National Library of Energy BETA

Sample records for ra zr hf

  1. Ternary ceramic alloys of Zr-Ce-Hf oxides

    DOE Patents [OSTI]

    Becher, P.F.; Funkenbusch, E.F.

    1990-11-20

    A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

  2. Metal-Organic Frameworks Based on Previously Unknown Zr8/Hf Cubic...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Metal-Organic Frameworks Based on Previously Unknown Zr8Hf Cubic Clusters Previous Next List Dawei Feng, Hai-Long Jiang, Ying-Pin Chen, Zhi-Yuan Gu, Zhangwen Wei, and Hong-Cai...

  3. Ternary ceramic alloys of ZR-CE-HF oxides

    DOE Patents [OSTI]

    Becher, Paul F.; Funkenbusch, Eric F.

    1990-01-01

    A ternary ceramic alloy which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce.sub.x Hf.sub.y Zn.sub.1-x-y O.sub.2, is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites.

  4. Continuous production of granular or powder Ti, Zr and Hf or their alloy products

    DOE Patents [OSTI]

    White, Jack C.; Oden, Laurance L.

    1993-01-01

    A continuous process for producing a granular metal selected from the group consisting of Ti, Zr or Hf under conditions that provide orderly growth of the metal free of halide inclusions comprising: a) dissolving a reducing metal selected from the group consisting of Na, Mg, Li or K in their respective halide salts to produce a reducing molten salt stream; b) preparing a second molten salt stream containing the halide salt of Ti, Zr or Hf; c) mixing and reacting the two molten streams of steps a) and b) in a continuous stirred tank reactor; d) wherein steps a) through c) are conducted at a temperature range of from about 800.degree. C. to about 1100.degree. C. so that a weight percent of equilibrium solubility of the reducing metal in its respective halide salt varies from about 1.6 weight percent at about 900.degree. C. to about 14.4 weight percent at about 1062.degree. C.; and wherein a range of concentration of the halide salt of Ti, Zn or Hf in molten halides of Na, Mg, Li or K is from about 1 to about 5 times the concentration of Na, Mg, Li or K; e) placing the reacted molten stream from step c) in a solid-liquid separator to recover an impure granular metal product by decantation, centrifugation, or filtration; and f) removing residual halide salt impurity by vacuum evaporator or inert gas sweep at temperatures from about 850.degree. C. to 1000.degree. C. or cooling the impure granular metal product to ambient temperature and water leaching off the residual metal halide salt.

  5. Impact of cyclic plasma treatment on oxygen vacancy defects in TiN/HfZrO/SiON/Si gate stacks

    SciTech Connect (OSTI)

    Bhuyian, Md Nasir Uddin Misra, D.; Poddar, S.; Tapily, K.; Clark, R. D.; Consiglio, S.; Wajda, C. S.; Nakamura, G.; Leusink, G. J.

    2015-05-11

    This work evaluates the defects in HfZrO as a function of Zr addition into HfO{sub 2} and when the dielectric was subjected to a slot-plane-antenna (SPA) plasma treatment in a cyclic process to form TiN/HfZrO/SiON/Si gate stacks. The defect energy levels, estimated by temperature-dependent current-voltage measurements, suggest that Zr addition in HfO{sub 2} modifies the charge state of the oxygen vacancy formation, V{sup +}. The influence of electron affinity variation of Hf and Zr ions on the charged oxygen vacancy levels seems to have contributed to the increase in defect activation energy, E{sub a}, from 0.32 eV to 0.4 eV. The cyclic SPA plasma exposure further reduces the oxygen vacancy formation because of the film densification. When the dielectric was subjected to a constant voltage stress, the charge state oxygen vacancy formation changes to V{sup 2+} and improvement was eliminated. The trap assisted tunneling behavior, as observed by the stress induced leakage current characteristics, further supports the oxygen vacancy formation model.

  6. Hole Trapping at Surfaces of m?ZrO2 and m?HfO2 Nanocrystals

    SciTech Connect (OSTI)

    Wolf, Matthew J.; Mckenna, Keith P.; Shlyuger, Alexander L.

    2012-12-03

    We investigate hole trapping at the most prevalent facets of monoclinic zirconia (m-ZrO2) and hafnia (m-HfO2) nanocrystals using first-principles methods. The localization of holes at surface oxygen ions is more favorable than in the bulk crystal by up to ?1 eV. This is caused mainly by the reduction of the absolute value of the electrostatic potential at the surface ions with respect to the bulk and by the significant surface distortion caused by the hole localization. The mobility of holes at surfaces is much lower than that found in the bulk and is fairly isotropic. Unlike in cubic oxides, such as MgO and CaO, we do not find a significant driving force for preferential trapping of holes at steps on the m-ZrO2 surface. These fundamental results are relevant to mechanisms of water oxidation, photocatalysis, contact charging, and photodesorption.

  7. Electron-stimulated desorption from polished and vacuum fired 316LN stainless steel coated with Ti-Zr-Hf-V

    SciTech Connect (OSTI)

    Malyshev, Oleg B. Valizadeh, Reza; Hogan, Benjamin T.; Hannah, Adrian N.

    2014-11-01

    In this study, two identical 316LN stainless steel tubular samples, which had previously been polished and vacuum-fired and then used for the electron-stimulated desorption (ESD) experiments, were coated with Ti-Zr-Hf-V with different morphologies: columnar and dense. ESD measurement results after nonevaporable getter (NEG) activation to 150, 180, 250, and 350 °C indicated that the values for the ESD yields are significantly (2–20 times) lower than the data from our previous study with similar coatings on nonvacuum-fired samples. Based on these results, the lowest pressure and best long-term performance in particle accelerators will be achieved with a vacuum-fired vacuum chamber coated with dense Ti-Zr-Hf-V coating activated at 180 °C. This is likely due to the following facts: after NEG activation, the hydrogen concentration inside the NEG was lower than in the bulk stainless steel substrate; the NEG coating created a barrier for gas diffusion from the sample bulk to vacuum; the dense NEG coating performed better as a barrier than the columnar NEG coating.

  8. Orthorhombic-tetragonal phase coexistence and enhanced piezo-response at room temperature in Zr, Sn, and Hf modified BaTiO{sub 3}

    SciTech Connect (OSTI)

    Kalyani, Ajay Kumar; Brajesh, Kumar; Ranjan, Rajeev; Senyshyn, Anatoliy

    2014-06-23

    The effect of Zr, Hf, and Sn in BaTiO{sub 3} has been investigated at close composition intervals in the dilute concentration limit. Detailed structural analysis by x-ray and neutron powder diffraction revealed that merely 2 mol. % of Zr, Sn, and Hf stabilizes a coexistence of orthorhombic (Amm2) and tetragonal (P4mm) phases at room temperature. As a consequence, all the three systems show substantial enhancement in the longitudinal piezoelectric coefficient (d{sub 33}), with Sn modification exhibiting the highest value ∼425 pC/N.

  9. Hydrolysis of ZrCl4 and HfCl4: The Initial Steps in the High-Temperature Oxidation of Metal Chlorides to Produce ZrO2 and HfO2

    SciTech Connect (OSTI)

    Fang, Zongtang; Dixon, David A.

    2013-03-08

    The gas-phase hydrolysis of MCl4 (M = Zr, Hf) to produce the initial particles on the way to zirconia and hafnia nanoparticles has been studied with electronic structure theory. The potential energy surfaces, the themochemistry of the reaction species, and the reaction paths for the initial steps of MCl4 reacting with H2O have been calculated. The hydrolysis of MCl4 at higher temperatures begins with the formation of oxychlorohydroxides followed by the elimination of HCl instead of the direct production of MOCl2 and HCl or MO2 and HCl due to the substantial endothermicities associated with the formation of gas-phase MO2. The structural properties and heats of formation of the reactants and products are consistent with the available experimental results. A number of metal oxychlorides (oxychlorohydroxides) intermediate clusters have been studied to assess their role in the production of MO2 nanoparticles. The calculated clustering reaction energies of those intermediates are highly exothermic, so they could be readily formed in the hydrolysis process. These intermediate clusters can be formed exothermically from metal oxychlorohydroxides by the elimination of one HCl or H2O molecule. Our calculations show that the mechanisms leading to the formation of MO2 nanoparticles are complicated and are accompanied by the potential production of a wide range of intermediates, as found for the production of TiO2 particles from the high-temperature oxidation of TiCl4.

  10. Manipulation of electronic and magnetic properties of M{sub 2}C (M = Hf, Nb, Sc, Ta, Ti, V, Zr) monolayer by applying mechanical strains

    SciTech Connect (OSTI)

    Zhao, Shijun; Kang, Wei; Xue, Jianming

    2014-03-31

    Tuning the electronic and magnetic properties of a material through strain engineering is an effective strategy to enhance the performance of electronic and spintronic devices. In this paper, first-principles calculations based on density functional theory are carried out to investigate the electronic and magnetic properties of M{sub 2}C(M = Hf, Nb, Sc, Ta, Ti, V, Zr, known as MXenes) subjected to biaxial symmetric mechanical strains. At the strain-free state, all these MXenes exhibit no spontaneous magnetism except for Ti{sub 2}C and Zr{sub 2}C which show a magnetic moment of 1.92 and 1.25 μ{sub B}/unit, respectively. As the tensile strain increases, the magnetic moments of MXenes are greatly enhanced and a transition from nonmagnetism to ferromagnetism is observed for those nonmagnetic MXenes at zero strains. The most distinct transition is found in Hf{sub 2}C, in which the magnetic moment is elevated to 1.5 μ{sub B}/unit at a strain of 1.80%. We further show that the magnetic properties of Hf{sub 2}C are attributed to the band shift mainly composed of Hf(5d) states.

  11. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. II. Adsorption of tetrachlorides and oxydichlorides of Zr, Hf, and Rf on neutral and modified surfaces

    SciTech Connect (OSTI)

    Pershina, V.; Borschevsky, A.; Iliaš, M.; Türler, A.

    2014-08-14

    With the aim to interpret results of gas-phase chromatography experiments on volatility of group-4 tetrachlorides and oxychlorides including those of Rf, adsorption enthalpies of these species on neutral, and modified quartz surfaces were estimated on the basis of relativistic, two-component Density Functional Theory calculations of MCl{sub 4}, MOCl{sub 2}, MCl{sub 6}{sup −}, and MOCl{sub 4}{sup 2} with the use of adsorption models. Several mechanisms of adsorption were considered. In the case of physisorption of MCl{sub 4}, the trend in the adsorption energy in the group should be Zr > Hf > Rf, so that the volatility should change in the opposite direction. The latter trend complies with the one in the sublimation enthalpies, ΔH{sub sub}, of the Zr and Hf tetrachlorides, i.e., Zr < Hf. On the basis of a correlation between these quantities, ΔH{sub sub}(RfCl{sub 4}) was predicted as 104.2 kJ/mol. The energy of physisorption of MOCl{sub 2} on quartz should increase in the group, Zr < Hf < Rf, as defined by increasing dipole moments of these molecules along the series. In the case of adsorption of MCl{sub 4} on quartz by chemical forces, formation of the MOCl{sub 2} or MOCl{sub 4}{sup 2−} complexes on the surface can take place, so that the sequence in the adsorption energy should be Zr > Hf > Rf, as defined by the complex formation energies. In the case of adsorption of MCl{sub 4} on a chlorinated quartz surface, formation of the MCl{sub 6}{sup 2−} surface complexes can occur, so that the trend in the adsorption strength should be ZrHf < Rf. All the predicted sequences, showing a smooth change of the adsorption energy in the group, are in disagreement with the reversed trend Zr ≈ Rf < Hf, observed in the “one-atom-at-a-time” gas-phase chromatography experiments. Thus, currently no theoretical explanation can be found for the experimental observations.

  12. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. I. Electronic structures and properties of MCl{sub 4} and MOCl{sub 2} (M = Ti, Zr, Hf, and Rf)

    SciTech Connect (OSTI)

    Pershina, V.; Borschevsky, A.; Iliaš, M.

    2014-08-14

    Relativistic, infinite order exact two-component, density functional theory electronic structure calculations were performed for MCl{sub 4} and MOCl{sub 2} of group-4 elements Ti, Zr, Hf, and element 104, Rf, with the aim to predict their behaviour in gas-phase chromatography experiments. RfCl{sub 4} and RfOCl{sub 2} were shown to be less stable than their lighter homologs in the group, tetrachlorides and oxychlorides of Zr and Hf, respectively. The oxychlorides turned out to be stable as a bent structure, though the stabilization energy with respect to the flat one (C{sub 2v}) is very small. The trend in the formation of the tetrachlorides from the oxychlorides in group 4 is shown to be Zr < Hf < Rf, while the one in the formation of the oxychlorides from the chlorides is opposite. All the calculated properties are used to estimate adsorption energy of these species on various surfaces in order to interpret results of gas-phase chromatography experiments, as is shown in Paper II.

  13. Energy efficient microwave synthesis of mesoporous Ce0.5M0.5O2 (Ti, Zr, Hf) nanoparticles for low temperature CO oxidation in an ionic liquid – a comparative study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Alammar, Tarek; Chow, Ying -Kit; Mudring, Anja -Verena

    2014-11-19

    Ce0.5M0.5O2 (M = Ti, Zr, Hf) nanoparticles have been successfully synthesized by microwave irradiation in the ionic liquid [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide). The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2–adsorption measurements. XRD and Raman spectroscopy analyses confirmed the formation of solid solutions with cubic fluorite structure. The catalytic activities of the Ce0.5M0.5O2 (M = Ti, Zr, Hf) nanoparticles were investigated in the low-temperature oxidation of CO. Ce0.5Zr0.5O2 nanospheres exhibit the best performance (100% conversion at 350 °C), followed by Ce0.5Hf0.5O2more » (55% conversion at 360 °C) and Ce0.5Ti0.5O2 (11% conversion at 350 °C). Heating the as-prepared Ce0.5Zr0.5O2 to 600 °C for extended time leads to a decrease in surface area and, as expected decreased catalytic activity. Depending on the ionic liquid the obtained Ce0.5Zr0.5O2 exhibits different morphologies, varying from nano-spheres in [C4mim][Tf2N] and [P66614][Tf2N] (P66614 = trishexyltetradecylphosphonium) to sheet-like assemblies in [C3mimOH][Tf2N] (C3mimOH = 1-(3-hydroxypropyl)-3-methylimidazolium). As a result, the microwave synthesis superiority to other heating methods like sonochemical synthesis and conventional heating was proven by comparative experiments where the catalytic activity of Ce0.5Zr0.5O2 obtained by alternate methods such as conventional heating was found to be poorer than that of the microwave-synthesised material.« less

  14. First-principles studies of structural stabilities and enthalpies of formation of refractory intermetallics: TM and TM3 (T = Ti, Zr, Hf; M = Ru, Rh, Pd, Os, Ir, Pt)

    SciTech Connect (OSTI)

    Xing, Weiwei; Chen, X.; Li, Dianzhong; Li, Y. Y.; Fu, Chong Long; Meschel, S.

    2012-01-01

    Using first-principles local density functional approach, we have calculated the ground-state structural phase stabilities and enthalpies of formation of thirty-six binary transition-metal refractory TM and TM3 compounds formed by Group IV elements T (T = Ti, Zr, Hf) and platinum group elements M (M = Ru, Rh, Pd, Os, Ir, Pt) . We compared our results with the available experimental data and found good agreement between theory and experiment in both the trends of structural stabilities and the magnitudes of formation enthalpies. Moreover, based on our calculated results, an empirical relationship between cohesive energies ( E) and melting temperatures (Tm) was derived as Tm = 0.0292 E/kB (where kB is the Boltzmann constant) for both TM and TM3 compounds.

  15. Elastic properties of perovskite ATiO{sub 3} (A = Be, Mg, Ca, Sr, and Ba) and PbBO{sub 3} (B = Ti, Zr, and Hf): First principles calculations

    SciTech Connect (OSTI)

    Pandech, Narasak; Limpijumnong, Sukit; Sarasamak, Kanoknan

    2015-05-07

    The mechanical properties of perovskite oxides depend on two metal oxide lattices that are intercalated. This provides an opportunity for separate tuning of hardness, Poisson's ratio (transverse expansion in response to the compression), and shear strength. The elastic constants of series of perovskite oxides were studied by first principles approach. Both A-site and B-site cations were systematically varied in order to see their effects on the elastic parameters. To study the effects of A-site cations, we studied the elastic properties of perovskite ATiO{sub 3} for A being Be, Mg, Ca, Sr, or Ba, one at a time. Similarly, for B-site cations, we studied the elastic properties of PbBO{sub 3} for B being Ti, Zr, or Hf, one at a time. The density functional first principles calculations with local density approximation (LDA) and generalized gradient approximation (GGA) were employed. It is found that the maximum C{sub 11} elastic constant is achieved when the atomic size of the cations at A-site and B-site are comparable. We also found that C{sub 12} elastic constant is sensitive to B-site cations while C{sub 44} elastic constant is more sensitive to A-site cations. Details and explanations for such dependencies are discussed.

  16. Exploration of R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd2AlGe2 and Analysis of the U3Si2 and Zr3Al2 Structure Types

    SciTech Connect (OSTI)

    Sean William McWhorter

    2006-05-01

    In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} several new compounds were synthesized with different crystal structures, but similar structural features. In Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} can be thought of as being formed from two 3{sup 2}434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd{sub 2}MgGe{sub 2} and Gd{sub 2}InGe{sub 2} both possess the same 3{sup 2}434 nets of Gd atoms as Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, but these nets are connected differently, forming the Mo{sub 2}FeB{sub 2} crystal structure. A search of the literature revealed that compounds with the composition R{sub 2}XM{sub 2} (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo{sub 2}FeB{sub 2}, Zr{sub 3}Al{sub 2}, Mn{sub 2}AlB{sub 2} and W{sub 2}CoB{sub 2} crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd{sub 2}AlGe{sub 2} forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how electrons can be accounted for. A series of electronic structure calculations were performed on models with the U{sub 3}Si{sub 2} and Zr{sub 3}Al{sub 2} structures, using Zr and A1 as

  17. Energy efficient microwave synthesis of mesoporous Ce0.5M0.5O2 (Ti, Zr, Hf) nanoparticles for low temperature CO oxidation in an ionic liquid – a comparative study

    SciTech Connect (OSTI)

    Alammar, Tarek; Chow, Ying -Kit; Mudring, Anja -Verena

    2014-11-19

    Ce0.5M0.5O2 (M = Ti, Zr, Hf) nanoparticles have been successfully synthesized by microwave irradiation in the ionic liquid [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide). The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2–adsorption measurements. XRD and Raman spectroscopy analyses confirmed the formation of solid solutions with cubic fluorite structure. The catalytic activities of the Ce0.5M0.5O2 (M = Ti, Zr, Hf) nanoparticles were investigated in the low-temperature oxidation of CO. Ce0.5Zr0.5O2 nanospheres exhibit the best performance (100% conversion at 350 °C), followed by Ce0.5Hf0.5O2 (55% conversion at 360 °C) and Ce0.5Ti0.5O2 (11% conversion at 350 °C). Heating the as-prepared Ce0.5Zr0.5O2 to 600 °C for extended time leads to a decrease in surface area and, as expected decreased catalytic activity. Depending on the ionic liquid the obtained Ce0.5Zr0.5O2 exhibits different morphologies, varying from nano-spheres in [C4mim][Tf2N] and [P66614][Tf2N] (P66614 = trishexyltetradecylphosphonium) to sheet-like assemblies in [C3mimOH][Tf2N] (C3mimOH = 1-(3-hydroxypropyl)-3-methylimidazolium). As a result, the microwave synthesis superiority to other heating methods like sonochemical synthesis and conventional heating was proven by comparative experiments where the catalytic activity of Ce0.5Zr0.5O2 obtained by alternate methods such as conventional heating was found to

  18. Lanthanum pyrochlores and the effect of yttrium addition in the systems La{sub 2-x}Y{sub x}Zr{sub 2}O{sub 7} and La{sub 2-x}Y{sub x}Hf{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Whittle, Karl R. Cranswick, Lachlan M.D.; Redfern, Simon A.T.; Swainson, Ian P.; Lumpkin, Gregory R.

    2009-03-15

    The crystal structures of the compounds La{sub 2-x}Y{sub x}Zr{sub 2}O{sub 7} and La{sub 2-x}Y{sub x}Hf{sub 2}O{sub 7} with x=0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 have been studied using neutron powder diffraction and electron microscopy to determine the stability fields of the pyrochlore and fluorite solid solutions. The limits of pyrochlore stability in these solid solutions are found to be close to La{sub 0.8}Y{sub 1.2}Zr{sub 2}O{sub 7} and La{sub 0.4}Y{sub 1.6}Hf{sub 2}O{sub 7}, respectively. In both systems the unit cell parameter is found to vary linearly with Y content across those compositions where the pyrochlore phase is stable, as does the x-coordinate of the oxygen atoms on the 48f (x,3/8 ,3/8 ) sites. In both systems, linear extrapolations of the pyrochlore data suggest that the disordering is accompanied by a small decrease in the lattice parameter of approximately 0.4%. After the pyrochlore solid solution limit is reached, a sharp change is observed from x{approx}0.41 to 0.375 as the disordered defect fluorite structure is favoured. Electron diffraction patterns illustrate that some short-range order remains in the disordered defect fluorite phases. - Graphical abstract: Short-range ordering has been seen in the defect fluorites Y{sub 2}Zr{sub 2}O{sub 7} and Y{sub 2}Hf{sub 2}O{sub 7}, where they previously were thought to be entirely disordered. Evidence suggests the correlation length changes with composition, but is not commensurate with unit cell sizes.

  19. Microsoft Word - Ra-15

    Broader source: Energy.gov (indexed) [DOE]

    Grant Funding OAS-RA-10-15 August 2010 Additional Information Special Report on "Review of the Department of Energy's Plan for Obligating Remaining Recovery Act Contract and Grant ...

  20. Hf-irJ

    Office of Legacy Management (LM)

    Hf-irJ jnj,4 States Governmen Department of Energy Inemorandum DOTE: DAY o 1S5a . 7 EPY TO F . O 0 NE-24 SUJEC': Authorization for Remedial Action of Residential Vicinity ...

  1. Characterizing HfXZr1-XO2 by EXAFS: Relationship Between Bulk and Surface Composition, and Impact on Catalytic Selectivity for Alcohol Conversion

    SciTech Connect (OSTI)

    Jacobs, G.; Milling, M; Ji, Y; Patterson, P; Sparks, D; Davis, B

    2009-01-01

    A series of mixed Hf{sub X}Zr{sub 1-X}O{sub 2} oxide catalysts was prepared according to a recipe that yields the monoclinic structure. The samples were examined by EXAFS spectroscopy at the Zr K and Hf L{sub III} edges. A fitting model was used that simultaneously fits data from both edges, and makes use of an interdependent mixing parameter X mix to take into account substitution of the complementary atom in the nearest metal-metal shell. For XPS analysis, Scofield factors were applied to estimate the relative atomic surface concentrations of Zr and Hf. EXAFS results suggested that a solid bulk solution was formed over a wide range of X for Hf{sub X}Zr{sub 1-X}O{sub 2} binary oxides, and that the relative ratio was retained in the surface shell (i.e., including some subsurface layers by XPS) and the surface (e.g., by ISS). The increase in selectivity for the 1-alkene from dehydration of alcohols at high Zr content does not correlate smoothly with the tuned relative atomic concentration of Hf to Zr. The step change at high Zr content appears to be due to other indirect factors (e.g., surface defects, oxygen vacancies).

  2. Co.ra

    Office of Legacy Management (LM)

    Co.ra ARGONNEX4TIONALI$S'ATGRY 'i' : .: glbo South Caea!Avenue Argenne, IAuilm3- 6owJ . I.,? , m-m-769/ 5 April 1965 ,- Mr. K. 0. Wasson Coors Porcelain Cowany tie1 Elanen% Building Golden, Colorado Dear Mr. Wasson: '* -.c,. *.-':-- ~., _, ., Under seprate cover our RuXhasing Departmeat is requesting a quote for six fuel specimens. Except for composition, the specimens are to be identical to the pieces identified by requisition number 702881. The six specimens shall have the following

  3. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    McGuire, Michael A.; Rios, Orlando

    2015-02-05

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23 andmore » Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.« less

  4. Investigation of ?-ZrH1.66/?-Zr interface in Zr-based Cladding...

    Office of Scientific and Technical Information (OSTI)

    Cladding Materials with Aberration-Corrected STEM. Citation Details In-Document Search Title: Investigation of ?-ZrH1.66?-Zr interface in Zr-based Cladding Materials with ...

  5. Valence electronenergy-lossspectroscopystudyofZrSiO4 and ZrO2...

    Office of Scientific and Technical Information (OSTI)

    electronenergy-lossspectroscopystudyofZrSiO4 and ZrO2 ZrSiO4 (zircon) and m-ZrO2 (zirconia) are fundamental and industrially important materials.This work reports the detailed...

  6. Optical coatings for HF overtone laser

    SciTech Connect (OSTI)

    Xiong, S.; Zhang, Y.

    1996-12-31

    Optical components which highly reflect the hydrogen fluoride (HF) overtone wavelengths (near 1.3{micro}m) and transmit or absorb the HF fundamental wavelengths (2.6 to 3.1{micro}m) can be used to obtain high intensity 1.3{micro}m radiation with HF chemical laser technology. This paper describes the development of the HF overtone laser resonator mirrors. Also presented are the designs of the coatings for laser resonator and the optical performance results for the coatings which includes separated coatings that are highly reflected in 1.3--1.4{micro}m wavelengths and highly transmitted or low reflected in 2.6--3.1{micro}m wavelengths and the double band antireflection coating for 1.3--1.4{micro}m and 2.6--3.1{micro}m.

  7. On the road to HF mitigation

    SciTech Connect (OSTI)

    VanZele, R.L.; Diener, R. )

    1990-06-01

    The hazards of hydrogen fluoride (HF) have long been recognized and industry performance reflects sound operating practices. However, full-scale industry-sponsored HF release test conducted at the U.S. Department of Energy (DOE) test site in 1986 caused concern in view of HF's toxicity. Ambient impacts were greater than anticipated. And diking, a primary mitigation technique, proved ineffective for releases of pressurized superheated HF. In partial response to these new technical data, an ad-hoc three-component Industry Cooperative Hydrogen Fluoride Mitigation Assessment Program (ICHMAP) was begun in late 1987 to study and test techniques for mitigating accidental releases of HF and alkylation unit acid (AUA) and to enhance capabilities to estimate ambient impacts from such releases. AUA is a mixture of HF and hydrocarbons. The program's mitigation components have recently been completed while work on the impact assessment component is nearing completion. This article describes the program and summarizes the objective, scope of work, structure, and conclusions from the program's two mitigation components. In addition, the objectives and scope of work of the impact assessment components are described.

  8. Removal of uranium from aqueous HF solutions

    DOE Patents [OSTI]

    Pulley, Howard; Seltzer, Steven F.

    1980-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

  9. Rapid Method for Ra-226 and Ra-228 in Water Samples

    SciTech Connect (OSTI)

    Maxwell, Sherrod, L. III

    2006-02-10

    The measurement of radium isotopes in natural waters is important for oceanographic studies and for public health reasons. Ra-226 (1620 year half-life) is one of the most toxic of the long-lived alpha emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The analysis of radium-226 and radium-228 in natural waters can be tedious and time-consuming. Different sample preparation methods are often required to prepare Ra-226 and Ra-228 for separate analyses. A rapid method has been developed at the Savannah River Environmental Laboratory that effectively separates both Ra-226 and Ra-228 (via Ac-228) for assay. This method uses MnO{sub 2} Resin from Eichrom Technologies (Darien, IL, USA) to preconcentrate Ra-226 and Ra-228 rapidly from water samples, along with Ba-133 tracer. DGA Resin{reg_sign} (Eichrom) and Ln-Resin{reg_sign} (Eichrom) are employed in tandem to prepare Ra-226 for assay by alpha spectrometry and to determine Ra-228 via the measurement of Ac-228 by gas proportional counting. After preconcentration, the manganese dioxide is dissolved from the resin and passed through stacked Ln-Resin-DGA Resin cartridges that remove uranium and thorium interferences and retain Ac-228 on DGA Resin. The eluate that passed through this column is evaporated, redissolved in a lower acidity and passed through Ln-Resin again to further remove interferences before performing a barium sulfate microprecipitation. The Ac-228 is stripped from the resin, collected using cerium fluoride microprecipitation and counted by gas proportional counting. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  10. Numerical prediction of the thermodynamic properties of ternary Al-Ni-Hf alloys

    SciTech Connect (OSTI)

    Romanowska, Jolanta; Kotowski, S?awomir; Zagula-Yavorska, Maryana

    2014-10-06

    Thermodynamic properties of ternary Al-Hf-Ni system, such as {sup ex}G, ?{sub Al}, ?{sub Ni} and ?{sub Zr} at 1373K were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting {sup ex}G values was regarded as the calculation of excess Gibbs energy values inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of {sup ex}G on all legs of the triangle are known. {sup ex}G and L{sub ijk} ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism are calculated numerically using Wolfram Mathematica 9 software.

  11. Corrosion of high Ni-Cr alloys and Type 304L stainless steel in HNO/sub 3/-HF

    SciTech Connect (OSTI)

    Ondrejcin, R.S.; McLaughlin, B.D.

    1980-04-01

    Nineteen alloys were evaluated as possible materials of construction for steam heating coils, the dissolver vessel, and the off-gas system of proposed facilities to process thorium and uranium fuels. Commercially available alloys were found that are satisfactory for all applications. With thorium fuel, which requires HNO/sub 3/-HF for dissolution, the best alloy for service at 130/sup 0/C when complexing agents for fluoride are used is Inconel 690; with no complexing agents at 130/sup 0/C, Inconel 671 is best. At 95/sup 0/C, six other alloys tested would be adequate: Haynes 25, Ferralium, Inconel 625, Type 304L stainless steel, Incoloy 825, and Haynes 20 (in order of decreasing preference); based on composition, six untested alloys would also be adequate. The ions most effective in reducing fluoride corrosion were the complexing agents Zr/sup 4 +/ and Th/sup 4 +/; Al/sup 3 +/ was less effective. With uranium fuel, modestly priced Type 304L stainless steel is adequate. Corrosion will be most severe in HNO/sub 3/-HF used occasionally for flushing and in solutions of HNO/sub 3/ and corrosion products (ferric and dichromate ions). HF corrosion can be minimized by complexing the fluoride ion and by passivation of the steel with strong nitric acid. Corrosion caused by corrosion products can be minimized by operating at lower temperatures.

  12. 1800 Engineered Safety Work Planning and Controls and HF Delivery...

    Office of Scientific and Technical Information (OSTI)

    Conference: 1800 Engineered Safety Work Planning and Controls and HF Delivery System. ... Country of Publication: United States Language: English Word Cloud More Like This Full ...

  13. PROJECT PROFILE: Ra Power Management, Inc. (Incubator 10) | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Ra Power Management, Inc. (Incubator 10) PROJECT PROFILE: Ra Power Management, Inc. (Incubator 10) Project Title: RPM Asset Management Platform (AMP) Funding Opportunity: SunShot Technology to Market (Incubator 10) SunShot Subprogram: Technology to Market Location: Oakland, CA Amount Awarded: $500,000 Awardee Cost Share: $125,000 Project Investigator: Aaron Iverson Ra Power Management, Inc. (RPM) is developing a cloud-based software platform that manages the financial and operational

  14. Attendees- December 2014 P&RA Technical Exchange Meeting

    Office of Energy Efficiency and Renewable Energy (EERE)

    Attendees to the Performance & Risk Assessment Community of Practice (P&RA) Technical Exchange Meeting held in Las Vegas, Nevada on December 11 & 12, 2014.

  15. Ra Solar Systems Solutions SL | Open Energy Information

    Open Energy Info (EERE)

    Ra Solar Systems & Solutions SL Place: Madrid, Spain Zip: 28033 Sector: Solar Product: Spanish project developer and finance arranger for large-scale solar farms; also acts as...

  16. On the RA research reactor fuel management problems

    SciTech Connect (OSTI)

    Matausek, M.V.; Marinkovic, N.

    1997-12-01

    After 25 yr of operation, the Soviet-origin 6.5-MW heavy water RA research reactor was shut down in 1984. Basic facts about RA reactor operation, aging, reconstruction, and spent-fuel disposal have been presented and discussed in earlier papers. The following paragraphs present recent activities and results related to important fuel management problems.

  17. MicroPlanet Technology Corp formerly HF Capital Corp | Open Energy...

    Open Energy Info (EERE)

    Technology Corp formerly HF Capital Corp Jump to: navigation, search Name: MicroPlanet Technology Corp (formerly HF Capital Corp) Place: Seattle, Washington Zip: 98104 Sector:...

  18. Rainfall Manipulation Plot Study (RaMPS)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Blair, John [Kansas State University; Fay, Phillip [USDA-ARS; Knapp, Alan [Colorado State University; Collins, Scott [University of New Mexico; Smith, Melinda [Yale University

    Rainfall Manipulation Plots facility (RaMPs) is a unique experimental infrastructure that allows us to manipulate precipitation events and temperature, and assess population community, and ecosystem responses in native grassland. This facility allows us to manipulate the amount and timing of individual precipitation events in replicated field plots at the Konza Prairie Long-Term Ecological Research (LTER) site. Questions we are addressing include: • What is the relative importance of more extreme precipitation patterns (increased climatic variability) vs. increased temperatures (increased climatic mean) with regard to their impact on grassland ecosystem structure and function? Both projected climate change factors are predicted to decrease soil water availability, but the mechanisms by which this resource depletion occurs differ. • Will altered precipitation patterns, increased temperatures and their interaction increase opportunities for invasion by exotic species? • Will long-term (6-10 yr) trajectories of community and ecosystem change in response to more extreme precipitation patterns continue at the same rate as initial responses from years 1-6? Or will non-linear change occur as potential ecological thresholds are crossed? And will increased temperatures accelerate these responses? Data sets are available as ASCII files, in Excel spreadsheets, and in SAS format. (Taken from http://www.konza.ksu.edu/ramps/backgrnd.html

  19. Performance & Risk Assessment Community of Practice (P&RA CoP...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Performance & Risk Assessment Community of Practice (P&RA CoP) Performance & Risk Assessment Community of Practice (P&RA CoP) P&RA CoP's Technical Exchange Meeting held on December ...

  20. Synthesis and characterization of lanthanum phosphate nanoparticles as carriers for 223Ra and 225Ra for targeted alpha therapy

    SciTech Connect (OSTI)

    Rojas Marin, Jessika V; Woodward, Jonathan; Chen, Nan; Rondinone, Adam Justin; Castano, Carlos H; Mirzadeh, Saed

    2015-01-01

    Introduction. Targeted alpha therapy (TAT) has the potential for killing specific tumor cells with minimum collateral damage to surrounding healthy tissue. Radionuclides such as 223Ra, 225Ra, and 225Ac are of special interest for radiotherapeutic applications as they emit multiple -particles during their decay. Utilizing appropriate carriers capable of retaining both the parent radioisotope as well as daughter products is important for the effective delivery of the radioisotope to the tumor site while mitigating global in vivo radiotoxicity. Methods. In this work, core and core+2 shells (NPs with 2 additional layers of cold LaPO4 deposited on the core surfaces) LaPO4 nanoparticles (NPs) were synthesized containing either 223Ra or 225Ra/225Ac and the retention of the parents and daughters within the NPs in vitro was investigated. Results. The NPs crystallized in rhabdophane phase with mean diameters of 3.4 and 6.3 nm for core and core+2 shells, respectively. The core LaPO 4 NPs retained up to 88% of 223Ra over 35 days. However, in the core+2 shell NPs, the retention of 223Ra and its daughter, 211Pb, was improved to > 99.9% over 27 days. Additionally, the retention of 225Ra/225Ac parents was > 99.98% and ~80% for the 221Fr and 213Bi daughters over 35 days for the core+2 shell NPs. Conclusions. These results suggest that LaPO4 NPs are potentially effective carriers of radium isotopes.

  1. Improved Growth of High-Temperature Superconductors with HF Pressure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Control - Energy Innovation Portal Electricity Transmission Electricity Transmission Find More Like This Return to Search Improved Growth of High-Temperature Superconductors with HF Pressure Control Brookhaven National Laboratory Contact BNL About This Technology Publications: PDF Document Publication A new method of HF control for synthesizing YBCO using the BaF2 ex situ process (83 KB) Graphical representation of the removal of hydrogen fluoride gas by the absorber during growth of

  2. The Advanced Research Projects, OAS-RA-11-11

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Research Projects Agency - Energy OAS-RA-11-11 August 2011 Department of Energy Washington, DC 20585 August 22, 2011 MEMORANDUM FOR THE DIRECTOR, ADVANCED RESEARCH PROJECTS AGENCY ...

  3. Rapid determination of 226Ra in emergency urine samples

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed.more » The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.« less

  4. Synthesis and characterization of lanthanum phosphate nanoparticles as carriers for 223Ra and 225Ra for targeted alpha therapy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rojas, J. V.; Woodward, J. D.; Chen, N.; Rondinone, A. J.; Castano, C. H.; Mirzadeh, S.

    2015-03-19

    Targeted alpha therapy (TAT) has the potential for killing specific tumor cells with minimum collateral damage to surrounding healthy tissue. Radionuclides such as 223Ra, 225Ra, and 225Ac are of special interest for radiotherapeutic applications as they emit multiple -particles during their decay. Utilizing appropriate carriers capable of retaining both the parent radioisotope as well as daughter products is important for the effective delivery of the radioisotope to the tumor site while mitigating global in vivo radiotoxicity. Methods. In this work, core and core+2 shells (NPs with 2 additional layers of cold LaPO4 deposited on the core surfaces) LaPO4 nanoparticles (NPs)more » were synthesized containing either 223Ra or 225Ra/225Ac and the retention of the parents and daughters within the NPs in vitro was investigated. Results. The NPs crystallized in rhabdophane phase with mean diameters of 3.4 and 6.3 nm for core and core+2 shells, respectively. The core LaPO 4 NPs retained up to 88% of 223Ra over 35 days. However, in the core+2 shell NPs, the retention of 223Ra and its daughter, 211Pb, was improved to > 99.9% over 27 days. Additionally, the retention of 225Ra/225Ac parents was > 99.98% and ~80% for the 221Fr and 213Bi daughters over 35 days for the core+2 shell NPs. Conclusions. These results suggest that LaPO4 NPs are potentially effective carriers of radium isotopes.« less

  5. (U,Zr)N alloy having enhanced thermal stability

    DOE Patents [OSTI]

    Potter, Ralph A.; Scott, James L.

    1977-01-01

    A nitrided alloy of uranium and zirconium is provided which consists of a single-phase UN structure containing a dissolved amount of Zr as ZrN, effective to inhibit dissociation of the UN phase.

  6. Rapid determination of 226Ra in environmental samples

    SciTech Connect (OSTI)

    Maxwell, Sherrod L.; Culligan, Brian K.

    2012-02-04

    A new rapid method for the determination of {sup 228}Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/ Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine {sup 228}Ra in solid samples (via {sup 228}Ac) , radiochemical methods that employ gas flow proportional counting techniques typically provide lower MDA (Minimal Detectable Activity) levels for the determination of {sup 228}Ra in water samples. Most radiochemical methods for {sup 228}Ra collect and purify {sup 228}Ra and allow for {sup 228}Ac daughter ingrowth for ~36 hours. In this new SRNL/EBL approach, {sup 228}Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 hours so that {sup 228}Ra assay results on water samples can be achieved in < 6 hours. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90%), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. {sup 228}Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify {sup 228}Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and {sup 90}Y. La is used to determine {sup 228}Ac chemical yield via ICP-MS, but {sup 133}Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

  7. RAPID DETERMINATION OF RA-226 IN ENVIRONMENTAL SAMPLES

    SciTech Connect (OSTI)

    Maxwell, S.

    2012-01-03

    A new rapid method for the determination of {sup 226}Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. {sup 226}Ra (T1/2 = 1,620 years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine {sup 226}Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove {sup 225}Ac and potential interferences. The purified {sup 226}Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of {sup 226}Ra in environmental samples can be performed in less than 16 h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6 h. {sup 225}Ra (T1/2 = 14.9 day) tracer is used and the {sup 225}Ra progeny {sup 217}At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any

  8. Valence electronenergy-lossspectroscopystudyofZrSiO4 and ZrO2

    SciTech Connect (OSTI)

    Spence, John; Jiang, Nan

    2013-07-01

    ZrSiO4 (zircon) and m-ZrO2 (zirconia) are fundamental and industrially important materials.This work reports the detailed valence electron energy-loss spectroscopy (VEELS) studies of these compounds. The dielectric response functions, as well as single-electron interband transition spectra,are derived from VEELS data for both ZrSiO4 and m-ZrO2, in the rang e550 eV using the KramersKronig analysis method. Our interpretation of the interband transitions is given with the aid of ab initio calculations of density of states. The bandgap energies for both materials are also measured using VEELS.The surface and bulk plasmons are identified: the surface plasmon peaks locate at around 12 eV,and two bulk plasmon peaks are ~1516 eV and ~2527 eV,respectively.Although similarities in the VEELS exist between ZrSiO4 and m-ZrO2, two majo rdifferences are als onoticed and explained in terms of composition and structure differences.

  9. Upcoming P&RA CoP Activities | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Upcoming P&RA CoP Activities Upcoming P&RA CoP Activities Upcoming Activities Software QA requirements for supporting environmental management decisions (TBD). Annual Technical Exchange Meeting (October, 2016; Date & Location TBD)

  10. Examination Report: OAS-RA-13-06 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report: OAS-RA-13-06 Examination Report: OAS-RA-13-06 January 17, 2013 Montgomery County Department of Housing and Community Affairs - Weatherization Assistance Program ...

  11. Audit Letter Report: OAS-RA-L-10-09 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    9 Audit Letter Report: OAS-RA-L-10-09 August 27, 2010 Office of Science's Energy Frontier ... Topic: Science & Innovation Audit Letter Report: OAS-RA-L-10-09 (107.26 KB) More Documents ...

  12. Audit Report: OAS-RA-13-15 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    5 Audit Report: OAS-RA-13-15 March 21, 2013 The Department of Energy's Industrial Carbon ... Topic: Financial Asssitance Audit Report: OAS-RA-13-15 (466.71 KB) More Documents & ...

  13. Audit Report: OAS-RA-L-12-05 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2-05 Audit Report: OAS-RA-L-12-05 July 10, 2012 Follow-up on the Department of Energy's ... Components Program under the American Recovery and Reinvestment Act (OAS-RA-L-10-04). ...

  14. Audit Report: OAS-RA-11-14 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-11-14 August 25, 2011 The Department of Energy's Weatherization ... Weatherization Assistance Program," (OAS-RA-10-11), identified several issues that ...

  15. Audit Report: OAS-RA-13-07 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Audit Report: OAS-RA-13-07 January 17, 2013 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-13-07 (566.45 KB) More Documents & ...

  16. Audit Letter Report: OAS-RA-L-10-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Letter Report: OAS-RA-L-10-02 April 16, 2010 Audit of Fermi National Accelerator ... Topic: Science & Innovation Audit Letter Report: OAS-RA-L-10-02 (94.57 KB) More Documents ...

  17. Audit Report: OAS-RA-11-17 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Audit Report: OAS-RA-11-17 September 19, 2011 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-11-17 (706.78 KB) More Documents & ...

  18. Audit Report: OAS-RA-12-08 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Audit Report: OAS-RA-12-08 April 19, 2012 The Department of Energy's American Recovery ... Topic: Financial Assistance Audit Report: OAS-RA-12-08 (1.84 MB) More Documents & ...

  19. Examination Report: OAS-RA-13-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Examination Report: OAS-RA-13-04 November 8, 2012 The Department of Energy's American ... Topic: Financial Assistance Examination Report: OAS-RA-13-04 (1.34 MB) More Documents & ...

  20. Audit Report: OAS-RA-10-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-10-02 December 3, 2009 Management Alert on the Department's ... Topic: Financial Assistance Audit Report: OAS-RA-10-02 (138.19 KB) More Documents & ...

  1. Special Report: OAS-RA-10-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Special Report: OAS-RA-10-01 October 21, 2009 The Department of Energy's Quality ... Topic: Financial Assistance Special Report: OAS-RA-10-01 (133.68 KB) More Documents & ...

  2. Audit Report: OAS-RA-13-28 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Audit Report: OAS-RA-13-28 July 18, 2013 Costs Incurred by Selected Tribal Energy ... TOPIC: Financial Assistance AUDIT REPORT: OAS-RA-13-28 (545.92 KB) More Documents & ...

  3. Audit Report: OAS-RA-11-13 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    13 Audit Report: OAS-RA-11-13 August 23, 2011 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-11-13 (398.06 KB) More Documents & ...

  4. Examination Report: OAS-RA-13-24 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Examination Report: OAS-RA-13-24 June 18, 2013 Southwest Michigan Community Action ... TOPIC: Energy OAS-RA-13-24.pdf (1.91 MB) More Documents & Publications Examination Report: ...

  5. Audit Report: OAS-RA-12-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-12-12 May 22, 2012 The Department of Energy's Clean Cities ... Topic: Financial Assistance Audit Report: OAS-RA-12-12 (761.22 KB) More Documents & ...

  6. Special Report: OAS-RA-10-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Special Report: OAS-RA-10-04 February 19, 2010 Progress in Implementing the Department ... Topic: Financial Assistance Special Report: OAS-RA-10-04 (232.52 KB) More Documents & ...

  7. Audit Report: OAS-RA-L-11-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Audit Report: OAS-RA-L-11-01 November 10, 2010 Management of the Plutonium Finishing ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-01 (129.83 KB) More Documents & ...

  8. Audit Report: OAS-RA-L-11-13 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Audit Report: OAS-RA-L-11-13 September 30, 2011 The 12 GeV CEBAF Upgrade Project at ... Topic: Science & Innovation Audit Report: OAS-RA-L-11-13 (86.05 KB) More Documents & ...

  9. Audit Report: OAS-RA-11-15 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    5 Audit Report: OAS-RA-11-15 August 25, 2011 Los Alamos National Laboratory Environmental ... Topic: Environmental Cleanup Audit Report: OAS-RA-11-15 (125.15 KB) More Documents & ...

  10. Audit Report: OAS-RA-10-06 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    06 Audit Report: OAS-RA-10-06 April 1, 2010 Accounting and Reporting for the American ... Topic: Management & Administration Audit Report: OAS-RA-10-06 (163.51 KB) More Documents & ...

  11. Audit Report: OAS-RA-10-10 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    10 Audit Report: OAS-RA-10-10 May 25, 2010 Waste Processing and Recovery Act Acceleration ... Topic: Environmental Cleanup Audit Report: OAS-RA-10-10 (658.07 KB) More Documents & ...

  12. Audit Report: OAS-RA-L-11-09 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    9 Audit Report: OAS-RA-L-11-09 July 7, 2011 Performance of Recovery Act Funds at the Waste ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-09 (99.67 KB) More Documents & ...

  13. Examination Report: OAS-RA-13-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    12 Examination Report: OAS-RA-13-12 February 19, 2013 City of Los Angeles - Energy ... Topic: Financial Assistance Examination Report: OAS-RA-13-12 (790.07 KB) More Documents & ...

  14. Audit Report: OAS-RA-12-07 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Audit Report: OAS-RA-12-07 April 6, 2012 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-12-07 (528.89 KB) More Documents & ...

  15. Audit Letter Report: OAS-RA-L-10-06 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    6 Audit Letter Report: OAS-RA-L-10-06 September 15, 2010 The Department of Energy's ... Topic: Financial Assistance Audit Letter Report: OAS-RA-L-10-06 (140.87 KB) More Documents ...

  16. Audit Report: OAS-RA-12-06 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    6 Audit Report: OAS-RA-12-06 February 22, 2012 The Management of Post-Recovery Act ... Topic: Human Resources Audit Report: OAS-RA-12-06 (250 KB) More Documents & Publications ...

  17. Audit Report: OAS-RA-14-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-14-04 June 17, 2014 Selected Activities of the Office of Energy ... Topic: Financial Assistance Audit Report: OAS-RA-14-04 (334.32 KB) More Documents & ...

  18. Examination Report: OAS-RA-L-12-07 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    L-12-07 Examination Report: OAS-RA-L-12-07 September 20, 2012 The Department of Energy's ... Topic: Financial Assistance Examination Report: OAS-RA-L-12-07 (2.05 MB) More Documents & ...

  19. Audit Report: OAS-RA-11-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-11-12 August 22, 2011 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-11-12 (2.6 MB) More Documents & ...

  20. Audit Special Report: OAS-RA-10-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    OAS-RA-10-03 Audit Special Report: OAS-RA-10-03 December 7, 2009 Selected Department of Energy Program Efforts to Implement the American Recovery and Reinvestment Act The American ...

  1. Audit Report: OAS-RA-12-13 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Audit Report: OAS-RA-12-13 June 25, 2012 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-12-13 (561.48 KB) More Documents & ...

  2. Examination Report: OAS-RA-12-05 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report: OAS-RA-12-05 Examination Report: OAS-RA-12-05 January 20, 2012 Saratoga County Economic Opportunity Council, Inc. -Weatherization Assistance Program Funds ...

  3. Examination Report: OAS-RA-13-05 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report: OAS-RA-13-05 Examination Report: OAS-RA-13-05 January 17, 2013 Prince George's County Department of Housing and Community Development - Weatherization ...

  4. Audit Report: OAS-RA-L-11-08 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Audit Report: OAS-RA-L-11-08 May 19, 2011 Use of American Recovery and Reinvestment Act ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-08 (108.8 KB) More Documents & ...

  5. Audit Report: OAS-RA-11-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-11-02 November 2, 2010 Selected Aspects of the Commonwealth of ... Topic: Financial Assistance Audit Report: OAS-RA-11-02 (231.31 KB) More Documents & ...

  6. Preliminary Audit Report: OAS-RA-10-11 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Preliminary Audit Report: OAS-RA-10-11 Preliminary Audit Report: OAS-RA-10-11 May 26, 2010 Management Controls over the Commonwealth of Virginia's Efforts to Implement the American ...

  7. Audit Report: OAS-RA-09-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    09-04 Audit Report: OAS-RA-09-04 September 4, 2009 Department of Energy's Efforts to Meet ... Topic: Management and Administration Audit Report: OAS-RA-09-04 (1.75 MB) More Documents & ...

  8. Audit Report: OAS-RA-12-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-12-04 January 20, 2012 The Department's Management of the Smart ... Topic: Financial Assistance Audit Report: OAS-RA-12-04 (365.11 KB) More Documents & ...

  9. Audit Report: OAS-RA-L-11-10 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 Audit Report: OAS-RA-L-11-10 July 21, 2011 Department of Energy's Controls over Recovery ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-10 (275.01 KB) More Documents & ...

  10. Special Report: OAS-RA-L-14-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    L-14-01 Special Report: OAS-RA-L-14-01 April 14, 2014 Allegations Regarding the Department ... Topic: Management and Administration Special Report: OAS-RA-L-14-01 (118.07 KB) More ...

  11. Special Report: OAS-RA-L-12-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    L-12-01 Special Report: OAS-RA-L-12-01 November 28, 2011 Special Inquiry on the Office of ... Topic: Management & Administration Special Report: OAS-RA-L-12-01 (109.71 KB) More ...

  12. Inspection Report: INS-RA-L-12-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    RA-L-12-01 Inspection Report: INS-RA-L-12-01 December 16, 2011 Waste Disposal and Recovery Act Efforts at the Oak Ridge Reservation The Department of Energy (Department) expends ...

  13. Audit Report: OAS-RA-L-11-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Audit Report: OAS-RA-L-11-03 February 9, 2011 Management of the Tank Farm Recovery Act ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-03 (79.04 KB) More Documents & ...

  14. Investigative Report: INV-RA-11-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Investigative Report: INV-RA-11-01 Investigative Report: INV-RA-11-01 December 3, 2010 Management Alert on the State Energy Efficient Appliance Rebate Program The purpose of this ...

  15. Audit Report: OAS-RA-L-11-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1-04 Audit Report: OAS-RA-L-11-04 March 2, 2011 The Department's Infrastructure ... Topic: Management & Administration Audit Report: OAS-RA-L-11-04 (87.38 KB) More Documents ...

  16. Special Report: OAS-RA-14-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Special Report: OAS-RA-14-01 October 31, 2013 Recent Events Related to Ecotality, Inc. ... Million in Funding to Ecotality, Inc. (OAS-RA-13-29, July 2013), we found that the ...

  17. Audit Report: OAS-RA-11-05 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    5 Audit Report: OAS-RA-11-05 March 22, 2011 The Department of Energy's Geothermal ... Topic: Energy Audit Report: OAS-RA-11-05 (4.36 MB) More Documents & Publications Revised ...

  18. Audit Report: OAS-RA-L-12-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2-02 Audit Report: OAS-RA-L-12-02 January 12, 2012 Recovery Act Funded Projects at the ... Topic: Management & Administration Audit Report: OAS-RA-L-12-02 (100.04 KB) More Documents ...

  19. Audit Report: OAS-RA-11-09 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    9 Audit Report: OAS-RA-11-09 June 13, 2011 The Department of Energy's Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-11-09 (995.84 KB) More Documents & ...

  20. Examination Report: OAS-RA-13-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report: OAS-RA-13-02 Examination Report: OAS-RA-13-02 October 9, 2012 County of Los Angeles - Energy Efficiency and Conservation Block Grant Program Funds Provided by ...

  1. Audit Report: OAS-RA-12-11 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    11 Audit Report: OAS-RA-12-11 May 10, 2012 The Department of Energy's Transportation ... Topic: Financial Assistance Special Report: OAS-RA-12-11 (109.56 KB) More Documents & ...

  2. Audit Letter Report: OAS-RA-L-10-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Letter Report: OAS-RA-L-10-04 April 27, 2010 Progress in Implementing the Advanced ... Topic: Financial Assistance Audit Letter Report: OAS-RA-L-10-04 (69.61 KB) More Documents ...

  3. Audit Report: OAS-RA-10-17 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Audit Report: OAS-RA-10-17 September 21, 2010 Status Report: The Department of Energy's ... Topic: Financial Assistance Audit Report: OAS-RA-10-17 (624.07 KB) More Documents & ...

  4. Audit Report: OAS-RA-10-18 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Audit Report: OAS-RA-10-18 September 29, 2010 Management Controls over the Department of ... Topic: Financial Assistance Audit Report: OAS-RA-10-18 (649.61 KB) More Documents & ...

