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Pie"eFi5e Hinea ótiTiUation. I.R. de Farias JR., M. ?hao, and H. ?hao. State University of New York at jumalo. {defariasy m|haoy |hon??ia}@??ffalo.ed?.
Asymmetry of radiation damage properties in Al-Ti nanolayers...
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reveal significant and important asymmetries in defect production with sim60% of vacancies created in Al layers compared to Ti layers within the Al-Ti multilayer system. The...
Gasoline and Diesel Fuel Update (EIA)
0.00-1.99 0.00-1.99 2.00-2.99 3.00-3.99 4.00-4.99 5.00-5.99 6.00-6.99 7.00+ NJ WY AK AL CA AR CO CT DE FL GA HI ID KS IL IN IA IA KY LA ME MI MA MD MN MS MT MO NE ND OH NV NM NY NH NC OK OR PA RI SC SD TN TX UT VT WA WV WI AZ VA DC 0.00-1.99 2.00-2.99 3.00-3.99 4.00-4.99 5.00-5.99 6.00-6.99 7.00+ 18. Average Price of Natural Gas Delivered to U.S. Onsystem Industrial Consumers, 1996 (Dollars per Thousand Cubic Feet) Figure 19. Average Price of Natural Gas Delivered to U.S. Electric Utilities, 1996 (Dollars per Thousand Cubic Feet) Figure Sources: Federal Energy Regulatory Commission (FERC), Form FERC-423, "Monthly Report of Cost and Quality of Fuels for Electric Plants," and Energy Information Administration (EIA), Form EIA-176, "Annual Report of Natural and Supplemental Gas Supply and Disposition." Note: In 1996, consumption of natural gas for agricultural use
Structure and ductility of TiAl
The effect of structural factors (grain size and grain boundary structure) and strain rate on the deformation mechanism and ductility of TiAl in the temperature range of brittle-to-ductile transition and at room temperature was systematically investigated. It has been established that it is possible to substantially affect the deformation mechanism and ductility of this intermetallic by controlling structural factors, particularly the grain size, and varying the strain rate.
Imayev, R.; Salishchev, G.; Imayev, V.; Shagiev, M.; Kuznetzov, A. [Inst. for Metals Superplasticity Problems, Ufa (Russian Federation)
Nanolayered CrAlTiN and multilayered CrAlTiN¢AlTiN coatings for solid particle erosion protection
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Abstract Applying hard coatings on airfoil surfaces is proven to be an effective approach to mitigating erosion damage to engine components. Nanolayered or multilayered coatings, because of their capability of tailoring hardness and toughness through modifications in the chemistry and architecture of layer constituents, have been explored as potential candidates for this specific application. In this study, nanolayered CrAlTiN (CrN/AlTiN) coatings with different modulation periods, along with multilayered CrAlTiN¢AlTiN coatings having different number of layers and different thickness of individual layers, were fabricated, characterized and evaluated. All the coatings significantly outperformed the CrN baseline in erosion resistance, and their performance was strongly affected by the bilayer period of the nanolayered coatings or the layer architectural characteristics of multilayered coatings.
Q. Yang; R. McKellar
Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal structures
Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal-04843 (Metals Program) and Praveen Sinha Fund for Physics Research. L12 DO22 DO23 Cu3Au Al3Ti Al3Zr #12;Outline ┬Ę Indium was doped in samples of Al3V and Al3Ti (Al3Ti structure) and Al3Zr (Al3Zr structure) by arc
Collins, Gary S.
TI--CR--AL--O thin film resistors
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.
Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solana Beach, CA)
Dynamic recrystallization and superplasticity in TiAl
The effect of structural factors (grain size, grain boundary structure and fraction of the second phase) on dynamic recrystallization and superplasticity in the TiAl intermetallic alloy was studied. The possibilities of the formation of submicrocrystalline structure and the abrupt decrease of the superplastic temperature were shown. It was established that the occurrence of dynamic recrystallization and superplastic flow led to the formation of homogeneous microstructure and the improvement of low-temperature ductility in TiAl.
Salishchev, G.; Imayev, R.; Imayev, V.; Shagiev, M. [Inst. for Metals Superplasticity Problems, Ufa (Russian Federation)
Carbide precipitation in gamma-TiAl alloys
Carbide precipitation in gamma-TiAl is observed and found to involve the formation of coherent, rod-shaped perovskite precipitates as a metastable transition phase. At temperatures above 750 deg C, the formation of plate-shaped H-phase particles on dislocations and grain boundaries is accompanied by dissolution of the perovskite precipitate dispersions. This temperature regime includes possible service temperatures for gamma-TiAl-based alloys. 10 refs.
Chen, S.; Beaven, P.A.; Wagner, R. (GKSS-Forschungszentrum Geesthacht GmbH, (Germany))
Laser Cladding of TiAl Intermetallic Alloy on Ti6Al4V -Process Optimization and Properties
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Abstract In order to improve Ti6Al4V high-temperature resistance and its tribological properties, the deposition of TiAl intermetallic (Ti-48Al-2Cr-2Nb) coating on a Ti6Al4V substrate by coaxial laser cladding has been investigated. Laser cladding by powder injection is an emerging laser material processing technique that allows the deposition of thick protective coatings on substrates,using a high power laser beam as heat source. Laser cladding is a multiple-parameter-dependent process. The main process parameters involved (laser power, powder feeding rate, scanning speed and preheating temperature) has been optimized. The microstructure and geometrical quantities (clad area and dilution) of the coating was characterized by optical microscopy and scanning electron microscopy (SEM). In addition the cooling rate of the clad during the process was measured by a dual-color pyrometer. This result has been related to defectology and mechanical coating properties.
B. Cßrcel; A. Serrano; J. Zambrano; V. Amig¾; A.C. Cßrcel
Compton Profile Study of Intermetallic Ti{sub 3}Al
The Compton scattering measurement on intermetallic alloy Ti{sub 3}Al is reported in this work. The measurement is made using 59.54 keV gamma-rays from Am{sup 241} source. Theoretical calculation of Compton profile is also performed employing CRYSTAL code within the framework of density functional theory to compare with the measurement. The theoretical profile of the alloy is also synthesized following the superposition model taking the published Compton profiles of elemental solids from the APW method. The experimental study of charge transfer in the alloys has also been done by performing the experimental Compton profile measurements on Ti and Al following the superposition model and charge transfer from Al to Ti is clearly seen on the alloy formation.
Vyas, V.; Sharma, G. [Department of Physics, Banasthali University, Banasthali-304022 (India); Mishra, M. C.; Sharma, B. K. [Department of Physics, University of Rajasthan, Jaipur-302004 (India); Joshi, K. B. [Department of Physics, University College of Science, M.L.Sukhadia University, Udaipur-313 002 (India)
Investigation of the reaction zone between TiAl and Mo
Pure Mo was incorporated in TiAl matrix via two different routes: (1) hot pressing of alternately sandwiched Ti-Al sheets and Mo foils; and (2) coextrusion and heat treatment of Ti-Al green compact and Mo rod. The reaction zone between TiAl and Mo is found to contain two intermetallic phases: {beta}-(Mo,Ti)Al and {rho}-(Mo,Ti){sub 3}Al. The {beta}-{rho} boundary is incoherent, whereas the TiAl-{beta} and {rho}-Mo boundaries are semicoherent. The reaction zone grows with increasing heat-treatment time in a parabolic form. The incorporated Mo exhibits lower hardness than the TiAl matrix, implying that ductilizing and toughening of TiAl by introducing Mo as a ductile reinforcement are possible.
Hsu, F.Y.; Klaar, H.J. [Aachen Univ. of Technology (Germany); Wang, G.X. [Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering; Pirwitz, F. [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research
Textures and plastic anisotropy in gamma-TiAl
Specimens of a Ti-36 wt pct Al alloy consisting primarily of gamma TiAl were deformed in compression at 450 C and in rolling at 1050 C. The textures of the deformed specimens were measured and analyzed in terms of orientation distribution functions. After hot rolling, the texture is strongly influenced by recrystallization and shows a cube-like component with an alignment of the c-axis with the transverse direction. The measured compression textures are compared with those simulated on the basis of the Taylor theory of polycrystal deformation. 36 refs.
Hartig, C.H.; Fang, X.F.; Mecking, H.; Dahms, M. (Hamburg, Technische Universitaet, (Germany) GKSS-Forschungszentrum Geesthacht GmbH, (Germany))
Site-Dependent Activity of Atomic Ti Catalysts in Al-Based Hydrogen Storage Materials
Site-Dependent Activity of Atomic Ti Catalysts in Al-Based Hydrogen Storage Materials Abdullah Al storage processes. Here we analyze the role of atomic Ti catalysts in the hydrogenation of Al-based hydrogen storage materials. We show that Ti atoms near the Al surface activate gas-phase H2, a key step
Ciobanu, Cristian
Topotaxial growth of Ti{sub 2}AlN by solid state reaction in AlN/Ti(0001) multilayer thin films
The formation of Ti{sub 2}AlN by solid state reaction between layers of wurtzite-AlN and {alpha}-Ti was characterized by in situ x-ray scattering. The sequential deposition of these layers by dual magnetron sputtering onto Al{sub 2}O{sub 3}(0001) at 200 deg. C yielded smooth, heteroepitaxial (0001) oriented films, with abrupt AlN/Ti interfaces as shown by x-ray reflectivity and Rutherford backscattering spectroscopy. Annealing at 400 deg. C led to AlN decomposition and diffusion of released Al and N into the Ti layers, with formation of Ti{sub 3}AlN. Further annealing at 500 deg. C resulted in a phase transformation into Ti{sub 2}AlN(0001) after only 5 min.
Hoeglund, C.; Beckers, M.; Schell, N.; Borany, J. v.; Birch, J.; Hultman, L. [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linkoeping University, S-581 83 Linkoeping (Sweden); GKSS Research Center Geesthacht, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linkoeping University, S-581 83 Linkoeping (Sweden)
Thermal stability and oxidation resistance of TiCrAlYO coatings...
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stability and oxidation resistance of TiCrAlYO coatings on SS430 for solid oxide fuel cell interconnect applications. Thermal stability and oxidation resistance of TiCrAlYO...
Superplastic foaming of titanium and Ti-6Al-4V
Solid-state foaming of metals can be achieved by hot-isostatic pressing of powders in presence of argon followed by expansion of the resulting high-pressure argon bubbles at ambient pressure and elevated temperature. This foaming technique was first demonstrated by Kearns et al. for Ti-6Al-4V, but is limited by its low creep rate and ductility, which lead to early cell wall fracture. The authors address these issues by performing the foaming step under superplastic conditions. Rather than using microstructural superplasticity (requiring fine grains which are difficult to achieve in porous powder-metallurgy materials), they used transformation superplasticity, which occurs at all grain sizes by biasing with a deviatoric stress (from the pore pressure) of internal stresses (from the allotropic mismatch during thermal cycling about the allotropic temperature range). As compared to control experiments performed under isothermal creep conditions, superplastic foaming under temperature cycling of unalloyed titanium and alloyed Ti-6Al-4V led to a significantly higher pore volume fraction and higher foaming rate.
Dunand, D.C. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Teisen, J. [Swiss Federal Inst. of Tech., Zuerich (Switzerland). Dept. of Materials
On elongated stacking fault loops in TiAl
Depending upon strain, load orientation, alloy composition and test temperature, the deformation microstructure of TiAl contains a varied density of stacking faults ribbons. The presence of these ribbons is correlated with that of superdislocations with 1/2{l_angle}112[square bracket] Burgers vector. They are elongated along any of the {l_angle}011[square bracket] directions. The present paper focuses on their formation mechanism, especially on the reasons which make that such dipolar defects, though intrinsically unstable, tend to exhibit a reasonably constant width.
Hug, G.; Veyssiere, P. [CNRS-ONERA, Chatillon (France)
Low thermal expansion behavior and thermal durability of ZrTiO4Al2TiO5Fe2O3 ceramics between 750 and 1400
2002 Abstract The thermal-shock-resistant materials in the system Al2TiO5┬ŁZrTiO4 (ZAT) were synthesized Aluminum titanate (Al2TiO5) is well-known as an excellent thermal shock-resistant material, resulting from. All rights reserved. Keywords: Al2TiO5; Thermal expansion; Thermal shock resistance 1. Introduction
Cao, Guozhong
Influence of Si content on microstructure of TiAl alloys
A systematic study of four ternary TiAl-based alloys with constant Ti content of 52.2 at. % and variable Si content ranging from 0.3 to 2.7 at. % (Al in balance) was conducted. The alloys were prepared from elemental powders via a route including powder mixing, precompaction, cold extrusion, and reactive hot-isostatic pressing. All investigated alloys contain the intermetallic compounds {gamma}-TiAl, {alpha}{sub 2}-Ti{sub 3}Al, and {zeta}-Ti{sub 5}(Si,Al){sub 3}. The microstructure can be described as a duplex structure (i.e., lamella {gamma}/{alpha}{sub 2} regions distributed in a {gamma} matrix) containing {zeta} precipitates. With increasing Si content, the number of primary {zeta} precipitates increased and the {gamma} grain size became finer while the lamellar volume fraction decreased slightly.
Hsu, F.Y.; Klaar, H.J. [Aachen Univ. of Technology (Germany). Central Lab. of Electron Microscopy] [Aachen Univ. of Technology (Germany). Central Lab. of Electron Microscopy; Wang, G.X. [Zhejiang Univ., Hangzhou (China)] [Zhejiang Univ., Hangzhou (China); Dahms, M. [GKSS Research Center, Geesthacht (Germany)] [GKSS Research Center, Geesthacht (Germany)
Synthesis and structure of Al clusters supported on TiO2,,110...: A scanning tunneling microscopy study
Synthesis and structure of Al clusters supported on TiO2,,110...: A scanning tunneling microscopy, Texas 77843-3255 Received 14 October 1997; accepted 6 April 1998 Al clusters supported on TiO2(110) have been investigated using scanning tunneling microscopy. Al interacts strongly with the TiO2(110) surface
Goodman, Wayne
On the Liquid/Solid Phase Equilibria in the Al-Rich Corner of the Al-Si-Ti Ternary System
On the Liquid/Solid Phase Equilibria in the Al-Rich Corner of the Al-Si-Ti Ternary System O; published online February 5, 2014) The nature of liquid-solid phase equilibria in the Al-rich corner of the Al-Si-Ti system are determined by drawing three isothermal sections at 620, 680 and 727 ┬░C
Paris-Sud XI, Universit├® de
Flat panel display using Ti-Cr-Al-O thin film
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.
Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solan Beach, CA)
Atomistic simulation of dislocation core structures in ordered TiAl
Interatomic potentials of the Embedded Atom type were used in the simulation of the dislocation core structures in TiAl. Different orientations of the dislocation line were simulated for the most commonly observed TiAl slip systems. Low-temperature dislocation behavior is interpreted in terms of ordinary dislocation motion. The effect of applied stress on the shape of the dislocation core and its mobility is examined as well. For the superdislocations several possible types of dissociations were studied.
Panova, J.; Farkas, D. [Virginia Polytechnic Inst., Blacksburg, VA (United States). Dept. of Materials Science and Engineering
Preparation and properties of Al-PILC supported SO42?/TiO2 superacid catalyst
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SO42?/TiO2/Al-pillared clay (ST/Al-PILC) superacid catalyst was prepared by loading active component SO42?/TiO2 on Al-pillared clay. The texture structure properties of the catalyst were studied by means of X-ray powder diffraction and the adsorption of N2. Acidity properties of the catalyst were tested by Hammett indicator method and FT-IR spectra of absorbed pyridine technique. The characterization results indicated that Al-PILC carrier could inhibit the formation of anatase TiO2 and the transformation of anatase TiO2 into rutile TiO2. ST/Al-PILC catalyst possesses both Lewis and Br÷nsted acid sites, and the number of acid sites on ST/Al-PILC is much larger than that on Al-PILC carrier, but its acid strength is lower than that of ST. Experimental results show that ST/Al-PILC is an effective catalyst for esterification of n-pentanol with benzoic acid.
Yue-Xiu Jiang; Xiao-Mei Chen; Yun-Fen Mo; Zhang-Fa Tong
Short-range order of low-coverage Ti/Al,,111...: Implications for hydrogen storage in complex metal hydrides
Short-range order of low-coverage Ti/Al,,111...: Implications for hydrogen storage in complex metal-coverage Ti atoms on Al 111 as a model surface system for transition metal doped alanate hydrogen storage the dissociative chemisorption of hydrogen in Ti-doped alanate storage materials. ┬® 2007 American Institute
Ciobanu, Cristian
Investigation of the {gamma}-Ti(Cr,Al)2 phase at 800 C and 1000 C
A section of the Ti-Al-Cr ternary system, centered around the {gamma}-TiCr{sub 2} phase was examined using five quenched bulk alloy samples and three diffusion couples. Due to the sluggishness of diffusion both at 800 and 1,000 C in the TiCr{sub 2} phase fields, the heat treatment produced a state of near-equilibrium in the samples rather than complete equilibrium, as desired. However, as previous studies have made use of similar, or shorter, processing schedules, the results of the present study should be considered as valid as the earlier works. As a confirmation of the phase composition obtained from the near-equilibrium bulk alloys, the results of a diffusion couple analysis, yielded similar compositions. It is clear, based on the above results that the {gamma}-TiCr{sub 2}, with a C14 crystal structure, does indeed extend into the Ti-Al-Cr ternary system as indicated by Suprunenko et al. The {gamma}-TiCr{sub 2} phase advances into the ternary as the b solid solution pulls away from the Ti-Cr binary system with decreasing temperature. Solubility into the ternary system is made possible by Al atoms substituting onto Cr sites, as is observed for the Al-Cr-Nb ternary system. Although the solubility of the {gamma}-TiCr{sub 2} phase extends from about 3--19at% Al at 1,000 C and from 6--24at% Al at 800 C, the exact limits of solubility are yet to be determined.
Jewett, T.J.; Dahms, M. [GKSS Research Centre, Geesthacht (Germany)] [GKSS Research Centre, Geesthacht (Germany)
Simply AlF3-treated Li4Ti5O12 composite anode materials for stable...
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Li4Ti5O12 composite anode materials for stable and ultrahigh power lithium-ion batteries. Simply AlF3-treated Li4Ti5O12 composite anode materials for stable and ultrahigh...
Microstructure and fracture toughness aspects of diffusion bonded interface between Ti and Al
This study was undertaken to identify the microstructural characteristics of the intermetallic phases formed at the interface during the bonding process and determine the mechanical properties of Ti-Al dissimilar diffusion bonded joints, namely strength and fracture toughness. Furthermore, the effect of the intermetallic phases on the strength and fracture toughness of the joint was also determined. The effect of strength mis-match between Ti and Al on the fracture process will also be discussed. This investigation is the first phase of a larger project on the characterization of the intermetallics formed and their influence on strength and fracture toughness of the joints between TiAl-TiAl. A series of diffusion bonds of 25mm {times} 25 mm thick Ti bars were produced using aluminum foils of different thicknesses as interlayer. The bonded joints were tested to determine the fracture toughness properties of the interface formed and the effect of intermetallic phase formation on the fracture toughness was evaluated. Four-point bend specimens containing a crack introduced into the interface during the bonding process were tested to determine the diffusion-bonded interface fracture toughness. Tensile tests of the joints were also conducted to determine their strengths. The bonding conditions required to obtain a sound joint between Ti and Al were also evaluated.
Cam, G.; Dobi, D.; Kocak, M. [GKSS Research Center, Geesthacht (Germany); Heikinheimo, L.; Siren, M. [VTT Manufacturing Technology, Espoo (Finland)
Al¢Ge¢Ti: Phase equilibria and structural characterization of new ternary compounds
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Abstract Phase equilibria of Al¢Ge¢Ti have been investigated using scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and differential thermal analysis (DTA). Partial isothermal sections at 400Ā░C, 520Ā░C and 1000Ā░C were obtained with focus on the titanium-poor part up to 50Āat.% titanium. Three ternary compounds were found to exist. The compound Al3GeTi (?1) crystallizes in an own structure type (P4/nmm, tP10). Two structurally closely related compounds were found at the composition Al1?xGe1+xTi: ?2 (0.61Ā?ĀxĀ?Ā0.73), Al4Si5Zr3-type, I41/amd, tI24 and ? 2 ? (0.36Ā?ĀxĀ?Ā0.57), Si2Zr-type, Cmcm, oC12. DTA data were used to construct a ternary reaction scheme (Scheil diagram) up to approximately 1300Ā░C, a partial liquidus projection and two vertical sections, at 10Āat.% Ti and at a constant Al:Ti ratio of 1:1. A total number of 12 ternary invariant reactions were identified.
Roland W. Bittner; Matthias G³rth; Liliana I. Duarte; Christian Leinenbach; Herta S. Effenberger; Klaus W. Richter
Effect of Reactive Sputtering Parameters on TiAlN Nanocoating Structure and Morphology
The effect of substrate bias and nitrogen flow rate on the TiAlN nanocoating structure and morphology has been investigated by using reactive unbalance DC magnetron sputtering. TiAlN nanocoating was deposited on the tungsten carbide insert tool and the structure and morphology were characterized by using XRD and AFM, respectively. The substrate bias was varied between 0 to -221 V and the nitrogen flow rate was varied between 30 to 72 sccm. The results showed that the structure of TiAlN nanocoating consisted of mainly (111) and (200) plane. The structure was significatly influenced by substrate bias in promoting finer crystal size and increased crystal plane spacing while the rms roughness of nanocoating was influenced by substrate bias and nitrogen flow rate.
Budi, Esmar [Jurusan Fisika FMIPA Universitas Negeri Jakarta Jl. Pemuda No. 10 Rawamangun Jakarta 13220 (Indonesia); Razali, M. Mohd.; Nizam, A. R. Md. [Faculty of Manufacturing Engineering Universiti Teknikal Malaysia Melaka (UTeM) Karung Berkunci No 1752 Pejabat Pos Durian Tunggal 76109 Melaka (Malaysia)
Preparation of Al2O3/TiO2-containing Coating on Aluminium Alloys by Micro-arc Oxidation
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TiO2-containing ceramic coatings were deposited on the surface of aluminium alloys by micro-arc oxidition. Surface and cross-section topograph of ceramic coating were observed using scanning electron microscopy (SEM). The phase composition of ceramic ... Keywords: Micro-arc oxidation, TiO2 additive, Al2O3/TiO2 phase, antiwear behavior
Cheng Gao; Jinyong Xu; Yusheng Lan; Yonghui Ma; Weixiang Su; Yajuan Liu
Lattice variations of Ti-6Al-4V alloy with hydrogen content
Effect of hydrogen content on the lattice parameter of Ti-6Al-4V alloy has been investigated by X-ray diffraction. The experimental results show that the solution of hydrogen in the Ti-6Al-4V alloy affects significantly on the lattice parameters of {alpha}, {beta} and {delta} phases, especially the {beta} phase. Furthermore, the critical hydrogen content of {delta} hydride formation for Ti-6Al-4V alloy is 0.385 wt.%. When the hydrogen content is lower than the critical hydrogen content, the {delta} hydride cannot precipitate and the lattice parameter ({alpha}) of {beta} phase linearly increases with the increasing of hydrogen content. When the hydrogen content is higher than the critical hydrogen content, the {delta} hydride precipitates and the lattice parameter ({alpha}) of {beta} phase varies inconspicuously with hydrogen content. In addition, the effects of lattice variations and {delta} hydride formation on microstructure are discussed. The {alpha}/{beta} interfaces of lamellar transformed {beta} phase become fuzzy with the increasing of hydrogen content because of the lattice expansion of {beta} phase. Compared with that of the Ti-6Al-4V alloy at low hydrogen content ({<=} 0.385 wt.%), the contrasts of primary {alpha} phase and transformed {beta} phase of Ti-6Al-4V alloy at high hydrogen content ({>=} 0.385 wt.%) were completely reversed due to the formation of {delta} hydride. - Research Highlights: {yields} A novel method for determining {delta} hydride in Ti-6Al-4V alloy is presented. {yields} The critical hydrogen content of {delta} hydride formation is 0.385 wt.%. {yields} The lattice parameter of {beta} phase can be expressed as follows: a=0.323(1+9.9x10{sup -2}C{sub H}) . {yields} Precipitation of {delta} hydride has a significant influence on the microstructure. {yields} The {alpha}/{beta} interfaces of transformed {beta} phase became fuzzy in the hydrogenated alloy.
Zhu Tangkui, E-mail: email@example.com; Li, Miaoquan, E-mail: firstname.lastname@example.com
Photodissociation measurements of bond dissociation energies: D0(Al2-Al), D0(TiO -Mn), and D0(V2 -V)
Photodissociation measurements of bond dissociation energies: D0(Al2-Al), D0(TiO -Mn), and D0(V2 -VV was obtained by adding the energy of the 4 A2 state to the measured predissociation threshold. For Ti studies may be used to measure bond lengths and deduce term symbols. As one proceeds to higher energies
Morse, Michael D.
Microstructure and tensile properties of spray formed gamma Ti48.9at.%Al
Until now only a limited number of spray forming experiments on TiAl were reported, and the mechanical data of sprayed material of these alloys are rather rare. In this paper, the application of the EIGA-technique (Electrode Induction Melting Gas Atomization) for spray forming of binary Ti48.9Al(at.%) is reported. Sprayed deposits, obtained under near optimum conditions are tensile tested at room temperature and microstructurally characterized. The results are compared to similar alloys obtained by other process routes.
