National Library of Energy BETA

Sample records for db cr mo

  1. Microsoft Word - chapter FeCrMo_ver2.doc

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

    Low-Alloy Ferritic Steels Fe-Cr-Mo Tempered December 8, 2005 ... strength level, material processing, and heat treatment 1. ... yield strength, hydrogen gas pressure, and temperature. ...

  2. 9 Cr-- 1 Mo steel material for high temperature application

    DOE Patents [OSTI]

    Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-11-27

    One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

  3. Characterization of modified 9 Cr-1 Mo steel extruded pipe

    SciTech Connect (OSTI)

    Sikka, V.K.; Hart, M.D.

    1985-04-01

    The fabrication of hot-extruded pipe of modified 9 Cr-1 Mo steel at Cameron Iron Works is described. The report also deals with the tempering response; tensile, Charpy impact, and creep properties; and microstructure of the hot-extruded pipe. The tensile properties of the pipe are compared with the average and average -1.65 standard error of estimate curves for various product forms of several commercial heats of this alloy. The creep-rupture properties are compared with the average curve for various product forms of the commercial heats.

  4. Microsoft Word - chapter FeNiCrMo_ver4.doc

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

    Low-Alloy Ferritic Steels Fe-Ni-Cr-Mo Tempered December 8, ... strength level, material processing, and heat treatment 1. ... steel composition, hydrogen gas pressure, and temperature. ...

  5. Electrochemical Testing of Ni-Cr-Mo-Gd Alloys

    SciTech Connect (OSTI)

    T. E. Lister; R. E. Mizia; H. Tian

    2005-10-01

    The waste package site recommendation design specified a boron-containing stainless steel, Neutronit 976/978, for fabrication of the internal baskets that will be used as a corrosion-resistant neutron-absorbing material. Recent corrosion test results gave higher-than-expected corrosion rates for this material. The material callout for these components has been changed to a Ni-Cr-Mo-Gd alloy (ASTM-B 932-04, UNS N06464) that is being developed at the Idaho National Laboratory. This report discusses the results of initial corrosion testing of this material in simulated in-package environments that could contact the fuel baskets after breach of the waste package outer barrier. The corrosion test matrix was executed using the potentiodynamic and potentiostatic electrochemical test techniques. The alloy performance shows low rates of general corrosion after initial removal of a gadolinium-rich second phase that intersects the surface. The high halide-containing test solutions exhibited greater tendencies toward initiation of crevice corrosion.

  6. A pseudo binary y-Gd solidification diagram for Ni-Cr-Mo-Gd alloys...

    Office of Scientific and Technical Information (OSTI)

    Title: A pseudo binary y-Gd solidification diagram for Ni-Cr-Mo-Gd alloys. No abstract prepared. Authors: Dupont, John Neuman 1 ; Minicozzi, Michael J. 1 ; Robino, Charles ...

  7. Ferromagnetic superexchange in insulating Cr2MoO6 by controlling orbital hybridization

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

    Zhu, M.; Do, D.; Dela Cruz, Clarina R.; Dun, Zhiling; Cheng, J. -G.; Goto, H.; Uwatoko, Yoshiya; Zou, T.; Zhou, Haidon D.; Mahanti, Subhendra D.; et al

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr2MoO6. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr2TeO6, Cr2MoO6 possesses a magnetic structure of the Cr2MoO6 type, different from that seen in Cr2TeO6. Ab-initio electronic structure calculations show that the sign and strength of the Cr-O-Cr exchange coupling is strongly influenced by the hybridization between Mo 4d and O 2p orbitals. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of the non-magnetic atoms in the exchange path throughmore » orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.« less

  8. Stability of precipitate phases in Fe-rich Fe-Cr-Ni-Mo alloys

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

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

    2015-01-01

    Understanding the stability of precipitate phases in the Fe-rich Fe-Cr-Ni-Mo alloys is critical to the alloy design and application of Mo-containing Austenitic steels. Coupled with thermodynamic modeling, stability of the and phases in two Fe-Cr-Ni-Mo alloys were investigated at 1000, 850 and 700 C for different annealing time. The morphologies, compositions and crystal structures of the matrix and precipitate phases were carefully examined by Scanning Electron Microscopy, Electron Probe Microanalysis, X-ray diffraction and Transmission Electron Microscopy. Two key findings resulted from this work. One is that the phase is stable at high temperature and transformed into the phase at lowmoretemperature. The other is that both the and phases have large solubilites of Cr, Mo and Ni, among which the Mo solubility has a major role on the relative stability of the precipitate phases. The developed thermodynamic models were then applied to evaluating the Mo effect on the stability of precipitate phases in AISI 316 and NF709 alloys.less

  9. Thermal stability of intermetallic phases in Fe-rich Fe-Cr-Ni-Mo alloys

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

    Yang, Ying; Tan, Lizhen; Busby, Jeremy T.

    2015-06-12

    Understanding the stability of precipitate phases in the Fe-rich Fe-Cr-Ni-Mo alloys is critical to the alloy design and application of Mo-containing Austenitic steels. Coupled with thermodynamic modeling, stability of the chi and Laves phases in two Fe-Cr-Ni-Mo alloys were investigated at 1000, 850 and 700 °C for different annealing time. The morphologies, compositions and crystal structures of the matrix and precipitate phases were carefully examined by Scanning Electron Microscopy, Electron Probe Microanalysis, X-ray diffraction and Transmission Electron Microscopy. The two key findings resulted from this work. One is that the chi phase is stable at high temperature and transformed intomore » the Laves phase at low temperature. The other is that both the chi and Laves phases have large solubilites of Cr, Mo and Ni, among which the Mo solubility has a major role on the relative stability of the precipitate phases. The developed thermodynamic models were then applied to evaluating the Mo effect on the stability of precipitate phases in AISI 316 and NF709 alloys.« less

  10. Thermal stability of intermetallic phases in Fe-rich Fe-Cr-Ni-Mo alloys

    SciTech Connect (OSTI)

    Yang, Ying; Tan, Lizhen; Busby, Jeremy T.

    2015-06-12

    Understanding the stability of precipitate phases in the Fe-rich Fe-Cr-Ni-Mo alloys is critical to the alloy design and application of Mo-containing Austenitic steels. Coupled with thermodynamic modeling, stability of the chi and Laves phases in two Fe-Cr-Ni-Mo alloys were investigated at 1000, 850 and 700 °C for different annealing time. The morphologies, compositions and crystal structures of the matrix and precipitate phases were carefully examined by Scanning Electron Microscopy, Electron Probe Microanalysis, X-ray diffraction and Transmission Electron Microscopy. The two key findings resulted from this work. One is that the chi phase is stable at high temperature and transformed into the Laves phase at low temperature. The other is that both the chi and Laves phases have large solubilites of Cr, Mo and Ni, among which the Mo solubility has a major role on the relative stability of the precipitate phases. The developed thermodynamic models were then applied to evaluating the Mo effect on the stability of precipitate phases in AISI 316 and NF709 alloys.

  11. Thermal aging modeling and validation on the Mo containing Fe-Cr-Ni alloys

    SciTech Connect (OSTI)

    Yang, Ying; Tan, Lizhen; Busby, Jeremy T.

    2015-04-01

    Thermodynamics of intermetallic phases in Fe-rich Fe-Cr-Ni-Mo alloys is critical knowledge to understand thermal aging effect on the phase stability of Mo-containing austenitic steels, which subsequently facilitates alloy design/improvement and degradation mitigation of these materials for reactor applications. Among the intermetallic phases, Chi (χ), Laves, and Sigma (σ) are often of concern because of their tendency to cause embrittlement of the materials. The focus of this study is thermal stability of the Chi and Laves phases as they were less studied compared to the Sigma phase. Coupled with thermodynamic modeling, thermal stability of intermetallic phases in Mo containing Fe-Cr-Ni alloys was investigated at 1000, 850 and 700 C for different annealing times. The morphologies, compositions and crystal structures of the precipitates of the intermetallic phases were carefully examined by scanning electron microscopy, electron probe microanalysis, X-ray diffraction, and transmission electron microscopy. Three key findings resulted from this study. First, the Chi phase is stable at high temperature, and with decreasing temperature it transforms into the Laves phase that is stable at low temperature. Secondly, Cr, Mo, Ni are soluble in both the Chi and Laves phases, with the solubility of Mo playing a major role in the relative stability of the intermetallic phases. Thirdly, in situ transformation from Chi phase to Laves phase was directly observed, which increased the local strain field, generated dislocations in the intermetallic phases, and altered the precipitate phase orientation relationship with the austenitic matrix. The thermodynamic models that were developed and validated were then applied to evaluating the effect of Mo on the thermal stability of intermetallic phases in type 316 and NF709 stainless steels.

  12. Ferromagnetic superexchange in insulating Cr2MoO6 by controlling orbital hybridization

    SciTech Connect (OSTI)

    Zhu, M.; Do, D.; Dela Cruz, Clarina R.; Dun, Zhiling; Cheng, J. -G.; Goto, H.; Uwatoko, Yoshiya; Zou, T.; Zhou, Haidon D.; Mahanti, Subhendra D.; Ke, Xianglin

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr2MoO6. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr2TeO6, Cr2MoO6 possesses a magnetic structure of the Cr2MoO6 type, different from that seen in Cr2TeO6. Ab-initio electronic structure calculations show that the sign and strength of the Cr-O-Cr exchange coupling is strongly influenced by the hybridization between Mo 4d and O 2p orbitals. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of the non-magnetic atoms in the exchange path through orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.

  13. Corrosion and degradation of a polyurethane/Co-Ni-Cr-Mo pacemaker lead

    SciTech Connect (OSTI)

    Sung, P.; Fraker, A.C.

    1987-12-01

    An investigation to study changes in the metal surfaces and the polyurethane insulation of heart pacemaker leads under controlled in vitro conditions was conducted. A polyurethane (Pellethane 2363-80A)/Co-Ni-Cr-Mo (MP35N) wire lead was exposed in Hanks' physiological saline solution for 14 months and then analyzed using scanning electron microscopy, x-ray energy dispersive analysis, and small angle x-ray scattering. Results showed that some leakage of solution into the lead had occurred and changes were present on both the metal and the polyurethane surfaces.

  14. Localized Corrosion of a Neutron Absorbing Ni-Cr-Mo-Gd Alloy

    SciTech Connect (OSTI)

    R.E. Mizia; T. E. Lister; P. J. Pinhero; T. L. Trowbridge

    2005-04-01

    The National Spent Nuclear Fuel Program, located at the Idaho National Laboratory (INL), has developed a new nickel-chromium-molybdenum-gadolinium structural alloy for storage and long-term disposal of spent nuclear fuel (SNF). The new alloy will be used for SNF storage container inserts for nuclear criticality control. Gadolinium has been chosen as the neutron absorption alloying element due to its high thermal neutron absorption cross section. This alloy must be resistant to localized corrosion when exposed to postulated Yucca Mountain in-package chemistries. The corrosion resistance properties of three experimental heats of this alloy are presented. The alloys performance are be compared to Alloy 22 and borated stainless steel. The results show that initially the new Ni-Cr-Mo-Gd alloy is less resistant to corrosion as compared to another Ni-Cr-Mo-Gd alloy (Alloy 22); but when the secondary phase that contains gadolinium (gadolinide) is dissolved, the alloy surface becomes passive. The focus of this work is to qualify these gadolinium containing materials for ASME code qualification and acceptance in the Yucca Mountain Repository.

  15. Nanoscale Phase Separation In Epitaxial Cr-Mo and Cr-V Alloy Thin Films Studied Using Atom Probe Tomography: Comparison Of Experiments And Simulation

    SciTech Connect (OSTI)

    Devaraj, Arun; Kaspar, Tiffany C.; Ramanan, Sathvik; Walvekar, Sarita K.; Bowden, Mark E.; Shutthanandan, V.; Kurtz, Richard J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxial (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation it is very challenging to characterize by conventional techniques. Therefor laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr0.61Mo0.39, Cr0.77Mo0.23, and Cr0.32V0.68 alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were thus confirmed.

  16. Nanoscale phase separation in epitaxial Cr-Mo and Cr-V alloy thin films studied using atom probe tomography: Comparison of experiments and simulation

    SciTech Connect (OSTI)

    Devaraj, A.; Ramanan, S.; Walvekar, S.; Bowden, M. E.; Shutthanandan, V.; Kaspar, T. C.; Kurtz, R. J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxy (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However, the presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation, it is very challenging to characterize by conventional techniques. Therefore, laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr{sub 0.61}Mo{sub 0.39}, Cr{sub 0.77}Mo{sub 0.23}, and Cr{sub 0.32}V{sub 0.68} alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus, the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were confirmed.

  17. Heat treated 9 Cr-1 Mo steel material for high temperature application

    DOE Patents [OSTI]

    Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-08-21

    The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

  18. Thermodynamic modeling and experimental validation of the Fe-Al-Ni-Cr-Mo alloy system

    SciTech Connect (OSTI)

    Teng, Zhenke; Zhang, F; Miller, Michael K; Liu, Chain T; Huang, Shenyan; Chou, Y.T.; Tien, R; Chang, Y A; Liaw, Peter K

    2012-01-01

    NiAl-type precipitate-strengthened ferritic steels have been known as potential materials for the steam turbine applications. In this study, thermodynamic descriptions of the B2-NiAl type nano-scaled precipitates and body-centered-cubic (BCC) Fe matrix phase for four alloys based on the Fe-Al-Ni-Cr-Mo system were developed as a function of the alloy composition at the aging temperature. The calculated phase structure, composition, and volume fraction were validated by the experimental investigations using synchrotron X-ray diffraction and atom probe tomography. With the ability to accurately predict the key microstructural features related to the mechanical properties in a given alloy system, the established thermodynamic model in the current study may significantly accelerate the alloy design process of the NiAl-strengthened ferritic steels.

  19. Microstructural characterization of as-cast biocompatible Co-Cr-Mo alloys

    SciTech Connect (OSTI)

    Giacchi, J.V.; Morando, C.N.; Fornaro, O.; Palacio, H.A.

    2011-01-15

    The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by the investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. This work focuses on the resulting microstructures arising from samples poured under industrial environment conditions, of three different Co-Cr-Mo alloys. For this purpose, we used: 1) an alloy built up from commercial purity constituents, 2) a remelted alloy and 3) a certified alloy for comparison. The characterization of the samples was achieved by using optical microscopy (OM) with a colorant etchant to identify the present phases and scanning electron microscopy (SE-SEM) and energy dispersion spectrometry (EDS) techniques for a better identification. In general the as-cast microstructure is a Co-fcc dendritic matrix with the presence of a secondary phase, such as the M{sub 23}C{sub 6} carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloys. Other minority phases were also reported and their presence could be linked to the cooling rate and the manufacturing process variables and environment. - Research Highlights: {yields}The solidification microstructure of an ASTM-F75 type alloy were studied. {yields}The alloys were poured under an industrial environment. {yields}Carbides and sigma phase identified by color metallography and scanning microscopy (SEM and EDS). {yields}Two carbide morphologies were detected 'blocky type' and 'pearlite type'. {yields}Minority phases were also detected.

  20. Synthesis and mechanical properties of CrMoC{sub x}N{sub 1-x} coatings deposited by a hybrid coating system

    SciTech Connect (OSTI)

    Yun, Ji Hwan; Heo, Su Jeong; Kim, Kwang Ryul; Kim, Kwang Ho

    2008-01-15

    Quaternary CrMoC{sub x}N{sub 1-x} coatings were deposited on steel substrates (AISI D2) and Si wafers by a hybrid coating system combining an arc-ion plating technique and a dc reactive magnetron sputtering technique using Cr and Mo targets in an Ar/N{sub 2}/CH{sub 4} gaseous mixture. The carbon content of CrMoC{sub x}N{sub 1-x} coatings was linearly increased with increasing CH{sub 4}/(CH{sub 4}+N{sub 2}) gas flow rate ratio. The maximum hardness of 44 GPa was obtained from the CrMoC{sub x}N{sub 1-x} coatings containing a carbon content of x=0.33 with a residual stress of -4.4 GPa. The average friction coefficient of Cr-Mo-N coatings was 0.42, and it is decreased to 0.31 after applying CrMoC{sub x}N{sub 1-x} coatings. This result was caused by the formation of a carbon-rich transfer layer that acted as a solid lubricant to reduce contact between the coating surface and steel ball. The microstructure of the coatings was investigated by x-ray diffraction, scanning electron microscopy, and x-ray photoelectron spectroscopy. In this work, the microstructure and mechanical properties of the CrMoC{sub x}N{sub 1-x} coatings were systematically investigated with the instrumental analyses.

  1. Microstructural evolution during solution treatment of Co-Cr-Mo-C biocompatible alloys

    SciTech Connect (OSTI)

    Giacchi, J.V.; Fornaro, O.; Palacio, H.

    2012-06-15

    Three different Co-Cr-Mo-C alloys conforming to ASTM F75 standard were poured in an industrial environment and subjected to a conventional solution treatment at 1225 Degree-Sign C for several time intervals. The microstructural changes and transformations were studied in each case in order to evaluate the way in which treatment time influences the secondary phase fraction and clarify the microstructural changes that could occur. To assess how treatment time affects microstructure, optical microscopy and image analyzer software, scanning electron microscopy and energy dispersion spectrometry analysis were employed. The main phases detected in the as-cast state were: {sigma}-phase, M{sub 6}C, and M{sub 23}C{sub 6} carbides. The latter presented two different morphologies, blocky type and lamellar type. Despite being considered the most detrimental feature to mechanical properties, {sigma}-phase and lamellar carbides dissolution took place in the early stages of solution treatment. M{sub 23}C{sub 6} carbides featured two different behaviors. In the alloy obtained by melting an appropriate quantity of alloyed commercial materials, a decrease in size, spheroidization and transformation into M{sub 6}C carbides were simultaneously observed. In the commercial ASTM F75 alloy, in turn, despite being the same phase, only a marked decrease in precipitates size was noticed. These different behaviors could be ascribed to the initial presence of other phases in the alloy obtained from alloyed materials, such as {sigma}-phase and 'pearlitic' carbides, or to the initial precipitate size which was much larger in the first than in the commercial ASTM F75 alloy studied. M{sub 6}C carbides dissolved directly in the matrix as they could not be detected in samples solution-treated for 15 min. - Highlights: Black-Right-Pointing-Pointer Three different Co-Cr-Mo alloys were poured under an industrial environment. Black-Right-Pointing-Pointer Transformation of existing phases followed during conventional solution treatment. Black-Right-Pointing-Pointer In as-cast/treated samples, phases were identified by color metallography, SEM and EDS. Black-Right-Pointing-Pointer M{sub 23}C{sub 6} {yields} M{sub 6}C transformation was corroborated by SEM and EDS analysis. Black-Right-Pointing-Pointer Carbide spheroidization was also detected prior a noticeably carbide size decreasing.

  2. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    SciTech Connect (OSTI)

    Xu, Z.

    2012-04-03

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  3. Comparison of Crevice Corrosion of Fe-Based Amorphous Metal and Crystalline Ni-Cr-Mo Alloy

    SciTech Connect (OSTI)

    Shan, X; Ha, H; Payer, J H

    2008-07-24

    The crevice corrosion behaviors of an Fe-based bulk metallic glass alloy (SAM1651) and a Ni-Cr-Mo crystalline alloy (C-22) were studied in 4M NaCl at 100 C with cyclic potentiodynamic polarization and constant potential tests. The corrosion damage morphologies, corrosion products and the compositions of corroded surfaces of these two alloys were studied with optical 3D reconstruction, Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Auger Electron Spectroscopy (AES). It was found that the Fe-based bulk metallic glass (amorphous alloy) SAM1651 had a more positive breakdown potential and repassivation potential than crystalline alloy C-22 in cyclic potentiodynamic polarization tests and required a more positive oxidizing potential to initiate crevice corrosion in constant potential test. Once crevice corrosion initiated, the corrosion propagation of C-22 was more localized near the crevice border compared to SAM1651, and SAM1651 repassivated more readily than C-22. The EDS results indicated that the corrosion products of both alloys contained high amount of O and were enriched in Mo and Cr. The AES results indicated that a Cr-rich oxide passive film was formed on the surfaces of both alloys, and both alloys were corroded congruently.

  4. Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Teactor Pressure Vessels

    SciTech Connect (OSTI)

    Potirniche, Gabriel; Barlow, Fred D.; Charit, Indrajit; Rink, Karl

    2013-11-26

    A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: • Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions. • Perform creep tests and characterize the mechanisms of creep fracture process. • Quantify how the microstructure degradation controls the creep strength of welded steel specimens. • Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds. • Develop a microstructure-based creep fracture model to estimate RPVs service life . • Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates. • Simulate damage evolution in creep specimens by FE analyses. • Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage. • Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength. • Develop a fracture model for the structural integrity of RPVs subjected to creep loads. • Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

  5. Microstructure investigation of 13Cr-2Mo ODS steel components obtained by high voltage electric discharge compaction technique

    SciTech Connect (OSTI)

    Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene

    2015-11-02

    Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining the initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.

  6. Temperature-dependent phase-specific deformation mechanisms in a directionally solidified NiAl-Cr(Mo) lamellar composite

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

    Yu, Dunji; An, Ke; Chen, Xu; Bei, Hongbin

    2015-10-09

    Phase-specific thermal expansion and mechanical deformation behaviors of a directionally solidified NiAl–Cr(Mo) lamellar in situ composite were investigated by using real-time in situ neutron diffraction during compression at elevated temperatures up to 800 °C. Tensile and compressive thermal residual stresses were found to exist in the NiAl phase and Crss (solid solution) phase, respectively. Then, based on the evolution of lattice spacings and phase stresses, the phase-specific deformation behavior was analyzed qualitatively and quantitatively. Moreover, estimates of phase stresses were derived by Hooke's law on the basis of a simple method for the determination of stress-free lattice spacing in inmore » situ composites. During compressive loading, the NiAl phase yields earlier than the Crss phase. The Crss phase carries much higher stress than the NiAl phase, and displays consistent strain hardening at all temperatures. The NiAl phase exhibits strain hardening at relatively low temperatures and softening at high temperatures. During unloading, the NiAl phase yields in tension whereas the Crss phase unloads elastically. Additionally, post-test microstructural observations show phase-through cracks at room temperature, micro cracks along phase interfaces at 600 °C and intact lamellae kinks at 800 °C, which is due to the increasing deformability of both phases as temperature rises.« less

  7. Microstructure investigation of 13Cr-2Mo ODS steel components obtained by high voltage electric discharge compaction technique

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

    Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene

    2015-11-02

    Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining themore » initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.« less

  8. Evaluation of ferritic alloy Fe-2-1/4Cr-1Mo after neutron irradiation - microstructure development

    SciTech Connect (OSTI)

    Gelles, D.S.

    1984-05-01

    Microstructural examinations are reported for nine specimen conditions of 2-1/4Cr-1Mo steel which had been irradiated by fast neutrons over the temperature range 390 to 510/sup 0/C. Two heats of material were involved, each with a different preirradiation heat treatment, one irradiated to a peak fluence of 5.1 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV) or 24 dpa and the other to 2.4 x 10/sup 23/ n/cm/sup 2/ (E > 0.1 MeV) or 116 dpa. Void swelling is found following irradiation at 400/sup 0/C in both conditions and to 480/sup 0/C in the higher fluence conditions. Concurrently dislocation structure and precipitation formed. Peak void swelling, void density, dislocation density and precipitate number density developed at the lowest temperature, approx. 400/sup 0/C, whereas mean void size, and mean precipitate size increased with increasing irradiation temperature. The examination results are used to provide interpretation of in-reactor creep, density change and post irradiation tensile behavior.

  9. Thermal expansion of Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12} solid solutions

    SciTech Connect (OSTI)

    Ari, M.; Jardim, P.M.; Marinkovic, B.A. Rizzo, F.; Ferreira, F.F.

    2008-06-15

    The transition temperature from monoclinic to orthorhombic and the thermal expansion of the orthorhombic phase were investigated for three systems of the family A{sub 2}M{sub 3}O{sub 12}: Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12}. It was possible to obtain a single-phase solid solution in all studied samples (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1). A linear relationship between the transition temperature and the fraction of A{sup 3+} cations (x) was observed for each system. In all orthorhombic solid solutions studied here the observed thermal expansion was anisotropic. These anisotropic thermal expansion properties of crystallographic axes a, b and c result in a low positive or near-zero overall linear coefficient of thermal expansion ({alpha}{sub l}={alpha}{sub V}/3). The relationship between the size of A{sup 3+} cations in A{sub 2}M{sub 3}O{sub 12} and the coefficient of thermal expansion is discussed. Near-zero thermal expansion of Cr{sub 2}Mo{sub 3}O{sub 12} is explained by the behavior of Cr-O and Mo-O bond distances, Cr-Mo non-bond distances and Cr-O-Mo bond angles with increasing temperature, estimated by Rietveld analysis of synchrotron X-ray powder diffraction data. - Graphical abstract: In this figure, all published overall linear coefficients of thermal expansion for orthorhombic A{sub 2}M{sub 3}O{sub 12} family obtained through diffraction methods as a function of A{sup 3+} cation radii size, together with dilatometric results, are plotted. Our results indicate that Cr{sub 2}Mo{sub 3}O{sub 12} does not exactly follow the established relationship.

  10. Evaluation of 2.25Cr-1Mo Alloy for Containment of LiCl/KCl Eutectic during the Pyrometallurgical Processing of Used Nuclear Fuel

    SciTech Connect (OSTI)

    B.R. Westphal; S.X. Li; G.L. Fredrickson; D. Vaden; T.A. Johnson; J.C. Wass

    2011-03-01

    Recovery of uranium from the Mk-IV and Mk-V electrorefiner vessels containing a LiCl/KCl eutectic salt has been on-going for 14 and 12 years, respectively, during the pyrometallurgical processing of used nuclear fuel. Although austenitic stainless steels are typically utilized for LiCl/KCl salt systems, the presence of cadmium in the Mk-IV electrorefiner dictates an alternate material. A 2.25Cr-1Mo alloy (ASME SA-387) was chosen due to the absence of nickel in the alloy which has a considerable solubility in cadmium. Using the transition metal impurities (iron, chromium, nickel, molybdenum, and manganese) in the electrorefined uranium products, an algorithm was developed to derive values for the contribution of the transition metals from the various input sources. Weight loss and corrosion rate data for the Mk-V electrorefiner vessel were then generated based on the transition metal impurities in the uranium products. To date, the corrosion rate of the 2.25Cr-1Mo alloy in LiCl/KCl eutectic is outstanding assuming uniform (i.e. non-localized) conditions.

  11. Photoredox degradation of different water pollutants (MO, RhB, MB, and Cr(VI)) using Fe–N–S-tri-doped TiO{sub 2} nanophotocatalyst prepared by novel chemical method

    SciTech Connect (OSTI)

    Xu, Xuyao; Zhou, Xiaosong Zhang, Lingling; Xu, Limei; Ma, Lin; Luo, Jin; Li, Mengjia; Zeng, Lihua

    2015-10-15

    Highlights: • TiO{sub 2} was synthesized through simple one-step hydrothermal method. • Photocatalytic activity for degradation of organic dyes and Cr(VI) are investigated. • The synergistic effect is shown in coexistence of MB and Cr(VI). - Abstract: Fe–N–S-tri-doped TiO{sub 2} (FeNS-TiO{sub 2}) was synthesized by a simple one-step hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of as-synthesized samples were tested by the oxidation of methyl orange (MO), rhodamine B (RhB), methylene blue (MB) and the reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation, and compared with N-dope P25 (N-P25) and the undoped TiO{sub 2}. Besides, the effects of the coexistence of MO, RhB, and MB on FeNS-TiO{sub 2}-mediated photocatalytic reduction of aqueous Cr(VI) were also studied. The results indicated FeNS-TiO{sub 2} displayed higher visible-light-activated photocatalytic activity than N-P25 and the undoped TiO{sub 2}. Otherwise, FeNS-TiO{sub 2} showed the coexistence of MB enhanced the photocatalytic reduction of Cr(VI), whereas the coexistence of MO and RhB retarded the photocatalytic reduction of Cr(VI) over FeNS-TiO{sub 2}. Moreover, a possible photocatalytic mechanism is discussed.

  12. Influence of microstructural changes due to tempering at 923 K and 1,023 K on magnetic Barkhausen noise behavior in normalized 2.25Cr-1Mo ferritic steel

    SciTech Connect (OSTI)

    Raj, B.; Moorthy, V.; Vaidyanathan, S.

    1997-01-01

    Magnetic Barkhausen noise analysis has been used to characterize the microstructural changes in normalized and tempered 2.25 Cr-1Mo steel. It is observed that tempering at 923 K shows a single peak behavior up to 20 h and tempering at 1,023 K shows a two peak behavior. This has been explained on the basis of the two stage process of irreversible domain wall movement during magnetization, associated with two major obstacles to domain wall movement: namely lath/grain boundaries and secondary phase precipitates. At lower fields, existing reverse domain walls at lath/grain boundaries overcome the resistance offered by the grain boundaries and move to a distance before they are pined by the precipitates. Then, at higher field, they overcome these precipitates. These two processes occur over a range of critical field strengths with some mean values. If these two mean values are close to each other, then a single peak in the rms voltage of the magnetic Barkhausen noise, with the associated changes in its shape, is observed. On the other hand, if the mean values of the critical fields for these two barriers are widely separated, then a two peak behavior is the clear possibility. The effect of the microstructural changes due to tempering for different durations at 923 K and 1,023 K in 2.25 Cr-1Mo ferritic steel on magnetic Barkhausen noise is explained based on these two stage processes. The influence of high dislocation density in bainitic structure, dissociation of bainite, and precipitation of different carbides such as Fe{sub 3}C, Mo{sub 2}C, Cr{sub 7}Ce{sub 3}, M{sub 23}C{sub 6}, etc., on magnetic Barkhausen noise behavior has been analyzed in this study.

  13. Formation of voids and secondary-phase precipitates in the Fe-16Cr-15Ni-2Mo-1Mn-Ti-Si steel under high-doze neutron irradiation and during post-irradiation annealing

    SciTech Connect (OSTI)

    Portnykh, I. A. Kozlov, A. V.; Shcherbakov, E. N.; Asiptsov, O. I.

    2009-12-15

    The effect of high-dose neutron irradiation on the structural changes in Fe-16Cr-15Ni-2Mo-1Mn-Ti-Si austenitic steel have been investigated. Samples irradiated at temperatures of 390, 500, and 600{sup o} to damage doses of 46, 86, and 46 dpa, respectively, were analyzed by electron microscopy and dilatometry. The quantitative characteristics of radiation voids and secondary-phase precipitates formed under neutron irradiation are obtained. Their behavior upon heating to 700{sup o}C and annealing at this temperature for 2 h is studied. It is shown that annealing leads to the dissociation of small voids, which is accompanied by the growth of large ones. The secondary-phase precipitates are partially dissolved upon annealing, and their volume fraction decreases.

  14. Mo-99

    National Nuclear Security Administration (NNSA)

    its project for domestic production of molybdenum-99 (Mo-99) without highly enriched uranium (HEU).

    Mo-99 is the parent isotope of technetium-99m, which is the most widely...

  15. Mo-99

    National Nuclear Security Administration (NNSA)

    NorthStar Medical Radioisotopes to further develop its technology to produce Mo-99 via neutron capture, bringing the total NNSA support to this project to the maximum of 25...

  16. MO: ZL

    Office of Legacy Management (LM)

    II , --fsi2L /~YlO MO: ZL W./O -1 ;3UN 2 2 1984 DeLanr 6/W/f. NE-20 -24 Authorization for Remedial Action at the Seaway Industrial Park and Ashland 0 1 Co. (I) Sites at Tonawanda, 9 NY, and Mallinckrodt Chemical Co., St. Louis, MO Ba 1s J. LaGrone, Eianager Oak Ridge Operations Office 6/20/E We have determined that the subject sites are contaminated with residual NE-20 radioactive material as a result of the Manhattan Engineer District/Atomic ,/"/1. EnergyXommission operations at those

  17. Quantification of corrosion resistance of a new-class of criticality control materials: thermal-spray coatings of high-boron iron-based amorphous metals - Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4

    SciTech Connect (OSTI)

    Farmer, J C; Choi, J S; Shaw, C K; Rebak, R; Day, S D; Lian, T; Hailey, P; Payer, J H; Branagan, D J; Aprigliano, L F

    2007-03-28

    An iron-based amorphous metal, Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} (SAM2X5), with very good corrosion resistance was developed. This material was produced as a melt-spun ribbon, as well as gas atomized powder and a thermal-spray coating. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation. The high boron content of this particular amorphous metal made it an effective neutron absorber, and suitable for criticality control applications. Earlier studies have shown that ingots and melt-spun ribbons of these materials have good passive film stability in these environments. Thermal spray coatings of these materials have now been produced, and have undergone a variety of corrosion testing, including both atmospheric and long-term immersion testing. The modes and rates of corrosion have been determined in the various environments, and are reported here.

  18. MongoDB

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

    MongoDB MongoDB Description and Overview MongoDB is a cross-platform document-oriented database. Classified as a NoSQL database, MongoDB eschews the traditional table-based relational database structure in favor of JSON-like documents with dynamic schemas, making the integration of data in certain types of applications easier and faster. NERSC provides a set of MongoDB nodes for users that wish to use MongoDB with their scientific applications. How to Use MongoDB The MongoDB command line client

  19. Fragile structural transition in Mo3Sb7

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

    Yan, Jiaqiang -Q.; McGuire, Michael A; May, Andrew F; Parker, David S.; Mandrus, D. G.; Sales, Brian C.

    2015-01-01

    Mo3Sb7 single crystals lightly doped with Cr, Ru, or Te are studied in order to explore the interplay between superconductivity, magnetism, and the cubic-tetragonal structural transition. The structural transition at 53 K is extremely sensitive to Ru or Te substitution which introduces additional electrons, but robust against Cr substitution. We observed no sign of a structural transition in superconducting Mo2.91Ru0.09Sb7 and Mo3Sb6.975Te0.025. In contrast, 3 at.% Cr doping only slightly suppresses the structural transition to 48 K while leaving no trace of superconductivity above 1.8 K. Analysis of magnetic properties suggests that the interdimer interaction in Mo3Sb7 is near amore » critical value and essential for the structural transition. Futhermore, all dopants suppress the superconductivity of Mo3Sb7. The tetragonal structure is not necessary for superconductivity.« less

  20. Dual-phase Cr-Ta alloys for structural applications

    DOE Patents [OSTI]

    Liu, Chain T.; Brady, Michael P.; Zhu, Jiahong; Tortorelli, Peter F.

    2001-01-01

    Dual phase alloys of chromium containing 2 to 11 atomic percent tantalum with minor amounts of Mo, Cr, Ti, Y, La, Cr, Si and Ge are disclosed. These alloys contain two phases including Laves phase and Cr-rich solid solution in either eutectic structures or dispersed Laves phase particles in the Cr-rich solid solution matrix. The alloys have superior mechanical properties at high temperature and good oxidation resistance when heated to above 1000.degree. C. in air.

  1. Nanocrystallization in spark plasma sintered Fe{sub 48}Cr{sub 15}Mo{sub 14}Y{sub 2}C{sub 15}B{sub 6} bulk amorphous alloy

    SciTech Connect (OSTI)

    Singh, Ashish; Harimkar, Sandip P.; Katakam, Shravana; Dahotre, Narendra B.; Ilavsky, Jan

    2013-08-07

    Spark plasma sintering (SPS) is evolving as an attractive process for the processing of multi-component Fe-based bulk amorphous alloys and their in-situ nanocomposites with controlled primary nanocrystallization. Extended Q-range small angle neutron scattering (EQ-SANS) analysis, complemented by x-ray diffraction and transmission electron microscopy, was performed to characterize nanocrystallization behavior of SPS sintered Fe-based bulk amorphous alloys. The SANS experiments show significant scattering for the samples sintered in the supercooled region indicating local structural/compositional changes associated with the profuse nucleation of nanoclusters (∼4 nm). For the samples spark plasma sintered near and above crystallization temperature (>653 °C), the SANS data show the formation of interference maximum indicating the formation and growth of (Fe,Cr){sub 23}C{sub 6} crystallites. The SANS data also indicate the evolution of bimodal crystallite distribution at higher sintering temperatures (above T{sub x1}). The growth of primary nanocrystallites results in impingement of concentration gradient fields (soft impingement effect), leading to non-random nucleation of crystallites near the primary crystallization.

  2. Effect of La{sub 2}O{sub 3}, CoO, Cr{sub 2}O{sub 3} and MoO{sub 3} nucleating agents on crystallization behavior and magnetic properties of ferromagnetic glass-ceramic in the system Fe{sub 2}O{sub 3}{center_dot}CaO{center_dot}ZnO{center_dot}SiO{sub 2}

    SciTech Connect (OSTI)

    Abdel-Hameed, Salwa A.M.; Elwan, Rawhia L.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Crystallization of magnetic glass ceramic with different nucleating agents. Black-Right-Pointing-Pointer The effect of La{sub 2}O{sub 3}, CoO, Cr{sub 2}O{sub 3} and MoO{sub 3} as nucleating agents was studied. Black-Right-Pointing-Pointer XRD for as prepared samples revealed crystallization of pure magnetite. Black-Right-Pointing-Pointer Heat treatment revealed minor calcium silicate, hematite and cristobalite. Black-Right-Pointing-Pointer TEM revealed crystallization of crystallite size in the range 50-100 nm. -- Abstract: Preparation and characterization of ferromagnetic glass ceramic in the system Fe{sub 2}O{sub 3}{center_dot}CaO{center_dot}ZnO{center_dot}SiO{sub 2} with different nucleating agents was studied. The effect of La{sub 2}O{sub 3}, CoO, Cr{sub 2}O{sub 3} and MoO{sub 3} as nucleating agents was investigated. Differential thermal analysis; X-ray diffraction and transmission electron microscope were used to investigate thermal behavior, sequence of crystallization and microstructure of the samples. XRD analysis for as prepared samples revealed the crystallization of single magnetite phase. Heat treatment at 900 Degree-Sign C/2 h revealed the appearance of minor amounts of calcium silicate, hematite and cristobalite beside magnetite. TEM revealed crystallization of crystallite size in the range 50-100 nm. Lattice parameters, cell volume and crystallite size were stimulated from XRD data. Magnetic properties of quenched samples were measured under 20 kG.

  3. SciDB

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

    Screen Shot 2014 03 15 at 12.06.05 AM Bird's Eye View - SciDB Testbed at NERSC Pioneers High Usability Big Data Analytic Infrastructure. Motivation? It's painful to manage and ...

  4. Computational prediction and characterization of single-layer CrS{sub 2}

    SciTech Connect (OSTI)

    Zhuang, Houlong L.; Blonsky, Michael N.; Hennig, Richard G.; Johannes, Michelle D.

    2014-01-13

    Using first-principles calculations, we predict a previously unreported bulk CrS{sub 2} phase that is stable against competing phases and a low energy dynamically stable single-layer CrS{sub 2} phase. We characterize the electronic, optical, and piezoelectric properties of this single-layer material. Like single-layer MoS{sub 2}, CrS{sub 2} has a direct bandgap and valley polarization. The optical bandgap of CrS{sub 2} is 1.3?eV, close to the ideal bandgap of 1.4?eV for photovoltaic applications. Applying compressive strain increases the bandgap and optical absorbance, transforming it into a promising photocatalyst for solar water splitting. Finally, we show that single-layer CrS{sub 2} possesses superior piezoelectric properties to single-layer MoS{sub 2}.

  5. US WNC MO Site Consumption

    U.S. Energy Information Administration (EIA) Indexed Site

    WNC MO Site Consumption million Btu $0 $500 $1,000 $1,500 $2,000 $2,500 US WNC MO Expenditures dollars ALL ENERGY average per household (excl. transportation) 0 3,000 6,000 9,000 12,000 15,000 US WNC MO Site Consumption kilowatthours $0 $300 $600 $900 $1,200 $1,500 US WNC MO Expenditures dollars ELECTRICITY ONLY average per household * Missouri households consume an average of 100 million Btu per year, 12% more than the U.S. average. * Average household energy costs in Missouri are slightly less

  6. Fragile structural transition in Mo3Sb7

    SciTech Connect (OSTI)

    Yan, Jiaqiang -Q.; McGuire, Michael A; May, Andrew F; Parker, David S.; Mandrus, D. G.; Sales, Brian C.

    2015-08-10

    Mo3Sb7 single crystals lightly doped with Cr, Ru, or Te are studied in order to explore the interplay between superconductivity, magnetism, and the cubic-tetragonal structural transition. The structural transition at 53 K is extremely sensitive to Ru or Te substitution which introduces additional electrons, but robust against Cr substitution. We observed no sign of a structural transition in superconducting Mo2.91Ru0.09Sb7 and Mo3Sb6.975Te0.025. In contrast, 3 at.% Cr doping only slightly suppresses the structural transition to 48 K while leaving no trace of superconductivity above 1.8 K. Analysis of magnetic properties suggests that the interdimer interaction in Mo3Sb7 is near a critical value and essential for the structural transition. Futhermore, all dopants suppress the superconductivity of Mo3Sb7. The tetragonal structure is not necessary for superconductivity.

  7. LANS DB PENSION PLAN

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

    LANS Contract LANS Contract Information Management and Operating Contract for the Los Alamos National Laboratory For confirmation of Official Contract Provisions, call: Dan Saiz, Contract Specialist, M&O Contract Support Division at (505) 845-4024. Get Adobe Reader You will need Adobe Acrobat to read many of the files on this site. If you haven't already done so, please download the free Adobe Reader

    December 2010 u:\my documents\pension plan\revised tcp1 db plan spd dec 2010.doc LANS

  8. Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications

    SciTech Connect (OSTI)

    Klueh, R.L.; Maziasz, P.J.; Vitek, J.M.; Evans, N.D.; Hashimoto, N.

    2006-09-23

    Economic and environmental concerns demand that the power-generation industry seek increased efficiency for gas turbines. Higher efficiency requires higher operating temperatures, with the objective temperature for the hottest sections of new systems {approx} 593 C, and increasing to {approx} 650 C. Because of their good thermal properties, Cr-Mo-V cast ferritic steels are currently used for components such as rotors, casings, pipes, etc., but new steels are required for the new operating conditions. The Oak Ridge National Laboratory (ORNL) has developed new wrought Cr-W-V steels with 3-9% Cr, 2-3% W, 0.25% V (compositions are in wt.%), and minor amounts of additional elements. These steels have the strength and toughness required for turbine applications. Since cast alloys are expected to behave differently from wrought material, work was pursued to develop new cast steels based on the ORNL wrought compositions. Nine casting test blocks with 3, 9, and 11% Cr were obtained. Eight were Cr-W-V-Ta-type steels based on the ORNL wrought steels; the ninth was COST CB2, a 9Cr-Mo-Co-V-Nb cast steel, which was the most promising cast steel developed in a European alloy-development program. The COST CB2 was used as a control to which the new compositions were compared, and this also provided a comparison between Cr-W-V-Ta and Cr-Mo-V-Nb compositions. Heat treatment studies were carried out on the nine castings to determine normalizing-and-tempering treatments. Microstructures were characterized by both optical and transmission electron microscopy (TEM). Tensile, impact, and creep tests were conducted. Test results on the first nine cast steel compositions indicated that properties of the 9Cr-Mo-Co-V-Nb composition of COST CB2 were better than those of the 3Cr-, 9Cr-, and 11Cr-W-V-Ta steels. Analysis of the results of this first iteration using computational thermodynamics raised the question of the effectiveness in cast steels of the Cr-W-V-Ta combination versus the Cr-Mo-V-Nb combination in COST CB2. To explore this question, nine more casting test blocks, four 3Cr steels and five 11Cr steels were purchased, and microstructure and mechanical properties studies similar to those described above for the first iteration of test blocks were conducted. Experimental results from the second iteration indicated that 11 Cr steels with excellent properties are possible. The 11Cr-1.5Mo-V-Nb steels were superior to 11Cr-2W-V-Ta steels, and it appears the former class of steels can be developed to have tensile and creep properties exceeding those of COST CB2. The W-Nb combination in an 11Cr-2W-V-Nb steel had tensile and short-time creep properties at 650 C better than the 11Cr-1.5Mo-V-Nb steels, although long-time low-stress properties may not be as good because of Laves phase formation. Based on the results, the next step in the development of improved casting steels involves acquisition of 11Cr-1.5Mo-V-Nb-N-B-C and 11Cr-2W-V-Nb-N-B-C steels on which long-term creep-rupture tests (>10,000 h) be conducted. For better oxidation and corrosion resistance, development of 11Cr steels, as opposed to a 9Cr steels, such as COST CB2, are important for future turbine designs that envision operating temperatures of 650 C.

  9. Mo#va#on

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

    = a n i nherent l imita#ons of both: h ot & c old f usion r eac#ons: Hot (well--- d eformed r adioac1ve ac1nides ( Act.) t argets a re u sed a nd compound n ucleus i s q uite e xcited ) * a8empts o f g oing b eyond the r eac#ons A ct. + 48 Ca b y using h eavier p rojec#les l ike 50 Ti, 54 Cr, 58 Fe, a nd 64 Ni gave n o r esults s o f ar. * all h eavier a c#nides w ith Z>98 l ive t o s hort t hat o ne could p erform t arget w ith them. Cold ( magic n uclei a s t argets a re u sed w ith

  10. d::;":,",:::,, ST. LOUIS.7. MO,

    Office of Legacy Management (LM)

    i ,' CKRODT CHEMICAL d::;":,",:::,, ST. LOUIS.7. MO, PiARCH 14, ,jq;ll MR. H. L. PRICE, ... I AL PERAT I ONS DF MALL- INCKRODT ' CHEMICAL b:ORKS WOULD LIKE TO MAKE.APPLlCATlON ...

  11. DB Climate Change Advisors DBCCA | Open Energy Information

    Open Energy Info (EERE)

    DB Climate Change Advisors DBCCA Jump to: navigation, search Name: DB Climate Change Advisors (DBCCA) Place: New York, New York Product: New York-based climate change investement...

  12. Optimization of the Processing of Mo Disks

    SciTech Connect (OSTI)

    Tkac, Peter; Rotsch, David A.; Stepinski, Dominique; Makarashvili, Vakhtang; Harvey, James; Vandegrift, George F.

    2016-01-01

    The objective of this work is to decrease the processing time for irradiated disks of enriched Mo for the production of 99Mo. Results are given for the dissolution of nonirradiated Mo disks, optimization of the process for large-scale dissolution of sintered disks, optimization of the removal of the main side products (Zr and Nb) from dissolved targets, and dissolution of irradiated Mo disks.

  13. SSL Demonstration: Street Lighting, Kansas City, MO

    SciTech Connect (OSTI)

    2013-08-01

    GATEWAY program report brief summarizing an SSL street lighting demonstration at nine separate installations in Kansas City, MO.

  14. DB-Netz AG Offices

    High Performance Buildings Database

    Hamm, Germany The new office building for DB Netz AG was designed by the collaborative team of Architrav Architects and the Buildings Physics and Technical Building Services group of the University of Karlsruhe. The team developed an energy efficient building concept for the 64,304 sqft office building, located in Hamm, Germany. The design concept of the building is dominated by architectural solutions for ventilation, cooling and lighting. Use of HVAC and electric lighting is minimized as much as possible.

  15. DOE - Office of Legacy Management -- Washington University - MO 07

    Office of Legacy Management (LM)

    Washington University - MO 07 FUSRAP Considered Sites Site: WASHINGTON UNIVERSITY (MO.07 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: St. Louis , Missouri MO.07-1 Evaluation Year: 1987 MO.07-1 Site Operations: Activities were limited to programs involving relatively small quantities of radionuclides and chemicals in a controlled environment. MO.07-3 MO.07-1 Site Disposition: Eliminated - Potential for contamination remote MO.07-1

  16. Microsoft Word - CR.doc

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

    in XAS studies a. Porewater Na and Nitrate b. Water Extractable and Sorbed Cr c. In-situ Temperature Depth Below Ground Surface (m) Figure 1. Solute concentration profiles in core...

  17. Mo99 Production Plant Layout

    SciTech Connect (OSTI)

    Woloshun, Keith Albert; Dale, Gregory E.; Naranjo, Angela Carol

    2015-06-25

    The NorthStar Medical Technologies 99Mo production facility configuration is envisioned to be 8 accelerator pairs irradiating 7 100Mo targets (one spare accelerator pair undergoing maintenance while the other 7 pairs are irradiating targets). The required shielding in every direction for the accelerators is initially estimated to be 10 feet of concrete. With the accelerator pairs on one (ground) level and spaced with the required shielding between adjacent pairs, the only practical path for target insertion and removal while minimizing floor space is vertical. The current scheme then requires a target vertical lift of nominally 10 feet through a shield stack. It is envisioned that the lift will be directly into a hot cell where an activated target can be removed from its holder and a new target attached and lowered. The hot cell is on a rail system so that a single hot cell can service all active target locations, as well as deliver the ready targets to the separations lab. On this rail system, coupled to the hot cell, will be a helium recovery and clean-up system. All helium coolant equipment is located on the upper level near to the target removal point.

  18. DOE - Office of Legacy Management -- Spencer Chemical Co - MO...

    Office of Legacy Management (LM)

    MO 0-01 FUSRAP Considered Sites Site: SPENCER CHEMICAL CO. (MO.0-01) Eliminated from ... Also see Documents Related to SPENCER CHEMICAL CO. MO.0-01-1 - Spencer Chemical Company ...

  19. DOE - Office of Legacy Management -- St Louis Airport - MO 01

    Office of Legacy Management (LM)

    Operations: Stored uranium process residues containing uranium, radium, and thorium for the MED and AEC. MO.01-2 MO.01-3 MO.01-4 Eligibility Determination: Eligible ...

  20. Synthesis and characterization of Cr-doped ZnO nanorod-array photocatalysts with improved activity

    SciTech Connect (OSTI)

    Chang, Chi-Jung Yang, Tsung-Lin; Weng, Yu-Ching

    2014-06-01

    Immobilized photocatalysts with high catalytic activity under UV light were prepared by growing Cr-doped ZnO nanorods on glass substrates by a hydrothermal method. The effects of Cr dopant on the surface texture, crystallinity, surface chemistry, and photoinduced charge separation and their relation with the photocatalytic degradation of Cr-doped ZnO were investigated by scanning electron microscopy, diffuse reflectance spectra, photoelectrochemical scanning electrochemical microscopy, and X-ray photoemission spectroscopy. Adding the appropriate amount of Cr dopant is a powerful way to enhance the separation of charge carriers in ZnO photocatalyst. The photocatalytic activity was improved due to the increase in surface oxygen vacancies, the separation of charge carriers, modification of the band gap, and the large surface area of the doped ZnO nanorod photocatalyst. - Graphical abstract: Photoinduced charge separation and its relation with the photocatalytic degradation activity of Cr-doped ZnO were investigated by photoelectrochemical scanning electrochemical microscopy. - Highlights: Cr dopant enhances separation of charge carries in ZnO nanorod photocatalyst. Photoinduced charge carries separation monitored by PEC-SECM. The higher the photocurrent is, the higher the photocatalytic activity is. Degradation of DB86 dye solutions under visible light finished within 50 min. Higher activity due to more oxygen vacancy, tuned band gap and more surface area.

  1. Preliminary Results on FeCrAl Alloys in the As-received and Welded State Designed to Have Enhanced Weldability and Radiation Tolerance

    SciTech Connect (OSTI)

    Field, Kevin G.; Gussev, Maxim N.; Hu, Xunxiang; Yamamoto, Yukinori

    2015-09-30

    The present report summarizes and discusses the recent results on developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability. The alloys used for these investigations are modern FeCrAl alloys based on a Fe-13Cr-5Al-2Mo-0.2Si-0.05Y alloy (in wt.%, designated C35M). Development efforts have focused on assessing the influence of chemistry and microstructure on the fabricability and performance of these newly developed alloys. Specific focus was made to assess the weldability, thermal stability, and radiation tolerance.

  2. Update to M&O Contractor Model Subcontract entitled "Standard...

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

    to M&O Contractor Model Subcontract entitled "Standard Research Subcontract (Educational Institution or Nonprofit Organization)" Update to M&O Contractor Model Subcontract entitled ...

  3. Tuning the electronic structure of monolayer graphene/ Mo S 2...

    Office of Scientific and Technical Information (OSTI)

    Tuning the electronic structure of monolayer graphene Mo S 2 van der Waals ... Title: Tuning the electronic structure of monolayer graphene Mo S 2 van der Waals ...

  4. Missouri Department of National Resources Energy Center Mo DNR...

    Open Energy Info (EERE)

    Department of National Resources Energy Center Mo DNR Jump to: navigation, search Name: Missouri Department of National Resources Energy Center (Mo DNR) Place: Jefferson City,...

  5. DOE - Office of Legacy Management -- United Nuclear Corp - MO...

    Office of Legacy Management (LM)

    Nuclear Corp - MO 0-03 FUSRAP Considered Sites Site: UNITED NUCLEAR CORP. (MO.0-03) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate ...

  6. Demonstration of LED Street Lighting in Kansas City, MO (Technical...

    Office of Scientific and Technical Information (OSTI)

    Demonstration of LED Street Lighting in Kansas City, MO Citation Details In-Document Search Title: Demonstration of LED Street Lighting in Kansas City, MO Nine different ...

  7. DOE - Office of Legacy Management -- West Lake Landfill - MO...

    Office of Legacy Management (LM)

    Lake Landfill - MO 05 FUSRAP Considered Sites Site: West Lake Landfill (MO.05) Designated Name: Alternate Name: Location: Evaluation Year: Site Operations: Site Disposition:...

  8. The performance of cermet cutting tools when machining an Ni-Cr-Mo (En 24) steel

    SciTech Connect (OSTI)

    Ezugwu, E.O.; Lim, S.K.

    1995-02-01

    Recently developed grades of cermet cutting tool materials, physical vapor deposition (PVD)-coated and uncoated, were used to machine a high-strength and relatively difficult-to-cut steel at cutting conditions typical of finish machining. Comparative tests were carried out with chemical vapor deposition (CVD)-coated (TiC + Al{sub 2}O{sub 3}) carbide inserts at similar cutting conditions. The test results show that the PVD-coated cermet tools outperformed both the uncoated cermet and CVD-coated carbide tools at higher speed conditions due to their increased mechanical and thermal shock resistance as well as the high lubricity of the TiN coating layer. The coated cermet tools were rejected mainly due to the generation of poor surface finish on the machined surface after prolonged machining due to the increased tool-workpiece contact area, with increasing flank wear, which permits access for dislodged hard particles into the interface. Plastic deformation of the cutting edge of the coated cermet tools tends to dampen the machining operation, leading to a reduction in both the cutting and feed forces. 9 refs., 10 figs., 1 tab.

  9. Thermophysical Properties of U-10MO Alloy

    SciTech Connect (OSTI)

    A. M. Phillips; G. S. Mickum; D. E. Burkes

    2010-11-01

    This report provides an overview of thermophysical properties of unirradiated uranium alloyed with ten weight percent molybdenum (U 10Mo), with particular focus on those material properties needed for modeling of new fuels for HPRRs (High Performance Research Reactors). The report contains both historical data available in the literature on U-10Mo, as well as more recent results conducted by the Global Threat Reduction Initiative fuel development program. The main use of the report is intended as a standard U-10Mo alloy properties reference for reactor models and simulations.

  10. Mo Year Report Period: EIA ID NUMBER:

    U.S. Energy Information Administration (EIA) Indexed Site

    Mo Year Report Period: EIA ID NUMBER: http:www.eia.govsurveyformeia14instructions.pdf Mailing Address: Secure File Transfer option available at: (e.g., PO Box, RR) https:...

  11. Release on M&O Selection Final

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

    Federal Services LLC, of Bethesda, Maryland) has been awarded a 1.3 billion contract for management and operating (M&O) at DOE's Waste Isolation Pilot Plant (WIPP) in Carlsbad,...

  12. Advanced ODS FeCrAl alloys for accident-tolerant fuel cladding

    SciTech Connect (OSTI)

    Dryepondt, Sebastien N; Unocic, Kinga A; Hoelzer, David T; Pint, Bruce A

    2014-09-01

    ODS FeCrAl alloys are being developed with optimum composition and properties for accident tolerant fuel cladding. Two oxide dispersion strengthened (ODS) Fe-15Cr-5Al+Y2O3 alloys were fabricated by ball milling and extrusion of gas atomized metallic powder mixed with Y2O3 powder. To assess the impact of Mo on the alloy mechanical properties, one alloy contained 1%Mo. The hardness and tensile properties of the two alloys were close and higher than the values reported for fine grain PM2000 alloy. This is likely due to the combination of a very fine grain structure and the presence of nano oxide precipitates. The nano oxide dispersion was however not sufficient to prevent grain boundary sliding at 800 C and the creep properties of the alloys were similar or only slightly superior to fine grain PM2000 alloy. Both alloys formed a protective alumina scale at 1200 C in air and steam and the mass gain curves were similar to curves generated with 12Cr-5Al+Y2O3 (+Hf or Zr) ODS alloys fabricated for a different project. To estimate the maximum temperature limit of use for the two alloys in steam, ramp tests at a rate of 5 C/min were carried out in steam. Like other ODS alloys, the two alloys showed a significant increase of the mas gains at T~ 1380 C compared with ~1480 C for wrought alloys of similar composition. The beneficial effect of Yttrium for wrought FeCrAl does not seem effective for most ODS FeCrAl alloys. Characterization of the hardness of annealed specimens revealed that the microstructure of the two alloys was not stable above 1000 C. Concurrent radiation results suggested that Cr levels <15wt% are desirable and the creep and oxidation results from the 12Cr ODS alloys indicate that a lower Cr, high strength ODS alloy with a higher maximum use temperature could be achieved.