  5. Audit Report: OAS-RA-L-11-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-L-11-02 December 20, 2010 Audit of Environmental Cleanup Projects ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-02 (123.69 KB) More Documents & ...

  6. Examination Report: OAS-RA-13-21 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Examination Report: OAS-RA-13-21 May 14, 2013 South Carolina Energy Office - Energy ... TOPIC: Financial Assistance Examination Report: OAS-RA-13-21 (245.49 KB) More Documents & ...

  7. Audit Report: OAS-RA-L-11-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-L-11-12 September 29, 2011 Implementation of the Recovery Act at ... Topic: Environmental Cleanup Audit Report: OAS-RA-L-11-12 (79.15 KB) More Documents & ...

  8. Audit Report: OAS-RA-11-01 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Audit Report: OAS-RA-11-01 October 14, 2010 The State of Illinois Weatherization ... Topic: Financial Assistance Audit Report: OAS-RA-11-01 (898.49 KB) More Documents & ...

  9. Audit Report: OAS-RA-L-13-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-L-13-04 July 9, 2013 Modular Office Facilities for Recovery Act ... TOPIC: Management & Administration Audit Report: OAS-RA-L-13-04 (364.66 KB) More Documents ...

  10. Audit Report: OAS-RA-11-11 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Audit Report: OAS-RA-11-11 August 22, 2011 The Advanced Research Projects The Advanced ... Topic: Management & Administration Audit Report: OAS-RA-11-11 (772.55 KB) More Documents & ...

  11. Performance & Risk Assessment Community of Practice (P&RA CoP...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Performance & Risk Assessment Community of Practice (P&RA CoP) Technical Exchanges Performance & Risk Assessment Community of Practice (P&RA CoP) Technical Exchanges PA CoP has ...

  12. Attendees - December 15-16, 2015 P&RA Technical Exchange Meeting |

    Office of Environmental Management (EM)

    Department of Energy 15-16, 2015 P&RA Technical Exchange Meeting Attendees - December 15-16, 2015 P&RA Technical Exchange Meeting Attendees to the December 15-16, 2015 P&RA Technical Exchange Meeting. Attendees (10.35 KB) More Documents & Publications Attendees - December 2014 P&RA Technical Exchange Meeting Status Updates on the Performance and Risk Assessment Community of Practice Status Updates on the Performance and Risk Assessment Community of Practice (P&RA CoP)

  13. Crystal structure of high-Zr inclusions in an alloy containing U, Pu, Np, Am, Zr and rare-earth elements

    SciTech Connect (OSTI)

    Dawn E. Janney; James W. Madden; J. Rory Kennedy; Thomas P. O'Holleran

    2014-05-01

    Researchers commonly observe high-Zr inclusions in actinide-Zr alloys. As there is very little published data on the crystal structures of these inclusions, it has generally been assumed that the inclusions were impurity-stabilized a-Zr. However, new electron-diffraction data from two high-Zr inclusions in an alloy containing U, Pu, Np, Am, Zr, and rare-earth elements show that these inclusions are not a-Zr (which has a hexagonal structure) but instead have a face-centered cubic structure. This data is unique in that it combines single-crystal diffraction patterns and microchemical analyses from individual inclusions. More data on other high-Zr inclusions is clearly required. However, the present results suggest that caution is needed in assuming that all high-Zr inclusions in actinide-Zr alloys are a-Zr.

  14. Irradiation induced structural change in Mo2Zr intermetallic phase

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gan, J.; Keiser, Jr., D. D.; Miller, B. D.; Eriksson, N.; Sohn, Y. H.; Kirk, M.

    2016-05-14

    The Mo2Zr phase has been identified as a major interaction product at the interface of U-10Mo and Zr. Transmission electron microscopy in-situ irradiation with Kr ions at 200 °C with doses up to 2.0E + 16 ions/cm2 was carried out to investigate the radiation stability of the Mo2Zr. The Mo2Zr undergoes a radiation-induced structural change, from a large cubic (cF24) to a small cubic (cI2), along with an estimated 11.2% volume contraction without changing its composition. The structural change begins at irradiation dose below 1.0E + 14 ions/cm2. Furthermore, the transformed Mo2Zr phase demonstrates exceptional radiation tolerance with the developmentmore » of dislocations without bubble formation.« less

  15. Pulsed chemical HF laser with a large discharge gap

    SciTech Connect (OSTI)

    Azarov, M A; Klimuk, Evgenii A; Kutumov, Konstantin A; Troshchinenko, G A; Lacour, Bernard M

    2004-11-30

    The characteristics of the radiation emitted by an electric-discharge pulsed chemical HF laser with a discharge gap of 10 cm are studied. The discharge was stabilised by a semiconducting ferroelectric ceramic layer deposited on plane metal electrodes. The specific energy and technical efficiency were 3 J L{sup -1} and 3.4%, respectively, for a laser operating on a nonchain reaction in SF{sub 6}-H{sub 2} mixture and 25 J L{sup -1} and 26%, respectively, for a laser operating on a chain reaction in F{sub 2}-O{sub 2}-SF{sub 6}-H{sub 2} mixture. (lasers)

  16. The Bayo Canyon/radioactive lanthanum (RaLa) program

    SciTech Connect (OSTI)

    Dummer, J.E.; Taschner, J.C.; Courtright, C.C.

    1996-04-01

    LANL conducted 254 radioactive lanthanum (RaLa) implosion experiments Sept. 1944-March 1962, in order to test implosion designs for nuclear weapons. High explosives surrounding common metals (surrogates for Pu) and a radioactive source containing up to several thousand curies of La, were involved in each experiment. The resulting cloud was deposited as fallout, often to distances of several miles. This report was prepared to summarize existing records as an aid in evaluating the off-site impact, if any, of this 18-year program. The report provides a historical setting for the program, which was conducted in Technical Area 10, Bayo Canyon about 3 miles east of Los Alamos. A description of the site is followed by a discussion of collateral experiments conducted in 1950 by US Air Force for developing an airborne detector for tracking atmospheric nuclear weapons tests. All known off-site data from the RaLa program are tabulated and discussed. Besides the radiolanthanum, other potential trace radioactive material that may have been present in the fallout is discussed and amounts estimated. Off-site safety considerations are discussed; a preliminary off-site dose assessment is made. Bibliographical data on 33 persons important to the program are presented as footnotes.

  17. Evolution of magnetic properties and microstructure of Hf2Co11B...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Evolution of magnetic properties and microstructure of Hf2Co11B alloys Citation Details In-Document Search Title: Evolution of magnetic properties and ...

  18. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; McAlister, Daniel R.

    2016-03-24

    A new method that rapidly preconcentrates and measures 226Ra from hydraulic fracturing wastewater samples was developed in the Savannah River Environmental Laboratory. The method improves the quality of 226Ra measurements using gamma spectrometry by providing up to 100x preconcentration of 226Ra from this difficult sample matrix, which contains very high levels of calcium, barium, strontium, magnesium and sodium. The high chemical yield, typically 80-90%, facilitates a low detection limit, important for lower level samples, and indicates method ruggedness. Ba-133 tracer is used to determine chemical yield and correct for geometry-related counting issues. The 226Ra sample preparation takes < 2 hours.

  19. P&RA CoP Webinars | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Services » Site & Facility Restoration » P&RA Community of Practice » P&RA CoP Webinars P&RA CoP Webinars Topics of interest to the CoP have been identified with the help of the steering committee, and will be discussed in quarterly Webinars. List of Topics for Interagency Performance & Risk Assessment Community of Practice (P&RA CoP) Discussion May 16, 2016 Webinar - Predicting the Service Life of Geomembranes in Low-Level and Mixed-Waste Disposal Facilities

  20. Measurement and analysis of muonic x rays of 176,177,178,179,180Hf

    SciTech Connect (OSTI)

    Tanaka, Y.; Steffen, R.M.; Shera, E.B.; Reuter, W.; Hoehn, M.V.; Zumbro, J.D.

    1984-07-01

    Monopole and quadrupole charge distributions of /sup 176/Hf, /sup 177/Hf, /sup 178/Hf, /sup 179/Hf, and /sup 180/Hf were investigated by muonic atom K and L x-ray measurements. The model-independent Barrett charge radii R/sub k/ and the isotope shifts ..delta..R/sub k/ were measured, and values of and ..delta.. were deduced. A weak odd-even staggering of the nuclear charge radii was observed for the series /sup 176 -178/Hf and /sup 178 -180/Hf. A large negative isomer shift was observed in the 2/sup +/ state of the /sup 176/Hf nucleus, a fact that existing theories do not explain. The quadrupole moments of the first excited states of the hafnium nuclei were determined to be Q/sup 176/(2/sup +/) = -2.10(2) e b, Q/sup 177/((9/2)/sup -/) = 1.30(2) e b, Q/sup 178/(2/sup +/) = -2.02(2) e b, Q/sup 179/((11/2)/sup +/) = 1.88(3) e b, and Q/sup 180/(2/sup +/) = -2.00(2) e b. These quadrupole moments and the simultaneously determined B(E2) values for the respective nuclei are in satisfactory agreement with the predictions of the axially symmetric rotor model.

  1. Measurements of structural and chemical order in Zr80Pt20 and Zr77Rh23 liquids

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Johnson, M. L.; Blodgett, M. E.; Lokshin, K. A.; Mauro, N. A.; Neuefeind, J.; Pueblo, C.; Quirinale, D. G.; Vogt, A. J.; Egami, T.; Goldman, A. I.; et al

    2016-02-03

    In this study, the short-range order (SRO) and medium-range order of electrostatically levitated Zr80Pt20 and Zr77Rh23 liquids are presented founded on a combination of high-energy x-ray diffraction and time-of-flight neutron diffraction studies. The atomic structures of the Zr80Pt20 liquids were determined as a function of temperature from constrained reverse Monte Carlo simulations using x-ray and elastic neutron scattering measurements and two partial pair-distribution functions obtained from molecular dynamics (MD) simulations.

  2. An Exceptionally Stable, Porphyrinic Zr Metal-Organic Framework...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Exceptionally Stable, Porphyrinic Zr Metal-Organic Framework Exhibiting pH-Dependent Fluorescence Previous Next List Hai-Long Jiang, Dawei Feng, Kecheng Wang, Zhi-Yuan Gu, ...

  3. DFT STUDY REVISES INTERSTITIAL CONFIGURATIONS IN HCP Zr

    SciTech Connect (OSTI)

    Samolyuk, German D; Golubov, Stanislav I; Osetskiy, Yury N; Stoller, Roger E

    2012-06-01

    Analysis of experimental result on microstructure evolution in irradiated Zr and alloys has demonstrated that available knowledge on self-interstitial defects in Zr is in contradiction. We therefore have initiated an extensive theoretical and modeling program to clarify this issue. In this report we present first ab initio calculations results of single SIA configurations in Zr. We demonstrate importance of simulations cell size, applied exchange-correlation functional and simulated c/a ratio. The results obtained demonstrate clearly that the most stable configurations are in basal plane and provide some evidences for enhanced interstitial transport along basal planes. The results obtained will be used in generation a new interatomic potential for Zr to be used in large-scale atomistic modeling of mechanisms relevant for radiation-induced microstructure evolution.

  4. The analysis of Ytrium doped BaZrO3

    Office of Scientific and Technical Information (OSTI)

    Enhanced Power Stability for Proton Conducting Solid Oxides Fuel Cells Report Title: Computational modeling, synthesis, and characterization of BaZr 1-x Y x O 3- solid state ...

  5. Construction of Ultrastable Porphyrin Zr Metal-Organic Frameworks...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A series of highly stable MOFs with 3-D nanochannels, namely PCN-224 (no metal, Ni, Co, Fe), have been assembled with six-connected Zr6 cluster and metalloporphyrins by a...

  6. A correlation between soil descriptions and {sup 226}Ra concentrations in Florida soils

    SciTech Connect (OSTI)

    Harrison, D.P.

    1992-12-31

    The soil radium content in Florida is highly variable. The range in radium concentrations, where the samples involved in this study are concerned, is from 0.1 pCi/g to 18.5 pCi/g. Low {sup 226}Ra concentrations (0.1 to 5 pCi/g) are evidenced in sands, moderate concentrations (5 to 11 pCi/g) are found in silt and gravel, and high {sup 226}Ra concentrations (>11 pCi/g) are found in soil horizons with shell, clay, and strata with phosphate. Strata containing phosphate yields a high concentration of {sup 226}Ra. The information obtained in this study, soil descriptions with their corresponding {sup 226}Ra concentrations, comes from geological cores drilled by geotechnical consultants with gamma spectrometry analysis performed by high resolution gamma spectroscopy. Concentration; of {sup 226}Ra generally increase with depth. These cores are usually terminated at 20 feet deep, with some cores being shallower than this due to hitting bedrock or encountering the water table. These frequency distributions give the core-logging geologist an approximate concentration of {sup 226}Ra based on the description of the soil. Since the correlation of {sup 226}Ra and soil descriptions can be used as a tool in assigning indoor radon potential, this study is of importance to land managers, contractors, developers, and regulating agencies who are attempting to place standards on tracts of land with {sup 226}Ra concentration used as a criterion.

  7. Audit Letter Report: OAS-RA-L-11-05 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1-05 Audit Letter Report: OAS-RA-L-11-05 March 8, 2011 Recovery Act Funded Projects at the ... Topic: Science & Innovation Audit Letter Report: OAS-RA-L-11-05 (104.28 KB) More Documents ...

  8. Ab initio molecular dynamics simulations of short-range order in Zr50Cu45Al5 and Cu50Zr45Al5 metallic glasses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Kramer, M. J.; Ho, K. M.

    2016-02-01

    In this study, comparative analysis between Zr-rich Zr50Cu45Al5 and Cu-rich Cu50Zr45Al5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr50Cu45Al5 and Cu50Zr45Al5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons <0,0,12,0> is dominant, and in the Cu-rich one the distorted icosahedral orders, especially <0,2,8,2> and <0,2,8,1>, are prominent. And the <0,2,8,2> polyhedra in Cu50Zr45Al5 MG mainly originate from Al-centeredmore » clusters, while the <0,0,12,0> in Zr50Cu45Al5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. The relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr50Cu45Al5.« less

  9. Ab initio molecular dynamics simulations of short-range order in Zr50Cu45Al5 and Cu50Zr45Al5 metallic glasses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Kramer, M. J.; Ho, K. M.

    2016-02-01

    Comparative analysis between Zr-rich Zr50Cu45Al5 and Cu-rich Cu50Zr45Al5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr50Cu45Al5 and Cu50Zr45Al5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons < 0,0,12,0 > is dominant, and in the Cu-rich one the distorted icosahedral orders, especially < 0,2,8,2 > and < 0,2,8,1 >, are prominent. And the < 0,2,8,2 > polyhedra in Cu50Zr45Al5more » MG mainly originate from Al-centered clusters, while the < 0,0,12,0 > in Zr50Cu45Al5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. Lastly, the relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr50Cu45Al5.« less

  10. Synthesis and characterization of lanthanum phosphate nanoparticles as carriers for 223Ra and 225Ra for targeted alpha therapy

    SciTech Connect (OSTI)

    Rojas, J. V.; Woodward, J. D.; Chen, N.; Rondinone, A. J.; Castano, C. H.; Mirzadeh, S.

    2015-03-19

    Targeted alpha therapy (TAT) has the potential for killing specific tumor cells with minimum collateral damage to surrounding healthy tissue. Radionuclides such as 223Ra, 225Ra, and 225Ac are of special interest for radiotherapeutic applications as they emit multiple -particles during their decay. Utilizing appropriate carriers capable of retaining both the parent radioisotope as well as daughter products is important for the effective delivery of the radioisotope to the tumor site while mitigating global in vivo radiotoxicity. Methods. In this work, core and core+2 shells (NPs with 2 additional layers of cold LaPO4 deposited on the core surfaces) LaPO4 nanoparticles (NPs) were synthesized containing either 223Ra or 225Ra/225Ac and the retention of the parents and daughters within the NPs in vitro was investigated. Results. The NPs crystallized in rhabdophane phase with mean diameters of 3.4 and 6.3 nm for core and core+2 shells, respectively. The core LaPO 4 NPs retained up to 88% of 223Ra over 35 days. However, in the core+2 shell NPs, the retention of 223Ra and its daughter, 211Pb, was improved to > 99.9% over 27 days. Additionally, the retention of 225Ra/225Ac parents was > 99.98% and ~80% for the 221Fr and 213Bi daughters over 35 days for the core+2 shell NPs. Conclusions. These results suggest that LaPO4 NPs are potentially effective carriers of radium isotopes.

  11. Pygmy dipole strength in {sup 90}Zr

    SciTech Connect (OSTI)

    Schwengner, R.; Rusev, G.; Benouaret, N.; Beyer, R.; Erhard, M.; Junghans, A. R.; Klug, J.; Kosev, K.; Nair, C.; Schilling, K. D.; Wagner, A.; Tsoneva, N.; Grosse, E.; Lenske, H.

    2008-12-15

    The dipole response of the N=50 nucleus {sup 90}Zr was studied in photon-scattering experiments at the electron linear accelerator ELBE with bremsstrahlung produced at kinetic electron energies of 7.9, 9.0, and 13.2 MeV. We identified 189 levels up to an excitation energy of 12.9 MeV. Statistical methods were applied to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. In this way we derived the photoabsorption cross section up to the neutron-separation energy. This cross section matches well the photoabsorption cross section obtained from ({gamma}, n) data and thus provides information about the extension of the dipole-strength distribution toward energies below the neutron-separation energy. An enhancement of E1 strength has been found in the range of 6 to 11 MeV. Calculations within the framework of the quasiparticle-phonon model ascribe this strength to a vibration of the excessive neutrons against the N=Z neutron-proton core, giving rise to a pygmy dipole resonance.

  12. List of Topics for Interagency Performance & Risk Assessment Community of Practice (P&RA CoP) Discussion

    Office of Energy Efficiency and Renewable Energy (EERE)

    List of Topics for Interagency Performance & Risk Assessment Community of Practice (P&RA CoP) Discussion

  13. Interagency Performance and Risk Assessment Community of Practice (P&RA

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    CoP) Charter | Department of Energy Interagency Performance and Risk Assessment Community of Practice (P&RA CoP) Charter Interagency Performance and Risk Assessment Community of Practice (P&RA CoP) Charter Charter for the Interagency Performance and Risk Assessment Community of Practice (P&RA CoP) whose goal is to foster exchange of information regarding preparation of P&RAs across agencies and practitioners; enhance consistency in the preparation of P&RAs across the

  14. DRAFT Letter, PW 1/3/6 RD/RA Work Plan 1/19/16

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Letter, PW 1/3/6 RD/RA Work Plan 1/19/16 RAP Committee: Draft Letter: Remedial Design/Remedial Action (RD/RA) Work Plan for the 200-CW-5, 200- PW-1, PW-3, PW-6 Operable Units, DOE/RL-2015-23 (Draft B). Page 1 of 1 Draft HAB Letter: Remedial Design/Remedial Action (RD/RA) Work Plan for the 200- CW-5, 200-PW-1, PW-3, PW-6 Operable Units, DOE/RL-2015-23 (Draft B). Issue Managers: Engstrom, Hudson, Niles, Cimon, Mattson To: Stacy and Dennis Cc: Ecology and DOE HQ (Monica), Bertrand Recognizing that

  15. Microsoft Word - A10RA010 Report Cover 12-6-10

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Audits and Inspections Audit Report Audit of Environmental Cleanup Projects Funded by the Recovery Act at the Y-12 National Security Complex OAS-RA-L-11-02 December 2010 DOE F 1325.8 (08-93) United States Government Department of Energy Memorandum DATE: December 20, 2010 Audit Report Number: OAS-RA-L-11-02 REPLY TO ATTN OF: IG-32 (A10RA010) SUBJECT: Audit Report on "Environmental Cleanup Projects Funded by the Recovery Act at the Y-12 National Security Complex" TO: Manager, Y-12 Site

  16. HF-modified piping in hydroprocessing industry: A user`s perspective

    SciTech Connect (OSTI)

    Bagdasarian, A.J.; Singh, A.K.; Gaugler, R.J.

    1995-12-01

    HF-modified austenitic stainless steel cast piping has been in use in hydroprocessing reactor effluent high pressure loop for 35 years. Recent process modifications resulted in replacement of piping in a hydrocracking unit which was in service for 25 years. This paper reports on mechanical and metallurgical investigations of the replaced piping as well as samples removed from newer vintage HF-modified piping. The investigations show susceptibility to sensitization of HF-modified materials when exposed to the hydroprocessing operating temperature range. Loss of room temperature impact properties was also observed. Realistic flow tolerance of the HF-modified material was established by CTOD tests and a relationship is proposed between the CTOD values and Charpy V-notch values. The paper also describes three case histories where the failures resulted from the polythionic acid attack.

  17. Local Metal and Deuterium Ordering in the Deuterated ZrTiNi C14...

    Office of Scientific and Technical Information (OSTI)

    Local Metal and Deuterium Ordering in the Deuterated ZrTiNi C14 Laves Phase Citation Details In-Document Search Title: Local Metal and Deuterium Ordering in the Deuterated ZrTiNi ...

  18. Audit Report: OAS-RA-13-15 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Audit Report: OAS-RA-13-15 March 21, 2013 The Department of Energy's Industrial Carbon Capture and Storage Program Funded by the American Recovery and Reinvestment Act The ...

  19. Audit Report: OAS-RA-13-31 | Department of Energy

    Energy Savers [EERE]

    Audit Report: OAS-RA-13-31 September 27, 2013 The Department of Energy's Hydrogen and Fuel Cells Program The Department of Energy spent approximately 1 billion over the last 5...

  20. Audit Report: OAS-RA-L-11-06 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    6 Audit Report: OAS-RA-L-11-06 April 1, 2011 Department's Management of Cloud Computing Services Cloud computing enables convenient, on-demand access to shared computing resources...

  1. Audit Report: OAS-RA-L-13-01 | Department of Energy

    Energy Savers [EERE]

    Audit Report: OAS-RA-L-13-01 November 1, 2012 Implementation of the Department of Energy's Concentrating Solar Power Program The Department of Energy's (Department) Office of ...

  2. Examination Report: OAS-RA-13-09 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report: OAS-RA-13-09 February 19, 2013 North Carolina State Energy Office - ... The North Carolina State Energy Office's (Agency) received a 20.9 million competitive ...

  3. Biosketches of Speakers- P&RA CoP December 2014 Technical Exchange Meeting

    Office of Energy Efficiency and Renewable Energy (EERE)

    Bio-sketches of Speakers from the Performance & Risk Assessment Community of Practice (P&RA) Technical Exchange Meeting held in Las Vegas, Nevada on December 11 & 12, 2014.

  4. Examination Report: OAS-RA-13-13 | Department of Energy

    Energy Savers [EERE]

    Examination Report: OAS-RA-13-13 February 21, 2013 Texas State Energy Conservation Office ... The Texas State Energy Conservation Office (Agency) received a 45.6 million grant award ...

  5. Rapid determination of 226Ra in emergency urine samples

    SciTech Connect (OSTI)

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed. The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.

  6. Examination Report: OAS-RA-13-02 | Department of Energy

    Office of Environmental Management (EM)

    Examination Report: OAS-RA-13-02 Examination Report: OAS-RA-13-02 October 9, 2012 County of Los Angeles - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Energy Efficiency and Conservation Block Grant (EECBG) Program received $3.2 billion to develop, promote, implement and manage energy efficiency and conservation projects and programs

  7. EXAMINATION REPORT: OAS-RA-13-27 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    EXAMINATION REPORT: OAS-RA-13-27 EXAMINATION REPORT: OAS-RA-13-27 July 15, 2013 Commonwealth of Puerto Rico Energy Affairs Administration - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Energy Efficiency and Conservation Block Grant (EECBG) Program received $3.2 billion to develop, promote, implement and manage energy efficiency and

  8. Interdiffusion and Reaction between Zr and Al Alloys from 425 degrees to 625 degrees C

    SciTech Connect (OSTI)

    J. Dickson; L. Zhou; A. Ewh; M. Fu; D. D. Keiser, Jr.; Y. H. Sohn; A. Paz y Puente

    2014-06-01

    Zirconium has recently garnered attention for use as a diffusion barrier between UMo nuclear fuels and Al cladding alloys. Interdiffusion and reactions between Zr and Al, Al-2 wt.% Si, Al-5 wt.% Si or AA6061 were investigated using solid-to-solid diffusion couples annealed in the temperature range of 425 degrees to 625 degrees C. In the binary Al and Zr system, the Al3Zr and Al2Zr phases were identified, and the activation energy for the growth of the Al3Zr phase was determined to be 347 kJ/mol. Negligible diffusional interactions were observed for diffusion couples between Zr vs. Al-2 wt.% Si, Al-5 wt.% Si and AA6061 annealed at or below 475 degrees C. In diffusion couples with the binary AlSi alloys at 560 degrees C, a significant variation in the development of the phase constituents was observed including the thick t1 (Al5SiZr2) with Si content up to 12 at.%, and thin layers of (Si,Al)2Zr, (Al,Si)3Zr, Al3SiZr2 and Al2Zr phases. The use of AA6061 as a terminal alloy resulted in the development of both T1 (Al5SiZr2) and (Al,Si)3Zr phases with a very thin layer of (Al,Si)2Zr. At 560 degrees C, with increasing Si content in the AlSi alloy, an increase in the overall rate of diffusional interaction was observed; however, the diffusional interaction of Zr in contact with multicomponent AA6061 with 0.40.8 wt.% Si was most rapid.

  9. Thermally-driven H interaction with HfO{sub 2} films deposited on Ge(100) and Si(100)

    SciTech Connect (OSTI)

    Soares, G. V. Feij, T. O.; Baumvol, I. J. R.; Aguzzoli, C.; Krug, C.; Radtke, C.

    2014-01-27

    In the present work, we investigated the thermally-driven H incorporation in HfO{sub 2} films deposited on Si and Ge substrates. Two regimes for deuterium (D) uptake were identified, attributed to D bonded near the HfO{sub 2}/substrate interface region (at 300?C) and through the whole HfO{sub 2} layer (400600?C). Films deposited on Si presented higher D amounts for all investigated temperatures, as well as, a higher resistance for D desorption. Moreover, HfO{sub 2} films underwent structural changes during annealings, influencing D incorporation. The semiconductor substrate plays a key role in this process.

  10. Transformation of amorphous TiO2 to a hydronium oxofluorotitanate and applications as an HF sensor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Appelhans, Leah N.; Finnegan, Patrick S.; Massey, Lee T.; Luk, Ting S.; Rodriguez, Mark A.; Brumbach, Michael T.; McKenzie, Bonnie; Craven, Julia M.

    2015-12-24

    We examined amorphous titania thin films for use as the active material in a polarimetry based HF sensor. The amorphous titania films were found to be sensitive to vapor phase HF and the reaction product was identified as a hydronium oxofluorotitanate phase, which has previously only been synthesized in aqueous solution. The extent of reaction varied both with vapor phase HF concentration, relative humidity, and the exposure time. HF concentrations as low as 1 ppm could be detected for exposure times of 120 h.

  11. Transformation of amorphous TiO2 to a hydronium oxofluorotitanate and applications as an HF sensor

    SciTech Connect (OSTI)

    Appelhans, Leah N.; Finnegan, Patrick S.; Massey, Lee T.; Luk, Ting S.; Rodriguez, Mark A.; Brumbach, Michael T.; McKenzie, Bonnie; Craven, Julia M.

    2015-12-24

    We examined amorphous titania thin films for use as the active material in a polarimetry based HF sensor. The amorphous titania films were found to be sensitive to vapor phase HF and the reaction product was identified as a hydronium oxofluorotitanate phase, which has previously only been synthesized in aqueous solution. The extent of reaction varied both with vapor phase HF concentration, relative humidity, and the exposure time. HF concentrations as low as 1 ppm could be detected for exposure times of 120 h.

  12. Pressure and tension effects on mechanical properties of ZrAl{sub 2}

    SciTech Connect (OSTI)

    Zhang, Pinliang; Tang, Xiuzhang; Meng, Fanchen; Gong, Zizheng; Ji, Guangfu; Yang, Jinke

    2014-11-15

    Structural, elastic, thermodynamic of ZrAl{sub 2} under pressure, ideal strength and deformation mode under tension are investigated by the first-principles method. The calculated structural parameters at zero pressure are in consistent with experiments. Under pressure, elastic constants and their pressure dependence are obtained using the static finite strain technique. ZrAl{sub 2} exhibits lower elastic anisotropy. The linear thermal expansion coefficient shows greater effects of temperature at lower pressure. The ideal tensile have been investigated by stress–strain calculations. Finally, the microscopic mechanism that determines the structural stability is studied using the results of electronic structure calculations. We propose that the weakening of Zr-Zr leads to the significant change of stress–strain curve at strain ∼0.27, and the breaking of Zr{sub 2}-Zr{sub 3} leads to the structural instability of ZrAl{sub 2} under large tensile strains.

  13. Crystallization of Zr2PdxCu(1-x) and Zr2NixCu(1-x) Metallic Glass

    SciTech Connect (OSTI)

    Min Xu

    2008-08-18

    One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction {HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} metallic glass have been explored. All Zr{sub 2}Pd{sub x}Cu{sub (1-x)} compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr{sub 2}Pd{sub x}Cu{sub (1·x)} system. Meta-stable C16 phase is competitive with C11b phase at x = 0.5, which is dominated by electronic structure rather than

  14. Lifetime measurements of yrast states in {sup 162}Yb and {sup 166}Hf

    SciTech Connect (OSTI)

    McCutchan, E.A.; Casten, R.F.; Ai, H.; Amro, H.; Heinz, A.; Meyer, D.A.; Plettner, C.; Qian, J.; Ressler, J.J.; Werner, V.; Williams, E.; Winkler, R.; Zamfir, N.V.; Babilon, M.; Brenner, D.S.; Guerdal, G.; Hughes, R.O.; Thomas, N.J.

    2006-03-15

    Lifetime measurements of yrast levels in {sup 162}Yb and {sup 166}Hf were performed using the recoil distance Doppler-shift method in coincidence mode. Excited states in {sup 162}Yb and {sup 166}Hf were populated via the reactions {sup 116}Cd({sup 50}Ti, 4n) and {sup 122}Sn({sup 48}Ti, 4n), respectively. The resulting B(E2) values are compared with the X(5) critical point model predictions and interacting boson approximation (IBA) model calculations. The X(5) model provides a reasonable description of the yrast B(E2) values in {sup 166}Hf, whereas the IBA fails to reproduce the transition strengths from the higher spin levels. In {sup 162}Yb, some transitions agree with the X(5) predictions while others are more consistent with the predictions of the IBA or a deformed symmetric rotor.

  15. Fuel-cladding interaction layers in irradiated U-ZR and U-PU-ZR fuel elements.

    SciTech Connect (OSTI)

    Keiser, D. D.

    2006-01-23

    Argonne National Laboratory is developing an electrometallurgical treatment for spent nuclear fuels. The initial demonstration of this process is being conducted on U-Zr and U-Pu-Zr alloy fuel elements irradiated in the Experimental Breeder Reactor-II (EBR-II). The electrometallurgical treatment process extracts usable uranium from irradiated fuel elements and places residual fission products, actinides, process Zr, and cladding hulls (small segments of tubing) into two waste forms--a ceramic and a metal alloy. The metal waste form will contain the cladding hulls, Zr, and noble metal fission products, and it will be disposed of in a geologic repository. As a result, the expected composition of the waste form will need to be well understood. This report deals with the condition of the cladding, which will make up a large fraction of the metal waste form, after irradiation in EBR-II and before insertion into the electrorefiner. Specifically, it looks at layers that can be found on the inner surface of the cladding due to in-reactor interactions between the alloy fuel and the stainless steel cladding that occurs after the fuel has swelled and contacted the cladding. Many detailed examinations of fuel elements irradiated in EBR-II have been completed and are discussed in the context of interaction layer formation in irradiated cladding. The composition and thickness of the developed interaction layers are identified, along with the irradiation conditions, cladding type, and axial location on fuel elements where the thickest interaction layers can be expected to develop. It has been found that the largest interaction zones are observed at combined high power and high temperature regions of fuel elements and for fuel elements with U-Pu-Zr alloy fuel and D9 stainless steel cladding. The most prevalent, non-cladding constituent observed in the developed interaction layers are the lanthanide fission products.

  16. Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line

    SciTech Connect (OSTI)

    Ma Wenchao

    2012-10-20

    Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

  17. A survey of plant practices and experience in HF alkylation units

    SciTech Connect (OSTI)

    Dobis, J.D.; Clarida, D.R.; Richert, J.P.

    1994-12-31

    The T-8-20 Task Group conducted a survey of plant practices and of the performance of materials of construction in HF alkylation units. A primary goal of the survey was to expand the limited body of information on alternative alloy performance in HF alkylation units and to better define the susceptibility of steel to hydrogen induced cracking. Survey results indicate that although the incidence of cracking is reported to be low, hydrogen blistering is commonly found in pressure vessels. Few applications of alternative alloys were reported, but several areas of vulnerability or high corrosion rates are identified. Common design and maintenance practices are reviewed.

  18. Long-range corrected density functional theory with linearly-scaled HF exchange

    SciTech Connect (OSTI)

    Song, Jong-Won; Hirao, Kimihiko

    2015-12-31

    Long-range corrected density functional theory (LC-DFT) attracts many chemists’ attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.

  19. Using Pb-210/Ra-226 disequilibria for sablefish, Anoplopoma fimbria, age validation

    SciTech Connect (OSTI)

    Kastelle, C.R.; Kimura, D.K. ); Nevissi, A.E.; Gunderson, D.R. )

    1994-04-01

    Age determination of sablefish (Anoplopoma fimbria) is typically done by counting growth zones on the burnt cross-section of the otolith. The break-and-burn method of age determination is difficult to apply to sablefish. Therefore, we applied a relatively new method of fish age validation, using the disequilibrium of Pb-210/Ra-226 in the otoliths. This method of validation complements previous methods which used oxytetracycline (OTC) marking to validate incremental growth in sablefish otoliths. The Pb-210/Ra-226 disequilibria generally confirmed the ageing criteria used to interpret the otolith's burnt cross-section.

  20. Special Report: IG-RA-09-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    RA-09-02 Special Report: IG-RA-09-02 March 30, 2009 The Department of Energy's Acquisition Workforce and its Impact on Implementation of the American Recovery and Reinvestment Act of 2009 Signed by the President on February 17, 2009, the American Recovery and Reinvestment Act of 2009 (Recovery Act) seeks to strengthen the U.S. economy through the creation of new jobs, aiding State and local governments with budget shortfalls, and investing in the long-term health of the Nation's economic

  1. On the possibility of simultaneous emission of an autonomous cw HF-DF chemical laser in two spectral ranges

    SciTech Connect (OSTI)

    Bashkin, A S; Gurov, L V; Katorgin, B I; Petrova, S N; Polinovsky, D V

    2008-05-31

    The efficiencies of different fuel compositions used in the combustion chamber of an autonomous cw chemical HF-DF laser for obtaining high specific energy parameters during simultaneous lasing in HF and DF molecules in two spectral ranges are theoretically analysed. It is shown that mirrors with the reflectance above 99% in these spectral ranges can be manufactured in principle. (lasers)

  2. UNITED STATE% ENGINEER OFFICE I" RaCLI MANHATTAN D' ISTRICT

    Office of Legacy Management (LM)

    w-1 - ,.. P..*e ,e.arzUE.m -JuTm-&a- . . . UNITED STATE% ENGINEER OFFICE I" RaCLI MANHATTAN D' ISTRICT RLFSR TO ; I. 0. eox a ,. STATJON J N E W YORK, N. Y. tr.et h % ...

  3. Radiation damage in cubic ZrO2 and yttria-stabilized zirconia from molecular dynamics simulations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aidhy, Dilpuneet S.; Zhang, Yanwen; Weber, William J.

    2014-11-20

    Here, we perform molecular dynamics simulation on cubic ZrO2 and yttria-stabilized zirconia (YSZ) to elucidate defect cluster formation resulting from radiation damage, and evaluate the impact of Y-dopants. Interstitial clusters composed of split-interstitial building blocks, i.e., Zr-Zr or Y-Zr are formed. Moreover, oxygen vacancies control cation defect migration; in their presence, Zr interstitials aggregate to form split-interstitials whereas in their absence Zr interstitials remain immobile, as isolated single-interstitials. Y-doping prevents interstitial cluster formation due to sequestration of oxygen vacancies.

  4. Radiation damage in cubic-ZrO2 and yttria-stabilized zirconia from molecular dynamics simulations

    SciTech Connect (OSTI)

    Aidhy, Dilpuneet S; Zhang, Yanwen; Weber, William J

    2015-01-01

    We perform molecular dynamics simulation on cubic ZrO2 and yttria-stabilized zirconia (YSZ) to elucidate defect cluster formation resulting from radiation damage, and evaluate the impact of Y-dopants. Interstitial clusters composed of split-interstitial building blocks, i.e., Zr-Zr or Y-Zr are formed. Oxygen vacancies control cation defect migration; in their presence, Zr interstitials aggregate to form split-interstitials whereas in their absence Zr interstitials remain immobile, as isolated single-interstitials. Y-doping prevents interstitial cluster formation due to sequestration of oxygen vacancies.

  5. Density-functional study of the La2Zr207 (001) and (011) surfaces...

    Office of Scientific and Technical Information (OSTI)

    Language: English Subject: 30 DIRECT ENERGY CONVERSION; 36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS La2Zr207 surface Word Cloud More Like This Full ...

  6. QUANTIFYING COMPOSITIONAL HOMOGENEITY IN Pb(ZrTi)O3 USING ATOM...

    Office of Scientific and Technical Information (OSTI)

    Title: QUANTIFYING COMPOSITIONAL HOMOGENEITY IN Pb(ZrTi)O3 USING ATOM PROBE TOMOGRAPHY. Abstract not provided. Authors: Ihlefeld, Jon F. ; Kotula, Paul Gabriel ; Brennecka, ...

  7. Microstructural studies on cast Zr[sub 3]Al-3wt%Nb

    SciTech Connect (OSTI)

    Tewari, R.; Dey, G.K.; Mukhopadhyay, P.; Banerjee, S. . Metallurgy Div.)

    1994-05-01

    In the binary Zr-Al system, Zr[sub 3]Al is the intermetallic phase richest in zirconium. In view of its low absorption cross section for thermal neutrons and its good strength and corrosion resistance, Zr[sub 3]Al may have possible applications as a structural material in thermal reactors. This phase has the ordered cubic L1[sub 2] structure and forms through the peritectoid reaction: [beta]-Zr + Zr[sub 2]Al[minus] > Zr[sub 3]Al, the reaction temperature being 1,292 K. Structurally Zr[sub 3]Al is quite similar to the [alpha][sub 2] or the Ti[sub 3]Al phase (ordered hexagonal DO[sub 19] structure) in the Ti-Al system, the two structures differing only in the stacking sequence of the close packed atomic layers. But for its inherent brittleness, Ti[sub 3]Al is a promising structural material for aerospace applications. It has, however, been demonstrated that niobium additions can reduce the brittleness of this phase. Studies on the Ti[sub 3]Al-Nb system have also shown that niobium stabilizes the high temperature [beta] phase (bcc structure) which, on cooling, can decompose through various phase reactions, generating some interesting microstructures. Similar studies on the Zr[sub 3]Al-Nb system have not been reported yet. The present paper describes some microstructural observations made on a cast Zr[sub 3]Al-3wt%Nb alloy.

  8. Thermodynamic Modeling and Experimental Study of the Fe-Cr-Zr System

    SciTech Connect (OSTI)

    Yang, Ying; Tan, Lizhen; Bei, Hongbin; Busby, Jeremy T

    2013-01-01

    Wide applications of zircaloys, stainless steels and their interactions in nuclear reactors require the knowledge on phase stability and thermodynamic property of the Fe-Cr-Zr system. This knowledge is also important to develop new Zr-contained Fe-Cr ferritic steels. This work aims at developing thermodynamic models for describing phase stability and thermodynamic property of the Fe-Cr-Zr system using the Calphad approach coupled with experimental study. Thermodynamic descriptions of the Fe-Cr and Cr-Zr systems were either directly adopted or slightly modified from literature. The Fe-Zr system has been remodeled to accommodate recent ab-initio calculation of formation enthalpies of various Fe-Zr compounds. Reliable ternary experimental data and thermodynamic models were mainly available in the Zr-rich region. Therefore, selected ternary alloys located in the vicinity of the eutectic valley of (Fe,Cr,Zr) and (Fe,Cr)2Zr laves phase in the Fe-rich region have been experimentally investigated in this study. Microstructure has been examined by using scanning electron microscope, energy-dispersive Xray spectroscopy and X-ray diffraction. These experimental results, along with the literature data were then used to develop thermodynamic models for phases in the Fe-Cr-Zr system. Calculated phase equilibria and thermodynamic properties of the ternary system yield satisfactory agreements with available experimental data, which gives the confidence to use these models as building blocks for developing a Zr, Fe and Cr contained multicomponent thermodynamic database for broader applications in nuclear reactors.

  9. Current (1984) status of the study of /sup 226/Ra and /sup 228/Ra in humans at the Center for Human Radiobiology

    SciTech Connect (OSTI)

    Rundo, J.; Keane, A.T.; Lucas, H.F.; Schlenker, R.A.; Stebbings, J.H.; Stehney, A.F.

    1984-01-01

    The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to /sup 226/Ra and /sup 228/Ra. Included are 4863 dial painters (mostly women) and non-laboratory employees of the radium dial industry, 410 laboratory workers, 399 persons who received radium for supposed therapeutic effects, and 112 in other categories. Body contents of radium have been measured in 1916 of the dial workers and about one-half of the subjects in the other groups. Bone sarcomas, carcinomas of the paranasal sinuses and mastoids, and deterioration of skeletal tissue are still the only effects unequivocally attributable to internal radium. Excess leukemias have not been observed and other malignancies, if in excess, appear more likely to be related to external gamma radiation or radon than to internal radium. Positive correlations with radium burdens have been found for the incidence of benign exostoses among subjects exposed to radium before age 18 and for shortened latency of ocular cataracts. 26 references, 3 figures, 5 tables.

  10. Zr electrorefining process for the treatment of cladding hull waste in LiCl-KCl molten salts

    SciTech Connect (OSTI)

    Lee, Chang Hwa; Lee, You Lee; Jeon, Min Ku; Kang, Kweon Ho; Choi, Yong Taek; Park, Geun Il

    2013-07-01

    Zr electrorefining for the treatment of Zircaloy-4 cladding hull waste is demonstrated in LiCl-KCl-ZrCl{sub 4} molten salts. Although a Zr oxide layer thicker than 5 μm strongly inhibits the Zr dissolution process, pre-treatment processes increases the dissolution kinetics. For 10 g-scale experiments, the purities of the recovered Zr were 99.54 wt.% and 99.74 wt.% for fresh and oxidized cladding tubes, respectively, with no electrical contact issue. The optimal condition for Zr electrorefining has been found to improve the morphological feature of the recovered Zr, which reduces the salt incorporation by examining the effect of the process parameters such as the ZrCl{sub 4} concentration and the applied potential.

  11. Radiative strength functions for dipole transitions in {sup 90}Zr

    SciTech Connect (OSTI)

    Fedorets, I. D. Ratkevich, S. S.

    2013-01-15

    Partial cross sections for the (p, {gamma}) reaction on the {sup 89}Y nucleus that were measured previously at proton energies between 2.17 and 5.00 MeV and which were averaged over resonances were used to determine the absolute values and the energy distribution of the strength of dipole transitions from compound-nucleus states to low-lying levels of the {sup 90}Zr nucleus. The data obtained in this way were compared with the predictions of various models.

  12. Active eutectoid decomposition in Zr-3 wt.% Fe

    SciTech Connect (OSTI)

    Kumar, L.; Ramanujan, R.V.; Tewari, R.; Mukhopadhyay, P.; Banerjee, S.

    1999-02-19

    In the work reported here, the microstructural features associated with the active eutectoid decomposition of a near eutectoid alloy (Zr-3 wt.%Fe) on {beta} quenching were examined. The effects of aging after {beta} quenching, and of furnace cooling from the {beta} phase field, on the microstructure of the alloy were also studied. The microstructural characterization was carried out using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The room temperature mechanical properties corresponding to some of the microstructures were evaluated by mechanical testing.

  13. Atomistic Studies of Cation Transport in Tetragonal ZrO2 During Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-10-01

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is one of the major degradation mechanisms of these alloys. During corrosion the transport of oxidizing species in zirconium dioxide (ZrO2) determines the corrosion kinetics. Previously it has been argued that the outward diffusion of cation ions is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO2. The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration barriers of some defect clusters can be much lower than those of point defects. The migration of Zr interstitials at some special grain boundaries is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed.

  14. Geochemistry of Ca, Sr, Ba and Ra sulfates in some deep brines from the Palo Duro basin, Texas

    SciTech Connect (OSTI)

    Langmuir, D.; Melchior, D.

    1985-11-01

    The geochemistry of Ca, Sr, Ba and Ra sulfates in some deep brines from the Palo Duro Basin of north Texas, was studied to define geochemical controls on radionuclides such as /sup 90/Sr and /sup 226/Ra. Published solubility data for gypsum, anhydrite, celestite, barite and RaSO/sub 4/ were first reevaluated, in most cases using the ion interaction approach of Pitzer, to determine solubility products of the sulfates as a function of temperature and pressure. Ionic strengths of the brines were from 2.9 to 4.8 m, their temperatures and pressures up to 40/sup 0/C and 130 bars. Saturation indices of the sulfates were computed with the ion-interaction approach in one brine from the arkosic granite wash facies and four from the carbonate Wolfcamp Formation. All five brines are saturated with respect to gypsum, anhydrite and celestite, and three of the five with respect to barite. All are undersaturated by from 5 to 6 orders of magnitude with respect to pure RaSO/sub 4/. /sup 226/Ra concentrations in the brines, which ranged from 10/sup -11.3/ to 10/sup -12.7/ m, are not controlled by RaSO/sub 4/ solubility or adsorption, but possibly by the solubility of trace Ra solid solutions in sulfates including celestite and barite.

  15. g factor of the 2{sub 1}{sup +} state of {sup 172}Hf

    SciTech Connect (OSTI)

    Berant, Z.; Wolf, A.; Oster, E.; Casperson, R. J.; Werner, V.; Heinz, A.; Casten, R. F.; Terry, J. R.; Winkler, R.; Williams, E.; Qian, J.; Schmidt, A.; Smith, M. K.; Ahn, T.; Gurdal, G.; McCutchan, E. A.; Brenner, D. S.; Beausang, C. W.; Regan, P. H.; Ross, T.

    2009-11-15

    The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +})=0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

  16. g-factor of the 2{sup+}{sub{1} state of {sup179}Hf.

    SciTech Connect (OSTI)

    Berant, Z.; Oster, E.; Wolf, A.; Casperson, R. J.; Werner, V.; McCutchan, E. A.

    2009-01-01

    The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +}) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

  17. The Hydrogen Energy California Project, OAS-RA-13-22

    Energy Savers [EERE]

    U.S. Department of Energy Office of Inspector General Office of Audits and Inspections Audit Report The Hydrogen Energy California Project OAS-RA-13-22 June 2013 Department of Energy Washington, DC 20585 June 6, 2013 MEMORANDUM FOR THE ACTING DEPUTYASSISTANT SECRETARY FOR CLEAN COAL DIRECTOR FOR POLICY, OFFICE OF ACQUISITION AND PROJECT MANAGEMENT FROM: David Sedillo Director, Western Audits Division Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Hydrogen Energy

  18. The Department of Energy's Solid-State Lighting Program, OAS-RA-L-13-03

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Solid- State Lighting Program OAS-RA-L-13-03 February 2013 Department of Energy Washington, DC 20585 February 28, 2013 MEMORANDUM FOR THE DIRECTOR, NATIONAL ENERGY TECHNOLOGY LABORATORY FROM: Jack Rouch, Director Central Audits Division Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Department of Energy's Solid-State Lighting Program" BACKGROUND The Department of Energy's (Department) Office of Energy Efficiency and Renewable Energy established the Solid-State

  19. Audit Report: OAS-RA-10-08 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Audit Report: OAS-RA-10-08 April 27, 2010 The Department of Energy's Program to Assist Federal Buyers in the Purchasing of Energy Efficient Products The American Recovery and Reinvestment Act of 2009 (Recovery Act) established a series of energy-related goals, one of which was to make Federal facilities more energy efficient. The Department of Energy (Department) plays an integral part in this process. The Department's Federal Energy Management Program (FEMP), established in 1973, helps

  20. Audit Report: OAS-RA-11-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Audit Report: OAS-RA-11-03 November 30, 2010 The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act for the City of Phoenix - Agreed-Upon Procedures The attached report presents the results of an agreed-upon procedures review of the Department of Energy's (Department) Weatherization Assistance Program in the City of Phoenix, Arizona, under the American Recovery and Reinvestment Act of 2009 (Recovery Act). The Office of Inspector General

  1. Audit Report: OAS-RA-11-10 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 Audit Report: OAS-RA-11-10 July 28, 2011 The Department of Energy's American Recovery and Reinvestment Act - California State Energy Program The Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) provides grants to states, territories and the District of Columbia (states) through the State Energy Program (SEP). Federal funding, based on a grant formula that considers the population and energy consumption in each state, amounted to $25 million for Fiscal Year (FY)

  2. Audit Report: OAS-RA-12-02 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2-02 Audit Report: OAS-RA-12-02 November 9, 2011 The State of Nevada's Implementation of the Energy Efficiency and Conservation Block Grant Program Under the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Department of Energy (Department) received $3.2 billion to fund, for the first time, the Energy Efficiency and Conservation Block Grant Program (EECBG Program). The EECBG Program provides grants to U.S. local governments, states, territories and Indian tribes to fund

  3. Audit Report: OAS-RA-L-11-11 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Audit Report: OAS-RA-L-11-11 September 23, 2011 The Department of Energy's Energy Efficiency and Conservation Block Grant Program Funded under the American Recovery and Reinvestment Act for the State of Pennsylvania Under the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Department of Energy's (Department) Energy Efficiency and Conservation Block Grant Program (Program) received $3.2 billion in funding to help U.S. cities, counties and states to develop, promote, implement

  4. Examination Report: OAS-RA-11-18 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Examination Report: OAS-RA-11-18 September 29, 2011 Community Action Partnership of the Greater Dayton Area - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 Under the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Department of Energy's (Department) Weatherization Assistance Program (Weatherization Program) received $5 billion to increase the energy efficiency of dwellings owned or occupied by low-income persons.

  5. Examination Report: OAS-RA-11-19 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    9 Examination Report: OAS-RA-11-19 September 29, 2011 Cuyahoga County of Ohio Department of Development - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 Under the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Department of Energy's (Department) Weatherization Assistance Program (Weatherization Program) received $5 billion to increase the energy efficiency of dwellings owned or occupied by low-income persons.

  6. Examination Report: OAS-RA-11-20 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 Examination Report: OAS-RA-11-20 September 30, 2011 People's Equal Action and Community Effort, Inc. -Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 The attached report presents the results of an examination of the People's Equal Action and Community Effort, Inc. (PEACE), Weatherization Assistance Program (Weatherization Program) under the American Recovery and Reinvestment Act of 2009 (Recovery Act). The Office of Inspector General (OIG)

  7. Examination Report: OAS-RA-13-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Examination Report: OAS-RA-13-03 October 17, 2012 Community Action Partnership of Orange County - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Weatherization Assistance Program (Weatherization Program) received $5 billion to reduce energy consumption for low-income households through energy efficient upgrades. The State of California received $186 million

  8. Examination Report: OAS-RA-13-11 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 Examination Report: OAS-RA-13-11 February 19, 2013 Fresno County Economic Opportunities Commission Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act) the Weatherization Assistance Program (Weatherization Program) received $5 billion to reduce energy consumption for low-income households through energy efficient upgrades. The State of California received $186 million

  9. Examination Report: OAS-RA-13-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Examination Report: OAS-RA-13-12 February 19, 2013 City of Los Angeles - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Energy Efficiency and Conservation Block Grant (EECBG) Program received $3.2 billion to develop, promote, implement and manage energy efficiency and conservation projects and programs designed to reduce fossil fuel

  10. Examination Report: OAS-RA-13-14 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Examination Report: OAS-RA-13-14 February 28, 2013 Connecticut Department of Energy and Environmental Protection Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Energy Efficiency and Conservation Block Grant (EECBG) Program received $3.2 billion to develop, promote, implement and manage energy efficiency and conservation projects and

  11. Management Alert: OAS-RA-11-16 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1-16 Management Alert: OAS-RA-11-16 September 1, 2011 The Status of Energy Efficiency and Conservation Block Grant Recipients' Obligations Under the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Department of Energy (Department) Energy Efficiency and Conservation Block Grant (EECBG) Program received $3.2 billion to improve energy efficiency and reduce energy use and fossil fuel emission. EECBG agreements have a maximum performance period of 36 months and, in support of the

  12. Special Report: OAS-RA-13-10 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    13-10 Special Report: OAS-RA-13-10 February 8, 2013 The Department of Energy's Management of the Award of a $150 Million Recovery Act Grant to LG Chem Michigan Inc The Department of Energy's Vehicle Technologies Program was established to develop and deploy efficient and environmentally friendly highway transportation technologies to reduce the Nation's dependence on foreign oil and provide greater energy security. The Vehicle Technologies Program received $2.4 billion under the American

  13. Microsoft PowerPoint - P&RA CoP EPA optimization Biggs final 111215

    Office of Environmental Management (EM)

    Implementing Optimization in the Superfund Program __________________________________________________ For the Interagency Performance and Risk Assessment Community of Practice (P&RA CoP) November 12, 2015 Kirby Biggs National Optimization Program Coordinator Technology Integration and Information Branch Office of Superfund Remediation and Technology Integration Washington DC 20460 biggs.kirby@epa.gov . 703-823-3081 . www.cluin.org/optimization (Cleanup Horizon: 2004 - 2033) Source:

  14. Examination Report: OAS-RA-13-17 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Examination Report: OAS-RA-13-17 March 28, 2013 Community Action Partnership of San Bernardino County - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 As part of the American Recovery and Reinvestment Act of 2009 (Recovery Act), the Weatherization Assistance Program (Weatherization Program) received $5 billion to reduce energy consumption for low-income households through energy efficient upgrades. The State of California received $186

  15. Audit Report: OAS-RA-09-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    09-03 Audit Report: OAS-RA-09-03 May 27, 2009 Department of Energy Efforts to Manage Information Technology Resources in an Energy-Efficient and Environmentally Responsible Manner Conservation as critical to the Nation's economic vitality; its goal of reducing dependence on foreign energy sources; and, related efforts to improve the environment. The Act highlights the significant use of various forms of energy in the Federal sector and promotes efforts to improve the energy efficiency of Federal

  16. Audit Report: OAS-RA-11-04 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-11-04 February 1, 2011 The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act for the Capital Area Community Action Agency - Agreed-Upon Procedures The attached report presents the results of an agreed-upon procedures review of the Department of Energy's (Department) Weatherization Assistance Program for the Capital Area Community Action Agency, located in Tallahassee, Florida under the American Recovery and

  17. Audit Report: OAS-RA-11-07 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    7 Audit Report: OAS-RA-11-07 June 6, 2011 The Department of Energy's Weatherization Assistance Program Funded under the American Recovery and Reinvestment Act for the State of Wisconsin The Department of Energy's Weatherization Assistance Program (Weatherization Program) received $5 billion under the American Recovery and Reinvestment Act of 2009 (Recovery Act) to improve the energy efficiency of homes, multi-family rental units and mobile homes owned or occupied by low-income persons.