Liu, K.W. [GKSS Forschungszentrum, Geesthacht (Germany)] [GKSS Forschungszentrum, Geesthacht (Germany); [Univ. of Science and Technology, Beijing (China). State Kay Lab for Advanced Metals and Materials; Gerling, R.; Schimansky, F.P. [GKSS Forschungszentrum, Geesthacht (Germany)] [GKSS Forschungszentrum, Geesthacht (Germany)
Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4
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Effect of Ti for Effect of Ti for Hydrogen Cycling in NaAlH 4 Mei-Yin Chou School of Physics Georgia Institute of Technology (DE-FG02-05ER46229) Acknowledgment: Yan Wang, Roland Stumpf Why is NaAlH 4 interesting? A viable candidate for hydrogen-storage material: High theoretical weight-percent hydrogen content of 5.55% and low cost But (before 1997) Dehydrogenation occurs at high temperature; rehydrogenation is difficult. Bogdanovic and Schwickardi, 1997 Hydrogen can be reversibly absorbed and desorbed from NaAlH 4 under moderate conditions by the addition of catalysts (compounds containing Ti, Zr, etc.) High Hydrogen Contents in Complex Hydrides Hydride wt% Hydride wt% Be(BH 4 ) 2 20.8 Mg(AlH 4 ) 2 9.3 LiBH 4 18.2 Ca(AlH 4 ) 2 7.9 Mg(BH 4 ) 2 14.9 KBH 4 7.5 Ca(BH 4 ) 2 11.6 NaAlH 4 7.5 NaBH4 10.7 Ga(AlH
Application of FIB microsampling technique to long-period ordered TiAl single crystal with composition gradient
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......and 3 Department of Materials Science and Engineering...for Electronics and Materials, Kyushu University...Transmission Specimen Handling Titanium chemistry...for Electronics and Materials and 2 Art, Science...In a Ti-Al phase diagram, a g-TiAl intermetallic......
Satoshi Hata; Kohjiro Shiraishi; Masaru Itakura; Noriyuki Kuwano; Takayoshi Nakano; Yukichi Umakoshi
Surface Engineering to Improve the Durability and Lubricity of Ti-6Al-4V Alloy
Titanium alloys offer high strength, high corrosion resistance, and the opportunity to reduce the weight of heavy vehicle engine components, but they do not perform well as bearing surfaces without further treatments or coatings. This paper explores a series of surface engineering treatments to improve the friction and wear behavior of Ti-6Al-4V alloy under diesel engine oil-lubricated conditions.
Bansal, Dinesh G [ORNL; Eryilmaz, Osman L [Argonne National Laboratory (ANL); Blau, Peter Julian [ORNL
Microscopic mechanisms of metastable phase formation during ball milling of intermetallic TiAl phases
Powders of the intermetallic equilibrium phases {alpha}{sub 2}-Ti{sub 3}Al, {gamma}-TiAl and TiAl{sub 3} were ball milled in order to investigate the microscopic origins of the energetic destabilization and the transformation into metastable phases during the milling process. It was found that the intermetallic phases were chemically partially disordered on milling followed by the transformation into solid solution phases after long milling. In detail, for the {gamma} phase, the formation of numerous deformation twins, thin h.c.p. lamellae and lamellae of the 9R phase formed by an antitwin operation was observed by TEM. The disordering of the D0{sub 22}-TiAl{sub 3} phase occurred inhomogeneously in the material via the formation of antiphase boundaries on (001) planes, resulting in a f.c.c. solid solution in the final state. In summary, it can be concluded that the formation of the observed metastable phases results from chemical disordering, whereas the excess enthalpy of grain boundaries plays only a minor role for the energetical destabilization of the intermetallic compounds during milling in this case.
Klassen, T.; Oehring, M.; Bormann, R. [GKSS Research Centre, Geesthacht (Germany)] [GKSS Research Centre, Geesthacht (Germany)
Crack initiation and crack growth resistance of Ti-48Al-2Cr sheet material
The present paper reports on the fracture toughness tests conducted on Ti-48Al-2Cr sheet material with near-gamma microstructure produced by hot rolling. Compact tension specimens were sectioned from sheet material and tested at room temperature to determine the fracture toughness and crack growth resistance curves. The deformation and fracture behavior were studied on tested specimens.
Dogan, B.; Schwalbe, K.H. [GKSS Research Centre, Geesthacht (Germany)] [GKSS Research Centre, Geesthacht (Germany); Clemens, H. [Plansee AG, Reutte (Austria)] [Plansee AG, Reutte (Austria)
Deformation and fracture behavior of composite structured Ti-Nb-Al-Co(-Ni) alloys
Tensile ductility of the Ti-based composites, which consist of a ?-Ti phase surrounded by ultrafine structured intermetallics, is tunable through the control of intermetallics. The two Ti-based alloys studied exhibit similar compressive yield strength (about 1000?MPa) and strain (about 35%¢40%) but show a distinct difference in their tensile plasticity. The alloy Ti{sub 71.8}Nb{sub 14.1}Ni{sub 7.4}Al{sub 6.7} fractures at the yield stress while the alloy Ti{sub 71.8}Nb{sub 14.1}Co{sub 7.4}Al{sub 6.7} exhibits about 4.5% of tensile plastic deformation. To clarify the effect of microstructure on the deformation behavior of these alloys, tensile tests were carried out in the scanning electron microscope. It is shown that the distribution as well as the type of intermetallics affects the tensile ductility of the alloys.
Okulov, I. V., E-mail: email@example.com; Marr, T.; Schultz, L.; Eckert, J. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Institut f³r Werkstoffwissenschaft, Technische Universitõt Dresden, D-01062 Dresden (Germany); K³hn, U. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Freudenberger, J. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Institut f³r Werkstoffwissenschaft, Technische Universitõt Bergakademie Freiberg, Gustav-Zeuner-Str. 5, D-09599 Freiberg (Germany); Oertel, C.-G.; Skrotzki, W. [Institut f³r Strukturphysik, Technische Universitõt Dresden, D-01062 Dresden (Germany)
Structural, textural and catalytic properties of Al-, Ti-pillared clays
Al-, Ti- and Zr-pillared clays were characterized and NiMo/Pilc`s were tested in HDS reactions. The combination of activity measurements with Moessbauer Spectroscopy and x-ray microanalysis at microscopical scale give insight in the metal phases migration during pillaring, reaction and regeneration steps. {Alpha}-Fe phase in free Fe{sub 2}O{sub 3} islands predominate together with structural Fe{sup 3+} phase, but during the catalytic reaction Fe{sup 2+} forms. Delamination of the Ti- and Zr-Clay supports, together with high Lewis acidity might enhance their catalytic properties.
Ramos-Galvan, C.E.; Dominguez, J.M.; Sandoval-Robles, G.; Castillo-Mares, A.; Nava E, N.
Thermodynamic properties and stability of AlF-bearing titanite CaTiOSiO4¢CaAlFSiO4
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Calorimetric and experimental data on AlF-bearing titanite are presented that yield thermodynamic properties of CaAlFSiO4, as well as activity-composition relations of binary titanite CaTiOSiO4¢CaAlFSiO4. The hea...
Ulrike Troitzsch; David J. Ellis
Micro-Raman spectroscopic study of nanolaminated Ti{sub 5}Al{sub 2}C{sub 3}
Micro-Raman spectroscopic study and lattice dynamics calculations were conducted to study a recently identified layered ternary carbide, Ti{sub 5}Al{sub 2}C{sub 3}. The experimental Raman shifts were remarkably consistent with the calculated values. Polarized Raman spectrum was collected in the polycrystalline sample, which confirmed the theoretical symmetry assignment of the Raman modes. In addition, the atomic vibrations of the peaks at 192?cm{sup ?1}, 311?cm{sup ?1}, and 660?cm{sup ?1} were identified to be the combination of the counterparts in Ti{sub 2}AlC and Ti{sub 3}AlC{sub 2}.
Zhang, H.; Li, Z. J. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, X. H. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Xiang, H. M.; Zhou, Y. C, E-mail: email@example.com [Science and Technology of Advanced Functional Composite Laboratory, ARIMPT, No.1 South Dahongmen Road, Beijing 100076 (China)
Surface characterization and mechanical property evaluation of thermally oxidized Ti-6Al-4V
The present study concerns development of a thin and adherent oxide film on the surface of Ti-6Al-4V by thermal oxidation. Thermal oxidation was carried out over a range of temperature between 400 to 600 deg. C and a time from 25 h to 60 h. A detailed characterization of the surface and cross section of the oxidized surface was carried out by optical/scanning electron microscopy and X-ray diffraction techniques. Finally, the mechanical properties of the oxidized surface in terms of microindentation hardness and wear resistance were evaluated as a function of oxidation parameters. Surface oxidation of Ti-6Al-4V at 600 deg. C for 36 h offered a defect free oxide scale with improved hardness and wear resistance.
Biswas, Amit [Department of Metal. and Maters. Engg., I. I. T. Kharagpur, W. B. - 721302 (India); Dutta Majumdar, Jyotsna, E-mail: email@example.com [Department of Metal. and Maters. Engg., I. I. T. Kharagpur, W. B. - 721302 (India)
Cold compaction study of Armstrong Process Ti-6Al-4V powders
This work investigates the cold compaction behavior of Ti-6Al-4V powders produced by Armstrong Process . As-received as well as milled powders were characterized and these powders were uniaxially die-pressed at designated pressures up to 690 MPa to form disk samples with different aspect ratios. Samples with high aspect ratio exhibited non-uniform density along the pressing axis and the density distribution is in consistent with the result predicted by finite element analysis. The linear regression analysis on the experimental density data can be used to predict density of compacts with different aspect ratios. In the studied pressure range, an empirical powder compaction equation represents the green density pressure relationship very well for both the as-received and 1-hr milled Armstrong Ti-6Al-4V powders.
Chen, Wei [ORNL; Yamamoto, Yukinori [ORNL; Peter, William H [ORNL; Gorti, Sarma B [ORNL; Sabau, Adrian S [ORNL; Clark, Michael B [ORNL; Nunn, Stephen D [ORNL; Kiggans, Jim [ORNL; Blue, Craig A [ORNL; Fuller, Brian [International Titanium Powder; Akhtar, Kamal [International Titanium Powder
The early stages of solid-state reactions in Ti/Al multilayer films
The authors have investigated the solid-state reaction of Ti/Al multilayer films by x-ray diffraction (XRD) and differential scanning calorimetry (DSC), with focus on the early stages of the reaction provided by samples with pair thicknesses in the range 5--40 nm. This reaction, which results in formation of TiAl{sub 3} with metastable L1{sub 2} structure, can be modeled by a nucleation and growth process on the basis of the Johnson-Mehl-Avrami theory, with a reaction-order parameter n {approx} 1. These observations indicate the significance of nucleation barriers even at early stages of solid-state reactions, and suggests that the phenomena of phase selection and formation of metastable phases can result from the presence of nucleation barriers.
Michaelsen, C.; Woehlert, S.; Bormann, R. [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research; Barmak, K. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science and Engineering
Consolidation Process in Near Net Shape Manufacturing of Armstrong CP-Ti/Ti-6Al-4V Powders
This paper summarizes our recent efforts to develop the manufacturing technologies of consolidated net-shape components by using new low-cost commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy powders made by the Armstrong process. Fabrication processes of net shape/ near net shape components, such as uniaxial die-pressing, cold isostatic pressing (CIP), sintering, roll compaction and stamping, have been evaluated. The press-and-sinter processing of the powders were systematically investigated in terms of theoretical density and microstructure as a function of time, pressure, and temperature. Up to 96.4% theoretical density has been achieved with the press-and-sinter technology. Tensile properties of the consolidated samples exhibit good ductility as well as equivalent yield/ultimate tensile strengths to those of fully consolidate materials, even with the presence of a certain amount of porosity. A consolidation model is also under development to interpret the powder deformation during processing. Net shape components made of the Armstrong powder can successfully be fabricated with clearer surface details by using press-and-sinter processing.
Yamamoto, Yukinori [ORNL; Kiggans, Jim [ORNL; Clark, Michael B [ORNL; Nunn, Stephen D [ORNL; Sabau, Adrian S [ORNL; Peter, William H [ORNL
Synthesis of nanostructured multiphase (Ti,Al)N/a-Si3N4 thin films using dense plasma focus device
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A 2.3ĀkJ pulsed plasma focus device was used to prepare thin films of nc-(Ti,Al)N/a-Si3N4 at room temperature. The plasma focus device, fitted with copper anode encapsulated with Ti0.5Al0.5 anode, was operated with nitrogen as the filling gas. Films were deposited with various number of focus shots, at 90Āmm from top of the anode and at zero angular position with respect to anode axis. XRD patterns show the growth of polycrystalline (Ti,Al)N thin films with orientations in the (1Ā1Ā1), (2Ā0Ā0), (2Ā2Ā0) and (3Ā1Ā1) crystallographic planes. Behavior of lattice constant, grain size and film roughness of deposited film as a function of variation in number of focus shots is discussed. SEM micrographs of film deposited with 15 number of focus shots exhibit well-developed net like structure of nc-(Ti,Al)N/a-Si3N4 and possibly nc-(Ti,Al)N/a-Si3N4/a-AlN or nc-TiN/a-Si3N4/a-AlN. Surface Roughness ranging 64Ānm to 89Ānm was also observed.
Tousif Hussain; R. Ahmad; Nida Khalid; Z.A. Umar; A. Hussnain
Properties of two-phase intermetallic (Ti, Nb){sub 3} (Al, Si) + (Ti, Nb){sub 5} (Si, Al){sub 3} P/M bulk and sheet material
Intermetallic Ti-based alloy powder with nominal composition Ti 23.5Al5.5Si 10 Nb(at.%) was produced by argon gas atomization. This dual phase alloy is composed of the {alpha}{sub 2}-(Ti, Nb){sub 3} (Al,Si)-matrix phase and a eutectic mixture of {alpha}{sub 2}-(Ti, Nb){sub 3}(Al, Si) + {xi}-(Ti, Nb){sub 5} (Si, Al){sub 3}. The powder was compacted by hot isostatic pressing, subsequently hot rolled into sheets, and heat treated. The microstructures of the HIPed compacts and of the sheet materials were metallographically characterized and correlated with tensile properties at temperatures between 20 and 1,000 C. Due to networks of the brittle {xi}-silicide phase, the HIPed state showed no ductility at 20 C. Break-down of the silicide network during rolling led to an improved ductility at 20 C. After post rolling annealing, the yield strengths at 20 and 700 C were between 750--490 MPa and 700--420 MPa for specimens taken parallel and perpendicular to the rolling direction, respectively. These values are considerably higher than those reported for {gamma}-TiAl sheets. At 1,000 C the sheet material could be superplastically deformed.
Gerling, R.; Oehring, M.; Schimansky, F.P. [GKSS-Forschungszentrum, Geesthacht (Germany)] [GKSS-Forschungszentrum, Geesthacht (Germany); Bartels, A. [TU Hamburg-Harburg (Germany)] [TU Hamburg-Harburg (Germany); Clemens, H. [Plansee Aktiengesellschaft, Reutte (Austria). Technology Center] [Plansee Aktiengesellschaft, Reutte (Austria). Technology Center
Composition, morphology and mechanical properties of sputtered TiAlN coating
TiAlN coating was deposited on the tungsten carbide cutting tool by using DC magnetron sputtering system to study the influence of substrate bias and nitrogen flow rate on the composition, morphology and mechanical properties. The negatively substrate bias and nitrogen flow rate was varied from about ?79 to ?221 V and 30 sccm to 72 sccm, respectively. The coating composition and roughness were characterized by using SEM/EDX and Atomic Force Microscopy (AFM), respectively. The dynamic ultra micro hardness tester was used to measure the mechanical properties. The coating hardness increases to about 10-12 GPa with an increase of the negatively substrate bias up to ? 200 V and it tend to decrease with an increase in nitrogen flow rate up to 70 sccm. The increase of hardness follows the increase of Ti and N content and rms coating roughness.
Budi, Esmar, E-mail: firstname.lastname@example.com [Department of Physics, Faculty of Science and Mathematics, Universitas Negeri Jakarta, Jl. Pemuda No. 10, Jakarta 13220 (Indonesia); Razali, M. Mohd. [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Karung Berkunci No. 1752 Pejabat Pos Durian Tunggal 76109 Melaka (Malaysia); Nizam, A. R. Md. [Faculty of Manufacturing Engineering, UniversitiTeknikal Malaysia Melaka, Karung Berkunci No. 1752 Pejabat Pos Durian Tunggal 76109 Melaka (Malaysia)
Effect of aluminum content on synthesis of Ti2AlC and Ti3AlC2 during treatment in a high-energy mill and hot pressing
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Treatment of initial powders of titanium, carbon and aluminum in a high-energy mill and pressure sintering are used for...2AlC and Ti3AlC2 ceramics. The effect of the content of aluminum and of the sintering temp...
Jianfeng Zhu; Guoquan Qi; Fen Wang; Haibo Yang; Ying Li
Effects of processing on texture, microstructure and related properties of TiAl alloys
Depending on factors such as processing conditions, stoichiometry and initial microstructure a variety of different textures has been found in TiAl alloys. They give insight into the origin of the generation of preferred orientations during solidification and recrystallization and by rotation of orientations during deformation. A comparison of measured and simulated textures on the basis of current models of polycrystal deformation leads to general conclusions about the crystallography of slip and on the strength of the different slip systems. The knowledge of texture is profitable for an understanding as well as for an explanation of the anisotropy of mechanical properties such as elastic constants, plastic behavior and fracture parameters.
Mecking, H.; Hartig, C. [Technical Univ. Hamburg-Harburg, Hamburg (Germany)
Time-dependent stress concentration and microcrack nucleation in TiAl
Localized stress evolution associated with the interaction of slip or twinning with an interface is treated by means of a superposition of the internal loading of a crystalline subsystem by dynamic dislocation pile-up and the stress relaxation by climb of interfacial dislocations. The peak value of a stress concentration factor depends on both the angular function that includes the effect of mode mixity and the ratio of characteristic times for stress relaxation and internal loading. The available experimental data on orientation and strain rate dependences of interfacial fracture mode in polysynthetically twinned TiAl crystals are discussed in view of the theoretical concepts presented in this paper.
Yoo, M.H. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Division
Improved Hydrogen Storage Kinetics of Nanoconfined NaAlH4 Catalyzed with TiCl3 Nanoparticles
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Improved Hydrogen Storage Kinetics of Nanoconfined NaAlH4 Catalyzed with TiCl3 Nanoparticles ... We demonstrate that NaAlH4 confined within the nanopores of a titanium-functionalized metal¢organic framework (MOF) template MOF-74(Mg) can reversibly store hydrogen with minimal loss of capacity. ...
Thomas K. Nielsen; Marek Polanski; Dariusz Zasada; Payam Javadian; Flemming Besenbacher; Jerzy Bystrzycki; J°rgen Skibsted; Torben R. Jensen
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
71 IA Blog Archive en IA News Archive http:energy.goviaia-news-archive IA News Archive
High-Temperature Galling Characteristics of Ti-6Al-4V with and without Surface Treatments
Galling is a severe form of surface damage in metals and alloys that typically arises under relatively high normal force, low-sliding speed, and in the absence of effective lubrication. It can lead to macroscopic surface roughening and seizure. The occurrence of galling can be especially problematic in high-temperature applications like diesel engine exhaust gas recirculation system components and adjustable turbocharger vanes, because suitable lubricants may not be available, moisture desorption promotes increased adhesion, and the yield strength of metals decreases with temperature. Oxidation can counteract these effects to some extent by forming lubricative oxide films. Two methods to improve the galling resistance of titanium alloy Ti-6Al-4V were investigated: (a) applying an oxygen diffusion treatment, and (b) creating a metal-matrix composite with TiB2 using a high-intensity infrared heating source. A new, oscillating three-pin-on-flat, high-temperature test method was developed and used to characterize galling behavior relative to a cobalt-based alloy (Stellite 6B ). The magnitude of the oscillating torque, the surface roughness, and observations of surface damage were used as measures of galling resistance. Owing to the formation of lubricative oxide films, the galling resistance of the Ti-alloy at 485o C, even non-treated, was considerably better than it was at room temperature. The IR-formed composite displayed reduced surface damage and lower torque than the substrate titanium alloy.
Blau, Peter Julian [ORNL; ERDMAN III, DONALD L [ORNL; Ohriner, Evan Keith [ORNL; Jolly, Brian C [ORNL
A transmission electron microscopy study of the deformation behavior underneath nanoindents in nano-scale Al-TiN multilayered composites
Nano-scale multilayered Al-TiN composites were deposited with DC magnetron sputtering technique in two different layer thickness ratios - Al:TiN = 1:1 and Al:TiN = 9:1. The Al layer thickness varied from 2 nm to 450 nm. The hardness of the samples was tested by nanoindentation using a Berkovich tip. Cross-sectional Transmission Electron Microscopy (TEM) was carried out on samples extracted with Focused Ion Beam (FIB) from below the nanoindents. This paper presents the results of the hardness tests in the Al-TiN multilayers with the two different thickness ratios and the observations from the cross-sectional TEM studies of the regions underneath the indents. These studies showed remarkable strength in the multilayers, as well as some very interesting deformation behavior in the TiN layers at extremely small length scales, where the hard TiN layers undergo co-deformation with the Al layers.
Bhattacharyya, Dhriti [Los Alamos National Laboratory; Mara, Nathan A [Los Alamos National Laboratory; Dickerson, Patricia O [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Hoagland, R G [Los Alamos National Laboratory
Investigating surface roughness, material removal rate and corrosion resistance in PMEDM of ?-TiAl intermetallic
Science Journals Connector (OSTI)
Titanium aluminide intermetallics offer an attractive combination of low density and good oxidation, corrosion and ignition resistance with unique mechanical properties. In this study two series of machining tests are designed. Firstly the powder mixed electrical discharge machining (PMEDM) of ?-TiAl by means of different powders such as aluminum, chrome, silicon carbide, graphite and iron is performed to investigate the output characteristics of surface roughness and topography, material removal rate (MRR), electrochemical corrosion resistance of machined samples and also the machined surfaces are investigated by means of EDS and XRD analyses. Secondly after selection the aluminum powder as the most appropriate kind of powder, the current, pulse on time, powder size and powder concentration are changed in different levels for overall comparison between EDM and PMEDM output characteristics. In the first setting of input machining parameters, aluminum powder improves the surface roughness of TiAl sample about 32% comparing with EDM case and also aluminum particles with the size of 2Ā?m, in the second setting of input parameters lead to 54% enhancement of MRR comparing with EDM case. The electrochemical corrosion results show that, corrosion resistance of the samples which are machined by graphite and chrome powders respectively are about three and two times more than the sample which is machined without powder.
Behzad Jabbaripour; Mohammad Hossein Sadeghi; Mohammad Reza Shabgard; Hossein Faraji
Analysis of defect generation in Ti¢6Al¢4V parts made using powder bed fusion additive manufacturing processes
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Abstract Ti¢6Al¢4V parts made using additive manufacturing processes such as selective laser melting (SLM) and electron beam melting (EBM) are subject to the inclusion of defects. This study purposely fabricated Ti¢6Al¢4V samples with defects by varying process parameters from the factory default settings in both SLM and EBM systems. Process parameters are classified according to their tendency to create certain types of porosity. Finally, defect characteristics are discussed with respect to defect generation mechanisms; and effective process windows for SLM and EBM system are discussed.
Haijun Gong; Khalid Rafi; Hengfeng Gu; Thomas Starr; Brent Stucker
Laser cladding Al-Si/Al2O3-TiO2 composite coatings on AZ31B magnesium alloy
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To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31B magnesium alloys with Al-Si/...2O3 -TiO2.....
Zeqin Cui ???; Hongwei Yangģ
The investigation of die-pressing and sintering behavior of ITP CP-Ti and Ti-6Al-4V powders
This paper investigated the die-pressing and sintering behavior of the low-cost CP-Ti and Ti-6Al- 4V powders made by the Armstrong Process . The Armstrong powders have an irregular coral like, dendritic morphology, with a dendrite size of approximately 2-5 m. As-received as well as milled powders were uniaxially pressed at designated pressures up to 690 MPa to form disk samples with different aspect ratios. In the studied pressure range, an empirical powder compaction equation was applied to linearize the green density pressure relationship, and powder compaction parameters were obtained. The Armstrong Ti-64 powder exhibited a significantly higher sinterability than the CP-Ti powder. This was explained to be due to the higher diffusivity of V at the sintering temperature. The Ti-64 samples with a green density of 71.0% increased to 99.6% after sintering at 1300oC for 1 hour. An ex-situ technique was used to track the powder morphology change before and after sintering.
Chen, Wei [ORNL; Yamamoto, Yukinori [ORNL; Peter, William H [ORNL; Clark, Michael B [ORNL; Nunn, Stephen D [ORNL; Kiggans, Jim [ORNL; Muth, Thomas R [ORNL; Blue, Craig A [ORNL; Williams, James C [Ohio State University; Fuller, Brian [International Titanium Powder; Akhtar, Kamal [International Titanium Powder
Statistical simulation of small fatigue crack nucleation and coalescence in a lamellar TiAl alloy
This article examines the possibility of fatigue failure as the result of fatigue crack nucleation and coalescence at stress ranges below the fatigue limit and the large crack threshold where fatigue cracks are expected not to grow. By representing the material as a two-dimensional array of beam elements, the nucleation of nonpropagating small cracks at various material locations is modeled via a statistical approach that considers fatigue crack nucleation by accumulation of damage at randomly distributed weak regions. Once nucleated, the fatigue cracks do not propagate but extend only by linking with fatigue cracks subsequently formed in the contiguous elements. Result of the computer simulation suggests that fatigue failure by crack nucleation and coalescence is feasible, but the cycles-to-coalescence is much longer than the cycles-to-initiation for the first crack. Implications of the results in fatigue life assessment based on the Kitagawa diagram are discussed for TiAl alloys.