  13. Using SciDB to Support Photon Science Data Analysis

    SciTech Connect (OSTI)

    Becla, Jack; Wang, Daniel; lim, Kian-Tat; /SLAC

    2012-02-15

    Array data analytic systems like SciDB hold great potential to accelerate processing data from SLAC's Linac Coherent Light Source and other experiments. SciDB is unique in its ability to integrate storage and processing of array data efficiently, providing both space-efficient storage and out-of-memory efficient parallel array processing. We describe a recent effort to leverage SciDB to store and process LCLS data. The work includes development of software to import data into SciDB, subsequent benchmarks, and interactive manipulation of data in SciDB.

  14. Effect of Austenization Temperature on the Microstructure and Strength of 9% and 12% Cr Ferritic-Martensitic Steels

    SciTech Connect (OSTI)

    Terry C. Totemeier

    2004-10-01

    The effect of reduced-temperature austenization on the microstructure and strength of two ferritic-martensitic steels was studied. Prototypic 9% and 12% Cr steels, grade 91 (9Cr-1MoVNb) and type 422 stainless (12Cr-1MoVW), respectively, were austenized at 925C and 1050C and tempered at 760C. The reduced austenization temperature was intended to simulate potential inadequate austenization during field construction of large structures and also the thermal cycle experienced in the Type IV region of weld heat affected zones (HAZ). The microstructure, tensile behavior, and creep strength were characterized for both steels treated at each condition. The reduced austenization temperature resulted in general coarsening of carbides in both steels and polygonization of the tempered martensite structure in type 422. For this steel, a marked reduction in microhardness was observed, while there was little change in microhardness for grade 91. Slight reductions in tensile strength were observed for both steels at room temperature and elevated temperatures of 450 and 550C. The strength reduction was greater for type 422 than for grade 91. At 650C the tensile strength reduction was minimal for both steels. Marked reductions in creep rupture lives were observed for both steels at 650C; the reductions were less at 600C and minimal at 550C. Overall, the higher Cr content steel was observed to be more sensitive to variations in heat treatment conditions.

  15. Supercondutivity at 9K in Mo5PB2 with evidence for multiple gaps

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

    McGuire, Michael A.; Parker, David S.

    2016-02-09

    Superconductivity is observed with critical temperatures near 9 K in the tetragonal compound Mo5PB2. This material adopts the Cr5B3 structure type common to superconducting Nb5Si3–xBx, Mo5SiB2, and W5SiB2, which have critical temperatures of 5.8–7.8 K. We have synthesized polycrystalline samples of the compound, made measurements of electrical resistivity, magnetic susceptibility, and heat capacity, and performed first-principles electronic structure calculations. The highest Tc value (9.2 K) occurs in slightly phosphorus rich samples, with composition near Mo5P1.1B1.9, and the upper critical field Hc2 at T = 0 is estimated to be ≈17 kOe. Together, the measurements and band-structure calculations indicate intermediate couplingmore » (λ=1.0), phonon mediated superconductivity. Here, the temperature dependence of the heat capacity and upper critical field Hc2 below Tc suggest multiple superconducting gaps may be present.« less

  16. Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

    SciTech Connect (OSTI)

    Schulthess, Jason

    2014-09-01

    Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

  17. Oxidation, Reduction, and Condensation of Alcohols over (MO3)3 (M=Mo, W) Nanoclusters

    SciTech Connect (OSTI)

    Fang, Zongtang; Li, Zhenjun; Kelley, Matthew S.; Kay, Bruce D.; Li, Shenggang; Hennigan, Jamie M.; Rousseau, Roger J.; Dohnalek, Zdenek; Dixon, David A.

    2014-10-02

    The reactions of deuterated methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-butanol and t-butanol over cyclic (MO3)3 (M = Mo, W) clusters were studied experimentally with temperature programmed desorption (TPD) and theoretically with coupled cluster CCSD(T) theory and density functional theory. The reactions of two alcohols per M3O9 cluster are required to provide agreement with experiment for D2O release, dehydrogenation and dehydration. The reaction begins with the elimination of water by proton transfers and forms an intermediate dialkoxy species which can undergo further reaction. Dehydration proceeds by a ? hydrogen transfer to a terminal M=O. Dehydrogenation takes place via an ? hydrogen transfer to an adjacent MoVI = O atom or a WVI metal center with redox involved for M = Mo and no redox for M = W. The two channels have comparable activation energies. H/D exchange to produce alcohols can take place after olefin is released or via the dialkoxy species depending on the alcohol and the cluster. The Lewis acidity of the metal center with WVI being larger than MoVI results in the increased reactivity of W3O9 over Mo3O9 for dehydrogenation and dehydration.

  18. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, T.W.; Lograsso, T.A.; Eshelman, M.A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate. 7 figs.

  19. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, Timothy W.; Lograsso, Thomas A.; Eshelman, Mark A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate.

  20. Oxidation resistance of 9-12% Cr steels: effect of rare earth surface treatment

    SciTech Connect (OSTI)

    Dogan, Omer N.; Alman, David A.; Jablonski, Paul D.

    2005-02-01

    Medium Cr steels have been used in fossil fired power plants for many years because of their excellent high temperature stability and mechanical properties. The environment in a fossil fired power plant is extremely aggressive in terms of corrosion, especially oxidation. This is only accelerated as the operating temperature increases to 650C and beyond. For any new steel to be qualified for power plant use, in addition to adequate strength at the operating temperature, material wastage from all corrosion processes must be kept to a minimum acceptable level. The use of medium Cr steels provides a means to improve overall corrosion resistance. Three medium Cr are under development for use as high temperature power plant steels: 0.08C-(9-12)Cr-1.2Ni-0.7Mo-3.0Cu-3.0Co-0.5Ti. Oxidation tests were performed on the steels for times greater than 1000 hours in order to determine the oxidation kinetics and extent of material wastage. Also, rare earth oxides were incorporated into the outer surface layers of the steels to see if the oxidation resistance could be improved. These results will be compared to current power plant steels.

  1. Nucleation of Cr precipitates in Fe-Cr alloy under irradiation

    SciTech Connect (OSTI)

    Dai, Y. Y.; Ao, L.; Sun, Qing- Qiang; Yang, L.; Nie, JL; Peng, SM; Long, XG; Zhou, X. S.; Zu, Xiaotao; Liu, L.; Sun, Xin; Terentyev, Dimtry; Gao, Fei

    2015-04-01

    The nucleation of Cr precipitates induced by overlapping of displacement cascades in Fe-Cr alloys has been investigated using the combination of molecular dynamics (MD) and Metropolis Monte Carlo (MMC) simulations. The results reveal that the number of Frenkel pairs increases with the increasing of overlapped cascades. Overlapping cascades could promote the formation of Cr precipitates in Fe-Cr alloys, as analyzed using short range order (SRO) parameters to quantify the degree of ordering and clustering of Cr atoms. In addition, the simulations using MMC approach show that the presence of small Cr clusters and vacancy clusters formed within cascade overlapped region enhance the nucleation of Cr precipitates, leading to the formation of large Cr dilute precipitates.

  2. DOE - Office of Legacy Management -- Latty Avenue Site - MO 04

    Office of Legacy Management (LM)

    MO.04-1 - DOE Letter; Keller to Jarboe; Subject: Agreement for Use of Property at 9200 Latty Avenue, Hazelwood, Missouri; November 22, 1983 MO.04-10 - DOE Report (ORNLRASA-857); ...

  3. DOE - Office of Legacy Management -- Rogers Iron Works Co - MO...

    Office of Legacy Management (LM)

    of Ohio Analytical Data Sheet 9908; August 2, 1956 MO.10-2 - MemorandumChecklist, Williams to File; Subject: Rogers Iron; June 1, 1990 MO.10-3 - DOE Memorandum; Williams to the...

  4. Accelerator Production Options for 99MO

    SciTech Connect (OSTI)

    Bertsche, Kirk; /SLAC

    2010-08-25

    Shortages of {sup 99}Mo, the most commonly used diagnostic medical isotope, have caused great concern and have prompted numerous suggestions for alternate production methods. A wide variety of accelerator-based approaches have been suggested. In this paper we survey and compare the various accelerator-based approaches.

  5. NERSC Accelerates Scientific Analysis with SciDB

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

    NERSC Accelerates Scientific Analysis with SciDB NERSC Accelerates Scientific Analysis with SciDB August 26, 2015 Linda Vu, +1 510 495 2402, lvu@lbl.gov Pic-from-posterrevised-1.jpg SciDB harnesses parallel architectures for fast analysis of terabyte (TBs) arrays of scientific data. This collage illustrates some of the scientific areas that have benefited from NERSC's implementation of SciDB, including astronomy, biology and climate. (Image Credit: Yushu Yao, Berkeley Lab) Science is swimming in

  6. MOED_of_the_Italian_Republic.PDF | Department of Energy

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

    MOED_of_the_Italian_Republic.PDF MOED_of_the_Italian_Republic.PDF PDF icon MOED_of_the_Italian_Republic.PDF More Documents & Publications Scanned_Agreement.pdf International_Agreements_January_2001_December_2004.pdf Implementing Arrangement Between DOE and METI on R&D Cooperation on Clean Energy Technology - April 2015

  7. Intermetallic phase formation and breakdown of Mo diffusion barriers in Ni-Mo-Cu and Ni-Mo-Monel 400 diffusion triads

    SciTech Connect (OSTI)

    Shueh, Y.

    1988-01-01

    The purpose of this research was to study the kinetics of compound formation and the interdiffusion behavior of a sacrificial type diffusion barrier in a model system. Ni-Mo diffusion couples were annealed in an inert atmosphere at 950-1050{degree}C for 5-300 hours. Ni-Mo-Cu and Ni-Mo-Monel 400 diffusion triads with varied thicknesses of Mo layers sandwiched by Ni and C or Monel 400 disks were annealed under the same conditions. Parabolic growth of the intermetallic phase, {beta}, was observed at 1000{degree}C and 1050{degree}C in the semi-infinite Ni-Mo diffusion couple an din the Ni-Mo-Cu diffusion triad when a finite thickness of the Mo layer remained. The {beta} phase exhibited more or less planar morphology except in the case of some extremely rugged interfaces which were associated with grain boundaries adjacent to these interfaces. Dissociation and recession of the compound layer in Ni-Mo-Cu diffusion triads initiated when the Mo layer was nearly consumed. The product phases of the dissociation reaction are consistent with those predicted from the Ni-Mo-Cu ternary phase diagram. Numerical methods based on a finite difference technique, and an analytical solution based on diffusion controlled parabolic growth and quasi-steady-state approximation in the {beta} phase region were used to analyze the results.

  8. Role of SrMoO{sub 4} in Sr{sub 2}MgMoO{sub 6} synthesis

    SciTech Connect (OSTI)

    Vasala, S.; Yamauchi, H.; Karppinen, M.

    2011-05-15

    Here we investigate the elemental and phase compositions during the solid-state synthesis of the promising SOFC-anode material, Sr{sub 2}MgMoO{sub 6}, and demonstrate that molybdenum does not notably evaporate under the normal synthesis conditions with temperatures up to 1200 {sup o}C due to the formation of SrMoO{sub 4} as an intermediate product at low temperatures, below 600 {sup o}C. However, partial decomposition of the Sr{sub 2}MgMoO{sub 6} phase becomes evident at the higher temperatures ({approx}1500 {sup o}C). The effect of SrMoO{sub 4} on the electrical conductivity of Sr{sub 2}MgMoO{sub 6} is evaluated by preparing a series of Sr{sub 2}MgMoO{sub 6} samples with different amounts of additional SrMoO{sub 4}. Under the reducing operation conditions of an SOFC anode the insulating SrMoO{sub 4} phase is apparently reduced to the highly conductive SrMoO{sub 3} phase. Percolation takes place with 20-30 wt% of SrMoO{sub 4} in a Sr{sub 2}MgMoO{sub 6} matrix, with a notable increase in electrical conductivity after reduction. Conductivity values of 14, 60 and 160 S/cm are determined at 800 {sup o}C in 5% H{sub 2}/Ar for the Sr{sub 2}MgMoO{sub 6} samples with 30, 40 and 50 wt% of added SrMoO{sub 4}, respectively. -- Graphical abstract: SrMoO{sub 4} is formed at low temperatures during the synthesis of Sr{sub 2}MgMoO{sub 6}, which prevents the volatilization of Mo from typical precursor mixtures of this promising SOFC anode material. SrMoO{sub 4} is insulating and it is often found as an impurity in Sr{sub 2}MgMoO{sub 6} samples. It is however readily reduced to highly conducting SrMoO{sub 3}. Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show increased electrical conductivities compared to pure Sr{sub 2}MgMoO{sub 6} under the reductive operation conditions of an SOFC anode. Display Omitted Highlights: {yields} Sr{sub 2}MgMoO{sub 6} is a promising SOFC anode material. {yields} During the Sr{sub 2}MgMoO{sub 6} synthesis SrMoO{sub 4} is formed at low temperatures. {yields} Formation of SrMoO{sub 4} effectively prevents volatilization of Mo at high temperatures. {yields} Insulating SrMoO{sub 4} reduces to highly conductive SrMoO{sub 3} under SOFC-anode conditions. {yields} Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show high electrical conductivities.

  9. Structural analysis of Cr aggregation in ferromagnetic semiconductor (Zn,Cr)Te

    SciTech Connect (OSTI)

    Kobayashi, H.; Yamawaki, K.; Nishio, Y.; Kanazawa, K.; Kuroda, S.; Mitome, M.; Bando, Y.

    2013-12-04

    The Cr aggregation in a ferromagnetic semiconductor (Zn,Cr)Te was studied by performing precise analyses using TEM and XRD of microscopic structure of the Cr-aggregated regions formed in iodine-doped Zn{sub 1?x}Cr{sub x}Te films with a relatively high Cr composition x ? 0.2. It was found that the Cr-aggregated regions are composed of Cr{sub 1??}Te nanocrystals of the hexagonal structure and these hexagonal precipitates are stacked preferentially on the (111)A plane of the zinc-blende (ZB) structure of the host ZnTe crystal with its c-axis nearly parallel to the (111){sub ZB} plane.

  10. PASSBY(with FitToDB)

    Energy Science and Technology Software Center (OSTI)

    2002-08-28

    The PASSBY program is used to operate the Sensor for Measurement and analysis of radiation transients (SMART). The unit records triggers an "Event" upon detecting an increase in count rate recorded with a sodium iodide gamma-ray spectrometer. Background radiation levels are monitored continuously and background spectra are updated at 60 second intervals if no radiation sources are present other than those in the natural background. the system accepts input from an optional neutron counter. Inmore » addition to spectral information, the location, determined with an internal GPS and the compass bearing are reported via either an RF modem or a serial cable. The gamma-ray spectra are analyzed to determine which isotopes are present and confidence levels are assigned. The analysis is performed using the FitToDB algorithm, is described as follows. The automatic identification algorithm FitToDB algorithm enables the automatic identification of gamma-ry emitting isotopes in shielded sources. FitToDB can identify combinations of up to ten isotopes, each of which may be viewed through different shielding materials. The algorithm runs rapidly (within about 3 seconds on a 100 MHz Pentium-class processor), and can be compiled to run both DOS and Windows operating systems. Computational speed and system interoperability issues are addressed by the approach of interpolating spectra from an existing database of computed templates rather than performing detector response functions calculations within the algorithm.« less

  11. Mo-99 | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Mo-99 DOE/NNSA Successfully Establishes Uranium Lease and Takeback Program to Support Critical Medical Isotope Production In January 2016, the U.S. Department of Energy's National Nuclear Security Administration (DOE/NNSA) successfully established the Uranium Lease and Take-Back (ULTB) program, as directed in the American Medical Isotopes Production Act of 2012, to support the commercial production of the medical... NNSA's work aids in fight against cancer World Cancer Day encourages citizens

  12. Creep and oxidation behavior of modified CF8C-plus with W, Cu, Ni, and Cr

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

    Unocic, Kinga A.; Dryepondt, Sebastien N.; Yamamoto, Yukinori; Maziasz, Philip J.

    2016-02-01

    Here, the microstructures of modified CF8C-Plus (Fe-19Cr-12Ni-0.4W-3.8Mn-0.2Mo-0.6Nb-0.5Si-0.9C) with W and Cu (CF8CPWCu) and CF8CPWCu enhanced with 21Cr + 15Ni or 22Cr + 17.5Ni were characterized in the as-cast condition and after creep testing. When imaged at lower magnifications, the as-cast microstructure was similar among all three alloys as they all contained a Nb-rich interdendritic phase and Mn-based inclusions. Transmission electron microscopy (TEM) analysis showed the presence of nanoscale Cu-rich nanoprecipitates distributed uniformly throughout the matrix of CF8CPWCu, whereas in CF8CPWCu22/17, Cu precipitates were found primarily at the grain boundaries. The presence of these nanoscale Cu-rich particles, in addition to W-richmore » Cr23C6, nanoscale Nb carbides, and Z-phase (Nb2Cr2N2), improved the creep strength of the CF8CPWCu steel. Modification of CF8CPWCu with Cr and Ni contents slightly decreased the creep strength but significantly improved the oxidation behavior at 1073 K (800 °C). In particular, the addition of 22Cr and 17.5Ni strongly enhanced the oxidation resistance of the stainless steel resulting in a 100 degrees or greater temperature improvement, and this composition provided the best balance between improving both mechanical properties and oxidation resistance.« less

  13. Midea: ENERGY STAR Referral (MWF-08CR)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Westpointe-brand room air conditioner model MWF-08CR to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  14. Emerson: ENERGY STAR Referral (CR289E)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Emerson-brand refrigerator, model CR289E, to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  15. NNSA Awards Mo-99 Cooperative Agreement to General Atomics | National

    National Nuclear Security Administration (NNSA)

    Nuclear Security Administration Library / Press Releases NNSA Awards Mo-99 Cooperative Agreement to General Atomics September 30, 2015 WASHINGTON, DC - Today, the Department of Energy's National Nuclear Security Administration (DOE/NNSA) announced that it will award a cooperative agreement to General Atomics (GA) to support its project for domestic production of molybdenum-99 (Mo-99) without highly enriched uranium (HEU). Mo-99 is the parent isotope of technetium-99m, which is the most

  16. A COMPREHENSIVE SPECTROSCOPIC ANALYSIS OF DB WHITE DWARFS

    SciTech Connect (OSTI)

    Bergeron, P.; Wesemael, F.; Dufour, Pierre; Beauchamp, A.; Hunter, C.; Gianninas, A.; Limoges, M.-M.; Dufour, Patrick; Fontaine, G. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Saffer, Rex A. [Strayer University, 234 Mall Boulevard, Suite G-50, King of Prussia, PA 19406 (United States); Ruiz, M. T. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Liebert, James, E-mail: bergeron@astro.umontreal.ca, E-mail: wesemael@astro.umontreal.ca, E-mail: gianninas@astro.umontreal.ca, E-mail: limoges@astro.umontreal.ca, E-mail: dufourpa@astro.umontreal.ca, E-mail: fontaine@astro.umontreal.ca, E-mail: alain.beauchamp@fti-ibis.com, E-mail: chris.hunter@yale.edu, E-mail: rex.saffer@strayer.edu, E-mail: mtruiz@das.uchile.cl [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2011-08-10

    We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 M{sub sun} for our sample, with a dispersion of only 0.09 M{sub sun}. White dwarfs also showing hydrogen lines, the DBA stars, comprise 44% of our sample, and their mass distribution appears similar to that of DB stars. As in our previous investigation, we find no evidence for the existence of low-mass (M < 0.5 M{sub sun}) DB white dwarfs. We derive a luminosity function based on a subset of DB white dwarfs identified in the Palomar-Green Survey. We show that 20% of all white dwarfs in the temperature range of interest are DB stars, although the fraction drops to half this value above T{sub eff} {approx} 20,000 K. We also show that the persistence of DB stars with no hydrogen features at low temperatures is difficult to reconcile with a scenario involving accretion from the interstellar medium, often invoked to account for the observed hydrogen abundances in DBA stars. We present evidence for the existence of two different evolutionary channels that produce DB white dwarfs: the standard model where DA stars are transformed into DB stars through the convective dilution of a thin hydrogen layer and a second channel where DB stars retain a helium atmosphere throughout their evolution. We finally demonstrate that the instability strip of pulsating V777 Her white dwarfs contains no non-variables, if the hydrogen content of these stars is properly accounted for.

  17. DOE - Office of Legacy Management -- Petrolite Corp - MO 08

    Office of Legacy Management (LM)

    Materials Handled: Yes Primary Radioactive Materials Handled: Uranium Flouride & Thorium Oxide MO.08-2 Radiological Survey(s): None Indicated Site Status: Eliminated from ...

  18. Demonstration of LED Street Lighting in Kansas City, MO Kinzey...

    Office of Scientific and Technical Information (OSTI)

    Street Lighting in Kansas City, MO Kinzey, Bruce R.; Royer, Michael P.; Hadjian, M.; Kauffman, Rick LED streetlighting; field illuminance measurement LED streetlighting; field...

  19. Predicting sigma formation in mo-bearing stainless steels. (Conference...

    Office of Scientific and Technical Information (OSTI)

    Title: Predicting sigma formation in mo-bearing stainless steels. No abstract prepared. Authors: Perricone, Matthew ; Dupont, John Neuman ; Anderson, T. D. 1 ; Robino, Charles ...

  20. MoRu/Be multilayers for extreme ultraviolet applications

    DOE Patents [OSTI]

    Bajt, Sasa C.; Wall, Mark A.

    2001-01-01

    High reflectance, low intrinsic roughness and low stress multilayer systems for extreme ultraviolet (EUV) lithography comprise amorphous layers MoRu and crystalline Be layers. Reflectance greater than 70% has been demonstrated for MoRu/Be multilayers with 50 bilayer pairs. Optical throughput of MoRu/Be multilayers can be 30-40% higher than that of Mo/Be multilayer coatings. The throughput can be improved using a diffusion barrier to make sharper interfaces. A capping layer on the top surface of the multilayer improves the long-term reflectance and EUV radiation stability of the multilayer by forming a very thin native oxide that is water resistant.

  1. Structure and electronic properties of Cu nanoclusters supported on Mo2C(001) and MoC(001) surfaces

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

    Posada-Pérez, Sergio; Viñes, Francesc; Rodríguez, José A.; Illas, Francesc

    2015-09-15

    In this study, the atomic structure and electronic properties of Cun nanoclusters (n = 4, 6, 7, and 10) supported on cubic nonpolar δ-MoC(001) and orthorhombic C- or Mo-terminated polar β-Mo2C(001) surfaces have been investigated by means of periodic density functional theory based calculations. The electronic properties have been analyzed by means of the density of states, Bader charges, and electron localization function plots. The Cu nanoparticles supported on β-Mo2C(001), either Mo- or C-terminated, tend to present a two-dimensional structure whereas a three-dimensional geometry is preferred when supported on δ-MoC(001), indicating that the Mo:C ratio and the surface polarity playmore » a key role determining the structure of supported clusters. Nevertheless, calculations also reveal important differences between the C- and Mo-terminated β-Mo2C(001) supports to the point that supported Cu particles exhibit different charge states, which opens a way to control the reactivity of these potential catalysts.« less

  2. NERSC Accelerates Scientific Analysis with SciDB

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

    build SciDB into their normal science workflows, with the assumption that the lessons learned from each case study would provide insight into how to create new technologies and...

  3. Microstructural and mechanical characteristics of Ni–Cr thin films

    SciTech Connect (OSTI)

    Petley, Vijay; Sathishkumar, S.; Thulasi Raman, K.H.; Rao, G.Mohan; Chandrasekhar, U.

    2015-06-15

    Highlights: • Ni–Cr thin films of varied composition deposited by DC magnetron co-sputtering. • Thin film with Ni–Cr: 80–20 at% composition exhibits most distinct behavior. • The films were tensile tested and exhibited no cracking till the substrate yielding. - Abstract: Ni–Cr alloy thin films have been deposited using magnetron co-sputtering technique at room temperature. Crystal structure was evaluated using GIXRD. Ni–Cr solid solution upto 40 at% of Cr exhibited fcc solid solution of Cr in Ni and beyond that it exhibited bcc solid solution of Ni in Cr. X-ray diffraction analysis shows formation of (1 1 1) fiber texture in fcc and (2 2 0) fiber texture in bcc Ni–Cr thin films. Electron microscopy in both in-plane and transverse direction of the film surface revealed the presence of columnar microstructure for films having Cr upto 40 at%. Mechanical properties of the films are evaluated using nanoindentation. The modulus values increased with increase of Cr at% till the film is fcc. With further increase in Cr at% the modulus values decreased. Ni–Cr film with 20 at% Ni exhibits reduction in modulus and is correlated to the poor crystallization of the film as reflected in XRD analysis. The Ni–Cr thin film with 80 at% Ni and 20 at% Cr exhibited the most distinct columnar structure with highest electrical resistivity, indentation hardness and elastic modulus.

  4. Neutrino scattering off the stable even-even Mo isotopes

    SciTech Connect (OSTI)

    Balasi, K. G.; Kosmas, T. S.; Divari, P. C. [Theoretical Physics Section, University of Ioannina, GR 45110 Ioannina (Greece)

    2009-11-09

    Inelastic neutrino-nucleus reaction cross sections are studied focusing on the neutral current processes. Particularly, we investigate the angular and initial neutrino-energy dependence of the differential and integrated cross sections for low and intermediate energies of the incoming neutrino. The nuclear wave functions for the initial and final nuclear states are constructed in the context of the quasi-particle random phase approximation (QRPA) tested on the reproducibility of the low-lying energy spectrum. The results presented here refer to the isotopes Mo{sup 92}, Mo{sup 94}, Mo{sup 96}, Mo{sup 98} and Mo{sup 100}. These isotopes could play a significant role in supernova neutrino detection in addition to their use in double-beta and neutrinoless double-beta decay experiments (e.g. MOON, NEMO III)

  5. Morphology, deformation, and defect structures of TiCr{sub 2} in Ti-Cr alloys

    SciTech Connect (OSTI)

    Chen, K.C.; Allen, S.M.; Livingston, J.D.

    1992-12-31

    The morphologies and defect structures of TiCr{sub 2} in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr{sub 2}. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability.

  6. Rotationally Commensurate Growth of MoS[subscript 2] on Epitaxial...

    Office of Scientific and Technical Information (OSTI)

    Rotationally Commensurate Growth of MoSsubscript 2 on Epitaxial Graphene Citation Details In-Document Search Title: Rotationally Commensurate Growth of MoSsubscript 2 on ...

  7. Mo-O bond doping and related-defect assisted enhancement of photoluminescence in monolayer MoS{sub 2}

    SciTech Connect (OSTI)

    Wei, Xiaoxu; Yu, Zhihao; Cheng, Ying; Yu, Linwei; Wang, Junzhuan Wang, Xinran; Shi, Yi; Hu, Fengrui; Wang, Xiaoyong; Xiao, Min

    2014-12-15

    In this work, we report a strong photoluminescence (PL) enhancement of monolayer MoS{sub 2} under different treatments. We find that by simple ambient annealing treatment in the range of 200?C to 400?C, the PL emission can be greatly enhanced by a factor up to two orders of magnitude. This enhancement can be attributed to two factors: first, the formation of Mo-O bonds during ambient exposure introduces an effective p-doping in the MoS{sub 2} layer; second, localized electrons formed around Mo-O bonds related defective sites where the electrons can be effectively localized with higher binding energy resulting in efficient radiative excitons recombination. Time resolved PL decay measurement showed that longer lifetime of the treated sample consistent with the higher quantum efficiency in PL. These results give more insights to understand the luminescence properties of the MoS{sub 2}.

  8. Kinetics and Mechanism of the Hydrogenation of CpCr(CO)3/[CpCr(CO)3]2 Equilibrium to CpCr(CO)3H

    SciTech Connect (OSTI)

    Norton, Jack R.; Spataru, Tudor; Camaioni, Donald M.; Lee, Suh-Jane; Li, Gang; Choi, Jongwook; Franz, James A.

    2014-05-26

    The kinetics of the hydrogenation of 2 CpCr(CO)3/[CpCr(CO)3]2 to CpCr(CO)3H has been investigated. The reaction is second-order in Cr and first-order in H2, with a rate constant of 45 M 2s 1 at 25 C in benzene. DFT calculations rule out an H2 complex as an intermediate, and suggest (a) end-on approach of H2 to one Cr of [CpCr(CO)3]2 as the Cr-Cr bond undergoes heterolytic cleavage, (b) heterolytic cleavage of the coordinated H2 between O and Cr, and (c) isomerization of the resulting O-protonated CpCr(CO)2(COH) to CpCr(CO)3H. The work at Pacific Northwest National Laboratory (PNNL) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences; Battelle operates PNNL for DOE.

  9. Hazard Evaluation for 244-CR Vault

    SciTech Connect (OSTI)

    GRAMS, W.H.

    1999-08-19

    This document presents the results of a hazards identification and evaluation performed on the 244-CR Vault to close a USQ (USQ No.TF-98-0785, Potential Inadequacy in Authorization Basis (PIAB): To Evaluate Miscellaneous Facilities Listed In HNF-2503 And Not Addressed In The TWRS Authorization Basis) that was generated as part of an evaluation of inactive TWRS facilities.

  10. A novel three dimensional semimetallic MoS{sub 2}

    SciTech Connect (OSTI)

    Tang, Zhen-Kun; Zhang, Hui; Liu, Li-Min; Liu, Hao; Lau, Woon-Ming

    2014-05-28

    Transition metal dichalcogenides (TMDs) have many potential applications, while the performances of TMDs are generally limited by the less surface active sites and the poor electron transport efficiency. Here, a novel three-dimensional (3D) structure of molybdenum disulfide (MoS{sub 2}) with larger surface area was proposed based on first-principle calculations. 3D layered MoS{sub 2} structure contains the basal surface and joint zone between the different nanoribbons, which is thermodynamically stable at room temperature, as confirmed by first principles molecular dynamics calculations. Compared the two-dimensional layered structures, the 3D MoS{sub 2} not only owns the large surface areas but also can effectively avoid the aggregation. Interestingly, although the basal surface remains the property of the intrinsic semiconductor as the bulk MoS{sub 2}, the joint zone of 3D MoS{sub 2} exhibits semimetallic, which is derived from degenerate 3d orbitals of the Mo atoms. The high stability, large surface area, and high conductivity make 3D MoS{sub 2} have great potentials as high performance catalyst.

  11. Attachment I CHPRC CONDITION REPORT FORM Status: Analysis CR NUMBER: CR-2011I 2037

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

    CHPRC CONDITION REPORT FORM Status: Analysis CR NUMBER: CR-2011I 2037 Issue Identification and Processing Initiator: Initiating IDetifed Bannister, Roland J Document: 6/23/2011d Title of Issue: Extent of Condition review for S3000 containers Description of Issue: Extent of Condition Review arose from the Causal Analysis regarding the breached drum found in 2404WB on April 26, 2011. The scope of the review was to assess all other known S3000 (homogenous solids) waste streams to identify

  12. Polystyrene/MoS{sub 2}@oleylamine nanocomposites

    SciTech Connect (OSTI)

    Altavilla, Claudia; Ciambelli, Paolo; Fedi, Filippo; Sorrentino, Andrea; Iannace, Salvatore

    2014-05-15

    The effects of adding different concentrations of MoS{sub 2}@oleylamine nano particles on the thermal and mechanical properties of polystyrene (PS) nanocomposites have been investigated. X-ray diffraction and optical microscopy were used to characterize the morphology of the resulting nanocomposites. The thermal stability of the nanocomposites has been characterized by thermogravimetric analysis. It has been found that the MoS{sub 2}@oleylamine nanoparticles have a good compatibility with the PS matrix forming homogeneous dispersion even at high concentrations. The PS/MoS{sub 2}@oleylamine nanocomposites showed enhanced thermal stability in comparison with neat polystyrene.

  13. Slow Mo Guys and Cold Spray | GE Global Research

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

    Slow Mo Guys and Cold Spray Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new window) Click to share on LinkedIn (Opens in new window) Click to share on Tumblr (Opens in new window) Slow Mo Guys and Cold Spray ) The Slow Mo Guys came to GE Global Research in Niskayuna to film our researchers demonstrate a process called "cold spray", in which metal powders are sprayed at high velocities to build a part or add

  14. 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.

  15. Letter Report Documenting Progress of Second Generation ATF FeCrAl Alloy Fabrication

    SciTech Connect (OSTI)

    Yamamoto,, Y.; Yang, Y.; Field, K. G.; Terrani, K.; Pint, B. A.; Snead, L. L.

    2014-06-10

    Development of the 2nd generation ATF FeCrAl alloy has been initiated, and a candidate alloy was selected for trial tube fabrication through hot-extrusion and gun-drilling processes. Four alloys based on Fe-13Cr-4.5Al-0.15Y in weight percent were newly cast with minor alloying additions of Mo, Si, Nb, and C to promote solid-solution and second-phase precipitate strengthening. The alloy compositions were selected with guidance from computational thermodynamic tools. The lab-scale heats of ~ 600g were arc-melted and drop-cast, homogenized, hot-forged and -rolled, and then annealed producing plate shape samples. An alloy with Mo and Nb additions (C35MN) processed at 800°C exhibits very fine sub-grain structure with the sub-grain size of 1-3μm which exhibited more than 25% better yield and tensile strengths together with decent ductility compared to the other FeCrAl alloys at room temperature. It was found that the Nb addition was key to improving thermal stability of the fine sub-grain structure. Optimally, grains of less than 30 microns are desired, with grains up to and order of magnitude in desired produced through Nb addition. Scale-up effort of the C35MN alloy was made in collaboration with a commercial cast company who has a capability of vacuum induction melting. A 39lb columnar ingot with ~81mm diameter and ~305mm height (with hot-top) was commercially cast, homogenized, hot-extruded, and annealed providing 10mm-diameter bar-shape samples with the fine sub-grain structure. This commercial heat proved consistent with materials produced at ORNL at the lab-scale. Tubes and end caps were machined from the bar sample and provided to another work package for the ATF-1 irradiation campaign in the milestone M3FT-14OR0202251.

  16. CO2ReMoVe | Open Energy Information

    Open Energy Info (EERE)

    of industrial, research and service organizations with experience in CO2 geological storage. References: CO2ReMoVe1 This article is a stub. You can help OpenEI by expanding...

  17. Co-Mo Electric Cooperative- Energy Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    Co-Mo Electric Cooperative provides rebates to its residential and commercial members who install air source, dual fuel, and/or geothermal heat pumps, and certain energy efficient appliances. Heat...

  18. Support effects on hydrotreating activity of NiMo catalysts

    SciTech Connect (OSTI)

    Dominguez-Crespo, M.A. Arce-Estrada, E.M.; Torres-Huerta, A.M.

    2007-10-15

    The effect of the gamma alumina particle size on the catalytic activity of NiMoS{sub x} catalysts prepared by precipitation method of aluminum acetate at pH = 10 was studied. The structural characterization of the supports was measured by using XRD, pyridine FTIR-TPD and nitrogen physisorption. NiMo catalysts were characterized during the preparation steps (annealing and sulfidation) using transmission electron microscopy (TEM). Hydrogen TPR studies of the NiMo catalysts were also carried out in order to correlate their hydrogenating properties and their catalytic functionality. Catalytic tests were carried out in a pilot plant at 613, 633 and 653 K temperatures. The results showed that the rate constants of hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatizing (HDA) at 613-653 K decreased in the following order: A > B > C corresponding to the increase of NiMoS particle size associated to these catalysts.

  19. M.O. Wascko, LSU NuInt05...

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

    O. Wascko, LSU NuInt05 26 September, 2005 MiniBooNE CC + CCQE Ratio M.O. Wascko, LSU J.R. Monroe, Columbia CC interactions Quasi-Elastic (CCQE) Inclusive Single +...

  20. Structural Insights into FeMo Cofactor Biosynthesis

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

    a catalytic component and a specific reductase, which, in the standard system, are referred to as the MoFe protein and the Fe protein. At the active site of the...

  1. Ethanol Conversion on Cyclic (MO3)3 (M = Mo, W) Clusters

    SciTech Connect (OSTI)

    Li, Zhenjun; Fang, Zongtang; Kelley, Matthew S.; Kay, Bruce D.; Rousseau, Roger J.; Dohnalek, Zdenek; Dixon, David A.

    2014-03-06

    Oxides of molybdenum and tungsten are an important class of catalytic materials with applications ranging from isomerization of alkanes and alkenes, partial oxidation of alcohols, selective reduction of nitric oxide and metathesis of alkeness.[1-10] While many studies have focused on the structure - function relationships, the nature of high catalytic activity is still being extensively investigated. There is a general agreement that the activity of supported MOx (M = W, Mo) catalysts is correlated with the presence of acidic sites, where the catalytic activity is strongly affected by the type of oxide support, delocalization of electron density, structures of tungsten oxide domains and presence of protons

  2. Cr-doped scandium borate laser

    DOE Patents [OSTI]

    Chai, Bruce H.; Lai, Shui T.; Long, Margaret N.

    1989-01-01

    A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

  3. Microstructures in rapidly solidified Ni-Mo alloys

    SciTech Connect (OSTI)

    Jayaraman, N.; Tewari, S.N.; Hemker, K.J.; Glasgow, T.K.

    1985-01-01

    Ni-Mo alloys of compositions ranging from pure Ni to Ni-40 at % Mo were rapidly solidified by chill block melt spinning in vacuum and were examined by optical metallography, x-ray diffraction and transmission electron microscopy. Rapid solidification resulted in an extension of molybdenum solubility in nickel from 28 to 37.5 at %. A number of different phases and microstructures were seen at different depths (solidification conditions) from the quenched surface of the melt spun ribbons.

  4. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    SciTech Connect (OSTI)

    Tanaka, Koichi; Anders, André

    2015-11-15

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements.

  5. Coated U(Mo) Fuel: As-Fabricated Microstructures

    SciTech Connect (OSTI)

    Emmanuel Perez; Dennis D. Keiser, Jr.; Ann Leenaers; Sven Van den Berghe; Tom Wiencek

    2014-04-01

    As part of the development of low-enriched uranium fuels, fuel plates have recently been tested in the BR-2 reactor as part of the SELENIUM experiment. These fuel plates contained fuel particles with either Si or ZrN thin film coating (up to 1 µm thickness) around the U-7Mo fuel particles. In order to best understand irradiation performance, it is important to determine the starting microstructure that can be observed in as-fabricated fuel plates. To this end, detailed microstructural characterization was performed on ZrN and Si-coated U-7Mo powder in samples taken from AA6061-clad fuel plates fabricated at 500°C. Of interest was the condition of the thin film coatings after fabrication at a relatively high temperature. Both scanning electron microscopy and transmission electron microscopy were employed. The ZrN thin film coating was observed to consist of columns comprised of very fine ZrN grains. Relatively large amounts of porosity could be found in some areas of the thin film, along with an enrichment of oxygen around each of the the ZrN columns. In the case of the pure Si thin film coating sample, a (U,Mo,Al,Si) interaction layer was observed around the U-7Mo particles. Apparently, the Si reacted with the U-7Mo and Al matrix during fuel plate fabrication at 500°C to form this layer. The microstructure of the formed layer is very similar to those that form in U-7Mo versus Al-Si alloy diffusion couples annealed at higher temperatures and as-fabricated U-7Mo dispersion fuel plates with Al-Si alloy matrix fabricated at 500°C.

  6. Cr segregation at the FeCr surface and the origin of corrosion resistance in ferritic steels

    SciTech Connect (OSTI)

    De Caro, M S; Morse, B; Egiebor, N; Farmer, J; Caro, A

    2008-11-22

    Structural materials in Gen-IV nuclear reactors will face severe conditions of high operating temperatures, high neutron flux exposure, and corrosive environment. Radiation effects and corrosion and chemical compatibility issues are factors that will limit the materials lifetime. Low-chromium (9-12 Cr wt.%) ferritic martensitic (F/M) steels are being considered as possible candidates because they offer good swelling resistance and good mechanical properties under extreme conditions of radiation dose and irradiation temperature. The surface chemistry of FeCr alloys, responsible for the corrosion properties, is complex. It exists today a controversy between equilibrium thermodynamic calculations, which suggest Cr depletion at the surface driven by the higher surface energy of Cr, and experimental data which suggest the oxidation process occurs in two stages, first forming a Fe-rich oxide, followed by a duplex oxide layer, and ending with a Cr-rich oxide. Moreover, it has been shown experimentally that corrosion resistance of F/M steels depends significantly on Cr content, increasing with increasing Cr content and with a threshold around 10% Cr, below which, the alloy behaves as pure Fe. In an attempt to rationalize these two contradicting observations and to understand the physical mechanism behind corrosion resistance in these materials we perform atomistic simulations using our FeCr empirical potential and analyze Cr equilibrium distributions at different compositions and temperatures in single and polycrystalline samples. We analyze the controversy in terms of thermodynamic and kinetic considerations.

  7. Development of Surface Complexation Models of Cr(VI) Adsorption...

    Office of Scientific and Technical Information (OSTI)

    Cr(VI) Adsorption on Soils, Sediments and Model Mixtures of Kaolinite, Montmorillonite, ... into aquifers and shallow sediments and soils via many anthropogenic activities. ...

  8. SF6432-CR (02-01-13) Cost Reimbursement

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

    a Government site to perform work shall have Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy & Quality Dept Release...

  9. SF6432-CR (02-01-13) Cost Reimbursement

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

    labor are authorized as direct charges Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy Department Release Date: 11...

  10. SF6432-CR (02-01-12) Cost Reimbursement

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

    as direct charges to this contract Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy & Quality Dept Release Date:...

  11. SF6432-CR (02-01-13) Cost Reimbursement

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

    by Part 931 of the DEAR by a Sandia audit. Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy Department Release Date: 04...

  12. SF6432-CR (02-01-13) Cost Reimbursement

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

    ... prior to any attempts to enter a government site as shown ... premises are subject to search. (e) Contractor shall ... SF 6432-CR Title: Standard Terms & Conditions for Cost ...

  13. SF6432-CR (02-01-12) Cost Reimbursement

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

    ... prior to any attempts to enter a government site as shown ... premises are subject to search. (e) Contractor will ... SF 6432-CR Title: Standard Terms & Conditions for Cost ...

  14. Ligand Bridging-Angle-Driven Assembly of Molecular Architectures Based on Quadruply Bonded Mo-Mo Dimers

    SciTech Connect (OSTI)

    Li, Jian-Rong; Yakovenko, Andrey A; Lu, Weigang; Timmons, Daren J; Zhuang, Wenjuan; Yuan, Daqiang; Zhou, Hong-Cai

    2010-12-15

    A systematic exploration of the assembly of Mo?(O?C-)?-based metalorganic molecular architectures structurally controlled by the bridging angles of rigid organic linkers has been performed. Twelve bridging dicarboxylate ligands were designed to be of different sizes with bridging angles of 0, 60, 90, and 120 while incorporating a variety of nonbridging functional groups, and these ligands were used as linkers. These dicarboxylate linkers assemble with quadruply bonded MoMo clusters acting as nodes to give 13 molecular architectures, termed metalorganic polygons/polyhedra with metal cluster node arrangements of a linear shape, triangle, octahedron, and cuboctahedron/anti-cuboctahedron. The syntheses of these complexes have been optimized and their structures determined by single-crystal X-ray diffraction. The results have shown that the shape and size of the resulting molecular architecture can be controlled by tuning the bridging angle and size of the linker, respectively. Functionalization of the linker can adjust the solubility of the ensuing molecular assembly but has little or no effect on the geometry of the product. Preliminary gas adsorption, spectroscopic, and electrochemical properties of selected members were also studied. The present work is trying to enrich metal-containing supramolecular chemistry through the inclusion of well-characterized quadruply bonded MoMo units into the structures, which can widen the prospect of additional electronic functionality, thereby leading to novel properties.

  15. Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

    SciTech Connect (OSTI)

    Niu, C.; Zaddach, A. J.; Oni, A. A.; Sang, X.; LeBeau, J. M.; Koch, C. C.; Irving, D. L.; Hurt, J. W.

    2015-04-20

    Spin-driven ordering of Cr in an equiatomic fcc NiFeCrCo high entropy alloy (HEA) was predicted by first-principles calculations. Ordering of Cr is driven by the reduction in energy realized by surrounding anti-ferromagnetic Cr with ferromagnetic Ni, Fe, and Co in an alloyed L1{sub 2} structure. The fully Cr-ordered alloyed L1{sub 2} phase was predicted to have a magnetic moment that is 36% of that for the magnetically frustrated random solid solution. Three samples were synthesized by milling or casting/annealing. The cast/annealed sample was found to have a low temperature magnetic moment that is 44% of the moment in the milled sample, which is consistent with theoretical predictions for ordering. Scanning transmission electron microscopy measurements were performed and the presence of ordered nano-domains in cast/annealed samples throughout the equiatomic NiFeCrCo HEA was identified.

  16. U-Mo Plate Blister Anneal Interim Report

    SciTech Connect (OSTI)

    Francine J. Rice; Daniel M. Wachs; Adam B. Robinson; Dennis D. Keiser Jr.; Jan-Fong Jue; Danielle M. Perez; Ross Finlay

    2010-10-01

    Blister thresholds in fuel elements have been a longstanding performance parameter for fuel elements of all types. This behavior has yet to be fully defined for the RERTR U-Mo fuel types. Blister anneal studies that began in 2007 have been expanded to include plates from more recent RERTR experiments. Preliminary data presented in this report encompasses the early generations of the U-Mo fuel systems and the most recent but still developing fuel system. Included is an overview of relevant dispersion fuel systems for the purposes of comparison.

  17. T-594: IBM solidDB Password Hash Authentication Bypass Vulnerability

    Broader source: Energy.gov [DOE]

    This vulnerability could allow remote attackers to execute arbitrary code on vulnerable installations of IBM solidDB. Authentication is not required to exploit this vulnerability.

  18. Policy Flash 2013-71 AL 2013-11 NON M&O CONTRACTOR BUSINESS SYSTEMS...

    Energy Savers [EERE]

    Policy Flash 2013-71 AL 2013-11 NON M&O CONTRACTOR BUSINESS SYSTEMS CLAUSES FOR SECTION H Policy Flash 2013-71 AL 2013-11 NON M&O CONTRACTOR BUSINESS SYSTEMS CLAUSES FOR SECTION H...

  19. Corrosion report for the U-Mo fuel concept

    SciTech Connect (OSTI)

    Henager, Jr., Charles H.; Bennett, Wendy D.; Doherty, Ann L.; Fuller, E. S.; Hardy, John S.; Omberg, Ronald P.

    2014-08-28

    The Fuel Cycle Research and Development (FCRD) program of the Office of Nuclear Energy (NE) has implemented a program to develop a Uranium-Molybdenum (U-Mo) metal fuel for Light Water Reactors (LWR)s. Uranium-Molybdenum fuel has the potential to provide superior performance based on its thermo-physical properties, which includes high thermal conductivity for less stored heat energy. With sufficient development, it may be able to provide the Light Water industry with a melt-resistant accident tolerant fuel with improved safety response. However, the corrosion of this fuel in reactor water environments needs to be further explored and optimized by additional alloying. The Pacific Northwest National Laboratory has been tasked with performing ex-reactor corrosion testing to characterize the performance of U-Mo fuel. This report documents the results of the effort to characterize and develop the U-Mo metal fuel concept for LWRs with regard to corrosion testing. The results of a simple screening test in buffered water at 30°C using surface alloyed U-10Mo is documented and discussed. The screening test was used to guide the selection of several potential alloy improvements that were found and are recommended for further testing in autoclaves to simulate PWR water conditions more closely.

  20. Magnetic properties and hyperfine interactions in Cr8, Cr7Cd, and Cr7Ni molecular rings from 19F-NMR

    SciTech Connect (OSTI)

    Bordonali, L; Garlatti, E; Casadei, C M; Furukawa, Y; Lascialfari, A; Carretta, S; Troiani, F; Timco, G; Winpenny, R E; Borsa, F

    2014-04-14

    A detailed experimental investigation of the 19F nuclear magnetic resonance is made on single crystals of the homometallic Cr8 antiferromagnetic molecular ring and heterometallic Cr7Cd and Cr7 Ni rings in the low temperature ground state. Since the F? ion is located midway between neighboring magnetic metal ions in the ring, the 19F-NMR spectra yield information about the local electronic spin density and 19F hyperfine interactions. In Cr8, where the ground state is a singlet with total spin S T = 0, the 19F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the 19F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state S T = 1. In the heterometallic rings, Cr7Cd and Cr7 Ni, whose ground state is magnetic with S T = 3/2 and S T = 1/2, respectively, the 19F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the 19F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F?-Ni2+ and the F?-Cd2+ bonds. The values of the hyperfine constants compare well to the ones known for F?-Ni2+ in KNiF3 and NiF2 and for F?-Cr3+ in K2NaCrF6. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F? ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  1. Tuning magnetism of monolayer MoS{sub 2} by doping vacancy and applying strain

    SciTech Connect (OSTI)

    Zheng, Huiling; Yang, Baishun; Han, Ruilin; Du, Xiaobo; Yan, Yu; Wang, Dingdi

    2014-03-31

    In view of important role of inducing and manipulating the magnetism in two-dimensional materials for the development of low-dimensional spintronic devices, the influences of strain on electronic structure and magnetic properties of commonly observed vacancies doped monolayer MoS{sub 2} are investigated using first-principles calculations. It is shown that unstrained V{sub S}, V{sub S2}, and V{sub MoS3} doped monolayer MoS{sub 2} systems are nonmagnetic, while the ground state of unstrained V{sub MoS6} doped system is magnetic and the magnetic moment is contributed mainly by six Mo atoms around V{sub MoS6}. In particular, tensile strain can induce magnetic moments in V{sub S}, V{sub S2}, and V{sub MoS3} doped monolayer MoS{sub 2} due to the breaking of Mo–Mo metallic bonds around the vacancies, while the magnetization induced by V{sub MoS6} can be effectively manipulated by equibiaxial strain due to the change of Mo–Mo metallic bonds around V{sub MoS6} under strains.

  2. Defects Engineered Monolayer MoS2 for Improved Hydrogen Evolution Reaction

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

    Ye, Gonglan; Gong, Yongji; Lin, Junhao; Li, Bo; He, Yongmin; Pantelides, Sokrates T.; Zhou, Wu; Vajtai, Robert; Ajayan, Pulickel M.

    2016-01-13

    MoS2 is a promising, low-cost material for electrochemical hydrogen production due to its high activity and stability during the reaction. Our work represents an easy method to increase the hydrogen production in electrochemical reaction of MoS2 via defect engineering, and helps to understand the catalytic properties of MoS2.

  3. Characterization of Cr-rich Cr-Sb multilayer films: Syntheses of a new metastable phase using modulated elemental reactants

    SciTech Connect (OSTI)

    Regus, Matthias; Mankovsky, Sergiy; Polesya, Svitlana; Kuhn, Gerhard; Ditto, Jeffrey; Schürmann, Ulrich; Jacquot, Alexandre; Bartholomé, Kilian; Näther, Christian; Winkler, Markus; König, Jan D.; Böttner, Harald; Kienle, Lorenz; Johnson, David C.; Ebert, Hubert; Bensch, Wolfgang

    2015-10-15

    The new metastable compound Cr{sub 1+x}Sb with x up to 0.6 has been prepared via a thin film approach using modulated elemental reactants and investigated by in-situ X-ray reflectivity, X-ray diffraction, differential scanning calorimetry, energy dispersive X-ray analysis as well as transmission electron microscopy and atomic force microscopy. The new Cr-rich antimonide crystallizes in a structure related to the Ni{sub 2}In-type structure, where the crystallographic position (1/3, 2/3, 3/4) is partially occupied by excess Cr. The elemental layers of the pristine material interdiffused significantly before Cr{sub 1+x}Sb crystallized. A change in the activation energy was observed for the diffusion process when crystal growth starts. First-principles electronic structure calculations provide insight into the structural stability, magnetic properties and resistivity of Cr{sub 1+x}Sb. - Graphical abstract: 1 amorphous multilayered film 2 interdiffused amorphous film 3 metastable crystalline phase 4 thermodynamic stable phase (and by-product). - Highlights: • Interdiffusion of amorphous Cr and Sb occurs before crystallization. • Crystallization of a new metastable phase Cr{sub 1.6}Sb in Ni{sub 2}In-type structure. • The new Cr-rich phase shows half-metallic behavior.

  4. 244-CR Vault Interim Stabilization Project Plan

    SciTech Connect (OSTI)

    PARKMAN, D.B.

    2000-04-25

    The 244-CR Vault is a two-level, multi-cell structure of reinforced concrete constructed below grade. The lower cell contains four individual compartments, each containing a steel process storage tank and equipped with a concrete sump. The upper cell contains the piping and support equipment, and has two compartments for each of the tanks. The ''pump pit'' is accessed by the removal of concrete cover blocks, while the smaller ''riser pit'' is accessed by steel cover plates. The facility most recently was used as a double-contained receiver tank (DCRT). A DCRT is a type of waste transfer tank that together with its related equipment constitutes a short-term storage area for liquid waste and has a pump pit for waste transfer operations. This vault most recently was used for short-term storage and waste routing for saltwell liquid pumped from the 241-C Tank Farm in the 200 East Area. Waste transfer lines are connected inside the pump pit by a jumper installed between connecting nozzles. An active ventilation system is in operation at the 244-CR vault. Ventilation supply air enters the upper vault section through an inlet header with some leakage through the spaces between the cell cover blocks. The upper and lower vaults are connected by exhauster ports, which allow airflow between the two sections. Normal flow moves air from the upper cell to the lower cell where it is removed and routed into a filter plenum; there the air is treated by a bank of four prefilters and two banks of high-efficiency particulate air (HEPA) filters (each containing four HEPAs). The air is exhausted to the atmosphere through the 296-C-05 Stack. The stack is equipped with a record sampler and continuous air monitor. Two fans (each rated at 4,200 cubic feet per minute) installed downstream of the filtration system provide the motive force for exhausting the vaults and the tanks. As an active system, it is operated continuously with only one of the two fans required to operate at a time. A continuous beta-gamma air monitor is interlocked to the operating fan. Loss of power to the fans will activate an alarm at the 244-AR facility.

  5. Structure and electronic properties of Cu nanoclusters supported on Mo2C(001) and MoC(001) surfaces

    SciTech Connect (OSTI)

    Posada-Pérez, Sergio; Viñes, Francesc; Rodríguez, José A.; Illas, Francesc

    2015-09-15

    In this study, the atomic structure and electronic properties of Cun nanoclusters (n = 4, 6, 7, and 10) supported on cubic nonpolar δ-MoC(001) and orthorhombic C- or Mo-terminated polar β-Mo2C(001) surfaces have been investigated by means of periodic density functional theory based calculations. The electronic properties have been analyzed by means of the density of states, Bader charges, and electron localization function plots. The Cu nanoparticles supported on β-Mo2C(001), either Mo- or C-terminated, tend to present a two-dimensional structure whereas a three-dimensional geometry is preferred when supported on δ-MoC(001), indicating that the Mo:C ratio and the surface polarity play a key role determining the structure of supported clusters. Nevertheless, calculations also reveal important differences between the C- and Mo-terminated β-Mo2C(001) supports to the point that supported Cu particles exhibit different charge states, which opens a way to control the reactivity of these potential catalysts.

  6. Interlayer coupling in Fe/Cr/Gd multilayer structures

    SciTech Connect (OSTI)

    Drovosekov, A. B. Kreines, N. M.; Savitsky, A. O.; Kravtsov, E. A.; Blagodatkov, D. V.; Ryabukhina, M. V.; Milyaev, M. A.; Ustinov, V. V.; Pashaev, E. M.; Subbotin, I. A.; Prutskov, G. V.