  18. Audit Report: OAS-RA-11-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-11-12 August 22, 2011 The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Missouri The Department of Energy's (Department) Weatherization Assistance Program (Weatherization Program) received $5 billion under the American Recovery and Reinvestment Act of 2009 to improve the energy efficiency of the homes of low-income individuals, of which the State of Missouri received a 3-year Weatherization Program

  19. Audit Report: OAS-RA-11-14 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    4 Audit Report: OAS-RA-11-14 August 25, 2011 The Department of Energy's Weatherization Assistance Program Funded under the American Recovery and Reinvestment Act for the Commonwealth of Virginia In May 2010, the Office of Inspector General (OIG) issued a Preliminary Audit Report on the effectiveness of the Commonwealth of Virginia's implementation of the American Recovery and Reinvestment Act of 2009 (Recovery Act) funded Weatherization Assistance Program (Weatherization Program). The report,

  20. Audit Report: OAS-RA-13-22 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Audit Report: OAS-RA-13-22 June 6, 2013 The Hydrogen Energy California Project Under the American Recovery and Reinvestment Act of 2009, the Department of Energy's (Department) Office of Fossil Energy received $3.4 billion to focus on the research, development and deployment of technologies to use coal more cleanly and efficiently. In September 2009, the Department approved a cooperative agreement award with a Government contribution of $308 million to Hydrogen Energy California, LLC (HECA) to

  1. Audit Report: OAS-RA-13-31 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    31 Audit Report: OAS-RA-13-31 September 27, 2013 The Department of Energy's Hydrogen and Fuel Cells Program The Department of Energy spent approximately $1 billion over the last 5 years on Hydrogen and Fuel Cells Program activities implemented through various projects at Federal laboratories, universities, non-profit institutions, Government agencies and industry participants. The Department also provided an additional $42 million in American Recovery and Reinvestment Act of 2009 funding to

  2. Audit Report: OAS-RA-L-13-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    3 Audit Report: OAS-RA-L-13-03 February 28, 2013 The Department of Energy's Solid-State Lighting Program The Department of Energy's (Department) Office of Energy Efficiency and Renewable Energy established the Solid-State Lighting Program to advance the development and market introduction of energy-efficient white-light sources for general illumination. The American Recovery and Reinvestment Act of 2009 appropriated more than $41 million to accelerate solid-state lighting research and

  3. The Department of Energy's Transportation Electrification Program, 0AS-RA-12-11

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Transportation Electrification Program OAS-RA-12-11 May 2012 Department of Energy Washington, DC 20585 May 10, 2012 MEMORANDUM FOR THE DEPUTY ASSISTANT SECRETARY FOR ENERGY EFFICIENCY FROM: Joanne Hill, Director Central Audits Division Office of Inspector General SUBJECT: INFORMATION: Special Report on "The Department of Energy's Transportation Electrification Program" INTRODUCTION The Department of Energy established the Transportation Electrification Program (Program) to demonstrate

  4. Mode specificity in the HF + OH → F + H{sub 2}O reaction

    SciTech Connect (OSTI)

    Song, Hongwei; Li, Jun; Guo, Hua

    2014-10-28

    Full-dimensional quantum dynamics and quasi-classical trajectory calculations are reported for the title reaction on a recently constructed ab initio based global potential energy surface. Strong mode specificity was found, consistent with the prediction of the sudden vector projection model. Specifically, the HF vibration strongly promotes the reaction while the OH vibration has little effect. Rotational excitations of both reactants slightly enhance the reaction.

  5. In situ study of e-beam Al and Hf metal deposition on native oxide InP (100)

    SciTech Connect (OSTI)

    Dong, H.; KC, Santosh; Azcatl, A.; Cabrera, W.; Qin, X.; Brennan, B.; Cho, K.; Wallace, R. M.; Zhernokletov, D.

    2013-11-28

    The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The In-oxides are completely scavenged forming In-In/In-(Al/Hf) bonding after Al and Hf metal deposition. The P-oxide concentration is significantly decreased, and the P-oxide chemical states have been changed to more P-rich oxides upon metal deposition. Indium diffusion through these metals before and after annealing at 250 °C has also been characterized. First principles calculation shows that In has lower surface formation energy compared with Al and Hf metals, which is consistent with the observed indium diffusion behavior.

  6. Electronic properties of InP (001)/HfO{sub 2} (001) interface: Band offsets and oxygen dependence

    SciTech Connect (OSTI)

    KC, Santosh; Dong, Hong; Longo, Roberto C.; Xiong, Ka; Wang, Weichao; Wallace, Robert M.; Cho, Kyeongjae

    2014-01-14

    Using ab-initio methods, atomic structures and electronic properties of InP (001)/HfO{sub 2} (001) interface are studied within the framework of density functional theory. We examine the InP/HfO{sub 2} model interface electronic structures under varying oxidation conditions. The effects of indium and phosphorous concentrations on interfacial bonding, defect states, band offsets, and the thermodynamic stability at the interface are also investigated. The origin of interfacial gap states in InP (001)/HfO{sub 2} (001) interface are proposed, mainly from the P-rich oxides, which is validated by our experimental work. This highlights the importance of surface passivation prior to high-κ deposition based on the in situ spectroscopic results of atomic layer deposition of HfO{sub 2} on InP.

  7. Upper atmospheric effects of the hf active auroral research program ionospheric research instrument (HAARP IRI)

    SciTech Connect (OSTI)

    Eccles, V.; Armstrong, R.

    1993-05-01

    The earth's ozone layer occurs in the stratosphere, primarily between 10 and 30 miles altitude. The amount of ozone, O3, present is the result of a balance between production and destruction processes. Experiments have shown that natural processes such as auroras create molecules that destroy O. One family of such molecules is called odd nitrogen of which nitric oxide (NO) is an example. Because the HAARP (HF Active Auroral Research Program) facility is designed to mimic and investigate certain natural processes, a study of possible effects of HAARP on the ozone layer was conducted. The study used a detailed model of the thermal and chemical effects of the high power HF beam, which interacts with free electrons in the upper atmosphere above 50 miles altitude. It was found only a small fraction of the beam energy goes into the production of odd nitrogen molecules, whereas odd nitrogen is efficiently produced by auroras. Since the total energy emitted by HAARP in the year is some 200,000 times less than the energy deposited in the upper atmosphere by auroras, the study demonstrates that HAARP HF beam experiments will cause no measurable depletion of the earth's ozone layer.... Ozone, Ozone depletion, Ozone layer, Odd nitrogen, Nitric oxide, HAARP Emitter characteristics.

  8. Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

    SciTech Connect (OSTI)

    Zhao, Xin; Ke, Liqin; Nguyen, Manh Cuong; Wang, Cai -Zhuang; Ho, Kai -Ming

    2015-06-23

    The structures and magnetic properties of Co-Zr-B alloys near the composition of Co5Zr with B at. % ≤6% were studied using adaptive genetic algorithm and first-principles calculations. The energy and magnetic moment contour maps as a function of chemical composition were constructed for the Co-Zr-B magnet alloys through extensive structure searches and calculations. We found that Co-Zr-B system exhibits the same structure motif as the “Co11Zr2” polymorphs, and such motif plays a key role in achieving strong magnetic anisotropy. Boron atoms were found to be able to substitute cobalt atoms or occupy the “interruption” sites. First-principles calculations showed that the magnetocrystalline anisotropy energies of the boron-doped alloys are close to that of the high-temperature rhombohedral Co5Zr phase and larger than that of the low-temperature Co5.25Zr phase. As a result, our calculations provide useful guidelines for further experimental optimization of the magnetic performances of these alloys.

  9. Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhao, Xin; Ke, Liqin; Nguyen, Manh Cuong; Wang, Cai -Zhuang; Ho, Kai -Ming

    2015-06-23

    The structures and magnetic properties of Co-Zr-B alloys near the composition of Co5Zr with B at. % ≤6% were studied using adaptive genetic algorithm and first-principles calculations. The energy and magnetic moment contour maps as a function of chemical composition were constructed for the Co-Zr-B magnet alloys through extensive structure searches and calculations. We found that Co-Zr-B system exhibits the same structure motif as the “Co11Zr2” polymorphs, and such motif plays a key role in achieving strong magnetic anisotropy. Boron atoms were found to be able to substitute cobalt atoms or occupy the “interruption” sites. First-principles calculations showed that themore » magnetocrystalline anisotropy energies of the boron-doped alloys are close to that of the high-temperature rhombohedral Co5Zr phase and larger than that of the low-temperature Co5.25Zr phase. As a result, our calculations provide useful guidelines for further experimental optimization of the magnetic performances of these alloys.« less

  10. Plant cyclopeptide RA-V kills human breast cancer cells by inducing mitochondria-mediated apoptosis through blocking PDK1AKT interaction

    SciTech Connect (OSTI)

    Fang, Xian-Ying; Chen, Wei; Fan, Jun-Ting; Song, Ran; Wang, Lu; Gu, Yan-Hong; Zeng, Guang-Zhi; Shen, Yan; Wu, Xue-Feng; Tan, Ning-Hua; Xu, Qiang; Sun, Yang

    2013-02-15

    In the present paper, we examined the effects of a natural cyclopeptide RA-V on human breast cancer cells and the underlying mechanisms. RA-V significantly inhibited the growth of human breast cancer MCF-7, MDA-MB-231 cells and murine breast cancer 4T1 cells. In addition, RA-V triggered mitochondrial apoptotic pathway which was indicated by the loss of mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase cascade. Further study showed that RA-V dramatically inhibited phosphorylation of AKT and 3-phosphoinositide dependent protein kinase 1 (PDK1) in MCF-7 cells. Moreover, RA-V disrupted the interaction between PDK1 and AKT in MCF-7 cells. Furthermore, RA-V-induced apoptosis could be enhanced by phosphatidylinositol 3-kinase inhibitor or attenuated by over-expression of AKT in all the three kinds of breast cancer cells. Taken together, this study shows that RA-V, which can induce mitochondria-mediated apoptosis, exerts strong anti-tumor activity against human breast cancer. The underlying anti-cancer mechanism of RA-V is related to the blockage of the interaction between PDK1 and AKT. - Highlights: ? Plant cyclopeptide RA-V kills human breast cancer cells. ? RA-V triggered mitochondrial apoptotic pathway in human breast cancer cells. ? RA-V inhibited phosphorylation of AKT and PDK1 in breast cancer MCF-7 cells. ? Its mechanism is related to the blockage of the interaction between PDK1 and AKT.

  11. Radiation Stability of Mo2Zr Phase as an Interaction Product in U-10M0/Zr/Al 6061 Monolithic Fuel Plate

    SciTech Connect (OSTI)

    Jian Gan; Brandon D. Miller; Dennis D. Keiser; Daniel M. Wachs; W. Sprowes; Y. H. Sohn; M. Kirk

    2015-04-01

    Abstract Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (< 20% U-235 enrichment). These fuel plates contain a Zr diffusion barrier between the U-10Mo fuel and Al-6061 cladding that suppresses the interaction between the two that is known to be problematic under irradiation. However, the Zr also interacts with the U-10Mo and Al-6061 cladding during fuel fabrication to produce a variety of interaction phases. The results from recent post-irradiation-examination (PIE) of the irradiated monolithic fuel plates suggested that the microstructural development of the U-10Mo/Zr interaction phases under irradiation may have an impact on fuel performance. The Mo2Zr phase has been identified as a major interaction product at the interface of U-10Mo and Zr. TEM in-situ irradiation with 500 keV Kr ions at 200 ?C temperature to 2?1016 ions/cm2 was carried out to investigate its radiation stability. The Mo2Zr undergoes a radiation-induced structural change, from a large cubic (cF24, a0 = 0.7588 nm) to a small bcc cubic (cI2, a0 = 0.3185 nm), along with an estimated 11.3% volume contraction without changing its composition. The Mo2Zr phase demonstrated exceptional radiation tolerance with the development of dislocation showing no evidence of bubble formation. The irradiation to the same ion dose with the reduced ion energy at 250 keV reveals a high concentration of small bubbles (< 2 nm) as a result of increased Kr ion retention in the sample. .

  12. Dissolution process for ZrO.sub.2 -UO.sub.2 -CaO fuels

    DOE Patents [OSTI]

    Paige, Bernice E.

    1976-06-22

    The present invention provides an improved dissolution process for ZrO.sub.2 -UO.sub.2 -CaO-type pressurized water reactor fuels. The zirconium cladding is dissolved with hydrofluoric acid, immersing the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers in the resulting zirconium-dissolver-product in the dissolver vessel, and nitric acid is added to the dissolver vessel to facilitate dissolution of the uranium from the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers.

  13. Quantitative phase analysis of Mg:ZrO{sub 2} nanoparticles by Rietveld refinement method

    SciTech Connect (OSTI)

    Balaji, V. Senthilkumaran, S. Thangadurai, P.

    2014-04-24

    To quantify the structural phases of nanocrystalline ZrO{sub 2} doped with Mg ions of varying concentrations (3, 5, 10, 15 and 20%) and annealed at different temperatures. Magnesia doped zirconia was prepared by chemical co-precipitation method and annealed up to 1000°C. The monoclinic and tetragonal phases present in Mg:ZrO{sub 2} were quantified using Rietveld refinement analysis of the X-ray diffraction data and compared with the Direct method based on peak intensity calculations. Tetragonal phase was dominant in the 600°C annealed Mg:ZrO{sub 2} for all Mg concentrations.

  14. Performance enhancement of GaN metalsemiconductormetal ultraviolet photodetectors by insertion of ultrathin interfacial HfO{sub 2} layer

    SciTech Connect (OSTI)

    Kumar, Manoj E-mail: aokyay@ee.bilkent.edu.tr; Tekcan, Burak; Okyay, Ali Kemal E-mail: aokyay@ee.bilkent.edu.tr

    2015-03-15

    The authors demonstrate improved device performance of GaN metalsemiconductormetal ultraviolet (UV) photodetectors (PDs) by ultrathin HfO{sub 2} (UT-HfO{sub 2}) layer on GaN. The UT-HfO{sub 2} interfacial layer is grown by atomic layer deposition. The dark current of the PDs with UT-HfO{sub 2} is significantly reduced by more than two orders of magnitude compared to those without HfO{sub 2} insertion. The photoresponsivity at 360?nm is as high as 1.42 A/W biased at 5 V. An excellent improvement in the performance of the devices is ascribed to allowed electron injection through UT-HfO{sub 2} on GaN interface under UV illumination, resulting in the photocurrent gain with fast response time.

  15. Pygmy dipole resonance and dipole polarizability in {sup 90}Zr

    SciTech Connect (OSTI)

    Iwamoto, C.; Tamii, A.; Shima, T.; Hashimoto, T.; Suzuki, T.; Fujita, H.; Hatanaka, K.; Utsunomiya, H.; Akimune, H.; Yamagata, T.; Okamoto, A.; Kondo, T.; Nakada, H.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Shimbara, Y.; Nagashima, M.; Sakuda, M.; Mori, T.; and others

    2014-05-02

    Electric dipole (E1) reduced transition probability B(E1) of {sup 90}Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability ?{sub D} which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.

  16. The comparative kinetics of Ca, Sr, And Ra in a freshwater turtle, Trachemys scripta

    SciTech Connect (OSTI)

    Hinton, T.G.

    1989-01-01

    The accumulation of {sup 45}Ca, {sup 47}Ca, {sup 88}Sr, and {sup 226}Ra was studied in the yellow-bellied slider, a common freshwater turtle of the Southeastern US. The author was particularly interested in testing the hypothesis of competitive inhibition, a concept whereby decreasing the intake of a stable dietary element increases the absorption and retention of chemically similar radionuclides. He established four specific hypotheses and examined the processes of absorption and elimination as a function of stable dietary calcium (2 and 20 mg g{sup {minus}1}), season (summer, fall, winter and spring), and age and sex of the animals (hatchlings, juveniles, adult males, adult females, and gravid females). Turtles were gavaged with radionuclides and the gamma-emitting isotopes were detected during serial whole-body counts performed on the live animals for up to 480 d. The analysis of the beta-emitting {sup 45}Ca was accomplished by chemical separation procedures. Data were fit to a two-component exponential retention model by nonlinear regression. The 10-fold reduction in dietary Ca did not affect the elimination rate constants, and increased the assimilation of Sr and Ra only within juveniles. For all animals the absorption of Ca was significantly greater than Sr, and likewise, Sr was greater than Ra. Mean absorptions were generally higher than values reported for other organisms. Unlike many other organisms, absorption rates did not decline at maturity. He suspects that high Ca demands in constructing and maintaining the massive shell, necessitated by the turtle's survival strategy, may contribute to the high absorption, as well as the lack of a decline at maturity. Elimination rate constants were greatest in the summer and declined to levels that were generally not distinguishable from zero in the spring, winter, and fall seasons.

  17. Special Report: OAS-RA-12-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2-03 Special Report: OAS-RA-12-03 January 18, 2012 Lessons Learned/Best Practices during the Department of Energy's Implementation of the American Recovery and Reinvestment Act of 2009 The American Recovery and Reinvestment Act of 2009 (Recovery Act) was signed into law on February 17, 2009 as a way to jumpstart the U.S. economy, create or save millions of jobs, spur technological advances in science and health, and invest in the Nation's energy future. As part of the Recovery Act, the

  18. Low-load indentation behavior of HfN thin films deposited by reactive rf sputtering

    SciTech Connect (OSTI)

    Nowak, R.; Li, C.L.; Maruno, S.

    1997-01-01

    Deformation of HfN thin films deposited by reactive sputtering method on silicon and alumina substrates has been investigated using depth-sensing indentation. The experiments performed in a low load range (2{endash}50 mN) revealed that the even extremely shallow indentations were affected by elastic/plastic response of the substrate. The analysis of the shape of the indentation load-depth hysteresis loops and of conventional hardness data was supplemented by considerations based on the recently proposed energy principle of indentation. {copyright} {ital 1997 Materials Research Society.}

  19. HF-based etching processes for improving laser damage resistance of fused silica optical surfaces

    SciTech Connect (OSTI)

    Suratwala, T I; Miller, P E; Bude, J D; Steele, R A; Shen, N; Monticelli, M V; Feit, M D; Laurence, T A; Norton, M A; Carr, C W; Wong, L L

    2010-02-23

    The effect of various HF-based etching processes on the laser damage resistance of scratched fused silica surfaces has been investigated. Conventionally polished and subsequently scratched fused silica plates were treated by submerging in various HF-based etchants (HF or NH{sub 4}F:HF at various ratios and concentrations) under different process conditions (e.g., agitation frequencies, etch times, rinse conditions, and environmental cleanliness). Subsequently, the laser damage resistance (at 351 or 355 nm) of the treated surface was measured. The laser damage resistance was found to be strongly process dependent and scaled inversely with scratch width. The etching process was optimized to remove or prevent the presence of identified precursors (chemical impurities, fracture surfaces, and silica-based redeposit) known to lead to laser damage initiation. The redeposit precursor was reduced (and hence the damage threshold was increased) by: (1) increasing the SiF{sub 6}{sup 2-} solubility through reduction in the NH4F concentration and impurity cation impurities, and (2) improving the mass transport of reaction product (SiF{sub 6}{sup 2-}) (using high frequency ultrasonic agitation and excessive spray rinsing) away from the etched surface. A 2D finite element crack-etching and rinsing mass transport model (incorporating diffusion and advection) was used to predict reaction product concentration. The predictions are consistent with the experimentally observed process trends. The laser damage thresholds also increased with etched amount (up to {approx}30 {micro}m), which has been attributed to: (1) etching through lateral cracks where there is poor acid penetration, and (2) increasing the crack opening resulting in increased mass transport rates. With the optimized etch process, laser damage resistance increased dramatically; the average threshold fluence for damage initiation for 30 {micro}m wide scratches increased from 7 to 41 J/cm{sup 2}, and the statistical

  20. Effect of the annealing temperature and ion-beam bombardment on the properties of solution-derived HfYGaO films as liquid crystal alignment layers

    SciTech Connect (OSTI)

    Park, Hong-Gyu; Lee, Yun-Gun; Jang, Sang Bok; Lee, Ju Hwan; Jeong, Hae-Chang; Seo, Dae-Shik; Oh, Byeong-Yun

    2015-11-15

    Hafnium yttrium gallium oxide (HfYGaO) films were applied to liquid crystal displays (LCDs) as liquid crystal (LC) alignment layers, replacing conventional polyimide (PI) layers. The HfYGaO alignment layers were prepared by fabricating solution-processed HfYGaO films, annealing them, and treating them with ion-beam (IB) irradiation. The authors studied the effects of annealing temperature and IB irradiation of the solution-derived HfYGaO films on the orientation of LC molecules. The LC molecules on the solution-derived HfYGaO films were homogeneously and uniformly aligned by IB irradiation, irrespective of the annealing temperature. Atomic force microscopy analyses revealed that the surface reformation of the HfYGaO films induced by IB irradiation strengthened the van der Waals force between the LC molecules and the HfYGaO films, leading to uniform LC alignment. Enhanced electro-optical characteristics were observed in the twisted-nematic (TN) LCDs based on IB-irradiated HfYGaO films compared with those of TN-LCDs based on PI layers, demonstrating the high application potential of the proposed solution-derived HfYGaO films as LC alignment layers.

  1. Analysis of the electronic structure of ZrO{sub 2} by Compton spectroscopy

    SciTech Connect (OSTI)

    Mahammad, F. M.; Mahammed, S. F.; Kumar, R.; Vijay, Y. K.; Sharma, B. K.; Sharma, G.

    2013-07-15

    The electronic structure of ZrO{sub 2} is studied using the Compton scattering technique. The first-ever Compton profile measurement on polycrystalline ZrO{sub 2} was obtained using 59.54 keV gamma-rays emanating from the {sup 241}Am radioisotope. To explain the experimental data, we compute theoretical Compton profile values using the method of linear combination of atomic orbitals in the framework of density functional theory. The correlation scheme proposed by Perdew-Burke-Ernzerhof and the exchange scheme of Becke are considered. The ionic-model-based calculations for a number of configurations, i.e., Zr{sup +x}(O{sup -x/2}){sub 2} (0 {<=} x {<=} 2), are also performed to estimate the charge transfer on compound formation, and the study supports transfer of 1.5 electrons from Zr to O atoms.

  2. Aqueous phase hydrodeoxygenation of polyols over Pd/WO3-ZrO2...

    Office of Scientific and Technical Information (OSTI)

    Aqueous phase hydrodeoxygenation of polyols over PdWO3-ZrO2: Role of Pd-WO3 interaction and hydrodeoxygenation pathway Citation Details In-Document Search This content will become ...

  3. Current-induced spin-orbit torque switching of perpendicularly magnetized Hf|CoFeB|MgO and Hf|CoFeB|TaO{sub x} structures

    SciTech Connect (OSTI)

    Akyol, Mustafa; Yu, Guoqiang; Alzate, Juan G.; Upadhyaya, Pramey; Li, Xiang; Wong, Kin L.; Khalili Amiri, Pedram; Wang, Kang L.; Ekicibil, Ahmet

    2015-04-20

    We study the effect of the oxide layer on current-induced perpendicular magnetization switching properties in Hf|CoFeB|MgO and Hf|CoFeB|TaO{sub x} tri-layers. The studied structures exhibit broken in-plane inversion symmetry due to a wedged CoFeB layer, resulting in a field-like spin-orbit torque (SOT), which can be quantified by a perpendicular (out-of-plane) effective magnetic field. A clear difference in the magnitude of this effective magnetic field (H{sub z}{sup FL}) was observed between these two structures. In particular, while the current-driven deterministic perpendicular magnetic switching was observed at zero magnetic bias field in Hf|CoFeB|MgO, an external magnetic field is necessary to switch the CoFeB layer deterministically in Hf|CoFeB|TaO{sub x}. Based on the experimental results, the SOT magnitude (H{sub z}{sup FL} per current density) in Hf|CoFeB|MgO (?14.12?Oe/10{sup 7} A cm{sup ?2}) was found to be almost 13 larger than that in Hf|CoFeB|TaO{sub x} (?1.05?Oe/10{sup 7} A cm{sup ?2}). The CoFeB thickness dependence of the magnetic switching behavior, and the resulting ?H{sub z}{sup FL} generated by in-plane currents are also investigated in this work.

  4. Evolution of ordered {omega} phases in (Zr{sub 3}Al)-Nb alloys

    SciTech Connect (OSTI)

    Tewari, R.; Mukhopadhyay, P.; Banerjee, S.; Bendersky, L.A.

    1999-03-10

    Microstructural investigations on rapidly solidified Zr{sub 3}Al based alloys (binary Zr{sub 3}Al and ternary Zr{sub 3}Al-3Nb and Zr{sub 3}Al-10Nb) have revealed some unusual phase transformation sequences. The Zr{sub 5}Al{sub 3} phase (D8{sub 8} structure) has been found to occur in both the rapidly solidified ternary alloys unlike in the rapidly solidified stoichiometric Zr{sub 3}Al alloy in which the ZrAl phase (B8{sub 2} structure) has been found to be present. The evolution of the D8{sub 8} phase, which could be regarded as one of the ordered derivatives of the {omega} phase, could be described in terms of a superimposition of replacive and displacive ordering waves in the {beta} phase. The orientation relationship between the {beta} and the D8{sub 8} phases has been established. The microstructural changes occurring in the rapidly solidified Zr{sub 3}Al-Nb alloys during aging have been examined. It has been found that on aging the D8{sub 8} phase gets transformed into the B8{sub 2} phase which, on continued aging, transforms to other metastable and equilibrium phases, depending upon the aging temperature. The observed sequence of phase transformations involving different structurally related phases has been along the direction of progressively close packed structures. The symmetry changes associated with the sequence of {omega} related transformations have been summarized in the form of a symmetry tree.

  5. Development of a new casting method to fabricate UZr alloy containing minor actinides

    SciTech Connect (OSTI)

    Jong Hwan Kim; Hoon Song; Hyung Tae Kim; Ki Hwan Kim; Chan Bock Lee; R. S. Fielding

    2014-01-01

    Metal fuel slugs of UZr alloys for a sodium-cooled fast reactor (SFR) have conventionally been fabricated using an injection casting method. However, casting alloys containing volatile radioactive constituents, such as Am, are problematic in a conventional injection casting method. As an alternative fabrication method, low pressure gravity casting has been developed. Casting soundness, microstructural characteristics, alloying composition, density, and fuel losses were evaluated for the following as-cast fuel slugs: U10 wt% Zr, U10 wt% Zr5 wt% RE, and U10 wt% Zr5 wt% RE5 wt% Mn. The U and Zr contents were uniform throughout the matrix, and impurities such as oxyen, carbon, and nitrogen satisfied the specification of total impurities less than 2,000 ppm. The appearance of the fuel slugs was generally sound, and the internal integrity was shown to be satisfactory based on gamma-ray radiography. In a volatile surrogate casting test, the UZrREMn fuel slug showed that nearly all of the manganese was retained when casting was done under an inert atmosphere.

  6. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which themore » melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.« less

  7. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    SciTech Connect (OSTI)

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which the melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.

  8. Radiation tolerant nanocrystalline ZrN films under high dose heavy-ion irradiations

    SciTech Connect (OSTI)

    Jiao, L.; Wang, H.; Yu, K. Y.; Chen, D.; Jacob, C.; Shao, L.; Zhang, X.

    2015-04-14

    ZrN, a refractory ceramic material, finds many potential applications in advanced nuclear reactors. However, the grain size dependent radiation response in nanocrystalline (nc) ZrN under high dose heavy ion irradiation has not yet been studied to date. Here, we compare the radiation response of nc-ZrN films (with a respective average grain size of ∼9 and 31 nm) to Fe{sup 2+} ion irradiations up to a damage level of 10 displacements-per-atom (dpa). The ZrN film with the average grain size of 9 nm shows prominently enhanced radiation tolerance as evidenced by suppressed grain growth, alleviated radiation softening, as well as reduced variation in electrical resistivity. In contrast, ZrN with the larger average grain size of 31 nm shows prominent radiation softening and resistivity increase, attributed to the high density of defect cluster formed inside the grains. The influence of grain boundaries on enhanced irradiation tolerance in nc-ZrN is discussed.

  9. In situ HVEM studies of phase transformation in Zr alloys and compounds under irradiation

    SciTech Connect (OSTI)

    Motta, A.T.; Faldowski, J.A.; Howe, L.M.; Okamoto, P.R.

    1996-01-01

    The High Voltage Electron Microscope (HVEM)/Tandem facility at Argonne National Laboratory has been used to conduct detailed studies of the phase stability and microstructural evolution in zirconium alloys and compounds under ion and electron irradiation. Detailed kinetic studies of the crystalline-to-amorphous transformation of the intermetallic compounds Zr{sub 3}(Fe{sub 1-x}Ni{sub x}), Zr(Fe{sub 1-x},Cr{sub x}){sub 2}, Zr{sub 3}Fe, and Zr{sub 1.5} Nb{sub 1.5} Fe, both as second phase precipitates and in bulk form, have been performed using the in-situ capabilities of the Argonne facility, under a variety of irradiation conditions (temperature, dose rate). Results include a verification of a dose rate effect on amorphization and the influence of material variables (stoichiometry x, presence of stacking faults, crystal structure) on the critical temperature and on the critical dose for amorphization. Studies were also conducted of the microstructural evolution under irradiation of specially tailored binary and ternary model alloys. The stability of the {omega}-phase in Zr-20%Nb under electron and Ar ion irradiation was investigated as well as the {beta}-phase precipitation in Zr-2.5%Nb under Ar ion irradiation. The ensemble of these results is discussed in terms of theoretical models of amorphization and of irradiation-altered solubility.

  10. Results from ORNL Characterization of Zr02-500-AK2 - Surrogate TRISO Material

    SciTech Connect (OSTI)

    Hunn, John D; Kercher, Andrew K

    2005-06-01

    This document is a compilation of the characterization data for the TRISO-coated surrogate particle batch designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the createion of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significanly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  11. Results from ORNL characterization of ZrO2-500-AK2 - surrogate TRISO material

    SciTech Connect (OSTI)

    Kercher, Andrew K; Hunn, John D

    2005-06-01

    This document is a compilation of the characterization data for the TRISO-coated surrogate particles designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the creation of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significantly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  12. Zr-based bulk metallic glass as a cylinder material for high pressure apparatuses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Komatsu, Kazuki; Munakata, Koji; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Yokoyama, Yoshihiko; Sugiyama, Kazumasa; Matsuda, Masaaki

    2015-05-12

    Zirconium-based bulk metallic glass (Zr-based BMG) has outstanding properties as a cylinder mate- rial for piston-cylinder high pressure apparatuses and is especially useful for neutron scattering. The piston-cylinder consisting of a Zr-based BMG cylinder with outer/inner diameters of 8.8/2.5 mm sustains pressures up to 1.81 GPa and ruptured at 2.0 GPa, with pressure values determined by the superconduct- ing temperature of lead. The neutron attenuation of Zr-based BMG is similar to that of TiZr null-scattering alloy and more transparent than that of CuBe alloy. No contamination of sharp Bragg reflections is observed in the neutron diffraction pattern for Zr-based BMG.more » The magnetic susceptibility of Zr-based BMG is similar to that of CuBe alloy; this leads to a potential application for measurements of magnetic properties under pressure.« less

  13. Local elastic modulus of RF sputtered HfO{sub 2} thin film by atomic force acoustic microscopy

    SciTech Connect (OSTI)

    Jena, S. Tokas, R. B. Sarkar, P. Thakur, S.; Sahoo, N. K.; Misal, J. S.; Rao, K. D.

    2014-04-24

    Atomic force acoustic microscopy (AFAM) is a useful nondestructive technique for measurement of local elastic modulus of materials at nano-scale spatial resolution by measuring the contact resonance spectra for higher order modes of the AFM cantilever. The elastic modulus of RF sputtered HfO{sub 2} thin film has been measured quantitatively, using reference approach in which measurements are performed on the test and reference samples. Using AFAM, the measured elastic modulus of the HfO{sub 2} thin film is 223±27 GPa, which is in agreement with the literature value of 220±40 GPa for atomic layer deposited HfO{sub 2} thin film using nanoindentation technique.

  14. Comparative Analysis Of {sup 226}Ra Soil-To-Plant Transfer In Cabbage Grown In Various Regions

    SciTech Connect (OSTI)

    Madruga, M. J.; Carvalho, F. P.; Silva, L.; Gouveia, J. [Nuclear and Technological Institute/Department of Radiological Protection and Nuclear Safety E.N. 10, 2686-953 Sacavem (Portugal)

    2008-08-07

    The transfer of {sup 226}Ra from soil to cabbage was compared amongst regions, namely the surroundings of Urgeirica uranium milling tailings (GE), regions with past uranium mining activities (GN1), and regions with no uranium mining activities and no uranium deposits (GN2). Results show a slight increase of the concentration ratio values at low radium concentration in soils. Statistical analysis of the mean {sup 226}Ra activity concentrations in soil and cabbage for the three regions was carried out. The comparison of {sup 226}Ra activity concentrations in soils indicated no difference (p>0.05), between GE and GN2 and significant differences (p<0.05) between GE and GN1 and between GN1 and GN2. Similar statistical results were obtained for {sup 226}Ra activity concentrations in cabbage from the same regions. It was concluded that radium Concentration Ratio (CR) for cabbage grown in the region of the main uranium milling site (GE) is of the same order of magnitude of CR in cabagge grown in background regions (GN2). However, {sup 226}Ra CR was higher in cabagge from the region with past uranium mining activities (GN1)

  15. Interplay between gadolinium dopants and oxygen vacancies in HfO{sub 2}: A density functional theory plus Hubbard U investigation

    SciTech Connect (OSTI)

    Zhang, Wei; Hou, Z. F.

    2014-03-28

    The influence of gadolinium (Gd) doping on the oxygen vacancy (V{sub O}) in monoclinic HfO{sub 2} have been studied by the first-principles calculations within the spin-polarized generalized gradient approximation plus Hubbard U approach. It is found that the Gd dopant and V{sub O} show strong attractive interaction, resulting in a cooperative effect that the substitution of Gd for Hf (Gd{sub Hf}) would increase the probability of oxygen vacancies generation and vice versa. The Gd{sub Hf} is more energetically favorable to be next to the vacancy site of a three-coordinated oxygen (O3), forming a complex defect Gd{sub Hf} + V{sub O}. A single Gd{sub Hf} acts a hole donor and passivates the defect states of V{sub O}. Our results suggest that the decrease of the V{sub O}-related defect states observed in the photoluminescence spectra of Gd-HfO{sub 2} is because Gd doping passivates the defect states of V{sub O}, rather than caused by decrease of V{sub O} concentration. Our findings would clarify the debate about the influence of Gd doping on the oxygen vacancies in HfO{sub 2}.

  16. Collaborative Physical and Biological Dosimetry Studies for Neutron Capture Therapy at the RA-1 Research Reactor Facility

    SciTech Connect (OSTI)

    David W. Nigg; Amanda E. Schwint; John K. Hartwell; Elisa M. Heber; Veronica Trivillin; Jorge Castillo; Luis Wentzeis; Patrick Sloan; Charles A. Wemple

    2004-10-01

    Initial physical dosimetry measurements have been completed using activation spectrometry and thermoluminiscent dosimeters to characterize the BNCT irradiation facility developed at the RA-1 research reactor operated by the Argentine National Atomic Energy Commission in Buenos Aires. Some biological scoping irradiations have also been completed using a small-animal (hamster) oral mucosa tumor model. Results indicate that the RA-1 neutron source produces useful dose rates but that some improvements in the initial configuration will be needed to optimize the spectrum for thermal-neutron BNCT research applications.

  17. Special features of the isospin splitting of the giant dipole resonance in the {sup 90}Zr nucleus

    SciTech Connect (OSTI)

    Varlamov, V. V. Peskov, N. N.; Stepanov, M. E.

    2009-02-15

    Data on the proton and neutron channels of the {sup 90}Zr photodisintegration were analyzed in detail, basic parameters of the isospin splitting of the giant dipole resonance in {sup 90}Zr being determined by the properties of these channels. New data concerning the cross sections for the partial photoneutron reactions {sup 90}Zr({gamma}, n){sup 89}Zr and {sup 90}Zr({gamma}, 2n){sup 88}Zr and resulting from a simultaneous correction of data from experiments performed in Livermore (USA) and Saclay (France) by using beams of quasimonoenergetic annihilation photons were invoked. Use was made of information about the positions on the energy scale of states characterized by different isospin values in the {sup 90}Zr nucleus and nuclei neighboring it, which are members of the respective isospin multiplet. New data on the parameters of the isospin splitting of the giant dipole resonance in the {sup 90}Zr nucleus were obtained on the basis of a global analysis of data on the giant-dipole-resonance states of the {sup 90}Zr nucleus, which are manifested in the respective photoneutron and photoproton cross sections and in their decay channels involving states of different isospin in neighboring nuclei.

  18. High thermal stability of La2O3 and CeO2-stabilized tetragonal ZrO2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Shichao; Xie, Hong; Lin, Yuyuan; Poeppelmeier, Kenneth R.; Li, Tao; Winans, Randall E.; Cui, Yanran; Ribeiro, Fabio H.; Canlas, Christian P.; Elam, Jeffrey W.; et al

    2016-02-15

    Catalyst support materials of tetragonal ZrO2, stabilized by either La2O3 (La2O3-ZrO2) or CeO2 (CeO2-ZrO2), were synthesized under hydrothermal conditions at 200 °C with NH4OH or tetramethylammonium hydroxide as the mineralizer. From In Situ synchrotron powder X-ray diffraction and small-angle X-ray scattering measurements, the calcined La2O3-ZrO2 and CeO2-ZrO2 supports were nonporous nanocrystallites that exhibited rectangular shapes with thermal stability up to 1000 °C in air. These supports had an average size of ~10 nm and a surface area of 59-97 m2/g. The catalysts Pt/La2O3-ZrO2 and Pt/CeO2-ZrO2 were prepared by using atomic layer deposition with varying Pt loadings from 6.3-12.4 wt %.more » Mono-dispersed Pt nanoparticles of ~3 nm were obtained for these catalysts. As a result, the incorporation of La2O3 and CeO2 into the t-ZrO2 structure did not affect the nature of the active sites for the Pt/ZrO2 catalysts for the water-gas-shift (WGS) reaction.« less

  19. Observation of the chiral magnetic effect in ZrTe₅

    SciTech Connect (OSTI)

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A.; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurement of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. Furthermore, the observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.

  20. Chiral magnetic effect in ZrTe5

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Q.; Kharzeev, D. E.; Zhang, C.; Huang, Y.; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A.; Gu, G. D.; Valla, T.

    2016-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) - a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the measurement of magneto-transport in zirconium pentatelluride, ZrTe5 that providesmore » a strong evidence for the chiral magnetic effect. Our angleresolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background. We expect that chiral magnetic effect may emerge in a wide class of materials that are near the transition between the trivial and topological insulators.« less

  1. Observation of the chiral magnetic effect in ZrTe₅

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A.; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurementmore » of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. Furthermore, the observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.« less

  2. Determination of the direct double- β -decay Q value of Zr 96 and atomic masses of Zr 90 - 92 , 94 , 96 and Mo 92 , 94 - 98 , 100

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gulyuz, K.; Ariche, J.; Bollen, G.; Bustabad, S.; Eibach, M.; Izzo, C.; Novario, S. J.; Redshaw, M.; Ringle, R.; Sandler, R.; et al

    2015-05-06

    Experimental searches for neutrinoless double-β decay offer one of the best opportunities to look for physics beyond the standard model. Detecting this decay would confirm the Majorana nature of the neutrino, and a measurement of its half-life can be used to determine the absolute neutrino mass scale. Important to both tasks is an accurate knowledge of the Q value of the double-β decay. The LEBIT Penning trap mass spectrometer was used for the first direct experimental determination of the ⁹⁶Zr double-β decay Q value: Qββ=3355.85(15) keV. This value is nearly 7 keV larger than the 2012 Atomic Mass Evaluation [M.more » Wang et al., Chin. Phys. C 36, 1603 (2012)] value and one order of magnitude more precise. The 3-σ shift is primarily due to a more accurate measurement of the ⁹⁶Zr atomic mass: m(⁹⁶Zr)=95.90827735(17) u. Using the new Q value, the 2νββ-decay matrix element, |M2ν|, is calculated. Improved determinations of the atomic masses of all other zirconium (90-92,94,96Zr) and molybdenum (92,94-98,100Mo) isotopes using both ¹²C₈ and ⁸⁷Rb as references are also reported.« less

  3. Bio-corrosion and cytotoxicity studies on novel Zr55Co30Ti15 and Cu60Zr20Ti20 metallic glasses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vincent, S.; Daiwile, A.; Devi, S. S.; Kramer, M. J.; Besser, M. F.; Murty, B. S.; Bhatt, Jatin

    2014-09-26

    Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr55Co30Ti15 and Cu60Zr20Ti20 metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hank’s balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 °C). Surface morphology of samples after bio-corrosion experiments was observed by scanning electron microscopy.more » In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.« less

  4. Infrared study on room-temperature atomic layer deposition of HfO{sub 2} using tetrakis(ethylmethylamino)hafnium and remote plasma-excited oxidizing agents

    SciTech Connect (OSTI)

    Kanomata, Kensaku [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan and Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Ohba, Hisashi; Pungboon Pansila, P.; Ahmmad, Bashir; Kubota, Shigeru; Hirahara, Kazuhiro; Hirose, Fumihiko, E-mail: fhirose@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2015-01-01

    Room-temperature atomic layer deposition (ALD) of HfO{sub 2} was examined using tetrakis (ethylmethylamino)hafnium (TEMAH) and remote plasma-excited water and oxygen. A growth rate of 0.26?nm/cycle at room temperature was achieved, and the TEMAH adsorption and its oxidization on HfO{sub 2} were investigated by multiple internal reflection infrared absorption spectroscopy. It was observed that saturated adsorption of TEMAH occurs at exposures of ?1??10{sup 5}?L (1 L?=?1??10{sup ?6} Torr s) at room temperature, and the use of remote plasma-excited water and oxygen vapor is effective in oxidizing the TEMAH molecules on the HfO{sub 2} surface, to produce OH sites. The infrared study suggested that HfOH plays a role as an adsorption site for TEMAH. The reaction mechanism of room temperature HfO{sub 2} ALD is discussed in this paper.

  5. Mechanism of abnormally slow crystal growth of CuZr alloy

    SciTech Connect (OSTI)

    Yan, X. Q.; Lü, Y. J.

    2015-10-28

    Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed.

  6. The effects of zirconia morphology on methanol synthesis from COand H2 over Cu/ZrO2 catalysts: Part I -- Steady-State Studies

    SciTech Connect (OSTI)

    Rhodes, Michael J.; Bell, Alexis T.

    2005-03-21

    The effect of zirconia phase on the activity and selectivityof Cu/ZrO2 for the hydrogenation of CO has been investigated. Relativelypure t-ZrO2 and m-ZrO2 were prepared with high surface areas (~; 145m2/g). Copper was then deposited onto the surface of these materials byeither incipient-wetness impregnation or deposition-precipitation. For afixed Cu surface area, Cu/m-ZrO2 was tenfold more active for methanolsynthesis than Cu/t-ZrO2 from a feed of 3/1 H2/CO at 3.0 MPa andtemperatures between 473 and 523 K. Cu/m-ZrO2 also exhibited a higherselectivity to methanol. Increasing the Cu surface area on m-ZrO2resulted in further improvement in activity with minimal change inselectivity. Methanol productivity increased linearly for both Cu/t-ZrO2and Cu/m-ZrO2 with increasing Cu surface area. The difference in inherentactivity of each phase paralleled the stronger and larger CO adsorptioncapacity of the Cu/m-ZrO2 as quantified by CO-TPD. The higher COadsorption capacity of Cu/m-ZrO2 is attributed to the presence of a highconcentration of anionic vacancies on the surface of m-ZrO2. Suchvacancies expose cus-Zr4+ cations, which act as Lewis acid centers andenhance the Bronsted acidity of adjacent Zr-OH groups. The presence ofcus-Zr4+ sites and adjacent Bronsted acidic Zr-OH groups contributes tothe adsorption of CO as HCOO-Zr groups, which are the initial precursorsto methanol.

  7. Computational investigation of the phase stability and the electronic properties for Gd-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L. G.; Xiong, Y.; Xiao, W.; Cheng, L.; Du, J.; Tu, H.; Walle, A. van de

    2014-05-19

    Rare earth doping is an important approach to improve the desired properties of high-k gate dielectric oxides. We have carried out a comprehensive theoretical investigation on the phase stability, band gap, formation of oxygen vacancies, and dielectric properties for the Gd-doped HfO{sub 2}. Our calculated results indicate that the tetragonal phase is more stable than the monoclinic phase when the Gd doping concentration is greater than 15.5%, which is in a good agreement with the experimental observations. The dopant's geometric effect is mainly responsible for the phase stability. The Gd doping enlarges the band gap of the material. The dielectric constant for the Gd-doped HfO{sub 2} is in the range of 20–30 that is suitable for high-k dielectric applications. The neutral oxygen vacancy formation energy is 3.2 eV lower in the doped material than in pure HfO{sub 2}. We explain the experimental observation on the decrease of photoluminescence intensities in the Gd-doped HfO{sub 2} according to forming the dopant-oxygen vacancy complexes.

  8. Microstructure Characteristics of High Lift Factor MOCVD REBCO Coated Conductors With High Zr Content

    SciTech Connect (OSTI)

    Galstyan, E; Gharahcheshmeh, MH; Delgado, L; Xu, AX; Majkic, G; Selvamanickam, V

    2015-06-01

    We report the microstructural characteristics of high levels of Zr-added REBa2Cu3O7-x (RE = Gd, Y rare earth) coated conductors fabricated by Metal Organic Chemical Vapor Deposition (MOCVD). The enhancements of the lift factor defined as a ratio of the in-field (3 T, B parallel to c-axis) critical current density (J(c)) at 30 K and self-field J(c) at 77 K have been achieved for Zr addition levels of 20 and 25 mol% via optimization of deposition parameters. The presence of strong flux pinning is attributed to the aligned nanocolumns of BaZrO3 and nanoprecipitates embedded in REBa2Cu3O7-x matrix with good crystal quality. A high density of BZO nanorods with a typical size 6-8 nm and spacing of 20 nm has been observed. Moreover, the high Zr content was found to induce a high density of intrinsic defects, including stacking faults and dislocations. The correlation between in-field performance along the c-axis and microstructure of (Gd, Y) BCO film with a high level of Zr addition is discussed.

  9. Transfer couplings and hindrance far below the barrier for 40 Ca + 96 Zr

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stefanini, A. M.; Montagnoli, G.; Esbensen, H.; Corradi, L.; Courtin, S.; Fioretto, E.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; et al

    2015-01-29

    The sub-barrier fusion excitation function of 40Ca + 96Zr has been measured down to cross sections ≃2.4µb, i.e. two orders of magnitude smaller than obtained in the previous experiment, where the sub-barrier fusion of this system was found to be greatly enhanced with respect to 40Ca + 90Zr, and the need of coupling to transfer channels was suggested. The purpose of this work was to investigate the behavior of 40Ca + 96Zr fusion far below the barrier. The smooth trend of the excitation function has been found to continue, and the logarithmic slope increases very slowly. No indication of hindrancemore » shows up, and a comparison with 48Ca + 96Zr is very useful in this respect. A new CC analysis of the complete excitation function has been performed, including explicitly one- and two-nucleon Q >0 transfer channels. Such transfer couplings bring significant cross section enhancements, even at the level of a few µb. Locating the hindrance threshold, if any, in 40Ca + 96Zr would require challenging measurements of cross sections in the sub-µb range.« less

  10. Melting temperatures of the ZrO{sub 2}-MOX system

    SciTech Connect (OSTI)

    Uchida, T.; Hirooka, S.; Kato, M.; Morimoto, K.; Sugata, H.; Shibata, K.; Sato, D.

    2013-07-01

    Severe accidents occurred at the Fukushima Daiichi Nuclear Power Plant Units 1-3 on March 11, 2011. MOX fuels were loaded in the Unit 3. For the thermal analysis of the severe accident, melting temperature and phase state of MOX corium were investigated. The simulated coriums were prepared from 4%Pu-containing MOX, 8%Pu-containing MOX and ZrO{sub 2}. Then X-ray diffraction, density and melting temperature measurements were carried out as a function of zirconium and plutonium contents. The cubic phase was observed in the 25%Zr-containing corium and the tetragonal phase was observed in the 50% and 75%Zr-containing coria. The lattice parameter and density monotonically changed with Pu content. Melting temperature increased with increasing Pu content; melting temperature were estimated to be 2932 K for 4%Pu MOX corium and 3012 K for 8%Pu MOX corium in the 25%ZrO{sub 2}-MOX system. The lowest melting temperature was observed for 50%Zr-containing corium. (authors)

  11. Optimization and testing results of Zr-bearing ferritic steels

    SciTech Connect (OSTI)

    Tan, Lizhen; Yang, Ying; Tyburska-Puschel, Beata; Sridharan, K.

    2014-09-01

    The mission of the Nuclear Energy Enabling Technologies (NEET) program is to develop crosscutting technologies for nuclear energy applications. Advanced structural materials with superior performance at elevated temperatures are always desired for nuclear reactors, which can improve reactor economics, safety margins, and design flexibility. They benefit not only new reactors, including advanced light water reactors (LWRs) and fast reactors such as sodium-cooled fast reactor (SFR) that is primarily designed for management of high-level wastes, but also life extension of the existing fleet when component exchange is needed. Developing and utilizing the modern materials science tools (experimental, theoretical, and computational tools) is an important path to more efficient alloy development and process optimization. Ferritic-martensitic (FM) steels are important structural materials for nuclear reactors due to their advantages over other applicable materials like austenitic stainless steels, notably their resistance to void swelling, low thermal expansion coefficients, and higher thermal conductivity. However, traditional FM steels exhibit a noticeable yield strength reduction at elevated temperatures above ~500°C, which limits their applications in advanced nuclear reactors which target operating temperatures at 650°C or higher. Although oxide-dispersion-strengthened (ODS) ferritic steels have shown excellent high-temperature performance, their extremely high cost, limited size and fabricability of products, as well as the great difficulty with welding and joining, have limited or precluded their commercial applications. Zirconium has shown many benefits to Fe-base alloys such as grain refinement, improved phase stability, and reduced radiation-induced segregation. The ultimate goal of this project is, with the aid of computational modeling tools, to accelerate the development of a new generation of Zr-bearing ferritic alloys to be fabricated using conventional

  12. Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Mei, A. B.; Zhang, C.; Sardela, M.; Eckstein, J. N.; Rockett, A.; Howe, B. M.; Hultman, L.; Petrov, I.; Greene, J. E.

    2013-11-15

    Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001){sub ZrN}‖(001){sub MgO} and [100]{sub ZrN}‖[100]{sub MgO}. The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity ρ{sub 300K} of 12.0 μΩ-cm, a temperature coefficient of resistivity between 100 and 300 K of 5.6 × 10{sup −8}Ω-cm K{sup −1}, a residual resistivity ρ{sub o} below 30 K of 0.78 μΩ-cm (corresponding to a residual resistivity ratio ρ{sub 300Κ}/ρ{sub 15K} = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, ξ{sub ‖} = 18 nm and ξ{sub ⊥} = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 ± 1.7 and 450 ± 25 GPa.

  13. Obtaining composite Zr-Al-O coating on the surface of zirconium by microplasma oxidation

    SciTech Connect (OSTI)

    Gubaidulina, Tatiana A. E-mail: ostk@mail2000ru; Kuzmin, Oleg S. E-mail: ostk@mail2000ru; Fedorischva, Marina V. E-mail: kmp1980@mail.ru; Kalashnikov, Mark P. E-mail: kmp1980@mail.ru; Sergeev, Viktor P.

    2014-11-14

    The paper describes the application of the microplasma oxidation for production of Zr-Al-O composition on the surface of zirconium. Certification of a new-type power supply for depositing oxide ceramic coatings by microplasma oxidation was also carried out. The growth rate of Zr-Al-O coating amounted around 0.2 nm/s, which around 10 times exceeds that for depositing similar coatings using the similar equipment. We have studied the change of surface morphology and the chemical composition of the formed ceramic coating by means of EVO 50 scanning electron microscope and X-ray spectral analysis.

  14. Am phases in the matrix of a U–Pu–Zr alloy with Np, Am, and rare-earth elements

    SciTech Connect (OSTI)

    Janney, Dawn E.; Kennedy, J. Rory; Madden, James W.; O’Holleran, Thomas P.

    2015-01-01

    Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ζ-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and δ-(U, Np, Pu, Am)Zr2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ζ-(U, Np, Pu, Am) is higher than that in ζ-(U, Pu) and the Zr content in δ-(U, Np, Pu, Am)Zr2 is lower than that in δ-UZr2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ζ-(U, Np, Pu, Am) bracketed by zones of δ-(U, Np, Pu, Am)Zr2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ζ-(U, Np, Pu, Am) and δ-(U, Np, Pu, Am)Zr2. Each of these domains is a few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.

  15. Effect of cooling rate on the microstructure and microhardness of the CuZrAgAl alloy

    SciTech Connect (OSTI)

    Liu, Y.; Blandin, J.J.; Suery, M.; Kapelski, G.