Chan, K.S. [Southwest Research Inst., San Antonio, TX (United States); Wittowsky, B. [Proctor and Gamble European Service GmbH, Euskirchen (Germany); Pfuff, M. [GKSS Research Center, Geesthacht (Germany)
Elastic properties of low density core (LDC) Ti-6Al-4V sandwich cores
Lightweight, structurally efficient low density core (LDC) sandwich structures can be produced by entrapping argon gas within a finely dispersed distribution of pores in a microstructure and using a high temperature anneal to cause pore growth by gas expansion. This results in a porous microstructure with a relative density as low as {approximately}0.70. Laser ultrasonic methods have been used to measure the longitudinal and shear wave velocities and hence the elastic properties of LDC Ti-6Al-4V cores prior to, and after gas expansion treatments of up to 48 hr at 920 C. The data were compared with several analytical models for predicting the volume fraction of porosity dependent elastic properties of porous materials.
Queheillalt, D.T.; Wadley, H.N.G. [Univ. of Virginia, Charlottesville, VA (United States). IPM Lab.; Schwartz, D.S. [Boeing Co., St. Louis, MO (United States)
Upper critical field of Ti and ?-TiAl alloys: Evidence of an intrinsic type-II superconductivity in pure Ti
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The upper critical field Hc2 of ?-Ti1-xAlx(0Fermi velocity obtained here is substantially lower than predicted by band calculation. The present work gives clear evidence that pure Ti is an intrinsic type-II superconducting element due to its very low renormalized Fermi velocity.
Liu Shumei; Zhang Dianlin; Jing Xiunian; Lu Li; Li Shanlin; Kang Ning; Wu Xiaosong; J. J. Lin
Development and Characterization of Hard and Wear Resistant MMC Coating on Ti-6Al-4V Substrate by Laser Cladding
Science Journals Connector (OSTI)
Abstract Ti-6Al-4V, due to its high specific strength and resistance to corrosion, is one of the highly useful materials in aerospace, automobile and chemical industries. Poor hardness and wear resistance properties restrict its further applications. So surface modification of Ti-6Al-4V is necessary surface to enhance its tribological properties. Multi-phase and multi component coating development is one of the present research trends in surface engineering arena. In the present study it was attempted to develop a multi-component coating by laser cladding process using a pre-placed powder mixture containing Ni5Al (50 vol%) + hBN (10 vol%) + B4C (20 vol%) + SiC (20 vol%) on substrate of Ti-6Al-4V to improve its tribological performance. A nano-structured coating was formed with micro hardness (780 HV0.05). X-ray diffraction (XRD) identified the presence of compounds like TiC, BN, TiB2, SiC, and intermetallics of Ni-Ti in the coating. The wear behaviour of the composite coating was assessed by ball on disc type wear and friction monitor at 10ĀN load at 300 RPM taking a track diameter of 5Āmm. Specific wear rate and coefficient of friction (?) were found to vary from 0.6E-12 to 2.2E-12 m3/N-m and from 0.15 to 0.45, respectively, due to rubbing of coated surface against tungsten carbide ball. The microstructure was explored by Scanning Electron Microscopy (SEM).
Mandeep Dhanda; Barun Haldar; P. Saha
Long period structures in Ti1+xAl3-x alloys : experimental evidence of a devil's staircase ?
595 Long period structures in Ti1+xAl3-x alloys : experimental evidence of a devil's staircase ? A of a so-called devil's staircase. The experimental results are compared with those obtained in Ag3Mg domain size M depends on temperature; this dependence corresponds to a simple (harmless) staircase below
Boyer, Edmond
Electronic and atomic structures of Ti{sub 1-x}Al{sub x}N thin films related to their damage behavior
Ti and Al K-edge x-ray absorption spectroscopy is used to investigate the electronic structure of Ti{sub 1-x}Al{sub x}N thin films deposited by reactive magnetron sputtering. The experimental near edge spectra of TiN and AlN are interpreted in the light of unoccupied density of state band structure calculations. The comparison of the structural parameters derived from x-ray absorption fine structure and x-ray diffraction reveals segregation between Al-rich and Ti-rich domains within the Ti{sub 1-x}Al{sub x}N films. Whereas x-ray diffraction probes only the crystallized domains, the structural information derived from extended x-ray absorption fine structure analysis turns on both crystalline and grain boundaries. The results are discussed by considering the damage behavior of the films depending on the composition.
Tuilier, M.-H.; Pac, M.-J.; Girleanu, M.; Covarel, G.; Arnold, G.; Louis, P. [Laboratoire de Mecanique, Materiaux et Procedes de Fabrication, Universite de Haute Alsace, 61 rue Albert Camus, F-68093 Mulhouse cedex (France); Rousselot, C. [Institut FEMTO-ST (UMR CNRS 6174), Universite de Franche-Comte, BP 71427, F-25211 Montbeliard cedex (France); Flank, A.-M. [CNRS--UR1 SOLEIL, F-91192 Gif sur Yvette cedex (France)
X-ray diffraction line profile analysis of deformation microstructure in boron modified Ti-6Al-4V alloy
X-ray diffraction line profile analysis (XRDLPA) techniques have been applied to investigate the deformed microstructure of a recently developed boron modified two-phase titanium alloy Ti-6Al-4V. The alloy was hot compressed at 750 deg. C up to 50% height reduction at two different strain rates (10{sup -3} S{sup -1} and 1 S{sup -1}). Microstructural parameters like average domain size, average microstrain within the domain and dislocation density of the two phases were determined using X-ray diffraction line profile analysis. The results indicate an increase in the microstrain and dislocation density for the {alpha}-phase and decrease for the {beta}-phase in the case of boron modified alloys as compared to the normal material. Microstructural modifications viz. the grain refinement and the presence of hard, brittle TiB particles in the case of boron modified alloy are held responsible for the observed difference in the dislocation density. - Research Highlights: {yields} Microstructural examination of hot compressed Ti64 with and without boron addition by XRDLPA. {yields} Smaller average domain size in alpha-phase compared to the corresponding alpha-phase in all cases. {yields} Higher microstrain and dislocation density for {alpha} phase and lower for {beta} phase in case of Ti64+B. {yields} Decrease in domain size while increase in micro-strain and dislocation density with strain rate. {yields} Strain accumulation around TiB particles responsible for high dislocation density in {alpha} phase.
Sarkar, Apu; Roy, Shibayan; Suwas, Satyam, E-mail: firstname.lastname@example.com
Silicide precipitation in a {gamma}-based Ti-47Al-2W-0.5Si alloy
Although some work on microstructure of silicides in {gamma}-TiAl alloys has been done, it is restricted to the alloys containing high content of silicon ({approximately}3at.%). Furthermore, to the authors` knowledge, the crystal orientation relation between silicide and {beta} matrix that is stabilized to room temperature in the alloys containing transition elements (such as Nb, V, W, Cr), has not been reported yet. The present investigation was undertaken /to study the silicides in a {gamma}-TiAl base alloy with 2 at.% W addition containing 0.28--0.59 at.% Si after different heat treatments, to understand the effects of silicon content and heat treatment on the formation and morphology of silicides.
Yin, W.M. [CNR-ITM, Cinisello Balsamo (Italy)] [CNR-ITM, Cinisello Balsamo (Italy); [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research; Lupinc, V. [CNR-ITM, Cinisello Balsamo (Italy)] [CNR-ITM, Cinisello Balsamo (Italy)
In-situ sensing of the expansion of low density core (LDC) Ti-6Al-4V sandwich structures
A combination multifrequency eddy current and laser ultrasonic sensors have been used to measure the pore expansion kinetics and elastic moduli evolution during the annealing of low density core (LDC) Ti-6Al-4V sandwich structures. The LDC samples were heated to 920 C and held there for up to 12 hr. The eddy current sensor measured the sample thickness (i.e., relative density) and revealed that the samples began to expand early during heating and was nearly complete after 4 hr at 920 C. The laser ultrasonic sensor measurements indicated a concomitant decrease in the elastic moduli with the reduction in relative density. The combination of an eddy current and laser ultrasonic sensor is therefore able to measure both the density and the elastic moduli independently during the annealing stage of LDC Ti-6Al-4V sandwich structure processing providing a simple method for directly controlling the parameters most critical to aerospace applications of these new materials.
Queheillalt, D.T.; Choi, B.W.; Wadley, H.N.G. [Univ of Virginia, Charlottesville, VA (United States). IPM Lab.; Schwartz, D.S. [Boeing Co., St. Louis, MO (United States)
Fabricating superconducting interfaces between artificially grown LaAlO{sub 3} and SrTiO{sub 3} thin films
Realization of a fully metallic two-dimensional electron gas (2DEG) at the interface between artificially grown LaAlO{sub 3} and SrTiO{sub 3} thin films has been an exciting challenge. Here we present for the first time the successful realization of a superconducting 2DEG at interfaces between artificially grown LaAlO{sub 3} and SrTiO{sub 3} thin films. Our results highlight the importance of two factorsŚthe growth temperature and the SrTiO{sub 3} termination. We use local friction force microscopy and transport measurements to determine that in normal growth conditions the absence of a robust metallic state at low temperature in the artificially grown LaAlO{sub 3}/SrTiO{sub 3} interface is due to the nanoscale SrO segregation occurring on the SrTiO{sub 3} film surface during the growth and the associated defects in the SrTiO{sub 3} film. By adopting an extremely high SrTiO{sub 3} growth temperature, we demonstrate a way to realize metallic, down to the lowest temperature, and superconducting 2DEG at interfaces between LaAlO{sub 3} layers and artificially grown SrTiO{sub 3} thin films. This study paves the way to the realization of functional LaAlO{sub 3}/SrTiO{sub 3} superlattices and/or artificial LaAlO{sub 3}/SrTiO{sub 3} interfaces on other substrates.
Li, Danfeng, E-mail: firstname.lastname@example.com; Gariglio, Stefano; Cancellieri, Claudia; FĻte, Alexandre; Stornaiuolo, Daniela; Triscone, Jean-Marc [DPMC, University of Geneva, 24 Quai Ernest Ansermet, 1211 Geneva (Switzerland)
Influence of Microstructure on High-Cycle Fatigue of Ti-6Al-4V: Bimodal vs. Lamellar Structures
for such failures in Ti-6Al-4V, a commonly used turbine blade alloy, specifically for fan and compressor blades.K. NALLA, B.L. BOYCE, J.P. CAMPBELL, J.O. PETERS, and R.O. RITCHIE The high-cycle fatigue (HCF) of titanium] HCF can result in essentially unpredictable used for blade and disk applications in the front (low
Ritchie, Robert
INVESTIGATION OF NOVEL ALLOY TiC-Ni-Ni3Al FOR SOLID OXIDE FUEL CELL INTERCONNECT APPLICATIONS
Solid oxide fuel cell interconnect materials must meet stringent requirements. Such interconnects must operate at temperatures approaching 800 C while resisting oxidation and reduction, which can occur from the anode and cathode materials and the operating environment. They also must retain their electrical conductivity under these conditions and possess compatible coefficients of thermal expansion as the anode and cathode. Results are presented in this report for fuel cell interconnect candidate materials currently under investigation based upon nano-size titanium carbide (TiC) powders. The TiC is liquid phase sintered with either nickel (Ni) or nickel-aluminide (Ni{sub 3}Al) in varying concentrations. The oxidation resistance of the submicron grain TiC-metal materials is presented as a function weight change versus time at 700 C and 800 C for varying content of metal/intermetallic in the system. Electrical conductivity at 800 C as a function of time is also presented for TiC-Ni to demonstrate the vitality of these materials for interconnect applications. TGA studies showed that the weight gain was 0.8 mg/cm{sup 2} for TiC(30)-Ni(30wt.%) after 100 hours in wet air at 800 C and the weight gain was calculated to be 0.5205 mg/cm{sup 2} for TiC(30)- Ni(10 wt.%) after 100 hours at 700 C and 100 hours at 800 C. At room temperature the electrical conductivity was measured to be 2444 1/[ohm.cm] for TiC-Ni compositions. The electrical conductivities at 800 C in air was recorded to be 19 1/[ohm.cm] after 125 hours. Two identical samples were supplied to PNNL (Dr. Jeff Stevenson) for ASR testing during the pre-decision period and currently they are being tested there. Fabrication, oxidation resistance and electrical conductivity studies indicate that TiC-Ni-Ni{sub 3}Al ternary appears to be a very important system for the development of interconnect composition for solid oxide fuel cells.
Rasit Koc; Geoffrey Swift; Hua Xie
Statistical evaluation of potential damage to the Al(OH)3 layer on nTiO2 particles in the presence of swimming pool and seawater
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Nanosized TiO2 particles (nTiO2) are usually coated with an Al(OH)3 layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles are exposed to UV r...
Jurate Virkutyte; Souhail R. Al-Abed
Investment casting of {gamma}-TiAl-based alloys: Microstructure and data base for gas turbine applications
Investment casting is regarded as an economic processing technology for the production of {gamma}-TiAl based components for gas turbine applications. Near net-shape parts can be cast such that they are free from pores and flaws after adequate `HIP`ping. The inhomogeneous cast microstructure which results from locally varying cooling rates (e.g. in the root and foil of a blade), however, is often retained even after heat-treatments necessary to achieve a balance of properties for a given application. Appropriate modifications of the alloy chemistry may lead to an improved microstructural homogeneity in the cast parts. Data bases of properties (tensile properties, creep, fatigue and rupture strength, fracture and impact toughness, oxidation and corrosion resistance) which are relevant for potential gas turbine applications have been assessed for different cast {gamma}-TiAl alloys with different microstructures. These are compared with corresponding properties of nickel-based and iron-based superalloys {gamma}-TiAl is competing with for substitution.
Wagner, R.; Appel, F.; Dogan, B. [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research] [and others
An Investigation into the evolution of damage and residual stresses in Ti6Al4V-Al?Ti metal intermetallic laminate (MIL) composites
good creep resistance, and relatively low material density.strengthened materials are toughened since the resistance toresistance of interfaces in NiAl/Mo model laminates, Materials
Li, Tiezheng
Characterization of Ti diffusion in PVD deposited WTi/AlCu metallization on monocrystalline Si by means of secondary ion mass spectroscopy
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The diffusion behavior of Titanium in Al0.5Cu/W18Ti (at.%) metallization stacks on monocrystalline Silicon has been investigated. The metallization system was prepared by in situ sputtering deposition. It is demonstrated that \\{WTi\\} is not stable as a diffusion barrier between Al0.5Cu and Si in temperature ranges between 623ĀK and 673ĀK due to Ti depletion. The Ti diffusion in Al0.5Cu is characterized by diffusion profiles prepared by secondary ion mass spectroscopy after annealing. The activation energy derived from this data is 2.28ĀeV for Ti diffusion into Al0.5Cu. The causal chain of detecting this behavior is described application-oriented.
M. Plappert; O. Humbel; A. Koprowski; M. Nowottnick
Inuence of foreign-object damage on crack initiation and early crack growth during high-cycle fatigue of Ti6Al4V
; Ti┬▒6Al┬▒4V 1. Introduction The high-cycle fatigue (HCF) of aircraft gas-turbine engine components has of small surface fatigue cracks in a Ti┬▒6Al┬▒4V alloy, processed for typical turbine blade applications microcracks in the damaged zone (seen only at the higher impact velocities). Furthermore, the eect of residual
Ritchie, Robert
Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
+ 2AlH 3 3 NaAlH 4 M. Mamula et al., Coll. Czechoslov. Chem. Commun. 32, 884 (1967). Atomic Hydrogen Interacting with Al Surfaces "H adsorption and the formation of alane...
On the preparation of TiAl alloy by direct reduction of the oxide mixtures in calcium chloride melt
In recent years, TiAl-based intermetallic alloys are being increasingly considered for application in areas such as (i) automobile/transport sector (passenger cars, trucks and ships) (ii) aerospace industry (jet engines and High Speed Civil Transport propulsion system) and (iii) industrial gas turbines. These materials offer excellent (i) high temperature properties (at higher than 6000C) (ii) mechanical strength and (iii) resistance to corrosion and as a result have raised renewed interest. The combination of these properties make them possible replacement materials for traditional nickel-based super-alloys, which are nearly as twice as dense (than TiAl based alloys). Since the microstructures of these intermetallic alloys affect, to a significant extent, their ultimate performance, further improvements (by way of alteration/modification of these microstructures), have been the subject matter of intense research investigations. It has now been established that the presence of alloy additives, such as niobium, tantalum, manganese, boron, chromium, silicon, nickel and yttrium etc, in specific quantities, impart marked improvement to the properties, viz. fatigue strength, fracture toughness, oxidation resistance and room temperature ductility, of these alloys. From a number of possible alloy compositions, {gamma}-TiAl and Ti-Al-Nb-Cr have, of late, emerged as two promising engineering alloys/materials. . The conventional fabrication process of these alloys include steps such as melting, forging and heat treatment/annealing of the alloy compositions. However, an electrochemical process offers an attractive proposition to prepare these alloys, directly from the mixture of the respective oxides, in just one step. The experimental approach, in this new process, was, therefore, to try to electrochemically reduce the (mixed) oxide pellet to an alloy phase. The removal of oxygen, from the (mixed) oxide pellet, was effected by polarizing the oxide pellet against a graphite electrode in a pool of molten calcium chloride at a temperature of 9000C. The dominant mechanism of the oxygen removal was the ionization of oxygen followed by its subsequent discharge, as CO2/CO, at the anode surface. The removal of oxygen from the oxide mixture helped form the alloy in situ. The presentation shall cover the detailed experimental results pertaining to the preparation, evaluation and characterization of Ti-47Al-2Nb-2Cr (atom%) alloy.
Prabhat K. Tripathy; Derek J. Fray
Substrate orientation effects on the nucleation and growth of the M{sub n+1}AX{sub n} phase Ti{sub 2}AlC
The M{sub n+1}AX{sub n} (MAX) phases are ternary compounds comprising alternating layers of a transition metal carbide or nitride and a third ''A-group'' element. The effect of substrate orientation on the growth of Ti{sub 2}AlC MAX phase films was investigated by studying pulsed cathodic arc deposited samples grown on sapphire cut along the (0001), (1010), and (1102) crystallographic planes. Characterization of these samples was by x-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. On the (1010) substrate, tilted (1018) growth of Ti{sub 2}AlC was found, such that the TiC octahedra of the MAX phase structure have the same orientation as a spontaneously formed epitaxial TiC sublayer, preserving the typical TiC-Ti{sub 2}AlC epitaxial relationship and confirming the importance of this relationship in determining MAX phase film orientation. An additional component of Ti{sub 2}AlC with tilted fiber texture was observed in this sample; tilted fiber texture, or axiotaxy, has not previously been seen in MAX phase films.
Tucker, Mark D.; Guenette, Mathew C.; Bilek, Marcela M. M.; McKenzie, David R. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Persson, Per O. A.; Rosen, Johanna [School of Physics, University of Sydney, New South Wales 2006 (Australia); Thin Film Physics, Linkoepings Universitet, 58183 Linkoeping (Sweden)
E-Print Network 3.0 - al si ti Sample Search Results
NLE Websites -- All DOE Office Websites (Extended Search)
and SiC. Internal grains of SiC and kamaciteiron silicide are also found independent of TiC. The grain... by volume. V and Si were also present in ... Source: Washington...
Conducting and insulating LaAlO{sub 3}/SrTiO{sub 3} interfaces: A comparative surface photovoltage investigation
Surface photovoltage (SPV) spectroscopy, which is a versatile method to analyze the energetic distribution of electronic defect states at surfaces and interfaces of wide-bandgap semiconductor (hetero-)structures, is applied to comparatively investigate heterostructures made of 5-unit-cell-thick LaAlO{sub 3} films grown either on TiO{sub 2}- or on SrO-terminated SrTiO{sub 3}. As shown in a number of experimental and theoretical investigations in the past, these two interfaces exhibit dramatically different properties with the first being conducting and the second insulating. Our present SPV investigation reveals clearly distinguishable interface defect state distributions for both configurations when interpreted within the framework of a classical semiconductor band scheme. Furthermore, bare SrTiO{sub 3} crystals with TiO{sub 2} or mixed SrO/TiO{sub 2} terminations show similar SPV spectra and transients as do LaAlO{sub 3}-covered samples with the respective termination of the SrTiO{sub 3} substrate. This is in accordance with a number of recent works that stress the decisive role of SrTiO{sub 3} and the minor role of LaAlO{sub 3} with respect to the electronic interface properties.
Beyreuther, E., E-mail: email@example.com; Thiessen, A.; Grafstr÷m, S.; Eng, L. M. [Institut f³r Angewandte Photophysik, Technische Universitõt Dresden, D-01062 Dresden (Germany); Paparo, D. [CNR-SPIN and Dipartimento di Fisica, UniversitÓ di Napoli ōFederico II,ö Compl. Univ. di Monte S. Angelo, via Cintia, I-80126 Napoli (Italy)
Dissimilar-alloy laser welding of titanium: Ti6Al-4V to Beta-C{trademark}
Beta-C{sup TM} is a metastable-beta titanium alloy (nominal composition: Ti-3wt%Al-8wt%V-6wtTCr-4wt%Mo-4wt%Zr) which can be thermomechanically processed and heat treated to provide excellent combinations of strength, ductility, and fracture toughness. Recently, the increased application of metastable-beta titanium alloys in aerospace and commercial applications has resulted in the necessity to join these alloys to conventional alpha-beta titanium alloys. Based on this previous work, two approaches were considered for improving the ductility of dissimilar-alloy welds between Ti-6Al-4V and Beta-C{sup TM} in the present study: (1) application of a low heat input welding process to minimize the fusion zone and heat-affected zone (HAZ) beta grain size and (2) modification of the fusion zone chemical composition to allow greater microstructural optimization through postweld aging. CO{sub 2} laser welds were produced between Ti-6Al-4V and Beta-C{sup TM} sheet. Three different nominal fusion zone chemical compositions were obtained by varying the laser beam locations relative to the joint centerline and thereby melting different quantities of each base metal. For comparable postweld aging conditions, the laser welds exhibited ductilities superior to those of coarse-grained gas tungsten arc welds. Fracture analysis of the weld zone revealed a transition from a predominantly transgranular fracture in the low-temperature aged conditions to increasingly intergranular fracture following aging at higher temperature. This transition was promoted by an increase in the thickness and continuity of alpha phase at beta grain boundaries.
Liu, P.S.; Baeslack, W.A. III; Hurley, J.
Comparison of \\{WTi\\} and WTi(N) as diffusion barriers for Al and Cu metallization on Si with respect to thermal stability and diffusion behavior of Ti
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Abstract The thermal stability of \\{WTi\\} and WTi(N) as diffusion barriers for Al and Cu metallization on Si (1Ā0Ā0) was investigated by time of flight secondary ion mass spectrometry (ToF-SIMS) depth profiling, X-ray diffraction (XRD), electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). For both, Al and Cu, Ti diffusion out of \\{WTi\\} into the metal was proved to occur at elevated temperatures (400Ā░C for Al and 600Ā░C for Cu) which further results in barrier film failure. Nitrogen incorporation into \\{WTi\\} leads to an elimination of the Ti diffusion and consequently to a better thermal stability of the barrier film. It is shown that besides crystal structure, Ti diffusion into the metallization is an essential factor of the barrier failure mechanism. The failure temperature for Al is lower than for Cu.
M. Fugger; M. Plappert; C. Schõffer; O. Humbel; H. Hutter; H. Danninger; M. Nowottnick
Electrospark deposition of Al2O3¢TiB2/Ni composite-phase surface coatings on Cu¢Cr¢Zr alloy electrodes
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Abstract To improve electrode life during the resistance spot welding of galvanized steel plates, an Al2O3¢TiB2 composite coating was synthesized on the surfaces of spot-welding electrodes through an electrospark deposition process. The microstructure, elemental composition, phase structure, and mechanical properties of the coating were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and microhardness testing. It was found that extensive cracking occurred in the monolithic Al2O3¢TiB2 coating and at the coating¢electrode interface. When the Al2O3¢TiB2 coating was deposited on electrodes precoated with Ni, the number of defects decreased significantly. Further, delamination did not occur, and fewer cracks were formed. The average hardness of the multilayered Al2O3¢TiB2/Ni coating was approximately 2200ĀHV and higher than that of the monolithic Al2O3¢TiB2 coating (1100ĀHV).
Ping Luo; Shijie Dong; Anzhuo Yangli; Shixuan Sun; Zhong Zheng; Huihu Wang
Octahedral rotations in strained LaAlO{sub 3}/SrTiO{sub 3} (001) heterostructures
Many complex oxides display an array of structural instabilities often tied to altered electronic behavior. For oxide heterostructures, several different interfacial effects can dramatically change the nature of these instabilities. Here, we investigate LaAlO{sub 3}/SrTiO{sub 3} (001) heterostructures using synchrotron x-ray scattering. We find that when cooling from high temperature, LaAlO{sub 3} transforms from the Pm3{sup »}m to the Imma phase due to strain. Furthermore, the first 4 unit cells of the film adjacent to the substrate exhibit a gradient in rotation angle that can couple with polar displacements in films thinner than that necessary for 2D electron gas formation.