    2015-06-15

    The effect of the chromium layer thickness on the magnetic state of an [Fe/Cr/Gd/Cr]{sub n} multilayer structure is studied. A series of Fe/Cr/Gd structures with Cr spacer thicknesses of 4–30 Å is studied by SQUID magnetometry and ferromagnetic resonance in the temperature range 4.2–300 K. The obtained experimental results are described in terms of an effective field model, which takes into account a biquadratic contribution to the interlayer coupling energy and a nonuniform magnetization distribution inside the gadolinium layer (which was detected earlier). Depending on the magnetic field and temperature, the following types of magnetic ordering are identified at various chromium layer thicknesses: ferromagnetic, antiferromagnetic, and canted ordering. A comparison of the experimental and calculated curves allowed us to determine the dependence of the bilinear (J{sub 1}) and biquadratic (J{sub 2}) exchange constants on chromium layer thickness t{sub Cr}. Weak oscillations at a period of about 18 Å are detected in the J{sub 1}(t{sub Cr}) dependence in the range 8–30 Å. The interlayer coupling oscillations in the system under study are assumed to be related to the RKKY exchange interaction mechanism via the conduction electrons of Cr.

  7. Thermal transport properties of metal/MoS{sub 2} interfaces from first principles

    SciTech Connect (OSTI)

    Mao, Rui; Kong, Byoung Don; Kim, Ki Wook, E-mail: kwk@ncsu.edu [Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695-7911 (United States)

    2014-07-21

    Thermal transport properties at the metal/MoS{sub 2} interfaces are analyzed by using an atomistic phonon transport model based on the Landauer formalism and first-principles calculations. The considered structures include chemisorbed Sc(0001)/MoS{sub 2} and Ru(0001)/MoS{sub 2}, physisorbed Au(111)/MoS{sub 2}, as well as Pd(111)/MoS{sub 2} with intermediate characteristics. Calculated results illustrate a distinctive dependence of thermal transfer on the details of interfacial microstructures. More specifically, the chemisorbed case with a stronger bonding exhibits a generally smaller interfacial thermal resistance than the physisorbed. Comparison between metal/MoS{sub 2} and metal/graphene systems suggests that metal/MoS{sub 2} is significantly more resistive. Further examination of lattice dynamics identifies the presence of multiple distinct atomic planes and bonding patterns at the interface as the key origins of the observed large thermal resistance.

  8. Effects of Cr and Ni on Interdiffusion and Reaction between U and Fe-Cr-Ni Alloys

    SciTech Connect (OSTI)

    K. Huang; Y. Park; L. Zhou; K.R. Coffey; Y.H. Sohn; B.H. Sencer; J. R. Kennedy

    2014-08-01

    Metallic U-alloy fuel cladded in steel has been examined for high temperature fast reactor technology wherein the fuel cladding chemical interaction is a challenge that requires a fundamental and quantitative understanding. In order to study the fundamental diffusional interactions between U with Fe and the alloying effect of Cr and Ni, solid-to-solid diffusion couples were assembled between pure U and Fe, Fe–15 wt.%Cr or Fe–15 wt.%Cr–15 wt.%Ni alloy, and annealed at high temperature ranging from 580 to 700 °C. The microstructures and concentration profiles that developed from the diffusion anneal were examined by scanning electron microscopy, and X-ray energy dispersive spectroscopy (XEDS), respectively. Thick U6Fe and thin UFe2 phases were observed to develop with solubilities: up to 2.5 at.% Ni in U6(Fe,Ni), up to 20 at.%Cr in U(Fe, Cr)2, and up to 7 at.%Cr and 14 at.% Ni in U(Fe, Cr, Ni)2. The interdiffusion and reactions in the U vs. Fe and U vs. Fe–Cr–Ni exhibited a similar temperature dependence, while the U vs. Fe–Cr diffusion couples, without the presence of Ni, yielded greater activation energy for the growth of intermetallic phases – lower growth rate at lower temperature but higher growth rate at higher temperature.

  9. Development of uranium metal targets for {sup 99}Mo production

    SciTech Connect (OSTI)

    Wiencek, T.C.; Hofman, G.L.

    1993-10-01

    A substantial amount of high enriched uranium (HEU) is used for the production of medical-grade {sup 99}Mo. Promising methods of producing irradiation targets are being developed and may lead to the reduction or elimination of this HEU use. To substitute low enriched uranium (LEU) for HEU in the production of {sup 99}Mo, the target material may be changed to uranium metal foil. Methods of fabrication are being developed to simplify assembly and disassembly of the targets. Removal of the uranium foil after irradiation without dissolution of the cladding is a primary goal in order to reduce the amount of liquid radioactive waste material produced in the process. Proof-of-concept targets have been fabricated. Destructive testing indicates that acceptable contact between the uranium foil and the cladding can be achieved. Thermal annealing tests, which simulate the cladding/uranium diffusion conditions during irradiation, are underway. Plans are being made to irradiate test targets.

  10. Undercooled and rapidly quenched Ni-Mo alloys

    SciTech Connect (OSTI)

    Tewari, S.N.; Glasgow, T.K.

    1986-01-01

    Hypoeutectic, eutectic, and hypereutectic nickel-molybdenum alloys were rapidly solidified by both bulk undercooling and melt spinning techniques. Alloys were undercooled in both electromagnetic levitation and differential thermal analysis equipment. The rate of recalescence depended upon the degree of initial undercooling and the nature (faceted or nonfaceted) of the primary nucleating phase. Alloy melts were observed to undercool more in the presence of primary Beta (NiMo intermetallic) phase than in gamma (fcc solid solution) phase. Melt spinning resulted in an extension of molybdenum solid solubility in gamma nickel, from 28 to 37.5 at % Mo. Although the microstructures observed by undercooling and melt spinning were similar the microsegregation pattern across the gamma dendries was different. The range of microstructures evolved was analyzed in terms of the nature of the primary phase to nucleate, its subsequent dendritic growth, coarsening and fragmentation, and final solidification of interfenderitic liquid.

  11. IRRADIATION PERFORMANCE OF U-Mo MONOLITHIC FUEL

    SciTech Connect (OSTI)

    M.K. Meyer; J. Gan; J.-F. Jue; D.D. Keiser; E. Perez; A. Robinson; D.M. Wachs; N. Woolstenhulme; G.L. Hofman; Y.-S. Kim

    2014-04-01

    High-performance research reactors require fuel that operates at high specific power to high fission density, but at relatively low temperatures. Research reactor fuels are designed for efficient heat rejection, and are composed of assemblies of thin-plates clad in aluminum alloy. The development of low-enriched fuels to replace high-enriched fuels for these reactors requires a substantially increased uranium density in the fuel to offset the decrease in enrichment. Very few fuel phases have been identified that have the required combination of very-high uranium density and stable fuel behavior at high burnup. UMo alloys represent the best known tradeoff in these properties. Testing of aluminum matrix U-Mo aluminum matrix dispersion fuel revealed a pattern of breakaway swelling behavior at intermediate burnup, related to the formation of a molybdenum stabilized high aluminum intermetallic phase that forms during irradiation. In the case of monolithic fuel, this issue was addressed by eliminating, as much as possible, the interfacial area between U-Mo and aluminum. Based on scoping irradiation test data, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development. Developmental testing of this fuel system indicates that it meets core criteria for fuel qualification, including stable and predictable swelling behavior, mechanical integrity to high burnup, and geometric stability. In addition, the fuel exhibits robust behavior during power-cooling mismatch events under irradiation at high power.

  12. TI--CR--AL--O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  13. Phase stability and elastic properties of Cr-V alloys

    SciTech Connect (OSTI)

    Gao, M. C.; Suzuki, Y.; Schweiger, H.; Do?an, .N.; Hawk, J.; Widom M.

    2013-02-20

    V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and elastic properties of CrV binary alloys. The cluster expansion study reveals the formation of various ordered compounds at low temperatures that were not previously known. These compounds become unstable due to the configurational entropy of bcc solid solution as the temperature is increased. The elastic constants of ordered and disordered compounds are calculated at both T = 0 K and finite temperatures. The overall trends in elastic properties are in agreement with measurements using the resonant ultrasound spectroscopy method. The calculations predict that addition of V to Cr decreases both the bulk modulus and the shear modulus, and enhances the Poissons ratio, in agreement with experiments. Decrease in the bulk modulus is correlated to decrease in the valence electron density and increase in the lattice constant. An enhanced Poissons ratio for bcc CrV alloys (compared to pure Cr) is associated with an increased density of states at the Fermi level. Furthermore, the difference charge density in the bonding region in the (110) slip plane is highest for pure Cr and decreases gradually as V is added. The present calculation also predicts a negative Cauchy pressure for pure Cr, and it becomes positive upon alloying with V. The intrinsic ductilizing effect from V may contribute, at least partially, to the experimentally observed ductilizing phenomenon in the literature.

  14. SF6432-CR (02-01-13) Cost Reimbursement

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

    CR xx-xxxx) Initial release SANDIA CORPORATION SF 6432-CR (04/2015) SECTION II STANDARD TERMS AND CONDITIONS FOR COST-REIMBURSEMENT CONTRACTS THE FOLLOWING CLAUSES APPLY TO THIS CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY IDENTIFIED AS BEING CHANGED, SUPPLEMENTED, OR AMENDED IN WRITING ISSUED BY THE SANDIA CONTRACTING REPRESENTATIVE. (CTRL+CLICK ON A LINK BELOW TO ADVANCE DIRECTLY TO THAT SECTION) ACCEPTANCE OF TERMS AND CONDITIONS (Ts&Cs)

  15. Single Phase Melt Processed Powellite (Ba,Ca) MoO{sub 4} For The Immobilization Of Mo-Rich Nuclear Waste

    SciTech Connect (OSTI)

    Brinkman, Kyle; Marra, James; Fox, Kevin; Reppert, Jason; Crum, Jarrod; Tang, Ming

    2012-09-17

    Crystalline and glass composite materials are currently being investigated for the immobilization of combined High Level Waste (HLW) streams resulting from potential commercial fuel reprocessing scenarios. Several of these potential waste streams contain elevated levels of transition metal elements such as molybdenum (Mo). Molybdenum has limited solubility in typical silicate glasses used for nuclear waste immobilization. Under certain chemical and controlled cooling conditions, a powellite (Ba,Ca)MoO{sub 4} crystalline structure can be formed by reaction with alkaline earth elements. In this study, single phase BaMoO{sub 4} and CaMoO{sub 4} were formed from carbonate and oxide precursors demonstrating the viability of Mo incorporation into glass, crystalline or glass composite materials by a melt and crystallization process. X-ray diffraction, photoluminescence, and Raman spectroscopy indicated a long range ordered crystalline structure. In-situ electron irradiation studies indicated that both CaMoO{sub 4} and BaMoO{sub 4} powellite phases exhibit radiation stability up to 1000 years at anticipated doses with a crystalline to amorphous transition observed after 1 X 10{sup 13} Gy. Aqueous durability determined from product consistency tests (PCT) showed low normalized release rates for Ba, Ca, and Mo (<0.05 g/m{sup 2}).

  16. Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys

    SciTech Connect (OSTI)

    Chiriac, H.; Whitmore, L.; Grigoras, M.; Ababei, G.; Stoian, G.; Lupu, N.

    2015-05-07

    High resolution imaging and electron diffraction confirm that in the as-quenched state the structure of Fe{sub 79.7−x}Cr{sub x}Nb{sub 0.3}B{sub 20} (x = 11–13 at. %) melt-spun ribbons is completely amorphous, independent of the Cr content. Energy-dispersive X-ray spectroscopy mapping emphasizes clearly the presence of Fe and Cr clusters varying from approximately 1 to 2–3 nm in size with the increase of Cr content from 11 to 13 at. %. The Fe and Cr atoms segregate the atomic scale to form nanometer sized clusters, influencing strongly the macroscopic magnetic behavior. The Curie temperature of the system, T{sub C}{sup system}, confirmed by the magnetic susceptibility versus temperature measurements, gives the strength of the magnetic interactions between clusters. The inter-cluster interactions are much stronger for lower contents of Cr, the microstructure is less uniform, and T{sub C}{sup system} increases from 290 K for 13 at. % Cr to 330 K for 11.5 at. % Cr. The whole system transforms to a ferromagnetic state through interactions between the clusters. Zero-field cooling and field cooling curves confirm the cluster behavior with a blocking temperature, T{sub b}, of about 250 K. Above T{sub b}, the ribbons behave as a superferromagnetic system, whilst below the blocking temperature a classical ferromagnetic behavior is observed.

  17. Bonding between graphene and MoS{sub 2} monolayers without and with Li

    Office of Scientific and Technical Information (OSTI)

    intercalation (Journal Article) | SciTech Connect Journal Article: Bonding between graphene and MoS{sub 2} monolayers without and with Li intercalation Citation Details In-Document Search Title: Bonding between graphene and MoS{sub 2} monolayers without and with Li intercalation We performed density functional theory (DFT) calculations for a bi-layered heterostructure combining a graphene layer with a MoS{sub 2} layer with and without intercalated Li atoms. Our calculations demonstrate the

  18. Chromium Isotope Fractionation During Reduction of Cr(VI) Under Saturated Flow Conditions

    SciTech Connect (OSTI)

    Jamieson-Hanes, Julia H.; Gibson, Blair D.; Lindsay, Matthew B.J.; Kim, Yeongkyoo; Ptacek, Carol J.; Blowes, David W.

    2012-10-25

    Chromium isotopes are potentially useful indicators of Cr(VI) reduction reactions in groundwater flow systems; however, the influence of transport on Cr isotope fractionation has not been fully examined. Laboratory batch and column experiments were conducted to evaluate isotopic fractionation of Cr during Cr(VI) reduction under both static and controlled flow conditions. Organic carbon was used to reduce Cr(VI) in simulated groundwater containing 20 mg L{sup -1} Cr(VI) in both batch and column experiments. Isotope measurements were performed on dissolved Cr on samples from the batch experiments, and on effluent and profile samples from the column experiment. Analysis of the residual solid-phase materials by scanning electron microscopy (SEM) and by X-ray absorption near edge structure (XANES) spectroscopy confirmed association of Cr(III) with organic carbon in the column solids. Decreases in dissolved Cr(VI) concentrations were coupled with increases in {delta}{sup 53}Cr, indicating that Cr isotope enrichment occurred during reduction of Cr(VI). The {delta}{sup 53}Cr data from the column experiment was fit by linear regression yielding a fractionation factor ({alpha}) of 0.9979, whereas the batch experiments exhibited Rayleigh-type isotope fractionation ({alpha} = 0.9965). The linear characteristic of the column {delta}{sup 53}Cr data may reflect the contribution of transport on Cr isotope fractionation.

  19. Surface structure of ?-Cr2O3(0001) after activated oxygen exposure

    SciTech Connect (OSTI)

    Kaspar, Tiffany C.; Chamberlin, Sara E.; Chambers, Scott A.

    2013-09-13

    The surface structure of a-Cr2O3(0001) before and after exposure to activated oxygen from an ECR plasma source was investigated by x-ray photoelectron spectroscopy (XPS) and x-ray photoelectron diffraction (XPD). Epitaxial Cr2O3(0001) thin films were deposited on Al2O3(0001) substrates by oxygen-plasma-assisted molecular beam epitaxy (OPA-MBE). When cooled or annealed in vacuum, strong evidence for a Cr-Cr-O3- termination was obtained by comparing the Cr3+ XPD azimuthal scan to single scattering simulations. However, after plasma exposure, a high binding energy feature was observed in the Cr 2p XPS spectrum that possesses an ordered structure distinct from the underlying Cr3+ of Cr2O3, which remains Cr-Cr-O3-like. Investigation of this new surface structure with simulations of various candidate structures tentatively rules out CrO2-like configurations. The high binding energy feature likely arises from a higher oxidation state of Cr. One possibility is the oxidation of the surface layer of Cr to Cr6- with a double chromyl structure (O=Cr=O).

  20. Recovery of Mo/Si multilayer coated optical substrates

    DOE Patents [OSTI]

    Baker, S.L.; Vernon, S.P.; Stearns, D.G.

    1997-12-16

    Mo/Si multilayers are removed from superpolished ZERODUR and fused silica substrates with a dry etching process that, under suitable processing conditions, produces negligible change in either the substrate surface figure or surface roughness. The two step dry etching process removes SiO{sub 2} overlayer with a fluroine-containing gas and then moves molybdenum and silicon multilayers with a chlorine-containing gas. Full recovery of the initial normal incidence extreme ultra-violet (EUV) reflectance response has been demonstrated on reprocessed substrates. 5 figs.

  1. Recovery of Mo/Si multilayer coated optical substrates

    DOE Patents [OSTI]

    Baker, Sherry L.; Vernon, Stephen P.; Stearns, Daniel G.

    1997-12-16

    Mo/Si multilayers are removed from superpolished ZERODUR and fused silica substrates with a dry etching process that, under suitable processing conditions, produces negligible change in either the substrate surface figure or surface roughness. The two step dry etching process removes SiO.sub.2 overlayer with a fluroine-containing gas and then moves molybdenum and silicon multilayers with a chlorine-containing gas. Full recovery of the initial normal incidence extreme ultra-violet (EUV) reflectance response has been demonstrated on reprocessed substrates.

  2. Greenfield Alternative Study LEU-Mo Fuel Fabrication Facility

    SciTech Connect (OSTI)

    Washington Division of URS

    2008-07-01

    This report provides the initial “first look” of the design of the Greenfield Alternative of the Fuel Fabrication Capability (FFC); a facility to be built at a Greenfield DOE National Laboratory site. The FFC is designed to fabricate LEU-Mo monolithic fuel for the 5 US High Performance Research Reactors (HPRRs). This report provides a pre-conceptual design of the site, facility, process and equipment systems of the FFC; along with a preliminary hazards evaluation, risk assessment as well as the ROM cost and schedule estimate.

  3. Gamma-ray decay of levels in /sup 53/Cr

    SciTech Connect (OSTI)

    Dickens, J.K.; Larson, D.C.

    1987-11-01

    Gamma-ray decay of levels in the stable isotope /sup 53/Cr has been studied using /sup 53/Cr(n,n'..gamma..) reactions for incident neutron energies between threshold and 10 MeV. Of the 65 gamma rays or gamma-ray groups observed for neutron interactions with /sup 53/Cr, 50 have been placed or tentatively placed among 34 levels in /sup 53/Cr up to an excitation energy of 4.36 MeV. Deduced branching ratios are in reasonable agreement with previous measurements except for decay of the E/sub x/ = 1537-keV level. For the decay of the E/sub x/ = 1537-keV level we are unable to explain variations in the branching ratios of the transition gamma rays as a function of incident neutron energy within the framework of the presently known level structure of /sup 53/Cr and suggest the possibility of a second energy level at E/sub x/ = 1537 keV. 59 refs., 13 figs., 2 tabs.

  4. Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy...

    Office of Scientific and Technical Information (OSTI)

    Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding Citation Details In-Document Search Title: Improving Accident Tolerance of Nuclear Fuel with Coated ...

  5. Experimental activities supporting commercial U.S. accelerator production of 99-Mo

    SciTech Connect (OSTI)

    Dale, Gregory E [Los Alamos National Laboratory; Chemerisov, Sergey D [ANL; Vandegrift, George F [ANL

    2010-01-01

    {sup 99m}Tc, the daughter product of {sup 99}Mo, is the most commonly used radioisotope for nuclear medicine in the U.S. Experiments are being performed at Los Alamos National Laboratory and Argonne National Laboratory to demonstrate production of {sup 99}Mo using accelerators. The {sup 100}Mo({gamma},n){sup 99}Mo reaction in an enriched {sup 100}Mo target is currently under investigation. Three scaled low-power production experiments using a 20-MeV electron linac at Argonne have been performed to date. Two of these experiments used natural Mo targets and produced a total of 613 {mu}C of {sup 99}Mo. The third experiment used an enriched {sup 100}Mo target and produced 10.5 mCi of {sup 99}Mo. Following irradiation the targets were dissolved and the low specific activity solution was processed through an ARSII generator from NorthStar Medical Radioisotopes. Yields of {sup 99m}Tc >95% have been observed.

  6. Conceptual design of a new homogeneous reactor for medical radioisotope Mo-99/Tc-99m production

    SciTech Connect (OSTI)

    Liem, Peng Hong [Nippon Advanced Information Service (NAIS Co., Inc.) Scientific Computational Division, 416 Muramatsu, Tokaimura, Ibaraki (Japan); Tran, Hoai Nam [Chalmers University of Technology, Dept. of Applied Physics, Div. of Nuclear Engineering, SE-412 96 Gothenburg (Sweden); Sembiring, Tagor Malem [National Nuclear Energy Agency (BATAN), Center for Reactor Technology and Nuclear Safety, Kawasan Puspiptek, Serpong, Tangerang Selatan, Banten (Indonesia); Arbie, Bakri [PT MOTAB Technology, Kedoya Elok Plaza Blok DA 12, Jl. Panjang, Kebun Jeruk, Jakarta Barat (Indonesia)

    2014-09-30

    To partly solve the global and regional shortages of Mo-99 supply, a conceptual design of a nitrate-fuel-solution based homogeneous reactor dedicated for Mo-99/Tc-99m medical radioisotope production is proposed. The modified LEU Cintichem process for Mo-99 extraction which has been licensed and demonstrated commercially for decades by BATAN is taken into account as a key design consideration. The design characteristics and main parameters are identified and the advantageous aspects are shown by comparing with the BATAN's existing Mo-99 supply chain which uses a heterogeneous reactor (RSG GAS multipurpose reactor)

  7. Acquisition Guide Chapter 7.3:Acquisition Planning in the M&O Environment

    Broader source: Energy.gov [DOE]

    Acquisition Letter 2013-03, Acquisition Planning Considerations for M&O Contracts, has been moved to the Acquisition Guide as chapter (7.3).

  8. Synthesis of molybdenum disulfide (MoS{sub 2}) for lithium ion battery applications

    SciTech Connect (OSTI)

    Feng Chuanqi; Ma Jun; Li Hua; Zeng Rong; Guo Zaiping; Liu Huakun

    2009-09-15

    This paper reports the use of a rheological phase reaction method for preparing MoS{sub 2} nanoflakes. The characterization by powder X-ray diffraction indicated that MoS{sub 2} had been formed. High resolution electron microscopy observation revealed that the as-prepared MoS{sub 2} nanoflakes had started to curve and partly form MoS{sub 2} nanotubes. The lithium intercalation/de-intercalation behavior of as-prepared MoS{sub 2} nanoflake electrode was also investigated. It was found that the MoS{sub 2} nanoflake electrode exhibited higher specific capacity, with very high cycling stability, compared to MoS{sub 2} nanoparticle electrode. The possible reasons for the high electrochemical performance of the nanoflakes electrodes are also discussed. The outstanding electrochemical properties of MoS{sub 2} nanoflakes obtained by this method make it possible for MoS{sub 2} to be used as a promising anode material.

  9. Solution-based thermodynamic modeling of the Ni-Al-Mo system using

    Office of Scientific and Technical Information (OSTI)

    first-principles calculations (Journal Article) | SciTech Connect Solution-based thermodynamic modeling of the Ni-Al-Mo system using first-principles calculations Citation Details In-Document Search Title: Solution-based thermodynamic modeling of the Ni-Al-Mo system using first-principles calculations A solution-based thermodynamic description of the ternary Ni-Al-Mo system is developed here, incorporating first-principles calculations and reported modeling of the binary Ni-Al, Ni-Mo and

  10. Domestic production of medical isotope Mo-99 moves a step closer

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

    partners, including Morgridge Institute for Research-SHINE Medical Technologies (MIR-SHINE), which proposes to use a particle accelerator to produce Mo-99 from a mildly...

  11. Mechanically Activated Combustion Synthesis of MoSi2-Based Composites

    SciTech Connect (OSTI)

    Shafirovich, Evgeny

    2015-09-30

    The thermal efficiency of gas-turbine power plants could be dramatically increased by the development of new structural materials based on molybdenum silicides and borosilicides, which can operate at temperatures higher than 1300 °C with no need for cooling. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at high temperatures. One approach is based on the fabrication of MoSi2-Mo5Si3 composites that combine high oxidation resistance of MoSi2 and good mechanical properties of Mo5Si3. Another approach involves the addition of boron to Mo-rich silicides for improving their oxidation resistance through the formation of a borosilicate surface layer. In particular, materials based on Mo5SiB2 phase are promising materials that offer favorable combinations of high temperature mechanical properties and oxidation resistance. However, the synthesis of Mo-Si-B multi-phase alloys is difficult because of their extremely high melting temperatures. Mechanical alloying has been considered as a promising method, but it requires long milling times, leading to large energy consumption and contamination of the product by grinding media. In the reported work, MoSi2-Mo5Si3 composites and several materials based on Mo5SiB2 phase have been obtained by mechanically activated self-propagating high-temperature synthesis (MASHS). Short-term milling of Mo/Si mixture in a planetary mill has enabled a self-sustained propagation of the combustion front over the mixture pellet, leading to the formation of MoSi2-T1 composites. Combustion of Mo/Si/B mixtures for the formation of T2 phase becomes possible if the composition is designed for the addition of more exothermic reactions leading to the formation of MoB, TiC, or TiB2. Upon ignition, Mo/Si/B and Mo/Si/B/Ti mixtures exhibited spin combustion, but the products were porous, contained undesired secondary phases, and had low oxidation resistance. It has been shown that use of SHS compaction (quasi-isostatic pressing after combustion) significantly improves oxidation resistance of the obtained MoSi2-Mo5Si3 composites. The “chemical oven” technique has been successfully employed to fabricate low-porous Mo5SiB2–TiC, Mo5SiB2–TiB2, and Mo–Mo5SiB2–Mo3Si materials. Among them, Mo5SiB2–TiB2 material possesses good mechanical properties and simultaneously exhibits excellent oxidation resistance at temperatures up to 1500 °C.

  12. Characterization of U-Mo Foils for AFIP-7

    SciTech Connect (OSTI)

    Edwards, Danny J.; Ermi, Ruby M.; Schemer-Kohrn, Alan L.; Overman, Nicole R.; Henager, Charles H.; Burkes, Douglas; Senor, David J.

    2012-11-07

    Twelve AFIP in-process foil samples, fabricated by either Y-12 or LANL, were shipped from LANL to PNNL for potential characterization using optical and scanning electron microscopy techniques. Of these twelve, nine different conditions were examined to one degree or another using both techniques. For this report a complete description of the results are provided for one archive foil from each source of material, and one unirradiated piece of a foil of each source that was irradiated in the Advanced Test Reactor. Additional data from two other LANL conditions are summarized in very brief form in an appendix. The characterization revealed that all four characterized conditions contained a cold worked microstructure to different degrees. The Y-12 foils exhibited a higher degree of cold working compared to the LANL foils, as evidenced by the highly elongated and obscure U-Mo grain structure present in each foil. The longitudinal orientations for both of the Y-12 foils possesses a highly laminar appearance with such a distorted grain structure that it was very difficult to even offer a range of grain sizes. The U-Mo grain structure of the LANL foils, by comparison, consisted of a more easily discernible grain structure with a mix of equiaxed and elongated grains. Both materials have an inhomogenous grain structure in that all of the characterized foils possess abnormally coarse grains.

  13. Room-temperature ferromagnetism in Cr-doped Si achieved by controlling atomic structure, Cr concentration, and carrier densities: A first-principles study

    SciTech Connect (OSTI)

    Wei, Xin-Yuan; Yang, Zhong-Qin; Zhu, Yan; Li, Yun

    2015-04-28

    By using first-principles calculations, we investigated how to achieve a strong ferromagnetism in Cr-doped Si by controlling the atomic structure and Cr concentration as well as carrier densities. We found that the configuration in which the Cr atom occupies the tetrahedral interstitial site can exist stably and the Cr atom has a large magnetic moment. Using this doping configuration, room-temperature ferromagnetism can be achieved in both n-type and p-type Si by tuning Cr concentration and carrier densities. The results indicate that the carrier density plays a crucial role in realizing strong ferromagnetism in diluted magnetic semiconductors.

  14. Grain boundary depletion and migration during selective oxidation of Cr in a Ni-5Cr binary alloy exposed to high-temperature hydrogenated water

    SciTech Connect (OSTI)

    Schreiber, Daniel K.; Olszta, Matthew J.; Bruemmer, Stephen M.

    2014-10-01

    High-resolution microscopy of a high-purity Ni-5Cr alloy exposed to 360C hydrogenated water reveals intergranular selective oxidation of Cr accompanied by local Cr depletion and diffusion-induced grain boundary migration (DIGM). The corrosion-product oxide consists of a porous, interconnected network of Cr2O3 platelets with no further O ingress into the metal ahead. Extensive grain boundary depletion of Cr (to <0.05at.%) is observed typically 20100 nm wide as a result of DIGM and reaching depths of many micrometers beyond the oxidation front.

  15. Importance of Doping and Frustration in Itinerant Fe-doped Cr2Al

    SciTech Connect (OSTI)

    Susner, Michael A; Parker, David S; Safa-Sefat, Athena

    2015-01-01

    We have performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x 0.125 after which point increasing paramagnetic behavior is exhibited. This is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculations explain that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.

  16. Importance of Doping and Frustration in Itinerant Fe-doped Cr2Al

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

    Susner, Michael A; Parker, David S; Safa-Sefat, Athena

    2015-01-01

    We have performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x 0.125 after which point increasing paramagnetic behavior is exhibited. This is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculationsmore » explain that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.« less

  17. Metastable bcc phase formation in the Nb-Cr system

    SciTech Connect (OSTI)

    Thoma, D.J.; Schwarz, R.B.; Perepezko, J.H.; Plantz, D.H.

    1993-08-01

    Extended metastable bcc solid solutions of Nb-Xat.%Cr (X = 35, 50, 57, 77, 82, and 94) were synthesized by two-anvil splat-quenching. In addition, bcc (Nb-67at.%Cr) was prepared by mechanically alloying mixtures of niobium and chromium powders. The lattice parameters were measured by X-ray diffraction and the Young`s moduli were measured by low-load microindentation. The composition dependence of the lattice parameters and elastic moduli show a positive deviation with respect to a rule of mixtures. During continuous heating at 15C/min., the metastable precursor bcc phases decomposed at temperatures above 750C to uniformly refined microstructures.

  18. New Generation of MoSx Based Solid Lubricant Coatings: Recent Developments and Applications

    SciTech Connect (OSTI)

    Haider, Julfikar; Hashmi, M. S. J.

    2011-01-17

    In recent times, there is a growing interest in applying Molybdenum disulphide (MoS{sub x}) solid lubricant coatings on components to improve the tribological performance (i.e. lower friction coefficient and wear rate). The tribological performance of MoS{sub x} coating is strongly dependent on coating properties and tribological environment. MoS{sub x} coatings are highly successful in certain applications such as in space/vacuum technology, but its effectiveness is questioned in other terrestrial applications such as in cutting tool industry due to its lower hardness and poor oxidation resistance leading to shorter life. In order to circumvent this drawback, the paper identifies that current research is being concentrated on developing MoS{sub x} based coatings using three different approaches: (1) Metal or compound addition in MoS{sub x} coating (2)MoS{sub x} layer on hard coating and (3)MoS{sub x} addition in hard coating matrix. Although the primary objective is same in all three cases, the third approach is considered to be more effective in improving the tribological properties of the coating. Finally, the potential applications of MoS{sub x} based coatings in different industrial sectors have been briefly outlined.

  19. Audit Report: CR-FS-99-01

    Energy Savers [EERE]

    MANAGEMENT REPORT AUDIT OF THE DEPARTMENT OF ENERGY'S CONSOLIDATED FINANCIAL STATEMENTS FOR FISCAL YEAR 1998 Report Number: CR-FS-99-01 Capital Regional Audit Office Date of Issue: June 15, 1999 Germantown, MD 20874 MANAGEMENT REPORT AUDIT OF THE DEPARTMENT OF ENERGY'S CONSOLIDATED FINANCIAL STATEMENTS FOR FISCAL YEAR 1998 TABLE OF CONTENTS Page SUMMARY.................................................................................. 1 PART I - APPROACH AND

  20. CR-39 track etching and blow-up method

    DOE Patents [OSTI]

    Hankins, Dale E. (Livermore, CA)

    1987-01-01

    This invention is a method of etching tracks in CR-39 foil to obtain uniformly sized tracks. The invention comprises a step of electrochemically etching the foil at a low frequency and a "blow-up" step of electrochemically etching the foil at a high frequency.

  1. Shell model description of band structure in 48Cr

    SciTech Connect (OSTI)

    Vargas, Carlos E.; Velazquez, Victor M.

    2007-02-12

    The band structure for normal and abnormal parity bands in 48Cr are described using the m-scheme shell model. In addition to full fp-shell, two particles in the 1d3/2 orbital are allowed in order to describe intruder states. The interaction includes fp-, sd- and mixed matrix elements.

  2. Magnetization reversal in TmCrO{sub 3}

    SciTech Connect (OSTI)

    Yoshii, Kenji

    2012-11-15

    Highlights: ► We observed two magnetization reversals in TmCrO{sub 3}. ► The reversal at 28 K is attributed to antiparallel coupling between Cr{sup 3+} and Tm{sup 3+}. ► The other reversal originates from spin reorientation. ► Magnetocaloric effect is observed at the spin reorientation temperature. ► Characteristic magnetization switching is demonstrated. -- Abstract: The perovskite chromite TmCrO{sub 3} shows magnetization reversal at two temperatures. The reversal at ∼28 K is attributed to the antiparallel coupling between Tm{sup 3+} and Cr{sup 3+} moments, while that at the lower temperature (∼6–7 K) is rooted in a rotation of the magnetic moments. Magnetocaloric measurements offer a relatively large entropy change (∼4–5 J kg{sup −1} K{sup −1}) at the lower temperature. The reversal at ∼28 K is accompanied by a sign change of an exchange-bias-like field. The absence of the training effect suggests that this behavior is rooted in unidirectional magnetic anisotropy. The existence of the two magnetization reversals offers the characteristic switching of magnetization. For example, the magnetization is flipped without changing the direction of the applied magnetic field.

  3. Photo-oxidation method using MoS2 nanocluster materials

    DOE Patents [OSTI]

    Wilcoxon, Jess P.

    2001-01-01

    A method of photo-oxidizing a hydrocarbon compound is provided by dispersing MoS.sub.2 nanoclusters in a solvent containing a hydrocarbon compound contaminant to form a stable solution mixture and irradiating the mixture to photo-oxide the hydrocarbon compound. Hydrocarbon compounds of interest include aromatic hydrocarbon and chlorinated hydrocarbons. MoS.sub.2 nanoclusters with an average diameter less than approximately 10 nanometers are shown to be effective in decomposing potentially toxic aromatic and chlorinated hydrocarbons, such as phenol, pentachlorophenol, chlorinated biphenols, and chloroform, into relatively non-toxic compounds. The irradiation can occur by exposing the MoS.sub.2 nanoclusters and hydrocarbon compound mixture with visible light. The MoS.sub.2 nanoclusters can be introduced to the toxic hydrocarbons as either a MoS.sub.2 solution or deposited on a support material.

  4. Synthesis and characterization of model MgO supported catalyst with Pt-Mo interactions.

    SciTech Connect (OSTI)

    Alexeev, O.; Kawi, S.; Gates, B.C. [Univ. of California, Davis, CA (United States)] [Univ. of California, Davis, CA (United States); Shelef, M. [Ford Motor Co., Dearborn, MI (United States)] [Ford Motor Co., Dearborn, MI (United States)

    1996-01-04

    MgO supported platinum and platinum-molybdenum catalysts were prepared from organometallic precursors and charaterized structurally to determine how the nature of the bimetallic precursors and the treatment conditions affected the interaction between the two metals. Samples were prepared from [PtCl{sub 2}(PhCN){sub 2}], [PtCl{sub 2}(PhCN){sub 2}] + [Mo(CO){sub 6}], and [C@Pt[Mo(CO){sub 3}(C{sub 5}H{sub 5})]{sub 2}(PhCN){sub 2}] BC@ characterized by infrared and extended X-ray absorption fine structure (EXAFS) spectroscopies, tranmission electron microscopy, and chemisorption of H{sub 2}, CO, and O{sub 2}. The samples were treated in H{sub 2} at 400{degree}C prior to most of the characterizatons. Incorporation of Mo reduced the chemisorption of CO and of H{sub 2}. EXAFS spectra measured at the Pt L{sub III} edge and at the Mo K edge showed substantial Pt-Mo contributions with a Pt-Mo cordination number of about 2 and an average distance of 2.63 A for the sample prepared from [C@Pt[Mo(CO){sub 3}(C{sub 5}H{sub 5})]{sub 2}(PhCN){sub 2}] BC@. In constract, no significant Pt-Mo contribution was observed for the sample prepared from [PtCl{sub 2}(PhCN){sub 2}]+ [Mo(CO){sub 6}]. Electron micrographs and EXAFS results show that interaction between Pt and Mo ions in the former sample helped to maintain the platinum in a highly dispersed form, with supported platinum clusters being smaller than about 10 A. 53 refs., 9 figs., 9 tabs.

  5. Pressure dependence of the magnetic order in CrAs: A neutron...

    Office of Scientific and Technical Information (OSTI)

    Pressure dependence of the magnetic order in CrAs: A neutron diffraction investigation Citation Details In-Document Search Title: Pressure dependence of the magnetic order in CrAs:...

  6. Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized...

    Office of Scientific and Technical Information (OSTI)

    Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter deposition Title: Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter ...

  7. The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via...

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

    labilization of the Fe(III)-O coordination bond in a mesoporous metal-organic framework, PCN-333-Fe(III), is realized by the reduction of Fe(III) by Cr(II). The Fe(II)-Cr(II)...

  8. Technology Implimentation Plan - ATF FeCrAl Cladding for LWR Application

    SciTech Connect (OSTI)

    Snead, Mary A.; Snead, Lance; Terrani, Kurt A.; Field, Kevin G.; Worrall, Andrew; Robb, Kevin R.; Yamamoto, Yukinori; Powers, Jeffrey J.; Dryepondt, Sebastien N.; Pint, Bruce A.; Hu, Xunxiang

    2015-06-01

    Technology implimentation plan for FeCrAl development under the FCRD Advanced Fuel program. The document describes the activities required to get FeCrAl clad ready for LTR testing

  9. Audit Report: CR-B-01-01 | Department of Energy

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

    Audit Report: CR-B-01-01 May 9, 2001 Issues Regarding Fee Structure for Three Environmental Management Contracts PDF icon Audit Report: CR-B-01-01 More Documents & Publications ...

  10. Audit Report: CR-B-96-01 | Department of Energy

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

    Audit Report: CR-B-96-01 May 24, 1996 The Federal Energy Regulatory Commission Leased Warehouse Space PDF icon Audit Report: CR-B-96-01 More Documents & Publications Semiannual ...

  11. Audit Report: CR-B-97-02 | Department of Energy

    Office of Environmental Management (EM)

    2 Audit Report: CR-B-97-02 April 4, 1997 Audit of Department of Energy's Contractor Salary Increase Funds Audit Report: CR-B-97-02 More Documents & Publications Inspection Report:...

  12. Audit Report: CR-FS-97-02 | Department of Energy

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

    FS-97-02 Audit Report: CR-FS-97-02 May 1, 1997 Audit of the Department of Energy's Consolidated Financial Statements for Fiscal Year 1996 Audit Report: CR-FS-97-02 More Documents &...

  13. Audit Report: CR-B-95-03 | Department of Energy

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

    Audit Report: CR-B-95-03 February 6, 1995 Audit of the Department of Energy's Security Police Officer Training PDF icon Audit Report: CR-B-95-03 More Documents & Publications Type...

  14. The crystal and magnetic structure of Ti-substituted LaCrO{sub...

    Office of Scientific and Technical Information (OSTI)

    On account of a miscibility gap, a higher degree of Ti-substitution at the Cr site cannot be achieved; as a consequence the solid state solubility of Ti in LaCrOsub 3 at 1573 K ...

  15. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

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

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; et al

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reachmore »the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.« less

  16. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

    SciTech Connect (OSTI)

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; Rory Kennedy, J.

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reach the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.

  17. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

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

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; et al

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reachmore » the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.« less

  18. Non-classical nuclei and growth kinetics of Cr precipitates in FeCr alloys during ageing

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Zhang, Lei; Sun, Xin

    2014-01-10

    In this manuscript, we quantitatively calculated the thermodynamic properties of critical nuclei of Cr precipitates in FeCr alloys. The concentration profiles of the critical nuclei and nucleation energy barriers were predicted by the constrained shrinking dimer dynamics (CSDD) method. It is found that Cr concentration distribution in the critical nuclei strongly depend on the overall Cr concentration as well as temperature. The critical nuclei are non-classical because the concentration in the nuclei is smaller than the thermodynamic equilibrium value. These results are in agreement with atomic probe observation. The growth kinetics of both classical and non-classical nuclei was investigated by the phase field approach. The simulations of critical nucleus evolution showed a number of interesting phenomena: 1) a critical classical nucleus first shrinks toward its non-classical nucleus and then grows; 2) a non-classical nucleus has much slower growth kinetics at its earlier growth stage compared to the diffusion-controlled growth kinetics. 3) a critical classical nucleus grows faster at the earlier growth stage than the non-classical nucleus. All of these results demonstrate that it is critical to introduce the correct critical nuclei in order to correctly capture the kinetics of precipitation.

  19. Surface half-metallicity of CrS thin films and perfect spin filtering and spin diode effects of CrS/ZnSe heterostructure

    SciTech Connect (OSTI)

    Gao, G. Y. Yao, K. L.

    2014-11-03

    Recently, ferromagnetic zinc-blende Mn{sub 1−x}Cr{sub x}S thin films (above x = 0.5) were fabricated experimentally on ZnSe substrate, which confirmed the previous theoretical prediction of half-metallic ferromagnetism in zinc-blende CrS. Here, we theoretically reveal that both Cr- and S-terminated (001) surfaces of the CrS thin films retain the half-metallicity. The CrS/ZnSe(001) heterogeneous junction exhibits excellent spin filtering and spin diode effects, which are explained by the calculated band structure and transmission spectra. The perfect spin transport properties indicate the potential applications of half-metallic CrS in spintronic devices. All computational results are obtained by using the density functional theory combined with nonequilibrium Green's function.

  20. Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations

    SciTech Connect (OSTI)

    Wang, Guofeng; Van Hove, M.A.; Ross, P.N.; Baskes, M.I.

    2005-03-31

    The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, and with Pt concentrations from 60 to 90 at. percent. The equilibrium Pt-Mo nanoparticle configurations were generated through Monte Carlo simulations allowing both atomic displacements and element exchanges at 600 K. We predict that the Pt atoms weakly segregate to the surfaces of such nanoparticles. The Pt concentrations in the surface are calculated to be 5 to 14 at. percent higher than the Pt concentrations of the nanoparticles. Moreover, the Pt atoms preferentially segregate to the facet sites of the surface, while the Pt and Mo atoms tend to alternate along the edges and vertices of these nanoparticles. We found that decreasing the size or increasing the Pt concentration leads to higher Pt concentrations but fewer Pt-Mo pairs in the Pt-Mo nanoparticle surfaces.

  1. Spectroscopic signatures of AA' and AB stacking of chemical vapor deposited bilayer MoS2

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

    Xia, Ming; Li, Bo; Yin, Kuibo; Capellini, Giovanni; Niu, Gang; Gong, Yongji; Zhou, Wu; Ajayan, Pulickel M.; Xie, Ya -Hong

    2015-11-04

    We discuss prominent resonance Raman and photoluminescence spectroscopic differences between AA'and AB stacked bilayer molybdenum disulfide (MoS2) grown by chemical vapor deposition are reported. Bilayer MoS2 islands consisting of the two stacking orders were obtained under identical growth conditions. Also, resonance Raman and photoluminescence spectra of AA' and AB stacked bilayer MoS2 were obtained on Au nanopyramid surfaces under strong plasmon resonance. Both resonance Raman and photoluminescence spectra show distinct features indicating clear differences in interlayer interaction between these two phases. The implication of these findings on device applications based on spin and valley degrees of freedom.

  2. New Insights Into a Functioning Mg-ion Cathode-Chevrel Phase Mo6S8 -

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

    Joint Center for Energy Storage Research April 24, 2014, Research Highlights New Insights Into a Functioning Mg-ion Cathode-Chevrel Phase Mo6S8 An isosurface of the charge density difference between pristine Mo6S8 and the inclusion of a single Mg2+ intercalant (and accompanying 2 electrons). Colors: Yellow (cyan) indicates an increase (decrease) in electron density, the Mg atom is shown in orange, S yellow, Mo purple. Scientific Achievement First-principles analysis of the screening of Mg2+

  3. PylotDB - A Database Management, Graphing, and Analysis Tool Written in Python

    SciTech Connect (OSTI)

    2012-01-04

    PylotDB, written completely in Python, provides a user interface (UI) with which to interact with, analyze, graph data from, and manage open source databases such as MySQL. The UI mitigates the user having to know in-depth knowledge of the database application programming interface (API). PylotDB allows the user to generate various kinds of plots from user-selected data; generate statistical information on text as well as numerical fields; backup and restore databases; compare database tables across different databases as well as across different servers; extract information from any field to create new fields; generate, edit, and delete databases, tables, and fields; generate or read into a table CSV data; and similar operations. Since much of the database information is brought under control of the Python computer language, PylotDB is not intended for huge databases for which MySQL and Oracle, for example, are better suited. PylotDB is better suited for smaller databases that might be typically needed in a small research group situation. PylotDB can also be used as a learning tool for database applications in general.

  4. PylotDB - A Database Management, Graphing, and Analysis Tool Written in Python

    Energy Science and Technology Software Center (OSTI)

    2012-01-04

    PylotDB, written completely in Python, provides a user interface (UI) with which to interact with, analyze, graph data from, and manage open source databases such as MySQL. The UI mitigates the user having to know in-depth knowledge of the database application programming interface (API). PylotDB allows the user to generate various kinds of plots from user-selected data; generate statistical information on text as well as numerical fields; backup and restore databases; compare database tables acrossmore » different databases as well as across different servers; extract information from any field to create new fields; generate, edit, and delete databases, tables, and fields; generate or read into a table CSV data; and similar operations. Since much of the database information is brought under control of the Python computer language, PylotDB is not intended for huge databases for which MySQL and Oracle, for example, are better suited. PylotDB is better suited for smaller databases that might be typically needed in a small research group situation. PylotDB can also be used as a learning tool for database applications in general.« less

  5. Cr.sup.3+ -doped colquiriite solid state laser material

    DOE Patents [OSTI]

    Payne, Stephen A.; Chase, Lloyd L.; Newkirk, Herbert W.; Krupke, William F.

    1989-01-01

    Chromium doped colquiriite, LiCaAlF.sub.6 :Cr.sup.3+, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr.sup.3+ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slop efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd.sup.3+ or Tm.sup.3+ for use in a multimegajoule single shot fusion research facility.

  6. Cr/sup 3 +/-doped colquiriite solid state laser material

    DOE Patents [OSTI]

    Payne, S.A.; Chase, L.L.; Newkirk, H.W.; Krupke, W.F.

    1988-03-31

    Chromium doped colquiriite, LiCaAlF/sub 6/:Cr/sup 3 +/, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr/sup 3 +/ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slope efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd/sup 3 +/ or Tm/sup 3 +/ for use in a multimegajoule single shot fusion research facility. 4 figs.

  7. Cr{sub 2}Nb-based alloy development

    SciTech Connect (OSTI)

    Liu, C.T.; Horton, J.A.; Carmichael, C.A.

    1996-05-01

    This paper summarizes recent progress in developing Cr{sub 2}Nb/Cr(Nb) alloys for structural use in advanced fossil energy conversion systems. Alloy additions were added to control the microstructure and mechanical properties. Two beneficial elements have been identified among all alloying additions added to the alloys. One element is effective in refining the coarse eutectic structure and thus substantially improves the compressive strength and ductility of the alloys. The other element enhances oxidation resistance without sacrificing the ductility. The tensile properties are sensitive to cast defects, which can not be effectively reduced by HIPping at 1450-1580{degrees}C and/or directionally solidifying via a floating zone remelting method.

  8. Transport signatures of quantum critically in Cr at high pressure.

    SciTech Connect (OSTI)

    Jaramillo, R.; Feng, Y.; Wang, J.; Rosenbaum, T. F.

    2010-08-03

    The elemental antiferromagnet Cr at high pressure presents a new type of naked quantum critical point that is free of disorder and symmetry-breaking fields. Here we measure magnetotransport in fine detail around the critical pressure, P{sub c} {approx} 10 GPa, in a diamond anvil cell and reveal the role of quantum critical fluctuations at the phase transition. As the magnetism disappears and T {yields} 0, the magntotransport scaling converges to a non-mean-field form that illustrates the reconstruction of the magnetic Fermi surface, and is distinct from the critical scaling measured in chemically disordered Cr:V under pressure. The breakdown of itinerant antiferromagnetism only comes clearly into view in the clean limit, establishing disorder as a relevant variable at a quantum phase transition.

  9. AmeriFlux CR-Lse La Selva

    SciTech Connect (OSTI)

    Loescher, Hank

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CR-Lse La Selva. Site Description - Site was occupied by Native Americans since 3000 B.P. practicing shifting cultivation. Some selective cutting along rivers (heart of palm). Charcoal dating indicate fires 2400 B.P. and 1100 B.P. Some clearing for pasture/cocoa production, second growth, humid tropical rain forest. Site resides on land presently owned by the Organization for Tropical Studies.

  10. SF6432-CR (02-01-13) Cost Reimbursement

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

    Department Release Date: 11/17/15 Page 1 of 25 Printed copies of this document are uncontrolled. Retrieve latest version electronically. SANDIA CORPORATION SF 6432-CR (11/2015) SECTION II STANDARD TERMS AND CONDITIONS FOR COST-REIMBURSEMENT CONTRACTS THE FOLLOWING CLAUSES APPLY TO THIS CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY IDENTIFIED AS BEING CHANGED, SUPPLEMENTED, OR AMENDED IN WRITING ISSUED BY THE SANDIA CONTRACTING REPRESENTATIVE.

  11. SF6432-CR (02-01-13) Cost Reimbursement

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

    7/31/13 Page 1 of 24 Printed copies of this document are uncontrolled. Retrieve latest version electronically. SANDIA CORPORATION SF 6432-CR (07/2013) SECTION II STANDARD TERMS AND CONDITIONS FOR COST-REIMBURSEMENT CONTRACTS THE FOLLOWING CLAUSES APPLY TO THIS CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY IDENTIFIED AS BEING CHANGED, SUPPLEMENTED, OR AMENDED IN WRITING ISSUED BY THE SANDIA CONTRACTING REPRESENTATIVE. (CTRL+CLICK ON A LINK BELOW

  12. Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal

    SciTech Connect (OSTI)

    Kaur, Maninder; Dai, Qilin; Bowden, Mark E.; Engelhard, Mark H.; Wu, Yaqiao; Tang, Jinke; Qiang, You

    2013-06-26

    Chromium (Cr) forms a solid solution with iron (Fe) lattice when doped in core-shell iron -iron oxide nanocluster (NC) and shows a mixed phase of sigma (?) FeCr and bcc Fe. The Cr dopant affects heavily the magnetization and magnetic reversal process, and causes the hysteresis loop to shrink near the zero field axis. Dramatic transformation happens from dipolar interaction (0 at. % Cr) to strong exchange interaction (8 at. % of Cr) is confirmed from the Henkel plot and delta M plot, and is explained by a water-melon model of core-shell NC system.

  13. Low temperature spin dynamics in Cr{sub 7}Ni-Cu-Cr{sub 7}Ni coupled molecular rings

    SciTech Connect (OSTI)

    Bordonali, L.; Furukawa, Y.; Mariani, M.; Sabareesh, K. P. V.; Garlatti, E.; Borsa, F.

    2014-05-07

    Proton Nuclear Magnetic Resonance (NMR) relaxation measurements have been performed down to very low temperature (50 mK) to determine the effect of coupling two Cr{sub 7}Ni molecular rings via a Cu{sup 2+} ion. No difference in the spin dynamics was found from nuclear spin lattice relaxation down to 1.5 K. At lower temperature, the {sup 1}H-NMR line broadens dramatically indicating spin freezing. From the plot of the line width vs. magnetization, it is found that the freezing temperature is higher (260 mK) in the coupled ring with respect to the single Cr{sub 7}Ni ring (140 mK)

  14. Thermo-physical Properties of DU-10 wt.% Mo Alloys

    SciTech Connect (OSTI)

    Douglas E. Burkes; Cynthia A. Papesch; Andrew P. Maddison; Thomas Hartmann; Francine J. Rice

    2010-08-01

    Low-enriched uranium alloyed with 10 wt% molybdenum is under consideration by the Global Threat Reduction Initiative reactor convert program as a very high density fuel to enable the conversion of high-performance research reactors away from highly-enriched uranium fuels. As with any fuel development program, the thermophysical properties of the fuel as a function of temperature are extremely important and must be well characterized in order to effectively model and predict fuel behavior under normal and off-normal irradiation conditions. For the alloy system under investigation, there is a lack of thermophysical property data, and in most cases, the data is relatively inconsistent and lacks sufficient explanation. Available literature on this alloy system comes mainly from studies done during the 1960s and 1970s, and often does not include sufficient information on fabrication history or conditions to draw conclusions for the current application. The current paper has investigated specific heat capacity, coefficient of linear thermal expansion, density, and thermal diffusivity that were then used to calculate alloy thermal conductivity as a function of temperature. The data obtained from this investigation was compared to available literature on similar U-Mo alloys, and in most cases are in good agreement.

  15. Structure and Electronic Properties of MoVO type Mixed-metal...

    Office of Scientific and Technical Information (OSTI)

    and Theory Citation Details In-Document Search Title: Structure and Electronic Properties of MoVO type Mixed-metal Oxides a Combined View by Experiment and Theory Authors: ...

  16. NNSA Works to Establish a Reliable Supply of Mo-99 Produced Without...

    National Nuclear Security Administration (NNSA)

    DOENNSA's objective is to accelerate the establishment of a reliable, commercial Mo-99 supply network that avoids a single point of failure and does not use proliferation-sensitiv...

  17. Giant and tunable valley degeneracy splitting in MoTe 2 (Journal...

    Office of Scientific and Technical Information (OSTI)

    This content will become publicly available on September 7, 2016 Title: Giant and tunable valley degeneracy splitting in MoTe 2 Authors: Qi, Jingshan ; Li, Xiao ; Niu, Qian ; Feng, ...

  18. Monolayers of MoS{sub 2} as an oxidation protective nanocoating material

    SciTech Connect (OSTI)

    Sen, H. Sener; Sahin, H.; Peeters, F. M.; Durgun, E.

    2014-08-28

    First-principle calculations are employed to investigate the interaction of oxygen with ideal and defective MoS{sub 2} monolayers. Our calculations show that while oxygen atoms are strongly bound on top of sulfur atoms, the oxygen molecule only weakly interacts with the surface. The penetration of oxygen atoms and molecules through a defect-free MoS{sub 2} monolayer is prevented by a very high diffusion barrier indicating that MoS{sub 2} can serve as a protective layer for oxidation. The analysis is extended to WS{sub 2} and similar coating characteristics are obtained. Our calculations indicate that ideal and continuous MoS{sub 2} and WS{sub 2} monolayers can improve the oxidation and corrosion-resistance of the covered surface and can be considered as an efficient nanocoating material.

  19. Microscopic origin of low frequency noise in MoS{sub 2} field-effect transistors

    SciTech Connect (OSTI)

    Ghatak, Subhamoy; Jain, Manish; Ghosh, Arindam; Mukherjee, Sumanta; Sarma, D. D.

    2014-09-01

    We report measurement of low frequency 1/f noise in molybdenum di-sulphide (MoS{sub 2}) field-effect transistors in multiple device configurations including MoS{sub 2} on silicon dioxide as well as MoS{sub 2}-hexagonal boron nitride (hBN) heterostructures. All as-fabricated devices show similar magnitude of noise with number fluctuation as the dominant mechanism at high temperatures and density, although the calculated density of traps is two orders of magnitude higher than that at the SiO{sub 2} interface. Measurements on the heterostructure devices with vacuum annealing and dual gated configuration reveals that along with the channel, metal-MoS{sub 2} contacts also play a significant role in determining noise magnitude in these devices.

  20. File:USDA-CE-Production-GIFmaps-MO.pdf | Open Energy Information

    Open Energy Info (EERE)

    MO.pdf Jump to: navigation, search File File history File usage Missouri Ethanol Plant Locations Size of this preview: 776 600 pixels. Full resolution (1,650 1,275 pixels,...

  1. AB INITIO Modeling of Thermomechanical Properties of Mo-Based Alloys for Fossil Energy Conversion

    SciTech Connect (OSTI)

    Ching, Wai-Yim

    2013-12-31

    In this final scientific/technical report covering the period of 3.5 years started on July 1, 2011, we report the accomplishments on the study of thermo-mechanical properties of Mo-based intermetallic compounds under NETL support. These include computational method development, physical properties investigation of Mo-based compounds and alloys. The main focus is on the mechanical and thermo mechanical properties at high temperature since these are the most crucial properties for their potential applications. In particular, recent development of applying ab initio molecular dynamic (AIMD) simulations to the T1 (Mo{sub 5}Si{sub 3}) and T2 (Mo{sub 5}SiB{sub 2}) phases are highlighted for alloy design in further improving their properties.