    2012-08-15

    The effect of cooling rate on the microstructure and microhardness of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} (at.%) alloy has been studied. The crystalline phases were characterized by X-ray diffraction, optical microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy, and identified as AlCu{sub 2}Zr, Cu{sub 10}Zr{sub 7} and CuZr{sub 2}. The solidification sequence was established as following: the Cu{sub 10}Zr{sub 7} phase forms first in the periphery of the rod, then following with AlCu{sub 2}Zr phase in the rod center and finally CuZr{sub 2} crystals in Cu-depleted areas. The effect of crystals on the mechanical properties of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was also estimated through the microhardness. According to the value of microhardness, inhomogeneous structure of the amorphous matrix is more easily formed for the alloy in the low cooling rate (i.e., 9 mm) as compared with the alloy with fully amorphous state in the large cooling rate (i.e., 3 mm). This inhomogeneous structure was attributed to the composition change of amorphous matrix arising from the forming of crystalline phases due to the low cooling rate. - Highlights: Black-Right-Pointing-Pointer The crystalline phases in the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy were identified. Black-Right-Pointing-Pointer The solidification sequence of Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was verified. Black-Right-Pointing-Pointer The softening and hardening of alloy could be observed due to the crystallization.

  16. Enhancement of perpendicular magnetic anisotropy and transmission of spin-Hall-effect-induced spin currents by a Hf spacer layer in W/Hf/CoFeB/MgO layer structures

    SciTech Connect (OSTI)

    Pai, Chi-Feng; Nguyen, Minh-Hai; Vilela-Leão, Luis Henrique; Buhrman, R. A.; Belvin, Carina; Ralph, D. C.

    2014-02-24

    We report that strong perpendicular magnetic anisotropy of the ferromagnetic layer in a W/CoFeB/MgO multilayer structure can be established by inserting a Hf layer as thin as 0.25 nm between the W and CoFeB layers. The Hf spacer also allows transmission of spin currents generated by an in-plane charge current in the W layer to apply strong spin torque on the CoFeB, thereby enabling current-driven magnetic switching. The antidamping-like and field-like components of the spin torque exerted on a 1 nm CoFeB layer are of comparable magnitudes in this geometry. Both components originate from the spin Hall effect in the underlying W layer.

  17. Effect of the oxide layer on current-induced spin-orbit torques in Hf|CoFeB|MgO and Hf|CoFeB|TaO{sub x} structures

    SciTech Connect (OSTI)

    Akyol, Mustafa; Alzate, Juan G.; Yu, Guoqiang; Upadhyaya, Pramey; Wong, Kin L.; Khalili Amiri, Pedram; Wang, Kang L.; Ekicibil, Ahmet

    2015-01-19

    We study the effect of the oxide layer on the current-induced spin-orbit torques (SOTs) in perpendicularly magnetized Hf|CoFeB|MgO (MgO-capped) or Hf|CoFeB|TaO{sub x} (TaO{sub x}-capped) structures. The effective fields corresponding to both the field-like and damping-like current-induced SOTs are characterized using electric transport measurements. Both torques are found to be significantly stronger in MgO-capped structures than those in TaO{sub x}-capped structures. The difference in field-like and damping-like SOTs in the different structures may be attributed to the different Rashba-like Hamiltonian, arising from the difference in the electric potential profiles across the oxide|ferromagnet interfaces in the two cases, as well as possible structural and oxidation differences in the underlying CoFeB and Hf layers. Our results show that the oxide layer in heavy-metal|ferromagnet|oxide trilayer structures has a very significant effect on the generated SOTs for manipulation of ferromagnetic layers. These findings could potentially be used to engineer SOT devices with enhanced current-induced switching efficiency.

  18. Morphology and chemical termination of HF-etched Si{sub 3}N{sub 4} surfaces

    SciTech Connect (OSTI)

    Liu, Li-Hong; Debenedetti, William J. I.; Peixoto, Tatiana; Gokalp, Sumeyra; Shafiq, Natis; Veyan, Jean-François; Chabal, Yves J.; Michalak, David J.; Hourani, Rami

    2014-12-29

    Several reports on the chemical termination of silicon nitride films after HF etching, an important process in the microelectronics industry, are inconsistent claiming N-H{sub x}, Si-H, or fluorine termination. An investigation combining infrared and x-ray photoelectron spectroscopies with atomic force and scanning electron microscopy imaging reveals that under some processing conditions, salt microcrystals are formed and stabilized on the surface, resulting from products of Si{sub 3}N{sub 4} etching. Rinsing in deionized water immediately after HF etching for at least 30 s avoids such deposition and yields a smooth surface without evidence of Si-H termination. Instead, fluorine and oxygen are found to terminate a sizeable fraction of the surface in the form of Si-F and possibly Si-OH bonds. The relatively unique fluorine termination is remarkably stable in both air and water and could lead to further chemical functionalization pathways.

  19. The role of the Ganges-Brahmaputra mixing zone in supplying barium and [sup 226]Ra to the Bay of Bengal

    SciTech Connect (OSTI)

    Carroll, J. Univ. of Alaska, Fairbanks ); Falkner, K.K. CNES, Toulouse ); Brown, E.T. ); Moore, W.S. )

    1993-07-01

    The Ganges-Brahmaputra river system is ranked fourth among world rivers as a source of freshwater to the oceans and is believed to supply more sediment to the ocean than any other; 1.5 [times] 10[sup 12] kg/yr (Milliman and Meade, 1983). Barium and [sup 226]Ra are typically enriched in waters where sediment-laden rivers enter the ocean. As such, the Ganges-Brahmaputra is likely to produce globally significant barium and [sup 226]Ra fluxes to the ocean. Water samples for barium and [sup 226]Ra were collected within four major channels of the Ganges-Brahmaputra mixing zone during a period of low sediment and freshwater discharge. The data suggest that in addition to suspended sediments supplied directly from rivers, river sediments deposited during high discharge in mangroves and on islands are desorbing barium and [sup 226]Ra to seawater. The release of barium and [sup 226]Ra from these sediment deposits is out-of-phase with the direct supply of sediments from the rivers. Estimates of the annual fluxes of barium and [sup 226]Ra from the Ganges-Brahmaputra mixing zone were also derived. The fluxes of barium and [sup 226]Ra are 5.3 [times] 10[sup 8] mol barium/yr and 9.5 [times] 10[sub 14] dpm radium/yr. The first silicate and phosphate mixing profiles for this system are reported. 29 refs., 6 figs., 3 tabs.

  20. Experiments and theory on parametric instabilities excited in HF heating experiments at HAARP

    SciTech Connect (OSTI)

    Kuo, Spencer; Snyder, Arnold; Lee, M. C.

    2014-06-15

    Parametric instabilities excited by O-mode HF heater and the induced ionospheric modification were explored via HAARP digisonde operated in a fast mode. The impact of excited Langmuir waves and upper hybrid waves on the ionosphere are manifested by bumps in the virtual spread, which expand the ionogram echoes upward as much as 140 km and the downward range spread of the sounding echoes, which exceeds 50 km over a significant frequency range. The theory of parametric instabilities is presented. The theory identifies the ionogram bump located between the 3.2 MHz heater frequency and the upper hybrid resonance frequency and the bump below the upper hybrid resonance frequency to be associated with the Langmuir and upper hybrid instabilities, respectively. The Langmuir bump is located close to the upper hybrid resonance frequency, rather than to the heater frequency, consistent with the theory. Each bump in the virtual height spread of the ionogram is similar to the cusp occurring in daytime ionograms at the E-F2 layer transition, indicating that there is a small ledge in the density profile similar to E-F2 layer transitions. The experimental results also show that the strong impact of the upper hybrid instability on the ionosphere can suppress the Langmuir instability.

  1. The Concentrations of {sup 40}K, {sup 226}Ra and {sup 232}Th in Soil Sample in Osmaniye (Turkey)

    SciTech Connect (OSTI)

    Akkurt, I.; Guenoglu, K.; Kara, A.; Mavi, B.; Karaboerklue, S.

    2011-12-26

    The {sup 40}K, {sup 226}Ra and {sup 232}Th concentration is due to the magmatic structure of the earth and it can be varied from place to place. Osmaniye is located in the Eastern side of Mediteranean Region. It holds the climatic characteristics of the same region and arises with Middle Taurus Mountains from west to North and with Amonos Mounations in East and West-east parts and is situated between 35 deg. .52'-36 deg. .42' east longitudes and 36 deg. .57'-37 deg. .45' north latitudes. In this study, the natural radioactivity concentrations {sup 40}K, {sup 226}Ra and {sup 232}Th in some soil samples collected in Osmaniye have been investigated. The measurements have been performed using 3x3{sup ''} NaI(Tl) detector system.

  2. The Isoscalar Giant Dipole Resonance in {sup 20}Pb, {sup 90}Zr and the Nuclear Compressibility

    SciTech Connect (OSTI)

    Yildirim, Serbulent; Koeroglu, Ulas

    2008-11-11

    The isoscalar giant dipol resonance (ISGDR) in finite nuclei is studied within the framework of a relativistic transport approach. The excitation energies of spherical {sup 90}Zr and {sup 208}Pb nuclei are obtained for different quantum hydrodynamical Lagrangian parametrization. The sensitivity of ISGDR excitation energy on the nuclear bulk to surface properties are also investigated.

  3. Zr doped anatase supported reticulated ceramic foams for photocatalytic water purification

    SciTech Connect (OSTI)

    Plesch, G.; Vargov, M.; Vogt, U.F.; Department of Crystallography, University of Freiburg, D-79104 Freiburg ; Gorbr, M.; Jesenk, K.

    2012-07-15

    Highlights: ? Thick photocatalytic anatase films on macroporous reticulated ceramic foams. ? Alumina and aluminamullite macroporous reticulated foams as photocatalyst support. ? Zr doping significantly improves the TiO{sub 2} film activity in phenol photomineralization. ? Comparison of photocatalytic activity of thick films and powder suspensions. -- Abstract: Titanium dioxide films were deposited on macroporous reticulated Al{sub 2}O{sub 3} and aluminamullite foams with pore sizes of 15 ppi (pores per inch). Coatings were prepared from suspensions of precursor powders of Aeroxide{sup } P25 nanopowder and precipitated TiO{sub 2} by using a dip coating process. The TiO{sub 2} forms films with a thickness of ?220 ?m. The photocatalytic activity was characterized as the mineralization rate of an aqueous phenol solution under UVA irradiation by the TOC technique. Precipitated TiO{sub 2} films have nearly the same photocatalytic activity as a titania suspension, in which powder aggregates have a size comparable with the thickness of the films. Samples made of Aeroxide{sup } P25 nanopowder, in which the size of aggregates is ?0.1 ?m show higher efficiency of photodecomposition in suspensions with films. The doping of precipitated anatase with Zr(IV) in the atomic ratio Zr/Ti = 0.008 significantly improves the photocatalytic activity of the foam supported titania. Zr doped anatase films show better performance as the films prepared only from Aeroxide{sup } P25 nanopowder.

  4. Features of the band structure and conduction mechanisms in the n-HfNiSn semiconductor heavily doped with Ru

    SciTech Connect (OSTI)

    Romaka, V. A.; Rogl, P.; Romaka, V. V.; Stadnyk, Yu. V.; Korzh, R. O.; Krayovskyy, V. Ya.; Horyn, A. M.

    2014-12-15

    The crystal and electronic structure and energy and kinetic properties of the n-HfNiSn semiconductor heavily doped with a Ru acceptor impurity are investigated in the temperature and Ru concentration ranges T = 80400 K and N{sub A}{sup Ru} ? 9.5 10{sup 19}?5.7 10{sup 20} cm{sup ?3} (x = 00.03), respectively. The mechanism of structural-defect generation is established, which changes the band gap and degree of compensation of the semiconductor and consists in the simultaneous concentration reduction and elimination of donor structural defects by means of the displacement of ?1% of Ni atoms from the Hf (4a) positions, the generation of acceptor structural defects upon the substitution of Ru atoms for Ni atoms in the 4c positions, and the generation of donor defects in the form of vacancies in the Sn (4b) positions. The calculated electronic structure of HfNi{sub 1?x}Ru{sub x}Sn is consistent with the experiment. The results obtained are discussed within the Shklovsky-Efros model for a heavily doped and compensated semiconductor.

  5. The Department of Energy's American Recovery and Reinvestment Act - California State Energy Program, OAS-RA-11-10

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    American Recovery and Reinvestment Act - California State Energy Program OAS-RA-11-10 July 2011 Department of Energy Washington, DC 20585 July 28, 2011 MEMORANDUM FOR THE ACTING ASSISTANT SECRETARY FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: George W. Collard Assistant Inspector General for Audits Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Department of Energy's American Recovery and Reinvestment Act - California State Energy Program" BACKGROUND The

  6. Waste Disposal and Recovery Act Efforts at the Oak Ridge Reservation,OAS-RA-L-12-01

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Inspection Report Waste Disposal and Recovery Act Efforts at the Oak Ridge Reservation INS-RA-L-12-01 December 2011 Department of Energy Washington, DC 20585 December 16, 2011 MEMORANDUM FOR THE MANAGER, OAK RIDGE OFFICE FROM: Sandra D. Bruce Assistant Inspector General for Inspections Office of Inspector General SUBJECT: INFORMATION: Inspection Report on "Waste Disposal and Recovery Act Efforts at the Oak Ridge Reservation" BACKGROUND The Department of Energy's (Department) expends

  7. Structural and spectroscopic properties of high temperature prepared ZrO₂–TiO₂ mixed oxides

    SciTech Connect (OSTI)

    Gionco, Chiara; Battiato, Alfio; Vittone, Ettore; Paganini, Maria Cristina; Giamello, Elio

    2013-05-01

    ZrO₂-TiO₂ mixed oxides of various composition, with the molar fraction of TiO₂ ranging from 0.1% to 15%, have been prepared via sol-gel synthesis and then calcined at 1273 K to check both their thermal stability and physicochemical properties. These solids are usually employed in photocatalytic processes and as active phase supports in heterogeneous catalysis. As indicated by X-ray diffraction and Raman spectroscopy, solid solutions based on Ti ions diluted in the ZrO₂ matrix are formed in the whole range of Ti molar fraction examined. Materials with low Ti loading (0.1%–1%) are basically constituted by the monoclinic phase of ZrO₂ while the tetragonal phase becomes prevalent at 15% of TiO₂ molar fraction. The presence of Ti ions modify the electronic structure of the solid as revealed by investigation of the optical properties. The typical band gap transition of ZrO₂ undergoes, in fact, a red shift roughly proportional to the Ti loading which reach the remarkable value of 1.6 eV for the sample with 10% of molar Ti concentration. Comparing chemical analysis of the solids with XPS data it has been put into evidence that the titanium ions distribution into the solid is not uniform and the concentration of Ti⁴⁺ tend to be higher in subsurface layers than in the crystal bulk. The introduction of titanium ions in the structure increases the reducibility of the solid. Annealing under vacuum at various temperatures causes oxygen depletion with consequent reduction of the solid which shows up mainly in terms of formation of Ti³⁺ reduced centres which are characterized by a typical EPR signal. Ti³⁺ defects forms, as also forecast by theoretical modelling of the solid, as their energy is lower than that of other possible reduced defective centers. The reduced solids are able to transfer electrons to adsorbed oxygen molecules in mild condition resulting in the formation of surface superoxide anions (O₂⁻) which are stabilized on surface Zr

  8. Role of HfO2/SiO2 thin-film interfaces in near-ultraviolet absorption and pulsed laser damage

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Papernov, Semyon; Kozlov, Alexei A.; Oliver, James B.; Smith, Chris; Jensen, Lars; Guenster, Stefan; Maedebach, Heinrich; Ristau, Detlev

    2016-07-15

    Here, the role of thin-film interfaces in the near-ultraviolet (near-UV) absorption and pulsed laser-induced damage was studied for ion-beam-sputtered and electron-beam-evaporated coatings comprised from HfO2 and SiO2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO2 single-layer film and for a film containing seven narrow HfO2 layers separated by SiO2 layers. The seven-layer film was designed to have a total optical thickness of HfO2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similarmore » to a single-layer HfO2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces as compared to HfO2 film material. The relevance of obtained absorption data to coating near-UV, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO2 film in both sputtered and evaporated coatings. The results are explained through the similarity of interfacial film structure with structure formed during the codeposition of HfO2 and SiO2 materials.« less

  9. Structural and microstructural changes in monoclinic ZrO{sub 2} during the ball-milling with stainless steel assembly

    SciTech Connect (OSTI)

    Stefanic, G. . E-mail: stefanic@irb.hr; Music, S.; Gajovic, A.

    2006-04-13

    High-energy ball-milling of monoclinic ZrO{sub 2} was performed in air using the planetary ball mill with a stainless steel milling assembly. Structural and microstructural changes during the ball-milling were monitored using X-ray powder diffraction, Raman spectroscopy, Moessbauer spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectrometry. The results of line broadening analysis indicated a decrease in the crystallite size and an increase in the microstrains with the ball-milling time increased up to {approx}150 min. The results of quantitative phase analysis indicated the presence of a very small amount of tetragonal ZrO{sub 2} phase in this early stage of ball-milling. The onset of m-ZrO{sub 2} {sup {yields}} t-ZrO{sub 2} transition occurred between 10 and 15 h of ball-milling, which resulted in a complete transition after 20 h of ball-milling. Further ball-milling caused a decrease of the t-ZrO{sub 2} lattice parameters followed by a probable transition into c-ZrO{sub 2}. It was concluded that the stabilization of t- and c-ZrO{sub 2} polymorphs at RT can be attributed to the incorporation of aliovalent cations (Fe{sup 2+}, Fe{sup 3+} and Cr{sup 3+}) introduced into the sample due to the wear and oxidation of the milling media.

  10. Addition of the Neurokinin-1-Receptor Antagonist (RA) Aprepitant to a 5-Hydroxytryptamine-RA and Dexamethasone in the Prophylaxis of Nausea and Vomiting Due to Radiation Therapy With Concomitant Cisplatin

    SciTech Connect (OSTI)

    Jahn, Franziska; Jahn, Patrick; Sieker, Frank; Vordermark, Dirk; Jordan, Karin

    2015-08-01

    Purpose: To assess, in a prospective, observational study, the safety and efficacy of the addition of the neurokinin-1-receptor antagonist (NK1-RA) aprepitant to concomitant radiochemotherapy, for the prophylaxis of radiation therapy–induced nausea and vomiting. Patients and Methods: This prospective observational study compared the antiemetic efficacy of an NK1-RA (aprepitant), a 5-hydroxytryptamine-RA, and dexamethasone (aprepitant regimen) versus a 5-hydroxytryptamine-RA and dexamethasone (control regimen) in patients receiving concomitant radiochemotherapy with cisplatin at the Department of Radiation Oncology, University Hospital Halle (Saale), Germany. The primary endpoint was complete response in the overall phase, defined as no vomiting and no use of rescue therapy in this period. Results: Fifty-nine patients treated with concomitant radiochemotherapy with cisplatin were included in this study. Thirty-one patients received the aprepitant regimen and 29 the control regimen. The overall complete response rates for cycles 1 and 2 were 75.9% and 64.5% for the aprepitant group and 60.7% and 54.2% for the control group, respectively. Although a 15.2% absolute difference was reached in cycle 1, a statistical significance was not detected (P=.22). Furthermore maximum nausea was 1.58 ± 1.91 in the control group and 0.73 ± 1.79 in the aprepitant group (P=.084); for the head-and-neck subset, 2.23 ± 2.13 in the control group and 0.64 ± 1.77 in the aprepitant group, respectively (P=.03). Conclusion: This is the first study of an NK1-RA–containing antiemetic prophylaxis regimen in patients receiving concomitant radiochemotherapy. Although the primary endpoint was not obtained, the absolute difference of 10% in efficacy was reached, which is defined as clinically meaningful for patients by international guidelines groups. Randomized phase 3 studies are necessary to further define the potential role of an NK1-RA in this setting.

  11. Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

    SciTech Connect (OSTI)

    Adibi, Sara [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore); Branicio, Paulo S., E-mail: branicio@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Joshi, Shailendra P., E-mail: Shailendra@nus.edu.sg [Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)

    2014-07-28

    Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15?nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5?nm for Cu{sub 36}Zr{sub 64} and 3?nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54?GPa/1.29?GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57?GPa /1.58?GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

  12. Glass formation in binary and ternary Zr based Fe and Ni bearing alloys

    SciTech Connect (OSTI)

    Savalia, R.T.; Tewari, R.; Banerjee, S.; Dey, G.K.

    1996-01-01

    Rapid solidification of the Zr{sub 76}Fe{sub 24-x}Ni{sub x} alloys (x - 0, 4, 8, 12, 16, 20 and 24) by melt spinning under different conditions has yielded fully amorphous as well as partially crystalline ribbons. The partially crystalline ribbons have been found to contain crystal aggregates comprising a core of the {beta}-Zr phase surrounded by peripheral crystals of the Zr{sub 3}(Fe,Ni) phase in alloys with x < 12. In alloys containing larger amount of Ni (x {ge} 12), both Zr{sub 2}Ni and Zr{sub 3}(Fe,Ni) crystals have been found to be present in the periphery. The nucleation of the core crystals and the peripheral crystals in the undercooled melt has been examined by considering transient and steady state homogeneous and heterogeneous nucleation. The transient nucleation time and the steady state nucleation rate of crystals have been evaluated. For this purpose, use has been made of molar free energy difference {Delta}G{sub c} between the liquid and the crystalline phases determined from experimentally evaluated quantities. The growth of the crystals in the undercooled melt has been examined taking into account recalescence and heat removal during melt spinning. The glass forming ability of the alloys has been evaluated on the basis of the avoidance of crystallization approach. A comparison has been made between the microstructures of the splat cooled and the melt spun alloys in order to understand the process of solidification and the nature of phase transformation during post solidification cooling.

  13. Effect of Zr on microstructures and mechanical properties of an Al-Mg-Si-Cu-Cr alloy prepared by low frequency electromagnetic casting

    SciTech Connect (OSTI)

    Meng, Yi, E-mail: yimonmy@sina.com; Cui, Jianzhong; Zhao, Zhihao; He, Lizi

    2014-06-01

    The Al-1.6Mg-1.2Si-1.1Cu-0.15Cr (all in wt. %) alloys with and without Zr addition prepared by low frequency electromagnetic casting process were investigated by using the optical microscope, scanning electron microscope and transmission electron microscope equipped with energy dispersive analytical X-ray. The effects of Al{sub 3}Zr phases on the microstructures and mechanical properties during solidification, homogenization, hot extrusion and solid solution were studied. The results show that Al{sub 3}Zr phases reduce the grain size by ? 29% and promote the formation of an equiaxed grain structure during solidification. Numerous spherical Al{sub 3}Zr dispersoids with 3560 nm in diameters precipitate during homogenization, and these fine dispersoids change little during subsequent hot extrusion and solid solution. Adding 0.15 wt. % Zr results in no recrystallization after hot extrusion and partial recrystallization after solid solution, while the recrystallized grain size is 400550 ?m in extrusion direction in the Zr-free alloy. In addition, adding 0.15 wt. % Zr can obviously promote Q? phase precipitation, while the ?? phases are predominant in the alloy without Zr. Adding 0.15 wt. % Zr, the ultimate tensile strength of the T6 treated alloy increases by 45 MPa, while the elongation remains about 16.7%. - Highlights: Minor Zr can refine as-cast grains of the LFEC Al-Mg-Si-Cu-Cr alloy. L1{sub 2} Al{sub 3}Zr phases with 3560 nm in diameter precipitate during homogenization. L1{sub 2} and DO{sub 22} Al{sub 3}Zr phases result in partial recrystallization after solid solution. Minor Zr can promote the precipitation of Q? phases. Mechanical properties of Al-Mg-Si-Cu-Cr-Zr alloy are higher than those of AA7005.

  14. The integration of Human Factors (HF) in the SAR process training course text

    SciTech Connect (OSTI)

    Ryan, T.G.

    1995-03-01

    This text provides the technical basis for a two-day course on human factors (HF), as applied to the Safety Analysis Report (SAR) process. The overall objective of this text and course is to: provide the participant with a working knowledge of human factors-related requirements, suggestions for doing a human safety analysis applying a graded approach, and an ability to demonstrate using the results of the human safety analysis, that human factors elements as defined by DOE (human factors engineering, procedures, training, oversight, staffing, qualifications), can support wherever necessary, nuclear safety commitments in the SAR. More specifically, the objectives of the text and course are: (1) To provide the SAR preparer with general guidelines for doing HE within the context of a graded approach for the SAR; (2) To sensitize DOE facility managers and staff, safety analysts and SAR preparers, independent reviewers, and DOE reviewers and regulators, to DOE Order 5480.23 requirements for HE in the SAR; (3) To provide managers, analysts, reviewers and regulators with a working knowledge of HE concepts and techniques within the context of a graded approach for the SAR, and (4) To provide SAR managers and DOE reviewers and regulators with general guidelines for monitoring and coordinating the work of preparers of HE inputs throughout the SAR process, and for making decisions regarding the safety relevance of HE inputs to the SAR. As a ready reference for implementing the human factors requirements of DOE Order 5480.22 and DOE Standard 3009-94, this course text and accompanying two-day course are intended for all persons who are involved in the SAR.

  15. Synthesis and physicochemical properties of Zr-MCM-41 mesoporous molecular sieves and Pt/H{sub 3}PW{sub 12}O{sub 40}/Zr-MCM-41 catalysts

    SciTech Connect (OSTI)

    Chen, L.F. Wang, J.A.; Norena, L.E.; Aguilar, J.; Navarrete, J.; Salas, P.; Montoya, J.A.; Del Angel, P.

    2007-10-15

    For the first time, modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr{sup 4+} ions into the framework are investigated. The Zr-modified Si-MCM-41 mesoporous materials (hereafter referred as WSZn, n=Si/Zr=25, 15, 8, 4) were synthesized through a surfactant-templated preparation approach, using low-cost fumed silica as the Si precursor. After impregnation with 25 wt% of H{sub 3}PW{sub 12}O{sub 40}, the surface Broensted acidity of the Pt/H{sub 3}PW{sub 12}O{sub 40}/WSZn catalysts was greatly enhanced by 2-10 times relative to the bare WSZn support. Two kinds of supported heteropolyacids were formed: (i) bulk-like heteropolyacid crystals with unchanged Keggin structures, and (ii) highly dispersed heteropolyacid with distorted Keggin units. The formation of various kinds of heteropolyacid structures is closely related to the interaction between the heteropolyanions and the hydroxyl groups in the host support. - Graphical abstract: Modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr{sup 4+} ions into the framework are investigated. Broensted acidity of the Pt/H{sub 3}PW{sub 12}O{sub 40}/Zr-MCM-41 catalysts was greatly enhanced by 2-10 times relative to the bare Zr-MCM-41 support.

  16. Reactive sputtering of ?-ZrH{sub 2} thin films by high power impulse magnetron sputtering and direct current magnetron sputtering

    SciTech Connect (OSTI)

    Hgberg, Hans Tengdelius, Lina; Eriksson, Fredrik; Broitman, Esteban; Lu, Jun; Jensen, Jens; Hultman, Lars; Samuelsson, Mattias

    2014-07-01

    Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H{sub 2} plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at.?% and O contents typically below 0.2 at.?% as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of ?0.7?eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase ?-ZrH{sub 2} (CaF{sub 2} type structure) at H content >?55 at.?% and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.57 GPa for the ?-ZrH{sub 2} films that is slightly harder than the ?5 GPa determined for Zr films and with coefficients of friction in the range of 0.120.18 to compare with the range of 0.40.6 obtained for Zr films. Wear resistance testing show that phase-pure ?-ZrH{sub 2} films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of ?100120 ?? cm for the ?-ZrH{sub 2} films, which is slightly higher compared to Zr films with values in the range 7080 ?? cm.

  17. Thermal behavior of the amorphous precursors of the ZrO{sub 2}-SnO{sub 2} system

    SciTech Connect (OSTI)

    Stefanic, Goran Music, Svetozar; Ivanda, Mile

    2008-11-03

    Thermal behavior of the amorphous precursors of the ZrO{sub 2}-SnO{sub 2} system on the ZrO{sub 2}-rich side of the concentration range, prepared by co-precipitation from aqueous solutions of the corresponding salts, was monitored using differential thermal analysis, X-ray powder diffraction, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). The crystallization temperature of the amorphous precursors increased with an increase in the SnO{sub 2} content, from 405 deg. C (0 mol% SnO{sub 2}) to 500 deg. C (40 mol% SnO{sub 2}). Maximum solubility of Sn{sup 4+} ions in the ZrO{sub 2} lattice ({approx}25 mol%) occurred in the metastable products obtained upon crystallization of the amorphous precursors. A precise determination of unit-cell parameters, using both Rietveld and Le Bail refinements of the powder diffraction patterns, shows that the incorporation of Sn{sup 4+} ions causes an asymmetric distortion of the monoclinic ZrO{sub 2} lattice. The results of phase analysis indicate that the incorporation of Sn{sup 4+} ions has no influence on the stabilization of cubic ZrO{sub 2} and negligible influence on the stabilization of tetragonal ZrO{sub 2}. Partial stabilization of tetragonal ZrO{sub 2} in products having a tin content above its solid-solubility limit was attributed to the influence of ZrO{sub 2}-SnO{sub 2} surface interactions. In addition to phases closely structurally related to cassiterite, monoclinic ZrO{sub 2} and tetragonal ZrO{sub 2}, a small amount of metastable ZrSnO{sub 4} phase appeared in the crystallization products of samples with 40 and 50 mol% of SnO{sub 2} calcined at 1000 deg. C. Further temperature treatments caused a decrease in and disappearance of metastable phases. The results of the micro-structural analysis show that the sinterability of the crystallization products significantly decreases with an increase in the SnO{sub 2} content.

  18. The photoluminescence properties of Er{sup 3+}-doped ZrO{sub 2} nanotube arrays prepared by anodization

    SciTech Connect (OSTI)

    Wang, Xixin; Zhao, Jianling; Du, Peng; Guo, Limin; Xu, Xuewen; Tang, Chengchun

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ? Er{sup 3+}-doped ZrO{sub 2} nanotube arrays were prepared by anodization of ZrEr alloy. ? Small tetragonal zirconia crystallites are tended to be formed due to the doping of Er{sup 3+}. ? Under excitation at 317 nm, the ZrO{sub 2} nantube arrays have strongest photoluminescence intensity. -- Abstract: Er{sup 3+}-doped ZrO{sub 2} nanotube arrays were prepared by anodization of ZrEr alloy which was obtained by melting zirconium with 1.0 wt% erbium. The morphology, structure and photoluminescence properties were studied through scanning electron microscope, transmission electron microscope, X-ray diffraction and photoluminescence analyzer. X-ray diffraction results indicate that doping of Er{sup 3+} affects the crystal structure and grain size obviously and the Er{sup 3+}-doped samples tend to form small tetragonal grains. Photoluminescence analyses show that when Er{sup 3+}-doped zirconia nanotube arrays are excited at 317 nm, there are two strong photoluminescence emission peaks at 373 nm and 415 nm. When the excitation wavelength is 257 nm, a photoluminescence emission peak appears at 363 nm. Under same measurement conditions, emission peaks of the undoped ZrO{sub 2} nanotube arrays are very weak.

  19. Atomic disorder in Gd{sub 2}Zr{sub 2}O{sub 7} pyrochlore

    SciTech Connect (OSTI)

    Zhang, F. X.; Lang, M.; Ewing, R. C.

    2015-05-11

    Gd{sub 2}Zr{sub 2}O{sub 7} pyrochlore with different degrees of cation disorder were synthesized by isothermal annealing at various temperatures (1100–1550 °C), and the related changes in the structure were investigated by ambient and high pressure x-ray diffraction (XRD) measurements. Unit cell parameters increase almost linearly with increasing treatment temperature. The degree of cation order in pyrochlore also increases with the increase of temperature, but saturates at ∼60%. The compressibility of the pyrochlore structures decreases when the degree of cation order increases. High pressure XRD measurements also indicate that the phase stability of Gd{sub 2}Zr{sub 2}O{sub 7} is not very sensitive to the degree of atomic disorder in the pyrochlore structure.

  20. Unique properties of CuZrAl bulk metallic glasses induced by microalloying

    SciTech Connect (OSTI)

    Huang, B.; Bai, H. Y.; Wang, W. H.

    2011-12-15

    We studied the glass forming abilities (GFA), mechanical, and physical properties of (CuZr){sub 92.5}Al{sub 7}X{sub 0.5} (X = La, Sm, Ce, Gd, Ho, Y, and Co) bulk metallic glasses (BMGs). We find that the GFA, mechanical, and physical properties can be markedly changed and modulated by the minor rare earth addition. The Kondo screening effect is found to exist in (CuZr){sub 92.5}Al{sub 7}Ce{sub 0.5} BMG at low temperatures and the Schottky effect exists in all the rare earth element doped BMGs. Our results indicate that the minor addition is an effective way for modulating and getting desirable properties of the BMGs. The mechanisms of the effects of the addition are discussed. The results have implications for the exploration of metallic glasses and for improving the mechanical and low temperature physical properties of BMGs.

  1. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    SciTech Connect (OSTI)

    Kalay, Ilkay

    2010-12-15

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental

  2. Permeability of CoNbZr amorphous thin films over a wide frequency range

    SciTech Connect (OSTI)

    Koyama, H.; Tsujimoto, H.; Shirae, K.

    1987-09-01

    CoNbZr amorphous films have attracted the attention of many researchers because of their high saturation magnetization, high permeability, low coercivity, and nearly zero magnetostriction. For these films to be used, one of the important magnetic properties is the behavior of the permeability over a wide frequency range. We have measured the permeability of a square-shaped magnetic film (13 mm x 55 mm) sputtered on a glass substrate from 1 MHz to 400 MHz using a stripline. Over 400 MHz, the permeability of the magnetic film was measured using a ring-shaped sample mounted in a coaxial fixture. The wall motion permeability of CoNbZr amorphous films decreases from 1 kHz to nearly zero at 1 MHz. The rotation permeability is constant to 100 MHz and ferromagnetic resonance is observed near 1 GHz.

  3. Superacid Catalyzed Depolymerization and Conversion of Coals. Final Technical Report. [HF:BF{sub 2}/H{sub 2}

    DOE R&D Accomplishments [OSTI]

    Olah, G.

    1980-01-01

    We were interested in applying superacid catalyzed cleavage-depolymerization and ionic hydrogenation low temperature conversion of coal to liquid hydrocarbon, as well as obtaining information about the reactions involved and the structure of intermediates of the coal liquefaction process. In order to show the feasibility of our proposed research we have carried out preliminary investigation in these areas. Preceding our work there was no practical application of a superacid system to coal liquefaction. We carried out an extensive study of the potential of the HF:BF{sub 3}/H{sub 2} system for coal hydroliquefaction. Under varying conditions of reactant ratio, reaction time and temperature, we were able to obtain over 95% pyridine extractible product by treating coal in HF:BF{sub 3}:H{sub 2} system at approx. 100 degrees C for 4 hours. The coal to acid ratio was 1:5 and FB{sub 3} at 900 psi and H{sub 2} at 500 psi were used. These are extremely encouraging results in that the conditions used are drastically milder than those used in any known process, such as Exxon donor solvent and related processes. The cyclohexane extractibility of the treated coal was as high as 27% and the yield of liquid distillate at 400 degrees C/5 x 10{sup -3}/sup torr/ was approx. 30%. The infrared spectrum of product coal, extracts and distillates were distinctly different from the starting coal and show a significant increase in the amount of saturates. The {sup 1}H NMR spectrum of cyclohexane extract of the treated coal shows essentially all aliphatic photons. The spectra of other treated coal extracts show increased amounts and types of aliphatic protons as well as significant amounts of protons bound to unsaturated sites. This again indicates that the HF-BF{sub 3} system is depolymerizing the coal to small fragments which are soluble in non-polar solvents.

  4. DOE/RA/50354 Volume II FEAS)IBILITY STUDY FOR A 10 MM GPY FUEL ETHANOL PLANT

    Office of Scientific and Technical Information (OSTI)

    DOE/RA/50354 Volume II FEAS)IBILITY STUDY FOR A 10 MM GPY FUEL ETHANOL PLANT BRADY HOT SPRINGS, NEVADA . Volume II - Geothermal Resource, Agricultural Feedstock, Markets and E c o q h i c Viability 8 *e _. - - * 7 , - - - September 1980 i Prepared by Geothermal Food Processors, Inc. Fernley, Nevada and The Andersen Group DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof,

  5. High strength Sn-Mo-Nb-Zr alloy tubes and method of making same

    DOE Patents [OSTI]

    Cheadle, Brian A.

    1977-01-01

    Tubes for use in nuclear reactors fabricated from a quaternary alloy comprising 2.5-4.0 wt% Sn, 0.5-1.5 wt% Mo, 0.5-1.5 wt% Nb, balance essentially Zr. The tubes are fabricated by a process of hot extrusion, heat treatment, cold working to size and age hardening, so as to produce a microstructure comprising elongated .alpha. grains with an acicular transformed .beta. grain boundary phase.

  6. Separate effects identification via casting process modeling for experimental measurement of UPuZr alloys

    SciTech Connect (OSTI)

    J. Crapps; D. S. DeCroix; J. D. Galloway; D. A. Korzekwa; R. Aikin; R. Fielding; R. Kennedy; C. Unal

    2013-11-01

    Computational simulations of gravity casting processes for metallic UPuZr nuclear fuel rods have been performed using a design-of-experiments technique to determine the fluid flow, liquid heat transfer, and solid heat transfer parameters which most strongly influence the process solidification speed and fuel rod porosity. The results are used to make recommendations for the best investment of experimental time and effort to measure process parameters.

  7. Room temperature strain rate sensitivity in precursor derived HfO{sub 2}/Si-C-N(O) ceramic nanocomposites

    SciTech Connect (OSTI)

    Sujith, Ravindran; Kumar, Ravi

    2014-01-15

    Investigation on the room temperature strain rate sensitivity using depth sensing nanoindentation is carried out on precursor derived HfO{sub 2}/Si-C-N(O) ceramic nanocomposite sintered using pulsed electric current sintering. Using constant load method the strain rate sensitivity values are estimated. Lower strain rate sensitivity of ? 3.7 10{sup ?3} is observed and the limited strain rate sensitivity of these ceramic nanocomposites is explained in terms of cluster model. It is concluded that presence of amorphous Si-C-N(O) clusters are responsible for the limited flowability in these ceramics.

  8. Thickness independent reduced forming voltage in oxygen engineered HfO{sub 2} based resistive switching memories

    SciTech Connect (OSTI)

    Sharath, S. U. Kurian, J.; Komissinskiy, P.; Hildebrandt, E.; Alff, L.; Bertaud, T.; Walczyk, C.; Calka, P.; Schroeder, T.

    2014-08-18

    The conducting filament forming voltage of stoichiometric hafnium oxide based resistive switching layers increases linearly with layer thickness. Using strongly reduced oxygen deficient hafnium oxide thin films grown on polycrystalline TiN/Si(001) substrates, the thickness dependence of the forming voltage is strongly suppressed. Instead, an almost constant forming voltage of about 3?V is observed up to 200?nm layer thickness. This effect suggests that filament formation and switching occurs for all samples in an oxidized HfO{sub 2} surface layer of a few nanometer thickness while the highly oxygen deficient thin film itself merely serves as a oxygen vacancy reservoir.

  9. A Novel Zr-1Nb Alloy and a New Look at Hydriding

    SciTech Connect (OSTI)

    Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

    2013-09-01

    A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys.

  10. Photo-induced tunneling currents in MOS structures with various HfO{sub 2}/SiO{sub 2} stacking dielectrics

    SciTech Connect (OSTI)

    Pang, Chin-Sheng; Hwu, Jenn-Gwo

    2014-04-15

    In this study, the current conduction mechanisms of structures with tandem high-k dielectric in illumination are discussed. Samples of Al/SiO{sub 2}/Si (S), Al/HfO{sub 2}/SiO{sub 2}/Si (H), and Al/3HfO{sub 2}/SiO{sub 2}/Si (3H) were examined. The significant observation of electron traps of sample H compares to sample S is found under the double bias capacitance-voltage (C-V) measurements in illumination. Moreover, the photo absorption sensitivity of sample H is higher than S due to the formation of HfO{sub 2} dielectric layer, which leads to larger numbers of carriers crowded through the sweep of V{sub G} before the domination of tunneling current. Additionally, the HfO{sub 2} dielectric layer would block the electrons passing through oxide from valance band, which would result in less electron-hole (e{sup −}-h{sup +}) pairs recombination effect. Also, it was found that both of the samples S and H show perimeter dependency of positive bias currents due to strong fringing field effect in dark and illumination; while sample 3H shows area dependency of positive bias currents in strong illumination. The non-uniform tunneling current through thin dielectric and through HfO{sub 2} stacking layers are importance to MOS(p) tunneling photo diodes.

  11. Growth and oxidization stability of cubic Zr{sub 1−x}Gd{sub x}N solid solution thin films

    SciTech Connect (OSTI)

    Höglund, C.; Alling, B.; Jensen, J.; Hultman, L.; Birch, J.; Hall-Wilton, R.

    2015-05-21

    We report Zr{sub 1−x}Gd{sub x}N thin films deposited by magnetron sputter deposition. We show a solid solubility of the highly neutron absorbing GdN into ZrN along the whole compositional range, which is in excellent agreement with our recent predictions by first-principles calculations. An oxidization study in air shows that Zr{sub 1−x}Gd{sub x}N with x reaching from 1 to close to 0 fully oxidizes, but that the oxidization is slowed down by an increased amount of ZrN or stopped by applying a capping layer of ZrN. The crystalline quality of Zr{sub 0.5}Gd{sub 0.5}N films increases with substrate temperatures increasing from 100 °C to 900 °C.

  12. Optical and local structural study of Gd doped ZrO{sub 2} thin films deposited by RF magnetron sputtering technique

    SciTech Connect (OSTI)

    Haque, S. Maidul Shinde, D. D.; Misal, J. S.; Jha, S. N.; Bhattacharyya, D.; Sahoo, N. K.

    2015-06-24

    ZrO{sub 2} samples with 0, 7, 9, 11, 13 % Gd doping have been prepared by RF magnetron sputtering deposition technique for solid oxide fuel cell application. The optical properties of the samples have been studied by transmission spectrophotometry and spectroscopic ellipsometry while the local structure surrounding Zr sites has been characterized by extended x-ray absorption fine structure (EXAFS) measurement at Zr K edge with synchrotron radiation. It has been observed that beyond 11% Gd doping, band gap decreases and refractive index increases significantly and also oxygen and Zr coordinations surrounding Zr sites increase which indicates the formation of Gd clustering in ZrO{sub 2} matrix beyond this doping concentration.

  13. Investigation of Zr-doped BSCF perovskite membrane for oxygen separation in the intermediate temperature range

    SciTech Connect (OSTI)

    Ravkina, Olga; Klande, Tobias; Feldhoff, Armin

    2013-05-01

    The series of (Ba?.?Sr?.?)(Co?.?Fe?.?){sub 1z}Zr{sub z}O{sub 3?} (z=0, 0.01, 0.03, 0.05, 0.07, and 0.09) was synthesized by a solgel method. The materials with a zirconium content up to 3 mol% were found to be single phase. Further increase results in formation of a mixed (Ba,Sr)ZrO? by-phase, which was found along the grain boundaries and in the grains. With increasing zirconium content the oxygen permeation flux decreases considerably. The effect of the zirconium substitution on the long-term phase stability was investigated by long-term oxygen permeation experiments and X-ray diffraction. A slight stabilization of the oxygen flux of (Ba?.?Sr{sub 0.5})(Co?.?Fe?.?)?.??Zr?.??O{sub 3?} was found after 180 h at 1023 K. However, all compositions show a decrease in permeation flux with time, but the pure BSCF membrane exhibited the strongest drop after 180 h of operation. The decomposition products of the cubic perovskite phase were found to be a hexagonal Ba{sub 0.5x}Sr{sub 0.5x}CoO? and a rhombohedral Ba{sub 1x}Sr{sub x}Co{sub 2y}Fe{sub y}O{sub 5?}. - Graphical abstract: Backscattered-electron channeling contrast image of BSCF membrane cross-section after long-term oxygen permeation at 1023 K showing different phases in different colors. Highlights: Ba?.?Sr?.?Co?.?Fe?.?O{sub 3?} systematically doped with increasing amount of zirconium. Cubic single-phase materials up to 3 wt% zirconium. Mixed (Ba,Sr)ZrO? by-phase formed mainly in the grain boundaries. Jnecke prism was proposed by XRD and EDXS data. (Ba?.?Sr?.?)(Co?.?Fe?.?)?.??Zr?.??O{sub 3?} showed a slight stabilization of oxygen flux as compared to pure Ba?.?Sr?.?Co?.?Fe?.?O{sub 3?}.

  14. Microstructure–property relationships in a high-strength 51Ni–29Ti–20Hf shape memory alloy

    SciTech Connect (OSTI)

    Coughlin, D. R.; Casalena, L.; Yang, F.; Noebe, R. D.; Mills, M. J.

    2015-09-18

    NiTiHf alloys exhibit remarkable shape memory and pseudoelastic properties that are of fundamental interest to a growing number of industries. In this study, differential scanning calorimetry and isothermal compression tests have revealed that the 51Ni–29Ti–20Hf alloy has useful shape memory properties that include a wide range of transformation temperatures as well as highly stable pseudoelastic behavior. These properties are governed by short-term aging conditions, which may be tailored to control transformation temperatures while giving rise to exceptionally high austenite yield strengths which aid transformation stability. The yield strength of the austenite phase can reach 2.1 GPa by aging for 3hrs at 500°C, while aging for 3hrs at 700°C produced an alloy with an austenite finish temperature (A f ) of 146°C. High-resolution scanning transmission electron microscopy has revealed a new precipitate phase, H-phase, under the homogenized and extruded condition and the aged 3 hrs at 500°C condition, but only the previously identified H-phase precipitate was observed after aging at temperatures of 600°C and 700°C for 3 hrs. Finally, dislocation analysis indicated that plastic deformation of the austenite phase occurred by <100> type slip, similar to that observed in binary NiTi.

  15. Microstructure–property relationships in a high-strength 51Ni–29Ti–20Hf shape memory alloy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Coughlin, D. R.; Casalena, L.; Yang, F.; Noebe, R. D.; Mills, M. J.

    2015-09-18

    NiTiHf alloys exhibit remarkable shape memory and pseudoelastic properties that are of fundamental interest to a growing number of industries. In this study, differential scanning calorimetry and isothermal compression tests have revealed that the 51Ni–29Ti–20Hf alloy has useful shape memory properties that include a wide range of transformation temperatures as well as highly stable pseudoelastic behavior. These properties are governed by short-term aging conditions, which may be tailored to control transformation temperatures while giving rise to exceptionally high austenite yield strengths which aid transformation stability. The yield strength of the austenite phase can reach 2.1 GPa by aging for 3hrsmore » at 500°C, while aging for 3hrs at 700°C produced an alloy with an austenite finish temperature (A f ) of 146°C. High-resolution scanning transmission electron microscopy has revealed a new precipitate phase, H-phase, under the homogenized and extruded condition and the aged 3 hrs at 500°C condition, but only the previously identified H-phase precipitate was observed after aging at temperatures of 600°C and 700°C for 3 hrs. Finally, dislocation analysis indicated that plastic deformation of the austenite phase occurred by <100> type slip, similar to that observed in binary NiTi.« less

  16. Unintentional F doping of SrTiO3(001) etched in HF acid-structure and electronic properties

    SciTech Connect (OSTI)

    Chambers, Scott A.; Droubay, Timothy C.; Capan, Cigdem; Sun, Guangyuan

    2012-02-01

    We show that the HF acid etch commonly used to prepare SrTiO3(001) for heteroepitaxial growth of complex oxides results in a non-negligible level of F doping within the terminal surface layer of TiO2. Using a combination of x-ray photoelectron spectroscopy and scanned angle x-ray photoelectron diffraction, we determine that on average ~ 13% of the O anions in the surface layer are replaced by F, but that F does not occupy O sites in deeper layers. Despite this perturbation to the surface, the Fermi level remains unpinned, and the surface-state density, which determines the amount of band bending, is driven by factors other than F doping. The presence of F at the STO surface is expected to result in lower electron mobilities at complex oxide heterojunctions involving STO substrates because of impurity scattering. Unintentional F doping can be substantially reduced by replacing the HF-etch step with a boil in deionized water, which in conjunction with an oxygen tube furnace anneal, leaves the surface flat and TiO2 terminated.

  17. Features of conduction mechanisms in n-HfNiSn semiconductor heavily doped with a Rh acceptor impurity

    SciTech Connect (OSTI)

    Romaka, V. A.; Rogl, P.; Stadnyk, Yu. V.; Romaka, V. V.; Hlil, E. K.; Krajovskii, V. Ya.; Horyn, A. M.

    2013-09-15

    The crystal structure and electron-density distribution, as well as the energy, kinetic, and magnetic characteristics of n-HfNiSn intermetallic semiconductor heavily doped with a Rh acceptor impurity in the temperature range T = 80-400 K, in the acceptor-concentration range N{sub A}{sup Rh} Almost-Equal-To 9.5 Multiplication-Sign 10{sup 19}-1.9 Multiplication-Sign 10{sup 21} cm{sup -3} (x = 0.005-0.10), and in magnetic fields H {<=} 10 kG are investigated. It is established that doping is accompanied by a simultaneous decrease in concentration, the elimination of donor-type structural defects (to x Almost-Equal-To 0.02), and an increase in the concentration of acceptor-type structural defects (0 < x {<=} 0.10). The dependence of the degree of semiconductor compensation on temperature is revealed. A model of the spatial arrangement of atoms in HfNi{sub 1-x}Rh{sub x}Sn is proposed, and the results of calculating the electron structure based on this model agree with the results of investigations of the kinetic and magnetic characteristics of the semiconductor. The results are discussed within the context of the Shklovskii-Efros model for a heavily doped and compensated semiconductor.

  18. Fluorohydrogenate Cluster Ions in the Gas Phase: Electrospray Ionization Mass Spectrometry of the [1-Ethyl-3-methylimidazolium+][F(HF)2.3] Ionic Liquid

    SciTech Connect (OSTI)

    Gary S. Groenewold; James E. Delmore; Michael T. Benson; Tetsuya Tsuda; Rika Hagiwara

    2013-12-01

    Electrospray ionization of the fluorohydrogenate ionic liquid [1-ethyl-3-methylimidazolium][F(HF)2.3] ionic liquid was conducted to understand the nature of the anionic species as they exist in the gas phase. Abundant fluorohydrogenate clusters were produced; however, the dominant anion in the clusters was [FHF-], and not the fluoride-bound HF dimers or trimers that are seen in solution. Density functional theory (DFT) calculations suggest that HF molecules are bound to the clusters by about 30 kcal/mol. The DFT-calculated structures of the [FHF-]-bearing clusters show that the favored interactions of the anions are with the methynic and acetylenic hydrogen atoms on the imidazolium cation, forming planar structures similar to those observed in the solid state. A second series of abundant negative ions was also formed that contained [SiF5-] together with the imidazolium cation and the fluorohydrogenate anions that originate from reaction of the spray solution with silicate surfaces.

  19. Total ionizing dose effect of γ-ray radiation on the switching characteristics and filament stability of HfOx resistive random access memory

    SciTech Connect (OSTI)

    Fang, Runchen; Yu, Shimeng; Gonzalez Velo, Yago; Chen, Wenhao; Holbert, Keith E.; Kozicki, Michael N.; Barnaby, Hugh

    2014-05-05

    The total ionizing dose (TID) effect of gamma-ray (γ-ray) irradiation on HfOx based resistive random access memory was investigated by electrical and material characterizations. The memory states can sustain TID level ∼5.2 Mrad (HfO{sub 2}) without significant change in the functionality or the switching characteristics under pulse cycling. However, the stability of the filament is weakened after irradiation as memory states are more vulnerable to flipping under the electrical stress. X-ray photoelectron spectroscopy was performed to ascertain the physical mechanism of the stability degradation, which is attributed to the Hf-O bond breaking by the high-energy γ-ray exposure.

  20. Self-organization during growth of ZrN/SiN{sub x} multilayers by epitaxial lateral overgrowth

    SciTech Connect (OSTI)

    Fallqvist, A.; Fager, H.; Hultman, L.; Persson, P. O. Å.; Ghafoor, N.

    2013-12-14

    ZrN/SiN{sub x} nanoscale multilayers were deposited on ZrN seed layers grown on top of MgO(001) substrates by dc magnetron sputtering with a constant ZrN thickness of 40 Å and with an intended SiN{sub x} thickness of 2, 4, 6, 8, and 15 Å at a substrate temperature of 800 °C and 6 Å at 500 °C. The films were investigated by X-ray diffraction, high-resolution scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. The investigations show that the SiN{sub x} is amorphous and that the ZrN layers are crystalline. Growth of epitaxial cubic SiN{sub x}—known to take place on TiN(001)—on ZrN(001) is excluded to the monolayer resolution of this study. During the course of SiN{sub x} deposition, the material segregates to form surface precipitates in discontinuous layers for SiN{sub x} thicknesses ≤6 Å that coalesce into continuous layers for 8 and 15 Å thickness at 800 °C, and for 6 Å at 500 °C. The SiN{sub x} precipitates are aligned vertically. The ZrN layers in turn grow by epitaxial lateral overgrowth on the discontinuous SiN{sub x} in samples deposited at 800 °C with up to 6 Å thick SiN{sub x} layers. Effectively a self-organized nanostructure can be grown consisting of strings of 1–3 nm large SiN{sub x} precipitates along apparent column boundaries in the epitaxial ZrN.