Fister, T. T.; Hruszkewycz, S. O.; Proffit, D. L.; Eastman, J. A.; Fuoss, P. H.; Baldo, P. M.; Fong, D. D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Zhou, H. [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Luo, Z. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Seo, S. S. A.; Lee, H. N. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
Modulation of conductance and superconductivity by top-gating in LaAlO{sub 3}/SrTiO{sub 3} 2-dimensional electron systems
We report the electrical top-gating of a 2-dimensional electron gas (2DEG) formed at the LaAlO{sub 3}/SrTiO{sub 3} interface, using electron-beam evaporated Au gate electrodes. In these structures, epitaxial LaAlO{sub 3} films grown by pulsed laser deposition induce the 2DEGs at the interface to the SrTiO{sub 3} substrate and simultaneously act as the gate dielectric. The structured top-gates enable a local tuning and complete on/off switching of the interface (super-)conductivity, while maintaining the usual, intrinsic characteristics for these LaAlO{sub 3}/SrTiO{sub 3} interfaces when no gate voltage is applied.
Eerkes, P. D.; Wiel, W. G. van der; Hilgenkamp, H. [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)] [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)
Selective Laser Melting Additive Manufacturing of TiC/AlSi10Mg Bulk-form Nanocomposites with Tailored Microstructures and Properties
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Abstract The nanoscale TiC particle reinforced AlSi10Mg nanocomposite parts were produced by selective laser melting (SLM) additive manufacturing process. The influence of laser energy density (LED) on densification behavior, microstructural evolution, microhardness and wear properties of SLM-processed TiC/AlSi10Mg nanocomposites was studied. It showed that the near fully dense nanocomposite parts (>98% theoretical density) were achieved with increasing the applied LED. The TiC reinforcement in SLM-processed parts experienced a microstructural change from the standard nanoscale particle morphology (the average size 77-93Ānm) to the relatively coarsened submicron structure (the mean particle size 154Ānm) as the LED increased.The sufficiently high densification rate combined with the homogeneousdistribution of nanoscale TiC reinforcement throughout the matrix led to a high microhardness of 181.2 HV0.2, a considerably low coefficient of friction (COF) of 0.36, and a reduced wear rate of 2.94ū10-5 mm3N-1m-1 for SLM-processed TiC/AlSi10Mg nanocomposite parts.
Dongdong Gu; Hongqiao Wang; Fei Chang; Donghua Dai; Pengpeng Yuan; Yves-Christian Hagedorn; Wilhelm Meiners
Stability of the L1{sub 2} phase at 800 C in the Ti-Al-Cr system
Interest in the L1{sub 2} phase, in the Ti-Al-Cr ternary system, continues due to the search for enhanced mechanical properties in light weight materials for possible structural applications. Additionally, recent work has indicated that alloys based in part on this phase may find use as protective alumina-forming coatings for {gamma}-based titanium-aluminides. In order to aid in the development of structural materials and coatings, the actual phase equilibria must be determined so that the correct processing schemes may be designed. Towards this end, the present work seeks to clarify some of the confusion pertaining to the phase equilibria of the L1{sub 2} phase.
Jewett, T.J.; Ahrens, B. [GKSS Research Centre, Geesthacht (Germany)] [GKSS Research Centre, Geesthacht (Germany); Dahms, M. [FH-Flensburg (Germany)] [FH-Flensburg (Germany)
Solution Processed Al-Doped ZnO Nanoparticles/TiOx Composite for Highly Efficient Inverted Organic Solar Cells
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Solution Processed Al-Doped ZnO Nanoparticles/TiOx Composite for Highly Efficient Inverted Organic Solar Cells ... This metal-oxide composition, called AZOTi, has two important elements that benefit production of low cost devices. ... After successful utilization of AZOTi in the fabrication of optimized single layer P3HT/PCBM-inverted solar cells, we also fabricated tandem cells comprising ITO/AZOTi/P3HT/PCBM in the front cell and a blend of a low band gap polymer [2,1,3-benzothiadiazole-4,7-diyl [4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b?]dithiophene-2,6-diyl
Abay Gadisa; Travis Hairfield; Leila Alibabaei; Carrie L. Donley; Edward T. Samulski; Rene Lopez
Feasibility study on preparation of coatings on Ti¢6Al¢4V by combined ultrasonic impact treatment and electrospark deposition
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Abstract A novel method combining ultrasonic impact treatment (UIT) with electrospark deposition was developed to prepare coatings on Ti¢6Al¢4V substrates. The microstructure, phase composition, residual stress, microhardness, and wear performance of the coating were studied, and new amorphous and nanocrystalline phases (titanium carbide nitride and iron titanium oxide) were found. In addition, the residual stress in the coating and in the substrate near the coating is compressive stress. The maximum compressive residual stress is about ?717ĀMPa, and its depth is about 470Ā?m. Because of contributions from multiple factors, the wear volume loss of the sample subjected to combined UIT and electrospark processing was reduced by four orders of magnitude compared with that of the base material.
Yang Liu; Dongpo Wang; Caiyan Deng; Lixing Huo; Lijun Wang; Shu Cao
Formation mechanism of linear friction welded Ti-6Al-4V alloy joint based on microstructure observation
The microstructure of the linear friction welded Ti-6Al-4V titanium alloy joint was investigated by optical microscope, scanning electronic microscope and transmission electron microscope. Results show that the dynamic recovery and recrystallization resulting from the intensive plastic deformation and fast heating and cooling processes during linear friction welding account for the superfine {alpha} + {beta} grains in the weld center. Fine {alpha} grains distribute in the {beta} matrix or at the boundaries of {beta} grains. A mass of dislocations networks and metastructures present within the {alpha} and {beta} grains. - Research Highlights: {yields} TEM is employed in the analysis. {yields} The dynamic recovery is the main mechanism in thermal deformation of TC4. {yields} Superfine grains in the weld result from dynamic recovery and dynamic recrystallizaion, but the recrystallization is inadequate.
Ma Tiejun; Chen Tao, E-mail: firstname.lastname@example.com; Li Wenya; Wang Shiwei; Yang Siqian
Microstructures and mechanical properties of Ti-6Al-4V welds with filler additions of tantalum and FS85
Many applications in the nuclear industry require that titanium alloys be welded to refractory metal alloys. Because of the widely dissimilar properties of these materials, the homogeneity of the fusion zone os of particular concern. To address this issue, a study was conducted to characterize the fusion zones of Ti-6Al-4V welds made with filler additions of tantalum and FS85 (Nb-28Wt%Ta-10wt%W-1wt%Zr). A goal of this study was to evaluate the feasibility of making microstructural predictions based on calculated fusion zone electron/atom (e/a) ratios. The welds were made by placing tantalum or FS85 shims between two pieces of 2.5 mm (0.1 in.) thick Ti-6Al-4V and making an electron beam weld along the length of the shim. With complete mixing, these shims were expected to produce fusion zone e/a ratios of 3.63{emdash}4.14 for the Ta series and 3.63{emdash}4.06 for the FS85 series, and microstructures consisting of {alpha}`, {alpha}`, and perhaps {omega}. The weld macro- and microstructures were characterized using optical and electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction. The mechanical properties of the welds were assessed using transverse and all-weld-metal tensile tests. The results showed a general increase in strength and decrease in ductility with increasing {beta} stabilizer level. As a result of this study, parameters were developed to increase the fusion zone size and increase mixing of the components. This work was performed at Sandia National Laboratories, supported by the U.S. Department of Energy under contract number DE-AC04-76DR00789, and at Los Alamos National Laboratory under contract number W-7405-ENG-36.
Damkroger, B.K.; Dixon, R.D.; Cotton, J.D.
Characterization of solid-phase welds between Ti-6Al-2Sn-4Zr-2Mo-0. 01Si and Ti-13. 5A1-21. 5Nb titanium aluminide
Dissimilar-alloy welds have been produced between Ti-6Al-2Sn-4Zr-2Mo-0.1Si (wt.%) and Ti-13.5Al-21.5Nb (wt.%) titanium aluminide using three different solid-phase welding processes that create significantly different thermo-mechanical conditions at the weld interface. Exposure to supertransus temperatures, appreciable deformation and rapid cooling of the weld interface region during linear-friction welding promote dynamic recrystallization of beta grains and beta decomposition to fine martensitic products. In contrast, diffusion welding at temperatures below the base metal beta transus temperatures and at relatively low pressures minimizes deformation and microstructural variations in the weld interface region relative to the unaffected base metal. During capacitor-discharge resistance spot welding, extremely rapid heating of the weld interface region to near-solidus temperatures, and subsequent rapid cooling, result in the formation of a metastable, ordered-beta microstructure in the Ti-13.5ASl-21.5Nb and fine alpha-prime martensite in the Ti-6Al-2Sn-4Zr-2Mo-0.1Si.
Baeslack, W.A. III; Juhas, M.; Fraser, H.L. (Ohio State Univ., Columbus, OH (United States)); Broderick, T.F. (Wright Labs., Wright Patterson AFB, OH (United States). Materials Directorate)
Epitaxial growth of metastable multiferroic AlFeO{sub 3} film on SrTiO{sub 3} (111) substrate
GaFeO{sub 3}-type AlFeO{sub 3} is consisted of oxygen octahedra and tetrahedra containing Al and Fe ions and is known to have a non-centrosymmetric polar structure with space group Pna2{sub 1}. We tried to grow epitaxial GaFeO{sub 3}-type AlFeO{sub 3} films on SrTiO{sub 3} (111) substrates by pulsed laser deposition technique. Both the atomic arrangement of close-packed and the atomic distance of the substrate surface played important roles in stabilizing GaFeO{sub 3}-type AlFeO{sub 3} on the substrate. Piezoresponse force microscopy measurements clearly showed that GaFeO{sub 3}-type AlFeO{sub 3} films have ferroelectricity at room temperature. In addition, AlFeO{sub 3} film also showed pinched-like hysteresis loop with T{sub N}???317?K.
Hamasaki, Yosuke; Shimizu, Takao; Taniguchi, Hiroki; Taniyama, Tomoyasu; Yasui, Shintaro; Itoh, Mitsuru, E-mail: email@example.com [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259-J2-19 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)
Thermo-Mechanical Model Development and Validation of DirectedEnergy Deposition Additive Manufacturing of Ti-6Al-4V
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Abstract A thermo-mechanical model of directed energy deposition additive manufacturing of Ti-6Al-4V is developed using measurements of the surface convection generated by gasses flowing during the deposition. In directed energy deposition, material is injected into a melt pool that is traversed to fill in a cross-section of a part, building it layer-by-layer. This creates large thermal gradients that generate plastic deformation and residual stresses. Finite element analysis (FEA) is often used to study these phenomena using simple assumptions of the surface convection. This work proposes that a detailed knowledge of the surface heat transfer is required to produce more accurate FEA results. The surface convection generated by the deposition process is measured and implemented in the thermo-mechanical model. Three depositions with different geometries and dwell times are used to validate the model using in situ measurements of the temperature and deflection as well as post-process measurements of the residual stress. An additional model is developed using the assumption of free convection on all surfaces. The results show that a measurement-based convection model is required to produce accurate simulation results.
J.C. Heigel; P. Michaleris; E.W. Reutzel
Analysis of Wear Mechanisms in Low Friction, Nanocomposite AlMgB14-TiB2 Coatings
Recent developments in coating science and technology offer new opportunities to enhance the energy-efficiency and performance of industrial machinery such as hydraulic fluid pumps and motors. The lubricated friction and wear characteristics of two wear-resistant coatings, diamond-like carbon and a nanocomposite material based on AlMgB{sub 14}-50 vol.% TiB{sub 2}, were compared in pin-on-disk tribotests using Mobil DTE-24{trademark} oil as the lubricant. In each case, the pins were fixed 9.53 mm diameter spheres of AISI 52100 steel, the load was 10 N, and the speed 0.5 m/s in all tests. Average steady-state friction coefficient values of 0.10 and 0.08 were measured for the DLC and nanocomposite, respectively. The coatings and their 52100 steel counterfaces were analyzed after the tests by X-ray photoelectron and Auger spectroscopy for evidence of material transfer or tribo-chemical reactions. The low-friction behavior of the boride nanocomposite coating is due to the formation of lubricative boric acid, B(OH){sub 3}. In contrast, the low-friction behavior of the DLC coating is related to the relatively low dielectric constant of the oil-based lubricant, leading to desorption of surface hydrogen from the coating.
Cook, Bruce A [Ames Laboratory; Harringa, J [Ames Laboratory; Anderegg, A [Ames Laboratory; Russell, A M [Iowa State University; Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Higdon, Clifton [Eaton Corporation; Elmoursi, Alaa A [Eaton Corporation
Category:Mason, IA | Open Energy Information
IA IA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Mason, IA" The following 16 files are in this category, out of 16 total. SVQuickServiceRestaurant Mason IA MidAmerican Energy Co (Iowa).png SVQuickServiceRestaura... 64 KB SVFullServiceRestaurant Mason IA MidAmerican Energy Co (Iowa).png SVFullServiceRestauran... 64 KB SVHospital Mason IA MidAmerican Energy Co (Iowa).png SVHospital Mason IA Mi... 73 KB SVLargeHotel Mason IA MidAmerican Energy Co (Iowa).png SVLargeHotel Mason IA ... 72 KB SVLargeOffice Mason IA MidAmerican Energy Co (Iowa).png SVLargeOffice Mason IA... 73 KB SVMediumOffice Mason IA MidAmerican Energy Co (Iowa).png SVMediumOffice Mason I... 69 KB SVMidriseApartment Mason IA MidAmerican Energy Co (Iowa).png
On the effect of deep-rolling and laser-peening on the stress-controlled low- and high-cycle fatigue behavior of Ti-6Al-4V at elevated temperatures up to 550?C
and near-?-titanium alloys, especially for fan bladebehavior of a titanium Ti-6Al-4V turbine fan blade alloy isfan blades and disks in aircraft jet propulsion engines are commonly made from titanium
Ritchie, IAltenberger, RKNalla, YSano LWagner, RO
Observation of strontium segregation in LaAlO{sub 3}/SrTiO{sub 3} and NdGaO{sub 3}/SrTiO{sub 3} oxide heterostructures by X-ray photoemission spectroscopy
LaAlO{sub 3} and NdGaO{sub 3} thin films of different thicknesses have been grown by pulsed laser deposition on TiO{sub 2}-terminated SrTiO{sub 3} single crystals and investigated by soft X-ray photoemission spectroscopy. The surface sensitivity of the measurements has been tuned by varying photon energy h? and emission angle ?. In contrast to the core levels of the other elements, the Sr 3d line shows an unexpected splitting for higher surface sensitivity, signaling the presence of a second strontium component. From our quantitative analysis we conclude that during the growth process Sr atoms diffuse away from the substrate and segregate at the surface of the heterostructure, possibly forming strontium oxide.
Treske, Uwe; Heming, Nadine; Knupfer, Martin; B³chner, Bernd; Koitzsch, Andreas, E-mail: email@example.com [Institute for Solid State Research, IFW-Dresden, P.O. Box 270116, DE-01171 Dresden (Germany); Di Gennaro, Emiliano; Scotti di Uccio, Umberto; Miletto Granozio, Fabio [CNR-SPIN and Dipartimento di Fisica, Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Naples (Italy); Krause, Stefan [Helmholtz-Zentrum Berlin, BESSY, Albert-Einstein-Str. 15, 12489 Berlin (Germany)
AL. EMERGENCY PREPAREDNESS SYLLABUS ATTACHMENT. EMERGENCY NOTIFICATION PROCEDURES are based on a simple concept - if you hear a.
New approaches for modeling type Ia supernovae
ich and J. Stein. On the thermonuclear runaway in Type IaSmall-Scale Stability of Thermonuclear Flames o in Type IaS. E. Woosley. The thermonuclear explosion of chandrasekhar
Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan
Quantum oscillations and subband properties of the two-dimensional electron gas at the LaAlO{sub 3}/SrTiO{sub 3} interface
We have performed high field magnetotransport measurements to investigate the interface electron gas in a high mobility SrTiO{sub 3}/SrCuO{sub 2}/LaAlO{sub 3}/SrTiO{sub 3} heterostructure. Shubnikov-de Haas oscillations reveal several 2D conduction subbands with carrier effective masses of 0.9m{sub e} and 2m{sub e}, quantum mobilities of order 2000 cm{sup 2}/VĀs, and band edges only a few millielectronvolts below the Fermi energy. Measurements in tilted magnetic fields confirm the 2D character of the electron gas, and show evidence of inter-subband scattering.
McCollam, A., E-mail: firstname.lastname@example.com; Guduru, V. K.; Zeitler, U.; Maan, J. C. [High Field Magnet Laboratory and Institute for Molecules and Materials, Radboud University Nijmegen, 6525 ED Nijmegen (Netherlands); Wenderich, S.; Kruize, M. K.; Molegraaf, H. J. A.; Huijben, M.; Koster, G.; Blank, D. H. A.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H. [Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands)
Excellent Passivation and Low Reflectivity Al2O3/TiO2 Bilayer Coatings for n-Wafer Silicon Solar Cells: Preprint
A bilayer coating of Al2O3 and TiO2 is used to simultaneously achieve excellent passivation and low reflectivity on p-type silicon. This coating is targeted for achieving high efficiency n-wafer Si solar cells, where both passivation and anti-reflection (AR) are needed at the front-side p-type emitter. It could also be valuable for front-side passivation and AR of rear-emitter and interdigitated back contact p-wafer cells. We achieve high minority carrier lifetimes {approx}1 ms, as well as a nearly 2% decrease in absolute reflectivity, as compared to a standard silicon nitride AR coating.
Lee, B. G.; Skarp, J.; Malinen, V.; Li, S.; Choi, S.; Branz, H. M.
Abstract IA37: Clinical genomics
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...Research. 15 October 2014 meeting-abstract Clinical Genomics Clinical Genomics: Oral Presentations - Invited Abstracts Abstracts...2013; San Diego, CA Abstract IA37: Clinical genomics Katherine A. Janeway Dana-Farber Cancer Institute...
Katherine A. Janeway
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Di Pillo, Gianni
E-Print Network 3.0 - al sistema cubano Sample Search Results
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String Landscape and Supernovae Ia
We present a model for the triggering of Supernovae Ia (SN Ia) by a phase transition to exact supersymmetry (susy) in the core of a white dwarf star. The model, which accomodates the data on SN Ia and avoids the problems of the standard astrophysical accretion based picture, is based on string landscape ideas and assumes that the decay of the false broken susy vacuum is enhanced at high density. In a slowly expanding susy bubble, the conversion of pairs of fermions to pairs of degenerate scalars releases a significant amount of energy which induces fusion in the surrounding normal matter shell. After cooling, the absence of degeneracy pressure causes the susy bubble to collapse to a black hole of about 0.1 solar mass or to some other stable susy object.
L. Clavelli
Effects of Reduction Temperature and Metal-Support Interactions on the Catalytic Activity of Pt/g-Al2O3 and Pt/TiO2 for the Oxidation of CO in the Presence and Absence of H2.
TiO2- and -Al2O3-supported Pt catalysts were characterized by HRTEM, XPS, EXAFS, and in situ FTIR spectroscopy after activation at various conditions, and their catalytic properties were examined for the oxidation of CO in the absence and presence of H2 (PROX). When {gamma}-Al{sub 2}O{sub 3} was used as the support, the catalytic, electronic, and structural properties of the Pt particles formed were not affected substantially by the pretreatment conditions. In contrast, the surface properties and catalytic activity of Pt/TiO2 were strongly influenced by the pretreatment conditions. In this case, an increase in the reduction temperature led to higher electron density on Pt, altering its chemisorptive properties, weakening the Pt-CO bonds, and increasing its activity for the oxidation of CO. The in situ FTIR data suggest that both the terminal and bridging CO species adsorbed on fully reduced Pt are active for this reaction. The high activity of Pt/TiO2 for the oxidation of CO can also be attributed to the ability of TiO2 to provide or stabilize highly reactive oxygen species at the metal-support interface. However, such species appear to be more reactive toward H{sub 2} than CO. Consequently, Pt/TiO{sub 2} shows substantially lower selectivities toward CO oxidation under PROX conditions than Pt/{gamma}-Al{sub 2}O{sub 3}.
Alexeev,O.; Chin, S.; Engelhard, M.; Ortiz-Soto, L.; Amiridis, M.
Nano-scratch behavior of a bulk Zr-10Al-5Ti-17.9Cu-14.6Ni amorphous alloy
The tribological behavior of a Zr-10Al-5Ti-17.9Cu-14.6Ni (at.%) bulk amorphous alloy, in both the as-cast and annealed states, was investigated using nano-scratch tests, including ramping load scratch and multiple sliding wear techniques. The crystallization sequence of the alloy was also characterized. Mechanical properties, such as Young's modulus, hardness, friction coefficient, and tribological wear were measured. These properties were found to vary with microstructure. In general, an increase in annealing temperature results in an increase in hardness, which in turn produces a decrease in friction coefficient but an increase in wear resistance. Samples having a structure consisting of supercooled liquid matrix with dispersed nanocrystalline particles exhibit the best wear performance. (c) 2000 Materials Research Society.
Wang, J. G. [Chemistry and Materials Science, Lawrence Livermore National Laboratory, P.O. Box 808, L-350, Livermore, California 94551-9900 (United States); Choi, B. W. [Chemistry and Materials Science, Lawrence Livermore National Laboratory, P.O. Box 808, L-350, Livermore, California 94551-9900 (United States); Nieh, T. G. [Chemistry and Materials Science, Lawrence Livermore National Laboratory, P.O. Box 808, L-350, Livermore, California 94551-9900 (United States); Liu, C. T. [Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6376 (United States)
Role of oxygen vacancies in magnetic properties of LaAlO{sub 3}/SrTiO{sub 3} interface
The interface of two band-insulators SrTiO{sub 3} and LaAlO{sub 3} exhibits a highly conducting two-dimensional electron gas which shows low-temperature superconductivity, ferromagnetism and many other novel properties. Several studies reveal that the oxygen vacancies at the interface have strong influence on the electronic and magnetic properties of the interface electrons. Here, we develop an insight into the effects of oxygen vacancies on the magnetic properties of the system; the oxygen vacancies help in establishing ferromagnetism which competes with superconductivity at low temperatures. Simulated Monte-Carlo annealing suggests an ordering of the oxygen vacant sites and sheds light on the experimental observation of the quenching of magnetic moment on annealing. A possible explanation for the coexistence of superconductivity and ferromagnetism is also discussed.
Mohanta, N., E-mail: email@example.com [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, West Bengal-721302 (India); Taraphder, A. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, West Bengal-721302, India and Centre for Theoretical Studies, Indian Institute of Technology Kharagpur, West Bengal-721302 (India)
Structure and Properties of Composite Electrospark, Laser, and Magnetron Deposited AlN ? TiB2 Coatings
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A comparative investigation of the coatings produced by electrospark alloying, laser gas-powder deposition, and magnetron sputtering using composite AlN ?...2...material was carried out. It is shown that the pres...
Irina A. Podchernyaeva
Effect of the strain-induced melt activation (SIMA) process on the tensile properties of a new developed super high strength aluminum alloy modified by Al-5Ti-1B grain refiner
In this study, the effect of Al-5Ti-1B grain refiners and modified strain-induced melt activation process on an Al-Zn-Mg-Cu alloy was studied. The optimum level of Ti was found to be 0.1 wt.%. The specimens subjected to deformation ratio of 40% (at 300 Degree-Sign C) and various heat treatment times (10-40 min) and temperature (550-600 Degree-Sign C) regimes were characterized in this study. Reheating condition to obtain a fine globular microstructure was optimized. Microstructural examinations were conducted by optical and scanning electron microscopy coupled with an energy dispersive spectrometry. The optimum temperature and time in strain-induced melt activation process are 575 Degree-Sign C and 20 min, respectively. T6 heat treatment including quenching to room temperature and aging at 120 Degree-Sign C for 24 h was employed to reach to the maximum strength. Significant improvements in mechanical properties were obtained with the addition of grain refiner combined with T6 heat treatment. After the T6 heat treatment, the average tensile strength increased from 283 MPa to 587 and 332 MPa to 617 for samples refined with 2 wt.% Al-5Ti-1B before and after strain-induced melt activation process and extrusion process, respectively. Ultimate strength of Ti-refined specimens without SIMA process has a lower value than globular microstructure specimens after SIMA and extrusion process. - Highlights: Black-Right-Pointing-Pointer The effect of Al-5Ti-1B on the aluminum alloy produced by SIMA process was studied. Black-Right-Pointing-Pointer Al-5Ti-1B is an effective in reducing the grain and reagent fine microstructure. Black-Right-Pointing-Pointer Reheating condition to obtain a fine globular microstructure was optimized. Black-Right-Pointing-Pointer The optimum temperature and time in SIMA process are 575 Degree-Sign C and 20 min respectively. Black-Right-Pointing-Pointer UTS of globular structure specimens have a more value than Ti-refined specimens.
Haghparast, Amin [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)] [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Nourimotlagh, Masoud [Young Researchers Club, Dareshahr Branch, Islamic Azad university (Iran, Islamic Republic of)] [Young Researchers Club, Dareshahr Branch, Islamic Azad university (Iran, Islamic Republic of); Alipour, Mohammad, E-mail: email@example.com [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)
Stellar Populations and the White Dwarf Mass Function: Connections To Supernova Ia Luminosities
We discuss the luminosity function of SNe Ia under the assumption that recent evidence for dispersion in this standard candle is related to variations in the white dwarf mass function (WDMF) in the host galaxies. We develop a simple parameterization of the WDMF as a function of age of a stellar population and apply this to galaxies of different morphological types. We show that this simplified model is consistent with the observed WDMF of Bergeron et al. (1992) for the solar neighborhood. Our simple models predict that WDMF variations can produce a range of more than 1.8 mag in M$_B$(SN Ia), which is comparable to the observed value using the data of Phillips (1993) and van den Bergh (1996). We also predict a galaxy type dependence of M$_B$(SN Ia) under standard assumptions of the star formation history in these galaxies and show that M$_B$(SN Ia) can evolve with redshift. In principle both evolutionary and galaxy type corrections should be applied to recover the intrinsic range of M$_B$(SN Ia) from the observed values. Our current inadequate knowledge of the star formation history of galaxies coupled with poor physical understanding of the SN Ia mechanism makes the reliable estimation of these corrections both difficult and controversial. The predictions of our models combined with the observed galaxy and redshift correlations may have the power to discriminate between the Chandrasekhar and the sub-Chandrasekhar progenitor scenarios for SNe Ia.