  2. Substrate interactions with suspended and supported monolayer MoS2: Angle-resolved photoemission spectroscopy

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

    Jin, Wencan; Yeh, Po -Chun; Zaki, Nader; Zhang, Datong; Liou, Jonathan T.; Dadap, Jerry I.; Barinov, Alexey; Yablonskikh, Mikhail; Sadowski, Jerzy T.; Sutter, Peter; et al

    2015-03-17

    We report the directly measured electronic structure of exfoliated monolayer molybdenum disulfide (MoS₂) using micrometer-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer MoS₂ elucidate the effects of interaction with a substrate. Thus, a suggested relaxation of the in-plane lattice constant is found for both suspended and supported monolayer MoS₂ crystals. For suspended MoS₂, a careful investigation of the measured uppermost valence band gives an effective mass at Γ¯ and Κ¯ of 2.00m₀ and 0.43m₀, respectively. We also measure an increase in the band linewidth from the midpoint of Γ¯Κ¯ to the vicinity of Κ¯ and briefly discussmore » its possible origin.« less

  3. Dynamic Structural Response and Deformations of Monolayer MoS 2 Visualized

    Office of Scientific and Technical Information (OSTI)

    by Femtosecond Electron Diffraction (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Dynamic Structural Response and Deformations of Monolayer MoS 2 Visualized by Femtosecond Electron Diffraction Citation Details In-Document Search Title: Dynamic Structural Response and Deformations of Monolayer MoS 2 Visualized by Femtosecond Electron Diffraction Authors: Mannebach, Ehren M. ; Li, Renkai ; Duerloo, Karel-Alexander ; Nyby, Clara ; Zalden, Peter ; Vecchione,

  4. U-EXTRACTION--IMPROVEMENTS IN ELIMINATION OF Mo BY USE OF FERRIC ION

    DOE Patents [OSTI]

    Clark, H.M.; Duffey, D.

    1958-06-10

    An improved solvent extraction process is described whereby U may be extracted by a water immiscible organic solvent from an aqueous solution of uranyl nitrate. It has been found that Mo in the presence of phosphate ions appears to form a complex with the phosphate which extracts along with the U. This extraction of Mo may be suppressed by providing ferric ion in the solution prior to the extraction step. The ferric ion is preferably provided in the form of ferric nitrate.

  5. Rotationally Commensurate Growth of MoS[subscript 2] on Epitaxial Graphene

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Rotationally Commensurate Growth of MoS[subscript 2] on Epitaxial Graphene Citation Details In-Document Search Title: Rotationally Commensurate Growth of MoS[subscript 2] on Epitaxial Graphene Authors: Liu, Xiaolong ; Balla, Itamar ; Bergeron, Hadallia ; Campbell, Gavin P. ; Bedzyk, Michael J. ; Hersam, Mark C. [1] + Show Author Affiliations NWU Publication Date: 2016-03-04 OSTI Identifier: 1240188 Resource Type: Journal Article Resource Relation: Journal

  6. Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding Citation Details In-Document Search Title: Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding Authors: Cheng, Bo ; Kim, Young-Jin ; Chou, Peter Publication Date: 2016-02-01 OSTI Identifier: 1253199 Type: Published Article Journal Name: Nuclear Engineering and Technology Additional Journal Information: Journal Volume: 48; Journal Issue: 1; Related Information:

  7. Li Intercalation in MoS 2 : In Situ Observation of Its Dynamics and Tuning

    Office of Scientific and Technical Information (OSTI)

    Optical and Electrical Properties (Journal Article) | SciTech Connect Li Intercalation in MoS 2 : In Situ Observation of Its Dynamics and Tuning Optical and Electrical Properties Citation Details In-Document Search Title: Li Intercalation in MoS 2 : In Situ Observation of Its Dynamics and Tuning Optical and Electrical Properties Authors: Xiong, Feng ; Wang, Haotian ; Liu, Xiaoge ; Sun, Jie ; Brongersma, Mark ; Pop, Eric ; Cui, Yi Publication Date: 2015-10-14 OSTI Identifier: 1244610 DOE

  8. Climate Action Champions: Mid-America Regional Council, KS and MO |

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

    Department of Energy Mid-America Regional Council, KS and MO Climate Action Champions: Mid-America Regional Council, KS and MO The Mid-America Regional Council (MARC) is a nonprofit association of city and county governments and the metropolitan planning organization for the bistate Kansas City region. They provide a forum for the region to work together to advance social, economic and environmental progress. MARC received the Climate Action Champion designation in consortium with the City

  9. Valence and metal/silicate partitioning of Mo: Implications for conditions

    Office of Scientific and Technical Information (OSTI)

    of Earth accretion and core formation (Journal Article) | SciTech Connect Valence and metal/silicate partitioning of Mo: Implications for conditions of Earth accretion and core formation Citation Details In-Document Search Title: Valence and metal/silicate partitioning of Mo: Implications for conditions of Earth accretion and core formation Authors: Righter, K. ; Danielson, L. R. ; Pando, K. M. ; Shofner, G. A. ; Sutton, S. R. ; Newville, M. ; Lee, C. -T. [1] ; UC) [2] ; Rice) [2] + Show

  10. MoS{sub 2} nanotube exfoliation as new synthesis pathway to molybdenum blue

    SciTech Connect (OSTI)

    Visic, B.; Gunde, M. Klanjsek; Kovac, J.; Iskra, I.; Jelenc, J.; Remskar, M.; Centre of Excellence Namaste, Jamova cesta 39, SI-1000 Ljubljana

    2013-02-15

    Graphical abstract: . Display Omitted Highlights: ? New synthesis approach to obtaining molybdenum blue via exfoliated MoS{sub 2} nanotubes. ? Material is prone to self assembly and is stable in high vacuum. ? Molecules are as small as 2 nm and their clusters are up to tens of nanometers. ? Change in absorption and oxidation states from the precursor MoS{sub 2}. -- Abstract: Molybdenum blue-type materials are usually obtained by partially reducing Mo{sup VI+} in acidic solutions, while in the presented method it is formed in ethanol solution of exfoliated MoS{sub 2} nanotubes, where the MoS{sub 2} flakes are the preferential location for their growth. Material was investigated by means of scanning electron and atomic force microscopy, showing the structure and self assembly, while also confirming that it is stable in high vacuum with molecules as small as 1.6 nm and the agglomerates of few tens of nanometres. The ultravioletvisible and photoelectron spectrometry show the change in absorption properties and oxidation states from MoS{sub 2} structure to molybdenum blue, while the presence of sulphur suggests that this is a new type of molybdenum blue material.

  11. Effects of thermal treatment on the co-rolled U-Mo fuel foils

    SciTech Connect (OSTI)

    Dennis D. Keiser, Jr.; Tammy L. Trowbridge; Cynthia R. Breckenridge; Brady L. Mackowiak; Glenn A. Moore; Barry H. Rabin; Mitchell K. Meyer

    2014-11-01

    A monolithic fuel type is being developed to convert US high performance research and test reactors such as Advanced Test Reactor (ATR) at Idaho National Laboratory from highly enriched uranium (HEU) to low-enriched uranium (LEU). The interaction between the cladding and the U-Mo fuel meat during fuel fabrication and irradiation is known to have negative impacts on fuel performance, such as mechanical integrity and dimensional stability. In order to eliminate/minimize the direct interaction between cladding and fuel meat, a thin zirconium diffusion barrier was introduced between the cladding and U-Mo fuel meat through a co-rolling process. A complex interface between the zirconium and U-Mo was developed during the co-rolling process. A predictable interface between zirconium and U-Mo is critical to achieve good fuel performance since the interfaces can be the weakest link in the monolithic fuel system. A post co-rolling annealing treatment is expected to create a well-controlled interface between zirconium and U-Mo. A systematic study utilizing post co-rolling annealing treatment has been carried out. Based on microscopy results, the impacts of the annealing treatment on the interface between zirconium and U-Mo will be presented and an optima annealing treatment schedule will be suggested. The effects of the annealing treatment on the fuel performance will also be discussed.

  12. High reflectance and low stress Mo2C/Be multilayers

    DOE Patents [OSTI]

    Bajt, Sasa; Barbee, Jr., Troy W.

    2001-01-01

    A material for extreme ultraviolet (EUV) multilayers that will reflect at about 11.3 nm, have a high reflectance, low stress, and high thermal and radiation stability. The material consists of alternating layers of Mo.sub.2 C and Be deposited by DC magnetron sputtering on a substrate, such as silicon. In one example a Mo.sub.2 C/Be multilayer gave 65.2% reflectance at 11.25 nm measured at 5 degrees off normal incidence angle, and consisted of 70 bilayers with a deposition period of 5.78 nm, and was deposited at 0.83 mTorr argon (Ar) sputtering pressure, with the first and last layers being Be. The stress of the multilayer is tensile and only +88 MPa, compared to +330 MPa of a Mo/Be multilayers of the same thickness. The Mo.sub.2 C/Be multilayer was capped with carbon which produced an increase in reflectivity of about 7% over a similar multilayer with no carbon capping material, thus raising the reflectivity from 58.3% to over 65%. The multilayers were formed using either Mo.sub.2 C or Be as the first and last layers, and initial testing has shown the formation of beryllium carbide at the interfaces between the layers which both stabilizes and has a smoothing effect, and appear to be smoother than the interfaces in Mo/Be multilayers.

  13. Microstructure evolution of Li uptake/removal in MoO{sub 2}@C nanoparticles with high lithium storage performance

    SciTech Connect (OSTI)

    Liu, Yulong; Zhang, Hong; Ouyang, Pan; Chen, Wenhao [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Zhicheng, E-mail: zhchli@mail.csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2014-02-01

    Highlights: The carbon-coated MoO{sub 2} (MoO{sub 2}@C) ultra fine nanoparticles are synthesized by one-pot hydrothermal method. MoO{sub 2}@C nanoparticles have high specific capacity, excellent cycling performance and rate performance. Phase transformations for lithium ion uptake/removal are examined carefully by TEM. Phase transformations are highly reversible during the redox process. - Abstract: A facile one pot strategy of a hydrothermal methodology was applied to synthesize the carbon coated MoO{sub 2} (MoO{sub 2}@C) nanostructured particles, which are composed of ultra fine nanoparticles with homogeneous carbon coating about several nanometers. As an electrode in lithium ion batteries, the MoO{sub 2}@C shows a high specific capacity and reversible capacity (730 mA h g{sup ?1} after 60 cycles). Microstructure investigations, by using a high resolution transmission electron microscopy, of the MoO{sub 2}@C based electrodes employed at various states during the first discharge/charge cycle were conducted to elucidate the lithium ion uptake/removal mechanism and cycling behavior. In the lithium uptake process, the original MoO{sub 2} phase transfers into Li{sub 0.98}MoO{sub 2} through an addition type reaction, and then nanosized metallic Mo emerges as a result of a conversion reaction. In turn, Mo could be oxidized to the intermediate Li{sub 0.98}MoO{sub 2} before converting to hyperfine MoO{sub 2} phase on upcoming lithium removal process.

  14. Cr(OH)₃(s) Oxidation Induced by Surface Catalyzed Mn(II) Oxidation

    SciTech Connect (OSTI)

    Namgung, Seonyi; Kwon, M.; Qafoku, Nikolla; Lee, Gie Hyeon

    2014-09-16

    This study examined the feasibility of Cr(OH)₃(s) oxidation mediated by surface catalyzed Mn(II) oxidation under common groundwater pH conditions as a potential pathway of natural Cr(VI) contaminations. Dissolved Mn(II) (50 μM) was reacted with or without synthesized Cr(OH)₃(s) (1.0 g/L) at pH 7 – 9 under oxic or anoxic conditions. In the absence of Cr(OH)₃(s), homogeneous Mn(II) oxidation by dissolved O₂ was not observed at pH ≤ 8.0 for 50 d. At pH 9.0, by contrast, dissolved Mn(II) was completely removed within 8 d and precipitated as hausmannite. When Cr(OH)₃(s) was present, this solid was oxidized and released substantial amounts of Cr(VI) as dissolved Mn(II) was added into the suspension at pH ≥ 8.0 under oxic conditions. Our results suggest that Cr(OH)₃(s) was readily oxidized by a newly formed Mn oxide as a result of Mn(II) oxidation catalyzed on Cr(OH)₃(s) surface. XANES analysis of the residual solids after the reaction between 1.0 g/L Cr(OH)₃(s) and 204 μM Mn(II) at pH 9.0 for 22 d revealed that the product of surface catalyzed Mn(II) oxidation resembled birnessite. The rate and extent of Cr(OH)₃(s) oxidation was likely controlled by those of surface catalyzed Mn(II) oxidation as the production of Cr(VI) increased with increasing pH and initial Mn(II) concentrations. This study evokes the potential environmental hazard of sparingly soluble Cr(OH)₃(s) that can be a source of Cr(VI) in the presence of dissolved Mn(II).

  15. Oxidation sulfidation resistance of Fe-Cr-Ni alloys

    DOE Patents [OSTI]

    Natesan, Ken (Naperville, IL); Baxter, David J. (Woodridge, IL)

    1984-01-01

    High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1-8 wt. % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500.degree.-1000.degree. C.

  16. Improved oxidation sulfidation resistance of Fe-Cr-Ni alloys

    DOE Patents [OSTI]

    Natesan, K.; Baxter, D.J.

    1983-07-26

    High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1 to 8 wt % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500 to 1000/sup 0/C.

  17. MCNPX-CINDER'90 Simulation of Photonuclear Mo-99 Production Experiments

    SciTech Connect (OSTI)

    Kelsey, Charles T. IV [Los Alamos National Laboratory; Chemerizov, Sergey D. [Argonne National Laboratory; Dale, Gregory E. [Los Alamos National Laboratory; Harvey, James T. [NorthStar Medical Radioisotopes; Tkac, Peter [Argonne National Laboratory; Vandegrift, George R III [Argonne National Laboratory

    2011-01-01

    The MCNPX and CINDER'90 codes were used to support design of experiments investigating Mo-99 production with a 20-MeV electron beam. Bremsstrahlung photons produced by the electron beam interacting with the target drive the desired Mo-100({gamma},n)Mo-99 reaction, as well as many undesired reactions important to accurate prediction of radiation hazards. MCNPX is a radiation transport code and CINDER'90 is a transmutation code. They are routinely used together for accelerator activation calculations. Low energy neutron fluxes and production rates for nonneutron and high energy neutron induced reactions computed using MCNPX are inputs to CINDER'90. CINDER'90 presently has only a neutron reaction cross section library up to 25 MeV and normally the other reaction rates come from MCNPX physics models. For this work MCNPX photon flux tallies modified by energy response functions prepared from evaluated photonuclear cross section data were used to tally the reaction rates for CINDER'90 input. The cross section evaluations do not provide isomer to ground state yield ratios so a spin based approximation was used. Post irradiation dose rates were calculated using MCNPX with CINDER'90 produced decay photon spectra. The sensitivity of radionuclide activities and dose rates to beam parameters including energy, position, and profile, as well as underlying isomer assumptions, was investigated. Three experimental production targets were irradiated, two natural Mo and one Mo-100 enriched. Natural Mo foils upstream of the targets were used to analyze beam position and profile by exposing Gafchromic film to the foils after each irradiation. Activation and dose rate calculations were rerun after the experiments using measured beam parameters for comparison with measured Mo-99 activities and dose rates.

  18. Doping against the native propensity of MoS₂: Degenerate hole doping by cation substitution

    SciTech Connect (OSTI)

    Suh, Joonki; Park, Tae-Eon; Lin, Der-Yuh; Fu, Deyi; Park, Joonsuk; Jung, Hee Joon; Chen, Yabin; Ko, Changhyun; Jang, Chaun; Sun, Yinghui; Sinclair, Robert; Chang, Joonyeon; Tongay, Sefaattin; Wu, Junqiao

    2014-12-10

    Layered transition metal dichalcogenides (TMDs) draw much attention as the key semiconducting material for two-dimensional electrical, optoelectronic, and spintronic devices. For most of these applications, both n- and p-type materials are needed to form junctions and support bipolar carrier conduction. However, typically only one type of doping is stable for a particular TMD. For example, molybdenum disulfide (MoS₂) is natively an n-type presumably due to omnipresent electron-donating sulfur vacancies, and stable/controllable p-type doping has not been achieved. The lack of p-type doping hampers the development of charge-splitting p–n junctions of MoS₂, as well as limits carrier conduction to spin-degenerate conduction bands instead of the more interesting, spin-polarized valence bands. Traditionally, extrinsic p-type doping in TMDs has been approached with surface adsorption or intercalation of electron-accepting molecules. However, practically stable doping requires substitution of host atoms with dopants where the doping is secured by covalent bonding. In this work, we demonstrate stable p-type conduction in MoS₂ by substitutional niobium (Nb) doping, leading to a degenerate hole density of ~3 × 10¹⁹ cm⁻³. Structural and X-ray techniques reveal that the Nb atoms are indeed substitutionally incorporated into MoS₂ by replacing the Mo cations in the host lattice. van der Waals p–n homojunctions based on vertically stacked MoS₂ layers are fabricated, which enable gate-tunable current rectification. A wide range of microelectronic, optoelectronic, and spintronic devices can be envisioned from the demonstrated substitutional bipolar doping of MoS₂. From the miscibility of dopants with the host, it is also expected that the synthesis technique demonstrated here can be generally extended to other TMDs for doping against their native unipolar propensity.

  19. Irradiation-enhanced α' precipitation in model FeCrAl alloys

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

    Edmondson, Philip D.; Briggs, Samuel A.; Yamamoto, Yukinori; Howard, Richard H.; Sridharan, Kumar; Terrani, Kurt A.; Field, Kevin G.

    2016-02-17

    Model FeCrAl alloys with varying compositions (Fe(10–18)Cr(10–6)Al at.%) have been neutron irradiated at ~ 320 to damage levels of ~ 7 displacements per atom (dpa) to investigate the compositional influence on the formation of irradiation-induced Cr-rich α' precipitates using atom probe tomography. In all alloys, significant number densities of these precipitates were observed. Cluster compositions were investigated and it was found that the average cluster Cr content ranged between 51.1 and 62.5 at.% dependent on initial compositions. This is significantly lower than the Cr-content of α' in binary FeCr alloys. As a result, significant partitioning of the Al from themore » α' precipitates was also observed.« less

  20. Ferromagnetism at room temperature in Cr-doped anodic titanium dioxide nanotubes

    SciTech Connect (OSTI)

    Liao, Yulong E-mail: hwzhang@uestc.edu.cn; Zhang, Huaiwu E-mail: hwzhang@uestc.edu.cn; Li, Jie; Yu, Guoliang; Zhong, Zhiyong; Bai, Feiming; Jia, Lijun; Zhang, Shihong; Zhong, Peng

    2014-05-07

    This study reports the room-temperature ferromagnetism in Cr-doped TiO{sub 2} nanotubes (NTs) synthesized via the electrochemical method followed by a novel Cr-doping process. Scanning electron microscopy and transmission electron microscopy showed that the TiO{sub 2} NTs were highly ordered with length up to 26 ?m, outer diameter about 110 nm, and inner diameter about 100 nm. X-ray diffraction results indicated there were no magnetic contaminations of metallic Cr clusters or any other phases except anatase TiO{sub 2}. The Cr-doped TiO{sub 2} NTs were further annealed in oxygen, air and argon, and room-temperature ferromagnetism was observed in all Cr-doped samples. Moreover, saturation magnetizations and coercivities of the Cr-doped under various annealing atmosphere were further analyzed, and results indicate that oxygen content played a critical role in the room-temperature ferromagnetism.

  1. Effects of Cr doping on the magnetic properties of multiferroic YMnO{sub 3}

    SciTech Connect (OSTI)

    Han, Tai-Chun Wu, I-Chu; Hsu, Hsin-Kai

    2014-05-07

    We have synthesized a series of YMn{sub 1?x}Cr{sub x}O{sub 3} (0???x???0.1) samples and study the effect of Cr-doping on their magnetic properties. The magnetic characterization indicates that with increasing Cr-content up to 0.1, the antiferromagnetic (AFM) transition temperature increases from 73 to 89?K. Our experiment results also indicate that the Cr-doped samples exhibit the characteristics of spin-glass state at low temperature. Moreover, the magnetic hysteresis curves of the doped samples show a weak ferromagnetic (FM) behavior. It is found that the spin-glass state of the Cr-doped samples is due to the competition between AFM superexchange and FM double-exchange interaction, induced by the Cr doping.

  2. The response of CR-39 nuclear track detector to 1-9 MeV protons

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

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; et al

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather thanmore » the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.« less

  3. Highly tunable magnetism in silicene doped with Cr and Fe atoms under

    Office of Scientific and Technical Information (OSTI)

    isotropic and uniaxial tensile strain (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Highly tunable magnetism in silicene doped with Cr and Fe atoms under isotropic and uniaxial tensile strain Citation Details In-Document Search Title: Highly tunable magnetism in silicene doped with Cr and Fe atoms under isotropic and uniaxial tensile strain We have investigated the magnetic properties of silicene doped with Cr and Fe atoms under isotropic and uniaxial

  4. EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM (Cr II)

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM (Cr II) Citation Details In-Document Search Title: EXTENDED ANALYSIS OF THE SPECTRUM OF SINGLY IONIZED CHROMIUM (Cr II) We have made new observations of the spectrum of singly ionized chromium (Cr II) in the region 2850-37900 Å with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. These data extend our previously reported observations in the

  5. In Situ Time-Resolved Characterization of Ni-MoO2 Catalysts for the Water-Gas Shift Reaction

    SciTech Connect (OSTI)

    Wen,W.; Calderon, J.; Brito, J.; Marinkovic, N.; Hanson, J.; Rodriquez, J.

    2008-01-01

    Active catalysts for the water-gas shift (WGS, CO + H2O ? H2 + CO2) reaction were synthesized from nickel molybdates ({beta}-NiMoO4 and nH2O{center_dot}NiMoO4) as precursors, and their structural transformations were monitored using in situ time-resolved X-ray diffraction and X-ray absorption near-edge spectroscopy. In general, the nickel molybdates were not stable and underwent partial reduction in the presence of CO or CO/H2O mixtures at high temperatures. The interaction of {beta}-NiMoO4 with the WGS reactants at 500 C led to the formation of a mixture of Ni (24 nm particle size) and MoO2 (10 nm particle size). These Ni-MoO2 systems displayed good catalytic activity at 350, 400, and 500 C. At 350 and 400 C, catalytic tests revealed that the Ni-MoO2 system was much more active than isolated Ni (some activity) or isolated MoO2 (negligible activity). Thus, cooperative interactions between the admetal and oxide support were probably responsible for the high WGS activity of Ni-MoO2. In a second synthetic approach, the NiMoO4 hydrate was reduced to a mixture of metallic Ni, NiO, and amorphous molybdenum oxide by direct reaction with H2 gas at 350 C. In the first pass of the water-gas shift reaction, MoO2 appeared gradually at 500 C with a concurrent increase of the catalytic activity. For these catalysts, the particle size of Ni (4 nm) was much smaller than that of the MoO2 (13 nm). These systems were found to be much more active WGS catalysts than Cu-MoO2, which in turn is superior to commercial low-temperature Cu-ZnO catalysts.

  6. Structural studies and band gap tuning of Cr doped ZnO nanoparticles

    SciTech Connect (OSTI)

    Srinet, Gunjan Kumar, Ravindra Sajal, Vivek

    2014-04-24

    Structural and optical properties of Cr doped ZnO nanoparticles prepared by the thermal decomposition method are presented. X-ray diffraction studies confirmed the substitution of Cr on Zn sites without changing the wurtzite structure of ZnO. Modified form of W-H equations was used to calculate various physical parameters and their variation with Cr doping is discussed. Significant red shift was observed in band gap, i.e., a band gap tuning is achieved by Cr doping which could eventually be useful for optoelectronic applications.

  7. Origin of spin gapless semiconductor behavior in CoFeCrGa: Theory...

    Office of Scientific and Technical Information (OSTI)

    behavior in CoFeCrGa: Theory and Experiment This content will become publicly available on July 8, 2016 Title: Origin of spin gapless semiconductor behavior in ...

  8. Hopping conduction in p-type MoS{sub 2} near the critical regime of the

    Office of Scientific and Technical Information (OSTI)

    metal-insulator transition (Journal Article) | SciTech Connect Hopping conduction in p-type MoS{sub 2} near the critical regime of the metal-insulator transition Citation Details In-Document Search Title: Hopping conduction in p-type MoS{sub 2} near the critical regime of the metal-insulator transition We report on temperature-dependent charge and magneto transport of chemically doped MoS{sub 2}, p-type molybdenum disulfide degenerately doped with niobium (MoS{sub 2}:Nb). The temperature

  9. Method for the production of {sup 99m}Tc compositions from {sup 99}Mo-containing materials

    DOE Patents [OSTI]

    Bennett, R.G.; Christian, J.D.; Grover, S.B.; Petti, D.A.; Terry, W.K.; Yoon, W.Y.

    1998-09-01

    An improved method is described for producing {sup 99m}Tc compositions from {sup 99}Mo compounds. {sup 100}Mo metal or {sup 100}MoO{sub 3} is irradiated with photons in a particle (electron) accelerator to ultimately produce {sup 99}MoO{sub 3}. This composition is then heated in a reaction chamber to form a pool of molten {sup 99}MoO{sub 3} with an optimum depth of 0.5--5 mm. A gaseous mixture thereafter evolves from the molten {sup 99}MoO{sub 3} which contains vaporized {sup 99}MoO{sub 3}, vaporized {sup 99m}TcO{sub 3}, and vaporized {sup 99m}TcO{sub 2}. This mixture is then combined with an oxidizing gas (O{sub 2(g)}) to generate a gaseous stream containing vaporized {sup 99m}Tc{sub 2}O{sub 7} and vaporized {sup 99}MoO{sub 3}. Next, the gaseous stream is cooled in a primary condensation stage in the reaction chamber to remove vaporized {sup 99}MoO{sub 3}. Cooling is undertaken at a specially-controlled rate to achieve maximum separation efficiency. The gaseous stream is then cooled in a sequential secondary condensation stage to convert vaporized {sup 99m}Tc{sub 2}O{sub 7} into a condensed {sup 99m}Tc-containing reaction product which is collected. 1 fig.

  10. Method for the production of .sup.99m Tc compositions from .sup.99 Mo-containing materials

    DOE Patents [OSTI]

    Bennett, Ralph G.; Christian, Jerry D.; Grover, S. Blaine; Petti, David A.; Terry, William K.; Yoon, Woo Y.

    1998-01-01

    An improved method for producing .sup.99m Tc compositions from .sup.99 Mo compounds. .sup.100 Mo metal or .sup.100 MoO.sub.3 is irradiated with photons in a particle (electron) accelerator to ultimately produce .sup.99 MoO.sub.3. This composition is then heated in a reaction chamber to form a pool of molten .sup.99 MoO.sub.3 with an optimum depth of 0.5-5 mm. A gaseous mixture thereafter evolves from the molten .sup.99 MoO.sub.3 which contains vaporized .sup.99 MoO.sub.3, vaporized .sup.99m TcO.sub.3, and vaporized .sup.99m TcO.sub.2. This mixture is then combined with an oxidizing gas (O.sub.2(g)) to generate a gaseous stream containing vaporized .sup.99m Tc.sub.2 O.sub.7 and vaporized .sup.99 MoO.sub.3. Next, the gaseous stream is cooled in a primary condensation stage in the reaction chamber to remove vaporized .sup.99 MoO.sub.3. Cooling is undertaken at a specially-controlled rate to achieve maximum separation efficiency. The gaseous stream is then cooled in a sequential secondary condensation stage to convert vaporized .sup.99m Tc.sub.2 O.sub.7 into a condensed .sup.99m Tc-containing reaction product which is collected.

  11. FeAl and Mo-Si-B Intermetallic Coatings Prepared by Thermal Spraying

    SciTech Connect (OSTI)

    Totemeier, T.C.; Wright, R.N.; Swank, W.D.

    2003-04-22

    FeAl and Mo-Si-B intermetallic coatings for elevated temperature environmental resistance were prepared using high-velocity oxy-fuel (HVOF) and air plasma spray (APS) techniques. For both coating types, the effect of coating parameters (spray particle velocity and temperature) on the microstructure and physical properties of the coatings was assessed. Fe-24Al (wt.%) coatings were prepared using HVOF thermal spraying at spray particle velocities varying from 540 m/s to 700 m/s. Mo-13.4Si-2.6B coatings were prepared using APS at particle velocities of 180 and 350 m/s. Residual stresses in the HVOF FeAl coatings were compressive, while stresses in the APS Mo-Si-B coatings were tensile. In both cases, residual stresses became more compressive with increasing spray particle velocity due to increased peening imparted by the spray particles. The hardness and elastic moduli of FeAl coatings also increased with increasing particle velocity, again due to an increased peening effect. For Mo-Si-B coatings, plasma spraying at 180 m/s resulted in significant oxidation of the spray particles and conversion of the T1 phase into amorphous silica and {alpha}-Mo. The T1 phase was retained after spraying at 350 m/s.

  12. Surface oxidation energetics and kinetics on MoS{sub 2} monolayer

    SciTech Connect (OSTI)

    KC, Santosh; Longo, Roberto C.; Wallace, Robert M.; Cho, Kyeongjae

    2015-04-07

    In this work, surface oxidation of monolayer MoS{sub 2} (one of the representative semiconductors in transition-metal dichalcogenides) has been investigated using density functional theory method. Oxygen interaction with MoS{sub 2} shows that, thermodynamically, the surface tends to be oxidized. However, the dissociative absorption of molecular oxygen on the MoS{sub 2} surface is kinetically limited due to the large energy barrier at low temperature. This finding elucidates the air stability of MoS{sub 2} surface in the atmosphere. Furthermore, the presence of defects significantly alters the surface stability and adsorption mechanisms. The electronic properties of the oxidized surface have been examined as a function of oxygen adsorption and coverage as well as substitutional impurities. Our results on energetics and kinetics of oxygen interaction with the MoS{sub 2} monolayer are useful for the understanding of surface oxidation, air stability, and electronic properties of transition-metal dichalcogenides at the atomic scale.

  13. Elementary Steps of Syngas Reactions on Mo2C(001): Adsorption Thermochemistry and Bond Dissociation

    SciTech Connect (OSTI)

    Medford, Andrew

    2012-02-16

    Density functional theory (DFT) and ab initio thermodynamics are applied in order to investigate the most stable surface and subsurface terminations of Mo{sub 2}C(001) as a function of chemical potential and in the presence of syngas. The Mo-terminated (001) surface is then used as a model surface to evaluate the thermochemistry and energetic barriers for key elementary steps in syngas reactions. Adsorption energy scaling relations and Broensted-Evans-Polanyi relationships are established and used to place Mo{sub 2}C into the context of transition metal surfaces. The results indicate that the surface termination is a complex function of reaction conditions and kinetics. It is predicted that the surface will be covered by either C{sub 2}H{sub 2} or O depending on conditions. Comparisons to transition metals indicate that the Mo-terminated Mo{sub 2}C(001) surface exhibits carbon reactivity similar to transition metals such as Ru and Ir, but is significantly more reactive towards oxygen.

  14. TEM Characterization of High Burn-up Microstructure of U-7Mo Alloy

    SciTech Connect (OSTI)

    Jian Gan; Brandon Miller; Dennis Keiser; Adam Robinson; James Madden; Pavel Medvedev; Daniel Wachs

    2014-04-01

    As an essential part of global nuclear non-proliferation effort, the RERTR program is developing low enriched U-Mo fuels (< 20% U-235) for use in research and test reactors that currently employ highly enriched uranium fuels. One type of fuel being developed is a dispersion fuel plate comprised of U-7Mo particles dispersed in Al alloy matrix. Recent TEM characterizations of the ATR irradiated U-7Mo dispersion fuel plates include the samples with a local fission densities of 4.5, 5.2, 5.6 and 6.3 E+21 fissions/cm3 and irradiation temperatures of 101-136?C. The development of the irradiated microstructure of the U-7Mo fuel particles consists of fission gas bubble superlattice, large gas bubbles, solid fission product precipitates and their association to the large gas bubbles, grain subdivision to tens or hundreds of nanometer size, collapse of bubble superlattice, and amorphisation. This presentation will describe the observed microstructures specifically focusing on the U-7Mo fuel particles. The impact of the observed microstructure on the fuel performance and the comparison of the relevant features with that of the high burn-up UO2 fuels will be discussed.

  15. MvirDB: Microbial Database of Protein Toxins, Virulence Factors and Antibiotic Resistance Genes for Bio-Defense Applications

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

    Zhou, C. E.; Smith, J.; Lam, M.; Zemla, M. D.; Slezak, T.

    MvirDB is a cenntralized resource (data warehouse) comprising all publicly accessible, organized sequence data for protein toxins, virulence factors, and antibiotic resistance genes. Protein entries in MvirDB are annotated using a high-throughput, fully automated computational annotation system; annotations are updated periodically to ensure that results are derived using current public database and open-source tool releases. Tools provided for using MvirDB include a web-based browser tool and BLAST interfaces. MvirDB serves researchers in the bio-defense and medical fields. (taken from page 3 of PI's paper of same title published in Nucleic Acids Research, 2007, Vol.35, Database Issue (Open Source)

  16. Magnetic Interaction Reversal In Watermelon Nanostructured Cr-doped Fe Nanoclusters

    SciTech Connect (OSTI)

    Kaur, Maninder; Dai, Qilin; Bowden, Mark E.; Engelhard, Mark H.; Wu, Yaqiao; Tang, Jinke; Qiang, You

    2013-11-11

    Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (<10 at. %) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr2O3 and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (rv25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of r-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs. The giant magnetoresistance (GMR) effect,1,2 where an antiferromagnetic (AFM) exchange coupling exists between two ferromagnetic (FM) layers separated by a certain type of magnetic or non-magnetic spacer,3 has significant potential for application in the magnetic recording industry. Soon after the discovery of the GMR, the magnetic properties of multilayer systems (FeCr) became a subject of intensive study. The application of bulk iron-chromium (Fe-Cr) alloys has been of great interest, as these alloys exhibit favorable prop- erties including corrosion resistance, high strength, hardness, low oxidation rate, and strength retention at elevated temper- ature. However, the structural and magnetic properties of Cr-doped Fe nanoclusters (NCs) have not been investigated in-depth. Of all NCs, Fe-based clusters have unique magnetic properties as well as favorable catalytic characteristics in reactivity, selectivity, and durability.4 The incorporation of dopant of varied type and concentration in Fe can modify its chemical ordering, thereby optimizing its electrical, optical, and magnetic properties and opening up many new applications. The substitution of an Fe atom (1.24 A˚ ) by a Cr atom (1.25 A˚ ) can easily modify the magnetic properties, since (i) the curie temperature (Tc ) of Fe is 1043 K, while Cr is an itinerant AFM with a bulk Neel temperature TN =311 K, and (ii) Fe and Cr share the same crystal structure (bcc) with only 0.5% difference between their lattice constants.

  17. Improving thermostability of CrO{sub 2} thin films by doping with Sn

    SciTech Connect (OSTI)

    Ding, Yi; Wang, Ziyu; Liu, Shuo; Shi, Jing; Yin, Di; Yuan, Cheng; Lu, Zhihong; Xiong, Rui

    2014-09-01

    Chromium dioxide (CrO{sub 2}) is an ideal material for spin electronic devices since it has almost 100% spin polarization near Fermi level. However, it is thermally unstable and easily decomposes to Cr{sub 2}O{sub 3} even at room temperature. In this study, we try to improve the thermal stability of CrO{sub 2} thin films by doping with Sn whose oxide has the same structure as CrO{sub 2}. High quality epitaxial CrO{sub 2} and Sn-doped CrO{sub 2} films were grown on single crystalline TiO{sub 2} (100) substrates by chemical vapor deposition. Sn{sup 4+} ions were believed to be doped into CrO{sub 2} lattice and take the lattice positions of Cr{sup 4+}. The magnetic measurements show that Sn-doping leads to a decrease of magnetocrystalline anisotropy. The thermal stabilities of the films were evaluated by annealing the films at different temperatures. Sn-doped films can withstand a temperature up to 510 °C, significantly higher than what undoped films can do (lower than 435 °C), which suggests that Sn-doping indeed enhances the thermal stability of CrO{sub 2} films. Our study also indicates that Sn-doping may not change the essential half metallic properties of CrO{sub 2}. Therefore, Sn-doped CrO{sub 2} is expected to be very promising for applications in spintronic devices.

  18. Highly conducting SrMoO{sub 3} thin films for microwave applications

    SciTech Connect (OSTI)

    Radetinac, Aldin Mani, Arzhang; Ziegler, Jrgen; Alff, Lambert; Komissinskiy, Philipp; Melnyk, Sergiy; Nikfalazar, Mohammad; Zheng, Yuliang; Jakoby, Rolf

    2014-09-15

    We have measured the microwave resistance of highly conducting perovskite oxide SrMoO{sub 3} thin film coplanar waveguides. The epitaxial SrMoO{sub 3} thin films were grown by pulsed laser deposition and showed low mosaicity and smooth surfaces with a root mean square roughness below 0.3?nm. Layer-by-layer growth could be achieved for film thicknesses up to 400?nm as monitored by reflection high-energy electron diffraction and confirmed by X-ray diffraction. We obtained a constant microwave resistivity of 29???cm between 0.1 and 20?GHz by refining the frequency dependence of the transmission coefficients. Our result shows that SrMoO{sub 3} is a viable candidate as a highly conducting electrode material for all-oxide microwave electronic devices.

  19. Controlling the metal to semiconductor transition of MoS2 and WS2 in solution

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

    Chou, Stanley Shihyao; Yi-Kai Huang; Kim, Jaemyung; Kaehr, Bryan James; Foley, Brian M.; Lu, Ping; Conner Dykstra; Hopkins, Patrick E.; Brinker, C. Jeffrey; Jiaxing Huang; et al

    2015-01-22

    Lithiation-exfoliation produces single to few-layered MoS2 and WS2 sheets dispersible in water. However, the process transforms them from the pristine semiconducting 2H phase to a distorted metallic phase. Recovery of the semiconducting properties typically involves heating of the chemically exfoliated sheets at elevated temperatures. Therefore, it has been largely limited to sheets deposited on solid substrates. We report the dispersion of chemically exfoliated MoS2 sheets in high boiling point organic solvents enabled by surface functionalization and the controllable recovery of their semiconducting properties directly in solution. Ultimately, this process connects the scalability of chemical exfoliation with the simplicity of solutionmore » processing, enabling a facile method for tuning the metal to semiconductor transitions of MoS2 and WS2 within a liquid medium.« less

  20. Electronic and magnetic properties of Mo doped graphene; full potential approach

    SciTech Connect (OSTI)

    Thakur, Jyoti Kashyap, Manish K.; Singh, Mukhtiyar; Saini, Hardev S.

    2015-05-15

    The electronic and magnetic properties of Pristine and Mo doped Graphene have been calculated using WIEN2k implementation of full potential linearized augmented plane wave (FPLAPW) method based on Density Functional Theory (DFT). The exchange and correlation (XC) effects were taken into account by generalized gradient approximation (GGA). The calculated results show that Mo doping creates magnetism in Graphene by shifting the energy levels at E{sub F} and opens up a channel for Graphene to be used in real nanoscale device applications. The unpaired d-electrons of Mo atom are responsible for induced magnetism in Graphene. Magnetic ordering created in Graphene in this way makes it suitable for recording media, magnetic sensors, magnetic inks and spintronic devices.

  1. Exciton-dominant electroluminescence from a diode of monolayer MoS{sub 2}

    SciTech Connect (OSTI)

    Ye, Yu; Ye, Ziliang; Gharghi, Majid; Zhu, Hanyu; Wang, Yuan; Zhao, Mervin; Yin, Xiaobo; Zhang, Xiang

    2014-05-12

    In two-dimensional monolayer MoS{sub 2}, excitons dominate the absorption and emission properties. However, the low electroluminescent efficiency and signal-to-noise ratio limit our understanding of the excitonic behavior of electroluminescence. Here, we study the microscopic origin of the electroluminescence from a diode of monolayer MoS{sub 2} fabricated on a heavily p-type doped silicon substrate. Direct and bound-exciton related recombination processes are identified from the electroluminescence. At a high electron-hole pair injection rate, Auger recombination of the exciton-exciton annihilation of the bound exciton emission is observed at room temperature. Moreover, the efficient electrical injection demonstrated here allows for the observation of a higher energy exciton peak of 2.255?eV in the monolayer MoS{sub 2} diode, attributed to the excited exciton state of a direct-exciton transition.

  2. Observation of localized states in atomically thin MoS{sub 2} field effect transistor

    SciTech Connect (OSTI)

    Ghatak, Subhamoy; Pal, Atindra Nath; Ghosh, Arindam

    2013-12-04

    We present electrical transport and low frequency (1/f) noise measurements on mechanically exfoliated single, bi and trilayer MoS{sub 2}-based FET devices on Si/SiO{sub 2} substrate. We find that the electronic states in MoS{sub 2} are localized at low temperatures (T) and conduction happens through variable range hopping (VRH). A steep increase of 1/f noise with decreasing T, typical for localized regime was observed in all of our devices. From gate voltage dependence of noise, we find that the noise power is inversely proportional to square of the number density (? 1/n{sup 2}) for a wide range of T, indicating number density fluctuations to be the dominant source of 1/f noise in these MoS{sub 2} FETs.

  3. Thermal stability of fission gas bubble superlattice in irradiated U10Mo fuel

    SciTech Connect (OSTI)

    Gan, J.; Keiser, D. D.; Miller, B. D.; Robinson, A. B.; Wachs, D. M.; Meyer, M. K.

    2015-09-01

    To investigate the thermal stability of the fission gas bubble superlattice, a key microstructural feature in both irradiated U-7Mo dispersion and U-10Mo monolithic fuel plates, a FIB-TEM sample of the irradiated U-10Mo fuel with a local fission density of 3.51021 fissions/cm3 was used for an in-situ heating TEM experiment. The temperature of the heating holder was raised at a ramp rate of approximately 10 C/min up to ~700 C, kept at that temperature for about 34 min, continued to 850 C with a reduced rate of 5 C/min. The result shows a high thermal stability of the fission gas bubble superlattice. The implication of this observation on the fuel microstructural evolution and performance under irradiation is discussed.

  4. Two-step growth of two-dimensional WSe2/MoSe2 heterostructures

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

    Gong, Yongji; Lei, Sidong; Lou, Jun; Liu, Zheng; Vajtai, Robert; Zhou, Wu; Ajayan, Pullikel M.

    2015-08-03

    Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe2 was synthesized first and followed by an epitaxial growth of WSe2 on the edge and on the top surface of MoSe2. Compared to previously reported one-step growth methods, thismore » two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 μm) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe2/MoSe2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe2/WSe2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe2/MoSe2 bilayer and the exposed MoSe2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. As a result, a photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting.« less

  5. SEM and TEM Characterization of As-Fabricated U-7Mo Disperson Fuel Plates

    SciTech Connect (OSTI)

    D. D. Keiser, Jr.; B. Yao; E. Perez; Y. H. Sohn

    2009-11-01

    The starting microstructure of a dispersion fuel plate can have a dramatic impact on the overall performance of the plate during irradiation. To improve the understanding of the as-fabricated microstructures of dispersion fuel plates, SEM and TEM analysis have been performed on RERTR-9A archive fuel plates, which went through an additional hot isostatic procsssing (HIP) step during fabrication. The fuel plates had depleted U-7Mo fuel particles dispersed in either Al-2Si or 4043 Al alloy matrix. For the characterized samples, it was observed that a large fraction of the ?-phase U-7Mo alloy particles had decomposed during fabrication, and in areas near the fuel/matrix interface where the transformation products were present significant fuel/matrix interaction had occurred. Relatively thin Si-rich interaction layers were also observed around the U-7Mo particles. In the thick interaction layers, (U)(Al,Si)3 and U6Mo4Al43 were identified, and in the thin interaction layers U(Al,Si)3, U3Si3Al2, U3Si5, and USi1.88-type phases were observed. The U3Si3Al2 phase contained some Mo. Based on the results of this work, exposure of dispersion fuel plates to relatively high temperatures during fabrication impacts the overall microstructure, particularly the nature of the interaction layers around the fuel particles. The time and temperature of fabrication should be carefully controlled in order to produce the most uniform Si-rich layers around the U-7Mo particles.

  6. Electrical and photovoltaic characteristics of MoS{sub 2}/Si p-n junctions

    SciTech Connect (OSTI)

    Hao, Lanzhong Liu, Yunjie Gao, Wei; Han, Zhide; Xue, Qingzhong; Zeng, Huizhong; Wu, Zhipeng; Zhu, Jun; Zhang, Wanli

    2015-03-21

    Bulk-like molybdenum disulfide (MoS{sub 2}) thin films were deposited on the surface of p-type Si substrates using dc magnetron sputtering technique and MoS{sub 2}/Si p-n junctions were formed. The vibrating modes of E{sup 1}{sub 2g} and A{sub 1g} were observed from the Raman spectrum of the MoS{sub 2} films. The current density versus voltage (J-V) characteristics of the junction were investigated. A typical J-V rectifying effect with a turn-on voltage of 0.2?V was shown. In different voltage range, the electrical transporting of the junction was dominated by diffusion current and recombination current, respectively. Under the light illumination of 15?mW?cm{sup ?2}, the p-n junction exhibited obvious photovoltaic characteristics with a short-circuit current density of 3.2?mA?cm{sup ?2} and open-circuit voltage of 0.14?V. The fill factor and energy conversion efficiency were 42.4% and 1.3%, respectively. According to the determination of the Fermi-energy level (?4.65?eV) and energy-band gap (?1.45?eV) of the MoS{sub 2} films by capacitance-voltage curve and ultraviolet-visible transmission spectra, the mechanisms of the electrical and photovoltaic characteristics were discussed in terms of the energy-band structure of the MoS{sub 2}/Si p-n junctions. The results hold the promise for the integration of MoS{sub 2} thin films with commercially available Si-based electronics in high-efficient photovoltaic devices.

  7. Primary arm spacing in chill block melt spun Ni-Mo alloys

    SciTech Connect (OSTI)

    Tewari, S.N.; Glasgow, T.K.

    1986-01-01

    Chill block melt spun ribbons of Ni-Mo binary alloys containing 8.0 to 41.8 wt % Mo have been prepared under carefully controlled processing conditions. The growth velocity has been determined as a function of distance from the quench surface from the observed ribbon thickness dependence on the melt puddle residence time. Primary arm spacings measured at the midribbon thickness locations show a dependence on growth velocity and alloy composition which is expected from dendritic growth models for binary alloys directionally solidified in a positive temperature gradient.

  8. Neutrino-nucleus scattering of {sup 95,97}Mo and {sup 116}Cd

    SciTech Connect (OSTI)

    Ydrefors, E.; Almosly, W.; Suhonen, J.

    2013-12-30

    Accurate knowledge about the nuclear responses to supernova neutrinos for relevant nuclear targets is important both for neutrino detection and for astrophysical applications. In this paper we discuss the cross sections for the charged-current neutrino-nucleus scatterings off {sup 95,97}Mo and {sup 116}Cd. The microscopic quasiparticle-phonon model is adopted for the odd-even nuclei {sup 95,97}Mo. In the case of {sup 116}Cd we present cross sections both for the Bonn one-boson-exchange potential and self-consistent calculations based on modern Skyrme interactions.

  9. Site-dependent free energy barrier for proton reduction on MoS2 edges

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Site-dependent free energy barrier for proton reduction on MoS2 edges Citation Details In-Document Search Title: Site-dependent free energy barrier for proton reduction on MoS2 edges Authors: Choi, W ; Wood, B C ; Schwegler, E ; Ogitsu, T Publication Date: 2013-05-30 OSTI Identifier: 1113397 Report Number(s): LLNL-JRNL-639087 DOE Contract Number: W-7405-ENG-48 Resource Type: Journal Article Resource Relation: Journal Name: Journal of Physical Chemistry C,

  10. Structure and Electronic Properties of MoVO type Mixed-metal Oxides ¿ a

    Office of Scientific and Technical Information (OSTI)

    Combined View by Experiment and Theory (Journal Article) | SciTech Connect Structure and Electronic Properties of MoVO type Mixed-metal Oxides ¿ a Combined View by Experiment and Theory Citation Details In-Document Search Title: Structure and Electronic Properties of MoVO type Mixed-metal Oxides ¿ a Combined View by Experiment and Theory Authors: Chiu, C ; Vogt, T ; Zhao, L ; Genest, A ; Rosch, N Publication Date: 2015-07-01 OSTI Identifier: 1229398 Report Number(s): BNL--111474-2015-JA

  11. Surface confined quantum well state in MoS{sub 2}(0001) thin film (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Surface confined quantum well state in MoS{sub 2}(0001) thin film Citation Details In-Document Search Title: Surface confined quantum well state in MoS{sub 2}(0001) thin film Surface confined quantum well state (scQWS) is a QWS confined around the surface of a thin film whose electronic energy is smaller than the work function of the film. The scQWS is rather rare in most thin films. Here, we show the existence of scQWS in thin films of transition metal

  12. Thickness-dependent charge transport in few-layer MoS 2 field-effect

    Office of Scientific and Technical Information (OSTI)

    transistors (Journal Article) | SciTech Connect Thickness-dependent charge transport in few-layer MoS 2 field-effect transistors Citation Details In-Document Search This content will become publicly available on March 10, 2017 Title: Thickness-dependent charge transport in few-layer MoS 2 field-effect transistors Authors: Lin, Ming-Wei ; Kravchenko, Ivan I. ; Fowlkes, Jason ; Li, Xufan ; Puretzky, Alexander A. ; Rouleau, Christopher M. ; Geohegan, David B. ; Xiao, Kai Publication Date:

  13. Metastable bcc phase formation in the Nb-Cr-Ti system

    SciTech Connect (OSTI)

    Thoma, D.J.; Perepezko, J.H.

    1994-08-01

    Metastable disordered bcc phases have been formed from the melt in the Nb-Cr-Ti system where primary Laves phases would develop under equilibrium solidification conditions. Three vertical temperature-composition sections in the ternary system incorporating NbCr, were evaluated: the Nb-Cr binary, the TiCr{sub 2}-NbCr{sub 2} isoplethal section, and the NbCr{sub 2}-Ti plethal section. In the rapid solidification of NbCr{sub 2}, metastable bcc phase formation was not observed, but deviations from NbCr{sub 2} stoichiometry or alloying with Ti was found to promote bcc phase formation by decreasing the required liquid undercooling to reach the metastable bcc liquidus and solidus. The metastable phases were characterized through x-ray diffraction (XRD), and systematic deviations from Vegard`s Rule have been defined in the three plethal sections. The metastable bcc phases decompose at temperatures >800{degrees}C to uniformly refined microstructures. As a result, novel microstructural tailoring schemes are possible through the metastable precursor microstructures.

  14. Audit Report: CR-B-95-06 | Department of Energy

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

    5-06 Audit Report: CR-B-95-06 June 30, 1995 Audit of Department of Energy Support Service Contracting PDF icon Audit Report: CR-B-95-06 More Documents & Publications Audit Report: IG-0427 Inspection Report: IG-0377 Chapter 16 - Types of Contracts

  15. Audit Report: CR-FS-96-03 | Department of Energy

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

    6-03 Audit Report: CR-FS-96-03 April 15, 1996 Report on Matters Identified at Strategic Petroleum Reserve During Audit of Statement of Financial Position PDF icon Audit Report: CR-FS-96-03 More Documents & Publications Audit Report: IG-0370 Inspection Report: INS-9502 Audit Report: ER-FS-99-04

  16. Audit Report: CR-B-95-02 | Department of Energy

    Energy Savers [EERE]

    5-02 Audit Report: CR-B-95-02 November 10, 1994 Audit of Management Controls Over Selected Energy Research Major System Acquisitions PDF icon Audit Report: CR-B-95-02 More Documents & Publications Audit Report: ER-B-95-04 Audit Report: IG-0389 Audit Report: IG-0543

  17. Persistent photoconductivity in two-dimensional Mo1-xW xSe2–MoSe2 van der Waals heterojunctions

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

    Puretzky, Alexander A.; Basile, Leonardo; Idrobo, Juan Carlos; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai; Li, Xufan; Lin, Ming -Wei; Wang, Kei

    2016-02-16

    Van der Waals (vdW) heterojunctions consisting of vertically-stacked individual or multiple layers of two-dimensional (2D) layered semiconductors, especially the transition metal dichalcogenides (TMDs), are fascinating new artificial solids just nanometers-thin that promise novel optoelectronic functionalities due to the sensitivity of their electronic and optical properties to strong quantum confinement and interfacial interactions. Here, monolayers of n-type MoSe2 and p-type Mo1-xW xSe2–MoSe2 are grown by vapor transport methods, then transferred and stamped to form artificial vdW heterostructures with different interlayer orientations. Atomic-resolution Z-contrast electron microscopy and electron diffraction are used to characterize both the individual monolayers and the atomic registry betweenmore » layers in the bilayer vdW heterostructures. These measurements are compared with photoluminescence and low-frequency Raman spectroscopy, which indicates strong interlayer coupling in heterostructures. Remarkably, the heterojunctions exhibit an unprecedented photoconductivity effect that persists at room temperature for several days. This persistent photoconductivity is shown to be tunable by applying a gate bias that equilibrates the charge distribution. Furthermore, these measurements indicate that such ultrathin vdW heterojunctions can function as rewritable optoelectronic switches or memory elements under time-dependent photo-illumination, an effect which appears promising for new monolayer TMDs-based optoelectronic devices applications.« less

  18. NEUTRON-INDUCED SWELLING OF Fe-Cr BINARY ALLOYS IN FFTF AT ~400 DEGREES C

    SciTech Connect (OSTI)

    Garner, Francis A.; Greenwood, Lawrence R.; Okita, Taira; Sekimura, Naoto; Wolfer, W. G.

    2002-12-31

    The purpose of this effort is to determine the influence of dpa rate, He/dpa ratio and composition on the void swelling of simple binary Fe-Cr alloys. Contrary to the behavior of swelling of model fcc Fe-Cr-Ni alloys irradiated in the same FFTF-MOTA experiment, model bcc Fe-Cr alloys do not exhibit a dependence of swelling on dpa rate at approximately 400 degrees C. This is surprising in that an apparent flux-sensitivity was observed in an earlier comparative irradiation of Fe-Cr binaries conducted in EBR-II and FFTF. The difference in behavior is ascribed to the higher helium generation rates of Fe-Cr alloys in EBR-II compared to that of FFTF, and also the fact that lower dpa rates in FFTF are accompanied by progressively lower helium generation rates.

  19. Single-layer MoS{sub 2} roughness and sliding friction quenching by interaction with atomically flat substrates

    SciTech Connect (OSTI)

    Quereda, J.; Castellanos-Gomez, A.; Agrat, N.; Rubio-Bollinger, G.

    2014-08-04

    We experimentally study the surface roughness and the lateral friction force in single-layer MoS{sub 2} crystals deposited on different substrates: SiO{sub 2}, mica, and hexagonal boron nitride (h-BN). Roughness and sliding friction measurements are performed by atomic force microscopy. We find a strong dependence of the MoS{sub 2} roughness on the underlying substrate material, being h-BN the substrate which better preserves the flatness of the MoS{sub 2} crystal. The lateral friction also lowers as the roughness decreases, and attains its lowest value for MoS{sub 2} flakes on h-BN substrates. However, it is still higher than for the surface of a bulk MoS{sub 2} crystal, which we attribute to the deformation of the flake due to competing tip-to-flake and flake-to-substrate interactions.

  20. High blue-near ultraviolet photodiode response of vertically stacked graphene-MoS{sub 2}-metal heterostructures

    SciTech Connect (OSTI)

    Wi, Sungjin; Chen, Mikai; Nam, Hongsuk; Liu, Amy C.; Meyhofer, Edgar; Liang, Xiaogan

    2014-06-09

    We present a study on the photodiode response of vertically stacked graphene/MoS{sub 2}/metal heterostructures in which MoS{sub 2} layers are doped with various plasma species. In comparison with undoped heterostructures, such doped ones exhibit significantly improved quantum efficiencies in both photovoltaic and photoconductive modes. This indicates that plasma-doping-induced built-in potentials play an important role in photocurrent generation. As compared to indium-tin-oxide/ MoS{sub 2}/metal structures, the presented graphene/MoS{sub 2}/metal heterostructures exhibit greatly enhanced quantum efficiencies in the blue-near ultraviolet region, which is attributed to the low density of recombination centers at graphene/MoS{sub 2} heterojunctions. This work advances the knowledge for making photo-response devices based on layered materials.

  1. Effect of mechanical strain on electronic properties of bulk MoS{sub 2}

    SciTech Connect (OSTI)

    Kumar, Sandeep Kumar, Jagdish Sastri, O. S. K. S.