  1. Structural, negative thermal expansion and photocatalytic properties of ZrV{sub 2}O{sub 7}: a comparative study between fibers and powders

    SciTech Connect (OSTI)

    Liu, Qinqin; Yang, Juan; Rong, Xiaoqing; Sun, Xiujuan; Cheng, Xiaonong; Tang, Hua; Li, Haohua

    2014-10-15

    Novel ZrV{sub 2}O{sub 7} microfibers with diameters about 13 ?m were synthesized using a solgel technique. For comparison, ZrV{sub 2}O{sub 7} powders were prepared by the same method. The resultant structures were studied by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The results indicated that both the pure ZrV{sub 2}O{sub 7} microfibers and powders could be synthesized by the solgel technique. The thermal expansion property of the as-prepared ZrV{sub 2}O{sub 7} microfibers and powders was characterized by a thermal mechanical analyzer, both the fibers with cylindrical morphology and irregular powders with average size between 100 and 200 nm showed negative thermal expansion between 150 C and 600 C. The photocatalytic activity of the microfibers was compared to that of powders under UV radiations. The band gap of ZrV{sub 2}O{sub 7} microfibers decreased and its absorption edge exhibited red shift. The microfibers also had a higher surface area compared with the powders, resulting in considerably higher photocatalytic characteristics. The large surface area and the enhanced photocatalytic activity of the ZrV{sub 2}O{sub 7} microfibers also offer potential applications in sensors and inorganic ion exchangers. - Graphical abstract: (a and c) SEM photos of ZrV{sub 2}O{sub 7} powders and fibers. (b and d) TEM images of ZrV{sub 2}O{sub 7} powders and fibers. (e) Thermal expansion curves of ZrV{sub 2}O{sub 7} powders and fibers. (f) Degradation curves of ZrV{sub 2}O{sub 7} powders and ZrV{sub 2}O{sub 7} fibers. - Highlights: Novel ZrV{sub 2}O{sub 7} fibers could be synthesized using solgel technique. ZrV{sub 2}O{sub 7} powders with irregular shape are also prepared for comparison. Both ZrV{sub 2}O{sub 7} microfibers and powders exhibit negative thermal expansion property. ZrV{sub 2}O{sub 7} microfibers show outstanding photocatalytic activity under UV irradiation. This synthesis technique can be

  2. Anisotropy of the solid–liquid interface properties of the Ni–Zr B33 phase from molecular dynamics simulation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wilson, S. R.; Mendelev, M. I.

    2015-01-08

    Solid–liquid interface (SLI) properties of the Ni–Zr B33 phase were determined from molecular dynamics simulations. In order to perform these measurements, a new semi-empirical potential for Ni–Zr alloy was developed that well reproduces the material properties required to model SLIs in the Ni50.0Zr50.0 alloy. In particular, the developed potential is shown to provide that the solid phase emerging from the liquid Ni50.0Zr50.0alloy is B33 (apart from a small fraction of point defects), in agreement with the experimental phase diagram. The SLI properties obtained using the developed potential exhibit an extraordinary degree of anisotropy. It is observed that anisotropies in bothmore » the interfacial free energy and mobility are an order of magnitude larger than those measured to date in any other metallic compound. Moreover, the [0 1 0] interface is shown to play a significant role in the observed anisotropy. Our data suggest that the [0 1 0] interface simultaneously corresponds to the lowest mobility, the lowest free energy and the highest stiffness of all inclinations in B33 Ni–Zr. This finding can be understood by taking into account a rather complicated crystal structure in this crystallographic direction.« less

  3. Transfer couplings and hindrance far below the barrier for 40 Ca + 96 Zr

    SciTech Connect (OSTI)

    Stefanini, A. M.; Montagnoli, G.; Esbensen, H.; Corradi, L.; Courtin, S.; Fioretto, E.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Michelagnoli, C.; Mijatović, T.; Montanari, D.; Pasqualato, G.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Toniolo, N.; Torresi, D.

    2015-01-29

    The sub-barrier fusion excitation function of 40Ca + 96Zr has been measured down to cross sections ≃2.4µb, i.e. two orders of magnitude smaller than obtained in the previous experiment, where the sub-barrier fusion of this system was found to be greatly enhanced with respect to 40Ca + 90Zr, and the need of coupling to transfer channels was suggested. The purpose of this work was to investigate the behavior of 40Ca + 96Zr fusion far below the barrier. The smooth trend of the excitation function has been found to continue, and the logarithmic slope increases very slowly. No indication of hindrance shows up, and a comparison with 48Ca + 96Zr is very useful in this respect. A new CC analysis of the complete excitation function has been performed, including explicitly one- and two-nucleon Q >0 transfer channels. Such transfer couplings bring significant cross section enhancements, even at the level of a few µb. Locating the hindrance threshold, if any, in 40Ca + 96Zr would require challenging measurements of cross sections in the sub-µb range.

  4. Enhancing low-temperature activity and durability of Pd-based diesel oxidation catalysts using ZrO2 supports

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Mi -Young; Kyriakidou, Eleni A.; Choi, Jae -Soon; Toops, Todd J.; Binder, Andrew J.; Thomas, Cyril; Schwartz, Viviane; Chen, Jihua; Hensley, Dale K.; Parks, II, James E.

    2016-01-18

    In this study, we investigated the impact of ZrO2 on the performance of palladium-based oxidation catalysts with respect to low-temperature activity, hydrothermal stability, and sulfur tolerance. Pd supported on ZrO2 and SiO2 were synthesized for a comparative study. Additionally, in an attempt to maximize the ZrO2 surface area and improve sulfur tolerance, a Pd support with ZrO2-dispersed onto SiO2 was studied. The physicochemical properties of the catalysts were examined using ICP, N2 sorption, XRD, SEM, TEM, and NH3-, CO2-, and NOx-TPD. The activity of the Pd catalysts were measured from 60 to 600 °C in a flow of 4000 ppmmore » CO, 500 ppm NO, 1000 ppm C3H6, 4% O2, 5% H2O, and Ar balance. The Pd catalysts were evaluated in fresh, sulfated, and hydrothermally aged states. Overall, the ZrO2-containing catalysts showed considerably higher CO and C3H6 oxidation activity than Pd/SiO2 under the reaction conditions studied.« less

  5. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  6. Zr{sub 9}Co{sub 2}P{sub 4} and Zr{sub 9}Ni{sub 2}P{sub 4}: A new 3D structure type, consisting of edge- and vertex-condensed Zr{sub 6} octahedra

    SciTech Connect (OSTI)

    Kleinke, H.; Franzen, H.F.

    1996-08-28

    The isostructural title compounds were synthesized by arc-melting of stoichiometric ratios of ZrP, Zr, and Co and Ni, respectively, and subsequent annealing at 1450 {degrees}C. Their crystal structure (space group P4/mbm; Zr{sub 9-}Co{sub 2}P{sub 4}, a = 532.23(5) {angstrom}{sup 3}, Z = 2) is derived from a three-dimensional network of Zr{sub 6} octahedra. These octahedra are connected via common vertices to form chains parallel to the c axis and via common edges and vertices in the ab plane, resulting in one double chain and one single chain. Both kinds of the interstitial atoms, the iron-group-metal atom and the phosphorus, are situated in trigonal prismatic holes between these chains, forming short M-P and M-M{prime} bonds. These octahedra can be described as being of the M{sub 6}X{sub 8} cluster type as is also observed in the chalcogenide Chevrel phases. Due to the electronically nonsaturated character of the Zr octahedra and their three-dimensional connectivity, three-dimensional metallic properties are expected for both phosphides, and metallic behavior is confirmed by the observation of Pauli paramagnetism for both compounds.

  7. Modeling of constituent redistribution in U-Pu-Zr metallic fuel.

    SciTech Connect (OSTI)

    Kim, Y. S.; Hofman, G. L.; Hayes, S. L.; Yacout, A. M.; Nuclear Engineering Division; INL

    2006-12-01

    A computer model was developed to analyze constituent redistribution in U-Pu-Zr metallic nuclear fuels. Diffusion and thermochemical properties were parametrically determined to fit the postirradiation data from a fuel test performed in the Experimental Breeder Reactor II (EBR-II). The computer model was used to estimate redistribution profiles of fuels proposed for the conceptual designs of small modular fast reactors. The model results showed that the level of redistribution of the fuel constituents of the designs was similar to the measured data from EBR-II.

  8. Projected shell model study of neutron-rich deformed isotopes of Sr and Zr

    SciTech Connect (OSTI)

    Verma, Sonia; Dar, Parvaiz Ahmad; Devi, Rani [Department of Physics and Electronics, University of Jammu, Jammu-180006 (India)

    2008-02-15

    The projected shell model (PSM) study of {sup 98-102}Sr and {sup 100-104}Zr nuclei is carried out. The reliability of the ground-state wave function is checked by reproducing yrast spectra and electromagnetic properties. The mechanism for the onset of sudden and large deformation at N=60 is worked out. The present piece of research work has unified the two different, or conflicting, early explanations for the onset of deformation at N=60 by the spherical shell model and mean-field theory.

  9. Study of the R-(Zr,W)-(O,N) (R = Y, Nd, Sm, Gd, Yb) oxynitride system

    SciTech Connect (OSTI)

    Tessier, Franck; Maillard, Pascal; Orhan, Emmanuelle; Chevire, Francois

    2010-02-15

    The replacement of tantalum by the couple Zr/W within the RTa-O-N systems (R = Y, Nd, Sm, Gd, Yb), enables the preparation of novel oxide and oxynitride phases in the R-Zr-W-O-N system. R{sub 2}Zr{sub 2-x}W{sub x}O{sub 7+x} oxides exhibit the fluorite-type (x < 0.9) and scheelite (x {approx} 1) structures. Corresponding oxynitride compositions are of the fluorite-type and show different colors, for example in the case of ytterbium: pale yellow (x = 0.2 or 0.25), green (x = 0.5-0.8) and brown for the tungsten-rich samples (x = 0.9, 1). Photocatalytic activity measurements have been performed to investigate the overall water splitting behavior of these colored phases.

  10. SEM in situ MiniCantilever Beam Bending of U-10Mo/Zr/Al Fuel Elements

    SciTech Connect (OSTI)

    Mook, William; Baldwin, Jon K.; Martinez, Ricardo M.; Mara, Nathan A.

    2014-06-16

    In this work, the fracture behavior of Al/Zr and Zr/dU-10Mo interfaces was measured via the minicantilever bend technique. The energy dissipation rates were found to be approximately 3.7-5 mj/mm2 and 5.9 mj/mm2 for each interface, respectively. It was found that in order to test the Zr/U-10Mo interface, location of the hinge of the cantilever was a key parameter. While this test could be adapted to hot cell use through careful alignment fixturing and measurement of crack lengths with an optical microscope (as opposed to SEM, which was used here out of convenience), machining of the cantilevers via MiniMill in such a way as to locate the interfaces at the cantilever hinge, as well as proper placement of a femtosecond laser notch will continue to be key challenges in a hot cell environment.

  11. Structure Analysis of a Precipitate Phase in an Ni-Rich High Temperature NiTiHf Shape Memory Alloy

    SciTech Connect (OSTI)

    Yang, Fan; Coughlin, D. R.; Phillips, Patrick J.; Yang, L.; Devaraj, Arun; Kovarik, Libor; Noebe, Ronald D.; Mills, M. J.

    2013-03-22

    Thermal aging of the high temperature shape memory alloy 50.3Ni-29.7Ti-20Hf (at.%) introduces a novel precipitate phase, which plays an important role in improving shape memory properties. The precipitate phase was investigated by conventional electron diffraction, high resolution scanning transmission electron microscopy (STEM) and three dimensional atom probe tomography. An unrelaxed orthorhombic atomic structural model is proposed based on these observations. This model was subsequently relaxed by ab initio calculations. As a result of the relaxation, atom shuffle displacements occur, which in turn yields improved agreement with the STEM images. The relaxed structure, which is termed the “H-phase”, has also been verified to be thermodymanically stable at 0 K.

  12. In situ study of HfO{sub 2} atomic layer deposition on InP(100)

    SciTech Connect (OSTI)

    Dong, H.; Brennan, B.; Kim, J.; Hinkle, C. L.; Wallace, R. M.; Zhernokletov, D.

    2013-04-29

    The interfacial chemistry of the native oxide and chemically treated InP samples during atomic layer deposition (ALD) HfO{sub 2} growth at 250 Degree-Sign C has been studied by in situ X-ray photoelectron spectroscopy. The In-oxide concentration is seen to gradually decrease on the native oxide and acid etched samples. No significant changes of the P-oxide concentrations are detected, while the P-oxides chemical states are seen to change gradually during the initial cycles of ALD on the native oxide and the chemically treated samples. (NH{sub 4}){sub 2}S treatment strongly decreases In-oxide and P-oxide concentrations prior to ALD and maintains low concentrations during the ALD process.

  13. Set statistics in conductive bridge random access memory device with Cu/HfO{sub 2}/Pt structure

    SciTech Connect (OSTI)

    Zhang, Meiyun; Long, Shibing Wang, Guoming; Xu, Xiaoxin; Li, Yang; Liu, Qi; Lv, Hangbing; Liu, Ming; Lian, Xiaojuan; Miranda, Enrique; Su, Jordi

    2014-11-10

    The switching parameter variation of resistive switching memory is one of the most important challenges in its application. In this letter, we have studied the set statistics of conductive bridge random access memory with a Cu/HfO{sub 2}/Pt structure. The experimental distributions of the set parameters in several off resistance ranges are shown to nicely fit a Weibull model. The Weibull slopes of the set voltage and current increase and decrease logarithmically with off resistance, respectively. This experimental behavior is perfectly captured by a Monte Carlo simulator based on the cell-based set voltage statistics model and the Quantum Point Contact electron transport model. Our work provides indications for the improvement of the switching uniformity.

  14. Distribution of free carriers near heavily-doped epitaxial surfaces of n-type Ge(100) upon HF and HCl treatments

    SciTech Connect (OSTI)

    Park, S. J.; Bolotov, L.; Uchida, N.; Tada, T.

    2015-10-15

    Carrier distributions near n-type epitaxially-grown Ge(100) surfaces with high impurity concentrations (1 × 10{sup 20} cm{sup −3}) were studied using high resolution electron energy loss spectroscopy (HREELS) upon surface treatments in aqueous solutions of HF and HCl. After surface treatments with HCl and HF, the molecular vibration modes distinctly showed either chloride or hydride terminations of Ge surfaces with negligible oxidation. The free-carrier concentration profile was inferred from the conduction band plasmon measurements as a function of the incident electron energies employing a dielectric theory simulation with a 4-layer structure and an effective electron mass of 0.02m{sub 0}. A carrier-free layer of 40 and 24 Å were derived for HCl- and HF-treated Ge(100), respectively. The surface band bending was estimated to be 0.32 eV for HF-treated Ge. HCl-treated Ge surfaces showed a band bending of 0.91 eV attributed to the strong effect of the surface Cl-Ge dipole.

  15. Fundamental science investigations to develop a 6-MV laser triggered gas switch for ZR: first annual report.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Van Den Avyle, James A.; Lehr, Jane Marie; Rose, David; Krompholz, Hermann G.; Vela, Russell; Jorgenson, Roy Eberhardt; Timoshkin, Igor (University of Strathclyde, Glasgow, Scotland); Woodworth, Joseph Ray; Prestwich, Kenneth Randel (Voss Scientific, Albuquerque, NM); Krile, John; Given, Martin (University of Strathclyde, Glasgow, Scotland); McKee, G. Randall; Rosenthal, Stephen Edgar; Struve, Kenneth William; Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Benwell, Andrew L. (University of Missouri-Columbia, Columbia, Missouri); Kovaleski, Scott; LeChien, Keith, R.; Johnson, David (Titan Pulse Sciences Division); Fouracre, R.A. (University of Strathclyde, Glasgow, Scotland); Yeckel, Chris (University of Missouri-Columbia, Columbia, Missouri); Wakeland, Peter Eric; Miller, A. R. (Titan Pulse Sciences Division); Hodge, Keith Conquest (Ktech Corporation, Albuquerque, NM); Pasik, Michael Francis; Savage, Mark Edward; Maenchen, John Eric; Curry, Randy D.; Feltz, Greg; Bliss, David Emery; MacGregor, Scott (University of Strathclyde, Glasgow, Scotland); Corley, J. P. (Ktech Corporation, Albuquerque, NM); Anaya, Victor (Ktech Corporation, Albuquerque, NM); Wallace, Zachariah (Ktech Corporation, Albuquerque, NM); Thoma, Carsten (Voss Scientific, Albuquerque, NM); Neuber, Andreas. (Texas Tech University, Lubbock, TX)

    2007-03-01

    In October 2005, an intensive three-year Laser Triggered Gas Switch (LTGS) development program was initiated to investigate and solve observed performance and reliability issues with the LTGS for ZR. The approach taken has been one of mission-focused research: to revisit and reassess the design, to establish a fundamental understanding of LTGS operation and failure modes, and to test evolving operational hypotheses. This effort is aimed toward deploying an initial switch for ZR in 2007, on supporting rolling upgrades to ZR as the technology can be developed, and to prepare with scientific understanding for the even higher voltage switches anticipated needed for future high-yield accelerators. The ZR LTGS was identified as a potential area of concern quite early, but since initial assessments performed on a simplified Switch Test Bed (STB) at 5 MV showed 300-shot lifetimes on multiple switch builds, this component was judged acceptable. When the Z{sub 20} engineering module was brought online in October 2003 frequent flashovers of the plastic switch envelope were observed at the increased stresses required to compensate for the programmatically increased ZR load inductance. As of October 2006, there have been 1423 Z{sub 20} shots assessing a variety of LTGS designs. Numerous incremental and fundamental switch design modifications have been investigated. As we continue to investigate the LTGS, the basic science of plastic surface tracking, laser triggering, cascade breakdown, and optics degradation remain high-priority mission-focused research topics. Significant progress has been made and, while the switch does not yet achieve design requirements, we are on the path to develop successively better switches for rolling upgrade improvements to ZR. This report summarizes the work performed in FY 2006 by the large team. A high-level summary is followed by detailed individual topical reports.

  16. On stability of self-sustained volume discharge in working mixtures of non-chain electrochemical HF laser

    SciTech Connect (OSTI)

    Belevtsev, A A; Kazantsev, S Yu; Konov, I G; Lebedev, A A; Podlesnykh, S V; Firsov, K N

    2011-08-31

    Burning voltage of a self-sustained volume discharge (SSVD) is studied as a function of the specific energy deposition in SF{sub 5} with C{sub 2}-H{sub 6} and H{sub 2} mixtures, which are working media of a non-chain electrochemical HF laser. It is established that the voltage rises linearly with increasing the specific energy deposition, the relative voltage rise in the SF{sub 6}-C{sub 2}H{sub 6} mixtures being noticeably higher than in pure SF{sub 6} and SF{sub 6}-H{sub 2} mixtures. An assumption is suggested and substantiated on determining the role of molecule dissociation by the electron impact leading to the observed voltage rise. From experimental data we have found approximate energy expenditures of producing dissociation fragments including atomic fluorine in a discharge in pure SF{sub 6}: E-tilde {sub d}(F)= 5{+-}1 eV. The values of E{sub d} well agree with literature data obtained by other experimental methods. A conclusion is drawn that the dissociation process is the main mechanism limiting the current density, which implies SSVD realisation without preliminary gas ionisation in working mixtures of a non-chain HF laser and determines a higher stability of the volume discharge in mixtures of SF{sub 6} with hydrocarbons (deuterocarbons) as compared to mixtures with hydrogen (deuterium). A method is suggested and substantiated for numerical estimation of the limitation effect of the current density and its influence on the SSVD stability. (control of radiation parameters)

  17. Improved high temperature refractory. [MgCr/sub 2/O/sub 4/ composite with ZrO/sub 2/

    DOE Patents [OSTI]

    Singh, J.P.; James, J.; Picciolo, J.J.

    1985-12-10

    A high chromia refractory composite has been developed with improved thermal shock resistance and containing about 5 to 30 wt % of unstabilized ZrO/sub 2/ having a temperature-dependent phase change resulting in large expansion mismatch between the ZrO/sub 2/ and the chromia matrix which causes microcracks to form during cooling in the high chromia matrix. The particle size preferably is primarily between about 0.6 to 5 microns and particularly below about 3 microns with an average size in the order of 1.2 to 1.8 microns.

  18. Ab-initio study of high temperature lattice dynamics of BCC zirconium (β-Zr) and uranium (γ-U)

    SciTech Connect (OSTI)

    Ghosh, Partha S. Arya, A. Dey, G. K.

    2014-04-24

    Using self consistent ab-initio lattice dynamics calculations, we show that bcc structures of Zr and U phases become stable at high temperature by phonon-phonon interactions. The calculated temperature dependent phonon dispersion curve (PDC) of β-Zr match excellently with experimental PDC. But the calculated PDC for γ-U shows negative phonon frequencies even at solid to liquid transition temperature. We show that this discrepancy is due to an overestimation of instability depth of bcc U phase which is removed by incorporation of spin-orbit coupling in the electronic structure calculations.

  19. Diffusional Interaction between U-10 wt.% Zr and Fe at 903K, 923K and 953K (630C, 650C, and 680C)

    SciTech Connect (OSTI)

    Park, K Y.; Huang, K.; Paz y Puente, A.; Lee, H. S.; Sencer, B. H.; Kennedy, J. R.

    2014-04-15

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 903, 923 and 953K for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, ?-U, ?-U, Zr-precipitates, ?, ? and ? were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of ?, ? and ?-phases. The ?, ? and ?-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)2, and I4/mcm(140) U3(Zr,Fe), respectively.

  20. Charge trapping of Ge-nanocrystals embedded in TaZrO{sub x} dielectric films

    SciTech Connect (OSTI)

    Lehninger, D. Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J.; Klemm, V.; Rafaja, D.; Borany, J. von

    2015-01-12

    Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO{sub x} by thermal annealing of co-sputtered Ge-TaZrO{sub x} layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window.

  1. Irradiation performance of U-Pu-Zr metal fuels for liquid-metal-cooled reactors

    SciTech Connect (OSTI)

    Tsai, H.; Cohen, A.B.; Billone, M.C.; Neimark, L.A.

    1994-10-01

    This report discusses a fuel system utilizing metallic U-Pu-Zr alloys which has been developed for advanced liquid metal-cooled reactors (LMRs). Result`s from extensive irradiation testing conducted in EBR-II show a design having the following key features can achieve both high reliability and high burnup capability: a cast nominally U-20wt %Pu-10wt %Zr slug with the diameter sized to yield a fuel smear density of {approx}75% theoretical density, low-swelling tempered martensitic stainless steel cladding, sodium bond filling the initial fuel/cladding gap, and an as-built plenum/fuel volume ratio of {approx}1.5. The robust performance capability of this design stems primarily from the negligible loading on the cladding from either fuel/cladding mechanical interaction or fission-gas pressure during the irradiation. The effects of these individual design parameters, e.g., fuel smear density, zirconium content in fuel, plenum volume, and cladding types, on fuel element performance were investigated in a systematic irradiation experiment in EBR-II. The results show that, at the discharge burnup of {approx}11 at. %, variations on zirconium content or plenum volume in the ranges tested have no substantial effects on performance. Fuel smear density, on the other hand, has pronounced but countervailing effects: increased density results in greater cladding strain, but lesser cladding wastage from fuel/cladding chemical interaction.

  2. ZrN coatings deposited by high power impulse magnetron sputtering and cathodic arc techniques

    SciTech Connect (OSTI)

    Purandare, Yashodhan Ehiasarian, Arutiun; Hovsepian, Papken; Santana, Antonio

    2014-05-15

    Zirconium nitride (ZrN) coatings were deposited on 1??m finish high speed steel and 316L stainless steel test coupons. Cathodic Arc (CA) and High Power Impulse Magnetron Sputtering (HIPIMS) + Unbalanced Magnetron Sputtering (UBM) techniques were utilized to deposit coatings. CA plasmas are known to be rich in metal and gas ions of the depositing species as well as macroparticles (droplets) emitted from the arc sports. Combining HIPIMS technique with UBM in the same deposition process facilitated increased ion bombardment on the depositing species during coating growth maintaining high deposition rate. Prior to coating deposition, substrates were pretreated with Zr{sup +} rich plasma, for both arc deposited and HIPIMS deposited coatings, which led to a very high scratch adhesion value (L{sub C2}) of 100 N. Characterization results revealed the overall thickness of the coatings in the range of 2.5??m with hardness in the range of 3040?GPa depending on the deposition technique. Cross-sectional transmission electron microscopy and tribological experiments such as dry sliding wear tests and corrosion studies have been utilized to study the effects of ion bombardment on the structure and properties of these coatings. In all the cases, HIPIMS assisted UBM deposited coating fared equal or better than the arc deposited coatings, the reasons being discussed in this paper. Thus H+U coatings provide a good alternative to arc deposited where smooth, dense coatings are required and macrodroplets cannot be tolerated.

  3. Determination of the displacement energy of O, Si and Zr under electron beam irradiation

    SciTech Connect (OSTI)

    Edmondson, Philip D; Weber, William J; Namavar, Fereydoon; Zhang, Yanwen

    2012-01-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  4. Determination of the Displacement Energies of O, Si and Zr Under Electron Beam Irradiation

    SciTech Connect (OSTI)

    Edmondson, P. D.; Weber, William J.; Namavar, Fereydoon; Zhang, Yanwen

    2012-03-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to ~1.5 x 10e m has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electronsolid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be ~400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  5. Synthesis of ZrO{sub 2} nanoparticles by hydrothermal treatment

    SciTech Connect (OSTI)

    Machmudah, Siti Widiyastuti, W. Prastuti, Okky Putri Nurtono, Tantular Winardi, Sugeng; Wahyudiono,; Kanda, Hideki; Goto, Motonobu

    2014-02-24

    Zirconium oxide (zirconia, ZrO{sub 2}) is the most common material used for electrolyte of solid oxide fuel cells (SOFCs). Zirconia has attracted attention for applications in optical coatings, buffer layers for growing superconductors, thermal-shield, corrosion resistant coatings, ionic conductors, and oxygen sensors, and for potential applications including transparent optical devices and electrochemical capacitor electrodes, fuel cells, catalysts, and advanced ceramics. In this work, zirconia particles were synthesized from ZrCl{sub 4} precursor with hydrothermal treatment in a batch reactor. Hydrothermal treatment may allow obtaining nanoparticles and sintered materials with controlled chemical and structural characteristics. Hydrothermal treatment was carried out at temperatures of 150 200C with precursor concentration of 0.1 0.5 M. Zirconia particles obtained from this treatment were analyzed by using SEM, PSD and XRD to characterize the morphology, particle size distribution, and crystallinity, respectively. Based on the analysis, the size of zirconia particles were around 200 nm and it became smaller with decreasing precursor concentration. The increasing temperature caused the particles formed having uniform size. Zirconia particles formed by hydrothermal treatment were monoclinic, tetragonal and cubic crystal.

  6. New Insights into Reaction Mechanisms of Ethanol Steam Reforming on Co-ZrO2

    SciTech Connect (OSTI)

    Sun, Junming; Karim, Ayman M.; Mei, Donghai; Engelhard, Mark H.; Bao, Xinhe; Wang, Yong

    2015-01-01

    The reaction pathway of ethanol steam reforming on Co-ZrO2 has been identified and the active sites associated with each step are proposed. Ethanol is converted to acetaldehyde and then to acetone, followed by acetone steam reforming. More than 90% carbon was found to follow this reaction pathway. N2-Sorption, X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR), in situ X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy, as well as theoretical Density Functional Theory (DFT) calculations have been employed to identify the structure and functionality of the catalysts, which was further used to correlate their performance in ESR. It was found that metallic cobalt is mainly responsible for the acetone steam reforming reactions; while, CoO and basic sites on the support play a key role in converting ethanol to acetone via dehydrogenation and condensation/ketonization reaction pathways. The current work provides fundamental understanding of the ethanol steam reforming reaction mechanisms on Co-ZrO2 catalysts and sheds light on the rational design of selective and durable ethanol steam reforming catalysts.

  7. Synthesis and characterization of rare earth doped ZrO{sub 2} nanophosphors

    SciTech Connect (OSTI)

    Agrawal, Sadhana E-mail: jsvikasdubey@gmail.com; Dubey, Vikas E-mail: jsvikasdubey@gmail.com

    2014-10-24

    In this paper, we reports synthesis, characterization and thermoluminescence (TL) glow curves of europium and dysprosium activated zirconium dioxide (ZrO{sub 2}: Eu{sup 3+}, Dy{sup 3+}) phosphor with variable concentration of europium and fixed concentration of dysprosium. The sample was prepared by the Solid state method; thereafter, the TL glow curves were recorded for different concentration of europium with 20 min UV exposure at a heating rate of 6.7C/s. The trapping parameters for synthesized phosphors of ZrO{sub 2}: Eu{sup 3+}, Dy{sup 3+} have been calculated by using a peak shape method. The sample was characterized for structural analysis by XRD (X-ray diffraction) and morphological analysis by FEGSEM (field emission gun scanning electron microscope) and FTIR (Fourier transform infrared spectroscopy). The effect of variable europium concentration and fixed dysprosium concentration on TL studies were interpreted and the formation of trap depth and reproducibility of prepared phosphor were analyzed by TL glow curves. The peak temperature on TL less than 200C shows the formation of deep trapping in prepared sample. The high temperature peak shows the less fading and more stability in prepared sample.

  8. Ordered omega derivatives in (Zr{sub 3}Al)-Nb alloys

    SciTech Connect (OSTI)

    Tewari, R.; Dey, G.K.; Mukhopadhyay, P.; Banerjee, S.; Bendersky, L.A.

    1998-12-31

    Various kinds of phase transformation, viz., spinodal decomposition, omega transformation, precipitation reactions and martensitic transformation can be induced in ternary (Zr{sub 3}Al)-Nb alloys in conditions far removed from equilibrium. Transformation sequences in alloys containing 3% niobium are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the {beta} (bcc) phase and displacive omega and {beta} to {alpha} (hcp) transformations. Microstructures of rapidly solidified alloy showed a distribution of cuboidal (D8{sub 8} phase) particles in the {beta} matrix. The periodic arrangement of these particles along the <100>{sub {beta}} directions was indicative of a spinodal transformation which preceded their formation. The {beta} {r_arrow} D8{sub 8} transformation could be accomplished by the superimposition of three processes, namely, chemical ordering, lattice collapse akin to {omega} transformation and vacancy ordering. During isothermal aging the D8{sub 8} phase transformed into the B8{sub 2} phase. The observed lattice correspondence and transformation morphology suggested that the D8{sub 8} to B8{sub 2} structural change involved the replacement of structural vacancies in the former by zirconium atoms without any reconstitution of the lattice. The evolution of the equilibrium Zr{sub 3}Al (L1{sub 2} structure) phase during prolonged aging were also studied.

  9. Magnetic Force Microscopy Study of Zr2Co11 -Based Nanocrystalline Materials: Effect of Mo Addition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yue, Lanping; Jin, Yunlong; Zhang, Wenyong; Sellmyer, David J.

    2015-01-01

    Tmore » he addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr2Co11-based nanocrystalline permanent magnets. he effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr16Co84-xMox(x=0, 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. he coercivity of the samples increases with the increase in Mo content (x≤1.5). he maximum energy product(BH)maxincreases with increasingxfrom 0.5 MGOe forx=0to a maximum value of 4.2 MGOe forx=1.5. he smallest domain size with a relatively short magnetic correlation length of 128 nm and largest root-mean-square phase shiftΦrmsvalue of 0.66° are observed for thex=1.5. he optimal Mo addition promotes magnetic domain structure refinement and thus leads to a significant increase in coercivity and energy product in this sample.« less

  10. The first mixed-halide zirconium cluster compounds: Zr{sub 6}Cl{sub 1.6}I{sub 10.4}Be, Zr{sub 6}Cl{sub 1.3}I{sub 10.7}B, and Zr{sub 6}Cl{sub 11.5}I{sub 1.5}B. Matrix effects and halogen substitution in compact network structures

    SciTech Connect (OSTI)

    Koeckerling, M.; Qi, R.Y.; Corbett, J.D.

    1996-03-13

    Investigations of the effect of halogen size on structure stability have been conducted in well-reduced and heavily interbridged zirconium chloride-iodide cluster systems. The title compounds are obtained in good yields from reactions of Zr, ZrCl{sub 4}, ZrI{sub 4}, and B or Be in sealed Ta tubes for {approximately} 4 weeks at 850 {degrees}C. Single-crystal diffraction at room temperature established these as Zr{sub 6}Cl{sub 1.65(4)}I{sub 10.35(4)}Be and Zr{sub 6}Cl{sub 1.27/(3)}. These are derivatives of the Zr{sub 6}I{sub 12}C and orthorhombic Zr{sub 6}Cl{sub 13}B structures, respectively, the latter containing unusual linear chains of clusters interbridged by Cl{sup i-i} that are in turn interconnected by three-bonded Cl{sup a-a-a} atoms. The random substitution of fractional Cl at specific I sites in the first two, and I for certain Cl in the third, was positionally resolved in all cases. The replacement always occurs at two-bonded X{sup i}, so that single types of halogen are left in sites that interconnected clusters and generate the three-dimensional array. Structural changes seen in both structures are specifically related to relief of X{hor_ellipsis}X crowding in the parent structure (matrix effects). Substitution of Cl for I{sup i} in the Zr{sub 6}I{sub 12}C type greatly reduces intercluster I{hor_ellipsis}I repulsions and allows, among other things, a 0.20 {Angstrom} (5.8*5) reduction in Zr-I{sup 1-i} intercluster bond lengths. Increased Cl{hor_ellipsis}I repulsions caused by I substitution in orthorhombic Zr{sub 6}Cl{sub 11.5}I{sub 1.5}B. Phase widths found are 0{le} x {le} 1.4 for Zr{sub 6}Cl{sub x}I{sub 12-x}Z (Z=B, Be) and 0 {le} x {le} 1.5 for Zr{sub 6}Cl{sub 13-x}I{sub x}B. The limit for iodine substitution in the chlorine-rich rhombohedral Zr{sub 6}Cl{sub 12-x}I{sub x}Be is about x=2.5.

  11. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Hill, R.N.

    1999-03-23

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both. 7 figs.

  12. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, Douglas C.; Porter, Douglas L.; Hayes, Steven L.; Hill, Robert N.

    1999-01-01

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both.

  13. Broad Temperature Pinning Study of 15 mol.% Zr-Added (Gd, Y)-Ba-Cu-O MOCVD Coated Conductors

    SciTech Connect (OSTI)

    Xu, AX; Khatri, N; Liu, YH; Majkic, G; Galstyan, E; Selvamanickam, V; Chen, YM; Lei, CH; Abraimov, D; Hu, XB; Jaroszynski, J; Larbalestier, D

    2015-06-01

    BaZrO3 (BZO) nanocolumns have long been shown to be very effective for raising the pinning force F-p of REBa2Cu3Ox (REBCO, where RE = rare earth) films at high temperatures and recently at low temperatures too. We have successfully incorporated a high density of BZO nanorods into metal organic chemical vapor deposited (MOCVD) REBCO coated conductors via Zr addition. We found that, compared to the 7.5% Zr-added coated conductor, dense BZO nanorod arrays in the 15% Zr-added conductor are effective over the whole temperature range from 77 K down to 4.2 K. We attribute the substantially enhanced J(c) at 30 K to the weak uncorrelated pinning as well as the strong correlated pinning. Meanwhile, by tripling the REBCO layer thickness to similar to 2.8 mu m, the engineering critical current density J(e) at 30 K exceeds J(e) of optimized Nb-Ti wires at 4.2 K.

  14. Zero added oxygen for high quality sputtered ITO. A data science investigation of reduced Sn-content and added Zr

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Peshek, Timothy J.; Burst, James M.; Coutts, Timothy J.; Gessert, Timothy A.

    2016-01-19

    Here, we demonstrate mobilities of >45 cm2/V s for sputtered tin-doped indium oxide (ITO) films at zero added oxygen. All films were deposited with 5 wt. % SnO2, instead of the more conventional 8–10 wt. %, and had varying ZrO2 content from 0 to 3 wt. %, with a subsequent reduction in In2O3 content. Moreover, these films were deposited by radio-frequency magnetron sputtering from nominally stoichiometric targets with varying oxygen partial pressure in the sputter ambient. Anomalous behavior was discovered for films with no Zr-added, where a bimodality of high and low mobilities was discovered for nominally similar growth conditions.more » However, all films showed the lowest resistivity and highest mobilities when the oxygen partial pressure in the sputter ambient was zero. This result is contrasted with several other reports of ITO transport performance having a maximum for small but nonzero oxygen partial pressure. Our result is attributed to the reduced concentration of SnO2. The addition of ZrO2 yielded the highest mobilities at >55 cm2/V s and the films showed a modest increase in optical transmission with increasing Zr-content.« less

  15. Intrinsic Nanostructure in Zr2-xFe4Si16-y (x=0.81, y=6.06)

    SciTech Connect (OSTI)

    Smith, G J; Simonson, J W; Orvis, T; Marques, C; Grose, J E; Kistner-Morris, J J; Wu, L; Cho, Kyuil; Kim, Hyong june; Tanatar, Makariy A; Garlea, V O; Prozorov, Ruslan; Zhu, Y; Aronson, M C

    2014-09-17

    We present a study of the crystal structure and physical properties of single crystals of a new Fe-based ternary compound, Zr2?x Fe4Si16?y(x=0.81,y=6.06). Zr1.19 Fe4Si9.94 is a layered compound, where stoichiometric ?-FeSi2-derived slabs are separated by Zr-Si planes with substantial numbers of vacancies. High resolution transmission electron microscopy (HRTEM) experiments show that these Zr-Si layers consist of 3.5nm domains where the Zrand Si vacancies are ordered within a supercell sixteen times the volume of the stoichiometric cell. Within these domains, the occupancies of the Zr and Si sites obey symmetry rules that permit only certain compositions, none of which by themselves reproduce the average composition found in x-ray diffraction experiments. Magnetic susceptibility and magnetization measurements reveal a small but appreciable number of magnetic moments that remain freely fluctuating to 1.8K, while neutron diffraction confirms the absence of bulk magnetic order with a moment of 0.2? B or larger down to 1.5K. Electrical resistivity measurements find that Zr1.19Fe4Si9.94 is metallic, and the modest value of the Sommerfeld coefficient of the specific heat ? = C/T suggests that quasi-particle masses are not particularly strongly enhanced. The onset of superconductivity at Tc 6K results in a partial resistive transition and a small Meissner signal, although a bulk-like transition is found in the specific heat. Sharp peaks in the ac susceptibility signal the interplay of the normal skin depth and the London penetration depth, typical of a system in which nano-sized superconducting grains are separated by a on-superconducting host. Ultra low field differential magnetic susceptibility measurements reveal the presence of a surprisingly large number of trace magnetic and superconducting phases, suggesting that the Zr-Fe-Si ternary system could be a potentially rich source of new bulk superconductor.

  16. Effects of Pt and Zr on the oxidation behavior of FeTbCo magneto-optic films: X-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Majumdar, D.; Hatwar, T. K.

    1989-07-01

    We report the effects of Pt and Zr on the oxidation behavior of FeTbCo magneto-optic films. The addition of 10 at. % Pt or Zr increased environmental stability without significantly affecting the magneto-optic properties. X-ray photoelectron spectroscopy was used to study /ital in/ /ital situ/ oxidation of clean FeTbCoPt and FeTbCoZr films under 5/times/10/sup /minus/7/ Torr of oxygen at room temperature. Pt and Zr played different roles in increasing the oxidation resistance of the alloy. In the FeTbCoPt alloy, Pt reduced the oxygen uptake and retarded the oxidation kinetics of Fe. No oxidation of Pt was observed. In the FeTbCoZr alloy, Zr oxidized readily and segregated to the surface to form a protective layer. The Tb/Fe ratio at the surface increased with oxygen exposure in both alloys but at a faster rate in the FeTbCoPt alloy than in the FeTbCoZr alloy.

  17. Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

    SciTech Connect (OSTI)

    Y. Park; J. Yoo; K. Huang; D. D. Keiser, Jr.; J. F. Jue; B. Rabin; G. Moore; Y. H. Sohn

    2014-04-01

    Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45–345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr2 phase was observed to develop adjacent to Zr, and the a-U phase was found between the UZr2 and U10Mo, while the Mo2Zr was found as precipitates mostly within the a-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si)3Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the a-U, Mo2Zr, and UZr2 phases.

  18. A high surface area Zr(IV)-based metal–organic framework showing stepwise gas adsorption and selective dye uptake

    SciTech Connect (OSTI)

    Lv, Xiu-Liang; Tong, Minman; Huang, Hongliang; Wang, Bin; Gan, Lei; Yang, Qingyuan; Zhong, Chongli; Li, Jian-Rong

    2015-03-15

    Exploitation of new metal–organic framework (MOF) materials with high surface areas has been attracting great attention in related research communities due to their broad potential applications. In this work, a new Zr(IV)-based MOF, [Zr{sub 6}O{sub 4}(OH){sub 4}(eddb){sub 6}] (BUT-30, H{sub 2}eddb=4,4′-(ethyne-1,2-diyl)dibenzoic acid) has been solvothermally synthesized, characterized, and explored for gases and dyes adsorptions. Single-crystal X-ray diffraction analysis demonstrates a three-dimensional cubic framework structure of this MOF, in which each Zr{sub 6}O{sub 4}(OH){sub 4} building unit is linked by 12 linear eddb ligands. BUT-30 has been found stable up to 400 °C and has a Brunauer–Emmett–Teller (BET) surface area as high as 3940.6 m{sup 2} g{sup −1} (based on the N{sub 2} adsorption at 77 K) and total pore volume of 1.55 cm{sup 3} g{sup −1}. It is more interesting that this MOF exhibits stepwise adsorption behaviors for Ar, N{sub 2}, and CO{sub 2} at low temperatures, and selective uptakes towards different ionic dyes. - Graphical abstract: A new Zr(IV)-based MOF with high surface area has been synthesized and structurally characterized, which shows stepwise gas adsorption at low temperature and selective dye uptake from solution. - Highlights: • A new Zr-based MOF was synthesized and structurally characterized. • This MOF shows a higher surface area compared with its analogous UiO-67 and 68. • This MOF shows a rare stepwise adsorption towards light gases at low temperature. • This MOF performs selective uptakes towards cationic dyes over anionic ones. • Using triple-bond spacer is confirmed feasible in enhancing MOF surface areas.

  19. Deposition and characterization of zirconium nitride (ZrN) thin films by reactive magnetron sputtering with linear gas ion source and bias voltage

    SciTech Connect (OSTI)

    Kavitha, A.; Kannan, R.; Subramanian, N. Sankara; Loganathan, S.

    2014-04-24

    Zirconium nitride thin films have been prepared on stainless steel substrate (304L grade) by reactive cylindrical magnetron sputtering method with Gas Ion Source (GIS) and bias voltage using optimized coating parameters. The structure and surface morphologies of the ZrN films were characterized using X-ray diffraction, atomic microscopy and scanning electron microscopy. The adhesion property of ZrN thin film has been increased due to the GIS. The coating exhibits better adhesion strength up to 10 N whereas the ZrN thin film with bias voltage exhibits adhesion up to 500 mN.

  20. Effect of cerium incorporation into zirconia on the activity ofCu/ZrO2 for methanol synthesis via CO hydrogenation

    SciTech Connect (OSTI)

    Pokrovski, Konstantin A.; Rhodes, Michael D.; Bell, Alexis T.

    2005-08-24

    The effects of Ce incorporation into ZrO2 on the catalyticperformance of Cu/ZrO2 for the hydrogenation of CO have beeninvestigated. A Ce0.3Zr0.7O2 solid solution was synthesized by forcedhydrolysis at low pH. After calcination at 873 K, XRD and Ramanspectroscopy characterization indicated that the Ce0.3Zr0.7O2 had a t''crystal structure. 1.2 wt percent Cu/Ce0.3Zr0.7O2 exhibited H2consumption peaks at low temperature (<473 K) during H2-TPRindicating a significant fraction (~; 70 percent) of Ce4+ is reduced toCe3+. 1.2 wt percent Cu/Ce0.3Zr0.7O2 is 2.7 times more active formethanol synthesis than 1.2 wt percent Cu/m-ZrO2 at 3.0 MPa attemperatures between 473 and 523 K and exhibits a higher selectivity tomethanol. In-situ infrared spectroscopy shows that, analogous toCu/m-ZrO2, the primary surface species on Cu/Ce0.3Zr0.7O2 during COhydrogenation are formate and methoxide species. A shift in the bandposition of the bridged methoxide species indicated that some of thesegroups were bonded to both Zr4+ and Ce3+ cations. For both catalysts, therate-limiting step for methanol synthesis is the reductive elimination ofmethoxide species. The higher rate of methanol synthesis onCu/Ce0.3Zr0.7O2 relative to Cu/m-ZrO2 was primarily due to a ~; 2.4 timeshigher apparent rate constant, kapp, for methoxide hydrogenation, whichis attributed to the higher surface concentration of H atoms on theformer catalyst. The increased capacity of the Ce-containing catalyst isattributed to interactions of H atoms with Ce-O pairs present at thesurface of the oxide phase.

  1. Compliant ferroelastic domains in epitaxial Pb(Zr,Ti)O{sub 3} thin films

    SciTech Connect (OSTI)

    Feigl, L.; McGilly, L. J.; Sandu, C. S.; Setter, N.

    2014-04-28

    Ordered patterns of highly compliant ferroelastic domains have been created by use of tensile strained epitaxial Pb(Zr,Ti)O{sub 3} thin films, of very low defect density, grown on DyScO{sub 3} substrates. The effect of 180° switching on well-ordered a/c 90° domain patterns is investigated by a combination of transmission electron microscopy, piezoelectric force microscopy, and X-ray diffraction. It is shown that ferroelastic a-domains, having an in-plane polarization, can be created and completely removed on a local level by an out-of-plane electric field. The modifications of the ferroelastic domain pattern can be controlled by varying the parameters used during switching with a piezoresponse force microscope to produce the desired arrangement.

  2. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    SciTech Connect (OSTI)

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows up in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.

  3. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Craciun, D.; Socol, G.; Lambers, E.; McCumiskey, E. J.; Taylor, C. R.; Martin, C.; Argibay, Nicolas; Craciun, V.; Tanner, D. B.

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited undermore » higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.« less

  4. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    SciTech Connect (OSTI)

    Craciun, D.; Socol, G.; Lambers, E.; McCumiskey, E. J.; Taylor, C. R.; Martin, C.; Argibay, Nicolas; Craciun, V.; Tanner, D. B.

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited under higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.

  5. Physicochemical investigations of carbon nanofiber supported Cu/ZrO{sub 2} catalyst

    SciTech Connect (OSTI)

    Din, Israf Ud E-mail: maizats@petronas.com.my; Shaharun, Maizatul S. E-mail: maizats@petronas.com.my; Subbarao, Duvvuri; Naeem, A.

    2014-10-24

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu?ZrO{sub 2}/CNF) were prepared by the sequential deposition precipitation method. The Herringbone type of carbon nanofiber GNF-100 (Graphite nanofiber) was used as a catalyst support. Carbon nanofiber was oxidized to (CNF-O) with 5% and 65 % concentration of nitric acid (HNO{sub 3}). The CNF activated with 5% HNO{sub 3} produced higher surface area which is 155 m{sup 2}/g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N{sub 2} adsorption-desorption. The results showed that increase of HNO{sub 3} concentration reduced the surface area and porosity of the catalyst.

  6. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows upmore » in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.« less

  7. LANL Experience Rolling Zr-Clad LEU-10Mo Foils for AFIP-7

    SciTech Connect (OSTI)

    Hammon, Duncan L.; Clarke, Kester D.; Alexander, David J.; Kennedy, Patrick K.; Edwards, Randall L.; Duffield, Andrew N.; Dombrowski, David E.

    2015-05-29

    The cleaning, canning, rolling and final trimming of Low Enriched Uranium-10 wt. pct. Molybdenum (LEU-10Mo) foils for ATR (Advanced Test Reactor) fuel plates to be used in the AFIP-7 (ATR Full Size Plate In Center Flux Trap Position) experiments are summarized. Six Zr-clad foils were produced from two LEU-10Mo castings supplied to Los Alamos National Laboratory (LANL) by Y-12 National Security Complex. Details of cleaning and canning procedures are provided. Hot- and cold-rolling results are presented, including rolling schedules, images of foils in-process, metallography and local compositions of regions of interest, and details of final foil dimensions and process yield. This report was compiled from the slides for the presentation of the same name given by Duncan Hammon on May 12, 2011 at the AFIP-7 Lessons Learned meeting in Salt Lake City, UT, with Los Alamos National Laboratory document number LA-UR 11-02898.

  8. Phase relations and hardness trends of ZrO[subscript 2] phases at high pressure

    SciTech Connect (OSTI)

    Al-Khatatbeh, Yahya; Lee, Kanani K.M.; Kiefer, Boris

    2010-07-23

    We use high-resolution synchrotron x-ray powder diffraction and density-functional theory (DFT) to investigate the phase stability, equations of state (EOSs), and mechanical hardness of zirconia (ZrO{sub 2}) up to {approx}54 and 160 GPa, respectively. For the equilibrium phase at ambient conditions (MI), we provide an experimental EOS that is comparable to results obtained from room-pressure Brillouin scattering experiments and bulk modulus-volume systematics but different from previous high-pressure experiments. The experimental second-order Birch-Murnaghan EOS parameters of MI-ZrO{sub 2} are: ambient-pressure volume (V{sub 0}) of 35.15({+-}0.03) {angstrom}{sup 3}/f.u. with an ambient-pressure bulk modulus K{sub 0} of 210({+-}28) GPa. For the high-pressure OI phase, we find that the K{sub 0} = 290({+-}11) GPa, which is 19%-32% higher than previously determined, and V{sub 0} = 33.65({+-}0.07) {angstrom}{sup 3}/f.u. The small volume decrease of 3.4% across the MI {yields} OI transition at {approx}10 GPa is associated with a 38% increase in the bulk modulus consistent with our DFT calculations that predict a {approx}36% and 39% increase in K{sub 0} for the generalized gradient and local density approximations, respectively. In contrast to the EOS of MI and OI, we find that our experimental EOS for the high-pressure OII phase is in good agreement with previous measurements. The large volume decrease across the OI {yields} OII phase transition as obtained from both our experiments and calculations is {approx}10%. Our estimates, using scaling relations, indicate that this phase, while dense and quenchable, may have a comparatively low mechanical hardness of {approx} 10 GPa.

  9. Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR.

    SciTech Connect (OSTI)

    Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

    2007-03-01

    We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays.

  10. Formation of the dopant-oxygen vacancy complexes and its influence on the photoluminescence emissions in Gd-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L. G.; Tu, H. L.; Xiong, Y. H.; Du, J.; Wang, J. W.; Huang, G. J.; Xiao, W.

    2014-09-28

    Rare earth doping is widely used to improve the desired properties of high-k dielectric oxides. However, whether rare earth doping can suppress the formation of oxygen vacancies is still debated. By using the first-principles calculations with the generalized gradient approximation and more advanced hybrid functional, we have investigated the structural and electronic properties of the dopant-oxygen vacancy complexes in Gd-doped HfO{sub 2}. Our calculations indicate that the Gd dopants interacting with oxygen vacancies can substantially shift up the V{sub O} energy states towards the conduction band edge. This together with other effects, such as capturing the localized electrons at the oxygen vacancy by Gd dopants and suppressing the randomicity of oxygen vacancy formation, improves the reliability of the devices made from Gd-doped HfO{sub 2}. Based on our calculated results, we have presented an explanation for the experimentally observed decrease of the V{sub O}-related photoluminescence intensities upon Gd doping in HfO{sub 2}.

  11. Effect of Si substrate on interfacial SiO{sub 2} scavenging in HfO{sub 2}/SiO{sub 2}/Si stacks

    SciTech Connect (OSTI)

    Li, Xiuyan, E-mail: xiuyan@adam.t.u-tokyo.ac.jp; Yajima, Takeaki; Nishimura, Tomonori; Nagashio, Kosuke; Toriumi, Akira [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656 (Japan)

    2014-11-03

    The scavenging kinetics of an ultra-thin SiO{sub 2} interface layer (SiO{sub 2}-IL) in an HfO{sub 2}/SiO{sub 2}/Si stack is discussed by focusing on the substrate effect in addition to oxygen diffusion. {sup 18}O tracing experiments demonstrate that the O-atom moves from the SiO{sub 2}-IL to the HfO{sub 2} layer during scavenging. SiO{sub 2}-IL scavenging with various substrates (Si, SiC, and sapphire) has been found to be significantly different, which suggests that the Si in the substrate is also necessary to continuously cause the scavenging. Based on these findings and thermodynamic considerations, a kinetic model where oxygen vacancy (V{sub O}) transferred from the HfO{sub 2} reacts with the SiO{sub 2}, which is in contact with the Si-substrate, is proposed for the SiO{sub 2}-IL scavenging.

  12. /sup 234/U//sup 230/Th ratio as an indicator of redox state, and U, Th and Ra behavior in briney aquifers

    SciTech Connect (OSTI)

    Laul, J.C.; Smith, M.R.; Hubbard, N.

    1985-06-01

    The /sup 234/U//sup 230/Th ratio serves as an in-situ indicator of the redox state in groundwater aquifers. The higher this ratio, the more U there is in the +6 state and thus a lesser reducing environment. Radium is retarded in the shallow aquifer and its sorption is dependent on the CaSO/sub 4/ content and redox state. Relative to Ra, U and Th are highly sorbed. The total retardation factor for Th is approx.1400 and mean sorption time for /sup 228/Th is approx.10 days in the shallow zone. The desorption rate of Ra is significantly slower in the shallow than in the deep aquifer. There is no effect of colloids in brines. 6 refs., 5 figs., 2 tabs.

  13. /sup 234/U//sup 230/Th ratio as an indicator of redox state, and U/sub 2/, Th, and Ra behavior in Briney aquifers

    SciTech Connect (OSTI)

    Laul, J.C.; Smith, M.R.; Hubbard, N.

    1986-01-01

    The /sup 234/U//sup 230/Th ratio serves as an in-situ indicator of the redox state in groundwater aquifers. The higher this ratio, the more U there is in the +6 valance state and thus a less reducing environment. Radium sorption is retarded in the shallow aquifer and is dependent on the CaSO/sub 4/ content and the redox state. Relative to Ra, U and Th are highly sorbed. The total retardation factor for Th is approx. 1400 and mean sorption time for /sup 228/Th is approx. 10 days in the shallow zone. The desorption rate of Ra is significantly slower in the shallow than in the deep aquifer. There is no effect of colloids in brines.

  14. The role of film interfaces in near-ultraviolet absorption and pulsed-laser damage in ion-beam-sputtered coatings based on HfO2/SiO2 thin-film pairs

    SciTech Connect (OSTI)

    Ristau, Detlev; Papernov, S.; Kozlov, A. A.; Oliver, J. B.; Smith, C.; Jensen, L.; Gunster, S.; Madebach, H.

    2015-11-23

    The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO2 and SiO2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO2 single-layer film and for a film containing seven narrow HfO2 layers separated by SiO2 layers. The seven-layer film was designed to have a total optical thickness of HfO2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO2 and SiO2 materials.

  15. The role of film interfaces in near-ultraviolet absorption and pulsed-laser damage in ion-beam-sputtered coatings based on HfO2/SiO2 thin-film pairs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ristau, Detlev; Papernov, S.; Kozlov, A. A.; Oliver, J. B.; Smith, C.; Jensen, L.; Gunster, S.; Madebach, H.