Ted von Hippel; G. D. Bothun; R. A. Schommer
Tensile properties and strain rate sensitivity of Ti-47Al-2Cr-0.2Si sheet material with different microstructures
New materials based on gamma titanium aluminides (gamma alloys) have emerged as potential candidates for high temperature applications such as aerospace structural components (e.g., airframes, turbine components, thermal protection systems) and automotive parts (e.g., exhaust valves, turbocharger rotors). Because of their low density, high Young`s modulus, high-temperature strength retention, good oxidation and burn resistance, the so-called second generation gamma alloys are able to exceed the application temperature of advanced titanium alloys and also to replace nickel- and iron-based superalloys up to 800C. However, poor formability and low room temperature (RT) ductility resulting in low fracture toughness have limited possible applications. The present paper deals with the dependence of tensile properties of Ti-47Al-2Cr-0.2Si (composition in atomic-%) sheet material on microstructure and test conditions. Four different microstructures, i.e., fine-grained primary annealed (PA), near gamma (NG), duplex (DU) as well as coarse-grained fully lamellar (FL) have been investigated with emphasis on the influence of grain size, phase distribution, and strain rate on tensile properties at 700 C. Fractography was conducted by scanning electron microscopy (SEM) to examine the influence of temperature on the fracture behavior and to determine the onset of dynamic recrystallization effects.
Clemens, H. [Plansee AG, Reutte (Austria)] [Plansee AG, Reutte (Austria); Glatz, W. [Montanuniversitaet, Leoben (Austria). Inst. fuer Metallkunde und Werkstoffpruefung] [Montanuniversitaet, Leoben (Austria). Inst. fuer Metallkunde und Werkstoffpruefung; Appel, F. [GKSS Research Centre, Geesthacht (Germany). Inst. for Materials Research] [GKSS Research Centre, Geesthacht (Germany). Inst. for Materials Research
EFFECTS OF ION IRRADIATION ON Zr52.5Cu17.9Ni14.6Al10Ti5 (BAM-11) BULK METALLIC GLASS
Bulk metallic glasses are intriguing candidates for nuclear applications due to their inherent amorphous structure, but their radiation response is largely unknown due to the relatively recent nature of innovations in bulk metallic glass fabrication. Here, microstructural and mechanical property evaluations have been performed on a Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass (BAM-11) irradiated with 3 MeV Ni+ ions to 0.1 and 1.0 dpa at room temperature and 200 C. Nanoindentation hardness and Young s modulus both decreased by 6 to 20% in samples irradiated at room temperature, with the sample irradiated to 1.0 dpa experiencing the greatest change in mechanical properties. However, no significant changes in properties were observed in the samples irradiated at 200 C, and transmission electron microscopy showed no visible evidence of radiation damage or crystallization following ion irradiation at any of the tested conditions. These results suggest that BAM-11 bulk metallic glass may be useful for certain applications in nuclear environments.
Perez-Bergquist, Alex G [ORNL] [ORNL; Bei, Hongbin [ORNL] [ORNL; Leonard, Keith J [ORNL] [ORNL; Zhang, Yanwen [ORNL] [ORNL; Zinkle, Steven J [ORNL] [ORNL
FTIR study of hydrogen and carbon monoxide adsorption on Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3}
The Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3} catalysts submitted to low-temperature reduction (LTR,200 C) and high-temperature reduction (HTR, 500 C) and exposed to hydrogen and carbon monoxide at room temperature were studied by infrared spectroscopy. There is a strong loss of transmission in the entire infrared spectra on Pt/TiO{sub 2} after its exposure to hydrogen, which is related to the reducibility of the support. A typical SMSI behavior (strong metal-support interaction), such as the decrease in carbon monoxide adsorption capacity, was detected on Pt/TiO{sub 2} and Pt/ZrO{sub 2} after exposure to hydrogen, even for the catalysts submitted to LTR treatment. Also a carbonyl band shift to lower wavenumber was observed on LTR-treated Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3} after exposure to hydrogen. The authors interpreted this SMSI behavior as an electronic rather than morphological effect, which was induced by the presence of hydrogen spillover.
Benvenutti, E.V.; Franken, L.; Moro, C.C.; Davanzo, C.U.
Type Ia supernova rate at a redshift of ~;0.1
We present the type Ia rate measurement based on two EROS supernova search campaigns (in 1999 and 2000). Sixteen supernovae identified as type Ia were discovered. The measurement of the detection efficiency, using a Monte Carlo simulation, provides the type Ia supernova explosion rate at a redshift {approx} 0.13. The result is 0.125{sub -0.034-0.028}{sup +0.044+0.028} h{sub 70}{sup 2} SNu where 1 SNu = 1 SN/10{sup 10} L{sub {circle_dot}}{sup B}/century. This value is compatible with the previous EROS measurement (Hardin et al. 2000), done with a much smaller sample, at a similar redshift. Comparison with other values at different redshifts suggests an evolution of the type Ia supernova rate.
Blanc, G.; Afonso, C.; Alard, C.; Albert, J.N.; Aldering, G.; Amadon, A.; Andersen, J.; Ansari, R.; Aubourg, E.; Balland, C.; Bareyre,P.; Beaulieu, J.P.; Charlot, X.; Conley, A.; Coutures, C.; Dahlen, T.; Derue, F.; Fan, X.; Ferlet, R.; Folatelli, G.; Fouque, P.; Garavini, G.; Glicenstein, J.F.; Goldman, B.; Goobar, A.; Gould, A.; Graff, D.; Gros,M.; Haissinski, J.; Hamadache, C.; Hardin, D.; Hook, I.M.; deKat, J.; Kent, S.; Kim, A.; Lasserre, T.; LeGuillou, L.; Lesquoy, E.; Loup, C.; Magneville, C.; Marquette, J.B.; Maurice, E.; Maury, A.; Milsztajn, A.; Moniez, M.; Mouchet, M.; Newberg, H.; Nobili, S.; Palanque-Delabrouille,N.; Perdereau, O.; Prevot, L.; Rahal, Y.R.; Regnault, N.; Rich, J.; Ruiz-Lapuente, P.; Spiro, M.; Tisserand, P.; Vidal-Madjar, A.; Vigroux,L.; Walton, N.A.; Zylberajch, S.
Fabrication and crystal line patterning of Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} ion conductive glass by Ni atom heat processing method
Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} conductive crystal lines composed of closely compacted fine particles were patterned on the surface of 13.9Li{sub 2}O-8.9Al{sub 2}O{sub 3}-37.6TiO{sub 2}-38.6P{sub 2}O{sub 5}-1NiO (mol %) precursor glass by a continuous wave Yb fiber laser irradiation ({lambda}=1078 nm) using the nickel atom heat processing method. Homogeneous and smooth crystal lines with a uniform width of 30 {mu}m were obtained with a laser power of 1.3 W. The Li{sup +} ion conductivity of the laser patterned glass was about two orders of magnitude higher than that of the glass matrix due to the formation of Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} conductive crystalline phase by Yb fiber laser irradiation.
Pang, Maolin; Suzuki, Ryota; Saito, Makoto; Machida, Ken-ichi; Hanzawa, Hiromasa; Nojiri, Yoshihiro; Tanase, Shigeo [Center for Advanced Science and Innovation, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Graduate School of Engineering Science, Osaka Univeristy, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), Kansai Center, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)
Steamboat IA Geothermal Facility | Open Energy Information
IA Geothermal Facility IA Geothermal Facility Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Steamboat IA Geothermal Facility General Information Name Steamboat IA Geothermal Facility Facility Steamboat IA Sector Geothermal energy Location Information Location Washoe, Nevada Coordinates 40.5608387┬░, -119.6035495┬░ Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":40.5608387,"lon":-119.6035495,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
THE LOCAL HOSTS OF TYPE Ia SUPERNOVAE
We use multi-wavelength, matched aperture, integrated photometry from the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the RC3 to estimate the physical properties of 166 nearby galaxies hosting 168 well-observed Type Ia supernovae (SNe Ia). The ultraviolet (UV) imaging of local SN Ia hosts from GALEX allows a direct comparison with higher-redshift hosts measured at optical wavelengths that correspond to the rest-frame UV. Our data corroborate well-known features that have been seen in other SN Ia samples. Specifically, hosts with active star formation produce brighter and slower SNe Ia on average, and hosts with luminosity-weighted ages older than 1 Gyr produce on average more faint, fast, and fewer bright, slow SNe Ia than younger hosts. New results include that in our sample, the faintest and fastest SNe Ia occur only in galaxies exceeding a stellar mass threshold of approx10{sup 10} M{sub sun}, leading us to conclude that their progenitors must arise in populations that are older and/or more metal rich than the general SN Ia population. A low host extinction subsample hints at a residual trend in peak luminosity with host age, after correcting for light-curve shape, giving the appearance that older hosts produce less-extincted SNe Ia on average. This has implications for cosmological fitting of SNe Ia, and suggests that host age could be useful as a parameter in the fitting. Converting host mass to metallicity and computing {sup 56}Ni mass from the supernova light curves, we find that our local sample is consistent with a model that predicts a shallow trend between stellar metallicity and the {sup 56}Ni mass that powers the explosion, but we cannot rule out the absence of a trend. We measure a correlation between {sup 56}Ni mass and host age in the local universe that is shallower and not as significant as that seen at higher redshifts. The details of the age-{sup 56}Ni mass correlations at low and higher redshift imply a luminosity-weighted age threshold of approx3 Gyr for SN Ia hosts, above which they are less likely to produce SNe Ia with {sup 56}Ni masses above approx0.5 M{sub sun}.
Neill, James D.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Wyder, Ted K. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Sullivan, Mark [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102, Goleta, CA 93117 (United States); Conley, Alex [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ONM5S3H8 (Canada); Seibert, Mark; Madore, Barry F. [The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA, 91101 (United States); Neff, Susan G. [Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Schiminovich, David [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Bianchi, Luciana [Center for Astrophysical Sciences, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Donas, Jose; Milliard, Bruno [Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France); Heckman, Timothy M. [Department of Physics and Astronomy, Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Lee, Young-Wook [Center for Space Astrophysics, Yonsei University, Seoul 120-749 (Korea, Republic of); Rich, R. Michael [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
Supersoft Sources as SN Ia Progenitors
of the existence of supersoft X┬Łray sources. It is argued that SNe Ia are thermonuclear explosions of accreting C is that they represent thermonuclear disruptions of mass accreting white dwarfs (WDs). Thus, the basic ingredient
Greiner, Jochen
CONSERVATIVOS ENERG #19; IA-MOMENTO Jos#19;e M. Goicolea Ruig#19;omez y Juan Carlos Garc#19;#16;a Orden EscuelaM #19; ETODOS NUM #19; ERICOS EN INGENIER #19; IA R. Abascal, J. Dom#19;#16;nguez y G. Bugeda (Eds.upm.es Palabras clave: Din#19;amica no lineal, mecanismos, sistemas multicuerpo exibles, energ#19;#16;a- momento
Romero, Ignacio
Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame
Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame S. E of these regions can be supersonic and could initiate a detonation. Subject headings: supernovae: general a late time transition of the thermonuclear burning to a detonation wave (e.g., Hoflich et al. 1995
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NE NE EX XT T G GE EN NE ER RA AT TI IO ON N S SA AF FE EG GU UA AR RD DS S I IN NI IT TI IA AT TI IV VE E ( (N NG GS SI I) ) O OP PP PO OR RT TU UN NI IT TI IE ES S F FO OR R S ST TU UD DE EN NT TS S A AN ND D Y YO OU UN NG G P PR RO OF FE ES SS SI IO ON NA AL LS S I IN NT TE ER RE ES ST TE ED D I IN N S SA AF FE EG GU UA AR RD DS S/ /N NO ON NP PR RO OL LI IF FE ER RA AT TI IO ON N The Next Generation Safeguards Initiative (NGSI) was launched by the National Nuclear Security Administration (NNSA) in FY 2008 to develop the policies, concepts, technologies, expertise, and infrastructure necessary to strengthen and sustain the international safeguards system as it evolves to meet new challenges over the next 25 years. NGSI's Human Capital Development subprogram 1 aims to revitalize and expand the international safeguards human capital base in the United States by attracting, educating, training, and retaining
Rolling Hills (IA) | Open Energy Information
Rolling Hills (IA) Rolling Hills (IA) Jump to: navigation, search Name Rolling Hills (IA) Facility Rolling Hills (IA) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner MidAmerican Energy Company Developer MidAmerican Energy Company Energy Purchaser MidAmerican Energy Company Location Massena IA Coordinates 41.230443┬░, -94.75459┬░ Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":41.230443,"lon":-94.75459,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
LBNL-4183E-rev1 N NA AT TU UR RA AL L G GA AS S V VA AR RI
NLE Websites -- All DOE Office Websites (Extended Search)
4183E-rev1 4183E-rev1 N NA AT TU UR RA AL L G GA AS S V VA AR RI IA AB BI IL LI IT TY Y I IN N C CA AL LI IF FO OR RN NI IA A: : E EN NV VI IR RO ON NM ME EN NT TA AL L I IM MP PA AC CT TS S A AN ND D D DE EV VI IC CE E P PE ER RF FO OR RM MA AN NC CE E E EX XP PE ER RI IM ME EN NT TA AL L E EV VA AL LU UA AT TI IO ON N O OF F I IN NS ST TA AL LL LE ED D C CO OO OK KI IN NG G E EX XH HA AU US ST T F FA AN N P PE ER RF FO OR RM MA AN NC CE E Brett C. Singer, William W. Delp and Michael G. Apte Indoor Environment Department Atmospheric Sciences Department Environmental Energy Technologies Division July 2011 (Revised February 2012) Disclaimer 1 This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of
PRODUCTION OF {sup 26}Al, {sup 44}Ti, AND {sup 60}Fe IN CORE-COLLAPSE SUPERNOVAE: SENSITIVITY TO THE RATES OF THE TRIPLE ALPHA AND {sup 12}C({alpha}, {gamma}){sup 16}O REACTIONS
We have studied the sensitivity to variations in the triple alpha and {sup 12}C({alpha}, {gamma}){sup 16}O reaction rates of the production of {sup 26}Al, {sup 44}Ti, and {sup 60}Fe in core-collapse supernovae (SNe). We used the KEPLER code to model the evolution of 15 M {sub sun}, 20 M {sub sun}, and 25 M {sub sun} stars to the onset of core collapse and simulated the ensuing SN explosion using a piston model for the explosion and an explosion energy of 1.2 x 10{sup 51} erg. Calculations were performed for the Anders and Grevesse and Lodders abundances. Over a range of twice the experimental uncertainty, {sigma}, for each helium-burning rate, the production of {sup 26}Al, {sup 60}Fe, and their ratio vary by factors of 5 or more. For some species, similar variations were observed for much smaller rate changes, 0.5{sigma} or less. The production of {sup 44}Ti was less sensitive to changes in the helium-burning rates. Production of all three isotopes depended on the solar abundance set used for the initial stellar composition.
Tur, Clarisse; Austin, Sam M. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Laboratory, East Lansing, MI 48824-1321 (United States); Heger, Alexander, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455-0149 (United States)
Phase Relations and Elemental Distribution Among Co-Existing Phases in the Ceramics of the Pseudobinary System CaZrTi{sub 2}O{sub 7}-LnAlO{sub 3} (Ln= Nd, Sm)
In the ceramics in series (1-x) CaZrTi{sub 2}O{sub 7} - x NdAlO{sub 3} and (1-x) CaZrTi{sub 2}O{sub 7} - x SmAlO{sub 3} (x = 0.25, 0.5 and 0.75) produced by cold pressing and sintering at 1400, 1450 and 1500 deg. C zirconolite was found to be a major phase, perovskite was an extra phase and traces of residual baddeleyite occurred. At x = 0.75 the perovskite was major phase and zirconolite and cubic oxide of fianite or tazheranite type were extra phases. Major Nd and Sm host phase at x = 0.25 was found to be zirconolite (about 65% of total Nd{sub 2}O{sub 3} and 74% of total Sm{sub 2}O{sub 3}). With the x value increasing perovskite becomes major host phase for Nd and Sm accumulating of up to about 92% of total Nd and about 72% of total Sm. As follows from SEM/EDS data Nd and Sm contents in the zirconolite may reach {approx}1 formula unit (fu). (authors)
Mikhailenko, Natalia [SIA Radon, Moscow, 119121 (Russian Federation); Stefanovsky, Sergey [Center of Advanced Technologies, SIA Radon, 7th Rostovskii lane 2/14, Moscow, 119121 (Russian Federation); Ochkin, Alexander [D. Mendeleev University of Chemical Technology, Moscow (Russian Federation)
Hai un'idea di impresa? La Regione Veneto ti aiuta a realizzarla La Direzione Lavoro della Regione Veneto partecipa al progetto I. E. SMART -Smart Training
Veneto partecipa al progetto I. E. SMART - Smart Training Network for Innovation and Entrepreneurship Competition ├© un concorso di idee che si svolge in pi├╣ fasi: dal 1┬░ agosto al 30 ottobre 2013 si raccolgono le idee presentate tramite il formulario on line che trovi collegandoti al seguente link: http
Romeo, Alessandro
KPD1930+2752 - a candidate Type Ia supernova progenitor
We present spectra of the pulsating sdB star KPD1930+2752 which confirm that this star is a binary. The radial velocities measured from the H-alpha and HeI6678 spectral lines vary sinusoidally with the same period (2h 17m) as the ellipsoidal variability seen by Billeres et al. (2000). The amplitude of the orbital motion (349.3+-2.7 km/s) combined with the canonical mass for sdB stars (0.5 solar masses) implies a total mass for the binary of 1.47+-0.01 solar masses The unseen companion star is almost certainly a white dwarf star. The binary will merge within about 200 million years due to gravitational wave radiation. The accretion of helium and other elements heavier than hydrogen onto the white dwarf which then exceeds the Chandrasekhar mass (1.4 solar masses) is a viable model for the cause of Type Ia supernovae. KPD1930+2752 is the first star to be discovered which is a good candidate for the progenitor of a Type Ia supernova of this type which will merge on an astrophysically interesting timescale.
P. F. L. Maxted; T. R. Marsh; R. C. North
Search for progenitors of supnernovae type Ia with SPY
We have started a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY). About 400 white dwarfs were checked for radial velocity variations during the first 15 months of this project, twice the number of white dwarfs investigated during the last 20 years. We give an overview of the SPY project and present first results Fifty four new DDs have been discovered, seven of them double lined (only 18 and 6 objects of these groups were known before, respectively). The final sample is expected to contain 150 to 200 DDs. Eight new pre-cataclysmic binaries were also detected. SPY is the first DD survey which encompasses also non-DA white dwarfs. SPY produces an immense, unique sample of very high resolution white dwarf spectra, which provides a lot of spin-off opportunities. We describe our projects to exploit the SPY sample for the determination of basic parameters, kinematics, and rotational velocities of white dwarfs. A catalogue with a first subset of our white dwarf data has already been published by Koester et al. 2001.
R. Napiwotzki; N. Christlieb; H. Drechsel; H. -J. Hagen; U. Heber; D. Homeier; C. Karl; D. Koester; B. Leibundgut; T. R. Marsh; S. Moehler; G. Nelemans; E. -M. Pauli; D. Reimers; A. Renzini; L. Yungelson
A threat-based definition of IA and IA-enabled products.
This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.
Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche
A threat-based definition of IA- and IA-enabled products.
This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.
Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche
Comparison of Recent SnIa datasets
We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization $w(a)=w_0+w_1 (1-a)$, according to their Figure of Merit (FoM), their consistency with the cosmological constant ($\\Lambda$CDM), their consistency with standard rulers (Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)) and their mutual consistency. We find a significant improvement of the FoM (defined as the inverse area of the 95.4% parameter contour) with the number of SnIa of these datasets ((C) highest FoM, (U), (G), (D), (E), (S) lowest FoM). Standard rulers (CMB+BAO) have a better FoM by about a factor of 3, compared to the highest FoM SnIa dataset (C). We also find that the ranking sequence based on consistency with $\\Lambda$CDM is identical with the corresponding ranking based on consistency with standard rulers ((S) most consistent, (D), (C), (E), (U), (G) least consistent). The ranking sequence of the datasets however changes when we consider the consistency with an expansion history corresponding to evolving dark energy $(w_0,w_1)=(-1.4,2)$ crossing the phantom divide line $w=-1$ (it is practically reversed to (G), (U), (E), (S), (D), (C)). The SALT2 and MLCS2k2 fitters are also compared and some peculiar features of the SDSS-II dataset when standardized with the MLCS2k2 fitter are pointed out. Finally, we construct a statistic to estimate the internal consistency of a collection of SnIa datasets. We find that even though there is good consistency among most samples taken from the above datasets, this consistency decreases significantly when the Gold06 (G) dataset is included in the sample.
J. C. Bueno Sanchez; S. Nesseris; L. Perivolaropoulos
CfA4: LIGHT CURVES FOR 94 TYPE Ia SUPERNOVAE
We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055-0.073, obtained between 2006 and 2011. There are a total of 5522 light-curve points. We show that our natural-system SN photometry has a precision of {approx}< 0.03 mag in BVr'i', {approx}< 0.06 mag in u', and {approx}< 0.07 mag in U for points brighter than 17.5 mag and estimate that it has a systematic uncertainty of 0.014, 0.010, 0.012, 0.014, 0.046, and 0.073 mag in BVr'i'u'U, respectively. Comparisons of our standard-system photometry with published SN Ia light curves and comparison stars reveal mean agreement across samples in the range of {approx}0.00-0.03 mag. We discuss the recent measurements of our telescope-plus-detector throughput by direct monochromatic illumination by Cramer et al. This technique measures the whole optical path through the telescope, auxiliary optics, filters, and detector under the same conditions used to make SN measurements. Extremely well characterized natural-system passbands (both in wavelength and over time) are crucial for the next generation of SN Ia photometry to reach the 0.01 mag accuracy level. The current sample of low-z SNe Ia is now sufficiently large to remove most of the statistical sampling error from the dark-energy error budget. But pursuing the dark-energy systematic errors by determining highly accurate detector passbands, combining optical and near-infrared (NIR) photometry and spectra, using the nearby sample to illuminate the population properties of SNe Ia, and measuring the local departures from the Hubble flow will benefit from larger, carefully measured nearby samples.
Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Falco, Emilio; Fernandez, Jose; Friedman, Andrew S.; Groner, Ted; Hartman, Joel [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Rest, Armin [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Cramer, Claire E. [NIST (National Institute of Standards and Technology), Gaithersburg, MD 20899 (United States); Wood-Vasey, W. Michael [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Currie, Thayne [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); De Kleer, Kathy [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Esquerdo, Gil; Everett, Mark, E-mail: firstname.lastname@example.com [Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719 (United States); and others
Testing the Distance¢Duality Relation with Galaxy Clusters and Type Ia Supernovae
Science Journals Connector (OSTI)
In this Letter, we propose a new and model-independent cosmological test for the distance-duality (DD) relation, ? = DL (z)(1 + z)¢2/DA (z) = 1, where DL and DA are, respectively, the luminosity and angular diameter distances. For DL we consider two sub-samples of Type Ia supernovae (SNe Ia) taken from Constitution data whereas DA distances are provided by two samples of galaxy clusters compiled by De Filippis etĀal. and Bonamente etĀal. by combining Sunyaev-Zeldovich effect and X-ray surface brightness. The SNe Ia redshifts of each sub-sample were carefully chosen to coincide with the ones of the associated galaxy cluster sample (?z DA (z) ? DL (z), we have tested the DD relation by assuming that ? is a function of the redshift parameterized by two different expressions: ?(z) = 1 + ?0 z and ?(z) = 1 + ?0 z/(1 + z), where ?0 is a constant parameter quantifying a possible departure from the strict validity of the reciprocity relation (?0 = 0). In the best scenario (linear parameterization), we obtain ?0 = ¢0.28+0.44 ¢0.44 (2?, statistical + systematic errors) for the De Filippis etĀal. sample (elliptical geometry), a result only marginally compatible with the DD relation. However, for the Bonamente etĀal. sample (spherical geometry) the constraint is ?0 = ¢0.42+0.34 ¢0.34 (3?, statistical + systematic errors), which is clearly incompatible with the duality-distance relation.
R. F. L. Holanda; J. A. S. Lima; M. B. Ribeiro
Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable
Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable
SAE Aerospace Standards. London
Category:Des Moines, IA | Open Energy Information
IA IA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Des Moines, IA" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Des Moines IA MidAmerican Energy Co (Iowa).png SVFullServiceRestauran... 64 KB SVQuickServiceRestaurant Des Moines IA MidAmerican Energy Co (Iowa).png SVQuickServiceRestaura... 64 KB SVHospital Des Moines IA MidAmerican Energy Co (Iowa).png SVHospital Des Moines ... 73 KB SVLargeHotel Des Moines IA MidAmerican Energy Co (Iowa).png SVLargeHotel Des Moine... 72 KB SVLargeOffice Des Moines IA MidAmerican Energy Co (Iowa).png SVLargeOffice Des Moin... 73 KB SVMediumOffice Des Moines IA MidAmerican Energy Co (Iowa).png SVMediumOffice Des Moi... 69 KB SVMidriseApartment Des Moines IA MidAmerican Energy Co (Iowa).png
Microstructure and mechanical properties of Ni-based composite coatings reinforced by in situ synthesized TiB2 + TiC by laser cladding
Science Journals Connector (OSTI)
A Ni-based composite coating reinforced by in situ synthesized TiB2...and TiC particles was fabricated on Ti6Al4V by laser cladding. An attempt was made to correlate the...2, flower-like or equiaxial TiC, and fin...