    2015-05-15

    Ab-initio density functional theory based calculations of electronic properties of bulk and monolayer Molybdenum di-Sulfide (MoS{sub 2}) have been performed using all electron Full Potential Linearised Augmentad Plane Wave (FPLAPW) method using Elk code. We have used Generalised Gradient Approximation (GGA) for exchange and correlation functionals and performed calculaitons of Lattice parameters, Density Of States (DOS) and Band Structure (BS). Band structure calculations revealed that bulk MoS{sub 2} has indirect band gap of 0.97 eV and mono-layer MoS{sub 2} has direct band gap which has increased to 1.71 eV. These are in better agreement with experimental values as compared with the other calculations using pseudo-potential code. The effect of mechanical strain on the electronic properties of bulk MoS{sub 2} has also been studied. For the different values of compressive strain (varying from 2% to 8% in steps of 2%) along the c-axis, the corresponding DOS and BS are obtained. We observed that the band gap decreases by about 15% for every 2% increase in strain along the c-axis.

  2. EIS-0475: Disposition of the Bannister Federal Complex, Kansas City, MO

    Broader source: Energy.gov [DOE]

    NNSA/DOE announces its intent to prepare an EIS for the disposition of the Bannister Federal Complex, Kansas City, MO. NNSA previously decided in a separate NEPA review (EA-1592) to relocate its operations from the Bannister Federal Complex to a newly constructed industrial campus eight miles from the current location.

  3. On the combined gradient-stochastic plasticity model: Application to Mo-micropillar compression

    SciTech Connect (OSTI)

    Konstantinidis, A. A.; Zhang, X.; Aifantis, E. C.

    2015-02-17

    A formulation for addressing heterogeneous material deformation is proposed. It is based on the use of a stochasticity-enhanced gradient plasticity model implemented through a cellular automaton. The specific application is on Mo-micropillar compression, for which the irregularities of the strain bursts observed have been experimentally measured and theoretically interpreted through Tsallis' q-statistics.

  4. Electric contributions to magnetic force microscopy response from graphene and MoS{sub 2} nanosheets

    SciTech Connect (OSTI)

    Li, Lu Hua Chen, Ying

    2014-12-07

    Magnetic force microscopy (MFM) signals have recently been detected from whole pieces of mechanically exfoliated graphene and molybdenum disulfide (MoS{sub 2}) nanosheets, and magnetism of the two nanomaterials was claimed based on these observations. However, non-magnetic interactions or artefacts are commonly associated with MFM signals, which make the interpretation of MFM signals not straightforward. A systematic investigation has been done to examine possible sources of the MFM signals from graphene and MoS{sub 2} nanosheets and whether the MFM signals can be correlated with magnetism. It is found that the MFM signals have significant non-magnetic contributions due to capacitive and electrostatic interactions between the nanosheets and conductive cantilever tip, as demonstrated by electric force microscopy and scanning Kevin probe microscopy analyses. In addition, the MFM signals of graphene and MoS{sub 2} nanosheets are not responsive to reversed magnetic field of the magnetic cantilever tip. Therefore, the observed MFM response is mainly from electric artefacts and not compelling enough to correlate with magnetism of graphene and MoS{sub 2} nanosheets.

  5. Equation of state of bcc-Mo by static volume compression to 410 GPa

    SciTech Connect (OSTI)

    Akahama, Yuichi; Hirao, Naohisa; Ohishi, Yasuo; Singh, Anil K.

    2014-12-14

    Unit cell volumes of Mo and Pt have been measured simultaneously to ≈400 GPa by x-ray powder diffraction using a diamond anvil cell and synchrotron radiation source. The body-centered cubic (bcc) phase of Mo was found to be stable up to 410 GPa. The equation of state (EOS) of bcc-Mo was determined on the basis of Pt pressure scale. A fit of Vinet EOS to the volume compression data gave K{sub 0} = 262.3(4.6) GPa, K{sub 0}′ = 4.55(16) with one atmosphere atomic volume V{sub 0} = 31.155(24) A{sup 3}. The EOS was in good agreement with the previous ultrasonic data within pressure difference of 2.5%–3.3% in the multimegabar range, though the EOS of Mo proposed from a shock compression experiment gave lower pressure by 7.2%–11.3% than the present EOS. The agreement would suggest that the Pt pressure scale provides an accurate pressure value in an ultra-high pressure range.

  6. MoS{sub 2} functionalization for ultra-thin atomic layer deposited dielectrics

    SciTech Connect (OSTI)

    Azcatl, Angelica; McDonnell, Stephen; Santosh, K.C.; Peng, Xin; Dong, Hong; Qin, Xiaoye; Addou, Rafik; Lu, Ning; Kim, Moon J.; Cho, Kyeongjae; Wallace, Robert M.; Mordi, Greg I.; Kim, Jiyoung

    2014-03-17

    The effect of room temperature ultraviolet-ozone (UV-O{sub 3}) exposure of MoS{sub 2} on the uniformity of subsequent atomic layer deposition of Al{sub 2}O{sub 3} is investigated. It is found that a UV-O{sub 3} pre-treatment removes adsorbed carbon contamination from the MoS{sub 2} surface and also functionalizes the MoS{sub 2} surface through the formation of a weak sulfur-oxygen bond without any evidence of molybdenum-sulfur bond disruption. This is supported by first principles density functional theory calculations which show that oxygen bonded to a surface sulfur atom while the sulfur is simultaneously back-bonded to three molybdenum atoms is a thermodynamically favorable configuration. The adsorbed oxygen increases the reactivity of MoS{sub 2} surface and provides nucleation sites for atomic layer deposition of Al{sub 2}O{sub 3}. The enhanced nucleation is found to be dependent on the thin film deposition temperature.

  7. 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

  8. M&O Contract 2008-2013, Alliance for Sustainable Energy, LLC

    Broader source: Energy.gov [DOE]

    Contract No. DE-AC36-08GO28308 M&O Contract 2008-2013, between the Alliance for Sustainable Energy, LLC and the U.S. Department Of Energy. Part I, Section B, Supplies and Services and Price/Costs.

  9. Development of ODS FeCrAl alloys for accident-tolerant fuel cladding

    SciTech Connect (OSTI)

    Dryepondt, Sebastien N.; Hoelzer, David T.; Pint, Bruce A.; Unocic, Kinga A.

    2015-09-18

    FeCrAl alloys are prime candidates for accident-tolerant fuel cladding due to their excellent oxidation resistance up to 1400 C and good mechanical properties at intermediate temperature. Former commercial oxide dispersion strengthened (ODS) FeCrAl alloys such as PM2000 exhibit significantly better tensile strength than wrought FeCrAl alloys, which would alloy for the fabrication of a very thin (~250 m) ODS FeCrAl cladding and limit the neutronic penalty from the replacement of Zr-based alloys by Fe-based alloys. Several Fe-12-Cr-5Al ODS alloys where therefore fabricated by ball milling FeCrAl powders with Y2O3 and additional oxides such as TiO2 or ZrO2. The new Fe-12Cr-5Al ODS alloys showed excellent tensile strength up to 800 C but limited ductility. Good oxidation resistance in steam at 1200 and 1400 C was observed except for one ODS FeCrAl alloy containing Ti. Rolling trials were conducted at 300, 600 C and 800 C to simulate the fabrication of thin tube cladding and a plate thickness of ~0.6mm was reached before the formation of multiple edge cracks. Hardness measurements at different stages of the rolling process, before and after annealing for 1h at 1000 C, showed that a thinner plate thickness could likely be achieved by using a multi-step approach combining warm rolling and high temperature annealing. Finally, new Fe-10-12Cr-5.5-6Al-Z gas atomized powders have been purchased to fabricate the second generation of low-Cr ODS FeCrAl alloys. The main goals are to assess the effect of O, C, N and Zr contents on the ODS FeCrAl microstructure and mechanical properties, and to optimize the fabrication process to improve the ductility of the 2nd gen ODS FeCrAl while maintaining good mechanical strength and oxidation resistance.

  10. Interaction Layer Characteristics in U-xMo Dispersion/Monolithic Fuels

    SciTech Connect (OSTI)

    D. L. Porter

    2010-11-01

    Published data concerning the interaction layer (IL) formed between U-xMo fuel alloy and aluminum (Al)-based matrix or cladding materials was reviewed, including the effects of silicon (Si) content in the matrix/cladding, molybdenum (Mo) content in the fuel, pre irradiation thermal treatments, irradiation, and test temperature. The review revealed that tests conducted in the laboratory produce results different from those conducted in an irradiation environment. However, the laboratory testing relates well to thermal treatments performed prior to irradiation and helps in understanding the effects that these pre irradiation treatments have on in reactor performance. A pre-formed, Si-enriched IL seems to be important in delaying the onset of rapid growth of fission gas bubbles at low irradaiiation temperatures. Several other conclusions can be drawn: 1. An IL with phases akin to UAl3 is desired for optimum fuel performance, but at low temperatures, and especially in an irradiation atmosphere, the desired (Al+Si)/(U+Mo) ratio of three is difficult to produce. When the fuel operating temperature is low, it is important to create a pre-irradiation IL, enriched in Si. This pre-formed IL is relatively stable, performs well in terms of swelling resistance, and prevents rapid IL growth during irradiation. 2. At higher operating temperatures (>150–170°C), IL formation in reactor may not be so dependent on pre-irradiation IL formation, especially at high burnup; a pre-fabricated IL seems to be less stable at high burnup and high operating temperature. Moreover, the (Al+SI)/(U+Mo) ratio of three occurs more often at higher temperature. For these two reasons, it is important at high operating temperature to also have a matrix with significant Si content to create an IL in reactor with the right characteristics. 3. Out-of-reactor testing seems to indicate that Si in the matrix material is required in some concentration (2%, 5%, ?) to provide for a thin, Si-enriched IL formed before irradiation of a fuel plate. It ensures that the IL contains beneficial phases, or prevents formation of some known to promote poor fuel performance. Significant progress has been made in determining the desired characteristics of the IL. 4. The use of a fuel with stable gamma phase appears to allow more predictable performance regarding both a beneficial pre-irradiation layer, and the fuel performance (low swelling) to high burnup. Destabilization of the gamma phase may create problems with IL breakaway growth. 5. A theory whereby prevention of the U6Mo4Al43 complex phase in interaction layers formed during fabrication may be a key to good irradiation performance. Si additions to the matrix allow for solubility of Mo in the desirable (U,Mo)(Al,Si)3 or perhaps (U,Mo)(Al,Si)4 phase, helping to prevent formation of the complex phase. Keeping alloy Mo content as low as possible may also help so long as decomposition does not occur in fabrication, forcing Mo into the interaction layer. This theory may explain a number of apparent anomalies observed in testing results. 6. More work is needed in order to prescribe the conditions to best produce a beneficial IL. Another necessity is a better understanding of any correlation between beneficial characteristics of the pre-fabricated IL and the irradiation conditions to which it will be subjected.

  11. Progress in the material development of LiCaAlF sub 6 :Cr sup 3+ laser crystals

    SciTech Connect (OSTI)

    Michelle D. Shinn.; Chase, L.L.; Caird, J.A.; Payne, S.A.; Atherton, L.J.; Kway, W.L.

    1990-03-01

    High Cr{sup 3+} doping levels, up to 8 mole percent, and low losses have been obtained with the tunable solid-state laser material LiCaAlF{sub 6}:Cr{sup 3+} (Cr:LiCAF). Measurements and calculations show that high pumping and extraction efficiencies are possible with the improved material. 13 refs., 4 figs., 1 tab.

  12. Novel Processing of mo-si-b Intermetallics for improved efficiency of power systems

    SciTech Connect (OSTI)

    M.J. Kramer; O. Degirmen; A.J. Thom; M. Akinc

    2004-09-30

    Multiphase composite alloys based on the Mo-Si-B system are candidate materials for ultra-high temperature applications. In non load-bearing applications such as thermal barrier coatings or heat exchangers in fossil fuel burners, these materials may be ideally suited. Alloys based on the Mo{sub 5}Si{sub 3}B{sub x} phase (Tl phase) possess excellent oxidation resistance to at least 1600 C in synthetic air atmospheres. However, the ability of Tl-based alloys to resist aggressive combustion environments has not yet been determined. The present work seeks to investigate the resistance of these Mo-Si-B alloys to simulated combustion atmospheres. Material was pre-alloyed by combustion synthesis, and samples for testing were prepared by classic powder metallurgical processing techniques. Precursor material synthesized by self-heating-synthesis was sintered to densities exceeding 98% in an argon atmosphere at 1800 C. The approximate phase assemblage of the material was 57% Tl, 29% MoB, 14% MoSi{sub 2} (wt%). The alloy was oxidized from 1000-1100 C in flowing air containing water vapor at 18 Torr. At 1000 C the material achieved a steady state mass loss, and at 1100 C the material undergoes a steady state mass gain. The oxidation rate of these alloys in this temperature regime was accelerated by the presence of water vapor compared to oxidation in dry air. The results of microstructural analysis of the tested alloys will be discussed. Techniques and preliminary results for fabricating near-net-shaped parts will also be presented.

  13. Modeling of Interaction Layer Growth Between U-Mo Particles and an Al Matrix

    SciTech Connect (OSTI)

    Yeon Soo Kim; G. L. Hofman; Ho Jin Ryu; Jong Man Park; A. B. Robinson; D. M. Wachs

    2013-12-01

    Interaction layer growth between U-Mo alloy fuel particles and Al in a dispersion fuel is a concern due to the volume expansion and other unfavorable irradiation behavior of the interaction product. To reduce interaction layer (IL) growth, a small amount of Si is added to the Al. As a result, IL growth is affected by the Si content in the Al matrix. In order to predict IL growth during fabrication and irradiation, empirical models were developed. For IL growth prediction during fabrication and any follow-on heating process before irradiation, out-of-pile heating test data were used to develop kinetic correlations. Two out-of-pile correlations, one for the pure Al matrix and the other for the Al matrix with Si addition, respectively, were developed, which are Arrhenius equations that include temperature and time. For IL growth predictions during irradiation, the out-of-pile correlations were modified to include a fission-rate term to consider fission enhanced diffusion, and multiplication factors to incorporate the Si addition effect and the effect of the Mo content. The in-pile correlation is applicable for a pure Al matrix and an Al matrix with the Si content up to 8 wt%, for fuel temperatures up to 200 degrees C, and for Mo content in the range of 6 10wt%. In order to cover these ranges, in-pile data were included in modeling from various tests, such as the US RERTR-4, -5, -6, -7 and -9 tests and Koreas KOMO-4 test, that were designed to systematically examine the effects of the fission rate, temperature, Si content in Al matrix, and Mo content in U-Mo particles. A model converting the IL thickness to the IL volume fraction in the meat was also developed.

  14. Magnetic properties and hyperfine interactions in Cr{sub 8}, Cr{sub 7}Cd, and Cr{sub 7}Ni molecular rings from {sup 19}F-NMR

    SciTech Connect (OSTI)

    Bordonali, L.; Borsa, F.; Consorzio INSTM, Via Giusti 9, I-50121 Firenze; Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, Iowa 50011 ; Garlatti, E.; Dipartimento di Fisica e Scienze della Terra, Università di Parma, Viale G. P. Usberti 7 Casadei, C. M.; Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, Iowa 50011 ; Furukawa, Y.; Lascialfari, A.; Consorzio INSTM, Via Giusti 9, I-50121 Firenze; Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano ; Carretta, S.; Timco, G.; Winpenny, R. E. P.

    2014-04-14

    A detailed experimental investigation of the {sup 19}F nuclear magnetic resonance is made on single crystals of the homometallic Cr{sub 8} antiferromagnetic molecular ring and heterometallic Cr{sub 7}Cd and Cr{sub 7}Ni rings in the low temperature ground state. Since the F{sup −} ion is located midway between neighboring magnetic metal ions in the ring, the {sup 19}F-NMR spectra yield information about the local electronic spin density and {sup 19}F hyperfine interactions. In Cr{sub 8}, where the ground state is a singlet with total spin S{sub T} = 0, the {sup 19}F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the {sup 19}F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state S{sub T} = 1. In the heterometallic rings, Cr{sub 7}Cd and Cr{sub 7}Ni, whose ground state is magnetic with S{sub T} = 3/2 and S{sub T} = 1/2, respectively, the {sup 19}F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the {sup 19}F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F{sup −}-Ni{sup 2+} and the F{sup −}-Cd{sup 2+} bonds. The values of the hyperfine constants compare well to the ones known for F{sup −}-Ni{sup 2+} in KNiF{sub 3} and NiF{sub 2} and for F{sup −}-Cr{sup 3+} in K{sub 2}NaCrF{sub 6}. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F{sup −} ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  15. Probe Mssbauer spectroscopy of mechanical alloying in binary Cr?{sup 57}Fe(1 at%) system

    SciTech Connect (OSTI)

    Elsukov, Evgeny P. Kolodkin, Denis A. Ul'yanov, Alexander L. Porsev, Vitaly E.

    2014-10-27

    Solid state reactions during mechanical alloying (MA) in a binary mixture of powdered Cr and {sup 57}Fe in atomic ratio of 99:1 have been studied using {sup 57}Fe Mssbauer spectroscopy, X-ray diffraction and Auger spectrometry. The proposed model of MA includes formation of Cr(Fe){sub x}O{sub y} oxides at the contact places of Cr and Fe particles, formation of nanostructure with simultaneous dissolution of the oxides, penetration of Fe atoms along grain boundaries in close-to-boundary distorted zones of interfaces in a substitutional position, formation of the substitutional solid solution of Fe in Cr in the body of grains. It was shown that the increase in the BCC lattice parameter on increasing the milling time is due to the dissolution of oxides and formation of interstitial solid solution of O in Cr. There were established substantial differences in consumption of BCC Fe in a Mg ? Al ? Si ? Cr sequence due to the major role of chemical interaction of Mg(Al,Si,Cr) with Fe.

  16. Effects of competing magnetic interactions on the electronic transport properties of CuCrSe{sub 2}

    SciTech Connect (OSTI)

    Tewari, Girish C.; Jawaharlal Nehru University, New Delhi 110067 ; Karppinen, Maarit; Rastogi, Ashok K.

    2013-02-15

    We have synthesized single-phase samples of the CuCrSe{sub 2} phase that exhibits hexagonal-rhombohedral layered crystal structure with space group R3m. Here we present a detailed study of electronic transport and magnetic properties of CuCrSe{sub 2}. We moreover investigate the heat capacity of CuCrSe{sub 2} in comparison to that of CuCrS{sub 2}. The electrical resistivity of CuCrSe{sub 2} shows metallic-like behavior down to 2 K, while the thermoelectric power is large around 100 {mu}V K{sup -1} at 300 K. A weak anomaly in resistivity and a rounded maximum in magnetic susceptibility are observed around 55 K. No sharp transition at 55 K is observed in the heat capacity of CuCrSe{sub 2}, rather a visible maximum is seen. At low temperatures from 2 to 14 K, the magnetic heat capacity follows T{sup 2}-dependence. We tentatively believe this behavior of CuCrSe{sub 2} to be due to competing magnetic interactions between intralayer Cr atoms. The ferromagnetic Cr-Se-Cr indirect exchange among intralayer Cr atoms is enhanced in the selenide compound (that is more metallic than the sulfide compound), and competes with the antiferromagnetic Cr-Cr direct interactions. The interlayer antiferromagnetic exchange through Cu atoms leads to magnetic ordering at low temperature at T{sub N}=55 K. - Graphical abstract: Comparison of magnetic properties of CuCrSe{sub 2} and CuCrS{sub 2} indicates a sharp cusp-like anomaly in magnetic susceptibility at the antiferromagnetic transition of CuCrS{sub 2} while the maximum of CuCrSe{sub 2} is well rounded. Magnetization is reversible after field-cooling (FC) and zero-field-cooling (ZFC) for both compounds. Highlights: Black-Right-Pointing-Pointer Layered CuCrSe{sub 2} can be synthesized in both fully and partially cation-ordered forms. Black-Right-Pointing-Pointer Contrary to previously believed insulating nature the cation-ordered phase is metallic. Black-Right-Pointing-Pointer Magnetic property of CuCrSe{sub 2} is somewhat different from that of CuCrS{sub 2}. Black-Right-Pointing-Pointer Magnetization and heat capacity data suggest complex short-range ordering for CuCrSe{sub 2}.

  17. 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.

  18. Steamside Oxidation Behavior of Experimental 9%Cr Steels

    SciTech Connect (OSTI)

    Dogan, O.N.; Holcomb, G.R.; Alman, D.E.; Jablonski, P.D.

    2007-10-01

    Reducing emissions and increasing economic competitiveness require more efficient steam power plants that utilize fossil fuels. One of the major challenges in designing these plants is the availability of materials that can stand the supercritical and ultra-supercritical steam conditions at a competitive cost. There are several programs around the world developing new ferritic and austenitic steels for superheater and reheater tubes exposed to the advanced steam conditions. The new steels must possess properties better than current steels in terms of creep strength, steamside oxidation resistance, fireside corrosion resistance, and thermal fatigue resistance. This paper introduces a series of experimental 9%Cr steels containing Cu, Co, and Ti. Stability of the phases in the new steels is discussed and compared to the phases in the commercially available materials. The steels were tested under both the dry and moist conditions at 650C for their cyclical oxidation resistance. Results of oxidation tests are presented. Under the moist conditions, the experimental steels exhibited significantly less mass gain compared to the commercial P91 steel. Microstructural characterization of the scale revealed different oxide compositions.

  19. Hydrothermal synthesis and magnetic properties of ErCrO{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Sundarayya, Y. Kumar, K. Ashwini Sondge, Rajesh Srinath, S. Kaul, S. N.

    2014-04-24

    Homogeneous single phase ErCrO{sub 4} nanoparticles have been synthesized by a modified sol-gel followed by hydrothermal method. X-ray diffraction reveals that the compound crystallizes into tetragonal structure with space group I41/amd. The average crystallite size was estimated to be 21(1) nm. Morphological analysis of the sample confirms uniform particles of size 20 nm. DC magnetic measurements show that ErCrO{sub 4} undergoes a paramagnetic-antiferromagnetic transition at 16 K, due to the superexchange Er-O-Cr-O-Er antiferromagnetic interactions.

  20. CASL - Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds:

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

    Density functional theory calculations Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds: Density functional theory calculations Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds: Density functional theory calculations D.A. Andersson and C.R. Stanek Materials Science and Technology Division Los Alamos National Laboratory Density functional theory (DFT) calculations have been employed to better understand the thermodynamic properties of AB2O4 (where A=Fe2+, Ni2+ or

  1. Magnetic properties of granular CoCrPt:SiO{sub 2} films as tailored by

    Office of Scientific and Technical Information (OSTI)

    Co{sup +} irradiation (Journal Article) | SciTech Connect Magnetic properties of granular CoCrPt:SiO{sub 2} films as tailored by Co{sup +} irradiation Citation Details In-Document Search Title: Magnetic properties of granular CoCrPt:SiO{sub 2} films as tailored by Co{sup +} irradiation We report on an approach to tailor the magnetic exchange in a conventional granular CoCrPt:SiO{sub 2} recording medium by irradiation with Co{sup +} ions. Irradiation at low fluences enhances the intergranular

  2. Sign reversal of transformation entropy change in Co{sub 2}Cr(Ga,Si) shape

    Office of Scientific and Technical Information (OSTI)

    memory alloys (Journal Article) | SciTech Connect Sign reversal of transformation entropy change in Co{sub 2}Cr(Ga,Si) shape memory alloys Citation Details In-Document Search Title: Sign reversal of transformation entropy change in Co{sub 2}Cr(Ga,Si) shape memory alloys In situ X-ray diffraction (XRD) measurements and compression tests were performed on Co{sub 2}Cr(Ga,Si) shape memory alloys. The reentrant martensitic transformation behavior was directly observed during the in situ XRD

  3. Epitaxial Cr on n-SrTiO3(001)An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, Cigdem; Sun, Guangyuan; Bowden, Mark E.; Chambers, Scott A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO3(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO2 layer, no reduction of the SrTiO3, and a near-perfect Ohmic contact. Cr/n-SrTiO3(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  4. Epitaxial Cr on n-SrTiO{sub 3}(001) - An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, C.; Sun, G. Y.; Bowden, M. E.; Chambers, S. A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO{sub 3}(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO{sub 2} layer, no reduction of the SrTiO{sub 3}, and a near-perfect Ohmic contact. Cr/n-SrTiO{sub 3}(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  5. Study of structure of the TiO{sub 2}MoO{sub 3} bilayer films by Raman spectroscopy

    SciTech Connect (OSTI)

    Santos, Elias de Barros; Sigoli, Fernando Aparecido; Mazali, Italo Odone

    2014-12-15

    Highlights: TiO{sub 2}MoO{sub 3} bilayer thin films were easily prepared by dip-coating technique. Ti and Mo metallo-organic compounds were used as source of its respective oxide. TiO{sub 2} in anatase phase and orthorhombic phase of ?-MoO{sub 3} were identified. The bilayer structure was investigated by Raman spectroscopy. - Abstract: In this work, TiO{sub 2}MoO{sub 3} films were easily prepared by dip-coating technique and metallo-organic decomposition process (MOD). Raman analyses indicate the formation of TiO{sub 2} in anatase phase and orthorhombic phase of ?-MoO{sub 3}. It was observed that the Raman bands intensities attributed to TiO{sub 2} and MoO{sub 3} oxides were dependent on the number of decompositiondeposition cycles (DDC). The different number of DDC generates films with different thicknesses and the Raman signal was sensitive to this variation. Raman analyses provided qualitative information about the bilayer structure of the bi-component TiO{sub 2}MoO{sub 3} films, which was confirmed by scanning electron microscopy. In this direction, the dip-coating technique and MOD process can be an efficient strategy to facile preparation of many samples to be used in applications.

  6. Microstructural Characterization of U-7Mo/Al-Si Alloy Matrix Dispersion Fuel Plates Fabricated at 500°C

    SciTech Connect (OSTI)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Bo Yao; Emmanuel Perez; Yongho Sohn; Curtis R. Clark

    2011-05-01

    The starting microstructure of a dispersion fuel plate will impact the overall performance of the plate during irradiation. To improve the understanding of the as-fabricated microstructures of U–Mo dispersion fuel plates, particularly the interaction layers that can form between the fuel particles and the matrix, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses have been performed on samples from depleted U–7Mo (U–7Mo) dispersion fuel plates with either Al–2 wt.% Si(Al–2Si) or AA4043 alloy matrix. It was observed that in the thick interaction layers, U(Al, Si)3 and U6Mo4Al43 were present, and in the thin interaction layers, (U, Mo) (Al, Si)3, U(Al, Si)4, U3Si3Al2, U3Si5, and possibly USi-type phases were observed. The U3Si3Al2 phase contained some Mo. Based on the results of this investigation, the time that a dispersion fuel plate is exposed to a relatively high temperature during fabrication will impact the nature of the interaction layers around the fuel particles. Uniformly thin, Si-rich layers will develop around the U–7Mo particles for shorter exposure times, and thicker, Si-depleted layers will develop for the longer exposure times.

  7. MoS{sub 2}@ZnO nano-heterojunctions with enhanced photocatalysis and field emission properties

    SciTech Connect (OSTI)

    Tan, Ying-Hua; Yu, Ke Li, Jin-Zhu; Fu, Hao; Zhu, Zi-Qiang

    2014-08-14

    The molybdenum disulfide (MoS{sub 2})@ZnO nano-heterojunctions were successfully fabricated through a facile three-step synthetic process: prefabrication of the ZnO nanoparticles, the synthesis of MoS{sub 2} nanoflowers, and the fabrication of MoS{sub 2}@ZnO heterojunctions, in which ZnO nanoparticles were uniformly self-assembled on the MoS{sub 2} nanoflowers by utilizing polyethyleneimine as a binding agent. The photocatalytic activities of the composite samples were evaluated by monitoring the photodegradation of methylene blue (MB). Compared with pure MoS{sub 2} nanoflowers, the composites show higher adsorption capability in dark and better photocatalytic efficiency due to the increased specific surface area and improved electron-hole pair separation. After irradiation for 100?min, the remaining MB in solution is about 7.3%. Moreover, the MoS{sub 2}@ZnO heterojunctions possess enhanced field emission properties with lower turn-on field of 3.08?V ?m{sup ?1}and lower threshold field of 6.9?V ?m{sup ?1} relative to pure MoS{sub 2} with turn-on field of 3.65?V ?m{sup ?1} and threshold field of 9.03?V ?m{sup ?1}.

  8. The effect of f[subscript O2] on the partitioning and valence of V and Cr

    Office of Scientific and Technical Information (OSTI)

    in garnet/melt pairs and the relation to terrestrial mantle V and Cr content (Journal Article) | SciTech Connect Journal Article: The effect of f[subscript O2] on the partitioning and valence of V and Cr in garnet/melt pairs and the relation to terrestrial mantle V and Cr content Citation Details In-Document Search Title: The effect of f[subscript O2] on the partitioning and valence of V and Cr in garnet/melt pairs and the relation to terrestrial mantle V and Cr content Chromium and vanadium

  9. Theoretical study on strain induced variations in electronic properties of 2H-MoS{sub 2} bilayer sheets

    SciTech Connect (OSTI)

    Dong, Liang; Dongare, Avinash M.; Namburu, Raju R.; O'Regan, Terrance P.; Dubey, Madan

    2014-02-03

    The strain dependence of the electronic properties of bilayer sheets of 2H-MoS{sub 2} is studied using ab initio simulations based on density functional theory. An indirect band gap for bilayer MoS{sub 2} is observed for all variations of strain along the basal plane. Several transitions for the indirect band gap are observed for various strains for the bilayer structure. The variation of the band gap and the carrier effective masses for the holes and the electrons for the bilayer MoS{sub 2} structure under conditions of uniaxial strain, biaxial strain, as well as uniaxial stress is investigated.

  10. Audit Report: CR-B-97-04 | Department of Energy

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

    Audit Report: CR-B-97-04 More Documents & Publications Audit of Selected Hazardous Waste Remedial Actions Program Costs, ER-B-97-04 Audit Report: IG-0443 Inspection Report: IG-0369

  11. Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub

    Office of Scientific and Technical Information (OSTI)

    3}Ti{sub 4}O{sub 12}(CCTO) Ceramics (Journal Article) | SciTech Connect Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub 3}Ti{sub 4}O{sub 12}(CCTO) Ceramics Citation Details In-Document Search Title: Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub 3}Ti{sub 4}O{sub 12}(CCTO) Ceramics Effects of Zn and Cr substitutions on dielectric properties of CaCu{sub 3-x}Zn{sub x}Ti{sub 4-y}Cr{sub y}O{sub 12} ceramics are reported. Dielectric measurements at room

  12. In Situ Long-Term Reductive Bioimmobilization of Cr(VI) in Groundwater...

    Office of Scientific and Technical Information (OSTI)

    injection into Cr(VI)-contaminated groundwater stimulates an average increase in biomass by up to 50 times, from-5105 to 2.5107 cellsmL. The results also show a...

  13. Half-metallic ferromagnetism in Cr-doped semiconducting Ge-chalcogenide: Density functional approach

    SciTech Connect (OSTI)

    Saini, Hardev S.; Singh, Mukhtiyar; Thakur, Jyoti; Kashyap, Manish K.

    2014-04-24

    A supercell approach has been used to calculate the electronic and magnetic properties of Cr-doped Ge chalcogenide, Ge{sub 1−x}Cr{sub x}Te (x = 0.25 and 0.125). The calculations have been performed using full potential Linear Augmented Plane Wave (FPLAPW) method within generalized gradient approximation (GGA) as exchange-correlation (XC) potential. The calculated results show that the doping of Cr induces the 100% spin polarization at Fermi level (EF) and showed the robust half metallic ferromagnetism in this compound. Thus, the compound at both dopant concentrations behave as dilute magnetic semiconductor (DMS) showing metallic property in majority and semiconducting for minority spin channels which is best suited for spintronic applications. The total magnetic moments of this compound are mainly due to Cr-d states present at E{sup F} with negligible contribution from electronic states of other atoms.

  14. Demonstration of a Full-core Reactivity Equivalence for FeCrAl...

    Office of Scientific and Technical Information (OSTI)

    Demonstration of a Full-core Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Citation Details In-Document Search Title: Demonstration of a Full-core ...

  15. Flat panel display using Ti-Cr-Al-O thin film

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2002-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  16. Process for producing Ti-Cr-Al-O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2001-01-01

    Thin films of Ti-Cr-Al-O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti-Cr-Al-O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti-Cr-Al-O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti-Cr-Al-O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  17. Audit Report: CR-B-97-01 | Department of Energy

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

    1 Audit Report: CR-B-97-01 October 22, 1996 Audit of Department of Energy's Warehouse Space The downsizing of Department of Energy (Department) facilities as a result of the end of ...

  18. Audit Report: CR-B-95-05 | Department of Energy

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

    of the Federal Enegy Regulatory Commission's Office of Chief Accountant Audit Report: CR-B-95-05 More Documents & Publications Audit Report: IG-0811 Audit Manual Audit Report:...

  19. Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional...

    Office of Scientific and Technical Information (OSTI)

    In this work we for the first time exfoliate the CrSiTe3, a bulk ferromagnetic semiconductor, to mono- and few-layer 2D crystals onto a SiSiO2 substrate. The Raman spectra show ...

  20. Microstructural Stability of 9-12 Cr Steels at Elevated Temperatures

    SciTech Connect (OSTI)

    Dogan, Omer N.; Hawk, Jeffrey A.

    2005-09-01

    The objective of this report is to explore new substitutional solute solution (Cu, Co) and precipitate (TiC) hardening mechanisms for improved strength of 9-12 Cr martensitic steels.

  1. AMoRE: Collaboration for searches for the neutrinoless double-beta decay of the isotope of {sup 100}Mo with the aid of {sup 40}Ca{sup 100}MoO{sub 4} as a cryogenic scintillation detector

    SciTech Connect (OSTI)

    Khanbekov, N. D., E-mail: xanbekov@gmail.com [Institute of Theoretical and Experimental Physics (Russian Federation)

    2013-09-15

    The AMoRE (Advanced Mo based Rare process Experiment) Collaboration is planning to employ {sup 40}Ca{sup 100}MoO{sub 4} single crystals as a cryogenic Scintillation detector for studying the neutrinoless double-beta decay of the isotope {sup 100}Mo. A simultaneous readout of phonon and scintillation signals is performed in order to suppress the intrinsic background. The planned sensitivity of the experiment that would employ 100 kg of {sup 40}Ca{sup 100}MoO{sub 4} over five years of data accumulation would be T{sub 1/2}{sup 0{nu}} = 3 Multiplication-Sign 10{sup 26} yr, which corresponds to values of the effective Majorana neutrino mass in the range of Left-Pointing-Angle-Bracket m{sub {nu}} Right-Pointing-Angle-Bracket {approx} 0.02-0.06 eV.

  2. Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

    SciTech Connect (OSTI)

    Cutting, R. S.; Coker, V. S.; Telling, N. D.; Kimber, R. L.; Pearce, C. I.; Ellis, B.; Lawson, R; van der Laan, G.; Pattrick, R.A.D.; Vaughan, D.J.; Arenholz, E.; Lloyd, J. R.

    2009-09-09

    To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticle surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral substrate supplied to Fe(III)-reducing bacteria.

  3. Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion

    DOE Patents [OSTI]

    Steeves, Arthur F.; Bibb, Albert E.

    1984-01-01

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprising heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cool the alloy body, and heat the cooled body to a temperature between 1100.degree. to 1500.degree. F. for about 1 to 30 hours.

  4. Audit Report: CR-B-97-03 | Department of Energy

    Energy Savers [EERE]

    3 Audit Report: CR-B-97-03 May 6, 1997 Followup Audit on the Procurement of Support Services for the Energy Information Administration PDF icon Audit Report: CR-B-97-03 More Documents & Publications Aligning Contract Incentives & Contract Mgt Trends - David Leotta, Director, Office of Contract Management, OAPM Update on Procurement Opportunities and Acquisition Process OPAM Policy Acquisition Guides

  5. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    DOE Patents [OSTI]

    Park, Jong-Hee (Clarendon Hills, IL); Natesan, Krishnamurti (Naperville, IL); Rink, David L. (Mokena, IL)

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  6. Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional

    Office of Scientific and Technical Information (OSTI)

    ferromagnetic material (Journal Article) | SciTech Connect Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional ferromagnetic material Citation Details In-Document Search This content will become publicly available on November 27, 2016 Title: Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional ferromagnetic material Finite range ferromagnetism and antiferromagnetism in two-dimensional (2D) systems within an isotropic Heisenberg model at non-zero temperature were

  7. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    DOE Patents [OSTI]

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  8. Radiation tolerance of neutron-irradiated model Fe-Cr-Al alloys

    SciTech Connect (OSTI)

    Field, Kevin G.; Hu, Xunxiang; Littrell, Kenneth C.; Yamamoto, Yukinori; Snead, Lance Lewis

    2015-07-14

    The Fe Cr Al alloy system has the potential to form an important class of enhanced accident-tolerant cladding materials in the nuclear power industry owing to the alloy system's higher oxidation resistance in high-temperature steam environments compared with traditional zirconium-based alloys. However, radiation tolerance of Fe Cr Al alloys has not been fully established. In this study, a series of Fe Cr Al alloys with 10 18 wt % Cr and 2.9 4.9 wt % Al were neutron irradiated at 382 C to 1.8 dpa to investigate the irradiation-induced microstructural and mechanical property evolution as a function of alloy composition. Dislocation loops with Burgers vector of a/2 111 and a 100 were detected and quantified. Results indicate precipitation of Cr-rich is primarily dependent on the bulk chromium composition. Mechanical testing of sub-size-irradiated tensile specimens indicates the hardening response seen after irradiation is dependent on the bulk chromium composition. Furthermore, a structure property relationship was developed; it indicated that the change in yield strength after irradiation is caused by the formation of these radiation-induced defects and is dominated by the large number density of Cr-rich α' precipitates at sufficiently high chromium contents after irradiation.

  9. Microstructure and Mechanical Properties of n-irradiated Fe-Cr Model Alloys

    SciTech Connect (OSTI)

    Matijasevic, Milena; Al Mazouzi, Abderrahim

    2008-07-01

    High chromium ( 9-12 wt %) ferritic/martensitic steels are candidate structural materials for future fusion reactors and other advanced systems such as accelerator driven systems (ADS). Their use for these applications requires a careful assessment of their mechanical stability under high energy neutron irradiation and in aggressive environments. In particular, the Cr concentration has been shown to be a key parameter to be optimized in order to guarantee the best corrosion and swelling resistance, together with the least embrittlement. In this work, the characterization of the neutron irradiated Fe-Cr model alloys with different Cr % with respect to microstructure and mechanical tests will be presented. The behavior of Fe-Cr alloys have been studied using tensile tests at different temperature range ( from -160 deg. C to 300 deg. C). Irradiation-induced microstructure changes have been studied by TEM for two different irradiation doses at 300 deg. C. The density and the size distribution of the defects induced have been determined. The tensile test results indicate that Cr content affects the hardening behavior of Fe-Cr binary alloys. Hardening mechanisms are discussed in terms of Orowan type of approach by correlating TEM data to the measured irradiation hardening. (authors)

  10. Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional ferromagnetic material

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

    Lin, Ming -Wei; Zhung, Houlong L.; Yan, Jiaqiang; Ward, Thomas Zac; Puretzky, Alexander A.; Rouleau, Christopher M.; Gai, Zheng; Liang, Liangbo; Meunier, Vincent; Ganesh, Panchapakesan; et al

    2015-11-27

    Finite range ferromagnetism and antiferromagnetism in two-dimensional (2D) systems within an isotropic Heisenberg model at non-zero temperature were originally proposed to be impossible. However, recent theoretical studies using an Ising model have recently shown that 2D magnetic crystals can exhibit magnetism. Experimental verification of existing 2D magnetic crystals in this system has remained elusive. In this work we for the first time exfoliate the CrSiTe3, a bulk ferromagnetic semiconductor, to mono- and few-layer 2D crystals onto a Si/SiO2 substrate. The Raman spectra show the good stability and high quality of the exfoliated flakes, consistent with the computed phonon spectra ofmore » 2D CrSiTe3, giving a strong evidence for the existence of 2D CrSiTe3 crystals. When the thickness of the CrSiTe3 crystals is reduced to few-layers, we observed a clear change in resistivity at 80~120 K, consistent with the theoretical calculations on the Curie temperature (Tc) of ~80 K for the magnetic ordering of 2D CrSiTe3 crystals. As a result, the ferromagnetic mono- and few-layer 2D CrSiTe3 indicated here should enable numerous applications in nano-spintronics.« less

  11. Radiation tolerance of neutron-irradiated model Fe-Cr-Al alloys

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

    Field, Kevin G.; Hu, Xunxiang; Littrell, Kenneth C.; Yamamoto, Yukinori; Snead, Lance Lewis

    2015-07-14

    The Fe Cr Al alloy system has the potential to form an important class of enhanced accident-tolerant cladding materials in the nuclear power industry owing to the alloy system's higher oxidation resistance in high-temperature steam environments compared with traditional zirconium-based alloys. However, radiation tolerance of Fe Cr Al alloys has not been fully established. In this study, a series of Fe Cr Al alloys with 10 18 wt % Cr and 2.9 4.9 wt % Al were neutron irradiated at 382 C to 1.8 dpa to investigate the irradiation-induced microstructural and mechanical property evolution as a function of alloy composition.more » Dislocation loops with Burgers vector of a/2 111 and a 100 were detected and quantified. Results indicate precipitation of Cr-rich is primarily dependent on the bulk chromium composition. Mechanical testing of sub-size-irradiated tensile specimens indicates the hardening response seen after irradiation is dependent on the bulk chromium composition. Furthermore, a structure property relationship was developed; it indicated that the change in yield strength after irradiation is caused by the formation of these radiation-induced defects and is dominated by the large number density of Cr-rich α' precipitates at sufficiently high chromium contents after irradiation.« less

  12. Networks of ultrasmall Pd/Cr bilayer nanowires as high performance hydrogen sensors.

    SciTech Connect (OSTI)

    Zeng, X.-Q.; Wang, Y.-L.; Deng, H.; Latimer, M. L.; Xiao, Z.-L.; Pearson, J.; Xu, T.; Wang, H.-H.; Welp, U.; Crabtree, G. W.; Kwok, W.-K.

    2011-01-01

    The newly developed hydrogen sensor, based on a network of ultrasmall pure palladium nanowires sputter-deposited on a filtration membrane, takes advantage of single palladium nanowires' characteristics of high speed and sensitivity while eliminating their nanofabrication obstacles. However, this new type of sensor, like the single palladium nanowires, cannot distinguish hydrogen concentrations above 3%, thus limiting the potential applications of the sensor. This study reports hydrogen sensors based on a network of ultrasmall Cr-buffered Pd (Pd/Cr) nanowires on a filtration membrane. These sensors not only are able to outperform their pure Pd counterparts in speed and durability but also allow hydrogen detection at concentrations up to 100%. The new networks consist of a thin layer of palladium deposited on top of a Cr adhesion layer 1-3 nm thick. Although the Cr layer is insensitive to hydrogen, it enables the formation of a network of continuous Pd/Cr nanowires with thicknesses of the Pd layer as thin as 2 nm. The improved performance of the Pd/Cr sensors can be attributed to the increased surface area to volume ratio and to the confinement-induced suppression of the phase transition from Pd/H solid solution ({alpha}-phase) to Pd hydride ({beta}-phase).

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

    SciTech Connect (OSTI)

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

    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. 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, |M|, 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.

  14. Microstructure evolution in solution treated Ti15Mo alloy processed by high pressure torsion

    SciTech Connect (OSTI)

    Jane?ek, Milo; ?ek, Jakub; Strsk, Josef; Vclavov, Kristna; Hruka, Petr; Polyakova, Veronika; Gatina, Svetlana; Semenova, Irina

    2014-12-15

    Microstructure evolution and mechanical properties of ultra-fine grained Ti15Mo alloy processed by high pressure torsion were investigated. High pressure torsion straining resulted in strong grain refinement as-observed by transmission electron microscopy. Microhardness and light microscopy showed two distinct regions (i) a central region with radial material flow and low microhardness (340 HV) and (ii) a peripheral region with rotational material flow and high microhardness (430 HV). Positron annihilation spectroscopy showed that the only detectable defects in the material are dislocations, whose density increases with the radial distance and the number of high pressure torsion revolutions. The local chemical environment around defects does not differ significantly from the average composition. - Highlights: Beta-Ti alloy Ti15Mo was processed by high pressure torsion (HPT). Lateral inhomogeneity of the microstructure and microhardness was found. Dislocations are the only lattice defects detectable by positron annihilation. Molybdenum is not preferentially segregated along dislocation cores.

  15. 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.

  16. A multiscale method for the analysis of defect behavior in MO during electron irradiation

    SciTech Connect (OSTI)

    Rest, J.; Insepov, Z.; Ye, B.; Yun, D.

    2014-10-01

    In order to overcome a lack of experimental information on values for key materials properties and kinetic coefficients, a multiscale modeling approach is applied to defect behavior in irradiated Mo where key materials properties, such as point defect (vacancy and interstitial) migration enthalpies as well as kinetic factors such as dimer formation, defect recombination, and self interstitial–interstitial loop interaction coefficients, are obtained by molecular dynamics calculations and implemented into rate-theory simulations of defect behavior. The multiscale methodology is validated against interstitial loop growth data obtained from electron irradiation of pure Mo. It is shown that the observed linear behavior of the loop diameter vs. the square root of irradiation time is a direct consequence of the 1D migration of self-interstitial atoms.

  17. Chemical isolation of .sup.82 Sr from proton-irradiated Mo targets

    DOE Patents [OSTI]

    Grant, Patrick M.; Kahn, Milton; O'Brien, Jr., Harold A.

    1976-01-01

    Spallation reactions are induced in Mo targets with 200-800 MeV protons to produce microcurie to millicurie amounts of a variety of radionuclides. A six-step radiochemical procedure, incorporating precipitation, solvent extractions, and ion exchange techniques, has been developed for the separation and purification of Sr radioactivities from other spallation products and the bulk target material. Radiostrontium can be quantitatively recovered in a sufficiently decontaminated state for use in biomedical generator development.

  18. Production and Characterization of Atomized U-Mo Powder by the Rotating Electrode Process

    SciTech Connect (OSTI)

    C.R. Clark; B.R. Muntifering; J.F. Jue

    2007-09-01

    In order to produce feedstock fuel powder for irradiation testing, the Idaho National Laboratory has produced a rotating electrode type atomizer to fabricate uranium-molybdenum alloy fuel. Operating with the appropriate parameters, this laboratory-scale atomizer produces fuel in the desired size range for the RERTR dispersion experiments. Analysis of the powder shows a homogenous, rapidly solidified microstructure with fine equiaxed grains. This powder has been used to produce irradiation experiments to further test adjusted matrix U-Mo dispersion fuel.

  19. Co-Rolled U10Mo/Zirconium-Barrier-Layer Monolithic Fuel Foil Fabrication Process

    SciTech Connect (OSTI)

    G. A. Moore; M. C. Marshall

    2010-01-01

    Integral to the current UMo fuel foil processing scheme being developed at Idaho National Laboratory (INL) is the incorporation of a zirconium barrier layer for the purpose of controlling UMo-Al interdiffusion at the fuel-meat/cladding interface. A hot “co-rolling” process is employed to establish a ~25-µm-thick zirconium barrier layer on each face of the ~0.3-mm-thick U10Mo fuel foil.

  20. 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.

  1. Crystal structure of the spin-glass pyrochlore, Y/sub 2/Mo/sub 2/O/sub 7/

    SciTech Connect (OSTI)

    Reimers, J.N.; Greedan, J.E.; Sato, M.

    1988-02-01

    The crystal structure of the spin-glass material, Y/sub 2/Mo/sub 2/O/sub 7/, has been determined from powder neutron diffraction data using profile (Rietveld) methods. The data are consistent with the fully ordered cubic pyrochlore structure, a/sub 0/ = 10.230(1) A with Y in 16d, Mo in 16c, O in 48f(x = 0.3382(1), and O' in 8b of Fd3m. Attempts to refine models with O' disordered over the 32e sites or between the 8a and 8b sites resulted in convergence to the 8b positions. Derived Y-O and Mo-O distances are in excellent agreement with those found in isostructural materials giving indirect evidence for Y-Mo ordering over the cation sites.

  2. Exciton-dominated dielectric function of atomically thin MoS2 films

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

    Yu, Yiling; Yu, Yifei; Cai, Yongqing; Li, Wei; Gurarslan, Alper; Peelaers, Hartwin; Aspnes, David E.; Van de Walle, Chris G.; Nguyen, Nhan V.; Zhang, Yong -Wei; et al

    2015-11-24

    We systematically measure the dielectric function of atomically thin MoS2 films with different layer numbers and demonstrate that excitonic effects play a dominant role in the dielectric function when the films are less than 5–7 layers thick. The dielectric function shows an anomalous dependence on the layer number. It decreases with the layer number increasing when the films are less than 5–7 layers thick but turns to increase with the layer number for thicker films. We show that this is because the excitonic effect is very strong in the thin MoS2 films and its contribution to the dielectric function maymore » dominate over the contribution of the band structure. We also extract the value of layer-dependent exciton binding energy and Bohr radius in the films by fitting the experimental results with an intuitive model. The dominance of excitonic effects is in stark contrast with what reported at conventional materials whose dielectric functions are usually dictated by band structures. Lastly, the knowledge of the dielectric function may enable capabilities to engineer the light-matter interactions of atomically thin MoS2 films for the development of novel photonic devices, such as metamaterials, waveguides, light absorbers, and light emitters.« less

  3. Study on Shielding Requirements for Radioactive Waste Transportation in a Mo-99 Production Plant - 13382

    SciTech Connect (OSTI)

    Melo Rego, Maria Eugenia de; Kazumi Sakata, Solange; Vicente, Roberto; Hiromoto, Goro [Nuclear and Energy Research Institute, IPEN-CNEN/SP (Brazil)] [Nuclear and Energy Research Institute, IPEN-CNEN/SP (Brazil)

    2013-07-01

    Brazil is currently planning to produce {sup 99}Mo from fission of low enriched uranium (LEU) targets. The planned end of irradiation activity of {sup 99}Mo is about 185 TBq (5 kCi) per week to meet the present domestic demand of {sup 99m}Tc generators. The radioactive wastes from the production plant will be transferred to a waste treatment facility at the same site. The total activity of the actinides, fission and activation products present in the wastes can be predicted based on the yields of fission and activation data for the irradiation conditions, such as composition and mass of uranium targets, irradiation time, neutron flux, production schedule, etc., which were in principle already established by the project management. The transportation of the wastes from the production plant to the treatment facility will be done by means of special shielded packages. An assessment of the shielding required for the packages has been done and the results are presented here, aiming at contributing to the design of the waste management facility for the {sup 99}Mo production plant. (authors)

  4. Exciton-dominated dielectric function of atomically thin MoS2 films

    SciTech Connect (OSTI)

    Yu, Yiling; Yu, Yifei; Cai, Yongqing; Li, Wei; Gurarslan, Alper; Peelaers, Hartwin; Aspnes, David E.; Van de Walle, Chris G.; Nguyen, Nhan V.; Zhang, Yong -Wei; Cao, Linyou

    2015-11-24

    We systematically measure the dielectric function of atomically thin MoS2 films with different layer numbers and demonstrate that excitonic effects play a dominant role in the dielectric function when the films are less than 5–7 layers thick. The dielectric function shows an anomalous dependence on the layer number. It decreases with the layer number increasing when the films are less than 5–7 layers thick but turns to increase with the layer number for thicker films. We show that this is because the excitonic effect is very strong in the thin MoS2 films and its contribution to the dielectric function may dominate over the contribution of the band structure. We also extract the value of layer-dependent exciton binding energy and Bohr radius in the films by fitting the experimental results with an intuitive model. The dominance of excitonic effects is in stark contrast with what reported at conventional materials whose dielectric functions are usually dictated by band structures. Lastly, the knowledge of the dielectric function may enable capabilities to engineer the light-matter interactions of atomically thin MoS2 films for the development of novel photonic devices, such as metamaterials, waveguides, light absorbers, and light emitters.

  5. Tribological properties of self-lubricating NiAl/Mo-based composites containing AgVO{sub 3} nanowires

    SciTech Connect (OSTI)

    Liu, Eryong; Gao, Yimin; Bai, Yaping; Yi, Gewen; Wang, Wenzhen; Zeng, Zhixiang; Jia, Junhong

    2014-11-15

    Silver vanadate (AgVO{sub 3}) nanowires were synthesized by hydrothermal method and self-lubricating NiAl/Mo-AgVO{sub 3} composites were fabricated by powder metallurgy technique. The composition and microstructure of NiAl/Mo-based composites were characterized and the tribological properties were investigated from room temperature to 900 C. The results showed that NiAl/Mo-based composites were consisted of nanocrystalline B2 ordered NiAl matrix, Al{sub 2}O{sub 3}, Mo{sub 2}C, metallic Ag and vanadium oxide phase. The appearance of metallic Ag and vanadium oxide phase can be attributed to the decomposition of AgVO{sub 3} during sintering. Wear testing results confirmed that NiAl/Mo-based composites have excellent tribological properties over a wide temperature range. For example, the friction coefficient and wear rate of NiAl/Mo-based composites containing AgVO{sub 3} were significantly lower than the composites containing only metallic Mo or AgVO{sub 3} lubricant when the temperature is above 300 C, which can be attributed to the synergistic lubricating action of metallic Mo and AgVO{sub 3} lubricants. Furthermore, Raman results indicated that the composition on the worn surface of NiAl-based composites was self-adjusted after wear testing at different temperatures. For example, Ag{sub 3}VO{sub 4} and Fe{sub 3}O{sub 4} lubricants were responsible for the improvement of tribological properties at 500 C, AgVO{sub 3}, Ag{sub 3}VO{sub 4} and molybdate for 700 C, and AgVO{sub 3} and molybdate for 900 C of NiAl-based composites with the addition of metallic Mo and AgVO{sub 3}. - Highlights: NiAl/Mo-AgVO{sub 3} nanocomposites were prepared by mechanical alloying and sintering. AgVO{sub 3} decomposed to metallic Ag and vanadium oxide during the sintering process. NiAl/Mo-AgVO{sub 3} exhibited superior tribological properties at a board temperature range. Phase composition on the worn surface was varied with temperatures. Self-adjusted action was responsible for the improvement of tribological properties.

  6. Electronic structure, magnetism, and antisite disorder in CoFeCrGe and CoMnCrAl quaternary Heusler alloys

    SciTech Connect (OSTI)

    Enamullah, .; Venkateswara, Y.; Gupta, Sachin; Varma, Manoj Raama; Singh, Prashant; Suresh, K. G.; Alam, Aftab

    2015-12-10

    In this study, we present a combined theoretical and experimental study of two quaternary Heusler alloys CoFeCrGe (CFCG) and CoMnCrAl (CMCA), promising candidates for spintronics applications. Magnetization measurement shows the saturation magnetization and transition temperature to be 3 μB, 866 K and 0.9 μB, 358 K for CFCG and CMCA respectively. The magnetization values agree fairly well with our theoretical results and also obey the Slater-Pauling rule, a prerequisite for half metallicity. A striking difference between the two systems is their structure; CFCG crystallizes in fully ordered Y-type structure while CMCA has L21 disordered structure. The antisite disorder adds a somewhat unique property to the second compound, which arises due to the probabilistic mutual exchange of Al positions with Cr/Mn and such an effect is possibly expected due to comparable electronegativities of Al and Cr/Mn. Ab initio simulation predicted a unique transition from half metallic ferromagnet to metallic antiferromagnet beyond a critical excess concentration of Al in the alloy.