    2015-11-23

    The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO2 and SiO2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO2 single-layer film and for a film containing seven narrow HfO2 layers separated by SiO2 layers. The seven-layer film was designed to have a total optical thickness of HfO2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO2more » film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO2 and SiO2 materials.« less

  16. Comparative studies of dipole polarizabilities in Sr{sup +}, Ba{sup +}, and Ra{sup +} and their applications to optical clocks

    SciTech Connect (OSTI)

    Sahoo, B. K.; Timmermans, R. G. E.; Das, B. P.; Mukherjee, D.

    2009-12-15

    Static dipole polarizabilities are calculated in the ground and metastable states of Sr{sup +}, Ba{sup +} and Ra{sup +} using the relativistic coupled-cluster method. Trends of the electron correlation effects are investigated in these atomic ions. We also estimate the Stark and black-body radiation shifts from these results for these systems for the transitions proposed for the optical frequency standards and compare them with available experimental data.

  17. Action for a Better Community, Inc. … Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009, OAS-RA-11-21

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Examination Report Action for a Better Community, Inc. - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 OAS-RA-11-21 September 2011 Department of Energy Washington, DC 20585 September 30, 2011 MEMORANDUM FOR THE ACTING ASSISTANT SECRETARY FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: Rickey R. Hass Deputy Inspector General for Audits and Inspections Office of Inspector General SUBJECT: INFORMATION: Examination Report on "Action for

  18. People's Equal Action and Community Effort, Inc. Š Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009, OAS-RA-11-20

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    People's Equal Action and Community Effort, Inc. - Weatherization Assistance Program Funds Provided by the American Recovery and Reinvestment Act of 2009 OAS-RA-11-20 September 2011 Department of Energy Washington, DC 20585 September 30, 2011 MEMORANDUM FOR THE ACTING ASSISTANT SECRETARY FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: Rickey R. Hass Deputy Inspector General for Audits and Inspections Office of Inspector General SUBJECT: INFORMATION: Examination Report on "People's Equal

  19. The 12 GeV CEBAF Upgrade Project at Thomas Jefferson National Accelerator Facility, OAS-RA-L-11-13

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    12 GeV CEBAF Upgrade Project at Thomas Jefferson National Accelerator Facility OAS-RA-L-11-13 September 2011 Department of Energy Washington, DC 20585 September 30, 2011 MEMORANDUM FOR THE DEPUTY DIRECTOR FOR SCIENCE PROGRAMS, OFFICE OF SCIENCE DIRECTOR, OFFICE OF RISK MANAGEMENT AND FINANCIAL POLICY, OFFICE OF THE CHIEF FINANCIAL OFFICER FROM: David Sedillo, Director NNSA & Science Audits Division Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The 12 GeV CEBAF

  20. The Department of Energy's Clean Cities Alternative Fuel Vehicle Grant Program Funded under the American Recovery and Reinvestment Act, OAS-RA-12-12

    Office of Environmental Management (EM)

    Audit Report The Advanced Research Projects Agency - Energy OAS-RA-11-11 August 2011 Department of Energy Washington, DC 20585 August 22, 2011 MEMORANDUM FOR THE DIRECTOR, ADVANCED RESEARCH PROJECTS AGENCY - ENERGY FROM: George W. Collard Assistant Inspector General for Audits Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Advanced Research Projects Agency - Energy" BACKGROUND The Advanced Research Projects Agency - Energy (ARPA-E), an agency within the

  1. The Department of Energy's Weatherization Assistance Program Funded under the American Recovery and Reinvestment Act for the Commonwealth of Virginia, OAS-RA-11-14

    Office of Environmental Management (EM)

    Energy Efficiency and Conservation Block Grant Program Funded under the American Recovery and Reinvestment Act for the City of Philadelphia OAS-RA-12-09 April 2012 Department of Energy Washington, DC 20585 April 23, 2012 MEMORANDUM FOR THE ASSISTANT SECRETARY FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: George W. Collard Assistant Inspector General for Audits Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Department of Energy's Energy Efficiency and Conservation

  2. The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Missouri (OAS-RA-11-11)

    Office of Environmental Management (EM)

    Missouri OAS-RA-11-12 August 2011 Department of Energy Washington, DC 20585 August 22, 2011 MEMORANDUM FOR THE ACTING ASSISTANT SECRETARY FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: George W. Collard Assistant Inspector General for Audits Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Missouri" BACKGROUND The Department of Energy's

  3. The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Ohio, OAS-RA-12-13

    Office of Environmental Management (EM)

    Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Ohio OAS-RA-12-13 June 2012 Department of Energy Washington, DC 20585 June 25, 2012 MEMORANDUM FOR THE ASSISTANT SECRETARY, ENERGY EFFICIENCY AND RENEWABLE ENERGY FROM: Rickey R. Hass Deputy Inspector General for Audit Services Office of Inspector General SUBJECT: INFORMATION: Audit Report on "The Department of Energy's Weatherization Assistance Program under the American Recovery and

  4. KCP R.A'S

    National Nuclear Security Administration (NNSA)

  5. Microstructural characterization of a thin film ZrN diffusion barrier in an As-fabricated U7Mo/Al matrix dispersion fuel plate

    SciTech Connect (OSTI)

    Keiser, Dennis D.; Perez, Emmanuel; Wiencek, Tom; Leenaers, Ann; Van den Berghe, Sven

    2015-03-01

    The United States High Performance Research Reactor Fuel Development program is developing low enriched uranium fuels for application in research and test reactors. One concept utilizes U7 wt.% Mo (U7Mo) fuel particles dispersed in Al matrix, where the fuel particles are coated with a 1 ?m-thick ZrN coating. The ZrN serves as a diffusion barrier to eliminate a deleterious reaction that can occur between U7Mo and Al when a dispersion fuel is irradiated under aggressive reactor conditions. To investigate the final microstructure of a physically-vapor-deposited ZrN coating in a dispersion fuel plate after it was fabricated using a rolling process, characterization samples were taken from a fuel plate that was fabricated at 500 C using ZrN-coated U7Mo particles, Al matrix and AA6061 cladding. Scanning electron and transmission electron microscopy analysis were performed. Data from these analyses will be used to support future microstructural examinations of irradiated fuel plates, in terms of understanding the effects of irradiation on the ZrN microstructure, and to determine the role of diffusion barrier microstructure in eliminating fuel/matrix interactions during irradiation. The as-fabricated coating was determined to be cubic-ZrN (cF8) phase. It exhibited a columnar microstructure comprised of nanometer-sized grains and a region of relatively high porosity, mainly near the Al matrix. Small impurity-containing phases were observed at the U7Mo/ZrN interface, and no interaction zone was observed at the ZrN/Al interface. The bonding between the U7Mo and ZrN appeared to be mechanical in nature. A relatively high level of oxygen was observed in the ZrN coating, extending from the Al matrix in the ZrN coating in decreasing concentration. The above microstructural characteristics are discussed in terms of what may be most optimal for a diffusion barrier in a dispersion fuel plate application.

  6. CaO-MgO-Al2O3-SiO2 (CMAS) corrosion of Gd2Zr2O7 and Sm2Zr2O7

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Honglong; Bakal, Ahmet; Zhang, Xingxing; Tarwater, Emily; Sheng, Zhizhi; Fergus, Jeffrey W.

    2016-08-08

    Ceramic thermal barrier coatings are applied to superalloys used in gas turbine engineering to increase the operating temperature and the energy conversion efficiency. However, dust consisting of CaO-MgO-Al2O3-SiO2 (CMAS) from the air can be injected into the engines and corrode the thermal barrier coatings. Lanthanide zirconates are promising materials in thermal barrier coatings due to their low thermal conductivities, good phase stability and good corrosion resistance. However, the corrosion resistance mechanism of CMAS on lanthanide zirconates is still not clearly understood. In this work, the corrosion mechanism of Gd2Zr2O7 and Sm2Zr2O7 in CMAS is studied. Here, the results show thatmore » the CMAS can easily react with lanthanide zirconate thermal barrier coatings to form a dense layer, which can resist further corrosion« less

  7. Brazing ZrO{sub 2} ceramic to Ti6Al4V alloy using NiCrSiB amorphous filler foil: Interfacial microstructure and joint properties

    SciTech Connect (OSTI)

    Cao, J., E-mail: cao_jian@hit.edu.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Song, X.G., E-mail: song_xiaoguohit@yahoo.com.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Li, C., E-mail: li_chun1989@yahoo.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Zhao, L.Y., E-mail: Zhao_ly@163.com [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Feng, J.C., E-mail: feng_jicai@163.com [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2013-07-15

    Reliable brazing of ZrO{sub 2} ceramic and Ti6Al4V alloy was achieved using NiCrSiB amorphous filler foil. The interfacial microstructure of ZrO{sub 2}/Ti6Al4V joints was characterized by scanning electron microscope, energy dispersive spectrometer and micro-focused X-ray diffractometer. The effects of brazing temperature on the interfacial microstructure and joining properties of brazed joints were investigated in detail. Active Ti of Ti6Al4V alloy dissolved into molten filler metal and reacted with ZrO{sub 2} ceramic to form a continuous TiO reaction layer, which played an important role in brazing. Various reaction phases including Ti{sub 2}Ni, Ti{sub 5}Si{sub 3} and ?-Ti were formed in brazed joints. With an increasing of brazing temperature, the TiO layer thickened gradually while the Ti{sub 2}Ni amount reduced. Shear test indicated that brazed joints tend to fracture at the interface between ZrO{sub 2} ceramic and brazing seam or Ti{sub 2}Ni intermetallic layer. The maximum average shear strength reached 284.6 MPa when brazed at 1025 C for 10 min. - Graphical Abstract: Interfacial microstructure of ZrO{sub 2}/TC4 joint brazed using NiCrSiB amorphous filler foil was: ZrO{sub 2}/TiO/Ti{sub 2}Ni + ?-Ti + Ti{sub 5}Si{sub 3}/?-Ti/Widmansttten structure/TC4. - Highlights: Brazing of ZrO{sub 2} ceramic and Ti-6Al-4V alloy was achieved. Interfacial microstructure was TiO/Ti{sub 2}Ni + ? + Ti{sub 5}Si{sub 3}/?/Widmansttten structure. The formation of TiO produced the darkening effect of ZrO{sub 2} ceramic. The highest joining strength of 284.6MPa was obtained.

  8. Hierarchical Na-doped cubic ZrO{sub 2} synthesis by a simple hydrothermal route and its application in biodiesel production

    SciTech Connect (OSTI)

    Lara-Garca, Hugo A.; Romero-Ibarra, Issis C.; Pfeiffer, Heriberto

    2014-10-15

    Hierarchical growth of cubic ZrO{sub 2} phase was successfully synthesized via a simple hydrothermal process in the presence of different surfactants (cationic, non-ionic and anionic) and sodium hydroxide. The structural and microstructural characterizations of different ZrO{sub 2} powders were performed using various techniques, such as X-ray diffraction, transmission electron microscopy, N{sub 2} adsorptiondesorption, scanning electron microscopy and infrared. Results indicated that sodium addition stabilized the cubic ZrO{sub 2} phase by a Na-doping process, independently of the surfactant used. In contrast, microstructural characteristics varied as a function of the surfactant and sodium presence. In addition, water vapor (H{sub 2}O) and carbon dioxide (CO{sub 2}) sorption properties were evaluated on ZrO{sub 2} samples. Results evidenced that sample surface reactivity changed as a function of the sodium content. Finally, this surface reactivity was evaluated on the biodiesel transesterification reaction using the different synthesized samples, obtaining yields of 93%. - Graphical abstract: Hierarchical growth of cubic Na-ZrO{sub 2} phase was synthesized by hydrothermal processes in the presence of surfactants and sodium. Sodium addition stabilized the cubic phase by a Na-doping process, while the microstructural characteristics varied with surfactants. Finally, this surface reactivity was evaluated on the biodiesel transesterification reaction. - Highlights: Cubic-ZrO{sub 2} phase was synthesized via a simple hydrothermal process. ZrO{sub 2} structure and microstructures changed as a function of the surfactant. Cubic-ZrO{sub 2} phase was evaluated on the biodiesel transesterification reaction.

  9. Develop Roll-to-Roll Manufacturing Process of ZrO2 Nanocrystals/Acrylic Nanocomposites for High Refractive Index Applications

    SciTech Connect (OSTI)

    Joshi, Pooran C.; Compton, Brett G.; Li, Jianlin; Jellison, Jr, Gerald Earle; Duty, Chad E; Chen, Zhiyun

    2015-04-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to develop and evaluate ZrO2/acrylic nanocomposite coatings for integrated optoelectronic applications. The formulations engineered to be compatible with roll-to-roll process were evaluated in terms of optical and dielectric properties. The uniform distribution of the ZrO2 nanocrystals in the polymer matrix resulted in highly tunable refractive index and dielectric response suitable for advanced photonic and electronic device applications.

  10. Cs{sub 3}Zr{sub 6}Br{sub 15}Z (Z = C, B): A stuffed rhombohedral perovskite structure of linked clusters

    SciTech Connect (OSTI)

    Qi, Ru-Yi; Corbett, J.D.

    1995-03-29

    The isostructural title compounds are synthesized in good yields form reactions of Zr, ZrBr{sub 4}, CsBr, and Z in sealed Ta tubing for {approximately}3 weeks at 850 {degrees}C. Their single-crystal data refinements established the products as Cs{sub 3.02(7)-}Zr{sub 6}Br{sub 14}C and Cs{sub 3.39(5)}Zr{sub 6}br{sub 15}B (R3c, Z = 6, a = 13.1031 (6), 13.116(1) {angstrom}, c = 35.800(3), 35.980(6) {angstrom}, R(F)/R{sub w} = 5.4/5.9, 5.4/4.4%, respectively). The structure is derived form a three-dimensional [Zr{sub 6}(Z)Br{sub 12}]Br{sub 6/2} network of four-rings (as in ReO{sub 6/2}) twisted into a rhombohedral perovskite analogous to VF{sub 3}. The three necessary Cs{sup +} cations are fractionally distributed over five sites that are far from optimal or common, with either eight asymmetric or only three close bromide neighbors. Refinement of a third Cs{sub 3.18(5)}Zr{sub 6}Br{sub 15}C structure at {minus}50 {degrees}C gave the same result with somewhat smaller positional distributions of the atoms.

  11. Understanding ferromagnetism and optical absorption in 3d transition metal-doped cubic ZrO{sub 2} with the modified Becke-Johnson exchange-correlation functional

    SciTech Connect (OSTI)

    Boujnah, M.; Zaari, H.; El Kenz, A.; Labrim, H.; Benyoussef, A.; Mounkachi, O.

    2014-03-28

    The electronic structure, magnetic, and optical properties in cubic crystalline phase of Zr{sub 1?x}TM{sub x}O{sub 2} (TM?=?V, Mn, Fe, and Co) at x?=?6.25% are studied using density functional theory with the Generalized Gradient Approximation and the modified Becke-Johnson of the exchange-correlation energy and potential. In our calculations, the zirconia is a p-type semiconductor and has a large band gap. We evaluated the possibility of long-range magnetic order for transition metal ions substituting Zr. Our results show that ferromagnetism is the ground state in V, Mn, and Fe-doped ZrO{sub 2} and have a high value of energy in Mn-doped ZrO{sub 2}. However, in Co-doped ZrO{sub 2}, antiferromagnetic ordering is more stable than the ferromagnetic one. The exchange interaction mechanism has been discussed to explain the responsible of this stability. Moreover, it has been found that the V, Mn, and Fe transition metals provide half-metallic properties considered to be the leading cause, responsible for ferromagnetism. Furthermore, the optical absorption spectra in the TM -doped cubic ZrO{sub 2} are investigated.

  12. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Barron, S. C.; Knepper, R.; Walker, N.; Weihs, T. P.

    2011-01-11

    We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates (~1 K/s) using differential scanning calorimetry (DSC) traces to 725ºC. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 105 K/s) inmore » high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (Tmax) are largely independent of foil chemistry at 0.6 ± 0.1 m/s and 1220 ± 50 K, respectively, and that the measured Tmax is more than 200 K lower than predicted adiabatic temperatures (Tad). The difference between Tmax and Tad is explained by the prediction that transformation to the final intermetallic phases occurs after Tmax and results in the release of 20-30 % of the total heat of reaction and a delay in rapid cooling.« less

  13. Iron-stabilized nanocrystalline ZrO{sub 2} solid solutions: Synthesis by combustion and thermal stability

    SciTech Connect (OSTI)

    Legorreta Garcia, Felipe; Resende, Valdirene Gonzaga de; De Grave, Eddy; Peigney, Alain; Barnabe, Antoine; Laurent, Christophe

    2009-06-03

    The synthesis of Fe{sup 3+}-stabilized zirconia by the nitrate/urea combustion route was investigated. Using several characterization techniques, including X-ray diffraction, field-emission-gun scanning electron microscopy and notably Moessbauer spectroscopy, it was possible to determine the appropriate amount of urea that allows to obtain a totally stabilized Zr{sub 0.9}Fe{sub 0.1}O{sub 1.95} solid solution. The nanocrystalline zirconia solid solution is mostly tetragonal, but the presence of the cubic phase could not be ruled out. An in-depth study of the thermal stability in air showed that the Fe{sup 3+} solubility in the stabilized solid solution starts to decrease at about 875 deg. C which results in the formation of hematite (possibly containing some Zr{sup 4+}) at the surface of the zirconia grains and further provokes the progressive transformation into the monoclinic zirconia phase.

  14. In situ observation of defect annihilation in Kr ion-irradiated bulk Fe/amorphous-Fe 2 Zr nanocomposite alloy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yu, K. Y.; Fan, Z.; Chen, Y.; Song, M.; Liu, Y.; Wang, H.; Kirk, M. A.; Li, M.; Zhang, X.

    2014-08-26

    Enhanced irradiation tolerance in crystalline multilayers has received significant attention lately. However, little is known on the irradiation response of crystal/amorphous nanolayers. We report on in situ Kr ion irradiation studies of a bulk Fe96Zr4 nanocomposite alloy. Irradiation resulted in amorphization of Fe2Zr and formed crystal/amorphous nanolayers. α-Fe layers exhibited drastically lower defect density and size than those in large α-Fe grains. In situ video revealed that mobile dislocation loops in α-Fe layers were confined by the crystal/amorphous interfaces and kept migrating to annihilate other defects. This study provides new insights on the design of irradiation-tolerant crystal/amorphous nanocomposites.

  15. Assessment of a mechanistic model in U-Pu-Zr metallic alloy fuel fission-gas behavior simulations

    SciTech Connect (OSTI)

    Yun, D.; Rest, J.; Yacout, A. M.

    2012-07-01

    A mechanistic kinetic rate theory model originally developed for the prediction of fission gas behavior in oxide nuclear fuels under steady-state and transient conditions has been assessed to look at its applicability to model fission gas behavior in U-Pu-Zr metallic alloy fuel. In order to capture and validate the underlying physics for irradiated U-Pu-Zr fuels, the mechanistic model was applied to the simulation of fission gas release, fission gas and fission product induced swelling, and the evolution of the gas bubble size distribution in three different fuel zones: the outer {alpha}-U, the intermediate, and the inner {gamma}-U zones. Due to its special microstructural features, the {alpha}-U zone in U-Pu-Zr fuels is believed to contribute the largest fraction of fission gas release among the different fuel zones. It is shown that with the use of small effective grain sizes, the mechanistic model can predict fission gas release that is consistent with (though slightly lower than) experimentally measured data. These simulation results are comparable to the experimentally measured fission gas release since the mechanism of fission gas transport through the densely distributed laminar porosity in the {alpha}-U zone is analogous to the mechanism of fission gas transport through the interconnected gas bubble porosity utilized in the mechanistic model. Detailed gas bubble size distributions predicted with the mechanistic model in both the intermediate zone and the high temperature {gamma}-U zone of U-Pu-Zr fuel are also compared to experimental measurements from available SEM micrographs. These comparisons show good agreements between the simulation results and experimental measurements, and therefore provide crucial guidelines for the selection of key physical parameters required for modeling these two zones. In addition, the results of parametric studies for several key parameters are presented for both the intermediate zone and the {gamma}-U zone simulations

  16. Diffusion Barrier Selection from Refractory Metals (Zr, Mo and Nb) via Interdiffusion Investigation for U-Mo RERTR Fuel Alloy

    SciTech Connect (OSTI)

    K. Huang; C. Kammerer; D. D. Keiser, Jr.; Y. H. Sohn

    2014-04-01

    U-Mo alloys are being developed as low enrichment monolithic fuel under the Reduced Enrichment for Research and Test Reactor (RERTR) Program. Diffusional interactions between the U-Mo fuel alloy and Al-alloy cladding within the monolithic fuel plate construct necessitate incorporation of a barrier layer. Fundamentally, a diffusion barrier candidate must have good thermal conductivity, high melting point, minimal metallurgical interaction, and good irradiation performance. Refractory metals, Zr, Mo, and Nb are considered based on their physical properties, and the diffusion behavior must be carefully examined first with U-Mo fuel alloy. Solid-to-solid U-10wt.%Mo vs. Mo, Zr, or Nb diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 degrees C for various times. The interdiffusion microstructures and chemical composition were examined via scanning electron microscopy and electron probe microanalysis, respectively. For all three systems, the growth rate of interdiffusion zone were calculated at 1000, 900 and 800 degrees C under the assumption of parabolic growth, and calculated for lower temperature of 700, 600 and 500 degrees C according to Arrhenius relationship. The growth rate was determined to be about 10 3 times slower for Zr, 10 5 times slower for Mo and 10 6 times slower for Nb, than the growth rates reported for the interaction between the U-Mo fuel alloy and pure Al or Al-Si cladding alloys. Zr, however was selected as the barrier metal due to a concern for thermo- mechanical behavior of UMo/Nb interface observed from diffusion couples, and for ductile-to-brittle transition of Mo near room temperature.

  17. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    SciTech Connect (OSTI)

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) and Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.

  18. Efficient photoluminescence of Dy{sup 3+} at low concentrations in nanocrystalline ZrO{sub 2}

    SciTech Connect (OSTI)

    Diaz-Torres, L.A.; Rosa, E. de la Salas, P.; Romero, V.H.; Angeles-Chavez, C.

    2008-01-15

    Nanocrystalline ZrO{sub 2}:Dy{sup 3+} were prepared by sol-gel and the structural and photoluminescence properties characterized. The crystallite size ranges from 20 to 50 nm and the crystalline phase is a mixture of tetragonal and monoclinic structure controlled by dopant concentration. Strong white light produced by the host emission band centered at {approx}460 nm and two strong Dy{sup 3+} emission bands, blue (488 nm) and yellow (580 nm), under direct excitation at 350 nm were observed. The highest efficiency was obtained for 0.5 mol% of Dy{sup 3+}. Emission is explained in terms of high asymmetry of the host suggesting that Dy{sup 3+} are substituted mainly into Zr{sup 4+} lattice sites at the crystallite surface. Luminescence quenching is explained in terms of cross-relaxation of intermediate Dy{sup 3+} levels. - Graphical abstract: White light emission from {approx}70 nm ZrO{sub 2}:Dy{sup 3+} nanocrystals. The highest efficiency was obtained for 0.5 mol% of dopant and the dominant crystalline structure was monoclinic.

  19. Homogeneous hydride formation path in α-Zr: Molecular dynamics simulations with the charge-optimized many-body potential

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Yongfeng; Bai, Xian-Ming; Yu, Jianguo; Tonks, Michael R.; Noordhoek, Mark J.; Phillpot, Simon R.

    2016-06-01

    A formation path for homogeneous γ hydride formation in hcp α-Zr, from solid solution to the ζ and then the γ hydride, was demonstrated using molecular static calculations and molecular dynamic simulations with the charge-optimized many-body (COMB) potential. Hydrogen has limited solubility in α-Zr. Once the solubility limit is exceeded, the stability of solid solution gives way to that of coherent hydride phases such as the ζ hydride by planar precipitation of hydrogen. At finite temperatures, the ζ hydride goes through a partial hcp-fcc transformation via 1/3 <1¯100> slip on the basal plane, and transforms into a mixture of γmore » hydride and α-Zr. In the ζ hydride, slip on the basal plane is favored thermodynamically with negligible barrier, and is therefore feasible at finite temperatures without mechanical loading. The transformation process involves slips of three equivalent shear partials, in contrast to that proposed in the literature where only a single shear partial was involved. The adoption of multiple slip partials minimizes the macroscopic shape change of embedded hydride clusters and the shear strain accumulation in the matrix, and thus reduces the overall barrier needed for homogeneous γ hydride formation. In conclusion, this formation path requires finite temperatures for hydrogen diffusion without mechanical loading. Therefore, it should be effective at the cladding operating conditions.« less

  20. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) andmore » Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.« less

  1. Effect of Gd and Zr co-substitution on multiferroic properties of BiFeO{sub 3}

    SciTech Connect (OSTI)

    Arora, Manisha Sati, Prakash Chandra Kumar, Manoj

    2014-04-24

    Single phase Bi{sub 1−x}Gd{sub x}Fe{sub 1−y}Zr{sub y}O{sub 3} (x=0.06;y=0, x= 0.10, y=0 and x=0.10,y= 0.03) nanoparticles were prepared to study the combined effect of Gd and Zr substitution on structural, magnetic and optical properties of BiFeO3. Rietveld refinement of X-ray diffraction patterns predicted that sample with x=0.06, y=0 was indexed to rhombohedral structure while samples with x=0.10, y=0 and x=0.10, y=0.03 were crystallized in multiphase (rhombohedral + orthorhombic). Magnetic properties were significantly enhanced with increasing concentration of Gd ions, however, magnetization reduced slightly with addition of 3% Zr ions in the system. Electron spin Resonance analysis indicated that breaking of spin cycloid is the main reason for enhancement of magnetization. Optical properties were investigated and direct band gap was found for all the samples.

  2. As-cast microstructures in U-Pu-Zr alloy fuel pins with 5-8 wt% minor actinides and 0-1.5 wt% rare-earth elements

    SciTech Connect (OSTI)

    Dawn E. Janney; J. Rory Kennedy

    2010-11-01

    The Idaho National Laboratory (INL) is investigating U–Pu–Zr alloys with low concentrations of minor actinides (Np and Am) and rare-earth elements (La, Ce, Pr, and Nd) as possible nuclear fuels to be used to transmute minor actinides. Alloys with compositions 60U–20Pu– 3Am–2Np–15Zr, 42U–30Pu–5Am–3Np–20Zr, 59U–20Pu–3Am–2Np–1RE–15Zr, 58.5U–20Pu– 3Am–2Np–1.5RE–15Zr, 41U–30Pu–5Am–3Np–1RE–20Zr, and 40.5U–30Pu–5Am–3Np–1.5RE– 20Zr (where numbers represent weight percents of each element and RE is a rare-earth alloy consisting of 6% La, 16% Pr, 25% Ce, and 53% Nd by weight) were arc-melted and vacuum cast as fuel pins approximately 4 mmin diameter. The as-cast pins were sectioned, polished, and examined by scanning electron microscopy. Each alloy contains high-Zr inclusions surrounded by a high-actinide matrix. Alloys with rare-earth elements also contain inclusions that are high in these elements. Within the matrix, concentrations of U and Zr vary inversely, while concentrations of Np and Pu appear approximately constant. Am occurs in the matrix and with some high-rare-earth inclusions, and occasionally as high-Am inclusions in samples without rare-earth elements.

  3. Wettability of brazing alloys on molybdenum and TZM (Mo-Ti-Zr alloy)

    SciTech Connect (OSTI)

    McDonald, M.M.; Keller, D.L.; Heiple, C.R.; Hofmann, W.E.

    1988-01-01

    Vacuum brazing studies have been performed on molybdenum and TZM (0.5Ti-0.08Zr-Mo). Wettability tests have been conducted for nineteen braze metal filler alloys on molybdenum and thirty-two braze metal filler alloys on TZM over a wide range of temperatures. A wetting index, which is a function of contact angle and braze alloy contact area, was determined for each filler alloy at each brazing temperature. The nature and extent of interaction between the brazing alloys and the base metals was analyzed by conventional metallography, scanning-electron microscopy, and electron microprobe analysis. A comparison is made between the behavior of filler alloys on molybdenum and TZM -- filler alloys consistently exhibited less wettability on TZM than on molybdenum. The lower wettability of TZM is believed to be due to a small amount of titanium in the surface oxide on TZM. Cracking was observed in the base metal under some of the high temperature braze deposits. The cracking is shown to arise from liquid metal embrittlement from nickel in the high temperature braze alloys. 7 refs., 11 figs., 2 tabs.

  4. Microstructure and Mechanical Properties of Laves Phase-strengthened Fe-Cr-Zr Alloys

    SciTech Connect (OSTI)

    Tan, Lizhen; Yang, Ying

    2014-12-05

    Laves phase-reinforced alloys have shown some preliminary promising performance at room temperatures. This paper aims at evaluating mechanical properties of Laves phase-strengthened alloys at elevated temperatures. Three Fe-Cr-Zr alloys were designed to favor the formation of eutectic microstructures containing Laves and body-centered cubic phases with the aid of thermodynamic calculations. Microstructural characterization was carried out on the alloys in as-processed and aged states using optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The effect of thermal aging and alloy composition on microstructure has been discussed based on microstructural characterization results. Mechanical properties have been evaluated by means of Vickers microhardness measurements, tensile testing at temperatures up to 973.15 K (700.15 °C), and creep testing at 873.15 K (600.15 °C) and 260 MPa. Alloys close to the eutectic composition show significantly superior strength and creep resistance compared to P92. Finally, however, their low tensile ductility may limit their applications at relatively low temperatures.

  5. Elastic Properties of the Solid Electrolyte Li7La3Zr2O12 (LLZO)

    SciTech Connect (OSTI)

    Yu, Seungho; Schmidt, Robert D.; Garcia-mendez, Regina; Herbert, Erik G.; Dudney, Nancy J.; Wolfenstine, Jeff; Sakamoto, Jeff; Seigel, Donald

    2015-12-16

    The oxide known as LLZO, with nominal composition Li7La3Zr2O12, is a promising solid electrolyte for Li-based batteries due to its high Li-ion conductivity and chemical stability with respect to lithium. Solid electrolytes may also enable the use of metallic Li anodes by serving as a physical barrier that suppresses dendrite initiation and propagation during cycling. Prior linear elasticity models of the Li electrode/solid electrolyte interface suggest that the stability of this interface is highly dependent on the elastic properties of the solid separator. For example, dendritic suppression is predicted to be enhanced as the electrolyte s shear modulus increases. In the present study a combination of first-principles calculations, acoustic impulse excitation measurements, and nanoindentation experiments are used to determine the elastic constants and moduli for highconductivity LLZO compositions based on Al and Ta doping. The calculated and measured isotropic shear moduli are in good agreement and fall within the range of 56-61 GPa. These values are an order of magnitude larger than that for Li metal and far exceed the minimum value ( 8.5 GPa) believed to be necessary to suppress dendrite initiation. These data suggest that LLZO exhibits sufficient stiffness to warrant additional development as a solid electrolyte for Li batteries.

  6. Formation of a shock deformation induced {omega} phase in Zr 20 Nb alloy

    SciTech Connect (OSTI)

    Dey, G.K.; Tewari, R.; Banerjee, S. . E-mail: sbanerji@magnum.barc.ernet.in; Jyoti, G.; Gupta, S.C.; Joshi, K.D.; Sikka, S.K.

    2004-10-18

    The formation of a plate shaped {omega} phase in Zr-Nb alloy after shock deformation has been studied with a view to ascertaining the nature of this transformation. The orientation relationship between the {beta} and the {omega} lattices was {l_brace}111{r_brace}{sub {beta}}//(0001){sub {omega}} and <11-bar 0>{beta}//<112-bar 0>{omega} which is identical to that seen in case of {omega} phase forming in this alloy on thermal treatment. The experimentally determined habit plane of the plate shaped {omega} phase has been compared with that predicted from the phenomenological theory of martensite formation. A mechanism of transformation involving shear on the <112> planes has been considered. The importance of mechanical instability of the {beta} phase in bringing about this transformation has been investigated. The mechanism of initiation of {omega} transformation has been ascertained by high resolution electron microscopy (HREM) of the {beta} lattice and compared with that happening during {omega} formation in the same alloy by thermal treatment.

  7. Accelerated development of Zr-containing new generation ferritic steels for advanced nuclear reactors

    SciTech Connect (OSTI)

    Tan, Lizhen; Yang, Ying; Sridharan, K.

    2015-12-01

    The mission of the Nuclear Energy Enabling Technologies (NEET) program is to develop crosscutting technologies for nuclear energy applications. Advanced structural materials with superior performance at elevated temperatures are always desired for nuclear reactors, which can improve reactor economics, safety margins, and design flexibility. They benefit not only new reactors, including advanced light water reactors (LWRs) and fast reactors such as the sodium-cooled fast reactor (SFR) that is primarily designed for management of high-level wastes, but also life extension of the existing fleet when component exchange is needed. Developing and utilizing the modern materials science tools (experimental, theoretical, and computational tools) is an important path to more efficient alloy development and process optimization. The ultimate goal of this project is, with the aid of computational modeling tools, to accelerate the development of Zr-bearing ferritic alloys that can be fabricated using conventional steelmaking methods. The new alloys are expected to have superior high-temperature creep performance and excellent radiation resistance as compared to Grade 91. The designed alloys were fabricated using arc-melting and drop-casting, followed by hot rolling and conventional heat treatments. Comprehensive experimental studies have been conducted on the developed alloys to evaluate their hardness, tensile properties, creep resistance, Charpy impact toughness, and aging resistance, as well as resistance to proton and heavy ion (Fe2+) irradiation.

  8. Structure and Stoichiometry in Supervalent Doped Li7La3 Zr2O12

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mukhopadhyay, Saikat; Thompson, Travis; Sakamoto, Jeff; Huq, Ashfia; Wolfenstine, Jeff; Allen, Jan L.; Bernstein, Noam; Stewart, Derek A.; Johannes, M. D.

    2015-04-20

    The oxide garnet material Li7La3 Zr2O12 shows remarkably high ionic conductivity when doped with supervalent ions that are charge compensated by Li vacancies and is currently one of the best candidates for development of a technologically relevant solid electrolyte. Determination of optimal dopant concentration, however, has remained a persistent problem due to the extreme difficulty of establishing the actual (as compared to nominal) stoichiometry of intentionally doped materials and by the fact that it is still not entirely clear what level of lattice expansion/contraction best promotes. ionic diffusion. By combining careful synthesis, neutron diffraction, high-resolution X-ray diffraction (XRD), Raman measurements,more » and density functional theory calculations, we show that structure and stoichiometry are intimately related such that the former can in many cases be used as a gauge of the latter. We show that different Li-vacancy creating supervalent ions (Al3+ vs Ta5+) affect the structure very differently, both in terms of the lattice constant, which is easily measurable, and hi terms of the local structure, which can be difficult or impossible to access experimentally but may have important ramifications for conduction. We carefully correlate the lattice constant to dopant type/concentration via Vegard's law and then further correlate these quantities to relevant local structural parameters. In conclusion, our work opens the possibility of developing a codopant scheme that optimizes the Li vacancy concentration and the lattice size simultaneously.« less

  9. Elastic Properties of the Solid Electrolyte Li7La3Zr2O12 (LLZO)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yu, Seungho; Schmidt, Robert D.; Garcia-mendez, Regina; Herbert, Erik G.; Dudney, Nancy J.; Wolfenstine, Jeff; Sakamoto, Jeff; Seigel, Donald

    2015-12-16

    The oxide known as LLZO, with nominal composition Li7La3Zr2O12, is a promising solid electrolyte for Li-based batteries due to its high Li-ion conductivity and chemical stability with respect to lithium. Solid electrolytes may also enable the use of metallic Li anodes by serving as a physical barrier that suppresses dendrite initiation and propagation during cycling. Prior linear elasticity models of the Li electrode/solid electrolyte interface suggest that the stability of this interface is highly dependent on the elastic properties of the solid separator. For example, dendritic suppression is predicted to be enhanced as the electrolyte s shear modulus increases. Inmore » the present study a combination of first-principles calculations, acoustic impulse excitation measurements, and nanoindentation experiments are used to determine the elastic constants and moduli for highconductivity LLZO compositions based on Al and Ta doping. The calculated and measured isotropic shear moduli are in good agreement and fall within the range of 56-61 GPa. These values are an order of magnitude larger than that for Li metal and far exceed the minimum value ( 8.5 GPa) believed to be necessary to suppress dendrite initiation. These data suggest that LLZO exhibits sufficient stiffness to warrant additional development as a solid electrolyte for Li batteries.« less

  10. Prediction of magnetic moment collapse in ZrFe{sub 2} under hydrostatic pressure

    SciTech Connect (OSTI)

    Zhang, Wenxu; Zhang, Wanli

    2015-04-28

    Electronic structure and magnetic properties of ZrFe{sub 2} in the cubic Laves phase are investigated by calculations based on density functional theory. The magnetic moment decreases with the increase of the hydrostatic pressure in an unusual way: Two-step magnetic collapse is predicted. The first one is a continuous change from 1.53??{sub B}/Fe to 0.63??{sub B}/Fe at about 3.6?GPa, and the other is from 0.25??{sub B}/Fe to the nonmagnetic state at about 15?GPa in a first order manner under the local spin density approximation of the exchange correlation potential. A metastable state with intermediate spin moment about 0.15??{sub B}/Fe may exist before that. We understand this process by the changes of density of states during it. The magnetic moment decreases under the pressure in the vicinity of the experimental lattice constant with dlnm/dp=?0.038 GPa{sup ?1}. The spontaneous volume magnetostriction is 3.6%, which is huge enough to find potential applications in magnetostriction actuators and sensors. We suggest that the Invar effect of this compound may be understood when considering the magnetic moment variation according to the magnetostrictive model of Invar.

  11. Synthesis, crystal structure, and properties of the rhombohedral modification of the thiospinel CuZr{sub 1.86(1)}S{sub 4}

    SciTech Connect (OSTI)

    Dong, Yongkwan; McGuire, Michael A.; Yun, Hoseop; DiSalvo, Francis J.

    2010-03-15

    The rhombohedral modification of the thiospinel, CuZr{sub 1.86(1)}S{sub 4}, has been synthesized by the reaction of the constituent elements in an alkali metal halide flux and structurally characterized by single crystal X-ray diffraction techniques. The title compound crystallizes in the rhombohedral space group D{sub 3d}{sup 5}-R3-barm (no. 166, a=7.3552(2) A, c=35.832(2) A, V=1678.76(13) A{sup 3}, Z=12, and R/wR=0.0239/0.0624). The structure is composed of close packed S layers, with a stacking order of ...ABCBCABABCACAB....along the c axis. The Zr and Cu atoms occupy the octahedral and tetrahedral holes between S layers, respectively. Three different kinds of S-M-S layers exist in the structure: layer I has fully occupied Zr and Cu sites, layer II has fully occupied Zr sites but no Cu, and layer III has partially occupied Zr and fully occupied Cu sites. Transport and optical properties indicate that the title compound is a small band gap (1.26 eV) n-type semiconductor. - Graphical abstract: The projected view of the rhombohedral modification, CuZr{sub 1.86(1)}S{sub 4}, down the [100] direction. Large letters denote the packing sequence of the S atoms (yellow circles) along the c axis. Zr (black circles) and Cu (red circles) atoms occupy the octahedral and tetrahedral holes, respectively, between close packed S layers.

  12. Simulation study of HEMT structures with HfO{sub 2} cap layer for mitigating inverse piezoelectric effect related device failures

    SciTech Connect (OSTI)

    Nagulapally, Deepthi; Joshi, Ravi P.; Pradhan, Aswini

    2015-01-15

    The Inverse Piezoelectric Effect (IPE) is thought to contribute to possible device failure of GaN High Electron Mobility Transistors (HEMTs). Here we focus on a simulation study to probe the possible mitigation of the IPE by reducing the internal electric fields and related elastic energy through the use of high-k materials. Inclusion of a HfO{sub 2} “cap layer” above the AlGaN barrier particularly with a partial mesa structure is shown to have potential advantages. Simulations reveal even greater reductions in the internal electric fields by using “field plates” in concert with high-k oxides.

  13. Looking for footprint of bulk metallic glass in electronic and phonon heat capacities of Cu{sub 55}Hf{sub 45?x}Ti{sub x} alloys

    SciTech Connect (OSTI)

    Remenyi, G.; Biljakovi?, K.; Stareini?, D.; Dominko, D.; Risti?, R.; Babi?, E.; Figueroa, I. A.; Davies, H. A.

    2014-04-28

    We report on the heat capacity investigation of Cu{sub 55}Hf{sub 45?x}Ti{sub x} metallic glasses. The most appropriate procedure to estimate low temperature electronic and phonon contributions has been determined. Both contributions exhibit monotonous Ti concentration dependence, demonstrating that there is no relation of either the electron density of states at the Fermi level or the Debye temperature to the increased glass forming ability in the Ti concentration range x?=?1530. The thermodynamic parameters (e.g., reduced glass temperature) remain better indicators in assessing the best composition for bulk metallic glass formation.

  14. Negative effect of crystallization on the mechanism of laser damage in a HfO{sub 2}/SiO{sub 2} multilayer

    SciTech Connect (OSTI)

    Tateno, Ryo; Okada, Hajime; Otobe, Tomohito; Kawase, Keigo; Koga, James K.; Kosuge, Atsushi; Nagashima, Keisuke; Sugiyama, Akira; Kashiwagi, Kunihiro

    2012-12-15

    Elucidation of the mechanisms of laser damage is indispensable in realizing high resistance mirrors for the next generation of ultra-short pulse high intensity lasers. In this study, the surface and a section of the laser-damaged area of a laser mirror were observed with a laser microscope and a transmission electron microscope (cross-sectional TEM), respectively. A grain boundary of HfO{sub 2} microcrystal was observed in the damaged area. This observation and an evaluation of the mirror's damage resistance showed that the formation of crystals in the multilayer mirror is one of the major determinants of damage resistance.

  15. Band alignment of HfO{sub 2}/multilayer MoS{sub 2} interface determined by x-ray photoelectron spectroscopy: Effect of CHF{sub 3} treatment

    SciTech Connect (OSTI)

    Liu, Xinke; He, Jiazhu; Tang, Dan; Jia, Fang; Lu, Youming Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun; Liu, Qiang; Wen, Jiao; Yu, Wenjie; Pan, Jisheng; He, Zhubing; Ang, Kah-Wee

    2015-09-07

    The energy band alignment between HfO{sub 2}/multilayer (ML)-MoS{sub 2} was characterized using high-resolution x-ray photoelectron spectroscopy. The HfO{sub 2} was deposited using an atomic layer deposition tool, and ML-MoS{sub 2} was grown by chemical vapor deposition. A valence band offset (VBO) of 1.98 eV and a conduction band offset (CBO) of 2.72 eV were obtained for the HfO{sub 2}/ML-MoS{sub 2} interface without any treatment. With CHF{sub 3} plasma treatment, a VBO and a CBO across the HfO{sub 2}/ML-MoS{sub 2} interface were found to be 2.47 eV and 2.23 eV, respectively. The band alignment difference is believed to be dominated by the down-shift in the core level of Hf 4d and up-shift in the core level of Mo 3d, or the interface dipoles, which caused by the interfacial layer in rich of F.

  16. The Department of Energy's Management of the Award of a $150 Million Recovery Act Grant to LG Chem Michigan Inc., OAS-RA-13-10

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Management of the Award of a $150 Million Recovery Act Grant to LG Chem Michigan Inc. OAS-RA-13-10 February 2013 Department of Energy Washington, DC 20585 February 8, 2013 MEMORANDUM FOR THE UNDER SECRETARY OF ENERGY FROM: Gregory H. Friedman Inspector General SUBJECT: INFORMATION: Special Report on "The Department of Energy's Management of the Award of a $150 Million Recovery Act Grant to LG Chem Michigan Inc." BACKGROUND The Department of Energy's Vehicle Technologies Program was

  17. Excitation functions of the natTa(p,x)178m2Hf and natW(p,x)178m2Hf reactions at energies up to 2600 MeV

    SciTech Connect (OSTI)

    Titarenko, Yu. E.; Batyaev, V. F.; Pavlov, K. V.; Titarenko, A. Yu.; Zhivun, V. M.; Chauzova, M. V.; Ignatyuk, A. V.; Mashnik, Stepan Georgievich; Leray, S.; Boudard, A.; David, J. -C.; Mancusi, D.; Cugnon, J.; Yariv, Y.; Nishihara, K.; Matsuda, N.; Kumawat, H.; Stankovskiy, A. Yu.

    2015-04-29

    Due to potential level of energy intensity 178m2Hf is an extremely interesting isomer. One possible way to produce this isomer is irradiation of natTa or natW samples with high energy protons. Irradiation of natTa or natW samples performed for other purposes provides an opportunity to study the corresponding reactions. This paper presents the 178m2Hf independent production cross sections for both targets measured by the gamma-ray spectrometry method. The reaction excitation functions have been obtained for the proton energies from 40 up to 2600 MeV. The experimental results were compared with calculations by various versions of the intranuclear cascade model in the well-known codes: ISABEL, Bertini, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The isomer ratio for the natTa(p,x) 178m2Hf reaction is evaluated on the basis of the available data.

  18. Preparation, characterization, magnetic susceptibility (Eu, Gd and Sm) and XPS studies of Ln{sub 2}ZrTiO{sub 7} (Ln=La, Eu, Dy and Gd)

    SciTech Connect (OSTI)

    Vijaya Kumar, B.; Velchuri, Radha; Rama Devi, V.; Sreedhar, B.; Prasad, G.; Jaya Prakash, D.; Kanagaraj, M.; Arumugam, S.; Vithal, M.

    2011-02-15

    Bulk and nanosized pyrochlore materials Ln{sub 2}ZrTiO{sub 7} (Ln=La, Eu, Dy, Gd and Sm) have been prepared by the sol-gel method. All the samples were characterized by powder X-ray diffraction, Raman and X-ray photoelectron spectroscopy. Magnetic susceptibility ({chi}) measurements of Gd{sub 2}ZrTiO{sub 7}, Sm{sub 2}ZrTiO{sub 7} and Eu{sub 2}ZrTiO{sub 7} were carried out by vibrating sample magnetometer in the temperature range 2-320 K. The variation of {chi}{sup -1} (or {chi}) with temperature of Gd{sub 2}ZrTiO{sub 7}, Sm{sub 2}ZrTiO{sub 7} and Eu{sub 2}ZrTiO{sub 7} follows the Curie law, intermediate formula and the Curie-Weiss law, respectively. From the linear portion of {chi}T vs. T{sup -1} plot of Eu{sub 2}ZrTiO{sub 7} from 2 to 15 K, the classical nearest neighbor exchange (J{sup cl}) and dipolar interactions (D{sub nn}) are obtained. The XPS of Ln{sub 2}ZrTiO{sub 7} (Ln=La, Eu, Dy and Gd) gave characteristic peaks for Ln, Ti, Zr and O. The satellite peaks are observed only for 3d La of La{sub 2}ZrTiO{sub 7}. -- Graphical abstract: Sm{sub 2}ZrTiO{sub 7} does not follow the Curie or the Curie-Weiss law. The effective magnetic moment is found to be 0.768 BM (at 300 K), which is smaller than the free ion moment 1.3-1.4 BM. Display Omitted Research Highlights: {yields} Bulk and nano Ln{sub 2}ZrTiO{sub 7} (Ln=La, Eu, Dy, Gd and Sm) have been prepared by the sol-gel method. {yields} The broad Raman lines are attributed to cation disorder and small crystallite size. {yields} XPS of Ln{sub 2}ZrTiO{sub 7} exhibit characteristic X-ray photoelectron spectral features. {yields} Magnetic moment of Gd{sub 2}ZrTiO{sub 7} is obtained from magnetic susceptibility and ESR spectra.

  19. Synthesis, Crystal Structure, and Properties of the Rhomboheral Modification of the Thiospinel CuZr1.86(1)S4

    SciTech Connect (OSTI)

    Dong, Yongkwan; McGuire, Michael A; Hoseop, Yun; DiSalvo, Francis J.

    2009-01-01

    The rhombohedral modification of the thiospinel, CuZr{sub 1.86(1)}S{sub 4}, has been synthesized by the reaction of the constituent elements in an alkali metal halide flux and structurally characterized by single crystal X-ray diffraction techniques. The title compound crystallizes in the rhombohedral space group D{sub 3d}{sup 5}-R{bar 3}m (166, a=7.3552(2) {angstrom}, c=35.832(2) {angstrom}, V=1678.76(13) {angstrom}{sup 3}, Z=12, and R/wR=0.0239/0.0624). The structure is composed of close packed S layers, with a stacking order of ABCBCABABCACAB along the c axis. The Zr and Cu atoms occupy the octahedral and tetrahedral holes between S layers, respectively. Three different kinds of S-M-S layers exist in the structure: layer I has fully occupied Zr and Cu sites, layer II has fully occupied Zr sites but no Cu, and layer III has partially occupied Zr and fully occupied Cu sites. Transport and optical properties indicate that the title compound is a small band gap (1.26 eV) n-type semiconductor.

  20. Localization of vacancies and mobility of lithium ions in Li{sub 2}ZrO{sub 3} as obtained by {sup 6,7}Li NMR

    SciTech Connect (OSTI)

    Baklanova, Ya. V., E-mail: baklanovay@ihim.uran.ru [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 91 Pervomaiskaya str., 620990 Ekaterinburg (Russian Federation); Arapova, I. Yu.; Buzlukov, A.L.; Gerashenko, A.P.; Verkhovskii, S.V.; Mikhalev, K.N. [Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, 18 Kovalevskaya str., 620990 Ekaterinburg (Russian Federation); Denisova, T.A.; Shein, I.R.; Maksimova, L.G. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 91 Pervomaiskaya str., 620990 Ekaterinburg (Russian Federation)

    2013-12-15

    The {sup 6,7}Li NMR spectra and the {sup 7}Li spinlattice relaxation rate were measured on polycrystalline samples of Li{sub 2}ZrO{sub 3}, synthesized at 1050 K and 1300 K. The {sup 7}Li NMR lines were attributed to corresponding structural positions of lithium Li1 and Li2 by comparing the EFG components with those obtained in the first-principles calculations of the charge density in Li{sub 2}ZrO{sub 3}. For both samples the line width of the central {sup 7}Li transition and the spinlattice relaxation time decrease abruptly at the temperature increasing above ?500 K, whereas the EFG parameters are averaged (??{sub Q}?=42 (5) kHz) owing to thermally activated diffusion of lithium ions. - Graphical abstract: Path of lithium ion hopping in lithium zirconate Li{sub 2}ZrO{sub 3}. - Highlights: Polycrystalline samples Li{sub 2}ZrO{sub 3} with monoclinic crystal structure synthesized at different temperatures were investigated by {sup 6,7}Li NMR spectroscopy. Two {sup 6,7}Li NMR lines were attributed to the specific structural positions Li1 and Li2. The distribution of vacancies was clarified for both lithium sites. The activation energy and pathways of lithium diffusion in Li{sub 2}ZrO{sub 3} were defined.

  1. Hydrothermal synthesis and afterglow luminescence properties of hollow SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} spheres for potential application in drug delivery

    SciTech Connect (OSTI)

    Feng, Pengfei; Zhang, Jiachi Qin, Qingsong; Hu, Rui; Wang, Yuhua

    2014-02-01

    Highlights: We designed a novel afterglow labeling material SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} for the first time. Hollow SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} spheres with afterglow were prepared by hydrothermal method. Hollow SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} is a potential afterglow labeling medium for drug delivery. - Abstract: A novel afterglow labeling material SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} with hollow sphere shape and intense afterglow luminescence is prepared by hydrothermal method at 180 C for the first time. The morphology and the sphere growth process of this material are investigated by scanning electron microscopy in detail. The afterglow measurement shows that this hydrothermal obtained material exhibits obvious red afterglow luminescence (550700 nm) of Sm{sup 3+} which can last for 542 s (0.32 mcd/m{sup 2}). The depth of traps in this hydrothermal obtained material is calculated to be as shallow as 0.58 eV. The results demonstrate that although it is necessary to further improve the afterglow performance of the hydrothermal derived hollow SnO{sub 2}:Sm{sup 3+},Zr{sup 4+} spheres, it still can be regarded as a potential afterglow labeling medium for drug delivery.

  2. Crystal structure, short-range oxygen defects, and water adsorption in La- and Nd-modified ZrO{sub 2}

    SciTech Connect (OSTI)

    Loong, C.K.; Richardson, J.W. Jr.; Iton, L.E.; Ozawa, M.

    1995-02-01

    Doping Rare-earth (RE) elements to ZrO{sub 2} helps stabilize the cubic and tetragonal phases and improves resistance to thermal shock and sintering at high temperatures. Since a RE ion has a lower valency (3{sup +}) than Zr ion (4{sup +}), oxygen vacancies are formed to preserve electroneutrality. We have studied the crystal structure of La{sub 0.1}Zr{sub 0.9}O{sub 1.95} and Nd{sub 0.1}Zr{sub 0.9}O{sub 1.95} by neutron diffraction and examined the associated oxygen defects by a Fourier transform of the filtered residual diffuse scattering. The hydration process was investigated by inelastic neutron-scattering measurements of the hydrogen vibrational density of states of the surface hydroxyl groups and physisorbed water on these fine powders. We compare the O-H stretch vibrations for samples from with only surface hydroxyl groups to multilayer coverage of water molecules. The decreasing energies and increasing widths of the O-H stretch bands with increasing H{sub 2}O coverage indicate the influence of hydrogen bonding on the motion of water molecules. Similar elastic and inelastic experiments were also performed on a high surface-area pure ZrO{sub 2} powder.

  3. As-cast microstructures in U-Pu-Zr alloy fuel pins with 5-8 wt.% minor actinides and 0-1.5 wt% rare-earth elements

    SciTech Connect (OSTI)

    Janney, Dawn E. Kennedy, J. Rory

    2010-11-15

    The Idaho National Laboratory (INL) is investigating U-Pu-Zr alloys with low concentrations of minor actinides (Np and Am) and rare-earth elements (La, Ce, Pr, and Nd) as possible nuclear fuels to be used to transmute minor actinides. Alloys with compositions 60U-20Pu-3Am-2Np-15Zr, 42U-30Pu-5Am-3Np-20Zr, 59U-20Pu-3Am-2Np-1RE-15Zr, 58.5U-20Pu-3Am-2Np-1.5RE-15Zr, 41U-30Pu-5Am-3Np-1RE-20Zr, and 40.5U-30Pu-5Am-3Np-1.5RE-20Zr (where numbers represent weight percents of each element and RE is a rare-earth alloy consisting of 6% La, 16% Pr, 25% Ce, and 53% Nd by weight) were arc-melted and vacuum cast as fuel pins approximately 4 mm in diameter. The as-cast pins were sectioned, polished, and examined by scanning electron microscopy. Each alloy contains high-Zr inclusions surrounded by a high-actinide matrix. Alloys with rare-earth elements also contain inclusions that are high in these elements. Within the matrix, concentrations of U and Zr vary inversely, while concentrations of Np and Pu appear approximately constant. Am occurs in the matrix and with some high-rare-earth inclusions, and occasionally as high-Am inclusions in samples without rare-earth elements. - Research Highlights: {yields}Microstructures consist of high-Zr inclusions surrounded by a high-actinide matrix. {yields}Alloys with rare-earth (RE) elements contain inclusions that are high in REs. {yields}Concentrations of U and Zr vary inversely in the matrix. {yields}Am occurs in the matrix and with high-RE inclusions.

