) to one which uses Ps atoms without breaking vacuum, nor moving equipment. The authors report the characteristics of the two beams and state that very preliminary information has been obtained on the characteristics of the Ps beamline and on the reflection of Ps from a LiF crystal.
Date: January 1, 1987
Creator: Weber, M.; Berko, S.; Brown, B.L.; Canter, K.F.; Lynn, K.G.; Mills, A.P. Jr. et al.
Partner: UNT Libraries Government Documents Department