  7. Electronic structure, magnetism, and antisite disorder in CoFeCrGe and CoMnCrAl quaternary Heusler alloys

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

    Enamullah, .; Venkateswara, Y.; Gupta, Sachin; Varma, Manoj Raama; Singh, Prashant; Suresh, K. G.; Alam, Aftab

    2015-12-10

    In this study, we present a combined theoretical and experimental study of two quaternary Heusler alloys CoFeCrGe (CFCG) and CoMnCrAl (CMCA), promising candidates for spintronics applications. Magnetization measurement shows the saturation magnetization and transition temperature to be 3 μB, 866 K and 0.9 μB, 358 K for CFCG and CMCA respectively. The magnetization values agree fairly well with our theoretical results and also obey the Slater-Pauling rule, a prerequisite for half metallicity. A striking difference between the two systems is their structure; CFCG crystallizes in fully ordered Y-type structure while CMCA has L21 disordered structure. The antisite disorder adds amore » somewhat unique property to the second compound, which arises due to the probabilistic mutual exchange of Al positions with Cr/Mn and such an effect is possibly expected due to comparable electronegativities of Al and Cr/Mn. Ab initio simulation predicted a unique transition from half metallic ferromagnet to metallic antiferromagnet beyond a critical excess concentration of Al in the alloy.« less

  8. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy

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

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A.; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T.; Chi, Miaofang; et al

    2016-04-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically-thin electronics and optoelectronics due to their diverse functionalities. While heterostructures consisting of different transition metal dichacolgenide monolayers with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) or edge epitaxy, constructing heterostructures from monolayers of layered semiconductors with large lattice misfits still remains challenging. Here, we report the growth of monolayer GaSe/MoSe2 heterostructures with large lattice misfit by two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between themore » two layers, forming an incommensurate vdW heterostructure. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructure at the crystal interface. Such vertically-stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photo-generated charge carriers between layers, resulting in a gate-tunable photovoltaic response. In conclusion, these GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells.« less

  9. Physicochemical properties of Dy/sup 3 +/ in single KY(MoO/sub 4/)/sub 2/

    Office of Scientific and Technical Information (OSTI)

    crystal (electron absorption, emission, IR, Raman, and magnetic data) (Journal Article) | SciTech Connect Physicochemical properties of Dy/sup 3 +/ in single KY(MoO/sub 4/)/sub 2/ crystal (electron absorption, emission, IR, Raman, and magnetic data) Citation Details In-Document Search Title: Physicochemical properties of Dy/sup 3 +/ in single KY(MoO/sub 4/)/sub 2/ crystal (electron absorption, emission, IR, Raman, and magnetic data) Electron absorption, luminescence, vibrational, and

  10. Electrical properties of a-C:Mo films produced by dual-cathode filtered cathodic arc plasma deposition

    SciTech Connect (OSTI)

    Sansongsiri, Sakon; Anders, Andre; Yodsombat, Banchob

    2008-01-20

    Molybdenum-containing amorphous carbon (a-C:Mo) thin films were prepared using a dual-cathode filtered cathodic arc plasma source with a molybdenum and a carbon (graphite) cathode. The Mo content in the films was controlled by varying the deposition pulse ratio of Mo and C. Film sheet resistance was measured in situ at process temperature, which was close to room temperature, as well as ex situ as a function of temperature (300-515 K) in ambient air. Film resistivity and electrical activation energy were derived for different Mo and C ratios and substrate bias. Film thickness was in the range 8-28 nm. Film resistivity varied from 3.55x10-4 Omega m to 2.27x10-6 Omega m when the Mo/C pulse ratio was increased from 0.05 to 0.4, with no substrate bias applied. With carbon-selective bias, the film resistivity was in the range of 4.59x10-2 and 4.05 Omega m at a Mo/C pulse ratio of 0.05. The electrical activation energy decreased from 3.80x10-2 to 3.36x10-4 eV when the Mo/C pulse ratio was increased in the absence of bias, and from 0.19 to 0.14 eV for carbon-selective bias conditions. The resistivity of the film shifts systematically with the amounts of Mo and upon application of substrate bias voltage. The intensity ratio of the Raman D-peak and G-peak (ID/IG) correlated with the pre-exponential factor (sigma 0) which included charge carrier density and density of states.

  11. Superconducting and structural properties of {delta}-MoC{sub 0.681} cubic molybdenum carbide phase

    SciTech Connect (OSTI)

    Sathish, C.I. [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan) [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Guo, Yanfeng, E-mail: GUO.Yanfeng@nims.go.jp [Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Wang, Xia [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan) [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Tsujimoto, Yoshihiro [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Li, Jun [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan) [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Zhang, Shoubao [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Matsushita, Yoshitaka [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan)] [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Shi, Youguo; Tian, Huanfang; Yang, Huaixin; Li, Jianqi [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)] [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yamaura, Kazunari, E-mail: YAMAURA.Kazunari@nims.go.jp [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan) [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2012-12-15

    The superconducting and lattice properties of {delta}-MoC{sub 0.681} were studied by electromagnetic measurements, synchrotron X-ray diffraction, neutron diffraction, and electron diffraction. The superconducting properties (T{sub c}=12 K) of {delta}-MoC{sub 0.681} were well characterized by a weak coupling model. The carbon vacancies present in the host cubic structure were found to be robust, although the material was synthesized from stoichiometric carbon and Mo powder under a high-pressure of 6 GPa. A thermodynamically-stable structure with ordered vacancies did not account for the robust features of {delta}-MoC{sub 0.681} since the vacancies are unlikely to be ordered in long range in the host structure. A model based on inherent phonon instability theoretically predicted for a stoichiometric MoC phase might be responsible for the robust features of {delta}-MoC{sub 0.681}. - Graphical Abstract: The cubic molybdenum carbide shows an excellent superconductivity with robust carbon vacancies. Inherent phonon instability theoretically predicted for a stoichiometric MoC phase might be responsible for the vacancies rather than a thermodynamically-stable structure with vacancies ordering. Highlights: Black-Right-Pointing-Pointer The 12 K superconductivity is well characterized by a weakly coupling model. Black-Right-Pointing-Pointer Carbon vacancies are robust and disordered in the cubic host structure. Black-Right-Pointing-Pointer Inherent phonon instability might be responsible for the robust carbon vacancies in {delta}-MoC{sub 0.681}.

  12. Preparation of Al{sub 2}O{sub 3}/Mo nanocomposite powder via chemical route and spray drying

    SciTech Connect (OSTI)

    Lo, M.; Cheng, F.; Wei, W.J.

    1996-08-01

    A route to prepare nanometer-sized Mo particulates in Al{sub 2}O{sub 3} was attempted by a combination of solution reactions in molecular scale and forcing precipitation by a spray-drying technique. MoO{sub 3} was first dissolved in ammonia water and then added in the slurry with high purity, submicrometer Al{sub 2}O{sub 3} powder. Mixed suspension was spray-dried, and then the dried granules were reduced by hydrogen gas and further hot-pressing to a bulky composite at various temperatures. Dissolution of Mo oxide, adsorption reactions on alumina surface, and surface potential of alumina particles in homogeneous ammonia suspension were studied. Characterization of the granules, including compactability, flowing properties, surface morphology, grain growth of Mo and Al{sub 2}O{sub 3}, and mixing homogeneity, were examined. Homogeneity of the spray-dried granules was determined by the calculation of mixing index and the observation of the microstructure of sintered body. The existence of intergranular, intragranular, and nanosized Mo particulates within Al{sub 2}O{sub 3} grains was observed by transmission electron microscopy (TEM). All the evidences revealed that homogeneous composites with nanometer-sized Mo had been successfully prepared by this attempt with the proposed chemical route and following spray-drying process. {copyright}{ital 1996 Materials Research Society.}

  13. Low-frequency 1/f noise in MoS{sub 2} transistors: Relative contributions of the channel and contacts

    SciTech Connect (OSTI)

    Renteria, J.; Jiang, C.; Samnakay, R.; Rumyantsev, S. L.; Goli, P.; Balandin, A. A.; Shur, M. S.

    2014-04-14

    We report on the results of the low-frequency (1/f, where f is frequency) noise measurements in MoS{sub 2} field-effect transistors revealing the relative contributions of the MoS{sub 2} channel and Ti/Au contacts to the overall noise level. The investigation of the 1/f noise was performed for both as fabricated and aged transistors. It was established that the McWhorter model of the carrier number fluctuations describes well the 1/f noise in MoS{sub 2} transistors, in contrast to what is observed in graphene devices. The trap densities extracted from the 1/f noise data for MoS{sub 2} transistors, are 2??10{sup 19}?eV{sup ?1}cm{sup ?3} and 2.5??10{sup 20}?eV{sup ?1}cm{sup ?3} for the as fabricated and aged devices, respectively. It was found that the increase in the noise level of the aged MoS{sub 2} transistors is due to the channel rather than the contact degradation. The obtained results are important for the proposed electronic applications of MoS{sub 2} and other van der Waals materials.

  14. Kinetic study of hydrogen evolution reaction on Ni{sub 30} Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70} and Co{sub 10}Ni{sub 20}Mo{sub 70} alloy electrodes

    SciTech Connect (OSTI)

    Dominguez-Crespo, M.A.; Plata-Torres, M.; Torres-Huerta, A.M.; Arce-Estrada, E.M. . E-mail: earce@ipn.mx; Hallen-Lopez, J.M.

    2005-07-15

    The hydrogen evolution reaction on nanocrystalline Ni{sub 30}Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70}, and Co{sub 10}Ni{sub 20}Mo{sub 70}, metallic powders prepared by mechanical alloying was investigated with linear polarization and ac impedance methods, in 30 wt.% KOH aqueous solution at room temperature. The formation process and structural properties of these nanocrystalline materials were characterized by X-ray diffraction and transmission electron microscopy. Alloyed powders showed the presence of two phases: an fcc solid solution and intermetallic compounds of Ni, Co and Mo. Based on polarization and ac impedance measurements, an improved electrocatalytic activity for hydrogen evolution reaction was observed in mechanically alloyed Co{sub 30}Ni{sub 70} powders, which is slightly higher than milled metallic Ni powders.

  15. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600?C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600?C. TiN film deposited at 600?C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600?C on Si(111) wafer but the film deposited at 500?C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600?C. Nitride film of tungsten deposited at 600?C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500?C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600?C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

  16. Characterization of few-layer 1T-MoSe{sub 2} and its superior performance in the visible-light induced hydrogen evolution reaction

    SciTech Connect (OSTI)

    Gupta, Uttam; Naidu, B. S.; Maitra, Urmimala; Rao, C. N. R.; Singh, Anjali; Shirodkar, Sharmila N.; Waghmare, Umesh V.

    2014-09-01

    Based on earlier results on the photocatalytic properties of MoS{sub 2}, the 1T form of MoSe{sub 2}, prepared by lithium intercalation and exfoliation of bulk MoSe{sub 2}, has been employed for the visible-light induced generation of hydrogen. 1T-MoSe{sub 2} is found to be superior to both 2H and 1T MoS{sub 2} as well as 2H-MoSe{sub 2} in producing hydrogen from water, the yield being in the 6075 mmol?h{sup ?1}?g{sup ?1} range with a turn over frequency of 1519 h{sup ?1}. First principles calculations reveal that 1T-MoSe{sub 2} has a lower work function than 2H-MoSe{sub 2} as well as 1T and 2H-MoS{sub 2}, making it easier to transfer an electron from 1T-MoSe{sub 2} for the production of H{sub 2}.

  17. A practical grinding-assisted dry synthesis of nanocrystalline NiMoO{sub 4} polymorphs for oxidative dehydrogenation of propane

    SciTech Connect (OSTI)

    Chen Miao; Wu Jialing; Liu Yongmei; Cao Yong; Guo Li; He Heyong; Fan Kangnian

    2011-12-15

    A practical two-stage reactive grinding-assisted pathway waste-free and cost-effective for the synthesis of NiMoO{sub 4} has been successfully developed. It was demonstrated that proper design in synthetic strategy for grinding plays a crucial role in determining the ultimate polymorph of NiMoO{sub 4}. Specifically, direct grinding (DG) of MoO{sub 3} and NiO rendered {alpha}-NiMoO{sub 4} after annealing, whereas sequential grinding (SG) of the two independently pre-ground oxides followed by annealing generated {beta}-NiMoO{sub 4} solid solution. Characterizations in terms of Raman and X-ray diffraction suggest the creation of {beta}-NiMoO{sub 4} precursor in the latter alternative is the key aspect for the formation of {beta}-NiMoO{sub 4}. The DG-derived {alpha}-NiMoO{sub 4} tested by oxidative dehydrogenation of propane exhibited superior activity in contrast to its analog synthesized via conventional coprecipitation. It is suggested that the favorable chemical composition facilely obtained via grinding in contrast to that by coprecipitation was essential for achieving a more selective production of propylene. - Graphical Abstract: Grinding-assisted synthesis of NiMoO{sub 4} offers higher and more reproducible activities in contrast to coprecipitation for oxidative dehydrogenation of propane, and both {alpha}- and {beta}-NiMoO{sub 4} can be synthesized. Highlights: Black-Right-Pointing-Pointer NiMoO{sub 4} was prepared through grinding-assisted pathway. Black-Right-Pointing-Pointer Direct/sequential grinding rendered {alpha}-, {beta}-NiMoO{sub 4}, respectively. Black-Right-Pointing-Pointer Grinding-derived {alpha}-NiMoO{sub 4} showed high and reproducible activity for oxidative dehydrogenation of propane.

  18. Influence of the hydration by the environmental humidity on the metallic speciation and the photocatalytic activity of Cr/MCM-41

    SciTech Connect (OSTI)

    Elías, Verónica R.; Sabre, Ema V.; Winkler, Elin L.; Andrini, Leandro; Requejo, Félix G.; Casuscelli, Sandra G.; Eimer, Griselda A.

    2014-05-01

    The influence of the environmental humidity on the Cr species deposited on inorganic supports like MCM-41 silicates was analyzed by UV–vis Diffuse Reflectance (UV–vis RD), Electronic Spin Resonance (ESR) and X-ray near-edge (XANES) spectroscopy. Metal speciation could be inferred, finding that prolonged exposure periods under environmental humidity provoked the reduction of the active Cr{sup 6+} species and thus, the decrease of the Cr/MCM-41 photoactivity. After the Ti loading over the Cr modified samples, Cr species and the photoactivity were not notably influenced by the humidity exposure. Thus, it could be concluded that the presence of Ti is important because the TiO{sub 2} cover protects the oxidized Cr species, stabilizing them. - Graphical abstract: The load of Ti on the Cr modified MCM-41 produces a TiO{sub 2} cover that protects the active Cr species from their reduction by the environmental humidity. - Highlights: • Spectroscopic analysis shows presence of Cr{sup 6+}/Cr{sup 5+} in calcined/re-calcined samples. • Cr{sup 3+} species increase for hydrated samples causing their photoactivity decrease. • Samples with high Cr loadings are more sensitive to environmental humidity presence. • TiO{sub 2} cover protects oxidized Cr species from their reduction by the water. • Ti is important to allow a synergistic effect and to stabilize active Cr{sup 6+}/Cr{sup 5+}.

  19. Ablation and cone formation mechanism on CR-39 by ArF laser irradiation

    SciTech Connect (OSTI)

    Shakeri Jooybari, B. E-mail: hafarideh@aut.ac.ir; Afarideh, H. E-mail: hafarideh@aut.ac.ir; Lamehi-Rachti, M.; Ghergherehchi, M.

    2015-03-07

    In this work, chemical properties, surface modification, and micro structures formation on ablated polyallyl di-glycol carbonate (CR-39) polymer by ArF laser irradiation (λ = 193 nm) at various fluences and pulse number were investigated. CR-39 samples have been irradiated with an ArF laser (193 nm) at a repetition rate of 1 Hz. Threshold fluence of ablation and effective absorption coefficient of CR-39 were determined. Conical microstructures (Taylor cone) formed on laser-ablated CR-39 exhibit: smooth, Taylor cone shape walls and sharp tips together with interference and well defined fringe-structure with a period of 230 nm, around cone base. Mechanism of cone formation and cone evolution of CR-39 ablated surface were investigated by change of fluences (at a given pulse number) and pulse number (at a given fluence). Cone height, cone base, and region of interface were increased in micrometer steps by increasing the total fluence. Depression on the base of the cone and the circular fringe were simulated. FTIR spectra were measured and energy dispersive x-ray analysis of irradiated and un-irradiated samples was performed.

  20. Irradiation-induced formation of a spinel phase at the FeCr/MgO interface

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

    Xu, Yun; Yadav, Satyesh Kumar; Aguiar, Jeffery A.; Anderoglu, Osman; Baldwin, Jon Kevin; Wang, Yongqiang; Misra, Amit; Luo, Hongmei; Uberuaga, Blas P.; Li, Nan

    2015-04-27

    Oxide dispersion strengthened ferritic/martensitic alloys have attracted significant attention for their potential uses in future nuclear reactors and storage vessels, as the metal/oxide interfaces act as stable high-strength sinks for point defects while also dispersing helium. Here, in order to unravel the evolution and interplay of interface structure and chemistry upon irradiation in these types of materials, an atomically sharp FeCr/MgO interface was synthesized at 500 °C and separately annealed and irradiated with Ni3+ ions at 500 °C. After annealing, a slight enrichment of Cr atoms was observed at the interface, but no other structural changes were found. However, undermore » irradiation, sufficient Cr diffuses across the interface into the MgO to form a Cr-enriched transition layer that contains spinel precipitates. First-principles calculations indicate that it is energetically favorable to incorporate Cr, but not Fe, substitutionally into MgO. Furthermore, our results indicate that irradiation can be used to form new phases and complexions at interfaces, which may have different radiation tolerance than the pristine structures.« less

  1. Irradiation-induced formation of a spinel phase at the FeCr/MgO interface

    SciTech Connect (OSTI)

    Xu, Yun; Yadav, Satyesh Kumar; Aguiar, Jeffery A.; Anderoglu, Osman; Baldwin, Jon Kevin; Wang, Yongqiang; Misra, Amit; Luo, Hongmei; Uberuaga, Blas P.; Li, Nan

    2015-04-27

    Oxide dispersion strengthened ferritic/martensitic alloys have attracted significant attention for their potential uses in future nuclear reactors and storage vessels, as the metal/oxide interfaces act as stable high-strength sinks for point defects while also dispersing helium. Here, in order to unravel the evolution and interplay of interface structure and chemistry upon irradiation in these types of materials, an atomically sharp FeCr/MgO interface was synthesized at 500 °C and separately annealed and irradiated with Ni3+ ions at 500 °C. After annealing, a slight enrichment of Cr atoms was observed at the interface, but no other structural changes were found. However, under irradiation, sufficient Cr diffuses across the interface into the MgO to form a Cr-enriched transition layer that contains spinel precipitates. First-principles calculations indicate that it is energetically favorable to incorporate Cr, but not Fe, substitutionally into MgO. Furthermore, our results indicate that irradiation can be used to form new phases and complexions at interfaces, which may have different radiation tolerance than the pristine structures.

  2. Production of Ni-Cr-Ti-natural fibres composite and investigation of mechanical properties

    SciTech Connect (OSTI)

    Pesmen, G.; Erol, A.

    2015-03-30

    Intermetallic materials such as Ni{sub 2}Ti, Cr{sub 2}Ti are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially creep resistance, low density and high hardness properties stand out in such intermetallics. The microstructure, mechanical properties of (%50Ni-%48Cr-%2Ti)-%10Naturel Fibres and (%64Ni-%32Cr-%4Ti)-%10Naturel Fibres powders were investigated using specimens produced by tube furnace sintering at 1000-1200-1400C temperature. A composite consisting of ternary additions, a metallic phase, Ti,Cr and Ni have been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), were investigated to characterize the properties of the specimens. Experimental results carried out for composition (%64Ni-%32Cr-%4Ti)-%10Naturel at 1400C suggest that the best properties as 112.09HV and 5,422g/cm{sup 3} density were obtained at 1400C.

  3. Enhanced piezoelectric output voltage and Ohmic behavior in Cr-doped ZnO nanorods

    SciTech Connect (OSTI)

    Sinha, Nidhi; Ray, Geeta; Godara, Sanjay; Gupta, Manoj K.; Kumar, Binay

    2014-11-15

    Highlights: • Low cost highly crystalline Cr-doped ZnO nanorods were synthesized. • Enhancement in dielectric, piezoelectric and ferroelectric properties were observed. • A high output voltage was obtained in AFM. • Cr-doping resulted in enhanced conductivity and better Ohmic behavior in ZnO/Ag contact. - Abstract: Highly crystalline Cr-doped ZnO nanorods (NRs) were synthesized by solution technique. The size distribution was analyzed by high resolution tunneling electron microscope (HRTEM) and particle size analyzer. In atomic force microscope (AFM) studies, peak to peak 8 mV output voltage was obtained on the application of constant normal force of 25 nN. It showed high dielectric constant (980) with phase transition at 69 °C. Polarization vs. electric field (P–E) loops with remnant polarization (6.18 μC/cm{sup 2}) and coercive field (0.96 kV/cm) were obtained. In I–V studies, Cr-doping was found to reduce the rectifying behavior in the Ag/ZnO Schottky contact which is useful for field effect transistor (FET) and solar cell applications. With these excellent properties, Cr-doped ZnO NRs can be used in nanopiezoelectronics, charge storage and ferroelectric applications.

  4. Atom probe study of irradiation-enhanced α' precipitation in neutron-irradiated Fe–Cr model alloys

    SciTech Connect (OSTI)

    Chen, Wei -Ying; Miao, Yinbin; Wu, Yaqiao; Tomchik, Carolyn A.; Mo, Kun; Gan, Jian; Okuniewski, Maria A.; Maloy, Stuart A.; Stubbins, James F.

    2015-07-01

    Atom probe tomography (APT) was performed to study the effects of Cr concentrations, irradiation doses and irradiation temperatures on a' phase formation in Fe-Cr model alloys (10-16 at.%) irradiated at 300 and 450°C to 0.01, 0.1 and 1 dpa. For 1 dpa specimens, α' precipitates with an average radius of 1.0-1.3 nm were observed. The precipitate density varied significantly from 1.1x10²³ to 2.7x10²⁴ 1/m³, depending on Cr concentrations and irradiation temperatures. The volume fraction of α' phase in 1 dpa specimens qualitatively agreed with the phase diagram prediction. For 0.01 dpa and 0.1 dpa, frequency distribution analysis detected slight Cr segregation in high-Cr specimens, but not in Fe-10Cr specimens. Proximity histogram analysis showed that the radial Cr concentration was highest at the center of a' precipitates. For most precipitates, the Cr contents were significantly lower than that predicted by the phase diagram. The Cr concentration at precipitate center increased with increasing precipitate size.

  5. Response of 9Cr-ODS Steel to Proton Irradiation at 400 °C

    SciTech Connect (OSTI)

    Jianchao He; Farong Wan; Kumar Sridharan; Todd R. Allen; A. Certain; Y. Q. Wu

    2014-09-01

    The stability of Y–Ti–O nanoclusters, dislocation structure, and grain boundary segregation in 9Cr-ODS steels has been investigated following proton irradiation at 400 °C with damage levels up to 3.7 dpa. A slight coarsening and a decrease in number density of nanoclusters were observed as a result of irradiation. The composition of nanoclusters was also observed to change with a slight increase of Y and Cr concentration in the nanoclusters following irradiation. Size, density, and composition of the nanoclusters were investigated as a function of nanocluster size, specifically classified to three groups. In addition to the changes in nanoclusters, dislocation loops were observed after irradiation. Finally, radiation-induced enrichment of Cr and depletion of W were observed at grain boundaries after irradiation.

  6. Multiband Optical Absorption Controlled by Lattice Strain in Thin-Film LaCrO3

    SciTech Connect (OSTI)

    Sushko, Peter; Qiao, Liang; Bowden, Mark E.; Varga, Tamas; Exarhos, Gregory J.; Urban, III, Frank K.; Barton, David; Chambers, Scott A.

    2013-02-11

    Experimental measurements and ab initio modeling of the optical transitions in strained G-type antiferromagnetic LaCrO3 resolve two decades of debate regarding the magnitude of the optical band gap and the character of the corresponding transitions in this material. Using time-dependent density functional theory and accounting for thermal disorder effects, we demonstrate that the fourmost prominent low-energy absorption features are due to intra-Cr t2g {eg (2.4, 3.6 eV), inter-Crt2g {t2g (4.4 eV), and inter-ion O 2p { Cr 3d (from ?5 eV) transitions and show that the excitation energies of the latter type can be strongly affected by the lattice strain.

  7. Electronic and magnetic properties of epitaxial perovskite SrCrO3(001)

    SciTech Connect (OSTI)

    Zhang, Hongliang; Du, Yingge; Sushko, Petr; Bowden, Mark E.; Shutthanandan, V.; Qiao, Liang; Cao, Guixin; Gai, Zheng; Sallis, Shawn; Piper, L.F.J.; Chambers, Scott A.

    2015-06-24

    We have investigated the intrinsic properties of SrCrO3 epitaxial thin films synthesized by molecular beam epitaxy. We find compelling evidence that SrCrO3 is a correlated metal. X-ray photoemission valence band and O K-edge x-ray absorption spectra indicate a strongly hybridized Cr3d-O2p state crossing the Fermi level, leading to metallic behavior. Comparison between valence band spectra near the Fermi level and the densities of states calculated using density functional theory (DFT) also suggests the presence of coherent and incoherent states and points to a strong electron-electron correlation effects. The magnetic susceptibility can be described by Pauli paramagnetism at temperatures above 100 K, but reveals antiferromagnetic behavior at lower temperatures resulting from orbital ordering as suggested by Ortega-San-Martin et al. [Phys. Rev. Lett. 99, 255701 (2007)].

  8. Martensitic transformation behaviors of rapidly solidified TiNiMo powders

    SciTech Connect (OSTI)

    Kim, Yeon-wook

    2012-10-15

    For the fabrication of bulk near-net-shape shape memory alloys and porous metallic biomaterials, consolidation of TiNiMo alloy powders is more useful than that of elemental powders of Ti, Ni and Mo. Ti{sub 50}Ni{sub 49.9}Mo{sub 0.1} shape memory alloy powders were prepared by gas atomization, and transformation temperatures and microstructures of those powders were investigated as a function of powder size. XRD analysis showed that the B2RB19 martensitic transformation occurred in powders smaller than 150 ?m. According to DSC analysis of the as-atomized powders, the B2R transformation temperature (T{sub R}) of the 2550 ?m powders was 18.4 C. The T{sub R} decreased with increasing powder size, however, the difference in T{sub R} between 2550 ?m powders and 100150 ?m powders is only 1 C. Evaluation of powder microstructures was based on SEM examination of the surface and the polished and etched powder cross sections and the typical images of the rapidly solidified powders showed cellular morphology. Porous cylindrical foams of 10 mm diameter and 1.5 mm length were fabricated by spark plasma sintering (SPS) at 800 C and 5 MPa. Finally these porous TiNi alloy samples are heat-treated for 1 h at 850 C, and then quenched in ice water. The bulk samples have 23% porosity and 4.6 g/cm{sup 3} density and their T{sub R} is 17.8 C.

  9. FULL SIZE U-10MO MONOLITHIC FUEL FOIL AND FUEL PLATE FABRICATION-TECHNOLOGY DEVELOPMENT

    SciTech Connect (OSTI)

    G. A. Moore; J-F Jue; B. H. Rabin; M. J. Nilles

    2010-03-01

    Full-size U10Mo foils are being developed for use in high density LEU monolithic fuel plates. The application of a zirconium barrier layer too the foil is applied using a hot co-rolling process. Aluminum clad fuel plates are fabricated using Hot Isostatic Pressing (HIP) or a Friction Bonding (FB) process. An overview is provided of ongoing technology development activities, including: the co-rolling process, foil shearing/slitting and polishing, cladding bonding processes, plate forming, plate-assembly swaging, and fuel plate characterization. Characterization techniques being employed include, Ultrasonic Testing (UT), radiography, and microscopy.

  10. Pairing correlations and thermodynamical quantities in {sup 96,97}Mo

    SciTech Connect (OSTI)

    Kargar, Z.

    2007-06-15

    The nuclear level densities of {sup 96,97}Mo are calculated in the framework of superconducting theory. The parameters of nuclear level density are so chosen that the saddle point conditions are satisfied and the best fit to the experimental data yields. Then, using these parameters the energy, the entropy and the spin cut-off factor are calculated as a function of temperature. The curves show structures, reflecting the phase transition from a correlated to an uncorrelated phase. The critical temperature for quenching of pairing correlations is found at T{sub c}{approx}0.7-0.9 MeV.

  11. Hydrofining of Athabasca derived heavy gas oil over Ni-W and Co-Mo catalysts

    SciTech Connect (OSTI)

    Mann, R.S.; Diaz-real, R.

    1987-01-01

    The hydrotreatment of heavy gas oil derived from Athabasca bitumen was studied in a trickle bed reactor over Ni-W and Co-Mo zeolite catalyst at 350-425/sup 0/C, 3.55 to 10.44 MPa, and LHSV of 1-4. The effects of temperature and liquid flow rates on the product were investigated. ASTM distillation, aniline point, viscosities and densities of the product oil were measured and correlated with various parameters. Activity of the catalysts for hydrodenitrogenation is compared.

  12. Demonstration of a Full-core Reactivity Equivalence for FeCrAl Enhanced

    Office of Scientific and Technical Information (OSTI)

    Accident Tolerant Fuel in BWRs (Conference) | SciTech Connect Demonstration of a Full-core Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Citation Details In-Document Search Title: Demonstration of a Full-core Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Authors: George, Nathan M [1] ; Powers, Jeffrey J [1] ; Maldonado, G Ivan [1] ; Worrall, Andrew [1] ; Terrani, Kurt A [1] + Show Author Affiliations ORNL Publication Date: 2015-01-01

  13. Development of a Full-core Reactivity Equivalence for FeCrAl Enhanced

    Office of Scientific and Technical Information (OSTI)

    Accident Tolerant Fuel in BWRs (Conference) | SciTech Connect Development of a Full-core Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Citation Details In-Document Search Title: Development of a Full-core Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Authors: George, Nathan M [1] ; Powers, Jeffrey J [1] ; Maldonado, G Ivan [1] ; Worrall, Andrew [1] ; Terrani, Kurt A [1] + Show Author Affiliations ORNL Publication Date: 2015-01-01 OSTI

  14. Elastic Modulus Measurement of ORNL ATF FeCrAl Alloys

    SciTech Connect (OSTI)

    Thompson, Zachary T.; Terrani, Kurt A.; Yamamoto, Yukinori

    2015-10-01

    Elastic modulus and Poissons ratio for a number of wrought FeCrAl alloys, intended for accident tolerant fuel cladding application, are determined via resonant ultrasonic spectroscopy. The results are reported as a function of temperature from room temperature to 850C. The wrought alloys were in the fully annealed and unirradiated state. The elastic modulus for the wrought FeCrAl alloys is at least twice that of Zr-based alloys over the temperature range of this study. The Poissons ratio of the alloys was 0.28 on average and increased very slightly with increasing temperature.

  15. Development and quality assessments of commercial heat production of ATF FeCrAl tubes

    SciTech Connect (OSTI)

    Yamamoto, Yukinori

    2015-09-01

    Development and quality assessment of the 2nd generation ATF FeCrAl tube production with commercial manufacturers were conducted. The manufacturing partners include Sophisticated Alloys, Inc. (SAI), Butler, PA for FeCrAl alloy casting via vacuum induction melting, Oak Ridge National Laboratory (ORNL) for extrusion process to prepare the master bars/tubes to be tube-drawn, and Rhenium Alloys, Inc. (RAI), North Ridgeville, OH, for tube-drawing process. The masters bars have also been provided to Los Alamos National Laboratory (LANL) who works with Century Tubes, Inc., (CTI), San Diego, CA, as parallel tube production effort under the current program.

  16. The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via Reductive

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

    Labilization | Center for Gas SeparationsRelevant to Clean Energy Technologies | Blandine Jerome The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via Reductive Labilization Previous Next List Lian, Xizhen; Feng, Dawei; Chen, Ying-Pin; Liu, Tian-Fu; Wang, Xuan; and Zhou, Hong-Cai. The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via Reductive Labilization. Chem. Sci., 6, 7044-7048 (2015). DOI: 10.1039/c5sc02587g preparation.ultrastable Abstract: Kinetic labilization of the

  17. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect SciTech Connect Search Results Journal Article: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Citation Details In-Document Search Title: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Authors: Dhar, S. K. [1] ; Provino, A. [2] ; Manfrinetti, P. [2] ; Kulkarni, R. [1] ; Goyal, Neeraj [1] ; Paudyal, D. [3] + Show Author Affiliations Department of Condensed Matter Physics & Materials Science, T.I.F.R., Homi Bhabha Road, Colaba,

  18. AB INITIO PHASE STABILITY AT HIGH TEMPERATURES AND PRESSURES IN THE V-Cr

    Office of Scientific and Technical Information (OSTI)

    SYSTEM (Journal Article) | SciTech Connect AB INITIO PHASE STABILITY AT HIGH TEMPERATURES AND PRESSURES IN THE V-Cr SYSTEM Citation Details In-Document Search Title: AB INITIO PHASE STABILITY AT HIGH TEMPERATURES AND PRESSURES IN THE V-Cr SYSTEM Authors: Landa, A ; Soderlind, P ; Yang, L H Publication Date: 2013-10-29 OSTI Identifier: 1116979 Report Number(s): LLNL-JRNL-645443 DOE Contract Number: W-7405-ENG-48 Resource Type: Journal Article Resource Relation: Journal Name: Physical Review

  19. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | DOE PAGES Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Title: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Authors: Dhar, S. K. [1] ; Provino, A. [2] ; Manfrinetti, P. [2] ; Kulkarni, R. [1] ; Goyal, Neeraj [1] ; Paudyal, D. [3] + Show Author Affiliations Department of Condensed Matter Physics & Materials Science, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai, 400005, India Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146

  20. Uniform Corrosion of model FeCrAl Alloys in LWR Coolants (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Conference: Uniform Corrosion of model FeCrAl Alloys in LWR Coolants Citation Details In-Document Search Title: Uniform Corrosion of model FeCrAl Alloys in LWR Coolants Authors: Terrani, Kurt A [1] ; Kim, Young-Jin [2] ; Pint, Bruce A [1] + Show Author Affiliations ORNL General Electric (GE) Publication Date: 2015-01-01 OSTI Identifier: 1185956 DOE Contract Number: DE-AC05-00OR22725 Resource Type: Conference Resource Relation: Conference: 2015 American Nuclear Society Annual

  1. In Situ Time-Resolved Characterization of Novel Cu-MoO2 Catalysts During the Water-Gas Shift Reaction

    SciTech Connect (OSTI)

    Wen ,W.; Liu, J.; White, M.; Marinkovic, N.; Hanson, J.; Rodriguez, J.

    2007-01-01

    A novel and active Cu-MoO{sub 2} catalyst was synthesized by partial reduction of a precursor CuMoO{sub 4} mixed-metal oxide with CO or H{sub 2} at 200-250 C. The phase transformations of Cu-MoO{sub 2} during H{sub 2} reduction and the water-gas shift reaction could be followed by In situ time resolved XRD techniques. During the reduction process the diffraction pattern of the CuMoO{sub 4} collapsed and the copper metal lines were observed on an amorphous material background that was assigned to molybdenum oxides. During the first pass of water-gas shift (WGS) reaction, diffraction lines for Cu{sub 6}Mo{sub 5}O{sub 18} and MoO{sub 2} appeared around 350 C and Cu{sub 6}Mo{sub 5}O{sub 18} was further transformed to Cu/MoO{sub 2} at higher temperature. During subsequent passes, significant WGS catalytic activity was observed with relatively stable plateaus in product formation around 350, 400 and 500 C. The interfacial interactions between Cu clusters and MoO{sub 2} increased the water-gas shift catalytic activities at 350 and 400 C.

  2. Extraordinary selectivity of CoMo{sub 3}S{sub 13} chalcogel for C{sub 2}H{sub 6} and CO{sub 2} adsorption.

    SciTech Connect (OSTI)

    Shafaei-Fallah, M.; Rothenberger, Z.; Katsoulidis, A. P.; He, J.; Malliakas, C. D.; Kanatzidis, M. G.

    2011-11-09

    The chalcogel CoMo{sub 3}S{sub 13} is obtained from the reaction of (NH{sub 4}){sub 2}[Mo{sub 3}S{sub 13}] with cobalt acetate in solution. The chalcogel has a BET surface area of 570 m{sup 2} g{sup -1}, and pair distribution function analysis (PDF) and infrared spectroscopy indicate that the [Mo{sub 3}S{sub 13}]{sup 2-} cluster is a building block in the porous network. The CoMo{sub 3}S{sub 13} chalcogel exhibits high selectivity for separating ethane and carbon dioxide from hydrogen and methane.

  3. EPR and optical investigations of LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor

    SciTech Connect (OSTI)

    Singh, Vijay; Sivaramaiah, G.; Rao, J.L.; Kim, S.H.

    2014-12-15

    Graphical abstract: The EPR spectrum of as-prepared LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor at 110 K. - Highlights: • Using the combustion synthesis, LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared in a few minutes. • Optical investigation indicates that Cr{sup 3+} ions are present in octahedral symmetry. • The EPR signals indicate that exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs in weakly distorted sites. - Abstract: The LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared by a low-temperature combustion synthesis method. As-prepared combustion synthesized powder was characterized using powder X-ray diffraction (XRD), diffuse reflectance (DRS), electron paramagnetic resonance (EPR) and photoluminescence (PL) studies. The X-ray diffraction pattern reveals crystalline hexagonal phases. The UV–vis diffuse reflectance spectrum exhibits three broad bands characteristic of Cr{sup 3+} ions in octahedral symmetry. The EPR spectrum exhibits several resonance signals. The signals with the effective g values at g = 4.84, 3.64 and 2.26 have been attributed to the isolated Cr{sup 3+} ions. The signal with the effective g value at g = 1.94 has been attributed to exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs. The PL studies exhibit several bands characteristic of Cr{sup 3+} ions in octahedral symmetry.

  4. Dual and Triple Ion-Beam Irradiations of Fe, Fe(Cr) and Fe(Cr)-ODS Final Report: IAEA SMoRE CRP

    SciTech Connect (OSTI)

    Fluss, M J; Hsiung, L L; Marian, J

    2011-11-20

    Structures of nanoparticles in Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y2O3 (K3) and Fe-20Cr-4.5Al-0.34Ti-0.5Y2O3 (MA956) oxide dispersion strengthened (ODS) ferritic steels produced by mechanical alloying (MA) and followed by hot extrusion have been studied using high-resolution transmission electron microscopy (HRTEM) techniques to gain insight about the formation mechanism of nanoparticles in MA/ODS steels. The observations of Y-Al-O complex-oxide nanoparticles in both ODS steels imply that decomposition of Y2O3 in association with internal oxidation of Al occurred during mechanical alloying. While the majority of oxide nanoparticles formed in both steels is Y4Al2O9, a few oxide particles of YAlO3 are also occasionally observed. These results reveal that Ti (0.3 wt %) plays an insignificant role in forming oxide nanoparticles in the presence of Al (4.5 wt %). HRTEM observations of crystalline nanoparticles larger than {approx}2 nm and amorphous or disordered cluster domains smaller than {approx}2 nm provide an insight into the formation mechanism of oxide nanoparticle in MA/ODS steels, which we believe from our observations involves a solid-state amorphous precursor followed by recrystallization. Dual ion-beam irradiations using He{sup +} + Fe{sup +8} ions were employed to gain more detailed insight about the role of nanoparticles in suppressing radiation-induced swelling. This is elaborated through TEM examinations of cavity distributions in ion-irradiated Fe-14Cr and K3-ODS ferritic steels. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoscale oxide particles and clusters in ion-irradiated K3-ODS are presented. Finally, we describe the results from triple ion-beam irradiations using H{sup +} + He{sup +} + Fe{sup +8} ions to emulate fusion first wall radiation effects. Preliminary work is reported that confirms the existence of significant hydrogen synergistic effects described earlier by Tanaka et al., for Fe(Cr) and by Wakai et al., for F82H reduced activation ferritic martensitic (RAF/M) steel. These previous results combined with our data suggest a complex new 'catalytic' mechanism whereby H interacts with the steady state population of defects and the embryonic cavities so as to accelerated cavity (void) growth in both Fe(Cr) and under special conditions in ODS steels.

  5. Ab initio study of structural stability and electronic properties of Ti{sub 1-x}Mg{sub x}Cr{sub 2} and TiMg{sub x}Cr{sub 2-x} laves phase

    SciTech Connect (OSTI)

    Sari, A. Merad, G.

    2015-03-30

    The structural stability and electronic properties of TiMgCr{sub 2} laves phase have been calculated and compared. It is found that Mg prefer to substitutes titanium than chromium. The values of entalpies of formation show that Ti{sub 1-x}Mg{sub x}Cr{sub 2} may exist for only one concentration x=0.125 and the more favorable alloy is Ti{sub 0.875}Mg{sub 0.125}Cr{sub 2}. For TiCr{sub 2}, the optimized structural parameters were in good agreement with experimental values, while for TiMgCr{sub 2}, there is not experimental data. The electronic densities of states (DOS) are given and the nature of bonds are also discussed.

  6. On the bonding nature of electron states for the Fe-Mo double perovskite

    SciTech Connect (OSTI)

    Carvajal, E.; Cruz-Irisson, M.; Oviedo-Roa, R.; Navarro, O.

    2014-05-15

    The electronic transport as well as the effect of an external magnetic field has been investigated on manganese-based materials, spinels and perovskites. Potential applications of double perovskites go from magnetic sensors to electrodes in solid-oxide fuel cells; besides the practical interests, it is known that small changes in composition modify radically the physical properties of double perovskites. We have studied the Sr{sub 2}FeMoO{sub 6} double perovskite compound (SFMO) using first-principles density functional theory. The calculations were done within the generalized gradient approximation (GGA) scheme with the Perdew-Burke-Ernzerhof (PBE) functional. We have made a detailed analysis of each electronic state and the charge density maps around the Fermi level. For the electronic properties of SFMO it was used a primitive cell, for which we found the characteristic half-metallic behavior density of states composed by e{sub g} and t{sub 2g} electrons from Fe and Mo atoms. Those peaks were tagged as bonding or antibonding around the Fermi level at both, valence and conduction bands.

  7. Electronic structure and conductivity of nanocomposite metal (Au,Ag,Cu,Mo)-containing amorphous carbon films

    SciTech Connect (OSTI)

    Endrino, Jose L.; Horwat, David; Gago, Raul; Andersson, Joakim; Liu, Y.S.; Guo, Jinghua; Anders, Andre

    2008-05-14

    In this work, we study the influence of the incorporation of different metals (Me = Au, Ag, Cu, Mo) on the electronic structure of amorphous carbon (a-C:Me) films. The films were produced at room temperature using a novel pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas X-ray diffraction was used to identify the formation of metal nanoclusters in the carbon matrix. The metal content incorporated in the nanocomposite films induces a drastic increase in the conductivity, in parallel with a decrease in the band gap corrected from Urbach energy. The electronic structure as a function of the Me content has been monitored by x-ray absorption near edge structure (XANES) at the C K-edge. XANES showed that the C host matrix has a dominant graphitic character and that it is not affected significantly by the incorporation of metal impurities, except for the case of Mo, where the modifications in the lineshape spectra indicated the formation of a carbide phase. Subtle modifications of the spectral lineshape are discussed in terms of nanocomposite formation.

  8. Experimental study of the electric dipole strength in the even Mo nuclei and its deformation dependence

    SciTech Connect (OSTI)

    Erhard, M.; Junghans, A. R.; Nair, C.; Schwengner, R.; Beyer, R.; Klug, J.; Kosev, K.; Wagner, A.; Grosse, E.

    2010-03-15

    Two methods based on bremsstrahlung were applied to the stable even Mo isotopes for the experimental determination of the photon strength function covering the high excitation energy range above 4 MeV with its increasing level density. Photon scattering was used up to the neutron separation energies S{sub n} and data up to the maximum of the isovector giant resonance (GDR) were obtained by photoactivation. After a proper correction for multistep processes the observed quasicontinuous spectra of scattered photons show a remarkably good match to the photon strengths derived from nuclear photoeffect data obtained previously by neutron detection and corrected in absolute scale by using the new activation results. The combined data form an excellent basis to derive a shape dependence of the E1 strength in the even Mo isotopes with increasing deviation from the N=50 neutron shell (i.e., with the impact of quadrupole deformation and triaxiality). The wide energy coverage of the data allows for a stringent assessment of the dipole sum rule and a test of a novel parametrization developed previously which is based on it. This parametrization for the electric dipole strength function in nuclei with A>80 deviates significantly from prescriptions generally used previously. In astrophysical network calculations it may help to quantify the role the p-process plays in cosmic nucleosynthesis. It also has impact on the accurate analysis of neutron capture data of importance for future nuclear energy systems and waste transmutation.

  9. Spin and valley transport in monolayers of MoS{sub 2}

    SciTech Connect (OSTI)

    Sun, J. F.; Cheng, F.

    2014-04-07

    We investigate theoretically quantum transport and Goos-Hnchen (GH) effect of electrons in a p-n-p junction on monolayers of MoS{sub 2}. We find that the transmission properties of spin-up (spin-down) electrons in K valley are the same with spin-down (spin-up) electrons in K? valley due to the time-reversal symmetry. The GH shifts for the transmitted K and K? beams in the n-p interface are in the opposite direction, and GH shifts for the spin-up and spin-down electron beams at the same valley have different values in the same direction due to the different group velocities. Therefore, the spin-up and spin-down electrons can be separated after passing a sufficiently long channel created by a p-n-p junction. These features provide us a new way to generate a fully spin- and valley-polarized current in monolayers of MoS{sub 2}.

  10. Consent to Subcontracts on Management and Operating (M&O) Contracts

    Broader source: Energy.gov [DOE]

    This is to provide notice that an Acquisition Letter (AL) will be issued addressing the establishment of subcontract review thresholds on M&O contracts. Currently, DEAR 970.4401-1 and 970.4401-2 require Heads of the Contracting Activities (HCAs) to establish thresholds, by subcontract type and dollar level, for the review and approval of proposed subcontracting actions by each M&O contractor under their cognizance. The AL will seek to improve Consent to Subcontract efficiency and to ensure we apply our resources to those subcontract actions that truly pose the most risk. The AL will state that the HCA should determine appropriate tiers for subcontract review thresholds, as a result of a risk assessment. This tiered approach may result in different thresholds being established for different sites as well as different thresholds at a given site, taking into consideration the best interests of DOE and the following factors: approval status of the contractor's purchasing system results of Independent Peer Review Program for Contractors' Purchasing Systems (e.g., PERT results) results of Contractor Balanced Scorecard Self-assessment size, experience, ability, reliability, and organization of the contractor's purchasing function internal controls, procedures, and organizational stature of the contractor's purchasing function subcontract type (fixed price vs. cost reimbursement) degree of competition value nature of the work/complexity whether the subcontract needs special surveillance

  11. Raman shifts in electron-irradiated monolayer MoS2

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

    Parkin, William M.; Balan, Adrian; Liang, Liangbo; Das, Paul Masih; Lamparski, Michael; Naylor, Carl H.; Rodríguez-Manzo, Julio A.; Johnson, A. T. Charlie; Meunier, Vincent; Drndic, Marija

    2016-03-21

    Here, we report how the presence of electron-beam-induced sulfur vacancies affects first-order Raman modes and correlate the effects with the evolution of the in situ transmission-electron microscopy (TEM) two-terminal conductivity of monolayer MoS2 under electron irradiation. We observe a redshift in the E Raman peak and a less pronounced blueshift in the A'1 peak with increasing electron dose. Using energy-dispersive X-ray spectroscopy (EDS), we show that irradiation causes partial removal of sulfur and correlate the dependence of the Raman peak shifts with S vacancy density (a few %), which is confirmed by first-principles density functional theory calculations. In situ devicemore » current measurements show exponential decrease in channel current upon irradiation. Our analysis demonstrates that the observed frequency shifts are intrinsic properties of the defective systems and that Raman spectroscopy can be used as a quantitative diagnostic tool to characterize MoS2-based transport channels.« less

  12. Spectroscopic signatures of AA' and AB stacking of chemical vapor deposited bilayer MoS2

    SciTech Connect (OSTI)

    Xia, Ming; Li, Bo; Yin, Kuibo; Capellini, Giovanni; Niu, Gang; Gong, Yongji; Zhou, Wu; Ajayan, Pulickel M.; Xie, Ya -Hong

    2015-11-04

    We discuss prominent resonance Raman and photoluminescence spectroscopic differences between AA'and AB stacked bilayer molybdenum disulfide (MoS2) grown by chemical vapor deposition are reported. Bilayer MoS2 islands consisting of the two stacking orders were obtained under identical growth conditions. Also, resonance Raman and photoluminescence spectra of AA' and AB stacked bilayer MoS2 were obtained on Au nanopyramid surfaces under strong plasmon resonance. Both resonance Raman and photoluminescence spectra show distinct features indicating clear differences in interlayer interaction between these two phases. The implication of these findings on device applications based on spin and valley degrees of freedom.

  13. Understanding the solidification and microstructure evolution during CSC-MIG welding of FeCrB-based alloy

    SciTech Connect (OSTI)

    Sorour, A.A. Chromik, R.R. Gauvin, R. Jung, I.-H. Brochu, M.

    2013-12-15

    The present is a study of the solidification and microstructure of Fe28.2%Cr3.8%B1.5%Si1.5%Mn (wt.%) alloy deposited onto a 1020 plain carbon steel substrate using the controlled short-circuit metal inert gas welding process. The as-solidified alloy was a metal matrix composite with a hypereutectic microstructure. Thermodynamic calculation based on the ScheilGulliver model showed that a primary (Cr,Fe){sub 2}B phase formed first during solidification, followed by an eutectic formation of the (Cr,Fe){sub 2}B phase and a body-centered cubic Fe-based solid solution matrix, which contained Cr, Mn and Si. Microstructure analysis confirmed the formation of these phases and showed that the shape of the (Cr,Fe){sub 2}B phase was irregular plate. As the welding heat input increased, the weld dilution increased and thus the volume fraction of the (Cr,Fe){sub 2}B plates decreased while other microstructural characteristics were similar. - Highlights: We deposit FeCrB-based alloy onto plain carbon steel using the CSC-MIG process. We model the solidification behavior using thermodynamic calculation. As deposited alloy consists of (Cr,Fe){sub 2}B plates embedded in Fe-based matrix. We study the effect of the welding heat input on the microstructure.

  14. Changes induced in a ZnS:Cr-based electroluminescent waveguide structure by intrinsic near-infrared laser radiation

    SciTech Connect (OSTI)

    Vlasenko, N. A. Oleksenko, P. F.; Mukhlyo, M. A.; Veligura, L. I.

    2013-08-15

    The causes of changes that occur in a thin-film electroluminescent metal-insulator-semiconductor-insulator-metal waveguide structure based on ZnS:Cr (Cr concentration of {approx}4 Multiplication-Sign 10{sup 20} cm{sup -3}) upon lasing ({lambda} Almost-Equal-To 2.6 {mu}m) and that induce lasing cessation are studied. It is established that lasing ceases because of light-scattering inhomogeneities formed in the structure and, hence, optical losses enhance. The origin of the inhomogeneities and the causes of their formation are clarified by studying the surface topology and the crystal structure of constituent layers of the samples before and after lasing. The studies are performed by means of atomic force microscopy and X-ray radiography. It is shown that a substantial increase in the sizes of grains on the surface of the structure is the manifestation of changes induced in the ZnS:Cr film by recrystallization. Recrystallization is initiated by local heating by absorbed laser radiation in existing Cr clusters and quickened by a strong electric field (>1 MV cm{sup -1}). The changes observed in the ZnS:Cr film are as follows: the textured growth of ZnS crystallites, an increase in the content of Cr clusters, and the appearance of some CrS and a rather high ZnO content. Some ways for improving the stability of lasing in the ZnS:Cr-based waveguide structures are proposed.

  15. Imaging findings and pharmacokinetics of 111-indium ZME-018 monoclonal antibody (MoAb) in malignant melanoma

    SciTech Connect (OSTI)

    Murray, J.L.; Rosenblum, M.; Lamki, L.; Haynie, T.P.; Glenn, H.; Jahns, M.; Plager, C.; Hersh, E.M.; Unger, M.; Carlo, D.L.

    1985-05-01

    13 patients with metastatic melanoma were studied using 5 mCi of In-111 labeled MoAb ZME-018 which reacts with GP 240 melanoma-associated antigen. The MoAb was infused over 2 h at doses of 2.5 mg (5 pts), 5 mg (5 pts), and 10 mg (3 pts). Total body tomograms and planar spot views with region of interest analysis were performed at 4, 24 and 72 hours post infusion. No adverse side effects were noted. There was rapid distribution to spleen, bone, bone marrow, liver, and testes. Tumor sites could be visualized as early as 24 hours but were more easily seen at 72 hours when the background activity was less. 20 of 46 (43%) previously documented metastases were identified. More sites imaged with increasing concentrations of MoAB, I.E., 25% at 2.5 mg; 67% at 5 mg; 70% at 10 mg. Tumor localization occurred in a significant number of patients especially at MoAb doses above 2.5 mg. In two instances, uptake of 111-In occurred in previously undiagnosed sites. The pharmacokinetics of MoAb were analyzed at each dose level. At the 5 mg dose, the terminal phase half-life for 111-In in plasma was 24.5 +- 2.7 hours. The apparent volume of distribution (Vd) was 4.03 +- 5iota similar to the plasma value, and the calculated clearance rate for 111-In label was 0.0259 + 0.002 ml/kg/min. Mean urinary excretion of 111-In label was 8.7 +- 0.6% of the administered dose over 48 hours after administration. The calculated pharmacokinetic parameters were independent of antibody dose. ZME 018 was cleared more rapidly from plasma, compared to previous studies with P97 antimelanoma MoAb.

  16. Cr-doped TiSe2 - A layered dichalcogenide spin glass

    SciTech Connect (OSTI)

    Luo, Huixia; Tao, Jing; Krizan, Jason W.; Seibel, Elizabeth M.; Xie, Weiwei; Sahasrabudhe, Girija S.; Bergman, Susanna L.; Phelan, Brendan F.; Wang, Zhen; Zhang, Jiandi; Cava, R. J.

    2015-09-17

    We report the magnetic characterization of the Cr-doped layered dichalcogenide TiSe2. The temperature dependent magnetic susceptibilities are typical of those seen in geometrically frustrated insulating antiferromagnets. The Cr moment is close to the spin-only value, and the Curie–Weiss temperatures (θcw) are between –90 and –230 K. Freezing of the spin system, which is glassy, characterized by peaks in the ac and dc susceptibility and specific heat, does not occur until below T/θcw = 0.05. The CDW transition seen in the resistivity for pure TiSe2 is still present for 3% Cr substitution but is absent by 10% substitution, above which the materials are metallic and p-type. Structural refinements, magnetic characterization, and chemical considerations indicate that the materials are of the type Ti1–xCrxSe2-x/2 for 0 ≤ x ≤ 0.6.

  17. Zinc protects human peripheral blood lymphocytes from Cr(III)(phenanthroline){sub 3}-induced apoptosis

    SciTech Connect (OSTI)

    Sankaramanivel, Sundararaj; Rajaram, Anantanarayanan; Rajaram, Rama

    2010-03-15

    We have studied the effect of Cr(III)(phen){sub 3} [(tris(1,10-phenanthroline) chromium(III) chloride)] on lymphocytes in order to find out if metallothioneins (MTs) are produced in the process. We also investigated whether zinc pretreatment is able to protect cells from apoptosis reported to occur for this compound. Our results indicate that MT synthesis is induced by Cr(III)(phen){sub 3}, and it has been identified as the MT-3 isoform through RT-PCR which has not been reported earlier. By zinc pretreatment, this apoptosis is reversed as inferred from cytotoxicity studies, Annexin-V/PI staining, ethidium bromide/acridine orange staining and DNA fragmentation pattern and ultrastructural investigations using TEM and SEM. The zinc pretreatment reduces the amount of ROS produced by Cr(III)(phen){sub 3} . The MT-1a and 1b synthesized by zinc (also evidenced through RT-PCR experiments) is possibly able to scavenge ROS which is one of the early signaling molecules that lead to apoptosis. Zinc pretreatment also reverses the changes in downstream signaling events such as mitochondrial membrane potential, ATP levels and the activation of caspase-3. This is the first report on the induction of MT-3 in lymphocytes due to a metal stress or any other stimuli. Even though MT-3 is synthesized here, apoptosis still occurs due to ROS production on Cr(III)(phen){sub 3} exposure when the cells have not been primed with zinc.

  18. Investigation on growth and laser properties of GGG:(Nd,Cr) single crystals

    SciTech Connect (OSTI)

    Zhang; Lin; Liu; Liu; Zhu

    1986-04-04

    Investigation on the growth and laser properties of gadolinium gallium garnet crystal doped with neodymium and chromium is reported. As the segregation coefficient of Nd in GGG is less than 1 and that of Cr is greater than 1, a modified Czochralski method for growth is adopted in order to keep the dopants being uniform in the grown crystal.

  19. Ion irradiation testing and characterization of FeCrAl candidate alloys

    SciTech Connect (OSTI)

    Anderoglu, Osman; Aydogan, Eda; Maloy, Stuart Andrew; Wang, Yongqiang

    2014-10-29

    The Fuel Cycle Research and Development program’s Advanced Fuels Campaign has initiated a multifold effort aimed at facilitating development of accident tolerant fuels. This effort involves development of fuel cladding materials that will be resistant to oxidizing environments for extended period of time such as loss of coolant accident. Ferritic FeCrAl alloys are among the promising candidates due to formation of a stable Al₂O₃ oxide scale. In addition to being oxidation resistant, these promising alloys need to be radiation tolerant under LWR conditions (maximum dose of 10-15 dpa at 250 – 350°C). Thus, in addition to a number of commercially available alloys, nuclear grade FeCrAl alloys developed at ORNL were tested using high energy proton irradiations and subsequent characterization of irradiation hardening and damage microstructure. This report summarizes ion irradiation testing and characterization of three nuclear grade FeCrAl cladding materials developed at ORNL and four commercially available Kanthal series FeCrAl alloys in FY14 toward satisfying FCRD campaign goals.

  20. Computational discovery of ferromagnetic semiconducting single-layer CrSnTe3

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

    Zhuang, Houlong L.; Xie, Yu; Kent, P. R. C.; Ganesh, P.