  4. Analysis of wear track and debris of stir cast LM13/Zr composite at elevated temperatures

    SciTech Connect (OSTI)

    Panwar, Ranvir Singh, E-mail: ranvir.panwar@thapar.edu; Pandey, O.P., E-mail: oppandey@thapar.edu

    2013-01-15

    Particulate reinforced aluminum metal matrix composite is in high demand in automobile industry where the operational conditions vary from low to high temperature. In order to understand the wear mode at elevated temperature, this study was planned. For this purpose we developed a metal matrix composite containing aluminum alloy (LM13) as matrix and zircon sand as particulate reinforcement by stir casting process. Different amounts of zircon sand (5, 10, 15 and 20 wt.%) were incorporated in the matrix to study the effect of reinforcement on the wear resistance. Dispersion of zircon sand particles in the matrix was confirmed by using optical microscopy. Sliding wear tests were done to study the durability of the composite with respect to the base alloy. The effects of load and temperature on wear behavior from room temperature to 300 Degree-Sign C were studied to understand the wear mechanism deeply. Surface morphology of the worn surfaces after the wear tests as well as wear debris was observed under scanning electron microscope. Mild to severe wear transition was noticed in tests at high temperature and high load. However, there is interesting change in wear behavior of the composite near the critical temperature of the composite. All the observed behavior has been explained with reference to the observed microstructure of the wear track and debris. - Highlights: Black-Right-Pointing-Pointer Good interfacial bonding between zircon sand particles and Al matrix was observed. Black-Right-Pointing-Pointer The effect of temperature on the wear behavior of LM13/Zr composites was studied. Black-Right-Pointing-Pointer Wear resistance of the composite was improved with addition of zircon sand. Black-Right-Pointing-Pointer Transition temperature from mild to severe wear also improved in composite. Black-Right-Pointing-Pointer SEM analysis of the tracks and debris was done to establish wear mechanism.

  5. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy investigation of Al-related dipole at the HfO{sub 2}/Si interface

    SciTech Connect (OSTI)

    Zhu, L. Q.; Barrett, N.; Jegou, P.

    2009-01-15

    The presence of an ultrathin oxide layer at the high-k/SiO{sub 2} interface may result in an interfacial dipole related to the specific high-k dielectric used for the gate stacks. 1 nm HfO{sub 2}/x nmAl{sub 2}O{sub 3}/SiO{sub 2}/Si stacks with different x values (x=0, 0.4, 0.8, 1.2) have been prepared by atomic layer deposition. Using photoelectron spectroscopy, an Al-related interfacial dipole in the HfO{sub 2}/Al{sub 2}O{sub 3}/SiO{sub 2} gate stack has been identified. X-ray photoelectron spectroscopy analysis shows that the dipole is correlated with the formation of an interfacial Al-silicate. The dipole is located at the Al-silicate interface between Al{sub 2}O{sub 3} and SiO{sub 2}, and its strength increases with the increase in Al{sub 2}O{sub 3} thickness because of Al silicate growth. Such Al-related interfacial dipole should have potential applications in future positive metal-oxide-semiconductor devices.

  6. High quality HfO{sub 2}/p-GaSb(001) metal-oxide-semiconductor capacitors with 0.8?nm equivalent oxide thickness

    SciTech Connect (OSTI)

    Barth, Michael; Datta, Suman; Bruce Rayner, G.; McDonnell, Stephen; Wallace, Robert M.; Bennett, Brian R.; Engel-Herbert, Roman

    2014-12-01

    We investigate in-situ cleaning of GaSb surfaces and its effect on the electrical performance of p-type GaSb metal-oxide-semiconductor capacitor (MOSCAP) using a remote hydrogen plasma. Ultrathin HfO{sub 2} films grown by atomic layer deposition were used as a high permittivity gate dielectric. Compared to conventional ex-situ chemical cleaning methods, the in-situ GaSb surface treatment resulted in a drastic improvement in the impedance characteristics of the MOSCAPs, directly evidencing a much lower interface trap density and enhanced Fermi level movement efficiency. We demonstrate that by using a combination of ex-situ and in-situ surface cleaning steps, aggressively scaled HfO{sub 2}/p-GaSb MOSCAP structures with a low equivalent oxide thickness of 0.8?nm and efficient gate modulation of the surface potential are achieved, allowing to push the Fermi level far away from the valence band edge high up into the band gap of GaSb.

  7. Mechanism for atmosphere dependence of laser damage morphology in HfO{sub 2}/SiO{sub 2} high reflective films

    SciTech Connect (OSTI)

    Pu Yunti; Ma Ping; Chen Songlin; Wang Gang; Pan Feng; Zhu Jiliang; Sun Ping; Zhu Xiaohong; Zhu Jianguo; Xiao Dingquan

    2012-07-15

    We show in this paper single-shot and multi-shot laser-induced damage thresholds (LIDTs) of HfO{sub 2}/SiO{sub 2} high reflective films (the reflectance = 99.9%) are affected by the presence of a water layer absorbed on the surface of the porous films. When the water layer was removed with the process of pumping, the single-shot LIDT measured in vacuum dropped to {approx}48% of that measured in air, while the multi-shot LIDT in vacuum dropped to {approx}47% of its atmospheric value for the high reflective films. Typical damage micrographs of the films in air and in vacuum were obtained, showing distinct damage morphologies. Such atmosphere dependence of the laser damage morphology was found to originate from that formation of a water layer on the surface of porous films could cause an increase of horizontal thermal conductivity and a reduction of vertical thermal conductivity. Moreover, laser-induced periodic ripple damages in air were found in the SiO{sub 2} layer from the micrographs. A model of deformation kinematics was used to illustrate the occurrence of the periodic ripple damage, showing that it could be attributed to a contraction of the HfO{sub 2} layer under irradiation by the 5-ns laser pulses in air.

  8. Dispersion of UO{sub 2}F{sub 2} aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.

    1996-12-30

    The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF{sub 6} is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO{sub 2}F{sub 2}). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO{sub 2}F{sub 2} aerosols throughout the operating floor area following B-line break accident in the cell floor area.

  9. In situ study of the role of substrate temperature during atomic layer deposition of HfO{sub 2} on InP

    SciTech Connect (OSTI)

    Dong, H.; Santosh, K.C.; Qin, X.; Brennan, B.; McDonnell, S.; Kim, J.; Zhernokletov, D.; Hinkle, C. L.; Cho, K.; Wallace, R. M.; Department of Physics, University of Texas at Dallas, Richardson, Texas 75080

    2013-10-21

    The dependence of the “self cleaning” effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO{sub 2} on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO{sub 2} at different temperatures. An (NH{sub 4}){sub 2} S treatment is seen to effectively remove native oxides and passivate the InP surfaces independent of substrate temperature studied (200 °C, 250 °C and 300 °C) before and after the ALD process. Density functional theory modeling provides insight into the mechanism of the changes in the P-oxide chemical states.

  10. Generation of WO{sub 3}-ZrO{sub 2} catalysts from solid solutions of tungsten in zirconia

    SciTech Connect (OSTI)

    Cortes-Jacome, Maria A.; Angeles-Chavez, Carlos; Bokhimi, Xim; Toledo-Antonio, J.A. . E-mail: jtoledo@imp.mx

    2006-08-15

    WO{sub 3}-ZrO{sub 2} samples were obtained by precipitating zirconium oxynitrate in presence of WO{sub 4} {sup =} species in solution from ammonium metatungstate at pH=10.0. Samples were characterized by atomic absorption spectroscopy, thermal analysis, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and energy filtered-TEM. The ammonia retained in the dried sample produced a reductive atmosphere to generate W{sup 5+} ions coexisting with W{sup 6+} ions to produce a solid solution of tungsten in the zirconia lattice to stabilize the zirconia tetragonal phase when the sample was annealed at 560 deg. C. When the sample was annealed at 800 deg. C, the W atoms near crystallite surface were oxidized to W{sup 6+}, producing patches of WO{sub 3} on the zirconia crystallite. The HR-TEM analysis confirmed the existence of the solid solution when the sample was annealed at 560 deg. C, and two types of crystalline regions were identified: One with nearly spherical morphology, an average diameter of 8 nm and the atomic distribution of tetragonal zirconia. The second one had a non-spherical morphology with well-faceted faces and dimensions larger than 30 nm, and the atom distribution of tetragonal zirconia. When samples were annealed at 800 deg. C two different zirconia crystallites were formed: Those where only part of the dissolved tungsten atoms segregated to crystallite surface producing patches of nanocrystalline WO{sub 3} on the crystallite surface of tetragonal zirconia stabilized with tungsten. The second type corresponded to monoclinic zirconia crystallites with patches of nanocrystalline WO{sub 3} on their surface. The tungsten segregation gave rise to the WO{sub 3}-ZrO{sub 2} catalysts. - Graphical abstract: WO {sub x} -ZrO{sub 2} catalysts were obtained by precipitating zirconium oxynitrate in presence of WO{sub 4} {sup =}species. Initially, the W atoms remained inside the crystallite after

  11. Germanium-induced stabilization of a very high-k zirconia phase in ZrO{sub 2}/GeO{sub 2} gate stacks

    SciTech Connect (OSTI)

    Tsipas, P.; Volkos, S. N.; Sotiropoulos, A.; Galata, S. F.; Mavrou, G.; Tsoutsou, D.; Panayiotatos, Y.; Dimoulas, A.; Marchiori, C.; Fompeyrine, J.

    2008-08-25

    Electrical data on ZrO{sub 2}/GeO{sub 2} stacks prepared by atomic oxygen beam deposition on Ge at 225 deg. C reveal a relatively weak dependence of the stack equivalent oxide thickness upon the ZrO{sub 2} thickness. This trend points to a very high zirconia dielectric permittivity (k) value which is estimated to be around 44. This is indicative of zirconia crystallization into a tetragonal phase which is also supported by x-ray diffraction data. X-ray photoelectron spectroscopy analysis is in line with the assumption that due to a finite GeO{sub 2} decomposition, Ge is incorporated into the growing ZrO{sub 2}, thus, stabilizing the high-k tetragonal phase.

  12. Comparative study of local atomic structures in Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) metallic glasses

    SciTech Connect (OSTI)

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Ho, K. M.; Kramer, M. J.

    2015-11-21

    Extensive analysis has been performed to understand the key structural motifs accounting for the difference in glass forming ability in the Zr-Cu and Zr-Ni binary alloy systems. Here, the reliable atomic structure models of Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) are constructed using the combination of X-ray diffraction experiments, ab initio molecular dynamics simulations and a constrained reverse Monte Carlo method. We observe a systematic variation of the interatomic distance of different atomic pairs with respect to the alloy composition. The ideal icosahedral content in all samples is limited, despite the high content of five-fold symmetry motifs. We also demonstrate that the population of Z-clusters in Zr{sub 2}Cu glass is much higher than that in the Zr{sub 2}Ni and Zr{sub 2}Cu{sub 0.5}Ni{sub 0.5} samples. And Z12 〈0, 0, 12, 0〉 Voronoi polyhedra clusters prefer to form around Cu atoms, while Ni-centered clusters are more like Z11 〈0, 2, 8, 1〉 clusters, which is less energetically stable compared to Z12 clusters. These two different structural properties may account for the higher glass forming ability of Zr{sub 2}Cu alloy than that of Zr{sub 2}Ni alloy.

  13. Solid solubilities of (La Nd,){sub 2}(Zr,Ti){sub 2}O{sub 7} phases deduced by neutron diffraction

    SciTech Connect (OSTI)

    Harvey, Elizabeth J.; Whittle, Karl R.; Lumpkin, Gregory R.; Smith, Ronald I.; Redfern, Simon A.T. . E-mail: satr@cam.ac.uk

    2005-03-15

    Time-of-flight powder neutron diffraction has been performed on oxides with composition (La{sub 1-x}Nd{sub x}){sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}(Zr{sub 1-x}Ti{sub x}){sub 2}O{sub 7}, where x=0, 0.2, 0.4,...1.0, in order to determine the solid solution behaviour across each series. Between La{sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}Zr{sub 2}O{sub 7}, a cubic pyrochlore phase is observed (Fd3-bar m, Z=8). A linear decrease in the lattice parameter from 10.8047 to 10.6758A indicates complete miscibility of the two end-members. For the same series, the 48f oxygen x-parameter increases from 0.3313 to 0.3348, suggesting increased distortion of the 6 coordinate B sites and reduced distortion of the 8 coordinate A sites. There is limited solubility of Nd{sub 2}Ti{sub 2}O{sub 7} in Nd{sub 2}Zr{sub 2}O{sub 7}. Exsolution of a monoclinic phase (P2{sub 1}, Z=8) rich in Nd{sub 2}Ti{sub 2}O{sub 7} is observed at approximately x=0.56. The compositional range over which a solid solution exists is more extensive than that which has been previously reported. The solubility of Nd{sub 2}Zr{sub 2}O{sub 7} in Nd{sub 2}Ti{sub 2}O{sub 7} is very low.

  14. Luminescence properties of ZrW{sub 2}O{sub 8}:Eu{sup 3+} nanophosphors for white light emitting diodes

    SciTech Connect (OSTI)

    Liao, Jinsheng Liu, Shaohua; Wen, He-Rui; Nie, Liling; Zhong, Laifu

    2015-10-15

    Highlights: • Eu{sup 3+} ions occupy C{sub 1} point group of the Zr{sup 4+} site in ZrW{sub 2}O{sub 8} crystals. • The optimum doping concentration of Eu{sup 3+} was determined for the red emission. • ZrW{sub 2}O{sub 8}:Eu possess high quantum efficiency and suitable chromaticity coordinates. - Abstract: ZrW{sub 2}O{sub 8}:Eu{sup 3+} nanophosphors (ca. 60 nm) with different Eu{sup 3+} doping concentrations were obtained using hydrothermal syntheses. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence excitation and emission spectra as well as decay curve measurements were used for the characterization. Under 466 nm excitation, strong red emission at 616 nm corresponding to {sup 5}D{sub 0}–{sup 7}F{sub 2} transition of Eu{sup 3+} was observed for ZrW{sub 2}O{sub 8}:Eu{sup 3+} (9 mol%) phosphors. The values of intensity parameter Ω{sub 2} and Ω{sub 4} are 17.82 × 10{sup −20} cm{sup 2} and 1.092 × 10{sup −20} cm{sup 2}, respectively. The high quantum efficiency of 83.5% of the ZrW{sub 2}O{sub 8}:Eu{sup 3+} (9 mol%) suggests this material could be promising red phosphor for generating white light in phosphor-converted white light-emitting diodes (LED)

  15. Temperature-dependent local structural properties of redox Pt nanoparticles on TiO2 and ZrO2 supports

    SciTech Connect (OSTI)

    Jeong, Eun -Suk; Park, Chang -In; Jin, Zhenlan; Hwang, In -Hui; Son, Jae -Kwan; Kim, Mi -Young; Choi, Jae -Soon; Han, Sang -Wook

    2015-01-21

    This paper examined the local structural properties of Pt nanoparticles on SiO2, TiO2–SiO2, and ZrO2–SiO2 supports to better understand the impact of oxide-support type on the performance of Pt-based catalysts. In situ X-ray absorption fine structure (XAFS) measurements were taken for the Pt L3-edge in a temperature range from 300 to 700 K in He, H2, and O2 gas environments. The XAFS measurements demonstrated that Pt atoms were highly dispersed on TiO2–SiO2 and ZrO2–SiO2 forming pancake-shaped nanoparticles, whereas Pt atoms formed larger particles of hemispherical shapes on SiO2 supports. Contrary to the SiO2 case, the coordination numbers for Pt, Ti, and Zr around Pt atoms on the TiO2–SiO2 and ZrO2–SiO2 supports were nearly constant from 300 to 700 K under the different gas environments. These results are consistent with the improvements in thermal stability of Pt nanoparticles achieved by incorporating TiO2 or ZrO2 on the surface of SiO2 supports. XAFS analysis further indicated that the enhanced dispersion and stability of Pt were a consequence of the strong metal support interaction via Pt–Ti and Pt–Zr bonds.

  16. Temperature-dependent local structural properties of redox Pt nanoparticles on TiO2 and ZrO2 supports

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jeong, Eun -Suk; Park, Chang -In; Jin, Zhenlan; Hwang, In -Hui; Son, Jae -Kwan; Kim, Mi -Young; Choi, Jae -Soon; Han, Sang -Wook

    2015-01-21

    This paper examined the local structural properties of Pt nanoparticles on SiO2, TiO2–SiO2, and ZrO2–SiO2 supports to better understand the impact of oxide-support type on the performance of Pt-based catalysts. In situ X-ray absorption fine structure (XAFS) measurements were taken for the Pt L3-edge in a temperature range from 300 to 700 K in He, H2, and O2 gas environments. The XAFS measurements demonstrated that Pt atoms were highly dispersed on TiO2–SiO2 and ZrO2–SiO2 forming pancake-shaped nanoparticles, whereas Pt atoms formed larger particles of hemispherical shapes on SiO2 supports. Contrary to the SiO2 case, the coordination numbers for Pt, Ti,more » and Zr around Pt atoms on the TiO2–SiO2 and ZrO2–SiO2 supports were nearly constant from 300 to 700 K under the different gas environments. These results are consistent with the improvements in thermal stability of Pt nanoparticles achieved by incorporating TiO2 or ZrO2 on the surface of SiO2 supports. XAFS analysis further indicated that the enhanced dispersion and stability of Pt were a consequence of the strong metal support interaction via Pt–Ti and Pt–Zr bonds.« less

  17. Ir-based alloys for ultra-high temperature applications

    DOE Patents [OSTI]

    Liu, Chain T.; George, Easo P.; Bloom, Everett E.

    2006-01-03

    An alloy composition includes, in atomic percent: about 1 to about 10% of at least one element selected from the group consisting of Zr and Hf, balance Ir.

  18. High temperature refractory of MgCr.sub.2 O.sub.4 matrix and unstabilized ZrO.sub.2 particles

    DOE Patents [OSTI]

    Singh, Jitendra P.; James, Jawana J.; Picciolo, John J.

    1987-01-01

    A high chromia refractory composite has been developed with improved thermal shock resistance and containing about 5-30 wt. % of unstabilized ZrO.sub.2 having a temperature-dependent phase change resulting in large expansion mismatch between the ZrO.sub.2 and the chromia matrix which causes microcracks to form during cooling in the high chromia matrix. The particle size preferably is primarily between about 0.6-5 microns and particularly below about 3 microns with an average size in the order of 1.2-1.8 microns.

  19. Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe{sub 2} compounds

    SciTech Connect (OSTI)

    Diop, L. V. B. Isnard, O.; Kastil, J.; Arnold, Z.; Kamarad, J.

    2014-10-28

    The magnetism and transport properties were studied for Laves (Hf,Ta)Fe{sub 2} itinerant-electron compounds, which exhibit a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state upon heating. At finite temperatures, the field-induced metamagnetic phase transition between the AFM and FM has considerable effects on the transport properties of these model metamagnetic compounds. A large negative magnetoresistance of about 14% is observed in accordance with the metamagnetic transition. The magnetic phase diagram is determined for the Laves Hf{sub 1?x}Ta{sub x}Fe{sub 2} series and its Ta concentration dependence discussed. An unusual behavior is revealed in the paramagnetic state of intermediate compositions, it gives rise to the rapid increase and saturation of the local spin fluctuations of the 3d electrons. This new result is analysed in the frame of the theory of Moriya. For a chosen composition Hf{sub 0.825}Ta{sub 0.175}Fe{sub 2}, exhibiting such remarkable features, a detailed investigation is carried out under hydrostatic pressure up to 1?GPa in order to investigate the volume effect on the magnetic properties. With increasing pressure, the magnetic transition temperature T{sub FM-AFM} from ferromagnetic to antiferromagnetic order decreases strongly non-linearly and disappears at a critical pressure of 0.75?GPa. In the pressure-induced AFM state, the field-induced first-order AFM-FM transition appears and the complex temperature dependence of the AFM-FM transition field is explained by the contribution from both the magnetic and elastic energies caused by the significant temperature variation of the amplitude of the local Fe magnetic moment. The application of an external pressure leads also to the progressive decrease of the Nel temperature T{sub N}. In addition, a large pressure effect on the spontaneous magnetization M{sub S} for pressures below 0.45?GPa, dln(M{sub s})/dP?=??6.3??10{sup ?2?}GPa{sup ?1

  20. Magnetoinfrared spectroscopy of Landau levels and Zeeman splitting of three-dimensional massless Dirac Fermions in ZrTe5

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    R. Y. Chen; Gu, G. D.; Chen, Z. G.; Song, X. -Y.; Schneeloch, J. A.; Wang, F.; Wang, N. L.

    2015-10-22

    We present a magnetoinfrared spectroscopy study on a newly identified three-dimensional (3D) Dirac semimetal ZrTe5. We observe clear transitions between Landau levels and their further splitting under a magnetic field. Both the sequence of transitions and their field dependence follow quantitatively the relation expected for 3D massless Dirac fermions. The measurement also reveals an exceptionally low magnetic field needed to drive the compound into its quantum limit, demonstrating that ZrTe5 is an extremely clean system and ideal platform for studying 3D Dirac fermions. The splitting of the Landau levels provides direct, bulk spectroscopic evidence that a relatively weak magnetic fieldmore » can produce a sizable Zeeman effect on the 3D Dirac fermions, which lifts the spin degeneracy of Landau levels. As a result, our analysis indicates that the compound evolves from a Dirac semimetal into a topological line-node semimetal under the current magnetic field configuration.« less

  1. High- and low-Am RE inclusion phases in a U-Np-Pu-Am-Zr alloy

    SciTech Connect (OSTI)

    Janney, Dawn E.; Madden, James W.; O'Holleran, Thomas P.; Kennedy, J. Rory

    2015-03-01

    Structural, microstructural, and microchemical data were collected from rare-earth inclusions in an as-cast U-Pu-Zr alloy with ~3 at% Am, 2% Np, and 9% rare-earth elements (La, Ce, Pr, and Nd). Two RE phases with different concentrations of Am were identified. The composition of high-Am RE inclusions is ~2-5 at% La, 15-20 % Ce, 5-10% Pr, 25-45% Nd, 1% Np, 5-10% Pu, and 10-20% Am. Some areas also have O, although this does not appear to be an essential part of the high-Am RE phase. The inclusions have a face-centered cubic structure with a lattice parameter a ~ 0.54 nm. The composition of the only low-Am RE inclusion studied in detail is ~~35-40 at% O, 40-45 % Nd, 1-2% Zr, 4-5% La, 9-10% Ce, and 6-7% Pr. This inclusion is an oxide with a crystal structure similar to the room-temperature structure of Nd2O3. Microstructural features suggest that oxidation occurred during casting, and that early crystallization of high-temperature oxides led to formation of two distinct RE phases.

  2. Laser shock peening on Zr-based bulk metallic glass and its effect on plasticity: Experiment and modeling

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cao, Yunfeng; Xie, Xie; Antonaglia, James; Winiarski, Bartlomiej; Wang, Gongyao; Shin, Yung C.; Withers, Philip J.; Dahmen, Karin A.; Liaw, Peter K.

    2015-05-20

    The Zr-based bulk metallic glasses (BMGs) are a new family of attractive materials with good glass-forming ability and excellent mechanical properties, such as high strength and excellent wear resistance, which make them candidates for structural and biomedical materials. Although the mechanical behavior of BMGs has been widely investigated, their deformation mechanisms are still poorly understood. In particular, their poor ductility significantly impedes their industrial application. In the present work, we show that the ductility of Zr-based BMGs with nearly zero plasticity is improved by a laser shock peening technique. Moreover, we map the distribution of laser-induced residual stresses via themore » micro-slot cutting method, and then predict them using a three dimensional finite-element method coupled with a confined plasma model. Reasonable agreement is achieved between the experimental and modeling results. The analysis of serrated flow reveals plentiful and useful information of the underlying deformation process. As a result, our work provides an easy and effective way to extend the ductility of intrinsically-brittle BMGs, opening up wider applications of these materials.« less

  3. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi Syarif, Dani Gustaman

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  4. Laser shock peening on Zr-based bulk metallic glass and its effect on plasticity: Experiment and modeling

    SciTech Connect (OSTI)

    Cao, Yunfeng; Xie, Xie; Antonaglia, James; Winiarski, Bartlomiej; Wang, Gongyao; Shin, Yung C.; Withers, Philip J.; Dahmen, Karin A.; Liaw, Peter K.

    2015-05-20

    The Zr-based bulk metallic glasses (BMGs) are a new family of attractive materials with good glass-forming ability and excellent mechanical properties, such as high strength and excellent wear resistance, which make them candidates for structural and biomedical materials. Although the mechanical behavior of BMGs has been widely investigated, their deformation mechanisms are still poorly understood. In particular, their poor ductility significantly impedes their industrial application. In the present work, we show that the ductility of Zr-based BMGs with nearly zero plasticity is improved by a laser shock peening technique. Moreover, we map the distribution of laser-induced residual stresses via the micro-slot cutting method, and then predict them using a three dimensional finite-element method coupled with a confined plasma model. Reasonable agreement is achieved between the experimental and modeling results. The analysis of serrated flow reveals plentiful and useful information of the underlying deformation process. As a result, our work provides an easy and effective way to extend the ductility of intrinsically-brittle BMGs, opening up wider applications of these materials.

  5. Surface and interfacial reaction study of half cycle atomic layer deposited HfO{sub 2} on chemically treated GaSb surfaces

    SciTech Connect (OSTI)

    Zhernokletov, D. M.; Dong, H.; Brennan, B.; Kim, J.; Yakimov, M.; Tokranov, V.; Oktyabrsky, S.; Wallace, R. M.; Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080

    2013-04-01

    An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (XPS) study was conducted in order to investigate the evolution of the HfO{sub 2} dielectric interface with GaSb(100) surfaces after sulfur passivation and HCl etching, designed to remove the native oxides. With the first pulses of tetrakis(dimethylamido)hafnium(IV) and water, a decrease in the concentration of antimony oxide states present on the HCl-etched surface is observed, while antimony sulfur states diminished below the XPS detection limit on sulfur passivated surface. An increase in the amount of gallium oxide/sulfide is seen, suggesting oxygen or sulfur transfers from antimony to gallium during antimony oxides/sulfides decomposition.

  6. In-operando hard X-ray photoelectron spectroscopy study on the impact of current compliance and switching cycles on oxygen and carbon defects in resistive switching Ti/HfO{sub 2}/TiN cells

    SciTech Connect (OSTI)

    Sowinska, Malgorzata Bertaud, Thomas; Walczyk, Damian; Calka, Pauline; Walczyk, Christian; Thiess, Sebastian; Alff, Lambert; Schroeder, Thomas

    2014-05-28

    In this study, direct experimental materials science evidence of the important theoretical prediction for resistive random access memory (RRAM) technologies that a critical amount of oxygen vacancies is needed to establish stable resistive switching in metal-oxide-metal samples is presented. In detail, a novel in-operando hard X-ray photoelectron spectroscopy technique is applied to non-destructively investigates the influence of the current compliance and direct current voltage sweep cycles on the Ti/HfO{sub 2} interface chemistry and physics of resistive switching Ti/HfO{sub 2}/TiN cells. These studies indeed confirm that current compliance is a critical parameter to control the amount of oxygen vacancies in the conducting filaments in the oxide layer during the RRAM cell operation to achieve stable switching. Furthermore, clear carbon segregation towards the Ti/HfO{sub 2} interface under electrical stress is visible. Since carbon impurities impact the oxygen vacancy defect population under resistive switching, this dynamic carbon segregation to the Ti/HfO{sub 2} interface is suspected to negatively influence RRAM device endurance. Therefore, these results indicate that the RRAM materials engineering needs to include all impurities in the dielectric layer in order to achieve reliable device performance.

  7. Comparison of the vacuum-ultraviolet radiation response of HfO{sub 2}/SiO{sub 2}/Si dielectric stacks with SiO{sub 2}/Si

    SciTech Connect (OSTI)

    Upadhyaya, G. S.; Shohet, J. L.

    2007-02-12

    Vacuum ultraviolet (vuv) emitted during plasma processing degrades dielectrics by generating electron-hole pairs. VUV-induced charging of SiO{sub 2}/p-Si and HfO{sub 2}/SiO{sub 2}/p-Si dielectric stacks are compared. For SiO{sub 2}/p-Si, charging is observed for photon energies >15 eV by ionization of dielectric atoms from photoinjected electrons. In HfO{sub 2}/SiO{sub 2}/p-Si, charging is observed for photon >10 eV and is due to ionization by photoinjected electrons and by H{sup +} trapping in the HfO{sub 2}/SiO{sub 2} bulk. Hydrogen appears during annealing at the Si-SiO{sub 2} interface forming Si-H, which, during irradiation, is depassivated by photoinjected electrons. The authors conclude that dielectric charging in thin oxides (<10 nm) occurs more easily in HfO{sub 2}/SiO{sub 2} than in SiO{sub 2}.

  8. Fast-ion conducting Y{sub 2}(Zr{sub y}Ti{sub 1-y}){sub 2}O{sub 7} pyrochlores: Neutron Rietveld analysis of disorder induced by Zr substitution

    SciTech Connect (OSTI)

    Heremans, C.; Wuensch, B.J.; Stalick, J.K.; Prince, E.

    1995-06-01

    The structure of Y{sub 2}(Zr{sub y}Ti{sub 1-y}){sub 2}O{sub 7} solid solutions progressively changes, with increasing y, from an ordered pyrochlore structure A{sub 2}B{sub 2}O{sub 7}{four_gradient}, space group Fd3m, to a deflect-fluorite structure (A,B){sub 4} (O{sub 0.875}{four_gradient}{sub 0.125}){sub 8}, space group Fm3m, at y = 0.90. The anion array consists of three independent sites O(1), O(2), and O(3), occupying positions 48f, 8a and 8b, respectively, of which 8b is unoccupied in a fully ordered pyrochlore. Rietveld powder-profile analysis of data collected with 1.5453-{angstrom} thermal neutrons was used to determine the structural state of four samples with increasing Zr content (y = 0.30, 0.45, 0.60, and 0.90). Refinements that employed only the pyrochlore superstructure intensity data provided weighted profile residuals that ranged 8.06 to 8.67% compared with expected values of 7.13 to 7.87% derived from counting statistics. The onset of disorder at y = 0.30 is marked by filling of the vacant 8b site with oxygen ions displaced from the nearest-neighbor anion shell - i.e., O(1) in 48f. Only for y > 0.45 does O(2) participate in the disorder. Mixing of the occupancy of cation sites A and B begins only with under occupancy of the O(2) site. The eight-coordinated A site, position 16c, is occupied solely by Y for y {le} 0.45 and is predominantly Y at y = 0.60. The substituted Zr{sup 4+} thus replaces Ti{sup 4+} in the six-coordinated B site for most of the solid-solution series. Complete mixing of all three cation species occurs abruptly over the narrow compositional range 0.60 < y {le} 0.90.

  9. Characterization and oxidation states of Cu and Pd in Pd?CuO/ZnO/ZrO[subscript 2] catalysts for hydrogen production by methanol partial oxidation

    SciTech Connect (OSTI)

    Schuyten, S.; Guerrero, S.; Miller, J.T.; Shibatae, T.; Wolf, E.E.

    2009-01-30

    Copper and zinc oxide based catalysts prepared by coprecipitation were promoted with palladium and ZrO{sub 2}, and their activity and selectivity for methanol oxidative reforming was measured and characterized by N{sub 2}O decomposition, X-ray absorption spectroscopy, BET, X-ray photoelectron spectroscopy, X-ray diffraction, and temperature programmed reduction. Addition of ZrO{sub 2} increased copper dispersion and surface area, with little effect on activity, while palladium promotion significantly enhanced activity with little change of the catalytic structure. A catalyst promoted with both ZrO{sub 2} and palladium yielded hydrogen below 150 C. EXAFS results under reaction conditions showed that the oxidation state of copper was influenced by palladium in the catalyst bulk. A palladium promoted catalyst contained 90% Cu{sup 0}, while the copper in an unpromoted catalyst was 100% Cu{sup 1+} at the same temperature. Palladium preferentially forms an unstable alloy with copper instead of zinc during reduction, which persists during reaction regardless of copper oxidation state. A 100-h time on stream activity measurement showed growth in copper crystallites and change in copper oxidation state resulting in decreasing activity and selectivity. A kinetic model of the reaction pathway showed that palladium and ZrO{sub 2} promoters lower the activation energy of methanol combustion and steam reforming reactions.

  10. Preparation and Characterization of Au-ZrO2-SiO2 Nanocomposite Spheres and Their Application in Enrichment and Detection of Organophosphorus Agents

    SciTech Connect (OSTI)

    Yang, Yuqi; Tu, Haiyang; Zhang, Aidong; Du, Dan; Lin, Yuehe

    2012-03-01

    Au-ZrO{sub 2}-SiO{sub 2} nanocomposite spheres were synthesized and used as selective sorbents for the solid-phase extraction (SPE) of orananophosphorous agents. A non-enzymatic electrochemical sensor based on an Au-ZrO{sub 2}-SiO{sub 2} modified electrode was developed for selective detection of orananophosphorous pesticides (OPs). The Au-ZrO{sub 2}-SiO{sub 2} nanocomposite spheres were synthesized by hydrolysis and condensation of zirconia n-butoxide (TBOZ) on the surface of SiO{sub 2} spheres and then introduction of gold nanoparticles on the surface. Transmission electron microscope and X-ray photoelectron spectroscopy were performed to characterize the formation of the nanocomposite sphere. Fast extraction of OP was achieved by Au-ZrO{sub 2}-SiO{sub 2} modified electrode within 5 min via the specific affinity between zirconia and phosphoric group. The assay yields a broad concentration range of paraoxon-ethyl from 1.0 to 500 ng/mL{sup -1} with a detection limit 0.5 ng/mL{sup -1}. This selective and sensitive method holds great promise for the enrichment and detection of OPs.

  11. Strong blue and white photoluminescence emission of BaZrO{sub 3} undoped and lanthanide doped phosphor for light emitting diodes application

    SciTech Connect (OSTI)

    Romero, V.H.; De la Rosa, E.; Salas, P.; Velazquez-Salazar, J.J.

    2012-12-15

    In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for undoped BaZrO{sub 3} observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm{sup 3+} ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb{sup 3+} and Eu{sup 3+} ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides. - Graphical abstract: Strong blue emission from undoped BaZrO{sub 3} phosphor and white light emission by doping with Tb{sup 3+} (green) and Eu{sup 3+} (red) after 266 nm excitation. Highlights: Black-Right-Pointing-Pointer Blue emission from BaZrO{sub 3} phosphor. Black-Right-Pointing-Pointer Blue emission enhanced with Tm{sup 3+}. Black-Right-Pointing-Pointer White light from BaZrO{sup 3+} phosphor.

  12. Comment on Correlation and relativistic effects in U metal and U-Zr alloy: Validation of ab initio approaches

    SciTech Connect (OSTI)

    Sderlind, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Landa, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Turchi, P. E. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-01

    In a recent paper, Xie et al. [Phys. Rev. B 88, 235128 (2013)], report that the density-functional theory (DFT) with the so-called DFT plus Hubbard U (DFT+U) modification improves energetics, volumes, and formation enthalpies over the standard form of DFT for uranium metal and U-Zr alloys. Also, spin-orbit coupling (SOC) was argued to advance the aforementioned properties in these systems. We demonstrate, contrarily, that neither the Hubbard U approach nor SOC is necessary for a correct description of uranium metal and U-Zr alloys. We further illustrate that the combination of DFT+U and SOC in the projector augmented-wave calculations by Xie et al. results in unrealistically large volume expansions, particularly for ?-U, in stark contrast to all previous calculations for elemental uranium. This in turn may also explain why the DFT+U with SOC model predicts negative enthalpy of mixing in the U-Zr alloy system contradicting conventional DFT as well as one of the main features of the experimental U-Zr phase diagram. The assertion by Xie et al. that DFT+U is an improvement over DFT for these systems is illustrated to be incorrect.

  13. From fluorite to pyrochlore: Characterisation of local and average structure of neodymium zirconate, Nd{sub 2}Zr{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Payne, Julia L.; Tucker, Matthew G.; Evans, Ivana Radosavljević

    2013-09-15

    The structural characterisation of Nd{sub 2}Zr{sub 2}O{sub 7} prepared via a precursor route was performed using a combination of local and average structure probes (neutron total scattering, X-ray and neutron diffraction). We present the first total scattering and reverse Monte Carlo (RMC) modelling study of Nd{sub 2}Zr{sub 2}O{sub 7}, which provides compelling evidence for the adoption of a disordered fluorite-type structure by Nd{sub 2}Zr{sub 2}O{sub 7} prepared by a low-temperature precursor route. Annealing the material at high temperatures leads to a transformation to a pyrochlore-type structure; however, Rietveld refinement using powder neutron diffraction data shows that the oxygen sublattice retains a degree of disorder. - Graphical abstract: Display Omitted - Highlights: • The first total scattering and RMC modelling study of Nd{sub 2}Zr{sub 2}O{sub 7}. • Demonstration that the synthetic route influences the crystal structure adopted. • Insight into the importance of total scattering in studies of complex superstructures, especially for nano-sized materials.

  14. Effects of alloying elements on the formation of < c >-component loops in Zr alloy Excel under heavy ion irradiation.

    SciTech Connect (OSTI)

    Idrees, Yasir; Francis, Elisabeth M.; Yao, Zhongwen; Korinek, Andreas; Kirk, Marquis A.; Sattari, Mohammad; Preuss, Michael; Daymond, M. R.

    2015-05-14

    We report here the microstructural changes occurring in the zirconium alloy Excel (Zr-3.5 wt% Sn-0.8Nb-0.8Mo-0.2Fe) during heavy ion irradiation. In situ irradiation experiments were conducted at reactor operating temperatures on two Zr Excel alloy microstructures with different states of alloying elements, with the states achieved by different solution heat treatments. In the first case, the alloying elements were mostly concentrated in the beta (beta) phase, whereas, in the second case, large Zr-3(Mo,Nb,Fe)(4) secondary phase precipitates (SPPs) were grown in the alpha (alpha) phase by long term aging. The heavy ion induced damage and resultant compositional changes were examined using transmission electron microscopy (TEM) in combination with scanning transmission electron microscope (STEM)-energy dispersive x-ray spectroscopy (EDS) mapping. Significant differences were seen in microstructural evolution between the two different microstructures that were irradiated under similar conditions. Nucleation and growth of < c >-component loops and their dependence on the alloying elements are a major focus of the current investigation. It was observed that the < c >-component loops nucleate readily at 100, 300, and 400 degrees C after a threshold incubation dose (TID), which varies with irradiation temperature and the state of alloying elements. It was found that the TID for the formation of < c >-component loops increases with decrease in irradiation temperature. Alloying elements that are present in the form of SPPs increase the TID compared to when they are in the beta phase solid solution. Dose and temperature dependence of loop size and density are presented. Radiation induced redistribution and clustering of alloying elements (Sn, Mo, and Fe) have been observed and related to the formation of < c >-component loops. It has been shown that at the higher temperature tests, irradiation induced dissolution of precipitates occurs whereas irradiation induced

  15. The fluorite-pyrochlore transformation of Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Clements, Richard; Hester, James R.; Kennedy, Brendan J.; Ling, Chris D.; Stampfl, Anton P.J.

    2011-08-15

    Twelve members of the Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7} series, prepared using conventional solid state methods, have been characterised by neutron powder diffraction. Ho{sub 2}Zr{sub 2}O{sub 7} has a defect fluorite structure whereas Nd{sub 2}Zr{sub 2}O{sub 7} is found to adopt the ordered pyrochlore structure with the composition induced fluorite-pyrochlore transformation occurring near y=1. Rietveld analysis on the neutron data for all the compositions reveals an increase in lattice parameter as a function of y across the entire series, with a small discontinuity associated with the transformation. The neutron profile results suggest that domains of pyrochlore-type initially begin to form before crystallising into a separate phase, and therefore that anion and cation ordering processes are distinct. There is a strong correlation between the extent of disorder in the anion sublattice and the x-parameter of 48f oxygen. These results point the way to a better understanding of the stability observed in pyrochlore structures. - Graphical abstract: Neutron diffraction profiles for Nd{sub 2-y}Ho{sub y}Zr{sub 2}O{sub 7} type oxides reveal details of the transformation from the ordered pyrochlore structure (y=0) to the disordered fluorite structure (y=2). Highlights: > Structures of twelve members of the Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7} series studied using neutron powder diffraction. > Domains of pyrochlore-type materials form at low doping levels. > Higher doping stabilises the pyrochlore. > Anion and cation ordering processes are distinct.

  16. Alternation of the Pd Lattice in Nano-Sized-Pd/ZrO2 Composite during Hydrogen Absorption

    SciTech Connect (OSTI)

    Arachi, Yoshinori; Asai, Takeshi; Emura, Shuichi; Omura, Akira; Nunogaki, Masanobu; Yamaura, Shunichi; Inoue, Akihisa; Arata, Yoshiaki

    2007-02-02

    Structural analysis of high Deuterium absorbed 5 nm Pd particles in dispersed ZrO2 has been carried out using XAFS techniques. X-ray absorption spectra around the Pd K-absorption edge were observed and analyzed. The Pd-Pd bonding distance in the fcc Pd lattice was enlarged by 0.08 {approx} 0.09 A during absorption of deuterium, and it completely reverted to its original state with the release of deuterium while maintaining the crystal lattice symmetry. These changes provide evidence that deuterium locates not on the surface of the Pd particle, but rather within the Pd crystal lattice. XANES spectra clearly indicate that any change in the oxidation state of Pd are not observed, resulting in no reaction of the absorbed Deuterium atoms with Pd atoms. This paper reports the alternation of Pd lattice in nano-sized composite during hydrogen absorption. The possible models of deuterium position in the Pd lattice are also discussed.

  17. Effect of delivery condition on desorption rate of ZrCo metal hydride bed for fusion fuel cycle

    SciTech Connect (OSTI)

    Kang, H.G.; Yun, S.H.; Chung, D.; Oh, Y.H.; Chang, M.H.; Cho, S.; Chung, H.; Song, K.M.

    2015-03-15

    For the safety of fusion fuel cycle, hydrogen isotope gases including tritium are stored as metal hydride form. To satisfy fueling requirement of fusion machine, rapid delivery from metal hydride bed is one of major factors for the development of tritium storage and delivery system. Desorption from metal hydride depends on the operation scenario by pressure and temperature control of the bed. The effect of operation scenario and pump performance on desorption rate of metal hydride bed was experimentally investigated using ZrCo bed. The results showed that the condition of pre-heating scenario before actual delivery of gas affected the delivery performance. Different pumps were connected to desorption line from bed and the effect of pump capacity on desorption rate were also found to be significant. (authors)

  18. Negligible substrate clamping effect on piezoelectric response in (111)-epitaxial tetragonal Pb(Zr, Ti)O{sub 3} films

    SciTech Connect (OSTI)

    Yamada, Tomoaki; Yasumoto, Jun; Ito, Daisuke; Yoshino, Masahito; Nagasaki, Takanori; Sakata, Osami; Imai, Yasuhiko; Kiguchi, Takanori; Shiraishi, Takahisa; Shimizu, Takao; Funakubo, Hiroshi

    2015-08-21

    The converse piezoelectric responses of (111)- and (001)-epitaxial tetragonal Pb(Zr{sub 0.35}Ti{sub 0.65})O{sub 3} [PZT] films were compared to investigate the orientation dependence of the substrate clamping effect. Synchrotron X-ray diffraction (XRD) and piezoelectric force microscopy revealed that the as-grown (111)-PZT film has a polydomain structure with normal twin boundaries that are changed by the poling process to inclined boundaries, as predicted by Romanov et al. [Phys. Status Solidi A 172, 225 (1999)]. Time-resolved synchrotron XRD under bias voltage showed the negligible impact of substrate clamping on the piezoelectric response in the (111)-PZT film, unlike the case for (001)-PZT film. The origin of the negligible clamping effect in the (111)-PZT film is discussed from the viewpoint of the elastic properties and the compensation of lattice distortion between neighboring domains.

  19. Crystal structure and short-range oxygen defects in La- and Nd-modified ZrO{sub 2}

    SciTech Connect (OSTI)

    Loong, C.K.; Richardson, J.W. Jr.; Ozawa, M.; Kimura, M.

    1993-09-01

    The crystal structure of rare-earth modified zirconia and the associated oxygen defects were studied by neutron diffraction. A Rietveld analysis of the neutron powder patterns of heat treated samples of La- and Nd- 10mol%-ZrO{sub 2} revealed the composition of a major tetragonal phase (space group P4{sub 2}/nmc) and a minor cubic phase (space group Fm3m). The sort-range oxygen defects structure was examined by a Fourier-filtering technique. A real-space correlation function, obtained from a Fourier transform of the filtered residual diffuse scattering, showed evidence of static, oxygen-vacancy induced atomic displacements along the <111> and other directions of the pseudocubic cell.

  20. Speciation of uranium in La{sub 2}Zr{sub 2}O{sub 7} pyrochlore by TRPLS

    SciTech Connect (OSTI)

    Mohapatra, M.; Rajeswari, B.; Hon, N. S.; Kadam, R. M. Natarajan, V.

    2015-06-24

    We discuss the speciation of uranium in lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7} =LZO) pyrochlore ceramic prepared via a gel-combustion route. Uranium concentration in the pyrochlore was optimized to 2 mol%. XRD and SEM experiments were carried out to assess the phase and homogeneity of the prepared samples. Time resolved photoluminescence (TRPLS) investigations were carried out for understanding the species stabilized in the pyrochlore host. It was observed that, uranium exists as uranate ion (UO{sub 6}{sup 6−}) in the zirconate host where it replaces the ‘Zr’ ions at its regular site with surrounding defect centers created for charge compensation.

  1. Synthesis and characterization of spherical ZrO{sub 2}:Eu{sup 3+} phosphors by spray pyrolysis process

    SciTech Connect (OSTI)

    Quan, Z.W.; Wang, L.S.; Lin, J. . E-mail: jlin@ns.ciac.jl.cn

    2005-05-18

    Europium doped zirconia (ZrO{sub 2}:Eu{sup 3+}) powder phosphors consisting of spherical, dense and submicrometer size particles were successfully synthesized by a spray drying process followed by a post annealing treatment process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscope (SEM), photoluminescence (PL) spectra as well as lifetimes were utilized to characterize the prepared samples. The results of XRD indicated that the samples began to crystallize at 500 deg. C, and the crystallinity increased with increasing the annealing temperature. The powders with metastable tetragonal symmetry were obtained at relatively low temperature. The effects of annealing temperature, the Eu{sup 3+} concentration as well as the morphology on the PL intensity were investigated in this work.

  2. Pressure induced phase transformations in NaZr{sub 2}(PO{sub 4}){sub 3} studied by X-ray diffraction and Raman spectroscopy

    SciTech Connect (OSTI)

    Kamali, K.; Ravindran, T.R.; Chandra Shekar, N.V.; Pandey, K.K.; Sharma, S.M.

    2015-01-15

    Raman spectroscopic and x-ray diffraction measurements on NaZr{sub 2}(PO{sub 4}){sub 3} were carried out up to 30 GPa at close intervals of pressure, revealing two structural phase transformations around 5 and 6.6 GPa. The second phase at 5.4 GPa is indexed to R3 space group similar to that of RbTi{sub 2}(PO{sub 4}){sub 3}. Bulk modulus decreases abruptly from 53 GPa (B′=4) to 36 GPa (B′=4) in the second phase above 5 GPa. The structure of the phase III at 8.2 GPa is indexed as orthorhombic similar to the case of high temperature phase of monoclinic LiZr{sub 2}(PO{sub 4}){sub 3}. Bulk modulus of this phase III is found to be 65 GPa (B′=4), which is higher than that of the ambient phase. In high pressure Raman studies, modes corresponding to 72 and 112 cm{sup −1} soften in the ambient phase whereas around 5 GPa, the ones at 60, 105, 125 and 190 cm{sup −1} soften with pressure contributing negatively to overall thermal expansion. - Graphical abstract: High pressure study of NaZr{sub 2}(PO{sub 4}){sub 3} shows a reversible phase transition from R-3c to R3 structure at 5 GPa accompanied by an increase in compressibility signaling a polyhedral tilt transition. - Highlights: • NaZr{sub 2}(PO{sub 4}){sub 3} undergoes two reversible phase transitions at 5 and 6.7 GPa. • The transition at 5 is from rhombohedral R-3c to R3 structure. • Bulk modulus of NaZr{sub 2}(PO{sub 4}){sub 3} is lower than that for the isostructural RbTi{sub 2}(PO{sub 4}){sub 3.} • Compressibility increases with substitution of a smaller cation (Na). • Zr-translational and PO{sub 4} librational modes contribute to phase transition.

  3. Crystal structure and antiferromagnetic ordering of quasi-2D [Cu(HF{sub 2})(pyz){sub 2}]TaF{sub 6} (pyz = pyrazine).

    SciTech Connect (OSTI)

    Manson, J. L.; Schlueter, J. A.; McDonald, R. D.; Singleton, J.; Materials Science Division; Eastern Washington Univ.; LANL

    2010-04-01

    The crystal structure of the title compound was determined by X-ray diffraction at 90 and 295 K. Copper(II) ions are coordinated to four bridging pyz ligands to form square layers in the ab-plane. Bridging HF{sub 2}{sup -} ligands join the layers together along the c-axis to afford a tetragonal, three-dimensional (3D) framework that contains Taf{sub 6}{sup -} anions in every cavity. At 295 K, the pyz rings lie exactly perpendicular to the layers and cooling to 90 K induces a canting of those rings. Magnetically, the compound exhibits 2D antiferromagnetic correlations within the 2D layers with an exchange interaction of -13.1(1) K. Weak interlayer interactions, as mediated by Cu-F-H-F-Cu, leads to long-range magnetic order below 4.2 K. Pulsed-field magnetization data at 0.5 K show a concave curvature with increasing B and reveal a saturation magnetization at 35.4 T.

  4. A repetitively pulsed HF laser with a large discharge gap operating on the F{sub 2}-H{sub 2} mixture

    SciTech Connect (OSTI)

    Aleksandrov, Boris S; Klimuk, Evgenii A; Kutumov, Konstantin A; Troshchinenko, G A; Lacour, Bernard M; Puech, Vincent

    2005-09-30

    An efficient repetitively pulsed (RP) HF laser pumped by a barrier electric discharge with a 10-cm discharge gap is developed. A specific output energy E/V=3 and 23 J L{sup -1} and a technical efficiency {eta} equal to 3.4% and 26%, respectively, were obtained in the single-pulse regime for non-chain and chain processes. An average output power of 43 W (E/V{approx}10 J L{sup -1} and {eta}=11.3%) was obtained in the RP mode of the laser with a pulse repetition rate of 10 Hz for a depleted fluorine-hydrogen mixture (20% F{sub 2}, 5% H{sub 2}). Numerical simulation of laser operation under the conditions corresponding to the RP regime for an active medium length of about 0.5 m showed that a specific output energy of 15 J L{sup -1} and a technical efficiency right up to 20% can be attained in a single pulse. A specific output energy {approx}14 J L{sup -1} attained under such conditions in the single-pulse mode for an active medium length of 0.37 m is found to be in good agreement with the theoretical values. (lasers)

  5. How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO2/SiO2 antireflection and high reflection coatings.

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out ofmore » commission. In light of this circumstance, we explored how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. Finally, the coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45⁰ angle of incidence (AOI), in P-polarization (P-pol).« less

  6. Bio-corrosion and cytotoxicity studies on novel Zr55Co30Ti15 and Cu60Zr20Ti20 metallic glasses

    SciTech Connect (OSTI)

    Vincent, S.; Daiwile, A.; Devi, S. S.; Kramer, M. J.; Besser, M. F.; Murty, B. S.; Bhatt, Jatin

    2014-09-26

    Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr55Co30Ti15 and Cu60Zr20Ti20 metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hanks balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 C). Surface morphology of samples after bio-corrosion experiments was observed by scanning electron microscopy. In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.

  7. 100 MeV swift Si{sup 7+} ion induced thermoluminescence studies of nanocrystalline erbium doped ZrO{sub 2}

    SciTech Connect (OSTI)

    Lokesha, H. S.; Nagabhushana, K. R.; Singh, Fouran

    2015-06-24

    Pure and erbium (1mol%) doped nanocrystalline ZrO{sub 2} is synthesized by combustion technique. Thermoluminescence (TL) properties ZrO{sub 2}pellets annealed at 873 K and irradiated by 100 MeV swift Si{sup 7+} ion for various fluence are recorded. The evolution crystalline structure and crystallite size are done using by XRD data. Two TL glow curves, a well resolved one peak at ∼420 K and an unresolved with peak at ∼598 K are observed. TL intensity increases up to 3×10{sup 12} ions cm{sup −2} beyond which the TL intensity decreases. The glow peak shape method is used to calculate the TL trap parameter and discussed in this paper.

  8. In situ observation of defect annihilation in Kr ion-irradiated bulk Fe/amorphous-Fe 2 Zr nanocomposite alloy

    SciTech Connect (OSTI)

    Yu, K. Y.; Fan, Z.; Chen, Y.; Song, M.; Liu, Y.; Wang, H.; Kirk, M. A.; Li, M.; Zhang, X.

    2014-08-26

    Enhanced irradiation tolerance in crystalline multilayers has received significant attention lately. However, little is known on the irradiation response of crystal/amorphous nanolayers. We report on in situ Kr ion irradiation studies of a bulk Fe96Zr4 nanocomposite alloy. Irradiation resulted in amorphization of Fe2Zr and formed crystal/amorphous nanolayers. α-Fe layers exhibited drastically lower defect density and size than those in large α-Fe grains. In situ video revealed that mobile dislocation loops in α-Fe layers were confined by the crystal/amorphous interfaces and kept migrating to annihilate other defects. This study provides new insights on the design of irradiation-tolerant crystal/amorphous nanocomposites.