Jun Li; Xuan-jun Zhang; Hui-ping Wangģ
Type Ia Supernova Hubble Residuals and Host-Galaxy Properties
Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spec- trophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ? 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at ? 1?, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement the Hubble residual step with host mass is 0.045 ? 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch param- eters: Steps at> 2? significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light- curve width and color around peak (similar to the?m15 and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20 to 30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.
Nearby Supernova Factory; Kim, A. G.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Feindt, U.; Fleury, M.; Gangler, E.; Greskovic, P.; Guy, J.; Kowalski, M.; Lombardo, S.; Nordin, J.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.
DOE - Office of Legacy Management -- Bendix Aviation Corp Pioneer Div - IA
Office of Legacy Management (LM)
Bendix Aviation Corp Pioneer Div - Bendix Aviation Corp Pioneer Div - IA 05 FUSRAP Considered Sites Site: BENDIX AVIATION CORP., PIONEER DIV. (IA.05 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Pioneer Division, Bendix Aviation Corporation Bendix Aviation Corporation Bendix Pioneer Division IA.05-1 IA.05-2 IA.05-3 Location: Davenport , Iowa IA.05-1 Evaluation Year: 1990 IA.05-2 IA.05-4 Site Operations: Conducted studies to investigate the feasibility of using sonic cleaning equipment to decontaminate uranium contaminated drums. IA.05-1 Site Disposition: Eliminated - Potential for contamination considered remote based on limited operations at the site IA.05-2 IA.05-4 IA.05-5 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Uranium IA.05-1
DOE - Office of Legacy Management -- Titus Metals - IA 04
Office of Legacy Management (LM)
from consideration under FUSRAP Also see Documents Related to TITUS METALS IA.04-1 - Argonne National Laboratory Memorandum; Lonergan to Novak; Subject: Extrusion of Billets,...
Conformal cosmological model and SNe Ia data
Now there is a huge scientific activity in astrophysical studies and cosmological ones in particular. Cosmology transforms from a pure theoretical branch of science into an observational one. All the cosmological models have to pass observational tests. The supernovae type Ia (SNe Ia) test is among the most important ones. If one applies the test to determine parameters of the standard Friedmann-Robertson-Walker cosmological model one can conclude that observations lead to the discovery of the dominance of the {Lambda} term and as a result to an acceleration of the Universe. However, there are big mysteries connected with an origin and an essence of dark matter (DM) and the {Lambda} term or dark energy (DE). Alternative theories of gravitation are treated as a possible solution of DM and DE puzzles. The conformal cosmological approach is one of possible alternatives to the standard {Lambda}CDM model. As it was noted several years ago, in the framework of the conformal cosmological approach an introduction of a rigid matter can explain observational data without {Lambda} term (or dark energy). We confirm the claim with much larger set of observational data.
Zakharov, A. F., E-mail: firstname.lastname@example.com [National Astronomical Observatories of Chinese Academy of Sciences (China); Pervushin, V. N. [Joint Institute for Nuclear Research, Bogoliubov Laboratory for Theoretical Physics (Russian Federation)
Type Ia Supernova Explosion: Gravitationally Confined Detonation
Science Journals Connector (OSTI)
We present a new mechanism for Type Ia supernova explosions in massive white dwarfs. The scenario follows from relaxing assumptions of symmetry and involves a detonation born near the stellar surface. The explosion begins with an essentially central ignition of a deflagration that results in the formation of a buoyancy-driven bubble of hot material that reaches the stellar surface at supersonic speeds. The bubble breakout laterally accelerates fuel-rich outer stellar layers. This material, confined by gravity to the white dwarf, races along the stellar surface and is focused at the location opposite to the point of the bubble breakout. These streams of nuclear fuel carry enough mass and energy to trigger a detonation just above the stellar surface that will incinerate the white dwarf and result in an energetic explosion. The stellar expansion following the deflagration redistributes mass in a way that ensures production of intermediate-mass and iron group elements with ejecta having a strongly layered structure and a mild amount of asymmetry following from the early deflagration phase. This asymmetry, combined with the amount of stellar expansion determined by details of the evolution (principally the energetics of deflagration, timing of detonation, and structure of the progenitor), can be expected to create a family of mildly diverse Type Ia supernova explosions.
T. Plewa; A. C. Calder; D. Q. Lamb
The distant type Ia supernova rate
We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample,which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.
Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R.S.; Aldering, G.; Astier, P.; Deustua, S.E.; Fruchter, A.S.; Goldhaber, G.; Goobar, A.; Groom, D.E.; Hardin, D.; Hook, I.M.; Howell, D.A.; Irwin, M.J.; Kim, A.G.; Kim, M.Y.; Knop, R.A.; Lee, J.C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N.A.
The Distant Type Ia Supernova Rate
DOE R&D Accomplishments (OSTI)
We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.
Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R. S.; Aldering, G.; Astier, P.; Deustua, S. E.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M. J.; Kim, A. G.; Kim, M. Y.; Knop, R. A.; Lee, J. C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N. A.
Mechanism and kinetics of carbide dissolution in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy
The present work evaluates the influence of bulk carbon content and aging temperature on the stability of carbide in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy. The carbide particles were formed during heat treatment in the {beta} phase field and preserved by water quenching. Subsequent aging treatments at 750-850 Degree-Sign C caused partial dissolution of these precipitates, as a result of the peritectoid reaction between the {beta} phase and carbide. The models based on interface reaction controlled dissolution, via uniform atomic detachment, dislocation mechanism or vacancy flow, yielded experimental predictions comparable to the observed dissolution kinetics. Furnace cooling after heat treatment in the {beta} phase field dissolved carbide particles completely, and the microstructure changed from acicular-like or block {alpha} to equiaxed {alpha} with increase of carbon content. - Highlights: Black-Right-Pointing-Pointer Carbide dissolution occurs at precipitate/matrix interfaces, forming {beta}-depleted zone. Black-Right-Pointing-Pointer Peritectoid reaction is responsible for drastic reduction of carbide volume fraction. Black-Right-Pointing-Pointer Slower dissolution rate is accounted by dislocation, vacancy flow, and curvature. Black-Right-Pointing-Pointer Lamellar changed to equiaxed {alpha} with increasing carbon from {beta} furnace cooling.
Zhang, S.Z., E-mail: email@example.com [School of Environmental and Materials Engineering, Yantai University, 32 Qingquan Road, Yantai 264005 (China); Li, M.M. [School of Environmental and Materials Engineering, Yantai University, 32 Qingquan Road, Yantai 264005 (China); Yang, R. [Titanium Alloy Laboratory, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)
Additively manufactured 3D porous Ti-6Al-4V constructs mimic trabecular bone structure and regulate osteoblast proliferation, differentiation and local factor production in a porosity and surface roughness dependent manner
Science Journals Connector (OSTI)
Additive manufacturing by laser sintering is able to produce high resolution metal constructs for orthopedic and dental implants. In this study, we used a human trabecular bone template to design and manufacture Ti-6Al-4V constructs with varying porosity via laser sintering. Characterization of constructs revealed interconnected porosities ranging from 15¢70% with compressive moduli of 2579¢3693 MPa. These constructs with macro porosity were further surface-treated to create a desirable multi-scale micro-/nano-roughness, which has been shown to enhance the osseointegration process. Osteoblasts (MG63 cells) exhibited high viability when grown on the constructs. Proliferation (DNA) and alkaline phosphatase specific activity, an early differentiation marker, decreased as porosity increased, while osteocalcin, a late differentiation marker, as well as osteoprotegerin, vascular endothelial growth factor and bone morphogenetic proteins 2 and 4 increased with increasing porosity. Three-dimensional (3D) constructs with the highest porosity and surface modification supported the greatest osteoblast differentiation and local factor production. These results indicate that additively manufactured 3D porous constructs mimicking human trabecular bone and produced with additional surface treatment can be customized for increased osteoblast response. Increased factors for osteoblast maturation and differentiation on high porosity constructs suggest the enhanced performance of these surfaces for increasing osseointegration in vivo.
Alice Cheng; Aiza Humayun; David J Cohen; Barbara D Boyan; Zvi Schwartz
Intermediate-band Photometry of Type Ia Supernovae
We present optical light curves of five Type Ia supernovae (2002er, 2002fk, 2003cg, 2003du, 2003fk). The photometric observations were performed in a set of intermediate-band filters. SNe 2002er, 2003du appear to be normal SN Ia events with similar light curve shapes, while SN 2003kf shows the behavior of a brighter SN Ia with slower decline rate after maximum. The light curves of SN 2003cg is unusual; they show a fast rise and dramatic decline near maximum and do not display secondary peak at longer wavelengths during 15-30 days after maximum light. This suggests that SN 2003cg is likely to be an intrinsically subluminous, 91bg-like SN Ia. Exploration of SN Ia feature lines through intermediate-band photometry is briefly discussed.
Wang, X; Zhang, T; Li, Z; Wang, Xiaofeng; Zhou, Xu; Zhang, Tianmeng; Li, Zongwei
Visualizing Type Ia Supernova Explosions at NERSC
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Supernova Explosions Supernova Explosions Visualizing Type Ia Supernova Explosions Childs1a-Supernovasm.png Deep inside a dying star in a galaxy far, far away, a carbon fusion flame ignites. Ignition may happen in the middle or displaced slightly to one side, but this simulation explores the consequences of central ignition. In a localized hot spot, represented here by a deformed sphere with an average radius of 100 km, carbon is assumed to have already fused to iron, producing hot ash (~10 billion K) with a density about 20% less than its surroundings. As the burning progresses, this hot buoyant ash rises up and interacts with cold fuel. Rayleigh-Taylor fingers give rise to shear and turbulence, which interacts with the flame, causing it to move faster. In about 2 seconds, the energy released blows the entire white dwarf star up,
Structure, magnetic properties and magnetoelastic anisotropy in epitaxial Sr(Ti???Co?)O? films
We report the structure, magnetic properties and magnetoelastic anisotropy of epitaxial Sr(Ti???Co?)O? films grown on LaAlO? (001) and SrTiO? (001) substrates by pulsed laser deposition. Room temperature ferromagnetism was ...
Bi, Lei
NLE Websites -- All DOE Office Websites (Extended Search)
Ti Plasmid Ti Plasmid Name: Dixenia Location: N/A Country: N/A Date: N/A Question: What can you tell me about the Ti Plasmid? Replies: This plasmid is named for a plasmid found in a bacteria called Agrobacter tumefaciens. It causes "plant cancer" or what are known as galls. They are little tumors in which the bacteria can grow and live in the plant. Ti stands for tumor inducing. The bacterium gets into the plant through some kind of wound, ie. a scratch. It injects its plasmid into a plant cell and the plasmid inserts its DNA into the plant's DNA. Then the DNA directs the plant to make a hollow tumor where the bacteria can live. Scientists have taken advantage of this plant's ability to insert foreign DNA into a plant. They take the genes out of the plasmid that cause galls, and insert genes of interest, ie. genes for pest resistance and let the plasmid carry those genes into the plant. The plant will start making the product you want. You may have seen a picture of a tobacco plant glowing because firefly genes for glowing were inserted into the plant. They did this so they could know if the gene had made it into the plant. Once they are sure the gene they want has made it into the plant, they clone the plant cells. By the way, plant tissue culture is a procedure that is very common and has been done for years, this is not the same as cloning animals.
DOE - Office of Legacy Management -- Iowa Army Ammunition Plant - IA 02
Office of Legacy Management (LM)
Army Ammunition Plant - IA 02 Army Ammunition Plant - IA 02 FUSRAP Considered Sites Iowa Army Ammunition Plant, IA Alternate Name(s): Burlington Ordnance Plant Iowa Ordnance Plant Silas Mason Company IA.02-3 Location: Located in Township 70 North, Range 3 West, Section 32, 5th Principal Meridian, Des Moines County, Burlington, Iowa IA.02-1 IA.02-5 Historical Operations: Assembled nuclear weapons, primarily high explosive components and conducted explosives testing using the high explosive components and depleted uranium. AEC and ERDA operations conducted under permit from the Department of the Army. IA.02-3 IA.02-4 Eligibility Determination: Eligible IA.02-5 Radiological Survey(s): Assessment Survey IA.02-2 Site Status: Cleanup pending by U.S. Army Corps of Engineers. IA.02-6
Prediction of flow stress in a wide temperature range involving phase transformation for as-cast Ti¢6Al¢2Zr¢1Mo¢1V alloy by artificial neural network
Science Journals Connector (OSTI)
The isothermal compressions of as-cast Ti¢6Al¢2Zr¢1Mo¢1V titanium alloy in a wide temperature range of 1073¢1323ĀK and strain rate range of 0.01¢10Ās?1 with a reduction of 60% were conducted on a Gleeble-1500 thermo-mechanical simulator. The flow stress shows a complex non-linear intrinsic relationship with strain, strain rate and temperature, meanwhile the strain-softening behavior articulates dynamic recrystallization mechanism in ? phase, dynamic recovery mechanism in ? phase and their comprehensive function during phase transformation (?Ā+Ā?). Based on the experimental data, an artificial neural network (ANN) was trained with standard back-propagation learning algorithm to generalize the complex deformation behavior characteristics. In the present ANN model, strain and temperature were taken as inputs, and flow stress as output. A comparative study has been made on ANN model and improved Arrhenius-type constitutive model, and their predictability has been evaluated in terms of correlation coefficient (R) and average absolute relative error (ARRE). During ?, ?Ā+Ā? and ? phase regime, R-value and ARRE-value for the improved Arrhenius-type model are 0.9824% and 6.02%, 0.9644% and 21.02%, and 0.9627% and 12.38%, respectively, while the R-value and ARRE-value for the ANN model are 0.9992% and 0.91%, 0.9996% and 1.47%, and 0.9975% and 2.17%, respectively. The predicted strain¢stress curves outside of experimental conditions articulate the similar intrinsic relationships with experimental strain¢stress curves. The results show that the feed-forward back-propagation ANN model can accurately tracks the experimental data in a wide temperature range and strain rate range associated with interconnecting metallurgical phenomena, and in further it has a good capacity to model complex hot deformation behavior of titanium alloy outside of experimental conditions.
Guo-zheng Quan; Wen-quan Lv; Yuan-ping Mao; Yan-wei Zhang; Jie Zhou
Gasoline and Diesel Fuel Update (EIA)
accomplishments accomplishments are impressive in themselves, and associ- ated with each milestone is the expansion of future produc- tion opportunities as another technical barrier is overcome. The extension of recovery opportunities into deep water has established the deep offshore as an area of considerable national significance. A second source of increased supply is gas from coalbed formations. Natural gas production from coalbed methane fields continued to grow in 1996 as projects initiated mainly in the early to mid 1990's matured through the dewatering phase into higher rates of gas production. Coalbed forma- tions contribute almost 1 trillion cubic feet, roughly 5 per- cent, to total U.S. production. Continued production growth from coalbeds is not likely in light of the precipitous drop in new wells completed in coalbed formations since the termination of the production tax
UMore Ph IA CR Report 7-8-10.pdf
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
PHASE IA ARCHAEOLOGICAL AND PHASE IA ARCHAEOLOGICAL AND ARCHITECTURAL HISTORY SURVEY FOR THE UMORE PARK RESEARCH WIND TURBINE PROJECT, DAKOTA COUNTY, MINNESOTA SHPO File No. Pending Client No. Pending The 106 Group Project No. 10-18 Submitted to: Barr Engineering Company 4700 West 77th Street Minneapolis, MN 55435-4803 Submitted by: The 106 Group Ltd. The Dacotah Building 370 Selby Avenue St. Paul, MN 55102 Principal Investigators: AnneKetz, M.A., RPA Greg Mathis, M.C.R.P. Report Authors: Mark Doperalski, B.S. Miranda Van Vleet, M.H.P July 2010 UMore Park Wind Turbine Project Phase IA Archaeological and Architectural History Survey Page i MANAGEMENT SUMMARY During May of 2010, The 106 Group Ltd. (106 Group) conducted a Phase IA archaeological and architectural history survey for the University of Minnesota Outreach, Research, and
CIRCUMSTELLAR ABSORPTION IN DOUBLE DETONATION TYPE Ia SUPERNOVAE
Upon formation, degenerate He core white dwarfs are surrounded by a radiative H-rich layer primarily supported by ideal gas pressure. In this Letter, we examine the effect of this H-rich layer on mass transfer in He+C/O double white dwarf binaries that will eventually merge and possibly yield a Type Ia supernova (SN Ia) in the double detonation scenario. Because its thermal profile and equation of state differ from the underlying He core, the H-rich layer is transferred stably onto the C/O white dwarf prior to the He core's tidal disruption. We find that this material is ejected from the binary system and sweeps up the surrounding interstellar medium hundreds to thousands of years before the SN Ia. The close match between the resulting circumstellar medium profiles and values inferred from recent observations of circumstellar absorption in SNe Ia gives further credence to the resurgent double detonation scenario.
Shen, Ken J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Guillochon, James [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Foley, Ryan J., E-mail: firstname.lastname@example.com [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Abstract IA14: Functional genomics and cancer vulnerabilities
Science Journals Connector (OSTI)
...Cancer Research. November 2014 meeting-abstract Genomics Genomics: Oral Presentations - Invited Abstracts Abstracts...2013; San Diego, CA Abstract IA14: Functional genomics and cancer vulnerabilities William C. Hahn Dana-Farber...
William C. Hahn
EARLY EMISSION FROM TYPE Ia SUPERNOVAE
A unique feature of deflagration-to-detonation (DDT) white dwarf explosion models of supernovae of type Ia is the presence of a strong shock wave propagating through the outer envelope. We consider the early emission expected in such models, which is produced by the expanding shock-heated outer part of the ejecta and precedes the emission driven by radioactive decay. We expand on earlier analyses by considering the modification of the pre-detonation density profile by the weak shocks generated during the deflagration phase, the time evolution of the opacity, and the deviation of the post-shock equation of state from that obtained for radiation pressure domination. A simple analytic model is presented and shown to provide an acceptable approximation to the results of one-dimensional numerical DDT simulations. Our analysis predicts a {approx}10{sup 3} s long UV/optical flash with a luminosity of {approx}1 to {approx}3 Multiplication-Sign 10{sup 39} erg s{sup -1}. Lower luminosity corresponds to faster (turbulent) deflagration velocity. The luminosity of the UV flash is predicted to be strongly suppressed at t > t{sub drop} {approx} 1 hr due to the deviation from pure radiation domination.
Rabinak, Itay; Waxman, Eli [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Livne, Eli, E-mail: email@example.com [Racah Institute of Physics, Hebrew University, Jerusalem (Israel)
The 1.05-?m feature in the spectrum of the Type Ia supernova 1994D: He in SNe Ia?
Science Journals Connector (OSTI)
......SNe Ia). Although the agreed basic scenario is thermonuclear fusion within a white dwarf (WD), the process leading...a pressure wave into the WD which then triggers thermonuclear fusion in the core. In this scenario, explosion can......
P. A. Mazzali; L. B. Lucy
Exploration of R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd2AlGe2 and Analysis of the U3Si2 and Zr3Al2 Structure Types
In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} several new compounds were synthesized with different crystal structures, but similar structural features. In Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} can be thought of as being formed from two 3{sup 2}434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd{sub 2}MgGe{sub 2} and Gd{sub 2}InGe{sub 2} both possess the same 3{sup 2}434 nets of Gd atoms as Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, but these nets are connected differently, forming the Mo{sub 2}FeB{sub 2} crystal structure. A search of the literature revealed that compounds with the composition R{sub 2}XM{sub 2} (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo{sub 2}FeB{sub 2}, Zr{sub 3}Al{sub 2}, Mn{sub 2}AlB{sub 2} and W{sub 2}CoB{sub 2} crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd{sub 2}AlGe{sub 2} forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how electrons can be accounted for. A series of electronic structure calculations were performed on models with the U{sub 3}Si{sub 2} and Zr{sub 3}Al{sub 2} structures, using Zr and A1 as the building blocks. The starting point for these models was the U{sub 3}Si{sub 2} structure, and models were created to simulate the transition from the idealized U{sub 3}Si{sub 2} structure to the distorted Zr{sub 3}Al{sub 2} structure. Analysis of the band structures of the models has shown that the transition from the U{sub 3}Si{sub 2} structure to the Zr{sub 3}Al{sub 2} structure lifts degeneracies along the {Lambda} {yields} Z direction, indicating a Peierls-type mechanism for the displacement occurring in the positions of the Zr atoms.
Sean William McWhorter
Simulations of Turbulent Thermonuclear Burning in Type Ia Supernovae
Type Ia supernovae have recently received considerable attention because it appears that they can be used as "standard candles" to measure cosmic distances out to billions of light years away from us. Observations of type Ia supernovae seem to indicate that we are living in a universe that started to accelerate its expansion when it was about half its present age. These conclusions rest primarily on phenomenological models which, however, lack proper theoretical understanding, mainly because the explosion process, initiated by thermonuclear fusion of carbon and oxygen into heavier elements, is difficult to simulate even on supercomputers. Here, we investigate a new way of modeling turbulent thermonuclear deflagration fronts in white dwarfs undergoing a type Ia supernova explosion. Our approach is based on a level set method which treats the front as a mathematical discontinuity and allows for full coupling between the front geometry and the flow field. New results of the method applied to the problem of type Ia supernovae are obtained. It is shown that in 2-D with high spatial resolution and a physically motivated subgrid scale model for the nuclear flames numerically "converged" results can be obtained, but for most initial conditions the stars do not explode. In contrast, simulations in 3-D, do give the desired explosions and many of their properties, such as the explosion energies, lightcurves and nucleosynthesis products, are in very good agreement with observed type Ia supernovae.
W. Hillebrandt; M. Reinecke; W. Schmidt; F. K. Roepke; C. Travaglio; J. C. Niemeyer
Instability, intermixing and electronic structure at theepitaxialLaAl...
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intermixing and electronic structure at the epitaxialLaAlO3SrTiO3(001) heterojunction. Instability, intermixing and electronic structure at the epitaxialLaAlO3...
Type Ia Supernovae Yielding Distances with 3-4% Precision
The luminosities of Type Ia supernovae (SN), the thermonuclear explosions of white dwarf stars, vary systematically with their intrinsic color and light-curve decline rate. These relationships have been used to calibrate their luminosities to within ~0.14-0.20 mag from broadband optical light curves, yielding individual distances accurate to ~7-10%. Here we identify a subset of SN Ia that erupt in environments having high ultraviolet surface brightness and star-formation surface density. When we apply a steep model extinction law, these SN can be calibrated to within ~0.065-0.075 mag, corresponding to ~3-4% in distance -- the best yet with SN Ia by a substantial margin. The small scatter suggests that variations in only one or two progenitor properties account for their light-curve-width/color/luminosity relation.
Kelly, Patrick L; Burke, David L; Hicken, Malcolm; Ganeshalingam, Mohan; Zheng, Weikang
Signatures of A Companion Star in Type Ia Supernovae
While type Ia Supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is if there is a non-degenerate companion star at the time of a thermonuclear explosion of a white dwarf (WD). In this paper, we investigate if an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multi-dimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, while the predicted behaviors (redder and fainter for the companion direction) are opposite to what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from observationally derived, thus a large sample of SNe Ia...
Maeda, Keiichi; Shigeyama, Toshikazu
Double degenerates and progenitors of supernovae type Ia
We report on systematic radial velocity surveys for white dwarf - white dwarf binaries (double degenerates - DDs) including SPY (ESO Supernovae Ia progenitor survey) recently carried out at the VLT. A large sample of DD will allow us to put strong constrains on the phases of close binary evolution of the progenitor systems and to perform an observational test of the DD scenario for supernovae of type Ia. We explain how parameters of the binaries can be derived from various methods. Results for a sample of DDs are presented and discussed.
R. Napiwotzki; L. Yungelson; G. Nelemans; T. R. Marsh; B. Leibundgut; A. Renzini; D. Homaier; D. Koester; S. Moehler; N. Christlieb; D. Reimers; H. Drechsel; U. Heber; C. Karl; E. -M. Pauli
The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refrigeration. We also present the current status of fabrication and testing.
Zbasnik, J.; Wang, S.T.; Chen, J.Y.; DeVries, G.J.; DeMarco, R.; Fahmie, M.; Geyer, A.; Green, M.A.; Harkins, J.; Henderson, T.; Hinkson, J.; Hoyer, E.H.; Krupnick, J.; Marks, S.; Ottens, F.; Paterson, J.A.; Pipersky, P.; Portmann, G.; Robin, D.A.; Schlueter, R.D.; Steier, C.; Taylor, C.E.; Wahrer, R.
Search for double degenerate progenitors of supernovae type Ia with SPY
We report on a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY).