    2015-07-06

    Despite many single-layer materials being reported in the past decade, few of them exhibit magnetism. Here we perform first-principles calculations using accurate hybrid density functional methods (HSE06) to predict that single-layer CrSnTe3 (CST) is a ferromagnetic semiconductor, with band gaps of 0.9 and 1.2 eV for the majority and minority spin channels, respectively. We determine the Curie temperature as 170 K, significantly higher than that of single-layer CrSiTe3 (90K) and CrGeTe3 (130 K). This is due to the enhanced ionicity of the Sn-Te bond, which in turn increases the superexchange coupling between the magnetic Cr atoms. We further explore themore » mechanical and dynamical stability and strain response of this single-layer material for possible epitaxial growth. Lastly, our study provides an intuitive approach to understand and design novel single-layer magnetic semiconductors for a wide range of spintronics and energy applications.« less

  1. Microstructures and Mechanical Properties of Compositionally Complex Co-free FeNiMnCr18 FCC Solid Solution Alloy

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

    Wu, Zhenggang; Bei, Hongbin

    2015-01-01

    Recently,a structurally-simplebutcompositionally-complex FeNiCoMnCr highentropyalloywasfoundto haveexcellentmechanicalproperties(e.g.,highstrengthandductility).Tounderstandthepotentialof using highentropyalloysasstructuralmaterialsforadvancednuclearreactorandpowerplants,itis necessary tohaveathoroughunderstandingoftheirstructuralstabilityandmechanicalpropertiesde- gradation underneutronirradiation.ThisrequiresustodevelopasimilarmodelalloywithoutCobe- cause materialwithCowillmakepost-neutron-irradiationtestingdifficult duetotheproductionofthe 60Co radioisotope.Toachievethisgoal,aFCC-structuredsingle-phasealloywithacompositionof FeNiMnCr18 wassuccessfullydeveloped.Thisnear-equiatomicFeNiMnCr18 alloy hasgoodmalleability and itsmicrostructurecanbecontrolledbythermomechanicalprocessing.Byrollingandannealing,the as-cast elongated-grained-microstructureisreplacedbyhomogeneousequiaxedgrains.Themechanical properties (e.g.,strengthandductility)oftheFeNiMnCr18 alloy arecomparabletothoseoftheequiatomic FeNiCoMnCr highentropyalloy.Bothstrengthandductilityincreasewithdecreasingdeformation temperature,withthelargestdifferenceoccurringbetween293and77K.Extensivetwin-bandswhich are bundlesofnumerousindividualtwinsareobservedwhenitistensile-fracturedat77K.Notwin bands aredetectedbyEBSDformaterialsdeformedat293Kandhigher.Theunusualtemperature-de- pendencies ofUTSanduniformelongationcouldbecausedbythedevelopmentofthedensetwin substructure, twin-dislocationinteractionsandtheinteractionsbetweenprimaryandsecondarytwin- ning systemswhichresultinamicrostructurerefinement andhencecauseenhancedstrainhardening and postponednecking.

  2. Comparison of Two Preparation Methods on Catalytic Activity and Selectivity of Ru-Mo/HZSM5 for Methane Dehydroaromatization

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

    Petkovic, Lucia M.; Ginosar, Daniel M.

    2014-01-01

    Catalytic performance of Mo/HZSM5 and Ru-Mo/HZSM5 catalysts prepared by vaporization-deposition of molybdenum trioxide and impregnation with ammonium heptamolybdate was analyzed in terms of catalyst activity and selectivity, nitrogen physisorption analyses, temperature-programmed oxidation of carbonaceous residues, and temperature-programmed reduction. Vaporization-deposition rendered the catalyst more selective to ethylene and coke than the catalyst prepared by impregnation. This result was assigned to lower interaction of molybdenum carbide with the zeolite acidic sites.

  3. Enhancing the photocurrent and photoluminescence of single crystal monolayer MoS{sub 2} with resonant plasmonic nanoshells

    SciTech Connect (OSTI)

    Sobhani, Ali [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Lauchner, Adam [Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States); Najmaei, Sina; Lou, Jun [Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Ayala-Orozco, Ciceron; Wen, Fangfang [Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Halas, Naomi J., E-mail: halas@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2014-01-20

    Monolayer molybdenum disulfide (MoS{sub 2}) produced by controlled vapor-phase synthesis is a commercially promising new two-dimensional material for optoelectronics because of its direct bandgap and broad absorption in the visible and ultraviolet regimes. By tuning plasmonic core-shell nanoparticles to the direct bandgap of monolayer MoS{sub 2} and depositing them sparsely (<1% coverage) onto the material's surface, we observe a threefold increase in photocurrent and a doubling of photoluminescence signal for both excitonic transitions, amplifying but not altering the intrinsic spectral response.

  4. Preparation and immunoreactivity of high specific activity indium-111-DTPA labeled monoclonal antibody (MoAb) using ultrapure indium-111

    SciTech Connect (OSTI)

    Zoghbi, S.S.; Neumann, R.D.; Gottschalk, A.

    1986-10-01

    The preparation of high-specific activity /sup 111/In-DTPA-MoAb without increasing the number of DTPA molecules per Ab was investigated. Instant thin layer chromatography was used to assay the relationship between labeling efficiencies and specific activities. With ultrapurified /sup 111/In, the specific activity of the radiolabeled MoAb approached the expected theoretic maximum of 100 muCi/microgram. The bioactivity of such high-specific activity preparation showed no degradation as measured by in vitro cell binding assay.

  5. MoO3 as combined hole injection layer and tapered spacer in combinatorial multicolor microcavity organic light emitting diodes

    SciTech Connect (OSTI)

    Liu, R.; Xu, Chun; Biswas, Rana; Shinar, Joseph; Shinar, Ruth

    2011-09-01

    Multicolor microcavity ({mu}C) organic light-emitting diode (OLED) arrays were fabricated simply by controlling the hole injection and spacer MoO{sub 3} layer thickness. The normal emission was tunable from {approx}490 to 640 nm and can be further expanded. A compact, integrated spectrometer with two-dimensional combinatorial arrays of {mu}C OLEDs was realized. The MoO{sub 3} yields more efficient and stable devices, revealing a new breakdown mechanism. The pixel current density reaches {approx}4 A/cm{sup 2} and a maximal normal brightness {approx}140 000 Cd/m{sup 2}, which improves photoluminescence-based sensing and absorption measurements.

  6. Preparation and structural study from neutron diffraction data of Pr{sub 5}Mo{sub 3}O{sub 16}

    SciTech Connect (OSTI)

    Martinez-Lope, M.J.; Alonso, J.A.; Sheptyakov, D.; Pomjakushin, V.

    2010-12-15

    The title compound has been prepared as polycrystalline powder by thermal treatments of mixtures of Pr{sub 6}O{sub 11} and MoO{sub 2} in air. In the literature, an oxide with a composition Pr{sub 2}MoO{sub 6} has been formerly described to present interesting catalytic properties, but its true stoichiometry and crystal structure are reported here for the first time. It is cubic, isostructural with CdTm{sub 4}Mo{sub 3}O{sub 16} (space group Pn-3n, Z=8), with a=11.0897(1) A. The structure contains MoO{sub 4} tetrahedral units, with Mo-O distances of 1.788(2) A, fully long-range ordered with PrO{sub 8} polyhedra; in fact it can be considered as a superstructure of fluorite (M{sub 8}O{sub 16}), containing 32 MO{sub 2} fluorite formulae per unit cell, with a lattice parameter related to that of cubic fluorite (a{sub f}=5.5 A) as a{approx}2a{sub f}. A bond valence study indicates that Mo exhibits a mixed oxidation state between 5+ and 6+ (perhaps accounting for the excellent catalytic properties). One kind of Pr atoms is trivalent whereas the second presents a mixed Pr{sup 3+}-Pr{sup 4+} oxidation state. The similarity of the XRD pattern with that published for Ce{sub 2}MoO{sub 6} suggests that this compound also belongs to the same structural type, with an actual stoichiometry Ce{sub 5}Mo{sub 3}O{sub 16}. -- Graphical Abstract: Formerly formulated as Pr{sub 2}MoO{sub 6}, the title compound is a cubic superstructure of fluorite (a=11.0897(1) A, space group Pn-3n) due to the long-range ordering of PrO{sub 8} scalenohedra and MoO{sub 4} tetrahedral units, showing noticeable shifts of the oxygen positions in order to provide a tetrahedral coordination for Mo ions. A mixed valence Mo{sup 5+}-Mo{sup 6+} is identified, which could account for the excellent catalytic properties of this material. Display Omitted

  7. Toward epitaxially grown two-dimensional crystal hetero-structures: Single and double MoS{sub 2}/graphene hetero-structures by chemical vapor depositions

    SciTech Connect (OSTI)

    Lin, Meng-Yu [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Chang, Chung-En [Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan (China); Wang, Cheng-Hung [Institute of Display, National Chiao-Tung University, Hsinchu, Taiwan (China); Su, Chen-Fung; Chen, Chi [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Lee, Si-Chen [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Lin, Shih-Yen, E-mail: shihyen@gate.sinica.edu.tw [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan (China)

    2014-08-18

    Uniform large-size MoS{sub 2}/graphene hetero-structures fabricated directly on sapphire substrates are demonstrated with layer-number controllability by chemical vapor deposition (CVD). The cross-sectional high-resolution transmission electron microscopy (HRTEM) images provide the direct evidences of layer numbers of MoS{sub 2}/graphene hetero-structures. Photo-excited electron induced Fermi level shift of the graphene channel are observed on the single MoS{sub 2}/graphene hetero-structure transistors. Furthermore, double hetero-structures of graphene/MoS{sub 2}/graphene are achieved by CVD fabrication of graphene layers on top of the MoS{sub 2}, as confirmed by the cross-sectional HRTEM. These results have paved the possibility of epitaxially grown multi-hetero-structures for practical applications.

  8. High reflectance-low stress Mo-Si multilayer reflective coatings

    DOE Patents [OSTI]

    Montcalm, Claude; Mirkarimi, Paul B.

    2000-01-01

    A high reflectance-low stress Mo-Si multilayer reflective coating particularly useful for the extreme ultraviolet (EUV) wavelength region. While the multilayer reflective coating has particular application for EUV lithography, it has numerous other applications where high reflectance and low stress multilayer coatings are utilized. Multilayer coatings having high near-normal incidence reflectance (R.gtoreq.65%) and low residual stress (.ltoreq.100 MPa) have been produced using thermal and non-thermal approaches. The thermal approach involves heating the multilayer coating to a given temperature for a given time after deposition in order to induce structural changes in the multilayer coating that will have an overall "relaxation" effect without reducing the reflectance significantly.

  9. Process for fabricating high reflectance-low stress Mo--Si multilayer reflective coatings

    DOE Patents [OSTI]

    Montcalm, Claude; Mirkarimi, Paul B.

    2001-01-01

    A high reflectance-low stress Mo--Si multilayer reflective coating particularly useful for the extreme ultraviolet (EUV) wavelength region. While the multilayer reflective coating has particular application for EUV lithography, it has numerous other applications where high reflectance and low stress multilayer coatings are utilized. Multilayer coatings having high near-normal incidence reflectance (R.gtoreq.65%) and low residual stress (.ltoreq.100 MPa) have been produced using thermal and non-thermal approaches. The thermal approach involves heating the multilayer coating to a given temperature for a given time after deposition in order to induce structural changes in the multilayer coating that will have an overall "relaxation" effect without reducing the reflectance significantly.

  10. UPDATE ON FRICTION BONDING OF MONOLITHIC U-MO FUEL PLATES

    SciTech Connect (OSTI)

    D. E. Burkes; N. P. Hallinan; J. M. Wight; M. D. Chapple

    2007-09-01

    Friction Bonding (FB), formerly referred to as Friction Stir Welding, is an alternative plate fabrication technique to encapsulate monolithic U-Mo fuel foils inside 6061-T6 aluminum alloy cladding. Over the past year, significant progress has been made in the area of FB, including improvements in tool material, tool design, process parameters, cooling capability and capacity and modeling, all of which improve and enhance the quality of fabricated fuel plates, reproducibility of the fabrication process and bond quality of the fuel plates. Details of this progress and how it relates to the observed improvements and enhancements are discussed. In addition, details on how these improvements have been implemented into the last two RERTR mini-plate irradiation campaigns are also discussed.

  11. H-point exciton transitions in bulk MoS{sub 2}

    SciTech Connect (OSTI)

    Saigal, Nihit; Ghosh, Sandip

    2015-05-04

    Reflectance and photoreflectance spectrum of bulk MoS{sub 2} around its direct bandgap energy have been measured at 12?K. Apart from spectral features due to the A and B ground state exciton transitions at the K-point of the Brillouin zone, one observes additional features at nearby energies. Through lineshape analysis the character of two prominent additional features are shown to be quite different from that of A and B. By comparing with reported electronic band structure calculations, these two additional features are identified as ground state exciton transitions at the H-point of the Brillouin zone involving two spin-orbit split valance bands. The excitonic energy gap at the H-point is 1.965?eV with a valance bands splitting of 185?meV. While at the K-point, the corresponding values are 1.920?eV and 205?meV, respectively.

  12. Insulator to correlated metal transition in V_1-xMo_xO_2

    SciTech Connect (OSTI)

    Klimczuk, Tomasz; Ronning, Filip; Holman, Katherine; Mcqueen, Tyrel M; Williams, Anthony J; Stephens, P W; Zandbergen, Henny W; Xu, Q; Cava, Robert J

    2009-01-01

    The change from metallic to insulating states is one of the most dramatic transitions that solids undergo on cooling or chemical doping. Many materials display this transition, but only a handful have the right combination of crystal structure and physical properties to serve as model systems. VO{sub 2} is one of those materials. Using Mo as a chemical dopant in VO{sub 2}, we find unanticipated phenomenology for both the electronic and structural characteristics of the resulting insulator to metal transition. The results support a complex, previously proposed scenario involving the coexistence of both electron repulsion and electron pairing for yielding an insulator in VO{sub 2}, but not simply; many issues are raised about local versus itinerant behavior and structure-property correlations in this most iconic ofdoped correlated electron systems.

  13. Microstructural Characterization of Irradiated U-7Mo/Al-5Si Dispersion to High Fission Density

    SciTech Connect (OSTI)

    J. Gan; B. D. Miller; D. D. Keiser, Jr.; A. B. Robinson; J. W. Madden; P. G. Medvedev; D. M. Wachs

    2014-11-01

    The fuel development program for research and test reactors calls for improved knowledge on the effect of microstructure on fuel performance in reactors. This work summarizes the recent TEM microstructural characterization of an irradiated U-7Mo/Al-5Si dispersion fuel plate (R3R050) irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory to 5.21021 fissions/cm3. While a large fraction of the fuel grains is decorated with large bubbles, there is no evidence showing interlinking of these large bubbles at the specified fission density. The attachment of solid fission product precipitates to the bubbles is likely the result of fission product diffusion into these bubbles. The process of fission gas bubble superlattice collapse appears through bubble coalescence. The results are compared with the previous TEM work of the dispersion fuels irradiated to lower fission density from the same fuel plate.

  14. Extreme ultraviolet spectra of highly ionized Ge, Kr and Mo emitted by imploding plasmas

    SciTech Connect (OSTI)

    Goldsmith, S.; Feldman, U.; Cohen, L.; Behring, W.E.

    1984-01-01

    Spectra of highly ionized Ge, Kr and Mo in the spectral region of 10 to 80A were excited in laser-produced plasmas. The plasma was obtained by focusing the energy of the 24 laser beams of the University of Rochester Omega system on 0.4 mm diameter microballoon targets. The laser pulse duration was in the range of 0.87 to 1.09 ns, with total energy in the range of 1.8 to 2.2 kJ. The observed spectral lines include n = 2-2 transitions in the oxygen and fluorine isoelectronic sequences and n = 3 to 4 transitions in the sodium, magnesium and aluminum isoelectronic sequences. The present observations are compared with previous experimental and theoretical studies.

  15. Intense femtosecond photoexcitation of bulk and monolayer MoS{sub 2}

    SciTech Connect (OSTI)

    Paradisanos, I.; Fotakis, C.; Kymakis, E.; Kioseoglou, G.; Stratakis, E.

    2014-07-28

    The effect of femtosecond laser irradiation on bulk and single-layer MoS{sub 2} on silicon oxide is studied. Optical, field emission scanning electron microscopy and Raman microscopy were used to quantify the damage. The intensity of A{sub 1g} and E{sub 2g}{sup 1} vibrational modes was recorded as a function of the number of irradiation pulses. The observed behavior was attributed to laser-induced bond breaking and subsequent atoms removal due to electronic excitations. The single-pulse optical damage threshold was determined for the monolayer and bulk under 800?nm and 1030?nm pulsed laser irradiation, and the role of two-photon versus one photon absorption effects is discussed.

  16. High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors

    SciTech Connect (OSTI)

    Wallez, Gilles; Raison, Philippe E.; Smith, Anna L.; Clavier, Nicolas

    2014-07-01

    Dicesium molybdate (Cs{sub 2}MoO{sub 4})'s thermal expansion and crystal structure have been investigated herein by high temperature X ray diffraction in conjunction with Raman spectroscopy. This first crystal-chemical insight at high temperature is aimed at predicting the thermostructural and thermomechanical behavior of this oxide formed by the accumulation of Cs and Mo fission products at the periphery of nuclear fuel rods in sodium-cooled fast reactors. Within the temperature range of the fuel's rim, Cs{sub 2}MoO{sub 4} becomes hexagonal P6{sub 3}/mmc, with disordered MoO{sub 4} tetrahedra and 2D distribution of CsO bonds that makes thermal axial expansion both large (50??{sub l}?70 10{sup ?6} C{sup ?1}, 500800 C) and highly anisotropic (?{sub c}??{sub a}=6710{sup ?6} C{sup ?1}, hexagonal form). The difference with the fuel's expansion coefficient is of potential concern with respect to the cohesion of the Cs{sub 2}MoO{sub 4} surface film and the possible release of cesium radionuclides in accidental situations. - Graphical abstract: The weakness of the CsO bonds and the disordering of the MoO{sub 4} tetrahedra array in the high-temperature form are responsible for the huge thermal expansion of Cs{sub 2}MoO{sub 4} along the c-axis. - Highlights: Thermomechanical behavior of Cs{sub 2}MoO{sub 4} fission products compound is studied. High-temperature form of Cs{sub 2}MoO{sub 4} is characterized by XRD and Raman. Thermal expansion appears very high and anisotropic. Cohesion between Cs{sub 2}MoO{sub 4} and nuclear fuel seems questionable, and Cs release is expected.

  17. Role of Si on the Diffusional Interactions between U-Mo and Al-Si Alloys at 823 K (550 degrees C)

    SciTech Connect (OSTI)

    E. Perez; Y.H. Sohn; D.D. Keiser, Jr.

    2013-01-01

    U-Mo dispersions in Al-alloy matrix and monolithic fuels encased in Al-alloy are under development to fulfill the requirements for research and test reactors to use low-enriched molybdenum stabilized uranium alloys fuels. Significant interaction takes place between the U-Mo fuel and Al during manufacturing and in-reactor irradiation. The interactions products are Al-rich phases with physical and thermal characteristics that adversely affect fuel performance and lead to premature failure. Detailed analysis of the interdiffusion and microstructural development of this system was carried through diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo in contact with pure Al, Al-2wt.%Si, and Al-5wt.%Si, annealed at 823K for 1, 5 and 20 hours. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed for the analysis. Diffusion couples consisting of U-Mo vs. pure Al contained UAl3, UAl4, U6Mo4Al43, and UMo2Al20 phases. The addition of Si to the Al significantly reduced the thickness of the interdiffusion zone. The interdiffusion zones developed Al and Si enriched regions, whose locations and size depended on the Si and Mo concentrations in the terminal alloys. In the couples, the (U,Mo)(Al,Si)3 phase was observed throughout interdiffusion zone, and the U6Mo4Al43 and UMo2Al20 phases were observed only where the Si concentrations were low.

  18. Irradiation Performance of U-Mo Alloy Based ‘Monolithic’ Plate-Type Fuel – Design Selection

    SciTech Connect (OSTI)

    A. B. Robinson; G. S. Chang; D. D. Keiser, Jr.; D. M. Wachs; D. L. Porter

    2009-08-01

    A down-selection process has been applied to the U-Mo fuel alloy based monolithic plate fuel design, supported by irradiation testing of small fuel plates containing various design parameters. The irradiation testing provided data on fuel performance issues such as swelling, fuel-cladding interaction (interdiffusion), blister formation at elevated temperatures, and fuel/cladding bond quality and effectiveness. U-10Mo (wt%) was selected as the fuel alloy of choice, accepting a somewhat lower uranium density for the benefits of phase stability. U-7Mo could be used, with a barrier, where the trade-off for uranium density is critical to nuclear performance. A zirconium foil barrier between fuel and cladding was chosen to provide a predictable, well-bonded, fuel-cladding interface, allowing little or no fuel-cladding interaction. The fuel plate testing conducted to inform this selection was based on the use of U-10Mo foils fabricated by hot co-rolling with a Zr foil. The foils were subsequently bonded to Al-6061 cladding by hot isostatic pressing or friction stir bonding.

  19. Modification of polymer velvet cathode via metallic Mo coating for enhancement of high-current electron emission performances

    SciTech Connect (OSTI)

    Xiong, Ying; Wang, Bing; Yi, Yong; Xia, Liansheng; Zhang, Huang

    2013-09-15

    The effect of surface Mo coating on the high-current electron emission performances for polymer velvet cathode has been investigated in a diode with A-K gap of 11.5 cm by the combination of time-resolved electrical diagnostic and temporal pressure variation. Compared with uncoated polymer velvet cathode under the single-pulsed emission mode, the Mo-coated one shows lower outgassing levels (?0.40 Pa L), slower cathode plasma expansion velocity (?2.30 cm/?s), and higher emission stability as evidences by the change in cathode current, temporal pressure variation, and diode perveance. Moreover, after Mo coating, the emission consistency of the polymer velvet cathode between two adjacent pulses is significantly improved in double-pulsed emission mode with ?500 ns interval between two pulses, which further confirms the effectiveness of Mo coating for enhancement of electron emission performance of polymer velvet cathodes. These results should be of interest to the high-repetitive high-power microwave systems with cold cathodes.

  20. Concept Feasibility Report for Using Co-Extrusion to Bond Metals to Complex Shapes of U-10Mo

    SciTech Connect (OSTI)

    Lavender, Curt A.; Paxton, Dean M.; Smith, Mark T.; Soulami, Ayoub; Joshi, Vineet V.; Burkes, Douglas

    2013-12-30

    In support of the Convert Program of the U.S. Department of Energys National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative (GTRI), Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate fuel for the U.S. high-performance research reactors (USHPRR). This report documents the results of PNNLs efforts to develop the extrusion process for this concept. The approach to the development of a co-extruded complex-shaped fuel has been described and an extrusion of DU-10Mo was made. The initial findings suggest that given the extrusion forces required for processing U-10Mo, the co-extrusion process can meet the production demands of the USHPRR fuel and may be a viable production method. The development activity is in the early stages and has just begun to identify technical challenges to address details such as dimensional tolerances and shape control. New extrusion dies and roll groove profiles have been developed and will be assessed by extrusion and rolling of U-10Mo during the next fiscal year. Progress on the development and demonstration of the co-extrusion process for flat and shaped fuel is reported in this document

  1. Development and validation of capabilities to measure thermal properties of layered monolithic U-Mo alloy plate-type fuel

    SciTech Connect (OSTI)

    Burkes, Douglas; Casella, Andrew M.; Buck, Edgar C.; Casella, Amanda J.; Edwards, Matthew K.; MacFarlan, Paul J.; Pool, Karl N.; Smith, Frances N.; Steen, Franciska H.

    2014-07-19

    The uranium-molybdenum (U-Mo) alloy in a monolithic form has been proposed as one fuel design capable of converting some of the worlds highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of thermal conductivity behavior of the fuel system as a function of temperature and expected irradiation conditions. The purpose of this paper is to verify and validate the functionality of equipment methods installed in hot cells for eventual measurements on irradiated uranium-molybdenum (U-Mo) monolithic fuel specimens, procedures to operate the equipment, and models to extract the desired thermal properties. The results presented here demonstrate the adequacy of the equipment, procedures and models that have been developed for this purpose based on measurements conducted on surrogate depleted uranium-molybdenum (DU-Mo) alloy samples containing a zirconium diffusion barrier and clad in aluminum alloy 6061 (AA6061). The results are in excellent agreement with thermal property data reported in the literature for similar U-Mo alloys as a function of temperature.

  2. Thermomechanical process optimization of U-10wt% Mo Part 2: The effect of homogenization on the mechanical properties and microstructure

    SciTech Connect (OSTI)

    Joshi, Vineet V.; Nyberg, Eric A.; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas E.

    2015-07-09

    Low-enriched uranium alloyed with 10 wt% molybdenum (U-10Mo) is currently being investigated as an alternative fuel for the highly enriched uranium used in several of the United States high performance research reactors. Development of the methods to fabricate the U-10Mo fuel plates is currently underway and requires fundamental understanding of the mechanical properties at the expected processing temperatures. In the first part of this series, it was determined that the as-cast U-10Mo had a dendritic microstructure with chemical inhomogeneity and underwent eutectoid transformation during hot compression testing. In the present (second) part of the work, the as-cast samples were heat treated at several temperatures and times to homogenize the Mo content. Like the previous as-cast material, the homogenized materials were then tested under compression between 500 and 800C. The as-cast samples and those treated at 800C for 24 hours had grain sizes of 25-30 ?m, whereas those treated at 1000C for 16 hours had grain sizes around 250 ?m before testing. Upon compression testing, it was determined that the heat treatment had effects on the mechanical properties and the precipitation of the lamellar phase at sub-eutectoid temperatures.

  3. The photocatalysis of Bi{sub 2}MoO{sub 6} under the irradiation of blue LED

    SciTech Connect (OSTI)

    Sun, Yuanyuan; Wang, Wenzhong Zhang, Ling; Sun, Songmei

    2013-10-15

    Graphical abstract: - Highlights: • ·OH trap and hole sink were involved to investigate the active radicals. • Holes play a more important role in the degradation of RhB. • The ·OH were related to the decomposition of phenol. • The ·O{sub 2}-played a leading role in the photodegradation of phenol. • Blue LED is competitive and promising alternative for the future application. - Abstract: Bi{sub 2}MoO{sub 6} has been reported as a promising photocatalyst in wastewater treatment. The active radicals generated over the Bi{sub 2}MoO{sub 6} during the photocatalytic process were thought to be hydroxyl radical (·OH) but have not been proved. Herein, Bi{sub 2}MoO{sub 6} with nanoplate like morphology was synthesized and its photocatalytic performances in the degradation of rhodamine B (RhB) and phenol as colored and colorless model pollutants respectively were evaluated under the irradiation of blue light emitting diode (LED). The tert-butyl alcohol (TBA) as a ·OH trap and ethylene diamine tetraacetic acid (EDTA) as a hole sink were involved to investigate the main active groups that are generated on Bi{sub 2}MoO{sub 6} and function during the photodegradation of RhB and phenol. In addition, it is a competitive and promising alternative plan to use blue LED as light source for the future practical application in environmental remediation.

  4. Mesoporous carbon-containing MoS{sub 2} materials formed from the in situ decomposition of tetraalkylammonium thiomolybdates

    SciTech Connect (OSTI)

    Alonso, Gabriel; Berhault, Gilles; Paraguay, Francisco; Rivera, Eric; Fuentes, Sergio; Chianelli, Russell R

    2003-05-26

    Molybdenum disulfide with unique mesoporous structure was synthesized from tetraalkylammonium thiometallate precursors in situ decomposed in a batch reactor in the presence of dibenzothiophene (DBT). The precursors used in this study were tetraalkylammonium thiomolybdates with alkyl groups ranging from propyl to octyl. Molybdenum disulfide thus prepared presents high surface area (from 255 up to 329 m{sup 2}/g), high content of carbon (C/Mo=2.7-4.0) and type IV nitrogen adsorption-desorption isotherms when decomposed from tetrahexyl-, tetraheptyl- or tetraoctylammonium thiomolybdates. The as-formed materials are poorly crystallized with a very weak intensity of the (0 0 2) peak of the 2H-MoS{sub 2} structure. Such diffraction patterns are characteristic of exfoliated samples. Characterization by TEM shows a disordered layered structure with no long range order for the MoS{sub 2} catalysts. Therefore, the nature of the alkyl group in the precursor affects both the surface area and the pore size distribution of the final MoS{sub 2} catalysts with a progressive morphological modification up to a mesoporous organization.

  5. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    SciTech Connect (OSTI)

    Susmikanti, Mike; Sulistyo, Jos

    2014-09-30

    Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to develop code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix.

  6. NUMERICAL SIMULATION FOR MECHANICAL BEHAVIOR OF U10MO MONOLITHIC MINIPLATES FOR RESEARCH AND TEST REACTORS

    SciTech Connect (OSTI)

    Hakan Ozaltun & Herman Shen

    2011-11-01

    This article presents assessment of the mechanical behavior of U-10wt% Mo (U10Mo) alloy based monolithic fuel plates subject to irradiation. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Identification of the stress/strain characteristics is important for understanding the in-reactor performance of these plate-type fuels. For this work, three distinct cases were considered: (1) fabrication induced residual stresses (2) thermal cycling of fabricated plates; and finally (3) transient mechanical behavior under actual operating conditions. Because the temperatures approach the melting temperature of the cladding during the fabrication and thermal cycling, high temperature material properties were incorporated to improve the accuracy. Once residual stress fields due to fabrication process were identified, solution was used as initial state for the subsequent simulations. For thermal cycling simulation, elasto-plastic material model with thermal creep was constructed and residual stresses caused by the fabrication process were included. For in-service simulation, coupled fluid-thermal-structural interaction was considered. First, temperature field on the plates was calculated and this field was used to compute the thermal stresses. For time dependent mechanical behavior, thermal creep of cladding, volumetric swelling and fission induced creep of the fuel foil were considered. The analysis showed that the stresses evolve very rapidly in the reactor. While swelling of the foil increases the stress of the foil, irradiation induced creep causes stress relaxation.

  7. Four-point Bend Testing of Irradiated Monolithic U-10Mo Fuel

    SciTech Connect (OSTI)

    Rabin, B. H.; Lloyd, W. R.; Schulthess, J. L.; Wright, J. K.; Lind, R. P.; Scott, L.; Wachs, K. M.

    2015-03-01

    This paper presents results of recently completed studies aimed at characterizing the mechanical properties of irradiated U-10Mo fuel in support of monolithic base fuel qualification. Mechanical properties were evaluated in four-point bending. Specimens were taken from fuel plates irradiated in the RERTR-12 and AFIP-6 Mk. II irradiation campaigns, and tests were conducted in the Hot Fuel Examination Facility (HFEF) at Idaho National Laboratory (INL). The monolithic fuel plates consist of a U-10Mo fuel meat covered with a Zr diffusion barrier layer fabricated by co-rolling, clad in 6061 Al using a hot isostatic press (HIP) bonding process. Specimens exhibited nominal (fresh) fuel meat thickness ranging from 0.25 mm to 0.64 mm, and fuel plate average burnup ranged from approximately 0.4 x 1021 fissions/cm3 to 6.0 x 1021 fissions/cm3. After sectioning the fuel plates, the 6061 Al cladding was removed by dissolution in concentrated NaOH. Pre- and post-dissolution dimensional inspections were conducted on test specimens to facilitate accurate analysis of bend test results. Four-point bend testing was conducted on the HFEF Remote Load Frame at a crosshead speed of 0.1 mm/min using custom-designed test fixtures and calibrated load cells. All specimens exhibited substantially linear elastic behavior and failed in a brittle manner. The influence of burnup on the observed slope of the stress-strain curve and the calculated fracture strength is discussed.

  8. Development of an energy-use estimation methodology for the revised Navy Manual MO-303

    SciTech Connect (OSTI)

    Richman, E.E.; Keller, J.M.; Wood, A.G.; Dittmer, A.L.

    1995-01-01

    The U.S. Navy commissioned Pacific Northwest Laboratory (PNL) to revise and/or update the Navy Utilities Targets Manual, NAVFAC MO-303 (U.S. Navy 1972b). The purpose of the project was to produce a current, applicable, and easy-to-use version of the manual for use by energy and facility engineers and staff at all Navy Public Works Centers (PWCs), Public Works Departments (PWDs), Engineering Field Divisions (EFDs), and other related organizations. The revision of the MO-303 manual involved developing a methodology for estimating energy consumption in buildings and ships. This methodology can account for, and equitably allocate, energy consumption within Navy installations. The analyses used to develop this methodology included developing end-use intensities (EUIs) from a vast collection of Navy base metering and billing data. A statistical analysis of the metering data, weather data, and building energy-use characteristics was used to develop appropriate EUI values for use at all Navy bases. A complete Navy base energy reconciliation process was also created for use in allocating all known energy consumption. Initial attempts to use total Navy base consumption values did not produce usable results. A parallel effort using individual building consumption data provided an estimating method that incorporated weather effects. This method produced a set of building EUI values and weather adjustments for use in estimating building energy use. A method of reconciling total site energy consumption was developed based on a {open_quotes}zero-sum{close_quotes} principle. This method provides a way to account for all energy use and apportion part or all of it to buildings and other energy uses when actual consumption is not known. The entire text of the manual was also revised to present a more easily read understood and usable document.

  9. Analysis of the FeCrAl Accident Tolerant Fuel Concept Benefits during BWR Station Blackout Accidents

    SciTech Connect (OSTI)

    Robb, Kevin R

    2015-01-01

    Iron-chromium-aluminum (FeCrAl) alloys are being considered for fuel concepts with enhanced accident tolerance. FeCrAl alloys have very slow oxidation kinetics and good strength at high temperatures. FeCrAl could be used for fuel cladding in light water reactors and/or as channel box material in boiling water reactors (BWRs). To estimate the potential safety gains afforded by the FeCrAl concept, the MELCOR code was used to analyze a range of postulated station blackout severe accident scenarios in a BWR/4 reactor employing FeCrAl. The simulations utilize the most recently known thermophysical properties and oxidation kinetics for FeCrAl. Overall, when compared to the traditional Zircaloy-based cladding and channel box, the FeCrAl concept provides a few extra hours of time for operators to take mitigating actions and/or for evacuations to take place. A coolable core geometry is retained longer, enhancing the ability to stabilize an accident. Finally, due to the slower oxidation kinetics, substantially less hydrogen is generated, and the generation is delayed in time. This decreases the amount of non-condensable gases in containment and the potential for deflagrations to inhibit the accident response.

  10. Solute redistribution and phase stability at FeCr/TiO2–x interfaces under ion irradiation

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

    Xu, Y.; Aguiar, J. A.; Yadav, S. K.; Anderoglu, O.; Baldwin, J. K.; Wang, Y. Q.; Valdez, James A.; Misra, A.; Luo, H. M.; Uberuaga, B. P.; et al

    2015-02-26

    Cr diffusion in trilayer thin films of 100 nm Fe–18Cr/125 nm TiO2–x/100 nm Fe–18Cr deposited on MgO substrates at 500 °C was studied by either annealing at 500 °C or Ni3+ ion irradiation at 500 °C. Microchemistry and microstructure evolution at the metal/oxide interfaces were investigated using (high-resolution) transmission electron microscopy, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy. Diffusion of Cr into the O-deficient TiO2 layer, with negligible segregation to the FeCr/TiO2–x interface itself, was observed under both annealing and irradiation. Cr diffusion into TiO2–x was enhanced in ion-irradiated samples as compared to annealed. Irradiation-induced voids and amorphization ofmore » TiO2–x was also observed. The experimental results are rationalized using first-principles calculations that suggest an energetic preference for substituting Ti with Cr in sub-stoichiometric TiO2. Furthermore, the implications of these results on the irradiation stability of oxide-dispersed ferritic alloys are discussed.« less

  11. Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single

    Office of Scientific and Technical Information (OSTI)

    crystal (Journal Article) | SciTech Connect Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal Citation Details In-Document Search Title: Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal We have studied the anisotropic magnetic behavior of the rare earth intermetallic compound Dy{sub 6}Cr{sub 4}Al{sub 43}. This compound crystallizes in the hexagonal symmetry and orders ferromagnetically at 8.3 K as confirmed by the magnetic

  12. Partial substitution of Mo{sup 6+} by S{sup 6+} in the fast oxide ion conductor La{sub 2}Mo{sub 2}O{sub 9}: Synthesis, structure and sulfur depletion

    SciTech Connect (OSTI)

    Mhadhbi, Noureddine; Corbel, Gwenaeel; Lacorre, Philippe; Bulou, Alain

    2012-06-15

    Powder-solid state reaction route using La{sub 2}(SO{sub 4}){sub 3} as sulfur source was used to prepare compositions of the solid solution La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9}. Single phases were only obtained in the substitution range extending up to y=0.8 (40 mol% S) at the annealing temperature of 850 Degree-Sign C with regard to the limit of stability of the lanthanum sulphate reactant. Within the synthesis conditions, a stabilization of the high temperature {beta}-form is observed from and above y=0.1 (5 mol% S). Temperature-controlled X-ray diffraction and thermogravimetric analyses have shown that La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders undergo thermal decompositions in two steps. Heating above 900 Degree-Sign C, a sulfur depletion to the benefit of molybdenum in La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders leads to the formation of La{sub 2}SO{sub 6}. At higher temperature, the exsolved La{sub 2}SO{sub 6} phase then decomposes into La{sub 2}O{sub 3}, which in turn reacts with the sulfur-depleted La{sub 2}Mo{sub 2}O{sub 9} phase to form La{sub 2}MoO{sub 6}. The present study also reveals that depending on the substitution rate y, the sulfur depletion can be induced by ball-milling of raw powders. Along the La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} series, the isovalent substitution of molybdenum by sulfur tends to restrict in magnitude, or even to suppress above 400 Degree-Sign C, the distortive thermal expansion of the cubic {beta}-type structure, thus strongly decreasing the conductance at high temperature. - Graphical abstract: La{sub 2}O{sub 3}-MoO{sub 3}-'SO{sub 3}' ternary phase diagram showing the exsolution path at low temperature (white arrows) and the total decomposition path at high temperature (black arrows) of {beta}-La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders. Highlights: Black-Right-Pointing-Pointer Isovalent substitution of molybdenum by sulfur in La{sub 2}Mo{sub 2}O{sub 9} up to 40 mol%. Black-Right-Pointing-Pointer Stabilization of the {beta}-form for a sulfur content greater than or equal to 5 mol%. Black-Right-Pointing-Pointer Decomposition by sulfur exsolution induced by thermal treatment or ball-milling. Black-Right-Pointing-Pointer Reduction or even cancellation of the distortive thermal expansion above 400 Degree-Sign C. Black-Right-Pointing-Pointer Decrease of conductance at high T involved by the low thermal expansion above 400 Degree-Sign C.

  13. Néel temperature of Cr{sub 2}O{sub 3} in Cr{sub 2}O{sub 3}/Co exchange-coupled system: Effect of buffer layer

    SciTech Connect (OSTI)

    Pati, Satya Prakash E-mail: phy-satya@yahoo.co.in; Shimomura, Naoki; Nozaki, Tomohiro; Sahashi, Masashi; Shibata, Tatsuo

    2015-05-07

    The lattice parameter dependence of the Néel temperature T{sub N} of thin Cr{sub 2}O{sub 3} in a Cr{sub 2}O{sub 3}/Co exchange-coupled system is investigated. Lattice-mismatch-induced strain is generated in Cr{sub 2}O{sub 3} by using different buffer layers. The lattice parameters are determined from out-of-plane and in-plane X-ray diffraction measurements. The Néel temperature is detected by direct temperature-dependent magnetization measurement as well as the temperature-dependent interface exchange coupling energy. It is observed that in-plane lattice contraction can enhance T{sub N} in Cr{sub 2}O{sub 3}, which is consistent with theoretical calculations.

  14. Scaling Effects of Cr(VI) Reduction Kinetics. The Role of Geochemical Heterogeneity

    SciTech Connect (OSTI)

    Wang, Li; Li, Li

    2015-10-22

    The natural subsurface is highly heterogeneous with minerals distributed in different spatial patterns. Fundamental understanding of how mineral spatial distribution patterns regulate sorption process is important for predicting the transport and fate of chemicals. Existing studies about the sorption was carried out in well-mixed batch reactors or uniformly packed columns, with few data available on the effects of spatial heterogeneities. As a result, there is a lack of data and understanding on how spatial heterogeneities control sorption processes. In this project, we aim to understand and develop modeling capabilities to predict the sorption of Cr(VI), an omnipresent contaminant in natural systems due to its natural occurrence and industrial utilization. We systematically examine the role of spatial patterns of illite, a common clay, in determining the extent of transport limitation and scaling effects associated with Cr(VI) sorption capacity and kinetics using column experiments and reactive transport modeling. Our results showed that the sorbed mass and rates can differ by an order of magnitude due to of the illite spatial heterogeneities and transport limitation. With constraints from data, we also developed the capabilities of modeling Cr(VI) in heterogeneous media. The developed model is then utilized to understand the general principles that govern the relationship between sorption and connectivity, a key measure of the spatial pattern characteristics. This correlation can be used to estimate Cr(VI) sorption characteristics in heterogeneous porous media. Insights gained here bridge gaps between laboratory and field application in hydrogeology and geochemical field, and advance predictive understanding of reactive transport processes in the natural heterogeneous subsurface. We believe that these findings will be of interest to a large number of environmental geochemists and engineers, hydrogeologists, and those interested in contaminant fate and transport, water quality and water composition, and natural attenuation processes in natural systems.

  15. Audit Report: CR-B-97-04 | Department of Energy

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

    5, 1997 Audit OF Controls Over The ADP Support Services Contract The Federal Acquisition Regulation requires the Department of Energy (Department) to ensure that efficient methods and effective cost controls are used over its cost-reimbursement contracts. Our objective was to determine whether the program offices at the Department's Headquarters were managing their Automated Data Processing (ADP) support services contract costs. PDF icon Audit Report: CR-B-97-04 More Documents & Publications

  16. Audit Report: CR-B-98-02 | Department of Energy

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

    2 Audit Report: CR-B-98-02 November 14, 1997 Audit of Management of the Laboratory Directed Research and Development Program at the Lawrence Livermore National Laboratory The Department's national laboratories, since their establishment, have been permitted to conduct a limited amount of discretionary research activities. The Department's Defense Program laboratories, such as the Lawrence Livermore National Laboratory, generate funding for Laboratory Directed Research and Development (LDRD)

  17. Audit Report: CR-B-99-01 | Department of Energy

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

    1 Audit Report: CR-B-99-01 October 1, 1998 Department's Working Capital Fund The Department established the Working Capital Fund (Fund) in January 1996 as a financial management tool for charging the costs of common services provided at Headquarters to Departmental program offices. The objectives in establishing the Fund were to increase efficiency of the Department's operations, improve management of administrative services through the use of flexible and business-like finance methods, and

  18. Audit Report: CR-FS-99-01 | Department of Energy

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

    9-01 Audit Report: CR-FS-99-01 June 15, 1999 Management Report Audit of the Department of Energy's Consolidated Financial Statements for Fiscal Year 1998 As required by the Government Management Reform Act of 1994, we audited the U.S. Department of Energy's (Department) consolidated financial statements as of and for the years ended September 30, 1998 and 1997 to determine whether they presented fairly, in all material respects, the Department's financial position, net cost, changes in net

  19. Audit Report: CR-L-01-06 | Department of Energy

    Energy Savers [EERE]

    L-01-06 Audit Report: CR-L-01-06 February 8, 2001 Federal Managers' Financial Integrity Act Audit Report We reviewed the Department of Energy's (Department) progress in implementing the Federal Managers' Financial Integrity Act (FMFIA) of 1982. The review was made to assist you in determining whether the evaluations of the systems of management, accounting, and administrative controls were carried out in a reasonable and prudent manner by the Department for Fiscal Year 2000. PDF icon Audit

  20. The MSFR as a flexible CR reactor: the viewpoint of safety

    SciTech Connect (OSTI)

    Fiorina, C.; Cammi, A.; Franceschini, F.; Krepel, J.

    2013-07-01

    In this paper, the possibility has first been discussed of using the liquid-fuelled Molten Salt Fast Reactor (MSFR) as a flexible conversion ratio (CR) reactor without design modification. By tuning the reprocessing rate it is possible to determine the content of fission products in the core, which in turn can significantly affect the neutron economy without incurring in solubility problems. The MSFR can thus be operated as U-233 breeder (CR>1), iso-breeder (CR=1) and burner reactor (CR<1). In particular a 40 year doubling time can be achieved, as well as a considerable Transuranics and MA (minor actinide) burning rate equal to about 150 kg{sub HN}/GWE-yr. The safety parameters of the MSFR have then been evaluated for different fuel cycle strategies. Th use and a softer spectrum combine to give a strong Doppler coefficient, one order of magnitude higher compared to traditional fast reactors (FRs). The fuel expansion coefficient is comparable to the Doppler coefficient and is only mildly affected by core compositions, thus assisting the fuel cycle flexibility of the MSFR. ?eff and generation time are comparable to the case of traditional FRs, if a static fuel is assumed. A notable reduction of ?eff is caused by salt circulation, but a low value of this parameter is a limited concern in the MSFR thanks to the lack of a burnup reactivity swing and of positive feedbacks. A simple approach has also been developed to evaluate the MSFR capabilities to withstand all typical double-fault accidents, for different fuel cycle options.

  1. First-principles study of the structural and elastic properties of Cr{sub 2}AlX (X=N, C) compounds

    SciTech Connect (OSTI)

    Cui Shouxin; Wei Dongqing; Hu Haiquan; Feng Wenxia; Gong Zizheng

    2012-07-15

    The structural, electronic and elastic properties of Cr{sub 2}AlX, with X=N, C, have been investigated at the density functional theory level by applying a plane-wave pseudopotential approach. The band structure and density of states reveal the metallic features of Cr{sub 2}AlX. The total and projected density of states indicate that the bonding is achieved through a hybridization of Cr 3d states with Al and X-atom p states. The Cr 3d-X2p bonds are lower in energy and are stiffer than Cr 3d-Al 3p bonds. The charge density distributions indicate that there exist soft Cr-Al and relatively strong Cr-X covalent bonds, which might be responsible for their hardness. The elastic constants were obtained in the pressure range 0-100 GPa, and satisfy the stability conditions for hexagonal crystal, which indicates that these two compounds are stable in the pressure regime studied. By analyzing bulk modulus to shear modulus ratio and Cauchy pressure, Cr{sub 2}AlC is predicted to be brittleness and Cr{sub 2}AlN is ductile. The Debye temperature was obtained from the average sound velocity. - Graphical abstract: The heterogeneity of chemical bonds in Cr{sub 2}AlX (X=N, C) is observed: soft Cr-Al and relatively strong Cr-X covalent bonds might be contributed to their hardness. Highlights: Black-Right-Pointing-Pointer Cr 3d-X2p (X=N, C) bonds are lower in energy and stiffer than Cr 3d-Al 3p bonds for Cr{sub 2}AlX. Black-Right-Pointing-Pointer The hardness of Cr{sub 2}AlX might be ascribed to soft Cr-Al and relatively strong Cr-X covalent bonds. Black-Right-Pointing-Pointer The predicted brittleness of Cr{sub 2}AlC and ductility of Cr{sub 2}AlN originated from their novel structure.

  2. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    SciTech Connect (OSTI)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  3. Ferromagnetic ordering of Cr and Fe doped p-type diamond: An ab initio study

    SciTech Connect (OSTI)

    Benecha, E. M.; Lombardi, E. B.

    2014-02-21

    Ferromagnetic ordering of transition metal dopants in semiconductors holds the prospect of combining the capabilities of semiconductors and magnetic systems in single hybrid devices for spintronic applications. Various semiconductors have so far been considered for spintronic applications, but low Curie temperatures have hindered room temperature applications. We report ab initio DFT calculations on the stability and magnetic properties of Fe and Cr impurities in diamond, and show that their ground state magnetic ordering and stabilization energies depend strongly on the charge state and type of co-doping. We predict that divacancy Cr{sup +2} and substitutional Fe{sup +1} order ferromagnetically in p-type diamond, with magnetic stabilization energies (and magnetic moment per impurity ion) of 16.9 meV (2.5 μ{sub B}) and 33.3 meV (1.0 μ{sub B}), respectively. These magnetic stabilization energies are much larger than what has been achieved in other semiconductors at comparable impurity concentrations, including the archetypal dilute magnetic semiconductor GaAs:Mn. In addition, substitutional Fe{sup +1} exhibits a strong half-metallic character, with the Fermi level crossing bands in only the spin down channel. These results, combined with diamond’s extreme properties, demonstrate that Cr or Fe dopedp-type diamond may successfully be considered in the search for room temperature spintronic materials.

  4. Cr-doped TiSe2 - A layered dichalcogenide spin glass

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

    Luo, Huixia; Tao, Jing; Krizan, Jason W.; Seibel, Elizabeth M.; Xie, Weiwei; Sahasrabudhe, Girija S.; Bergman, Susanna L.; Phelan, Brendan F.; Wang, Zhen; Zhang, Jiandi; et al

    2015-09-17

    We report the magnetic characterization of the Cr-doped layered dichalcogenide TiSe2. The temperature dependent magnetic susceptibilities are typical of those seen in geometrically frustrated insulating antiferromagnets. The Cr moment is close to the spin-only value, and the Curie–Weiss temperatures (θcw) are between –90 and –230 K. Freezing of the spin system, which is glassy, characterized by peaks in the ac and dc susceptibility and specific heat, does not occur until below T/θcw = 0.05. The CDW transition seen in the resistivity for pure TiSe2 is still present for 3% Cr substitution but is absent by 10% substitution, above which themore » materials are metallic and p-type. Structural refinements, magnetic characterization, and chemical considerations indicate that the materials are of the type Ti1–xCrxSe2-x/2 for 0 ≤ x ≤ 0.6.« less

  5. Sintered Cr/Pt and Ni/Au ohmic contacts to B12P2

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

    Frye, Clint D.; Kucheyev, Sergei O.; Edgar, James H.; Voss, Lars F.; Conway, Adam M.; Shao, Qinghui; Nikolic, Rebecca J.

    2015-04-09

    With this study, icosahedral boron phosphide (B12P2) is a wide-bandgap semiconductor possessing interesting properties such as high hardness, chemical inertness, and the reported ability to self-heal from irradiation by high energy electrons. Here, the authors developed Cr/Pt and Ni/Au ohmic contacts to epitaxially grown B12P2 for materials characterization and electronic device development. Cr/Pt contacts became ohmic after annealing at 700 °C for 30 s with a specific contact resistance of 2×10–4 Ω cm2, as measured by the linear transfer length method. Ni/Au contacts were ohmic prior to any annealing, and their minimum specific contact resistance was ~l–4 × 10–4 Ωmore » cm2 after annealing over the temperature range of 500–800 °C. Rutherford backscattering spectrometry revealed a strong reaction and intermixing between Cr/Pt and B12P2 at 700 °C and a reaction layer between Ni and B12P2 thinner than ~25 nm at 500 °C.« less

  6. Blending Cr2O3 into a NiO-Ni electrocatalyst for sustained water splitting

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

    Gong, Ming; Zhou, Wu; Kenney, Michael James; Kapusta, Rich; Cowley, Sam; Wu, Yingpeng; Lu, Bingan; Lin, Meng -Chang; Wang, Di -Yan; Yang, Jiang; et al

    2015-08-24

    The rising H2 economy demands active and durable electrocatalysts based on low-cost, earth-abundant materials for water electrolysis/photolysis. Here we report nanoscale Ni metal cores over-coated by a Cr2O3-blended NiO layer synthesized on metallic foam substrates. The Ni@NiO/Cr2O3 triphase material exhibits superior activity and stability similar to Pt for the hydrogen-evolution reaction in basic solutions. The chemically stable Cr2O3 is crucial for preventing oxidation of the Ni core, maintaining abundant NiO/Ni interfaces as catalytically active sites in the heterostructure and thus imparting high stability to the hydrogen-evolution catalyst. The highly active and stable electrocatalyst enables an alkaline electrolyzer operating at 20more » mA cm–2 at a voltage lower than 1.5 V, lasting longer than 3 weeks without decay. Thus, the non-precious metal catalysts afford a high efficiency of about 15 % for light-driven water splitting using GaAs solar cells.« less

  7. Rapid preparation and magnetodielectric properties of trirutile Cr{sub 2}WO{sub 6}

    SciTech Connect (OSTI)

    Gaultois, Michael W.; Kemei, Moureen C.; Harada, Jaye K.; Seshadri, Ram

    2015-01-07

    Dense pellets of > 99% purity trirutile Cr{sub 2}WO{sub 6} were prepared in one step from starting oxides using spark plasma sintering, leading to simultaneous reaction and consolidation in 3 min at 1473 K. The reducing environment during processing may be partly responsible for the rapid reaction time in these oxides, with partial reduction of Cr{sup 3+} and the associated oxygen vacancies allowing rapid diffusion of cations. The low-temperature physical properties of Cr{sub 2}WO{sub 6} were examined, and a new transition at T = 5.9 K was observed as an anomaly in the temperature-dependent dielectric permittivity and a corresponding anomaly in the specific heat. A strong enhancement of the magnetocapacitance is observed below this transition temperature at T = 5.9 K and may be associated with a change from collinear spin order to more complex spin order.

  8. Method for generating a crystalline {sup 99}MoO{sub 3} product and the isolation {sup 99m}Tc compositions therefrom

    DOE Patents [OSTI]

    Bennett, R.G.; Christian, J.D.; Kirkham, R.J.; Tranter, T.J.

    1998-09-01

    An improved method is described for producing {sup 99m}Tc compositions. {sup 100}Mo metal is irradiated with photons in a particle (electron) accelerator to produce {sup 99}Mo metal which is dissolved in a solvent. A solvated {sup 99}Mo product is then dried to generate a supply of {sup 99}MoO{sub 3} crystals. The crystals are thereafter heated at a temperature which will sublimate the crystals and form a gaseous mixture containing vaporized {sup 99m}TcO{sub 3} and vaporized {sup 99m}TcO{sub 2} but will not cause the production of vaporized {sup 99}MoO{sub 3}. The mixture is then combined with an oxidizing gas to generate a gaseous stream containing vaporized {sup 99m}Tc{sub 2}O{sub 7}. Next, the gaseous stream is cooled to a temperature sufficient to convert the vaporized {sup 99m}Tc{sub 2}O{sub 7} into a condensed {sup 99m}Tc-containing product. The product has high purity levels resulting from the use of reduced temperature conditions and ultrafine crystalline {sup 99}MoO{sub 3} starting materials with segregated {sup 99m}Tc compositions therein which avoid the production of vaporized {sup 99}MoO{sub 3} contaminants. 1 fig.

  9. Method for generating a crystalline .sup.99 MoO.sub.3 product and the isolation .sup.99m Tc compositions therefrom

    DOE Patents [OSTI]

    Bennett, Ralph G.; Christian, Jerry D.; Kirkham, Robert J.; Tranter, Troy J.

    1998-01-01

    An improved method for producing .sup.99m Tc compositions. .sup.100 Mo metal is irradiated with photons in a particle (electron) accelerator to produce .sup.99 Mo metal which is dissolved in a solvent. A solvated .sup.99 Mo product is then dried to generate a supply of .sup.99 MoO.sub.3 crystals. The crystals are thereafter heated at a temperature which will sublimate the crystals and form a gaseous mixture containing vaporized .sup.99m TcO.sub.3 and vaporized .sup.99m TcO.sub.2 but will not cause the production of vaporized .sup.99 MoO.sub.3. The mixture is then combined with an oxidizing gas to generate a gaseous stream containing vaporized .sup.99m Tc.sub.2 O.sub.7. Next, the gaseous stream is cooled to a temperature sufficient to convert the vaporized .sup.99m Tc.sub.2 O.sub.7 into a condensed .sup.99m Tc-containing product. The product has high purity levels resulting from the use of reduced temperature conditions and ultrafine crystalline .sup.99 MoO.sub.3 starting materials with segregated .sup.99m Tc compositions therein which avoid the production of vaporized .sup.99 MoO.sub.3 contaminants.