  9. Electrical conductivity spectra of Sn doped BaTi{sub 0.95}Zr{sub 0.05}O{sub 3}

    SciTech Connect (OSTI)

    Dalal, Biswajit; Sarkar, Babusona; De, S. K.

    2014-05-28

    The alternating current (ac) conductivity spectra of Sn doped BaTi{sub 0.95}Zr{sub 0.05}O{sub 3} prepared by solid state reaction have been studied in the temperature range of 373–473 K. Mixed valency of Sn atoms and the oxygen vacancy controls electrical transport process. The ac conductivity follows Jonscher type power law as a function of frequency. Derived dc conductivity and hopping frequency follow Arrhenius type temperature dependency and have same activation energy. Almost temperature independent nature of frequency exponent indicates that the electrical conduction in Zr and Sn co-doped BaTiO{sub 3} relaxor is quantum mechanical electron tunneling. The conductivity spectra are perfectly scaled using the scaling parameters as dc conductivity and hopping frequency.

  10. Magnetoinfrared spectroscopy of Landau levels and Zeeman splitting of three-dimensional massless Dirac Fermions in ZrTe5

    SciTech Connect (OSTI)

    R. Y. Chen; Gu, G. D.; Chen, Z. G.; Song, X. -Y.; Schneeloch, J. A.; Wang, F.; Wang, N. L.

    2015-10-22

    We present a magnetoinfrared spectroscopy study on a newly identified three-dimensional (3D) Dirac semimetal ZrTe5. We observe clear transitions between Landau levels and their further splitting under a magnetic field. Both the sequence of transitions and their field dependence follow quantitatively the relation expected for 3D massless Dirac fermions. The measurement also reveals an exceptionally low magnetic field needed to drive the compound into its quantum limit, demonstrating that ZrTe5 is an extremely clean system and ideal platform for studying 3D Dirac fermions. The splitting of the Landau levels provides direct, bulk spectroscopic evidence that a relatively weak magnetic field can produce a sizable Zeeman effect on the 3D Dirac fermions, which lifts the spin degeneracy of Landau levels. As a result, our analysis indicates that the compound evolves from a Dirac semimetal into a topological line-node semimetal under the current magnetic field configuration.

  11. Porosity and biocompatibility study of ceramic implants based on ZrO{sub 2} and Al{sub 2}O{sub 3}

    SciTech Connect (OSTI)

    Litvinova, Larisa E-mail: vshupletsova@mail.ru Shupletsova, Valeria E-mail: vshupletsova@mail.ru Leitsin, Vladimir E-mail: vshupletsova@mail.ru; Vasyliev, Roman E-mail: zoubov77@yahoo.com; Zubov, Dmitry E-mail: zoubov77@yahoo.com; Buyakov, Ales E-mail: kulkov@ms.tsc.ru; Kulkov, Sergey E-mail: kulkov@ms.tsc.ru

    2014-11-14

    The work studies ZrO{sub 2}(Me{sub x}O{sub y})-based porous ceramics produced from the powders consisting of hollow spherical particles. It was shown that the structure is represented by a cellular framework with bimodal porosity consisting of sphere-like large pores and pores that were not filled with the powder particles during the compaction. For such ceramics, the increase of pore volume is accompanied by the increased strain in an elastic area. It was also shown that the porous ZrO{sub 2} ceramics had no acute or chronic cytotoxicity. At the same time, ceramics possess the following osteoconductive properties: adhesion support, spreading, proliferation and osteogenic differentiation of MSCs.

  12. Resolving the grain boundary and lattice impedance of hot-pressed Li7La3Zr2O12 garnet electrolytes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tenhaeff, Wyatt E.; Wang, Yangyang; Sokolov, Alexei P.; Wolfenstine, Jeff; Sakamoto, Jeffrey; Dudney, Nancy J.; Rangasamy, Ezhiyl

    2013-07-24

    Here, the cubic-stabilized garnet solid electrolyte with a nominal composition of Li6.28Al0.24La3Zr2O12 is thoroughly characterized by impedance spectroscopy. By varying the frequency of the applied AC signal over 11 orders of magnitude for characterizations from –100 to +60 °C, the relative contributions of grain and grain boundary conduction are unambiguously resolved.

  13. Influence of crystalline phase and defects in the ZrO{sub 2} nanoparticles synthesized by thermal plasma route on its photocatalytic properties

    SciTech Connect (OSTI)

    Nawale, Ashok B.; Kanhe, Nilesh S.; Bhoraskar, S.V.; Mathe, V.L.; Das, A.K.

    2012-11-15

    Graphical abstract: Thermal plasma synthesized nanophase zirconia showing the blue shift in the band gap of monoclinic phase as found from the photoabsorption spectroscopy was found to be the dominant parameter for the enhancement in its photocatalytic activity. The existence of different defect states and their concentration in as synthesized samples also inferred from the photoabsorption measurements were also found to be responsible for the enhanced photocatalytic activity of the samples. Highlights: ? Phase controlled structural formation of nanophase ZrO{sub 2} by thermal plasma route. ? Enhanced photocatalytic degradation rate of methylene blue dye. ? The blue shift in the band gap of monoclinic phase of nanocrystalline ZrO{sub 2}. ? Existence of different defect states in the as synthesized nano phase ZrO{sub 2}. ? Several competing processes which controls the photocatalytic degradation rate. -- Abstract: The photocatalytic activity of pure ZrO{sub 2} samples, prepared by a thermal plasma route, and characterized by X-ray diffraction technique was tested for the degradation of methylene blue, which is known to be a hazardous dye. Although, all these samples synthesized at different operating pressures of the thermal plasma reactor showed the photocatalytic activity; the sample synthesized at 1.33 bar of operating pressure showed the highest photocatalytic activity. The blue shift in the band gap of monoclinic phase, as observed from the photo-absorption spectroscopy, may be attributed to the enhanced photocatalytic activity. The existence of different defect states and their concentration as, inferred from the photo-absorption measurements were also found to be responsible for the enhanced photocatalytic activity of the as synthesized samples.

  14. DEGRADATION OF SM2ZR2O7 THERMAL BARRIER COATING CAUSED BY CALCIUM-MAGNESIUM-ALUMINUM-SILICON OXIDE (CMAS) DEPOSITION

    SciTech Connect (OSTI)

    Wang, Honglong; Sheng, Zhizhi; Tarwater, Emily; Zhang, Xingxing; Dasgupta, Sudip; Fergus, Jeffrey

    2015-03-16

    Rare earth zirconates are promising materials for use as thermal barrier coatings in gas turbine engines. Among the lanthanide zirconate materials, Sm2Zr2O7 with the pyrochlore structure has lower thermal conductivity and better corrosion resistance against calcium-magnesium-aluminum-silicon oxide (CMAS). In this work, after reaction with CMAS, the pyrochlore structure transforms to the cubic fluorite structure and Ca2Sm8(SiO4)6O2 forms in elongated grain.

  15. Hot-isostatic pressing of U-10Zr by grain boundary diffusion and creep cavitation. Part 2: Theory and data analysis

    SciTech Connect (OSTI)

    McDeavitt, S.M.; Solomon, A.A.

    1997-08-01

    Uranium-10 wt % zirconium (U-10Zr) is a fuel alloy that has been used in the Experimental Breeder Reactor-II (EBR-II). The high burnup that was desired in this fuel system made high demands on the mechanical compatibility between fuel and cladding both during normal operation and during safety-related transients when rapid differential expansion may cause high stresses. In general, this mechanical stress can be reduced by cladding deformation if the cladding is sufficiently ductile at high burnup, and/or by fuel hot-pressing. Fortunately, the fuel is very porous when it contacts the cladding, but this porosity gradually fills with solid fission products (primarily lanthanides) that may limit the fuel`s compressibility. If the porosity remains open, gaseous fission products are released and the porous fuel creeps rather than hot-presses under contact stresses. If the pores are closed by sintering or by solid fission products, the porous fuel will hot-isostatic press (HIP), as represented by the models to be discussed. HIP experiments performed at 700 C on U-10Zr samples with different impurity phase contents (Part 1) are analyzed in terms of several creep cavitation models. The coupled diffusion/creep cavitation model of Chen and Argon shows good quantitative agreement with measured HIP rates for hydride- and metal-derived U-10Zr materials, assuming that pores are uniformly distributed on grain boundaries and are of modal size, and that far-field strain rates are negligible. The analysis predicts, for the first time, an asymmetry between HIP and swelling at identical pressure-induced driving forces due to differences in grain boundary stresses. The differences in compressibility of hydride- and metal-derived U-10Zr can be partially explained by differences in pore size and spacing. The relevance of the experiments to description of in-reactor densification under external pressure or contact stress due to fuel/cladding mechanical interaction is discussed.

  16. Thermodynamic Assessment of Hot Corrosion Mechanisms of Superalloys Hastelloy N and Haynes 242 in Eutectic Mixture of Molten Salts KF and ZrF4

    SciTech Connect (OSTI)

    Michael V. Glazoff

    2012-02-01

    The KF - ZrF4 system was considered for the application as a heat exchange agent in molten salt nuclear reactors (MSRs) beginning with the work carried out at ORNL in early fifties. Based on a combination of excellent properties such as thermal conductivity, viscosity in the molten state, and other thermo-physical and rheological properties, it was selected as one of possible candidates for the nuclear reactor secondary heat exchanger loop.

  17. Effect of current compliance and voltage sweep rate on the resistive switching of HfO{sub 2}/ITO/Invar structure as measured by conductive atomic force microscopy

    SciTech Connect (OSTI)

    Wu, You-Lin Liao, Chun-Wei; Ling, Jing-Jenn

    2014-06-16

    The electrical characterization of HfO{sub 2}/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO{sub 2} surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO{sub 2}/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  18. Structure-activity relationship of Au-ZrO2 catalyst on formation of hydroxyl groups and its influence on CO oxidation

    SciTech Connect (OSTI)

    Karwacki, Christopher J; Ganesh, Panchapakesan; Kent, P. R. C.; Gordon, Wesley O; Peterson, Gregory W; Niu, Jun Jie; Gogotsi, Yury G.

    2013-01-01

    The effect of changes in morphology and surface hydroxyl species upon thermal treatment of zirconia on the oxidation activity of Au/ZrO2 catalyst was studied. We observed using transmission Fourier transform infrared (FTIR) spectroscopy progressive changes in the presence of monodentate (type I), bidentate (type II) and hydrogen bridged species (type III) for each of the thermally treated (85 to 500 C) supports consisting of bare zirconia and Au/ZrO2 catalysts. Furthermore, structural changes in zirconia were accompanied by an increase in crystal size (7 to 58 nm) and contraction of the supports porosity (SSA 532 to 7 m2 g 1) with increasing thermal treatment. Deposition of gold nanoparticles under similar preparation conditions on different thermally treated zirconia resulted in changes in the mean gold cluster size, ranging from 3.7 to 5.6 nm. Changes in the surface hydroxyl species, support structure and size of the gold centers are important parameters responsible for the observed decrease (>90%) in CO conversion activity for the Au/ZrO2 catalysts. Density functional theory calculations provide evidence of increased CO binding to Au nanoclusters in the presence of surface hydroxyls on zirconia, which increases charge transfer at the perimeter of the gold nanocluster on zirconia support. This further helps in reducing a model CO-oxidation reaction barrier in the presence of surface hydroxyls. This work demonstrates the need to understand the structure activity relationship of both the support and active particles for the design of catalytic materials.

  19. Structure-Activity Relationship of Au/ZrO2 Catalyst on Formation of Hydroxyl Groups and Its Influence on CO Oxidation

    SciTech Connect (OSTI)

    Karwacki, Christopher J; Ganesh, Panchapakesan; Gordon, Wesley O; Peterson, Gregory W; Niu, Jun Jie; Gogotsi, Yury G.

    2013-01-01

    The effect of changes in morphology and surface hydroxyl species upon thermal treatment of zirconia on the oxidation activity of Au/ZrO2 catalyst was studied. We observed using transmission fourier transform infrared (FTIR) spectroscopy progressive changes in the presence of monodentate (type I), bidentate (type II) and hydrogen bridged species (type III) for each of the thermally treated (85 to 500 C) supports consisting of bare zirconia and Au/ZrO2 catalysts. Furthermore, structural changes in zirconia were accompanied by an increase in crystal size (7 to 58 nm) and contraction of the supports porosity (SSA 532 to 7 m2/g) with increasing thermal treatment. Deposition of gold nanoparticles under similar preparation conditions on different thermally treated zirconia resulted in changes in the mean gold cluster size, ranging from 3.7 to 5.6 nm. Changes in the surface hydroxyl species, support structure and size of the gold centers are important parameters responsible for the observed decrease (> 90 %) in CO conversion activity for the Au/ZrO2 catalysts. Density functional theory calculations provide evidence of increased CO binding to Au nanoclusters in the presence of surface hydroxyls on zirconia, which increases charge transfer at the perimeter of the gold nanocluster on zirconia support. This further helps in reducing a model CO-oxidation reaction barrier in the presence of surface hydroxyls. This work demonstrates the need to understand the structure-activity relationship of both the support and active particles for the design of catalytic materials.

  20. Comparison of Structural Relaxation Behavior in As-Cast and Pre-Annealed Zr-Based Bulk Metallic Glasses Just below Glass Transition

    SciTech Connect (OSTI)

    Haruyama, Osami; Yoshikawa, Kazuyoshi; Yamazaki, Yoshikatsu; Yokoyama, Yoshihiko; Egami, Takeshi

    2015-04-25

    In this paper, the α-relaxation of pre-annealed Zr55Cu30Ni5Al10 bulk metallic glasses (BMGs) was compared with that of as-cast Zr-based BMGs including Zr55Cu30Ni5Al10. The α-relaxation was investigated by volume relaxation. The relaxation behavior was well described by a stretched exponential relaxation function, Φ (t) ≈ exp [ - (t/τ α )β α ], with the isothermal relaxation time, τα, and the Kohlrausch exponent, βα. The βα exhibited the strong temperature dependence for the pre-annealed BMG, while the weak temperature dependence was visualized for the as-cast BMG similar to the dynamic relaxation. The τα’s were modified by Moynihan and Narayanaswamy-Tool-Moynihan methods that reduce the difference in the thermal history of sample. Finally, as a result, the relaxation kinetics in the glass resembled that of a liquid deduced from the behavior of viscosity in the supercooled liquid.

  1. Comparison of Structural Relaxation Behavior in As-Cast and Pre-Annealed Zr-Based Bulk Metallic Glasses Just below Glass Transition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Haruyama, Osami; Yoshikawa, Kazuyoshi; Yamazaki, Yoshikatsu; Yokoyama, Yoshihiko; Egami, Takeshi

    2015-04-25

    In this paper, the α-relaxation of pre-annealed Zr55Cu30Ni5Al10 bulk metallic glasses (BMGs) was compared with that of as-cast Zr-based BMGs including Zr55Cu30Ni5Al10. The α-relaxation was investigated by volume relaxation. The relaxation behavior was well described by a stretched exponential relaxation function, Φ (t) ≈ exp [ - (t/τ α )β α ], with the isothermal relaxation time, τα, and the Kohlrausch exponent, βα. The βα exhibited the strong temperature dependence for the pre-annealed BMG, while the weak temperature dependence was visualized for the as-cast BMG similar to the dynamic relaxation. The τα’s were modified by Moynihan and Narayanaswamy-Tool-Moynihan methods thatmore » reduce the difference in the thermal history of sample. Finally, as a result, the relaxation kinetics in the glass resembled that of a liquid deduced from the behavior of viscosity in the supercooled liquid.« less

  2. Full-length U-xPu-10Zr (x=0, 8, 19 wt%) Fast Reactor Fuel Test in FFTF

    SciTech Connect (OSTI)

    D. L. Porter; H.C. Tsai

    2012-08-01

    The Integral Fast Reactor-1 (IFR-1) experiment performed in the Fast Flux Test Facility (FFTF) was the only U-Pu-10Zr (Pu-0, 8 and 19 wt%) metallic fast reactor test with commercial-length (91.4 cm active fuel column length) conducted to date. With few remaining test reactors there is little opportunity for performing another test with a long active fuel column. The assembly was irradiated to the goal burnup of 10 at.%. The beginning of life (BOL) peak cladding temperature of the hottest pin was 608?C, cooling to 522?C at end of life (EOL). Selected fuel pins were examined non destructively using neutron radiography, precision axial gamma scanning, and both laser and spiral contact cladding profilometry. Destructive exams included plenum gas pressure, volume, and gas composition determinations on a number of pins followed by optical metallography, electron probe microanalysis (EPMA), and alpha and beta gamma autoradiography on a single U-19Pu-10Zr pin. The post-irradiation examinations (PIEs) showed very few differences compared to the short-pin (34.3 cm fuel column) testing performed on fuels of similar composition in Experimental Breeder Reactor-II (EBR-II). The fuel column grew axially slightly less than observed in the short pins, but with the same pattern of decreasing growth with increasing Pu content. There was a difference in the fuel-cladding chemical interaction (FCCI) in that the maximum cladding penetration by interdiffusion with fuel/fission products did not occur at the top of the fuel column where the cladding temperature is highest, as observed in EBR-II tests. Instead, the more exaggerated fission-rate profile of the FFTF pins resulted in a peak FCCI at ~0.7 X/L axial location along the fuel column. This resulted from a lower production of rare earth fission products higher in the fuel column as well as a much smaller delta-T between fuel center and cladding, and therefore less FCCI, despite the higher cladding temperature. This behavior could

  3. Toward a clinical application of ex situ boron neutron capture therapy for lung tumors at the RA-3 reactor in Argentina

    SciTech Connect (OSTI)

    Farías, R. O.; Trivillin, V. A.; Portu, A. M.; Schwint, A. E.; González, S. J.; Garabalino, M. A.; Monti Hughes, A.; Pozzi, E. C. C.; Thorp, S. I.; Curotto, P.; Miller, M. E.; Santa Cruz, G. A.; Saint Martin, G.; Ferraris, S.; Santa María, J.; Rovati, O.; Lange, F.; Bortolussi, S.; Altieri, S.

    2015-07-15

    Purpose: Many types of lung tumors have a very poor prognosis due to their spread in the whole organ volume. The fact that boron neutron capture therapy (BNCT) would allow for selective targeting of all the nodules regardless of their position, prompted a preclinical feasibility study of ex situ BNCT at the thermal neutron facility of RA-3 reactor in the province of Buenos Aires, Argentina. (L)-4p-dihydroxy-borylphenylalanine fructose complex (BPA-F) biodistribution studies in an adult sheep model and computational dosimetry for a human explanted lung were performed to evaluate the feasibility and the therapeutic potential of ex situ BNCT. Methods: Two kinds of boron biodistribution studies were carried out in the healthy sheep: a set of pharmacokinetic studies without lung excision, and a set that consisted of evaluation of boron concentration in the explanted and perfused lung. In order to assess the feasibility of the clinical application of ex situ BNCT at RA-3, a case of multiple lung metastases was analyzed. A detailed computational representation of the geometry of the lung was built based on a real collapsed human lung. Dosimetric calculations and dose limiting considerations were based on the experimental results from the adult sheep, and on the most suitable information published in the literature. In addition, a workable treatment plan was considered to assess the clinical application in a realistic scenario. Results: Concentration-time profiles for the normal sheep showed that the boron kinetics in blood, lung, and skin would adequately represent the boron behavior and absolute uptake expected in human tissues. Results strongly suggest that the distribution of the boron compound is spatially homogeneous in the lung. A constant lung-to-blood ratio of 1.3 ± 0.1 was observed from 80 min after the end of BPA-F infusion. The fact that this ratio remains constant during time would allow the blood boron concentration to be used as a surrogate and indirect

  4. A340RA.pdf

    National Nuclear Security Administration (NNSA)

  5. A341RA.pdf

    National Nuclear Security Administration (NNSA)

  6. A342RA.pdf

    National Nuclear Security Administration (NNSA)

  7. A354RA.pdf

    National Nuclear Security Administration (NNSA)

  8. A355RA.pdf

    National Nuclear Security Administration (NNSA)

  9. A356RA.pdf

    National Nuclear Security Administration (NNSA)

  10. A357RA.pdf

    National Nuclear Security Administration (NNSA)

  11. Salishan-RA-AMTRTS.pptx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the use cases and requirements that prioritize the R&D activities associated with the ATM RTS. * Augment the community in their efforts to develop sharable AMT RTS components....

  12. RA10(82911).pdf

    National Nuclear Security Administration (NNSA)

  13. RA9(112210).pdf

    National Nuclear Security Administration (NNSA)

  14. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    SciTech Connect (OSTI)

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  15. Casting evaluation of U-Zr alloy system fuel slug for SFR prepared by injection casting method

    SciTech Connect (OSTI)

    Song, Hoon; Kim, Jong-Hwan; Kim, Ki-Hwan; Lee, Chan-Bock

    2013-07-01

    Metal fuel slugs of U-Pu-Zr alloys for Sodium-cooled Fast Reactor (SFR) have conventionally been fabricated by a vacuum injection casting method. Recently, management of minor actinides (MA) became an important issue because direct disposal of the long-lived MA can be a long-term burden for a tentative repository up to several hundreds of thousand years. In order to recycle transuranic elements (TRU) retained in spent nuclear fuel, remote fabrication capability in a shielded hot cell should be prepared. Moreover, generation of long-lived radioactive wastes and loss of volatile species should be minimized during the recycled fuel fabrication step. In order to prevent the evaporation of volatile elements such as Am, alternative fabrication methods of metal fuel slugs have been studied applying gravity casting, and improved injection casting in KAERI, including melting under inert atmosphere. And then, metal fuel slugs were examined with casting soundness, density, chemical analysis, particle size distribution and microstructural characteristics. Based on these results there is a high level of confidence that Am losses will also be effectively controlled by application of a modest amount of overpressure. A surrogate fuel slug was generally soundly cast by improved injection casting method, melted fuel material under inert atmosphere.

  16. A theoretical study of the stability of anionic defects in cubic ZrO2 at extreme conditions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Samanta, Amit

    2016-02-19

    Using first principles density functional theory calculations, we present a study of the structure, mobility, and the thermodynamic stability of anionic defects in the high-temperature cubic phase of ZrO2. Our results suggest that the local structure of an oxygen interstitial depends on the charge state and the cubic symmetry of the anionic sublattice is unstable at 0 K. In addition, the oxygen interstitials and the vacancies exhibit symmetry breaking transitions to low-energy structures with tetragonal distortion of the oxygen sublattice at 0 K. However, the vibrational entropy stabilizes the defect structures with cubic symmetry at 2600–2980 K. The formation freemore » energies of the anionic defects and Gibbs free energy changes associated with different defect reactions are calculated by including the vibrational free energy contributions and the effect of pressure on these defect structures. By analyzing the defect chemistry, we obtain the defect concentrations at finite temperature and pressure conditions using the zero temperature ab initio results as input and find that at low oxygen partial pressures, neutral oxygen vacancies are most dominant and at high oxygen partial pressures, doubly charged anionic defects are dominant. As a result, the relevance of the results to the thermal protective coating capabilities of zirconium-based ceramic composites is elucidated.« less

  17. The influence of surface preparation on low temperature HfO{sub 2} ALD on InGaAs (001) and (110) surfaces

    SciTech Connect (OSTI)

    Kent, Tyler; Edmonds, Mary; Kummel, Andrew C.; Tang, Kechao; Negara, Muhammad Adi; McIntyre, Paul; Chobpattana, Varistha; Mitchell, William; Sahu, Bhagawan; Galatage, Rohit; Droopad, Ravi

    2015-10-28

    Current logic devices rely on 3D architectures, such as the tri-gate field effect transistor (finFET), which utilize the (001) and (110) crystal faces simultaneously thus requiring passivation methods for the (110) face in order to ensure a pristine 3D surface prior to further processing. Scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and correlated electrical measurement on MOSCAPs were utilized to compare the effects of a previously developed in situ pre-atomic layer deposition (ALD) surface clean on the InGaAs (001) and (110) surfaces. Ex situ wet cleans are very effective on the (001) surface but not the (110) surface. Capacitance voltage indicated the (001) surface with no buffered oxide etch had a higher C{sub max} hypothesized to be a result of poor nucleation of HfO{sub 2} on the native oxide. An in situ pre-ALD surface clean employing both atomic H and trimethylaluminum (TMA) pre-pulsing, developed by Chobpattana et al. and Carter et al. for the (001) surface, was demonstrated to be effective on the (110) surface for producing low D{sub it} high C{sub ox} MOSCAPs. Including TMA in the pre-ALD surface clean resulted in reduction of the magnitude of the interface state capacitance. The XPS studies show the role of atomic H pre-pulsing is to remove both carbon and oxygen while STM shows the role of TMA pre-pulsing is to eliminate H induced etching. Devices fabricated at 120 °C and 300 °C were compared.

  18. Atomic layer deposition of crystalline SrHfO{sub 3} directly on Ge (001) for high-k dielectric applications

    SciTech Connect (OSTI)

    McDaniel, Martin D.; Ngo, Thong Q.; Ekerdt, John G.; Hu, Chengqing; Jiang, Aiting; Yu, Edward T.; Lu, Sirong; Smith, David J.; Posadas, Agham; Demkov, Alexander A.

    2015-02-07

    The current work explores the crystalline perovskite oxide, strontium hafnate, as a potential high-k gate dielectric for Ge-based transistors. SrHfO{sub 3} (SHO) is grown directly on Ge by atomic layer deposition and becomes crystalline with epitaxial registry after post-deposition vacuum annealing at ∼700 °C for 5 min. The 2 × 1 reconstructed, clean Ge (001) surface is a necessary template to achieve crystalline films upon annealing. The SHO films exhibit excellent crystallinity, as shown by x-ray diffraction and transmission electron microscopy. The SHO films have favorable electronic properties for consideration as a high-k gate dielectric on Ge, with satisfactory band offsets (>2 eV), low leakage current (<10{sup −5} A/cm{sup 2} at an applied field of 1 MV/cm) at an equivalent oxide thickness of 1 nm, and a reasonable dielectric constant (k ∼ 18). The interface trap density (D{sub it}) is estimated to be as low as ∼2 × 10{sup 12 }cm{sup −2 }eV{sup −1} under the current growth and anneal conditions. Some interfacial reaction is observed between SHO and Ge at temperatures above ∼650 °C, which may contribute to increased D{sub it} value. This study confirms the potential for crystalline oxides grown directly on Ge by atomic layer deposition for advanced electronic applications.

  19. In-situ P/M Al/(ZrB{sub 2} + Al{sub 2}O{sub 3}) MMCs: Processing, microstructure and mechanical characterization[Powder Metallurgy, Metal Matrix Composites

    SciTech Connect (OSTI)

    Feng, C.F.; Froyen, L.

    1999-12-10

    In-situ metal matrix composites (MMCs) offer significant advantages over conventional MMCs from both a technical and an economic standpoint. In this paper, an in-situ MMC, i.e., Al/(10 vol.% Zr2B + 9.2 vol.% Al{sub 2}O{sub 3}), is produced starting from Al + ZrO{sub 2} + B by reactive sintering and subsequently densified by hot-pressing. The formation mechanism of ZrB{sub 2} and Al{sub 2}O{sub 3} in Al matrix is studied by XRD, thermal analysis and microstructural characterization. Reaction kinetics are also investigated based on the results of the reaction mechanism. The properties are evaluated in terms of microstructural characterization, Young's modulus and bending tests. The in-situ processing involves four intermediate steps and the transitional phases are AlB{sub 2}, Zr(O, B){sub 2} and (Zr, Al)(B, O){sub 2}. Regarding the reaction kinetics, conversion fraction vs time relationships have been established for the last three intermediate steps.

  20. X-ray microstructural analysis of nanocrystalline TiZrN thin films by diffraction pattern modeling

    SciTech Connect (OSTI)

    Escobar, D.; Ospina, R.; Gmez, A.G.; Restrepo-Parra, E.; Arango, P.J.

    2014-02-15

    A detailed microstructural characterization of nanocrystalline TiZrN thin films grown at different substrate temperatures (T{sub S}) was carried out by X-ray diffraction (XRD). Total diffraction pattern modeling based on more meaningful microstructural parameters, such as crystallite size distribution and dislocation density, was performed to describe the microstructure of the thin films more precisely. This diffraction modeling has been implemented and used mostly to characterize powders, but the technique can be very useful to study hard thin films by taking certain considerations into account. Nanocrystalline films were grown by using the cathodic pulsed vacuum arc technique on stainless steel 316L substrates, varying the temperature from room temperature to 200 C. Further surface morphology analysis was performed to study the dependence of grain size on substrate temperature using atomic force microscopy (AFM). The crystallite and surface grain sizes obtained and the high density of dislocations observed indicate that the films underwent nanostructured growth. Variations in these microstructural parameters as a function of T{sub S} during deposition revealed a competition between adatom mobility and desorption processes, resulting in a specific microstructure. These films also showed slight anisotropy in their microstructure, and this was incorporated into the diffraction pattern modeling. The resulting model allowed for the films' microstructure during synthesis to be better understood according to the experimental results obtained. - Highlights: Mobility and desorption competition generates a critical temperature. A microstructure anisotropy related to the local strain was observed in thin films. Adatom mobility and desorption influence grain size and microstrain.

  1. Poster — Thur Eve — 64: Preliminary investigation of arc configurations for optimal sparing of normal tissue in hypofractionated stereotactic radiotherapy (HF-SRT) of multiple brain metastases using a 5mm interdigitating micro-multileaf collimator

    SciTech Connect (OSTI)

    Leavens, C; Wronski, M; Lee, YK; Ruschin, M; Soliman, H; Sahgal, A

    2014-08-15

    Purpose: To evaluate normal tissue sparing in intra-cranial HF-SRT, comparing various arc configurations with the Synergy Beam Modulator (SynBM) and Agility linacs, the latter incorporating leaf interdigitation and backup jaws. Methods: Five patients with multiple brain metastases (BMs), (5 BMs (n=2), 3 BMs (n=3)) treated with HF-SRT using 25 Gy (n=2) or 30 Gy (n=3) in 5 fractions, were investigated. Clinical treatment plans used the SynBM. Each patient was retrospectively re-planned on Agility, employing three planning strategies: (A) one isocenter and dedicated arc for each BM; (B) a single isocenter, centrally placed with respect to BMs; (C) the isocenter and arc configuration used in the SynBM plan, where closely spaced (<5cm) BMs used a dedicated isocenter and arcs. Agility plans were normalized for PTV coverage and heterogeneity. Results and Conclusion: Strategy A obtained the greatest improvements over the SynBM plan, where the maximum OAR dose, and mean dose to normal brain (averaged for all patients) were reduced by 55cGy and 25cGy, respectively. Strategy B was limited by having a single isocenter, hence less jaw shielding and increased MLC leakage. The maximum OAR dose was reduced by 13cGy, however mean dose to normal brain increased by 84cGy. Strategy C reduced the maximum OAR dose and mean dose to normal brain by 32cGy and 9cGy, respectively. The results from this study indicate that, for intra-cranial HF-SRT of multiple BMs, Agility plans are equal or better than SynBM plans. Further planning is needed to investigate dose sparing using Strategy A and the SynBM.

  2. Comparative study of structure formation and mechanical behavior of age-hardened Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys

    SciTech Connect (OSTI)

    Inaekyan, K.; Brailovski, V.; Prokoshkin, S.; Pushin, V.; Dubinskiy, S.; Sheremetyev, V.

    2015-05-15

    This work sets out to study the peculiar effects of aging treatment on the structure and mechanical behavior of cold-rolled and annealed biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) (at.%) shape memory alloys by means of transmission electron microscopy, X-ray diffractometry, functional fatigue and thermomechanical testing techniques. Dissimilar effects of aging treatment on the mechanical behavior of Zr- and Ta-doped alloys are explained by the differences in the ω-phase formation rate, precipitate size, fraction and distribution, and by their effect on the alloys' critical stresses and transformation temperatures. Even short-time aging of the TNZ alloy leads to its drastic embrittlement caused by “overaging”. On the contrary, during aging of the TNT alloy, formation of finely dispersed ω-phase precipitates is gradual and controllable, which makes it possible to finely adjust the TNT alloy functional properties using precipitation hardening mechanisms. To create in this alloy nanosubgrained dislocation substructure containing highly-dispersed coherent nanosized ω-phase precipitates, the following optimum thermomechanical treatment is recommended: cold rolling (true strain 0.37), followed by post-deformation annealing (600 °C, 15–30 min) and age-hardening (300 °C, 30 min) thermal treatments. It is shown that in TNT alloy, pre-transition diffraction effects (diffuse reflections) can “mask” the β-phase substructure and morphology of secondary phases. - Highlights: • TNZ alloy is characterized by much higher ω-phase precipitation rate than TNT alloy. • Difference in precipitation rates is linked to the difference in Zr and Ta diffusion mobility. • Aging of nanosubgrained TNZ alloy worsens its properties irrespective of the aging time. • Aging time of nanosubgrained TNT alloy can be optimized to improve its properties.

  3. Investigation of cellular microstructure and enhanced coercivity in sputtered Sm{sub 2}(CoCuFeZr){sub 17} film

    SciTech Connect (OSTI)

    Bhatt, Ranu Schtz, G.; Bhatt, Pramod

    2014-03-14

    We have investigated the effect of annealing temperature on the microstructure and magnetic properties of Sm{sub 2}(CoCuFeZr){sub 17} films prepared using ion beam sputtering at room temperature. The as-deposited film shows randomly oriented polycrystalline grains and exhibits small coercivity (H{sub C}) of 0.04 T at room temperature. Post annealing of these films at 700?C under Ar atmosphere shows significant changes in the microstructure transforming it to the development of cellular growth, concomitant with enhanced coercivity up to 1.3 T. The enhanced coercivity is explained using the domain wall pinning mechanism.

  4. Defect models for sintering and densification of Al/sub 2/O/sub 3/:Ti and Al/sub 2/O/sub 3/:Zr

    SciTech Connect (OSTI)

    Kroger, F.A.

    1984-06-01

    A defect model proposed to explain the effect of titanium doping on the rate of sintering of Al/sub 2/O/sub 3/ is revised to fit the oxidizing conditions of the experiments. The model accounts for the observed change in sintering rate by a change from rate limitation by ions to rate limitation by electrons, but requires the presence of an unusually large concentration of acceptor impurities in the material. Models similar to the ones originally proposed account for the rate of densification of Al/sub 2/O/sub 3/:Zr by hot-pressing in vacuo, provided it is extended by including electronics defects.

  5. Effect of the accumulation of excess Ni atoms in the crystal structure of the intermetallic semiconductor n-ZrNiSn

    SciTech Connect (OSTI)

    Romaka, V. A.; Rogl, P.; Romaka, V. V.; Stadnyk, Yu. V.; Hlil, E. K.; Krajovskii, V. Ya.; Horyn, A. M.

    2013-07-15

    The crystal structure, electron density distribution, and energy, kinetic, and magnetic properties of the n-ZrNiSn intermetallic semiconductor heavily doped with a Ni impurity are investigated. The effect of the accumulation of an excess number of Ni{sub 1+x} atoms in tetrahedral interstices of the crystal structure of the semiconductor is found and the donor nature of such structural defects that change the properties of the semiconductor is established. The results obtained are discussed within the Shklovskii-Efros model of a heavily doped and strongly compensated semiconductor.

  6. Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

    SciTech Connect (OSTI)

    Wang, Jing Zhu, Kongjun; Wu, Xia; Deng, Chaoyong; Peng, Renci; Wang, Jianjun

    2014-08-15

    Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.

  7. Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} single crystals

    SciTech Connect (OSTI)

    Benabdallah, F.; Veber, P. Prakasam, M.; Viraphong, O.; Maglione, M.; Shimamura, K.

    2014-04-14

    Optimal properties like piezoelectricity can be found in polarizable materials for which the structure changes sharply under small composition variations in the vicinity of their morphotropic phase boundary or the triple point in their isobaric temperature-composition phase diagram. In the latter, lead-free (Ba{sub 0.850}Ca{sub 0.150})(Ti{sub 0.900}Zr{sub 0.100})O{sub 3} ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO{sub 2}-ZrO{sub 2} solid solution led to single crystals with various compositions ranging from (Ba{sub 0.857}Ca{sub 0.143})(Ti{sub 0.928}Zr{sub 0.072})O{sub 3} to (Ba{sub 0.953}Ca{sub 0.047})(Ti{sub 0.427}Zr{sub 0.573})O{sub 3}. We evidenced a continuous cross-over from a ferroelectric state at high titanium content to a relaxor one on increasing the zirconium content. Such a property tuning is rather seldom observed in lead-free ferroelectrics and confirms what was already reported for ceramics. Single crystal with (Ba{sub 0.838}Ca{sub 0.162})(Ti{sub 0.854}Zr{sub 0.146})O{sub 3} composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d{sub 31} and k{sub 31} of 93 pC.N{sup −1} and 0.18, respectively, near the room temperature (T = 305 K)

  8. Direct observation of intrinsic piezoelectricity of Pb(Zr,Ti)O{sub 3} by time-resolved x-ray diffraction measurement using single-crystalline films

    SciTech Connect (OSTI)

    Fujisawa, Takashi; Ehara, Yoshitaka; Yasui, Shintaro; Kamo, Takafumi; Funakubo, Hiroshi; Yamada, Tomoaki; Sakata, Osami

    2014-07-07

    Lead zirconate titanate, Pb(Zr,Ti)O{sub 3} or PZT, is one of the most widely investigated ferroelectric and piezoelectric materials due to its superior properties. However, the intrinsic properties of PZT have not been directly measured due to the lack of fabrication of single crystals even though a basic understanding of intrinsic properties has been of interest developing lead-free piezoelectric materials. We demonstrated the direct observation of the intrinsic piezoelectric property by means of the detection of electric-field induced crystal lattice distortion of thick Pb(Zr{sub 0.35}Ti{sub 0.65})O{sub 3} single-crystalline films with single polar-axis orientation and negligible residual strain using the time-resolved X-ray diffraction (XRD) together with the polarization response. Consequently, the effective converse piezoelectric response was experimentally revealed; hence, the electrostrictive coefficient, which is the conversion coefficient between the electrical and mechanical response, was determined. The obtained effective electrostrictive coefficient was 5.2–6.3 × 10{sup −2} m{sup 4}/C{sup 2}, which agrees with theoretical prediction.

  9. Molten Salt Mixture Properties (KF-ZrF4 and KCl-MgCl2) for Use in RELAP5-3D for High Temperature Reactor Application

    SciTech Connect (OSTI)

    N. A. Anderson; P. Sabharwall

    2012-06-01

    Molten salt coolants are being investigated as primary coolants for a fluoride high-temperature reactor and as secondary coolants for high temperature reactors such as the next generation nuclear plant. This work provides a review of the thermophysical properties of candidate molten salt coolants for use as a secondary heat transfer medium from a high temperature reactor to a processing plant. The molten salts LiF-NaF-KF, KF-ZrF4 and KCl-MgCl2 were considered for use in the secondary coolant loop. The thermophysical properties necessary to add the molten salts KF-ZrF4 and KCl-MgCl2 to RELAP5-3D were gathered for potential modeling purposes. The properties of the molten salt LiF-NaF-KF were already available in RELAP5-3D. The effect that the uncertainty in individual properties had on the Nusselt number was evaluated. This uncertainty in the Nusselt number was shown to be nearly independent of the molten salt temperature.

  10. Novel Neo-Pentoxide Precursors for MOCVD Thin Films of TiO(2) and ZrO(2).[1

    SciTech Connect (OSTI)

    Boyle, Timothy J.; Francisco, Laila P.; Gallegos, Jesus J.; Rodriguez, Mark A.; Ward, Timothy L.

    1999-07-14

    Two novel Group IV precursors, titanium (IV) neo-pentoxide, [Ti({mu}-ONep)(ONep){sub 3}]{sub 2} (l), and zirconium (IV) neo-pentoxide, [Zr({mu}-ONep)(ONep){sub 3}]{sub 2} (2), were reported to possess relatively high volatility at low temperatures. These compounds were therefore investigated as MOCVD precursors using a lamp-heated cold-wall CVD reactor and direct sublimation without carrier gas. The ONep derivatives proved to be competitive precursors for the production of thin films of the appropriate MO{sub 2} (M = Ti or Zr) materials in comparison to other metallo-organic precursors. Compound 1 was found to sublime at 120 C with a deposition rate of {approximately}0.350 {mu}m/min onto a substrate at 330 C forming the anatase phase with < 1% residual C found in the final film. Compound 2 was found to sublime at 160 C and deposited as crystalline material at 300 C with < 1% residual C found in the final film. A comparison to standard alkoxide and {beta}-diketonates is presented where appropriate.

  11. Fast crystallization of amorphous Gd{sub 2}Zr{sub 2}O{sub 7} induced by thermally activated electron-beam irradiation

    SciTech Connect (OSTI)

    Huang, Zhangyi; Qi, Jianqi Zhou, Li; Feng, Zhao; Yu, Xiaohe; Gong, Yichao; Yang, Mao; Wei, Nian; Shi, Qiwu; Lu, Tiecheng

    2015-12-07

    We investigate the ionization and displacement effects of an electron-beam (e-beam) on amorphous Gd{sub 2}Zr{sub 2}O{sub 7} synthesized by the co-precipitation and calcination methods. The as-received amorphous specimens were irradiated under electron beams at different energies (80 keV, 120 keV, and 2 MeV) and then characterized by X-ray diffraction and transmission electron microscopy. A metastable fluorite phase was observed in nanocrystalline Gd{sub 2}Zr{sub 2}O{sub 7} and is proposed to arise from the relatively lower surface and interface energy compared with the pyrochlore phase. Fast crystallization could be induced by 120 keV e-beam irradiation (beam current = 0.47 mA/cm{sup 2}). The crystallization occurred on the nanoscale upon ionization irradiation at 400 °C after a dose of less than 10{sup 17} electrons/cm{sup 2}. Under e-beam irradiation, the activation energy for the grain growth process was approximately 10 kJ/mol, but the activation energy was 135 kJ/mol by calcination in a furnace. The thermally activated ionization process was considered the fast crystallization mechanism.

  12. A study of ZnxZryOz mixed oxides for direct conversion of ethanol to isobutene

    SciTech Connect (OSTI)

    Liu, Changjun; Sun, Junming; Smith, Colin; Wang, Yong

    2013-07-15

    ZnxZryOz mixed oxides were studied for direct conversion of ethanol to isobutene. Reaction conditions (temperature, residence time, ethanol molar fraction, steam to carbon ratio), catalyst composition, and pretreatment conditions were investigated, aiming at high-yield production of isobutene under industrially relevant conditions. An isobutene yield of 79% was achieved with an ethanol molar fraction of 8.3% at 475 °C on fresh Zn1Zr8O17 catalysts. Further durability and regeneration tests revealed that the catalyst exhibited very slow deactivation via coking formation with isobutene yield maintained above 75% for more than 10 h time-on-stream. More importantly, the catalysts activity in terms of isobutene yield can be readily recovered after in situ calcination in air at 550 °C for 2.5 h. XRD, TPO, IR analysis of adsorbed pyridine (IR-Py), and nitrogen sorption have been used to characterize the surface physical/chemical properties to correlate the structure and performance of the catalysts.

  13. Microstructure and properties of rapidly solidified beryllium-transition metal alloys. [With small amounts of Ti, Zr and Y (1-3 wt %)

    SciTech Connect (OSTI)

    Jacobson, L.A.; Richardson, S.

    1988-01-01

    Alloys of beryllium with small amounts of Ti, Zr and Y (1-3 wt %) were rapidly solidified using an arc hammer splat technique. Each of these elements forms a dilute eutectic with beryllium, and has very low solid solubility in the alpha phase. In the case of Ti, the Be-rich compound is TiBe/sub 12/, and for Zr and Y, the compound is MBe. The objective of the work was to achieve a fine, uniform dispersion of particles of the intermetallic compound. Since these compounds have very high melting points, it was expected that rapidly solidified microstructures would be relatively stable at elevated temperatures. This microstructural stability should result in improved high temperature properties for the alloys. Microstructures have been characterized using optical, scanning and transmission electron microscopy. Microhardness measurements have been made in order to determine the effects of rapid solidification and to evaluate the effects of high temperature exposure on microstructural stability and property retention. The results will be presented in light of the potential of these alloys for intermediate temperature application. 12 refs., 8 figs.

  14. Transformability of t-ZrO{sub 2} and lattice parameters in plasma sprayed rare-earth oxides stabilized zirconia coatings

    SciTech Connect (OSTI)

    Khor, K.A.; Yang, J.

    1997-11-01

    Coatings of zirconia alloys are mostly used in high-temperature environments as thermal barrier coatings (TBC) to fight hostile working environments and boost energy efficiency. CaO, MgO and Y{sub 2}O{sub 3} are added into zirconia to stabilize the cubic and tetragonal forms and prevent catastrophic cracking as a result of the volume changes on t {r_arrow} m transformation. However, zirconia fully stabilized with either CaO or MgO has been shown to be destabilized on thermal cycling over 1,000 C. Y{sub 2}O{sub 3} stabilized ZrO{sub 2} is stable towards vaporization at high temperature (1,200 C). However, it also encounters the problem of destabilization when it is attacked by the mineral constituents in fuel oil. The destabilization resulted in a detrimental volume change of 3--5%, which can lead to failure, especially if thermal cycling across the transformation temperature takes place. Previous studies on the rare-earth oxide-zirconia system used solid state reaction of mixed powders that are likely to yield chemical inhomogeneities. Recent studies on rapid solidified ZrO{sub 2}-Y{sub 2}O{sub 3} and rare earth oxides stabilized zirconia systems by a hammer and anvil apparatus, which claims to be capable of obtaining compositional homogeneities, suggest the formation of a t{prime} phase that is non-transformable.

  15. In situ X-ray diffraction strain-controlled study of TiNbZr and TiNbTa shape memory alloys: crystal lattice and transformation features

    SciTech Connect (OSTI)

    Dubinskiy, S.; Prokoshkin, S.; Brailovski, V.; Inaekyan, K.; Korotitskiy, A.

    2014-02-15

    Phase and structure transformations in biomedical Ti21.8Nb6.0Zr (TNZ) and Ti19.7Nb5.8Ta (TNT) shape memory alloys (at.%) under and without load in the ? 150 to 100 S temperature range are studied in situ using an original tensile module for a low-temperature chamber of an X-ray diffractometer. Alpha?- and beta-phase lattice parameters, the crystallographic resource of recovery strain, phase and structure transformation sequences, and microstress appearance and disappearance are examined, compared and discussed. For both alloys, the crystallographic resource of recovery strain decreases with temperature increase to become 4.5% for TNZ and 2.5% for TNT alloy (at RT). Loading at low temperatures leads to additional ??-phase formation and reorientation. Heating under load, as compared to strain-free heating, affects the reverse transformation sequence of both alloys in different ways. For TNZ alloy, strain-free heating results in simultaneous ??? and ???? transformations, whereas during heating under stress, they are sequential: ? + ???? precedes ????. For TNT alloy, strain-free heating results in reverse ???? transformation, whereas during heating under stress, ???? transformation is preceded by ??-phase reorientation. - Highlights: Comparative in situ XRD analysis of TiNbZr(Ta) shape memory alloys is realized. Lattice parameters of ?- and ??-phases are calculated in the ? 150 to + 100 C range. The higher the temperature, the lower the ???? transformation strain. Loading at low temperatures results in ??-phase formation and reorientation. Transformation sequences upon heating with and without loading are different.

  16. In situ growth of ZrO{sub 2}–Al{sub 2}O{sub 3} nano-crystalline ceramic coatings via micro arc oxidation of aluminum substrates

    SciTech Connect (OSTI)

    Shoaei-Rad, V.; Bayati, M.R.; Zargar, H.R.; Javadpour, J.; Golestani-Fard, F.; Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran

    2012-06-15

    Highlights: ► ZrO{sub 2}–Al{sub 2}O{sub 3} layers were fabricated by MAO process. ► A formation mechanism was also proposed. ► Effect of voltage and electrolyte composition on layers properties was studied. -- Abstract: Micro arc oxidation technique was employed to grow zirconia–alumina porous layers. Considering XPS, XRD, and EDX results, the layers mainly consisted of α-Al{sub 2}O{sub 3}, γ-Al{sub 2}O{sub 3}, monoclinic ZrO{sub 2}, tetragonal ZrO{sub 2}. Fractions of these phases were observed to change based on the fabrication conditions. Zirconia phases formed not only on the surface, but also in the layers depth. Increasing the voltage as well as utilizing thicker electrolytes resulted in higher zirconium concentration. The average crystalline size of the ZrO{sub 2} and the Al{sub 2}O{sub 3} phases was determined as about 57 and 75 nm. AFM studies revealed that the surface roughness increased with voltage and electrolyte concentration. Morphological evaluations, performed by SEM, showed that the microstructure of the layers strongly depended on the synthesis conditions. The layers revealed a porous structure with a pores size of 40–300 nm. Microcracks were observed to appear when the electrolyte concentration and the applied voltage increased. Finally, a formation mechanism was put forward with emphasis on the chemical and the electrochemical foundations.

  17. Impact of Pt loading methods over mesoporous-assembled TiO{sub 2}ZrO{sub 2} mixed oxide nanocrystal on photocatalytic dye-sensitized H{sub 2} production activity

    SciTech Connect (OSTI)

    Sreethawong, Thammanoon; Yoshikawa, Susumu

    2012-06-15

    Graphical abstract: The Pt loading on the synthesized mesoporous-assembled 0.95TiO{sub 2}0.05ZrO{sub 2} mixed oxide nanocrystal photocatalyst was comparatively investigated by two methods: single-step solgel (SSSG) and photochemical deposition (PCD). The Pt loading by the PCD method was found to be superior to that by the SSSG method in enhancing photocatalytic sensitized hydrogen production under visible light irradiation. The Pt loading amount and PCD conditions, i.e. light irradiation time and light intensity, also had a strong effect on the photocatalytic hydrogen production activity. Highlights: ? Pt-loaded mesoporous-assembled 0.95TiO{sub 2}0.05ZrO{sub 2} nanocrystals were synthesized. ? Pt loading was performed by single-step solgel and photochemical deposition. ? Pt loading by photochemical deposition more enhanced photocatalytic H{sub 2} production. ? Pt loading amount and photochemical deposition conditions were optimized. -- Abstract: In this work, the photocatalytic water splitting under visible light irradiation for hydrogen production was investigated by using Eosin Y-sensitized Pt-loaded mesoporous-assembled TiO{sub 2}ZrO{sub 2} mixed oxide nanocrystal photocatalysts. The mesoporous-assembled TiO{sub 2}ZrO{sub 2} mixed oxide with the TiO{sub 2}-to-ZrO{sub 2} molar ratio of 95:5 (i.e. 0.95TiO{sub 2}0.05ZrO{sub 2}) was synthesized by using a solgel process with the aid of a structure-directing surfactant. The Pt loading was comparatively performed via two different effective methods: single-step solgel (SSSG) and photochemical deposition (PCD). The synthesized photocatalysts were methodically characterized by N{sub 2} adsorptiondesorption, XRD, UVvisible spectroscopy, SEMEDX, TEMEDX, TPR, and H{sub 2} chemisorption analyses. The results revealed that the Pt loading by the PCD method greatly enhanced the photocatalytic hydrogen production activity of the synthesized mesoporous-assembled 0.95TiO{sub 2}0.05ZrO{sub 2} mixed oxide

  18. Order-disorder transition in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} pyrochlore solid solution: An X-ray diffraction and Raman spectroscopic study

    SciTech Connect (OSTI)

    Mandal, B.P.; Banerji, Ankita; Sathe, Vasant; Deb, S.K.; Tyagi, A.K.

    2007-10-15

    Powder X-ray diffraction (XRD) and Raman spectroscopic study of order-disorder-phase transition with increase in the content of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} solid solution is being reported. It has been observed from Rietveld analysis that with increase in concentration of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7}, the value of the x parameter of the 48f oxygen changes from 0.332(1) to 0.343(1) with a sudden change in the slope for y=1.8, which indicates that the structure is transforming from ordered pyrochlore to disordered pyrochlore. In addition to that a sudden and drastic change in the Raman spectra including changes in the position and width of several Raman modes beyond y{>=}1.8 has also been observed which has been correlated with increasing disorder. Based on these studies, it is suggested that there is a discontinuous order-disorder transition from 'perfect pyrochlore' to 'defect pyrochlore' phase in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} solid solution. - Graphical abstract: Raman spectra of Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} with increasing proportion of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} series. A transition from ordered pyrochlore to disordered pyrochlore can be seen at y{approx}1.8.

  19. Enhancement of pyroelectric signal by continuous ultraviolet illumination of epitaxial Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} films

    SciTech Connect (OSTI)

    Pintilie, L.; Iuga, A.; Botea, M.

    2014-09-29

    The pyroelectric signal generated by an epitaxial Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} film can be enhanced by continuous illumination with ultraviolet (UV) light. The measured signal increases more than 2 times at low modulation frequencies of the incident infrared (IR) radiation (∼10 Hz) and at wavelengths where the short-circuit photocurrent presents the maximum value (∼280–300 nm). The tentative explanation is that the changes in polarization induced by the temperature variation under modulated IR illumination are generating a variable internal electric field, able to collect the photogenerated carriers produced under continuous UV illumination leading to an additional signal in phase with the pyroelectric one. This finding could be exploited for designing pyroelectric detectors with enhanced characteristics by combining both UV and IR responses.

  20. Phases in ceria-zirconia binary oxide (1-x)CeO2-xZrO2 nanoparticles: the size effects

    SciTech Connect (OSTI)

    Zhang,F.; Chen, C.; Hanson, J.; Herman, I.; Chan, S.

    2006-01-01

    The phases of ceria-zirconia nanoparticles observed in air are studied as a function of particle size and composition by X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The emergence of two tetragonal phases t{prime}{prime} and t monotonically moves toward higher zirconia concentrations with decreasing particle size. A smaller particle size increases the solubility of zirconia in cubic ceria, while higher zirconia content in ceria stabilizes against coarsening. In particular, the cubic Ce{sub 1-x}Zr{sub x}O{sub 2-y} is persistent and is 8% in phase amount even at 90% zirconia with 33 nm crystal size. Neither the monoclinic phase m nor the tetragonal phase t{prime} is observed in the present nanoparticles (<40 nm). The effectiveness of these nanoparticles as oxygen source-and-sink in catalytic support is largely due to the persistence of the cubic and the t{prime}{prime} phases.