R. Napiwotzki; H. Drechsel; U. Heber; C. Karl; E. -M. Pauli; N. Christlieb; H. -J. Hagen; D. Reimers; D. Koester; S. Moehler; D. Homeier; B. Leibundgut; A. Renzini; T. R. Marsh; G. Nelemans; L. Yungelson
Spectral Observations and Analyses of Low-Redshift Type Ia Supernovae
1.3.2 Thermonuclear Supernovae . . . . . . . . 1.4 Why WriteIa are the result of thermonuclear explosions of C/O whiteIa are the result of thermonuclear explosions of C/O white
Silverman, Jeffrey Michael
Berkeley Supernova Ia Program ¢ V. Late-time spectra of Type Ia Supernovae
Science Journals Connector (OSTI)
......normal-velocity objects, the red points HV objects and the black...A. Diamond-Stanic, E. Gates, K. Hiner, M. Kandrashoff...2004) 128:387. Hicken M. , Wood-Vasey W. M., Blondin S...al. ApJ (2009) 699:L139. Wood-Vasey W. M. , et al. ApJ......
Jeffrey M. Silverman; Mohan Ganeshalingam; Alexei V. Filippenko
INDECOMPOSABLE RACKS OF ORDER p 2 MAT IAS GRA
INDECOMPOSABLE RACKS OF ORDER p 2 MAT Ō?? IAS GRA Ō?Ø NA Abstract. We classify indecomposable racks order is trivial. 1. Introduction Racks and quandles have been considered by G. Wraith and J. Conway categories, one is immediately led to the notion of a rack. On the other hand, in [ESS, EGS, S] and [LYZ1
Gra├▒a, Mat├Łas
INCOMPLETE CARBON-OXYGEN DETONATION IN TYPE Ia SUPERNOVAE
Incomplete carbon-oxygen detonation with reactions terminating after burning of C{sup 12} in the leading C{sup 12} + C{sup 12} reaction (C-detonation) may occur in the low-density outer layers of white dwarfs exploding as Type Ia supernovae (SNe Ia). Previous studies of carbon-oxygen detonation structure and stability at low densities were performed under the assumption that the velocity of a detonation wave is derived from complete burning of carbon and oxygen to iron. In fact, at densities {rho} {<=} 10{sup 6} g cm{sup -3} the detonation in SNe Ia may release less than a half of the available nuclear energy. In this paper, we study basic properties of such detonations. We find that the length of an unsupported steady-state C-detonation is {approx_equal}30-100 times greater than previously estimated and that the decreased energy has a drastic effect on the detonation stability. In contrast to complete detonations which are one-dimensionally stable, C-detonations may be one-dimensionally unstable and propagate by periodically re-igniting themselves via spontaneous burning. The re-ignition period at {rho} {<=} 10{sup 6} g cm{sup -3} is estimated to be greater than the timescale of an SN Ia explosion. This suggests that propagation and quenching of C-detonations at these densities could be affected by the instability. Potential observational implications of this effect are discussed.
Dominguez, Inma [Departamento de Fisica Teorica y del Cosmos, University of Granada, 18071 Granada (Spain); Khokhlov, Alexei [Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)
The EqIA Publishing Template Impact Assessment Summary
The EqIA Publishing Template Impact Assessment Summary 1. Name of policy, function or service. Bedgebury 5 year strategy and development plan. This is a partial assessment. 2. Purpose and aims with ETWF: Sustainable Resource, Climate Change, Natural Environment, Quality of Life, Business and Markets
HOSPITALITY AND TOURISM MANAGEMENT MAJOR Virgu1iaTech
Hospitality Facilities Planning and Methods I (3) Management (3) #HTM 3484 Socio-Cultural Impacts of Tourism 4414 Food and Beverage Management (Pre: HTM 3414) * #HTM 4464 Human Resources Management in HospHOSPITALITY AND TOURISM MANAGEMENT MAJOR Virgu1iaTech Panplil College of BusIness Department
Virginia Tech
Circumstellar interaction of the type Ia supernova 2002ic
Science Journals Connector (OSTI)
......with arguments in favour of a high-energy SN Ia event in this case, raises...WD explosion with a high kinetic energy of ejecta. The SN 1.5 origin of...2002ic-like events requires an accurate energy audit, for which the direct detection......
N. N. Chugai; R. A. Chevalier; P. Lundqvist
Thermonuclear supernova models, and observations of Type Ia supernovae
In this paper, we review the present state of theoretical models of thermonuclear supernovae, and compare their predicitions with the constraints derived from observations of Type Ia supernovae. The diversity of explosion mechanisms usually found in one-dimensional simulations is a direct consequence of the impossibility to resolve the flame structure under the assumption of spherical symmetry. Spherically symmetric models have been successful in explaining many of the observational features of Type Ia supernovae, but they rely on two kinds of empirical models: one that describes the behaviour of the flame on the scales unresolved by the code, and another that takes account of the evolution of the flame shape. In contrast, three-dimensional simulations are able to compute the flame shape in a self-consistent way, but they still need a model for the propagation of the flame in the scales unresolved by the code. Furthermore, in three dimensions the number of degrees of freedom of the initial configuration of the white dwarf at runaway is much larger than in one dimension. Recent simulations have shown that the sensitivity of the explosion output to the initial conditions can be extremely large. New paradigms of thermonuclear supernovae have emerged from this situation, as the Pulsating Reverse Detonation. The resolution of all these issues must rely on the predictions of observational properties of the models, and their comparison with current Type Ia supernova data, including X-ray spectra of Type Ia supernova remnants.
E. Bravo; C. Badenes; D. Garcia-Senz
Constraining the dark energy and smoothness parameter with typeĀIa supernovae and gamma-ray bursts
Science Journals Connector (OSTI)
The existence of inhomogeneities in the observed Universe modifies the distance-redshift relations thereby affecting the results of cosmological tests in comparison to the ones derived assuming spatially uniform models. By modeling the inhomogeneities through a Zeldovich-Kantowski-Dyer-Roeder approach which is phenomenologically characterized by a smoothness parameter ?, we rediscuss the constraints on the cosmic parameters based on typeĀIa supernovae (SNeĀIa) and gamma-ray bursts (GRBs) data. The present analysis is restricted to a flat ?CDM model with the reasonable assumption that ? does not clump. A ?2 analysis using 557 SNeĀIa data from the Union2 compilation data (R. Amanullah et al., Astrophys. J. 716, 712 (2010).) constrains the pair of parameters (?m, ?) to ?m=0.27-0.03+0.08 (2?) and ??0.25. A similar analysis based only on 59 Hymnium GRBs (H. Wei, J. Cosmol. Astropart. Phys. 08 (2010) 020.) constrains the matter density parameter to be ?m=0.35-0.24+0.62 (2?) while all values for the smoothness parameter are allowed. By performing a joint analysis, it is found that ?m=0.27-0.03+0.06 and ??0.52. As a general result, although considering that current GRB data alone cannot constrain the smoothness ? parameter, our analysis provides an interesting cosmological probe for dark energy even in the presence of inhomogeneities.
V. C. Busti; R. C. Santos; J. A. S. Lima
Incompatibility of a comoving Ly-alpha forest with supernova-Ia luminosity distances
Recently Perlmutter et al. suggested a positive value of Einstein's cosmological constant Lambda on the basis of luminosity distances from type-Ia supernovae. However, Lambda world models had earlier been proposed by Hoell & Priester and Liebscher et al. on the basis of quasar absorption-line data. Employing more general repulsive fluids ("dark energy") encompassing the Lambda component we quantitatively compare both approaches with each other. Fitting the SN-data by a minimum-component model consisting of dark energy + dust yields a closed universe with a large amount of dust exceeding the baryonic content constrained by big-bang nucleosynthesis. The nature of the dark energy is hardly constrained. Only when enforcing a flat universe there is a clear tendency to a dark-energy Lambda fluid and the `canonical' value Omega_M = 0.3 for dust. Conversely, fitting the quasar-data by a minimum-component model yields a sharply defined, slightly closed model with a low dust density ruling out significant pressureless dark matter. The dark-energy component obtains an equation-of-state P = -0.96 epsilon close to that of a Lambda-fluid. Omega_M = 0.3 or a precisely flat spatial geometry are inconsistent with minimum-component models. It is found that quasar and supernova data sets cannot be reconciled with each other via (repulsive ideal fluid+dust+radiation)-world models. Compatibility could be reached by drastic expansion of the parameter space with at least two exotic fluids added to dust and radiation as world constituents. If considering such solutions as far-fetched one has to conclude that the quasar absorption line and the SN-Ia constraints are incompatible.
Jens Thomas; Hartmut Schulz
Deformation mechanisms in TiAl/Ti{sub 3}Al structures
The deformation behavior of two-phase titanium aluminide alloys with different microstructures has been investigated in a wide temperature range using deformation tests and electron microscope observations. The structure of lamellar interfaces was characterized with respect to their role as dislocation sources. Thermally activated processes governing the dislocation mobility were characterized in terms of activation volumes and activation energies. The analysis is aimed at the identification of the dislocation processes operating under deformation conditions which are relevant for practical applications.
Appel, F.; Wagner, R. [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research
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Thermonuclear .Ia Supernovae from Helium Shell Detonations: Explosion Models and Observables
Science Journals Connector (OSTI)
During the early evolution of an AM Canum Venaticorum system, helium is accreted onto the surface of a white dwarf under conditions suitable for unstable thermonuclear ignition. The turbulent motions induced by the convective burning phase in the He envelope become strong enough to influence the propagation of burning fronts and may result in the onset of a detonation. Such an outcome would yield radioactive isotopes and a faint rapidly rising thermonuclear ".Ia" supernova. In this paper, we present hydrodynamic explosion models and observable outcomes of these He shell detonations for a range of initial core and envelope masses. The peak UVOIR bolometric luminosities range by a factor of 10 (from 5 ? 1041 to 5 ? 1042 erg s¢1), and the R-band peak varies from M R,peak = ¢15 to ¢18. The rise times in all bands are very rapid (40Ca through 56Ni) and unburnt He. Thus, the spectra around peak light lack signs of intermediate-mass elements and are dominated by CaĀII and TiĀII features, with the caveat that our radiative transfer code does not include the nonthermal effects necessary to produce He features.
Ken J. Shen; Dan Kasen; Nevin N. Weinberg; Lars Bildsten; Evan Scannapieco
An Analysis of Department of Defense Instruction 8500.2 'Information Assurance (IA) Implementation.'
The Department of Defense (DoD) provides its standard for information assurance in its Instruction 8500.2, dated February 6, 2003. This Instruction lists 157 'IA Controls' for nine 'baseline IA levels.' Aside from distinguishing IA Controls that call for elevated levels of 'robustness' and grouping the IA Controls into eight 'subject areas' 8500.2 does not examine the nature of this set of controls, determining, for example, which controls do not vary in robustness, how this set of controls compares with other such sets, or even which controls are required for all nine baseline IA levels. This report analyzes (1) the IA Controls, (2) the subject areas, and (3) the Baseline IA levels. For example, this report notes that there are only 109 core IA Controls (which this report refers to as 'ICGs'), that 43 of these core IA Controls apply without variation to all nine baseline IA levels and that an additional 31 apply with variations. This report maps the IA Controls of 8500.2 to the controls in NIST 800-53 and ITGI's CoBIT. The result of this analysis and mapping, as shown in this report, serves as a companion to 8500.2. (An electronic spreadsheet accompanies this report.)
Campbell, Philip LaRoche
Phase equilibria, formation, crystal and electronic structure of ternary compounds in Ti-Ni-Sn and Ti-Ni-Sb ternary systems
The phase equilibria of the Ti-Ni-Sn and Ti-Ni-Sb ternary systems have been studied in the whole concentration range by means of X-ray and EPM analyses at 1073 K and 873 K, respectively. Four ternary intermetallic compounds TiNiSn (MgAgAs-type), TiNi{sub 2-x}Sn (MnCu{sub 2}Al-type), Ti{sub 2}Ni{sub 2}Sn (U{sub 2}Pt{sub 2}Sn-type), and Ti{sub 5}NiSn{sub 3} (Hf{sub 5}CuSn{sub 3}-type) are formed in Ti-Ni-Sn system at 1073 K. The TiNi{sub 2}Sn stannide is characterized by homogeneity in the range of 50-47 at% of Ni. The Ti-Ni-Sb ternary system at 873 K is characterized by formation of three ternary intermetallic compounds, Ti{sub 0.8}NiSb (MgAgAs-type), Ti{sub 5}Ni{sub 0.45}Sb{sub 2.55} (W{sub 5}Si{sub 3}-type), and Ti{sub 5}NiSb{sub 3} (Hf{sub 5}CuSn{sub 3}-type). The solubility of Ni in Ti{sub 0.8}NiSb decreases number of vacancies in Ti site up to Ti{sub 0.91}Ni{sub 1.1}Sb composition. - Graphical abstract: Isothermal section of the Ti-Ni-Sn phase diagram and DOS distribution in hypothetical TiNi{sub 1+x}Sn solid solution. Highlights: Black-Right-Pointing-Pointer Ti-Ni-Sn phase diagram was constructed at 1073 K. Black-Right-Pointing-Pointer Four ternary compounds are formed: TiNiSn, TiNi{sub 2-x}Sn, Ti{sub 2}Ni{sub 2}Sn, and Ti{sub 5}NiSn{sub 3}. Black-Right-Pointing-Pointer Three ternary compounds exist in Ti-Ni-Sb system at 873 K. Black-Right-Pointing-Pointer The TiNi{sub 2}Sb compound is absent.
Romaka, V.V., E-mail: firstname.lastname@example.com [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Rogl, P. [Institut fur Physikalische Chemie der Universitat Wien, Wahringerstrabe 42, A-1090 Wien (Austria); Romaka, L.; Stadnyk, Yu. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Melnychenko, N.; Grytsiv, A.; Falmbigl, M. [Institut fur Physikalische Chemie der Universitat Wien, Wahringerstrabe 42, A-1090 Wien (Austria); Skryabina, N. [Perm State University, Bukireva Str. 15, 614990 Perm (Russian Federation)
Learning from the scatter in type Ia supernovae
Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional scatter is caused by gravitational magnification by large scale structure. Here we probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, {sigma}{sub 8}, is contained in the scatter. In principle, it will be possible to constrain {sigma}{sub 8} to within 5% with observations of 2000 Type Ia Supernovae. We identify three sources of systematic error - evolution of intrinsic scatter, baryon contributions to lensing, and non-Gaussianity of lensing - which will make this measurement difficult.
Dodelson, Scott [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States); Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637-1433 (United States); Vallinotto, Alberto [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States); Department of Physics, The University of Chicago, Chicago, Illinois 60637-1433 (United States)
RADIOACTIVELY POWERED RISING LIGHT CURVES OF TYPE Ia SUPERNOVAE
The rising luminosity of the recent, nearby supernova 2011fe shows a quadratic dependence with time during the first Almost-Equal-To 0.5-4 days. In addition, studies of the composite light curves formed from stacking together many Type Ia supernovae (SNe Ia) have found similar power-law indices for the rise, but may also show some dispersion that may indicate diversity. I explore what range of power-law rises are possible due to the presence of radioactive material near the surface of the exploding white dwarf (WD). I summarize what constraints such a model places on the structure of the progenitor and the distribution and velocity of ejecta. My main conclusion is that for the inferred explosion time for SN 2011fe, its rise requires an increasing mass fraction X {sub 56} Almost-Equal-To (4-6) Multiplication-Sign 10{sup -2} of {sup 56}Ni distributed between a depth of Almost-Equal-To 10{sup -2} and 0.3 M {sub Sun} below the WD's surface. Radioactive elements this shallow are not found in simulations of a single C/O detonation. Scenarios that may produce this material include helium-shell burning during a double-detonation ignition, a gravitationally confined detonation, and a subset of deflagration to detonation transition models. In general, the power-law rise can differ from quadratic depending on the details of the velocity, density, and radioactive deposition gradients in a given event. Therefore, comparisons of this work with observed bolometric rises of SNe Ia would place strong constraints on the properties of the shallow outer layers, providing important clues for identifying the elusive progenitors of SNe Ia.
Piro, Anthony L., E-mail: email@example.com [Theoretical Astrophysics, California Institute of Technology, 1200 East California Boulevard, M/C 350-17, Pasadena, CA 91125 (United States)
LATE-TIME SPECTRAL OBSERVATIONS OF THE STRONGLY INTERACTING TYPE Ia SUPERNOVA PTF11kx
PTF11kx was a Type Ia supernova (SN Ia) that showed time-variable absorption features, including saturated Ca II H and K lines that weakened and eventually went into emission. The strength of the emission component of H{alpha} gradually increased, implying that the SN was undergoing significant interaction with its circumstellar medium (CSM). These features, and many others, were blueshifted slightly and showed a P-Cygni profile, likely indicating that the CSM was directly related to, and probably previously ejected by, the progenitor system itself. These and other observations led Dilday et al. to conclude that PTF11kx came from a symbiotic nova progenitor like RS Oph. In this work we extend the spectral coverage of PTF11kx to 124-680 rest-frame days past maximum brightness. The late-time spectra of PTF11kx are dominated by H{alpha} emission (with widths of full width at half-maximum intensity Almost-Equal-To 2000 km s{sup -1}), strong Ca II emission features ({approx}10,000 km s{sup -1} wide), and a blue 'quasi-continuum' due to many overlapping narrow lines of Fe II. Emission from oxygen, He I, and Balmer lines higher than H{alpha} is weak or completely absent at all epochs, leading to large observed H{alpha}/H{beta} intensity ratios. The H{alpha} emission appears to increase in strength with time for {approx}1 yr, but it subsequently decreases significantly along with the Ca II emission. Our latest spectrum also indicates the possibility of newly formed dust in the system as evidenced by a slight decrease in the red wing of H{alpha}. During the same epochs, multiple narrow emission features from the CSM temporally vary in strength. The weakening of the H{alpha} and Ca II emission at late times is possible evidence that the SN ejecta have overtaken the majority of the CSM and agrees with models of other strongly interacting SNe Ia. The varying narrow emission features, on the other hand, may indicate that the CSM is clumpy or consists of multiple thin shells.
Silverman, Jeffrey M. [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Nugent, Peter E.; Filippenko, Alexei V.; Cenko, S. Bradley [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gal-Yam, Avishay [Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Sullivan, Mark [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Pan, Yen-Chen; Hook, Isobel M., E-mail: email@example.com [Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates
We explore the sensitivity of the nucleosynthesis due to type Ia supernovae with respect to uncertainties in nuclear reaction rates. We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf, and have post-processed the thermodynamic trajectories of every mass-shell with a nucleosynthetic code, with increases (decreases) by a factor of ten on the rates of 1196 nuclear reactions. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. For selected reactions, we have recomputed the nucleosynthesis with alternative prescriptions for their rates taken from the JINA REACLIB database, and have analyzed the temperature ranges where modifications of their rates have the strongest effect on nucleosynthesis. The nucleosynthesis resulting from the Type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of 12C nuclei. The energy of the explosion changes by less than \\sim4%. The changes in the nucleosynthesis due to the modification of the rates of fusion reactions are as well quite modest, for instance no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of two. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and alphas. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the charged particle reactions, the most influential on supernova nucleosynthesis are 30Si + p \\rightleftarrows 31P + {\\gamma}, 20Ne + {\\alpha} \\rightleftarrows 24Mg + {\\gamma}, and 24Mg + {\\alpha} \\rightleftarrows 27Al + p. The temperatures at which a modification of their rate has a larger impact are in the range 2 < T < 4 GK. (abridged)
Eduardo Bravo; Gabriel MartĒnez-Pinedo
CanungraCk Darlington AL Darlington Coom era R O'Reillys AL Beechmont AL Binna Burra AL BackCk Tyungun AL Numinbah Valley AL NerangR Natural Bridge Numinbah AL Little Nerang Dam AL Albert R Bromfleet AL Benobble AL Wolffdene AL Luscombe AL Wongawallan AL Mt Tamborine Canungra Pimpama R Laheys Lookout
Greenslade, Diana
The Diversity of Variations in the Spectra of Type Ia Supernovae
for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Lifan Wang Committee Members, Nicholas Suntze George Kattawar Sean McDeavitt Head of Department, George R. Welch August 2012 Major Subject: Physics iii ABSTRACT The Diversity... of Variations in the Spectra of Type Ia Supernovae. (August 2012) Andrew James Wagers, B.A., Berea College; M.S., Stephen F. Austin State University Chair of Advisory Committee: Dr. Lifan Wang Type Ia supernovae (SNe Ia) are currently the best probe...
Wagers, Andrew James
Experto Universitario Java Enterprise 2012-2013 Depto. Ciencia de la Computacin e IA
Experto Universitario Java Enterprise ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Lenguaje Lenguaje Java Avanzado ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Lenguaje Java 2 ├Źndice. Ciencia de la Computaci├│n e IA Lenguaje Java 3 Java ┬Ę Java es un lenguaje OO creado por Sun Microsystems
Escolano, Francisco
Experto Universitario Java Enterprise 2012-2013 Depto. Ciencia de la Computacin e IA
Experto Universitario Java Enterprise ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Lenguaje Avanzado ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Depuraci├│n y logs - 2 ┬Ę El depurador de Eclipse Enterprise Lenguaje Java Avanzado ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Depuraci├│n y logs - 3 El
Escolano, Francisco
Teor'ia de Grupos y Mec'anica Qu'antica Luis A. Seco
determinado por el Hamiltoniano de la energ'ia, un operador que, actuando sobre una funci'on /(x 1 ; : : : ; xTeor'ia de Grupos y Mec'anica Qu'antica Luis A. Seco Universidad de Toronto. Notas del curso; Teor'ia de Grupos y Mec'anica Cu'antica, L. Seco. U.I.M.P. La Coru~na, 27 Junio -- 1 Julio, 1994
Seco, Luis A.
Turbulence-Flame Interactions in Type Ia Supernovae
The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to $8 \\times 10^7$ g cm$^{-3}$, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and $3 \\times 10^7$ g cm$^{-3}$ where the nature of the burning changes qualitatively. By $1 \\times 10^7$ g cm$^{-3}$, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles a laminar flame, but is turbulently broadened with an effective diffusion coefficient, $D_T \\sim u' l$, where $u'$ is the turbulent intensity and $l$ is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. Implications for a possible transition to detonation are discussed.
A. J. Aspden; J. B. Bell; M. S. Day; S. E. Woosley; M. Zingale
The Recurrent Nova U Scorpii - A Type Ia Supernova Progenitor
We derive the mass of the white dwarf in the eclipsing recurrent nova U Sco from the radial velocity semi-amplitudes of the primary and secondary stars. Our results give a high white dwarf mass of M_1 = 1.55 \\pm 0.24M_\\odot, consistent with the thermonuclear runaway model of recurrent nova outbursts. We confirm that U Sco is the best Type Ia supernova progenitor known, and predict that the time to explosion is within ~700,000 years.
T. D. Thoroughgood; V. S. Dhillon; S. P. Littlefair; T. R. Marsh; D. A. Smith
Tension in the Recent Type Ia Supernovae Datasets
In the present work, we investigate the tension in the recent Type Ia supernovae (SNIa) datasets Constitution and Union. We show that they are in tension not only with the observations of the cosmic microwave background (CMB) anisotropy and the baryon acoustic oscillations (BAO), but also with other SNIa datasets such as Davis and SNLS. Then, we find the main sources responsible for the tension. Further, we make this more robust by employing the method of random truncation. Based on the results of this work, we suggest two truncated versions of the Union and Constitution datasets, namely the UnionT and ConstitutionT SNIa samples, whose behaviors are more regular.
Hao Wei
Office of Legacy Management (LM)
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E-Print Network 3.0 - al si ca Sample Search Results
NLE Websites -- All DOE Office Websites (Extended Search)
Summary: and Gibbs 1976). 12;KROEKER ET AL.: OXYGEN-17 NMR OF GLASSY AND CRYSTALLINE TITANITE 575 CaTiSiO5 glass... ; Lee and Stebbins 2000; Zhao et al. 2000). The spectra for...
Sensitivity study of explosive nucleosynthesis in type Ia supernovae: Modification of individual thermonuclear reaction rates
Science Journals Connector (OSTI)
Background: Type Ia supernovae contribute significantly to the nucleosynthesis of many Fe-group and intermediate-mass elements. However, the robustness of nucleosynthesis obtained via models of this class of explosions has not been studied in depth until now.Purpose: We explore the sensitivity of the nucleosynthesis resulting from thermonuclear explosions of massive white dwarfs with respect to uncertainties in nuclear reaction rates. We put particular emphasis on indentifying the individual reactions rates that most strongly affect the isotopic products of these supernovae.Method: We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf and have postprocessed the thermodynamic trajectories of every mass shell with a nucleosynthetic code to obtain the chemical composition of the ejected matter. We have considered increases (decreases) by a factor of 10 on the rates of 1196 nuclear reactions (simultaneously with their inverse reactions), repeating the nucleosynthesis calculations after modification of each reaction rate pair. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. From the calculations we have selected the reactions that have the largest impact on the supernova yields, and we have computed again the nucleosynthesis using two or three alternative prescriptions for their rates, taken from the JINA REACLIB database. For the three reactions with the largest sensitivity we have analyzed as well the temperature ranges where a modification of their rates has the strongest effect on nucleosynthesis.Results: The nucleosynthesis resulting from the type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of two 12C nuclei. The energy of the explosion changes by less than ?4% when the rates of the reactions 12C+12C or 16O+16O are multiplied by a factor of ū10 or ū0.1. The changes in the nucleosynthesis owing to the modification of the rates of these fusion reactions are also quite modest; for instance, no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of 2. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and ?. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the species with yields larger than 10?8M?, 35S has the largest sensitivity to the nuclear reaction rates. It is remarkable that the reactions involving elements with Z>22 have a tiny influence on the supernova nucleosynthesis. Among the charged-particle reactions, the most influential on supernova nucleosynthesis are 30Si+p?31P+?, 20Ne+??24Mg+?, and 24Mg+??27Al+p. The temperatures at which a modification of their rate has a larger impact are in the range 2?T?4 GK.Conclusions: The explosion model (i.e., the assumed conditions and propagation of the flame) chiefly determines the element production of type Ia supernovae and derived quantities such as their luminosity, while the nuclear reaction rates used in the simulations have a small influence on the kinetic energy and final chemical composition of the ejecta. Our results show that the uncertainty in individual thermonuclear reaction rates cannot account for discrepancies of a factor of 2 between isotopic ratios in type Ia supernovae and those in the solar system, especially within the Fe group.