  10. Facile deposition of Ag{sub 3}PO{sub 4} on graphene-like MoS{sub 2} nanosheets for highly efficient photocatalysis

    SciTech Connect (OSTI)

    Wang, Peifu; Shi, Penghui; Hong, Yuanchen; Zhou, Xuejun; Yao, Weifeng

    2015-02-15

    Graphical abstract: The photocatalytic performance of Ag{sub 3}PO{sub 4} was highly improved by the in situ deposition of Ag{sub 3}PO{sub 4} particles on graphene-like MoS{sub 2} nanosheets. - Highlights: A novel composite photocatalyst was synthesized by depositing Ag{sub 3}PO{sub 4} on the graphene-like MoS{sub 2} nanosheets. Ag{sub 3}PO{sub 4}/MoS{sub 2} photocatalyst exhibited a high photocatalytic activity for RhB degradation. Graphene-like MoS{sub 2} nanosheets. MoS{sub 2} nanosheets play an important role in photocatalytic activity by serving as an effective acceptor of the photogenerated carriers. - Abstract: A facile method for the in situ deposition of Ag{sub 3}PO{sub 4} on graphene-like MoS{sub 2} nanosheets was developed to improve the photocatalytic performance of Ag{sub 3}PO{sub 4} catalysts. The heterostructure of Ag{sub 3}PO{sub 4}/MoS{sub 2} composites was characterized by using X-ray diffraction spectra (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The prepared Ag{sub 3}PO{sub 4}/MoS{sub 2} photocatalyst exhibited a much higher photocatalytic activity than that of Ag{sub 3}PO{sub 4} for the degradation of Rhodamine B (RhB) under visible light irradiation (>400 nm). The improved photocatalytic activity of Ag{sub 3}PO{sub 4}/MoS{sub 2} is attributed to the efficient separation of photogenerated electronhole pairs in the composite. This result provides a new perspective on the design of high-performance photocatalysts which is promising for energy applications.

  11. Effect of lattice deformation on exchange coupling constants in Cr{sub 2}O{sub 3}

    SciTech Connect (OSTI)

    Kota, Yohei; Imamura, Hiroshi; Sasaki, Munetaka

    2014-05-07

    We studied lattice deformation effect on exchange interaction in the corundum-type Cr{sub 2}O{sub 3} theoretically. First-principles electronic structure calculations were performed to evaluate the total energy and exchange coupling constants of Cr{sub 2}O{sub 3} under lattice deformation. We found that a few percent elastic deformation is expected via misfit strain and that the first- and second-nearest neighbor exchange coupling constants of Cr{sub 2}O{sub 3} strongly depend on the lattice deformation. These results imply a possibility for improving the thermal stability of Cr{sub 2}O{sub 3} based magnetoelectric devices by lattice deformation.

  12. LaCrO{sub 3} heteroepitaxy on SrTiO{sub 3}(001) by molecular beam epitaxy

    SciTech Connect (OSTI)

    Qiao, L.; Droubay, T. C.; Bowden, M. E.; Shutthanandan, V.; Kaspar, T. C.; Chambers, S. A.

    2011-08-08

    Stoichiometric, epitaxial LaCrO{sub 3} films have been grown on SrTiO{sub 3}(001) by molecular beam epitaxy using O{sub 2} as the oxidant. Films grew in a layer-by-layer fashion, giving rise to coherently strained, structurally excellent films and surfaces which preserve the step-terrace structure of the substrate. The critical thickness is in excess of 500 A. Cr(III) near the surface is easily oxidized to Cr(V) upon exposure to atomic oxygen and reduction back to Cr(III) is readily achieved by vacuum annealing, resulting in tunability of the charge state at the B-site cation.

  13. LaCrO3 heteroepitaxy on SrTiO3(001) by molecular beam epitaxy

    SciTech Connect (OSTI)

    Qiao, Liang; Droubay, Timothy C.; Bowden, Mark E.; Shutthanandan, V.; Kaspar, Tiffany C.; Chambers, Scott A.

    2011-08-09

    Stoichiometric, epitaxial LaCrO3 films have been grown on TiO2-terminated SrTiO3(001) substrates by molecular beam epitaxy using O2 as the oxidant. Film growth occurred in a layer-by-layer fashion, giving rise to structurally excellent films and surfaces which preserve the step-terrace structure of the substrate. The critical thickness is in excess of 500 . Near-surface Cr(III) is highly susceptible to further oxidation to Cr(V), leading to the formation of a disordered phase upon exposure to atomic oxygen. Recovery of the original epitaxial LaCrO3 phase is readily achieved by vacuum annealing.

  14. Strain induced ferromagnetism in epitaxial Cr{sub 2}O{sub 3} thin films integrated on Si(001)

    SciTech Connect (OSTI)

    Punugupati, Sandhyarani Narayan, Jagdish; Hunte, Frank

    2014-09-29

    We report on the epitaxial growth and magnetic properties of antiferromagnetic and magnetoelectric (ME) Cr{sub 2}O{sub 3} thin films deposited on cubic yttria stabilized zirconia (c-YSZ)/Si(001) using pulsed laser deposition. The X-ray diffraction (2ϴ and Φ) and TEM characterizations confirm that the films were grown epitaxially. The Cr{sub 2}O{sub 3}(0001) growth on YSZ(001) occurs with twin domains. There are four domains of Cr{sub 2}O{sub 3} with in-plane rotation of 30° or 150° from each other about the [0001] growth direction. The epitaxial relation between the layers is given as [001]Si ‖ [001]YSZ ‖ [0001]Cr{sub 2}O{sub 3} and [100]Si ǁ [100]YSZ ǁ [101{sup ¯}0] Cr{sub 2}O{sub 3} or [112{sup ¯}0] Cr{sub 2}O{sub 3}. Though the bulk Cr{sub 2}O{sub 3} is an antiferromagnetic with T{sub N} = 307 K, we found that the films exhibit ferromagnetic like hysteresis loops with high saturation and finite coercive field up to 400 K. The thickness dependent magnetizations together with oxygen annealing results suggest that the ferromagnetism (FM) is due to oxygen related defects whose concentration is controlled by strain present in the films. This FM, in addition to the intrinsic magneto-electric properties of Cr{sub 2}O{sub 3}, opens the door to relevant spintronics applications.

  15. Cr-W-V bainitic/ferritic steel with improved strength and toughness and method of making

    DOE Patents [OSTI]

    Klueh, Ronald L.; Maziasz, Philip J.

    1994-01-01

    A high strength, high toughness Cr-W-V ferritic steel composition suitable for fast induced-radioactivity (FIRD) decay after irradiation in a fusion reactor comprises 2.5-3.5 wt % Cr, 2. This invention was made with Government support under contract DE-AC05-840R21400 awarded by the U.S. Department of Energy to Martin Marietta Energy Systems, Inc. and the Government has certain rights in this invention.

  16. Results of U-xMo (x=7, 10, 12 wt.%) Alloy versus Al-6061 Cladding Diffusion Couple Experiments Performed at 500, 550 and 600 Degrees C

    SciTech Connect (OSTI)

    Emmanuel Perez; Dennis D. Keiser, Jr.; Yongho Sohn

    2013-04-01

    The Reduced Enrichment for Research and Test Reactors (RERTR) program has been developing low enrichment fuel systems encased in Al 6061 for use in research and test reactors. U–Mo alloys in contact with Al and Al alloys can undergo diffusional interactions that can result in the development of interdiffusion zones with complex fine-grained microstructures composed of multiple phases. A monolithic fuel currently being developed by the RERTR program has local regions where the U–Mo fuel plate is in contact with the Al 6061 cladding and, as a result, the program finds information about interdiffusion zone development at high temperatures of interest. In this study, the microstructural development of diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo, and U-12wt.%Mo vs. Al 6061 (or 6061 aluminum) cladding, annealed at 500, 550, 600 degrees C for 1, 5, 20, 24, or 132 hours, was analyzed by backscatter electron microscopy and x-ray energy dispersive spectroscopy on a scanning electron microscope. Concentration profiles were determined by standardized wavelength dispersive spectroscopy and standardless x-ray energy dispersive spectroscopy. The results of this work shows that the presence of surface layers at the U–Mo/Al 6061 interface can dramatically impact the overall interdiffusion behavior in terms of rate of interaction and uniformity of the developed interdiffusion zones. It further reveals that relatively uniform interaction layers with higher Si concentrations can develop in U–Mo/Al 6061 couples annealed at shorter times and that longer times at temperature result in the development of more non-uniform interaction layers with more areas that are enriched in Al. At longer annealing times and relatively high temperatures, U–Mo/Al 6061 couples can exhibit more interaction compared to U–Mo/pure Al couples. The minor alloying constituents in Al 6061 cladding can result in the development of many complex phases in the interaction layer of U–Mo/Al–6061 cladding couples, and some phases in the interdiffusion zones of U–Mo/Al–6061 cladding couples are likely similar to those observed for U–Mo/pure Al couples.

  17. CR108, a novel vitamin K3 derivative induces apoptosis and breast tumor inhibition by reactive oxygen species and mitochondrial dysfunction

    SciTech Connect (OSTI)

    Yang, Chun-Ru; Liao, Wei-Siang; Wu, Ya-Hui; Murugan, Kaliyappan; Chen, Chinpiao; Chao, Jui-I

    2013-12-15

    Vitamin K3 derivatives have been shown to exert anticancer activities. Here we show a novel vitamin K3 derivative (S)-2-(2-hydroxy-3-methylbutylthio)naphthalene-1,4-dione, which is named as CR108 that induces apoptosis and tumor inhibition through reactive oxygen species (ROS) and mitochondrial dysfunction in human breast cancer. CR108 is more effective on the breast cancer cell death than other vitamin K3 derivatives. Moreover, CR108 induced apoptosis in both the non-HER-2-overexpressed MCF-7 and HER-2-overexpressed BT-474 breast cancer cells. CR108 caused the loss of mitochondrial membrane potential, cytochrome c released from mitochondria to cytosol, and cleaved PARP proteins for apoptosis induction. CR108 markedly increased ROS levels in breast cancer cells. N-acetylcysteine (NAC), a general ROS scavenger, completely blocked the CR108-induced ROS levels, mitochondrial dysfunction and apoptosis. Interestingly, CR108 increased the phosphorylation of p38 MAP kinase but conversely inhibited the survivin protein expression. NAC treatment prevented the activation of p38 MAP kinase and rescued the survivin protein levels. SB202190, a specific p38 MAP kinase inhibitor, recovered the survivin protein levels and attenuated the cytotoxicity of CR108-treated cells. Furthermore, CR108 inhibited the xenografted human breast tumor growth in nude mice. Together, we demonstrate that CR108 is a novel vitamin K3 derivative that induces apoptosis and tumor inhibition by ROS production and mitochondrial dysfunction and associates with the phosphorylation of p38 MAP kinase and the inhibition of survivin in the human breast cancer. - Highlights: CR108 is more effective on the cell death than other vitamin K3 derivatives. CR108 induces apoptosis and tumor inhibition by ROS and mitochondrial dysfunction. CR108 induces apoptosis by p38 kinase activation and survivin inhibition. CR108 is a potent vitamin K3 analog that can develop for breast cancer therapy.

  18. Cobalt-doped Bi{sub 26}Mo{sub 10}O{sub 69}: Crystal structure and conductivity

    SciTech Connect (OSTI)

    Mikhailovskaya, Z.A.; Buyanova, E.S.; Petrova, S.A.; Morozova, M.V.; Zhukovskiy, V.M.; Zakharov, R.G.; Tarakina, N.V.; Berger, I.F.

    2013-08-15

    A series of cobalt-doped bismuth molybdates were synthesized and investigated using X-ray powder diffraction, transmission electron microscopy and impedance spectroscopy. The ranges of solid solution were determined. Two new compounds, Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} (x=0.2) and Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} (y=0.2), which crystallise in monoclinic unit cells have been examined in detail by diffraction methods. Impedance spectroscopy measurements show that the studied materials are good ionic conductors with conductivity values about 510{sup ?3} Scm{sup ?1} at 973 K and 1.710{sup ?4} Scm{sup ?1} at 623 K, which are similar to conductivity values of yttrium substituted zirconia and (YSZ) gadolinium doped ceria (CGO). - Graphical abstract: Measured and calculated diffraction spectra for Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} and projection of the Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} crystal structure onto the ac plane. Highlights: The limit of the Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} homogeneity range is equal to x=0.2. The limit of the Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} homogeneity range is equal to y=0.2. Solid solutions have monoclinic symmetry. No phase transition is observed. The conductivity at 700 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=2.23. The conductivity at 350 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=3.74.

  19. Characterization of Cr poisoning in a solid oxide fuel cell cathode using a high-energy x-ray microbeam.

    SciTech Connect (OSTI)

    Liu, D. J.; Almer, J.; Cruse, T.

    2010-01-01

    A key feature of planar solid oxide fuel cells (SOFCs) is the feasibility of using metallic interconnects made of high temperature ferritic stainless steels, which reduce system cost while providing excellent electric conductivity. Such interconnects, however, contain high levels of chromium, which has been found to be associated with SOFC cathode performance degradation at SOFC operating temperatures; a phenomenon known as Cr poisoning. Here, we demonstrate an accurate measurement of the phase and concentration distributions of Cr species in a degraded SOFC, as well as related properties including deviatoric strain, integrated porosity, and lattice parameter variation, using high energy microbeam X-ray diffraction and radiography. We unambiguously identify (MnCr){sub 3}O{sub 4} and Cr{sub 2}O{sub 3} as the two main contaminant phases and find that their concentrations correlate strongly with the cathode layer composition. Cr{sub 2}O{sub 3} deposition within the active cathode region reduces porosity and produces compressive residual strains, which hinders the reactant gas percolation and can cause structural breakdown of the SOFC cathode. The information obtained through this study can be used to better understand the Cr-poisoning mechanism and improve SOFC design.

  20. Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional ferromagnetic material

    SciTech Connect (OSTI)

    Lin, Ming -Wei; Zhung, Houlong L.; Yan, Jiaqiang; Ward, Thomas Zac; Puretzky, Alexander A.; Rouleau, Christopher M.; Gai, Zheng; Liang, Liangbo; Meunier, Vincent; Ganesh, Panchapakesan; Kent, Paul R. C.; Sumpter, Bobby G.; Mandrus, David G.; Geohegan, David B.; Xiao, Kai

    2015-11-27

    Finite range ferromagnetism and antiferromagnetism in two-dimensional (2D) systems within an isotropic Heisenberg model at non-zero temperature were originally proposed to be impossible. However, recent theoretical studies using an Ising model have recently shown that 2D magnetic crystals can exhibit magnetism. Experimental verification of existing 2D magnetic crystals in this system has remained elusive. In this work we for the first time exfoliate the CrSiTe3, a bulk ferromagnetic semiconductor, to mono- and few-layer 2D crystals onto a Si/SiO2 substrate. The Raman spectra show the good stability and high quality of the exfoliated flakes, consistent with the computed phonon spectra of 2D CrSiTe3, giving a strong evidence for the existence of 2D CrSiTe3 crystals. When the thickness of the CrSiTe3 crystals is reduced to few-layers, we observed a clear change in resistivity at 80~120 K, consistent with the theoretical calculations on the Curie temperature (Tc) of ~80 K for the magnetic ordering of 2D CrSiTe3 crystals. As a result, the ferromagnetic mono- and few-layer 2D CrSiTe3 indicated here should enable numerous applications in nano-spintronics.

  1. Hole-induced insulator-to-metal transition in La1-xSrxCrO3 epitaxial films

    SciTech Connect (OSTI)

    Zhang, Hongliang; Du, Yingge; Sushko, Petr; Bowden, Mark E.; Shutthanandan, V.; Sallis, Shawn; Piper, Louis F. J.; Chambers, Scott A.

    2015-04-01

    We have investigated the evolution of the structural and electronic properties of La1-xSrxCrO3 (0 ? x ? 1) epitaxial films deposited by molecular beam epitaxy (MBE) using x-ray diffraction, x-ray photoemission spectroscopy, x-ray absorption spectroscopy, electrical transport, and ab initio modeling. LaCrO3 is an antiferromagnetic Mott insulator whereas stoichiometric SrCrO3 is a metal. Substituting Sr2+ for La3+ in LaCrO3 effectively dopes holes into the top of valence band, leading to Cr4+ (3d2) local electron configurations. Core-level and valence-band features monotonically shift to lower binding energy with increasing x, indicating downward movement of the Fermi level toward the valence band maximum. An insulator-to-metal like transition is observed at x ? 0. 65 even as the material becomes a p-type semiconductor at lower doping level and eventually becomes degenerately doped. Valence band x-ray photoemission spectroscopy reveals diminution of electronic state density at the top of the valence band while O K-edge x-ray absorption spectroscopy shows the development of a new unoccupied state above the Fermi level as holes are doped into LaCrO3. These results indicate a pronounced redistribution of electronic state density of states upon hole doping, a result that is also obtained by density functional theory with a Hubbard U correction.

  2. Development of an Immobilisation Technology for Radioactive Waste Solution from Mo-99 Production

    SciTech Connect (OSTI)

    Sizgek, G.D.; Sizgek, E.

    2006-07-01

    Australian Nuclear Science and Technology Organisation (ANSTO) developed a method to immobilize the Intermediate Level Liquid Waste (ILLW) arising from its Mo-99 production process. The immobilisation process involves impregnation of waste solution into ceramic precursor powders, drying, calcining and consolidation (Hot Isostatic Pressing, HIP) to produce final ceramic waste form. Ceramic precursor powder is produced by spray drying of a sol-gel based colloidal dispersion. These free-flowing, microspherical, 20-80 microns, precursors have porosity of 40-50%. An in-house custom designed and manufactured microwave-heated and mechanically fluidized mixer-drier was used for impregnation of the precursor powder with the simulated waste (Depleted Uranyl Nitrate Hexahydrate, DUNH, and inactive Cs, Sr nitrates as fission products) and drying. During impregnation an evaporation rate of 1 l/h water per kW microwave energy in steady state was achieved by matching the feed rate of DUNH to produce equivalent of 35% UO{sub 2} loading. It was demonstrated that the tuned microwave energy can be delivered to the mixer-drier during the entire impregnation process within very low reflection values. The samples of the waste loaded free-flowing powder were subsequently calcined at 750 deg. C under reducing atmosphere for thermal denitration and mineral phase nucleation. Calcined powders were filled into cans. After evacuation and sealing, the cans were isostatically pressed at 1260 deg. C. The consolidated ceramic waste form produced from the DUNH run has been assessed by durability and material characterization tests. Successful confirmation of each processing step at pilot and/or plant scale, has led to the design and construction of the overall process at full scale (equivalent of processing 8 kg U per batch) in a simulated hot-cell mock-up plant. The constructed plant mainly consists of a Microwave-heated Mechanical Fluidized Bed (MWMFB) mixer-drier a fluidized bed calciner, an off gas unit, material transfer/holding and can filling units. Performance of the overall process by integrating each of the processing steps and material transfer operations are currently being tested with inactive simulants from the point of remote operated plant design perspective. Definitive design of a hot-cell production system has been initiated in parallel to the mock-up plant tests. This paper describes the results of both full-scale DUNH impregnation run and inactive mock-up plant tests in developing unique Mo-99 waste immobilisation technology. (authors)

  3. Calculation of Design Parameters for an Equilibrium LEU Core in the NBSR using a U7Mo Dispersion Fuel

    SciTech Connect (OSTI)

    Hanson A. L.; Diamond D.

    2014-06-30

    A plan is being developed for the conversion of the NIST research reactor (NBSR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. The LEU fuel may be a monolithic foil (LEUm) of U10Mo (10% molybdenum by weight in an alloy with uranium) or a dispersion of U7Mo in aluminum (LEUd). A previous report provided neutronic calculations for the LEUm fuel and this report presents the neutronics parameters for the LEUd fuel. The neutronics parameters for the LEUd fuel are compared to those previously obtained for the present HEU fuel and the proposed LEUm fuel. The results show no significant differences between the LEUm and the LEUd other than the LEUd fuel requires slightly less uranium than the LEUm fuel due to less molybdenum being present. The calculations include kinetics parameters, reactivity coefficients, reactivity worths of control elements and abnormal configurations, and power distributions under normal operation and with misloaded fuel elements.

  4. 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.

  5. Update to M&O Contractor Model Subcontract entitled "Standard Research Subcontract (Educational Institution or Nonprofit Organization)"

    Broader source: Energy.gov [DOE]

    The purpose of this Policy Flash is to disseminate an update to the Management and Operating (M&O) Contractor Standard Research Subcontract (Educational Institution or Nonprofit Organization) Model. The original Model was championed by the Integrated Contractor Purchasing Team and included representatives from other federally funded research facilities and DOE/NNSA. The attached update represents a similar stakeholder's collaboration. DOE/NNSA encourages M&O contractors to use this model subcontractor for unclassified research and development work not related to nuclear, chemical, biological, or radiological weapons of mass destruction or the production of special nuclear material. If the proposed subcontract is for other than standard research and development work (e.g., work performed on a DOE/NNSA site, a programmatic requirement for open source software distribution, etc.), the articles and clauses in the model should be tailored to address those specific requirements.

  6. Mass Measurements of Very Neutron-Deficient Mo and Tc Isotopes and Their Impact on rp Process Nucleosynthesis

    SciTech Connect (OSTI)

    Haettner, E.; Plass, W. R.; Scheidenberger, C.; Ackermann, D.; Block, M.; Eliseev, S.; Herfurth, F.; Hessberger, F. P.; Hofmann, S.; Kluge, H.-J.; Audi, G.; Blaum, K.; Ketter, J.; Fleckenstein, T.; Ketelaer, J.; Marx, G.; Schweikhard, L.; Mazzocco, M.; Novikov, Yu. N.; Vorobjev, G.

    2011-03-25

    The masses of ten proton-rich nuclides, including the N=Z+1 nuclides {sup 85}Mo and {sup 87}Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical x-ray bursts. Surprisingly low {alpha} separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.

  7. Separation of interlayer resistance in multilayer MoS{sub 2} field-effect transistors

    SciTech Connect (OSTI)

    Na, Junhong; Jeong Kim, Yun; Kim, Gyu-Tae; Shin, Minju; Joo, Min-Kyu; Huh, Junghwan; Jong Choi, Hyung; Hyung Shim, Joon

    2014-06-09

    We extracted the interlayer resistance between two layers in multilayer molybdenum disulfide (MoS{sub 2}) field-effect transistors by confirming that contact resistances (R{sub contact}) measured using the four-probe measurements were similar, within ∼30%, to source/drain series resistances (R{sub sd}) measured using the two-probe measurements. R{sub contact} values obtained from gated four-probe measurements exhibited gate voltage dependency. In the two-probe measurements, the Y-function method was applied to obtain the R{sub sd} values. By comparing those two R{sub contact} (∼9.5 kΩ) and R{sub sd} (∼12.3 kΩ) values in strong accumulation regime, we found the rationality that those two values had nearly the same properties, i.e., the Schottky barrier resistances and interlayer resistances. The R{sub sd} values of devices with two-probe source/drain electrodes exhibited thickness dependency due to interlayer resistance changes. The interlayer resistance between two layers was also obtained as ∼2.0 Ω mm.

  8. Measurement of fission gas release from irradiated UMo monolithic fuel samples

    SciTech Connect (OSTI)

    Burkes, Douglas E.; Casella, Amanda J.; Casella, Andrew M.; Luscher, Walter G.; Rice, Francine J.; Pool, Karl N.

    2015-06-01

    The uraniummolybdenum (U-Mo) alloy in a monolithic form has been proposed as one fuel design capable of converting some of the worlds highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An apparatus capable of heating post-irradiated small-scale samples cut from larger fuel segments according to specified thermal profiles under a controlled atmosphere has been installed into a hot cell. Results show that optimized experimental parameters to investigate fission product release from small samples have been established. Initial measurements conducted on aluminum alloy clad uraniummolybdenum monolithic fuel samples reveal three clear fission gas release events over the temperature range of 30-1000 C. The mechanisms responsible for these events are discussed, and the results have been compared with available information in the literature.

  9. Modeling the Influence of Interaction Layer Formation on Thermal Conductivity of UMo Dispersion Fuel

    SciTech Connect (OSTI)

    Burkes, Douglas; Casella, Andrew M.; Huber, Tanja K.

    2015-01-01

    The Global Threat Reduction Initiative Program continues to develop existing and new plate- and rod-type research and test reactor fuels with maximum attainable uranium loadings capable of potentially converting a number of the worlds remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of an even higher density fuel type consisting of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel plate and can be influenced by interaction layer formation between the fuel and matrix, porosity that forms during fabrication of the fuel plates, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation and conductivity, fuel particle size, and volume fraction of fuel dispersed in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be important in determining the overall conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the fuel particle distribution by minimizing interaction layer formation and preserving the higher thermal conductivity matrix.

  10. Measurement of Fission Gas Release from Irradiated U-Mo Monolithic Fuel Samples

    SciTech Connect (OSTI)

    Burkes, Douglas; Casella, Amanda J.; Casella, Andrew M.; Luscher, Walter G.; Rice, Francine; Pool, Karl N.

    2015-06-01

    The uranium-molybdenum (U-Mo) alloy in a monolithic form has been proposed as one fuel design capable of converting some of the world’s highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An apparatus capable of annealing post-irradiated small-scale samples cut from larger fuel segments according to specified thermal profiles under a controlled atmosphere has been installed into a hot cell. Results show that optimized experimental parameters to investigate fission product release from small samples have been established. Initial measurements conducted on aluminum alloy clad uranium-molybdenum monolithic fuel samples reveal three clear fission gas release events over the temperature range of 30-1050 C. The mechanisms responsible for these events are discussed, and the results have been compared with available information in literature.

  11. Coupled spin and valley physics in monolayer MoS2 and group-VI dichalcogenides

    SciTech Connect (OSTI)

    Xiao, Di; Liu, G. B.; Feng, wanxiang; Xu, Xiaodong; Yao, Wang

    2012-01-01

    We show that inversion symmetry breaking together with spin-orbit coupling leads to coupled spin and valley physics in monolayer MoS2 and group-VI dichalcogenides, making possible controls of spin and valley in these 2D materials. The spin-valley coupling at the valence band edges suppresses spin and valley relaxation, as flip of each index alone is forbidden by the 0.1 eV valley contrasting spin splitting. Valley Hall and spin Hall effects coexist in both electron-doped and hole-doped systems. Optical interband transitions have frequency-dependent polarization selection rules which allow selective photoexcitation of carriers with various combination of valley and spin indices. Photo-induced spin Hall and valley Hall effects can generate long lived spin and valley accumulations on sample boundaries. The physics discussed here provides a route towards the integration of valleytronics and spintronics in multi-valley materials with strong spin-orbit coupling and inversion symmetry breaking.

  12. 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.

  13. Search for neutrinoless double-beta decay of Mo 100 with the NEMO-3 detector

    SciTech Connect (OSTI)

    John D. Baker; A. J. Caffrey

    2014-06-01

    We report the results of a search for the neutrinoless double- decay (0? ) of Mo 100 , using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7??kgy , no evidence for the 0? signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T 1/2 (0?)>1.110 24 years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of ?m ? ?<0.30.9??eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0? decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.210] MeV is observed for an exposure of 47??kgy .

  14. Effects of the foil flatness on irradiation performance of U10Mo monolithic mini-plates

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

    Ozaltun, Hakan; Medvedev, Pavel G.; Rabin, Barry H.

    2015-09-03

    Monolithic plate-type fuels comprise of a high density, low enrichment, U10Mo fuel foil encapsulated in a cladding material. This concept generates several fabrication challenges such as flatness, centering or thickness variation. There are concerns, if these parameters have implications on overall performance. To investigate these inquiries, the effects of the foil flatness were studied. For this, a representative plate was simulated for an ideal case. The simulations were repeated for additional cases with various foil curvatures to evaluate the effects on the irradiation performance. The results revealed that the stresses and strains induced by fabrication process are not affected bymore » the flatness of the foil. Furthermore, fabrication stresses in the foil are relieved relatively fast in the reactor. The effects of the foil flatness on peak irradiation stressstrains are minimal. There is a slight increase in temperature for the case with maximum curvature. The major impact is on the displacement characteristics. Furthermore, while the case with a flat foil produces a symmetrical swelling, if the foil is curved, more swelling occurs on the thin-cladding side and the plate bows during irradiation.« less

  15. Origin State>> CA CA ID ID ID IL KY MD MO NM NM NY NY OH SC

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

    MO NM NM NY NY OH SC TN TN TN, WA, CA TN TN TN TN Total Shipments by Route Lawrence Livermore National Laboratory General Atomics Batelle Energy Alliance Idaho National Laboratory Advanced Mixed Waste Treatment Project Argonne National Laboratory Paducah Gaseous Diffusion Plant Aberdeen Proving Grounds National Security Technologies Sandia National Laboratory Los Alamos National Laboratory Brookhaven National Laboratory CH2M Hill B&W West Valley, LLC Portsmouth Gaseous Diffusion Plant

  16. The Influence of Casting Conditions on the Microstructure of As-Cast U-10Mo Alloys: Characterization of the Casting Process Baseline

    SciTech Connect (OSTI)

    Nyberg, Eric A.; Joshi, Vineet V.; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas

    2013-12-13

    Sections of eight plate castings of uranium alloyed with 10 wt% molybdenum (U-10Mo) were sent from Y-12 to the Pacific Northwest National Laboratory (PNNL) for microstructural characterization. This report summarizes the results from this study.

  17. Cs-doped Mo as surface converter for H{sup −}/D{sup −} generation in negative ion sources: First steps and proof of principle

    SciTech Connect (OSTI)

    Schiesko, L. Hopf, C.; Höschen, T.; Meisl, G.; Encke, O.; Franzen, P.; Heinemann, B.; Hopf, C.; Fantz, U.; Cartry, G.; Achkasov, K.

    2015-04-08

    In a proof-of-principle study, molybdenum samples were implanted with a very small dose of Cs in order to test the properties of the compound as a surface converter for negative hydrogen ion production. First results on the properties of Cs doped Mo compounds show a reduction of the work function and a stable H{sup −} yield up to four hours in low density hydrogen plasma. The implanted Cs atoms were stable in the Mo lattice over one year for samples stored in vacuum and not exposed to the plasma. The surface H{sup −} generation mechanisms were identified and a comparison of the negative ion yield with pure Mo showed that the Cs doped Mo sample’s yield was much larger.

  18. Effect of annealing treatment on the electrical characteristics of Pt/Cr-embedded ZnO/Pt resistance random access memory devices

    SciTech Connect (OSTI)

    Chang, Li-Chun; Kao, Hsuan-Ling; Liu, Keng-Hao

    2014-03-15

    ZnO/Cr/ZnO trilayer films sandwiched with Pt electrodes were prepared for nonvolatile resistive memory applications. The threshold voltage of a ZnO device embedded with a 3-nm Cr interlayer was approximately 50% lower than that of a ZnO monolayer device. This study investigated threshold voltage as a function of Cr thickness. Both the ZnO monolayer device and the Cr-embedded ZnO device structures exhibited resistance switching under electrical bias both before and after rapid thermal annealing (RTA) treatment, but resistive switching effects in the two cases exhibited distinct characteristics. Compared with the as-fabricated device, the memory cell after RTA demonstrated remarkable device parameter improvements, including a lower threshold voltage, a lower write current, and a higher R{sub off}/R{sub on} ratio. Both transmission electron microscope observations and Auger electron spectroscopy revealed that the Cr charge trapping layer in Cr-embedded ZnO dispersed uniformly into the storage medium after RTA, and x-ray diffraction and x-ray photoelectron spectroscopy analyses demonstrated that the Cr atoms lost electrons to become Cr{sup 3+} ions after dispersion. These results indicated that the altered status of Cr in ZnO/Cr/ZnO trilayer films during RTA treatment was responsible for the switching mechanism transition.

  19. Correlation between morphology, chemical environment, and ferromagnetism in the intrinsic-vacancy dilute magnetic semiconductor Cr-doped Ga2Se3/Si(001)

    SciTech Connect (OSTI)

    Yitamben, E.N.; Arena, D.; Lovejoy, T.C.; Pakhomov, A.B.; Heald, S.M.; Negusse, E.; Ohuchi, F.S.; Olmstead, M.A.

    2011-01-28

    Chromium-doped gallium sesquiselenide, Cr:Ga{sub 2}Se{sub 3}, is a member of a new class of dilute magnetic semiconductors exploiting intrinsic vacancies in the host material. The correlation among room-temperature ferromagnetism, surface morphology, electronic structure, chromium concentration, and local chemical and structural environments in Cr:Ga{sub 2}Se{sub 3} films grown epitaxially on silicon is investigated with magnetometry, scanning tunneling microscopy, photoemission spectroscopy, and x-ray absorption spectroscopy. Inclusion of a few percent chromium in Ga{sub 2}Se{sub 3} results in laminar, semiconducting films that are ferromagnetic at room temperature with a magnetic moment 4{micro}{sub B}/Cr. The intrinsic-vacancy structure of defected-zinc-blende {beta}-Ga{sub 2}Se{sub 3} enables Cr incorporation in a locally octahedral site without disrupting long-range order, determined by x-ray absorption spectroscopy, as well as strong overlap between Cr 3d states and the Se 4p states lining the intrinsic-vacancy rows, observed with photoemission. The highest magnetic moment per Cr is observed near the solubility limit of roughly one Cr per three vacancies. At higher Cr concentrations, islanded, metallic films result, with a magnetic moment that depends strongly on surface morphology. The effective valence is Cr{sup 3+} in laminar films, with introduction of Cr{sup 0} upon islanding. A mechanism is proposed for laminar films whereby ordered intrinsic vacancies mediate ferromagnetism.

  20. Optimal electron irradiation as a tool for functionalization of MoS{sub 2}: Theoretical and experimental investigation

    SciTech Connect (OSTI)

    Karmakar, Debjani Padma, N.; Ghosh, M.; Kaur, M.; Chandrasekhar Rao, T. V.; Halder, Rumu; Abraham, Geogy; Vaibhav, K.; Bhattacharya, D.

    2015-04-07

    We demonstrate the utility of electron irradiation as a tool to enhance device functionality of graphene-analogous MoS{sub 2}. With the help of first-principles based calculations, vacancy-induced changes of various electronic properties are shown to be a combined result of crystal-field modification and spin-orbital coupling. A comparative theoretical study of various possible vacancy configurations both in bulk and monolayer MoS{sub 2} and related changes in their respective band-structures help us to explain plausible irradiation induced effects. Experimentally, various structural forms of MoS{sub 2} in bulk, few layered flakes, and nanocrystals are observed to exhibit important modification of their magnetic, transport, and vibrational properties, following low doses of electron irradiation. While irradiated single crystals and nanocrystals show an enhanced magnetization, transport properties of few-layered devices show a significant increase in their conductivity, which can be very useful for fabrication of electronic devices. Our theoretical calculations reveal that this increase in n-type conductivity and magnetization can be correlated with the presence of sulfur and molybdenum vacancies.

  1. Reconfigurable p-n junction diodes and the photovoltaic effect in exfoliated MoS{sub 2} films

    SciTech Connect (OSTI)

    Sutar, Surajit; Agnihotri, Pratik; Comfort, Everett; Ung Lee, Ji; Taniguchi, T.; Watanabe, K.

    2014-03-24

    Realizing basic semiconductor devices such as p-n junctions are necessary for developing thin-film and optoelectronic technologies in emerging planar materials such as MoS{sub 2}. In this work, electrostatic doping by buried gates is used to study the electronic and optoelectronic properties of p-n junctions in exfoliated MoS{sub 2} flakes. Creating a controllable doping gradient across the device leads to the observation of the photovoltaic effect in monolayer and bilayer MoS{sub 2} flakes. For thicker flakes, strong ambipolar conduction enables realization of fully reconfigurable p-n junction diodes with rectifying current-voltage characteristics, and diode ideality factors as low as 1.6. The spectral response of the photovoltaic effect shows signatures of the predicted band gap transitions. For the first excitonic transition, a shift of >4{sub kB}T is observed between monolayer and bulk devices, indicating a thickness-dependence of the excitonic coulomb interaction.

  2. 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.

  3. 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. .

  4. Effects of Partial Phase Transformation on Characteristics of 9Cr Nanostructured Ferritic Alloy

    SciTech Connect (OSTI)

    Ji Hyun, Yoon; Byun, Thak Sang; Hoelzer, David T

    2014-01-01

    The core structures of future nuclear systems require tolerance to extreme irradiation, and some critical components, for example, the fuel cladding in Sodium-cooled Fast Reactors (SFRs), have to maintain mechanical integrity to very high doses of 200 -400 dpa at high temperatures up to 700 degrees C. The high Cr nanostructured ferritic alloys (NFAs) are under intense research worldwide as a candidate core material. Although the NFAs have some admirable characteristics for high-temperature applications, their crack sensitivity is very high at high temperatures. The fracture toughness of high strength NFAs is unacceptably low above 300 degrees C. The objective of this study is to develop processes and microstructures with improved high temperature fracture toughness and ductility. To optimize the afterextrusion heat treatment condition, both the computational simulation technique on phase equilibrium and the basic microstructural and mechanical characterization have been carried out. 9 Cr-NFA was produced by the mechanical alloying of pre-alloyed Fe-9Cr base metallic powder and yttria particles, and subsequent extrusion. The post-extrusion heat-treatments of various conditions were applied to the asextruded NFA. The tensile and fracture toughness tests were conducted for as-extruded and heat-treated samples at up to 700 degrees C. Fracture toughness of the NFA has increased by more than 40% at every testing temperature after heat-treatment in the inter-critical temperature range. The increment of fracture toughness of the NFA after post-extrusion heat-treatment is attributed to the increased strength at below 500 degrees C, and an increased ductility at 700 degrees C.

  5. GLADY CASSIT Y VANDALIA MURPHY CR EEK BU CKHN-CENT URY CLAY

    U.S. Energy Information Administration (EIA) Indexed Site

    GLADY CASSIT Y VANDALIA MURPHY CR EEK BU CKHN-CENT URY CLAY GLENVILLE N MINNORA JARVISVILLE FAR MINGTON PH ILIPPI BELIN GT ON WAYN ESBUR G PR UNT Y GLENVILLE S CAVE RUN TAYLOR DRAIN ROSEDALE ST MPT-N RMNT-SHK WESTON-JAN E LEW SWN DL-WID EN VADIS STANL EY DEKALB UNION TALLM AN SVILL E ASPINALL-FIN ST ER ZOLLARSVILLE WILBU R RAMSEY HEATER S BR IDGEPORT-PRUNT YTOWN ALEXAND ER LILLY FORK SH ERMAN HIRAM ST FK-BLST N CK BU RNS CH APEL S BR WN -LUM BER PORT CON INGS PR ATT BOSWELL REVEL ELK C REEK

  6. Audit Report: CR-B-02-01 | Department of Energy

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

    1 Audit Report: CR-B-02-01 October 15, 2001 Fixed-Price Contracting for Department of Energy Cleanup Activities As part of its Contract Reform effort, the Department of Energy (Department) acted to increase its use of fixed-price contracts. This shift was designed to increase the cost-effectiveness of operations. Since October 1994, the Office of Environmental Management (EM) has awarded a number of fixed-price contracts for environmental cleanup activities. In so doing, EM expected significant

  7. Audit Report: CR-B-98-01 | Department of Energy

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

    1 Audit Report: CR-B-98-01 October 8, 1997 Audit of the Internal Control Structure of the Department of Energy's Working Capital Fund The Subcommittee on Energy and Water Development of the Committee on Appropriations, in its report dated July 16, 1996, approved the implementation of a Working Capital Fund (Fund) at the U.S. Department of Energy. The Subcommittee also directed the Office of Inspector General to conduct periodic audits of the Fund. This audit was conducted to determine if the

  8. Audit Report: CR-B-99-02 | Department of Energy

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

    2 Audit Report: CR-B-99-02 September 30, 1999 Management of Unneeded Materials and Chemicals For more than 50 years, the U.S. Department of Energy (Department) and its contractors operated large production facilities and laboratories that acquired and produced directly or as by-products enormous amounts of non-nuclear materials such as sodium, lead, chemicals, and scrap metal. However, a mission change resulting from the end of the Cold War called into question the need for continued stockpiling

  9. Model independent interpretation of recent CR lepton data after AMS-02

    SciTech Connect (OSTI)

    Gaggero, Daniele; Maccione, Luca E-mail: luca.maccione@lmu.de

    2013-12-01

    We model the CR leptonic fluxes above 20 GeV in terms of a superposition of a standard and a charge symmetric extra component, which we generically describe as power-laws in momentum. We investigate under these hypotheses the compatibility between AMS-02, Fermi-LAT and PAMELA datasets on positron fraction, electron+positron spectrum and electron spectrum respectively. We find that it is possible to reconcile AMS and Fermi-LAT data within uncertainties, if energy-dependent effects are present in Fermi-LAT systematics. We also study possible deviations from charge symmetry in the extra component and find no compelling evidence for them.

  10. Nanostructured Cu-Cr alloy with high strength and electrical conductivity

    SciTech Connect (OSTI)

    Islamgaliev, R. K. Nesterov, K. M.; Bourgon, J.; Champion, Y.; Valiev, R. Z.

    2014-05-21

    The influence of nanostructuring by high pressure torsion (HPT) on strength and electrical conductivity in the Cu-Cr alloy has been investigated. Microstructure of HPT samples was studied by transmission electron microscopy with special attention on precipitation of small chromium particles after various treatments. Effect of dynamic precipitation leading to enhancement of strength and electrical conductivity was observed. It is shown that nanostructuring leads to combination of high ultimate tensile strength of 790–840 MPa, enhanced electrical conductivity of 81%–85% IACS and thermal stability up to 500 °C. The contributions of grain refinement and precipitation to enhanced properties of nanostructured alloy are discussed.

  11. Testing Novel CR-39 Detector Deployment System For Identification of Subsurface Fractures, Soda Springs, ID

    SciTech Connect (OSTI)

    McLing, Travis; Carpenter, Michael; Brandon, William; Zavala, Bernie

    2015-06-01

    The Environmental Protection Agency (EPA) has teamed with Battelle Energy Alliance, LLC (BEA) at Idaho National Laboratory (INL) to facilitate further testing of geologic-fracture-identification methodology at a field site near the Monsanto Superfund Site located in Soda Springs, Idaho. INL has the necessary testing and technological expertise to perform this work. Battelle Memorial Institute (BMI) has engaged INL to perform this work through a Work for Others (WFO) Agreement. This study continues a multi-year collaborative effort between INL and EPA to test the efficacy of using field deployed Cr-39 radon in soil portals. This research enables identification of active fractures capable of transporting contaminants at sites where fractures are suspected pathways into the subsurface. Current state of the art methods for mapping fracture networks are exceedingly expensive and notoriously inaccurate. The proposed WFO will evaluate the applicability of using cheap, readily available, passive radon detectors to identify conductive geologic structures (i.e. fractures, and fracture networks) in the subsurface that control the transport of contaminants at fracture-dominated sites. The proposed WFO utilizes proven off-the-shelf technology in the form of CR-39 radon detectors, which have been widely deployed to detect radon levels in homes and businesses. In an existing collaborative EPA/INL study outside of this workscope,. CR-39 detectors are being utilized to determine the location of active transport fractures in a fractured granitic upland adjacent to a landfill site at the Fort Devens, MA that EPA-designated as National Priorities List (NPL) site. The innovative concept of using an easily deployed port that allows the CR-39 to measure the Rn-222 in the soil or alluvium above the fractured rock, while restricting atmospheric Rn-222 and soil sourced Ra from contaminating the detector is unique to INL and EPA approach previously developed. By deploying a series of these inexpensive detector-casing combinations statistical samples of the Rn-222 flux can be measured, elucidating the most communicative fractures (i.e. fractures that are actively transporting water and gasses). The Rn-222 measurements can then be used as an input to create a more accurate conceptual model to be used for transport modeling and related cleanup activities. If the team’s approach is demonstrated to be applicable to a wide variety of rock types and soil conditions it might potentially offer significant cost saving without a reduction in data quality at Monsanto Superfund and other sites underlain by fracture-dominated bedrock.

  12. A low-temperature extraction-solvothermal route to the fabrication of micro-sized MoS{sub 2} spheres modified by Cyanex 301

    SciTech Connect (OSTI)

    Shi Huaqiang; Fu Xun . E-mail: fuxun4483@163.com; Zhou Xiaodong; Wang Debao; Hu Zhengshui

    2006-06-15

    Mono-dispersed molybdenum disulfide micro-spheres with the diameter of 1-3 {mu}m have been successfully synthesized via extraction-solvothermal method at 150 deg. C. The extractant Cyanex 301 (di-(2,4,4-trimethylpentyl) dithiophosphinic acid) acted as phase transferring agent, reductant, sulfur source and morphology-controlling agent in the whole procedure. The obtained MoS{sub 2} micro-spheres were characterized by XRD, EDS, SEM, TEM, HRTEM, IR, UV-Vis and TG, respectively. The influences of reaction conditions were discussed while a mechanism was proposed to explain the formation of the micro-spheres. Moreover, the tribological properties of liquid paraffin (LP) containing Cyanex 301-modified MoS{sub 2} micro-spheres were also evaluated on a four-ball machine, showing that the obtained MoS{sub 2} product was an excellent oil additive in LP and such lubricant had good anti-wear and friction-reducing properties. - Graphical abstract: Mono-dispersed MoS{sub 2} micro-spheres with the diameter of 1-3 {mu}m were synthesized in gasoline via extraction-solvothermal method at 150 deg. C. The MoS{sub 2} product could be well dispersed into organic solvents again and the tribological properties of liquid paraffin (LP) containing MoS{sub 2} micro-spheres were improved.

  13. Synthesis, characterization and evaluation of the photocatalytic performance of Ag-CdMoO{sub 4} solar light driven plasmonic photocatalyst

    SciTech Connect (OSTI)

    Adhikari, Rajesh; Malla, Shova; Gyawali, Gobinda; Sekino, Tohru; Lee, Soo Wohn

    2013-09-01

    Graphical abstract: - Highlights: Ag-CdMoO{sub 4} solar light driven photocatalyst was successfully synthesized. Photocatalyst exhibited strong absorption in the visible region. Photocatalytic activity was significantly enhanced. Enhanced activity was caused by the SPR effect induced by Ag nanoparticles. - Abstract: Ag-CdMoO{sub 4} plasmonic photocatalyst was synthesized in ethanol/water mixture by photo assisted co-precipitation method at room temperature. As synthesized powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UVVis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and BrunauerEmmettTeller (BET) surface area analyzer. Photocatalytic activity was evaluated by performing the degradation experiment over methylene blue (MB) and indigo carmine (IC) as model dyes under simulated solar light irradiation. The results revealed that the Ag-CdMoO{sub 4} showed the higher photocatalytic performance as compared to CdMoO{sub 4} nanoparticles. Dispersion of Ag nanoparticles over the surface of CdMoO{sub 4} nanoparticles causes the surface plasmon resonance (SPR) and enhances the broad absorption in the entire visible region of the solar spectrum. Hence, dispersion of Ag nanoparticles over CdMoO{sub 4} nanoparticles could be the better alternative to enhance the absorption of visible light by scheelite crystal family for effective photocatalysis.

  14. Reactive oxygen species mediate Cr(VI)-induced carcinogenesis through PI3K/AKT-dependent activation of GSK-3β/β-catenin signaling

    SciTech Connect (OSTI)

    Son, Young-Ok; Pratheeshkumar, Poyil; Wang, Lei; Wang, Xin; Fan, Jia; Kim, Dong-Hern; Lee, Ju-Yeon; Zhang, Zhuo; Lee, Jeong-Chae; Shi, Xianglin

    2013-09-01

    Cr(VI) compounds are known human carcinogens that primarily target the lungs. Cr(VI) produces reactive oxygen species (ROS), but the exact effects of ROS on the signaling molecules involved in Cr(VI)-induced carcinogenesis have not been extensively studied. Chronic exposure of human bronchial epithelial cells to Cr(VI) at nanomolar concentrations (10–100 nM) for 3 months not only induced cell transformation, but also increased the potential of these cells to invade and migrate. Injection of Cr(VI)-stimulated cells into nude mice resulted in the formation of tumors. Chronic exposure to Cr(VI) increased levels of intracellular ROS and antiapoptotic proteins. Transfection with catalase or superoxide dismutase (SOD) prevented Cr(VI)-mediated increases in colony formation, cell invasion, migration, and xenograft tumors. While chronic Cr(VI) exposure led to activation of signaling cascades involving PI3K/AKT/GSK-3β/β-catenin and PI3K/AKT/mTOR, transfection with catalase or SOD markedly inhibited Cr(VI)-mediated activation of these signaling proteins. Inhibitors specific for AKT or β-catenin almost completely suppressed the Cr(VI)-mediated increase in total and active β-catenin proteins and colony formation. In particular, Cr(VI) suppressed autophagy of epithelial cells under nutrition deprivation. Furthermore, there was a marked induction of AKT, GSK-3β, β-catenin, mTOR, and carcinogenic markers in tumor tissues formed in mice after injection with Cr(VI)-stimulated cells. Collectively, our findings suggest that ROS is a key mediator of Cr(VI)-induced carcinogenesis through the activation of PI3K/AKT-dependent GSK-3β/β-catenin signaling and the promotion of cell survival mechanisms via the inhibition of apoptosis and autophagy. - Highlights: • Chronic exposure to Cr(VI) induces carcinogenic properties in BEAS-2B cells. • ROS play an important role in Cr(VI)-induced tumorigenicity of BEAS-2B cells. • PI3K/AKT/GSK-3β/β-catenin signaling involved in Cr(VI) carcinogenesis. • The inhibition of apoptosis and autophagy contributes to Cr(VI) carcinogenesis.

  15. Mo{sub 6}Se{sub 8}-cluster-based superconducting compounds Cs{sub 2}Mo{sub 12}Se{sub 14} and Rb{sub 4}Mo{sub 18}Se{sub 20}: Evidence for a strongly correlated and anisotropic electron system

    SciTech Connect (OSTI)

    Brusetti, R.; Laborde, O.; Sulpice, A.; Calemczuk, R.; Potel, M.; Gougeon, P.

    1995-08-01

    We studied the normal and superconducting states of the title compounds by measuring the conductivity and magnetization of single crystals and powder samples. From the upper and lower critical fields we deduced the characteristic lengths and thermodynamical fields. These results are borne out by our specific-heat measurements. We recognize in these compounds many features of the Chevrel-phase superconductors, including very small coherence lengths and strong-coupling-like effects. However, we show that the electron system is much more anisotropic and still less delocalized in these materials where the Mo{sub 6}Se{sub 8} clusters have condensed in Mo{sub 6{ital n}}Se{sub 6{ital n}+2} finite chains. This condensation is accompanied by an enhancement of the magnetic response whereas the lengthening of the chains leads to a counteracting reduction of the density of carriers. This indicates that superconductivity is built upon highly correlated molecular states. Reviewing the available data on the other Chevrel-cluster-based superconductors confirms this picture and suggests that the small coherence lengths reflect the local character of the electron pairing. This comparison also shows that forming finite chains of Mo{sub 6}Se{sub 8} clusters makes the electron correlations more repulsive and pushes the electron system near the borderline between superconductivity and magnetism. In this respect these compounds could provide valuable complementary information on issues which are at the center of the research upon high-{ital Y}{sub {ital c}} superconductivity.

  16. Technical assumption for Mo-99 production in the MARIA reactor. Feasibility study

    SciTech Connect (OSTI)

    Jaroszewicz, J.; Pytel, K.; Dabkowski, L.; Krzysztoszek, G. [Institute of Atomic Energy, 05-400 Otwock-Swierk (Poland)

    2008-07-15

    The main objective of U-235 irradiation is to obtain the Tc-99m isotope which is widely used in the domain of medical diagnostics. The decisive factor determining its availability, despite its short life time, is a reaction of radioactive decay of Mo-99 into Tc- 99m. One of the possible sources of molybdenum can be achieved in course of the U-235 fission reaction. The paper presents activities and the calculations results obtained upon the feasibility study on irradiation of U-235 targets for production of molybdenum in the MARIA reactor. The activities including technical assumption were focused on performing calculation for modelling of the target and irradiation device as well as adequate equipment and tools for processing in reactor. It has been assumed that the basic component of fuel charge is an aluminium cladded plate with dimensions of 40x230x1.45 containing 4.7 g U-235. The presumed mode of the heat removal generated in the fuel charge of the reactor primary cooling circuit influences the construction of installation to be used for irradiation and the technological instrumentation. The outer channel construction for irradiation has to be identical as the standard fuel channel construction of the MARIA reactor. It enables to use the existing slab and reactor mounting sockets for the fastening of the molybdenum channel as well as the cooling water delivery system. The measurement of water temperature cooling a fuel charge and control of water flow rate in the channel can also be carried out be means of the standard instrumentation of the reactor. (author)

  17. Application of U10Mo Fuel for Space Fission Power Applications - White Paper

    SciTech Connect (OSTI)

    James Werner

    2014-07-01

    A novel reactor design has been proposed for space applications to provide hundreds of watts to one or two kilowatts of electrical power. The reactor concept proposed uses the alloy U10Mo (uranium with 10 weight percent molybdenum) as the fuel. This fuel was selected for its high uranium density, high thermal conductivity, and excellent neutronic characteristics for this application. The core is surrounded by a BeO reflector. Heat is carried from the reactor by liquid metal heat pipes. A shadow shield of LiH tungsten is also utilized to reduce the neutron and gamma radiation dose to the rest of the spacecraft. This design represents a best effort at minimizing the complexity of the fission system and reducing the mass of the system. The compact nature of the block UMo core and BeO radial reflector allows the reactor diameter to be as small as practical while still meeting the neutronic and thermal power demands. This directly results in a reduced shield mass since the reactor diameter dictates the footprint of the radiation shield. The use of heat pipes offers a straightforward primary heat transport approach using proven liquid-metal heat pipe technology. Further, the elimination of a liquid core coolant system heat transport components, both at the reactor side and radiator side, contributes to reducing the total part-count and lowering system mass. The proposed reactor is using a fuel that is being developed by DOE, but there are significant differences in the fuels enrichment, operating conditions and the physical shape of the fuel itself. This paper attempts to highlight some of the basic consideration and needs that would be expected to be met in developing this fuel and qualifying it for use.

  18. Nano-Scale Fission Product Phases in an Irradiated U-7Mo Alloy Nuclear Fuel

    SciTech Connect (OSTI)

    Dennis Keiser, Jr.; Brandon Miller; James Madden; Jan-Fong Jue; Jian Gan

    2014-09-01

    Irradiated nuclear fuel is a very difficult material to characterize. Due to the large radiation fields associated with these materials, they are hard to handle and typically have to be contained in large hot cells. Even the equipment used for performing characterization is housed in hot cells or shielded glove boxes. The result is not only a limitation in the techniques that can be employed for characterization, but also a limitation in the size of features that can be resolved The most standard characterization techniques include light optical metallography (WM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). These techniques are applied to samples that are typically prepared using grinding and polishing approaches that will always generate some mechanical damage on the sample surface. As a result, when performing SEM analysis, for example, the analysis is limited by the quality of the sample surface that can be prepared. However, a new approach for characterizing irradiated nuclear fuel has recently been developed at the Idaho National Laboratory (INL) in Idaho Falls, Idaho. It allows for a dramatic improvement in the quality of characterization that can be performed when using an instrument like an SEM. This new approach uses a dual-beam scanning microscope, where one of the beams isa focused ion beam (FIB), which can be used to generate specimens of irradiated fuel (-10m x 10m) for microstructural characterization, and the other beam is the electron beam of an SEM. One significant benefit of this approach is that the specimen surface being characterized has received much less damage (and smearing) than is caused by the more traditional approaches, which enables the imaging of nanometer sized microstructural features in the SEM. The process details are for an irradiated low-enriched uranium (LEU) U-Mo alloy fuel Another type of irradiated fuel that has been characterized using this technique is a mixed oxide fuel.

  19. Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering

    SciTech Connect (OSTI)

    Gawlitza, Peter; Cambie, Rossana; Dhuey, Scott; Gullikson, Eric; Warwick, Tony; Braun, Stefan; Yashchuk, Valeriy; Padmore, Howard

    2012-01-23

    Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects we used an ionbeam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr{sup +} ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the Linear Continuous Model of film growth.

  20. Removal of Radioactive Nuclides from Mo-99 Acidic Liquid Waste - 13027

    SciTech Connect (OSTI)

    Hsiao, Hsien-Ming; Pen, Ben-Li

    2013-07-01

    About 200 liters highly radioactive acidic liquid waste originating from Mo-99 production was stored at INER (Institute of Nuclear Energy Research). A study regarding the treatment of the radioactive acidic liquid waste was conducted to solve storage-related issues and allow discharge of the waste while avoiding environmental pollution. Before discharging the liquid waste, the acidity, NO{sub 3}{sup -} and Hg ions in high concentrations, and radionuclides must comply with environmental regulations. Therefore, the treatment plan was to neutralize the acidic liquid waste, remove key radionuclides to reduce the dose rate, and then remove the nitrate and mercury ions. Bench tests revealed that NaOH is the preferred solution to neutralize the high acidic waste solution and the pH of solution must be adjusted to 9?11 prior to the removal of nuclides. Significant precipitation was produced when the pH of solution reached 9. NaNO{sub 3} was the major content in the precipitate and part of NaNO{sub 3} was too fine to be completely collected by filter paper with a pore size of approximately 3 ?m. The residual fine particles remaining in solution therefore blocked the adsorption column during operation. Two kinds of adsorbents were employed for Cs-137 and a third for Sr-90 removal to minimize cost. For personnel radiation protection, significant lead shielding was required at a number of points in the process. The final process design and treatment facilities successfully treated the waste solutions and allowed for environmentally compliant discharge. (authors)