Eduardo Bravo and Gabriel MartĒnez-Pinedo
Developing TiAIN Coatings for Intermediate Temperature-Solid Oxide Fuel Cell Interconnect Applications
TiN-type coatings have potential to be used as SOFC interconnect coatings SOFC because of their low resistance and high temperature stability. In this research, various (Ti,Al)N coatings were deposited on stainless steels by filtered-arc method. ASR and XRD tests were conducted on these coatings, and SEM/EDAX analysis were conducted after ASR and XRD tests. SEM/EDAX analyses show that (Ti,Al)N remains stable at temperature up to 700░C. It is also indicated that Al has beneficial effect on the stability of TiN type coatings. At 900░C, (Ti-30Al)N is fully oxidized and some of (Ti-50Al)N coating still remains as nitride. The analyses on cross-sectional samples show that these coatings are effective barrier to the Cr migration. In summary, (Ti.Al)N coatings are good candidates for the SOFC interconnect applications at 700░C. The future directions of this research are to improve the stability of these coatings by alloy-doping and to develop multi-layer coatings.
Liu, X. (West Virginia University); Johnson, C.D.; Li, C. (West Virginia University); Xu, J. (West Virginia University); Cross, C.
Berkeley Supernova Ia Program ¢ I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae
Science Journals Connector (OSTI)
......Astier et al. ; Riess et al. ; Wood-Vasey et al. ; Hicken et al...with one CCD in each of the red and blue arms of the spectrograph...AJ 112 2408. 45 Hicken M. , Wood-Vasey W. M., Blondin S...A. 1994 AJ 108 2233. 118 Wood-Vasey W. M. 2007 ApJ 666......
Jeffrey M. Silverman; Ryan J. Foley; Alexei V. Filippenko; Mohan Ganeshalingam; Aaron J. Barth; Ryan Chornock; Christopher V. Griffith; Jason J. Kong; Nicholas Lee; Douglas C. Leonard; Thomas Matheson; Emily G. Miller; Thea N. Steele; Brian J. Barris; Joshua S. Bloom; Bethany E. Cobb; Alison L. Coil; Louis-Benoit Desroches; Elinor L. Gates; Luis C. Ho; Saurabh W. Jha; Michael T. Kandrashoff; Weidong Li; Kaisey S. Mandel; Maryam Modjaz; Matthew R. Moore; Robin E. Mostardi; Marina S. Papenkova; Sung Park; Daniel A. Perley; Dovi Poznanski; Cassie A. Reuter; James Scala; Franklin J. D. Serduke; Joseph C. Shields; Brandon J. Swift; John L. Tonry; Schuyler D. Van Dyk; Xiaofeng Wang; Diane S. Wong
A Low Noise NbTiN-based 850 GHz SIS Receiver for the
the 350 micron atmospheric window. This frequency band lies entirely above the energy gap of niobium (700 that consists of two Nb/AlN/NbTiN tunnel junctions, NbTiN thin-film microstrip tuning elements, and a Nb window was deployed at the CSO. It used a novel 1 ┬Ąm thick Silicon Nitride membrane which support an all
The effect of turbulent intermittency on the deflagration to detonation transition in SN Ia explosions
We examine the effects of turbulent intermittency on the deflagration to detonation transition (DDT) in Type Ia supernovae. The Zel'dovich mechanism for DDT requires the formation of a nearly isothermal region of mixed ash and fuel that is larger than a critical size. We primarily consider the hypothesis by Khokhlov et al. and Niemeyer and Woosley that the nearly isothermal, mixed region is produced when the flame makes the transition to the distributed regime. We use two models for the distribution of the turbulent velocity fluctuations to estimate the probability as a function of the density in the exploding white dwarf that a given region of critical size is in the distributed regime due to strong local turbulent stretching of the flame structure. We also estimate lower limits on the number of such regions as a function of density. We find that the distributed regime, and hence perhaps DDT, occurs in a local region of critical size at a density at least a factor of 2-3 larger than predicted for mean conditions that neglect intermittency. This factor brings the transition density to be much larger than the empirical value from observations in most situations. We also consider the intermittency effect on the more stringent conditions for DDT by Lisewski et al. and Woosley. We find that a turbulent velocity of $10^8$ cm/s in a region of size $10^6$ cm, required by Lisewski et al., is rare. We expect that intermittency gives a weaker effect on the Woosley model with stronger criterion. The predicted transition density from this criterion remains below $10^7$ g/cm$^3$ after accounting for intermittency using our intermittency models.
Liubin Pan; J. Craig Wheeler; John Scalo
Search for double degenerate progenitors of supernovae type Ia with SPY
We report on a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (SN Ia Progenitor surveY - SPY). About 560 white dwarfs were checked for radial velocity variations until now. Ninety new DDs have been discovered, including short period systems with masses close to the Chandrasekhar mass.
R. Napiwotzki; N. Christlieb; H. Drechsel; H. -J. Hagen; U. Heber; D. Homeier; C. Karl; D. Koester; B. Leibundgut; T. R. Marsh; S. Moehler; G. Nelemans; E. -M. Pauli; D. Reimers; A. Renzini; L. Yungelson
Micro artificial muscle fiber using NiTi spring for soft robotics Sangbae Kim, Elliot Hawkes, Kyujin Cho, Matthew Jolda, Joe Foley and Robert Wood
from shape memory alloy (NiTi) coiled springs. An enhanced spring NiTi model describes the combination of micro-coil spring, we present a novel mesh-worm prototype that utilizes bio-inspired antagonistic structure alteration, NiTi can be restructured into coil springs. Chang et al.[1], discuss the numerous
Wood, Robert
Analytical Expressions For Light-Curves Of Ordinary And Superluminous Supernovae Type Ia
Ordinary supernovae of type Ia (SNeIa) may be produced by the thermonuclear explosion of white dwarfs (WDs), which after their nascence in proto-planetary nebulae accrete fall-back matter and approach the Chandrasekhar mass limit. If the detonation continues into the fall-back layer and/or if the SNIa debris collide with it, they may produce a super Chandrasekhar SNIa. A few underlying physical assumptions of such model yield a very simple master formula that reproduces quite well the bolometric light-curves of both ordinary and supeluminous SNeIa. Other main properties of SNeIa, including the empirical 'brighter-slower' Philipps' relation that was used to standardize ordinary SNeIa as distance indicators and led to the discovery of the accelerating expansion of the universe are also reproduced.
Shlomo Dado; Arnon Dar
Type Ia supernova rate studies from the SDSS-II Supernova Study
The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered {approx} 500 spectroscopically confirmed SNe Ia with densely sampled (once every {approx} 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents {approx} 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.
Dilday, Benjamin; /Chicago U.
Type Ia supernovae selection and forecast of cosmology constraints for the Dark Energy Survey
Science Journals Connector (OSTI)
We present the results of a study of selection criteria to identify Type Ia supernovae photometrically in a simulated mixed sample of Type Ia supernovae and core collapse supernovae. The simulated sample is a mockup of the expected results of the Dark Energy Survey. Fits to the \\{MLCS2k2\\} and SALT2 Type Ia supernova models are compared and used to help separate the Type Ia supernovae from the core collapse sample. The Dark Energy Task Force Figure of Merit (modified to include core collapse supernovae systematics) is used to discriminate among the various selection criteria. This study of varying selection cuts for Type Ia supernova candidates is the first to evaluate core collapse contamination using the Figure of Merit. Different factors that contribute to the Figure of Merit are detailed. With our analysis methods, both SALT2 and \\{MLCS2k2\\} Figures of Merit improve with tighter selection cuts and higher purities, peaking at 98% purity.
Eda Gjergo; Jefferson Duggan; John D. Cunningham; Steve Kuhlmann; Rahul Biswas; Eve Kovacs; Joseph P. Bernstein; Harold Spinka
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feed-image feed-image Digg: ALSBerkeleyLab Facebook Page: 208064938929 Flickr: advancedlightsource Twitter: ALSBerkeleyLab YouTube: AdvancedLightSource Home About the ALS ALS@20 ALS@20 ALS@20 Kick-Off Celebration Print On Friday, January 11, the Advanced Light Source celebrated the beginning of its 20th anniversary year with a brunch attended by more than 150 current and past staff members. After introductory remarks describing the trials and tribulations encountered during the construction of the ALS from former Director Jay Marx, current ALS Scientific Director Steve Kevan and Director Roger Falcone talked about the progress of the facility over the years. Attendees were then able to view more than 500 historical photos of the ALS and its staff displayed around the room.
Microsoft PowerPoint - IEEE IAS PES 102313.pptx
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DOE's ARRA DOE's ARRA Smart Grid Program Steve Bossart, Senior Energy Analyst IEEE IAS/PES Pittsburgh Section October 23, 2013 ŌĆ╣#ŌĆ║ Topics * OE ARRA Smart Grid Program * OE ARRA Smart Grid Progress * Results and Case Studies * Life After ARRA Smart Grid ŌĆ╣#ŌĆ║ DOE OE ARRA Smart Grid Program ŌĆ╣#ŌĆ║ American Recovery and Reinvestment Act ($4.5B) * Smart Grid Investment Grants (99 projects) - $3.4 billion Federal; $4.7 billion private sector - > 800 PMUs covering almost 100% of transmission - ~ 8000 distribution automation circuits - > 15 million smart meters * Smart Grid Demonstration Projects (32 projects) - $685 million Federal; $1 billion private sector - 16 storage projects - 16 regional demonstrations Smart Grid ARRA Activities ŌĆ╣#ŌĆ║ Smart Grid investment from ARRA field projects
Type Ia Supernova: Burning and Detonation in the Distributed Regime
A simple, semi-analytic representation is developed for nuclear burning in Type Ia supernovae in the special case where turbulent eddies completely disrupt the flame. The speed and width of the ``distributed'' flame front are derived. For the conditions considered, the burning front can be considered as a turbulent flame brush composed of corrugated sheets of well-mixed flames. These flames are assumed to have a quasi-steady-state structure similar to the laminar flame structure, but controlled by turbulent diffusion. Detonations cannot appear in the system as long as distributed flames are still quasi-steady-state, but this condition is violated when the distributed flame width becomes comparable to the size of largest turbulent eddies. When this happens, a transition to detonation may occur. For current best estimates of the turbulent energy, the most likely density for the transition to detonation is in the range 0.5 - 1.5 x 10^7 g cm^{-3}.
S. E. Woosley
Ann bay lodyans 7 / se Bryant Freeman ("Tonton Liben") ki pare ti liv sa a
pou I pase akote. Ti djab la bare I: "Kwa kwa kwa! Ala chans m genyen jodi a. Mwen chita chita m, epi yon vyann vin jwenn mwen. Ki kote ou prale, ti neg?" Dyedone komanse tranble. Men li C^*M pran kouraj li ak 2 men, li pran chante pou ti djab... m pito pa vann." 2 Wa a karese Malis, li pwomet li tout pwoteksyon. Alafen, li louvri men Malis, li depoze san dola ladann. Le msye we bel fey lajan, li dako pou ba Wa a ti lanp la. Epi, nan denmen, Malis al achte yon vye bourik ak kob la...
Freeman, Bryant C., ed.
A mutant of Escherichia coli defective in penicillin-binding protein 5 and lacking D-alanine carboxypeptidase IA.
Science Journals Connector (OSTI)
...preparation of D-alanrne car- boxypeptidase IA of...IA, because a mutant defective in D-alanine carbox...both activities were defective or both were normal...residual D-alanine car- boxypeptidase IA activity...and to obtain a mutant defective in PBP-6 are in progress...
Y Nishimura; H Suzuki; Y Hirota; J T Park
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Industry @ ALS Industry @ ALS Industry @ ALS Concrete Industry Benefits from Ancient Romans and the ALS Print Thursday, 17 October 2013 14:24 New insights into the Romans' ingenious concrete harbor structures emerging from ALS beamline research could move the modern concrete industry toward its goal of a reduced carbon footprint. Summary Slide Read more... Moving Industry Forward: Finding the Environmental Opportunity in Biochar Print Thursday, 12 September 2013 08:41 Using ALS Beamlines 10.3.2 and 8.3.2, the Environmental Protection Agency (EPA) is currently investigating how biochar sorbs environmental toxins and which kinds of biochar are the most effective. The possibilities for widespread use have already launched entrepreneurial commercial ventures. Summary Slide
The Allende meteorite: evidence for a new cosmothermometer based on Ti3+/Ti4+
Science Journals Connector (OSTI)
... 1,765 Perovskite CaTiO3 1,647 1,393 Melilite Ca2Al2SiO7- 1,625 1,450 Ca2MgSi2O7 Spinel MgAl2O4 1,513 1,362 Metallic iron Fe(Fe-Ni) 1,473 Diopside CaMgSi2O6 ... rhonite and fassaite compositions are for rhonites that have decomposed to fassaite + perovskite + spinel. Open circles represent intra-crystalline fassaites. The dashed line marked ALL-4 is the ...
Stephen E. Haggerty
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including Ethan Crumlin (at right) about current research in energy storage and battery efficiency. Berkeleyside Editor Lance Knoble toured the ALS and Berkeley Lab with...
Tension and Systematics in the Gold06 SnIa Dataset
The Gold06 SnIa dataset recently released in astro-ph/0611572 consists of five distinct subsets defined by the group or instrument that discovered and analyzed the corresponding data. These subsets are: the SNLS subset (47 SnIa), the HST subset (30 SnIa), the HZSST subset (41 SnIa), the SCP subset (26 SnIa) and the Low Redshift (LR) subset (38 SnIa). These subsets sum up to the 182 SnIa of the Gold06 dataset. We use Monte-Carlo simulations to study the statistical consistency of each one of the above subsets with the full Gold06 dataset. In particular, we compare the best fit $w(z)$ parameters (w_0,w_1) obtained by subtracting each one of the above subsets from the Gold06 dataset (subset truncation), with the corresponding best fit parameters (w^r_0,w^r_1) obtained by subtracting the same number of randomly selected SnIa from the same redshift range of the Gold06 dataset (random truncation). We find that the probability for (w^r_0,w^r_1)=(w_0,w_1) is large for the Gold06 minus SCP (Gold06-SCP) truncation but is less than 5% for the Gold06-SNLS, Gold06-HZSST and Gold06-HST truncations. This result implies that the Gold06 dataset is not statistically homogeneous. By comparing the values of the best fit (w_0,w_1) for each subset truncation we find that the tension among subsets is such that the SNLS and HST subsets are statistically consistent with each other and `pull' towards LCDM (w_0=-1,w_1=0) while the HZSST subset is statistically distinct and strongly `pulls' towards a varying w(z) crossing the line $w=-1$ from below (w_00). We also isolate six SnIa that are mostly responsible for this behavior of the HZSST subset.
S. Nesseris; L. Perivolaropoulos
Type Ia Supernova Spectral Line Ratios as Luminosity Indicators
crucial role in the discovery of the dark energy, v i a theled to the discovery of the "dark energy" (Riess et al.
Bongard, Sebastien; Baron, E.; Smadja, G.; Branch, David; Hauschildt, Peter H.
Solar abundance of manganese: a case for the existence of near Chandrasekhar-mass Type Ia supernova progenitors
Context: Manganese is predominantly synthesised in Type Ia supernova (SN Ia) explosions. Owing to the entropy dependence of the Mn yield in explosive thermonuclear burning, SNe Ia involving near Chandrasekhar-mass white dwarfs (WDs) are predicted to produce Mn to Fe ratios significantly exceeding those of SN Ia explosions involving sub-Chandrasekhar mass primary WDs. Of all current supernova explosion models, only SN Ia models involving near-Chandrasekhar mass WDs produce [Mn/Fe] > 0.0. Aims: Using the specific yields for competing SN Ia scenarios, we aim to constrain the relative fractions of exploding near-Chandrasekhar mass to sub-Chandrasekhar mass primary WDs in the Galaxy. Methods: We extract the Mn yields from three-dimensional thermonuclear supernova simulations referring to different initial setups and progenitor channels. We then compute the chemical evolution of Mn in the Solar neighborhood, assuming SNe Ia are made up of different relative fractions of the considered explosion models. Results: We ...
Seitenzahl, Ivo R; Roepke, Friedrich K; Ruiter, Ashley J
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ALS Visitors ALS Visitors ALS Visitors Print Wednesday, 29 July 2009 00:00 ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.
Rates, progenitors and cosmic mix of Type Ia supernovae
Science Journals Connector (OSTI)
......2004) from the supernova survey spin-off of the GOODS project (Giavalisco et al. 2004). The mentioned Gaussian DDT is...fig. 13 in Greggio (2005). For this reason, we take the liberty of re-discussing here the Della Valle et al. interpretation......
Laura Greggio; Alvio Renzini; Emanuele Daddi
INDECOMPOSABLE RACKS OF ORDER p2 MAT'IAS GRA"NA
INDECOMPOSABLE RACKS OF ORDER p2 MAT'IAS GRA"NA Abstract.We classify indecomposable racks of order p2(p a prime). There a of prime order is trivial. 1.Introduction Racks and quandles have
Gra├▒a, Mat├Łas
Structural studies of allosteric regulation in the class Ia Ribonucleotide reductase from Escherichia coli
Ribonucleotide reductase (RNR) converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication and repair. The E. coli class Ia enzyme requires two subunits to catalyze the radical-based reduction ...
Zimanyi, Christina Marie
Infrastructure Assessment Mission: USACE Infrastructure Assessment (IA) Planning and Response Teams (PRTs) have two main
, and structural engineering applications; urban search & rescue (US&R) support; and water/wastewater) include pre- and post-declaration support for deploying an IA management cell, water/wastewater assessment
US Army Corps of Engineers
Gamma-rays from Type Ia supernova SN2014J
The whole set of INTEGRAL observations of type Ia supernova SN2014J, covering the period 16-162 days after the explosion has being analyzed. For spectral fitting the data are split into early and late periods covering days 16-35 and 50-162, respectively, optimized for Ni-56 and Co-56 lines. As expected for the early period much of the gamma-ray signal is confined to energies below $\\sim$200 keV, while for the late period it is most strong above 400 keV. In particular, in the late period Co-56 lines at 847 and 1248 keV are detected at 4.7 and 4.3 sigma respectively. The lightcurves in several representative energy bands are calculated for the entire period. The resulting spectra and lightcurves are compared with a subset of models. We confirm our previous finding that the gamma-ray data are broadly consistent with the expectations for canonical 1D models, such as delayed detonation or deflagration models for a near-Chandrasekhar mass WD. Late optical spectra (day 136 after the explosion) show rather symmetric ...
Churazov, E; Isern, J; Bikmaev, I; Bravo, E; Chugai, N; Grebenev, S; Jean, P; Kn÷dlseder, J; Lebrun, F; Kuulkers, E
2010-2011 Depto. Ciencia de la Computacin e IA Especialista Universitario Java Enterprise
┬® 2010-2011 Depto. Ciencia de la Computaci├│n e IA Especialista Universitario Java Enterprise Struts Sesi├│n 4: Introducci├│n a Struts 2 #12;┬® 2010-2011 Depto. Ciencia de la Computaci├│n e IA Especialista ┬Ę Taglibs ┬Ę Internacionalizaci├│n ┬Ę Validaci├│n ┬Ę Conceptos nuevos en Struts 2 #12;┬® 2010-2011 Depto. Ciencia
Escolano, Francisco
Experto Universitario Java Enterprise 2012-2013 Depto. Ciencia de la Computacin e IA
Experto Universitario Java Enterprise ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Lenguaje Java Avanzado Sesi├│n 3: Tratamiento de errores #12;Lenguaje Java Avanzado ┬® 2012-2013 Depto. Ciencia de ┬Ę Tipos gen├®ricos #12;Lenguaje Java Avanzado ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Errores - 3
Escolano, Francisco
Constraining the double-degenerate scenario for Type Ia supernovae from merger ejected matter
We follow the mass blown during the WD-WD merger process in the Double-Degenerate (DD) scenario for type Ia supernovae (SN Ia), and find that the interaction of the SN ejecta with this wind affects the early (thermal energy and then to additional radiation. The radiation could be interpreted as an explosion originating from a progenitor having a radius of one solar radius or more, contradicting observations of SN 2011fe.
Levanon, Naveh; GarcĒa-Berro, Enrique
NLE Websites -- All DOE Office Websites (Extended Search)
ALS Visitors Print ALS Visitors Print ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.
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Al Weinrub Al Weinrub Author, "COMMUNITY POWER: Decentralized Renewable Energy in California" Member, Sierra Club California Clean Energy-Climate CommitteeMember, Steering Committee, Bay Area Clean Energy Alliance email@example.com This speaker was a visiting speaker who delivered a talk or talks on the date(s) shown at the links below. This speaker is not otherwise associated with Lawrence Berkeley National Laboratory, unless specifically identified as a Berkeley Lab staff member. Al Weinrub is a member of the Sierra Club California Energy-Climate Committee and serves on the Steering Committee of the Bay Area's Local Clean Energy Alliance. He is the author of COMMUNITY POWER: Decentralized Renewable Energy in California (http://www.localcleanenergy.org/Community-Power-Publication)
THE DISCOVERY OF THE MOST DISTANT KNOWN TYPE Ia SUPERNOVA AT REDSHIFT 1.914
We present the discovery of a Type Ia supernova (SN) at redshift z = 1.914 from the CANDELS multi-cycle treasury program on the Hubble Space Telescope (HST). This SN was discovered in the infrared using the Wide-Field Camera 3, and it is the highest-redshift Type Ia SN yet observed. We classify this object as a SN Ia by comparing its light curve and spectrum with those of a large sample of Type Ia and core-collapse SNe. Its apparent magnitude is consistent with that expected from the {Lambda}CDM concordance cosmology. We discuss the use of spectral evidence for classification of z > 1.5 SNe Ia using HST grism simulations, finding that spectral data alone can frequently rule out SNe II, but distinguishing between SNe Ia and SNe Ib/c can require prohibitively long exposures. In such cases, a quantitative analysis of the light curve may be necessary for classification. Our photometric and spectroscopic classification methods can aid the determination of SN rates and cosmological parameters from the full high-redshift CANDELS SN sample.
Jones, David O.; Rodney, Steven A.; Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Dahlen, Tomas; Casertano, Stefano; Koekemoer, Anton [Space Telescope Science Institute, Baltimore, MD 21218 (United States); McCully, Curtis; Keeton, Charles R.; Patel, Brandon [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States); Frederiksen, Teddy F.; Hjorth, Jens [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Strolger, Louis-Gregory [Department of Physics, Western Kentucky University, Bowling Green, KY 42101 (United States); Wiklind, Tommy G. [Joint ALMA Observatory, ESO, Santiago (Chile); Challis, Peter [Harvard/Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Graur, Or [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Hayden, Brian; Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Weiner, Benjamin J. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); and others
Active Oxygen on Au/TiO2 Catalysts DOI: 10.1002/anie.201102062 Active oxygen on a Au/TiO2 catalyst Formation, stability and CO
1 Active Oxygen on Au/TiO2 Catalysts DOI: 10.1002/anie.201102062 Active oxygen on a Au/TiO2 are the activation of molecular oxygen, the active site for this reaction step, and the nature of the catalytically active oxygen species present under working conditions.[3;9-15] Stiehl et al. had shown that molecularly
Pfeifer, Holger
CIMAT, VIII Escuela de verano, 30 de julio -12 de agos* Introducci'on a la Geometr'ia de la Mec'anic*
* *fluencia de una fuerza F(x) se define su energ'ia (como funci'on de su posici'on y velocidad) por E = T +* * V donde la energ'ia cin'etica T = m(x`)2=2 y la energ'ia potencial V (x) es una funci'on que(x) entonces su energ* *'ia E se mantiene constante en el tiempo (la Ley de Conservaci'on de Energ'ia
Bor, Gil
THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE
We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.
Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q. [Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States); Fisher, R. T. [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Townsley, D. M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Meakin, C. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Reid, L. B. [NTEC Environmental Technology, Subiaco WA 6008 (Australia)
Off-center ignition in type Ia supernova: I. Initial evolution and implications for delayed detonation
The explosion of a carbon-oxygen white dwarf as a Type Ia supernova is known to be sensitive to the manner in which the burning is ignited. Studies of the pre-supernova evolution suggest asymmetric, off-center ignition, and here we explore its consequences in two- and three-dimensional simulations. Compared with centrally ignited models, one-sided ignitions initially burn less and release less energy. For the distributions of ignition points studied, ignition within two hemispheres typically leads to the unbinding of the white dwarf, while ignition within a small fraction of one hemisphere does not. We also examine the spreading of the blast over the surface of the white dwarf that occurs as the first plumes of burning erupt from the star. In particular, our studies test whether the collision of strong compressional waves can trigger a detonation on the far side of the star as has been suggested by Plewa et al. (2004). The maximum temperature reached in these collisions is sensitive to how much burning and expansion has already gone on, and to the dimensionality of the calculation. Though detonations are sometimes observed in 2D models, none ever happens in the corresponding 3D calculations. Collisions between the expansion fronts of multiple bubbles also seem, in the usual case, unable to ignite a detonation. "Gravitationally confined detonation" is therefore not a robust mechanism for the explosion. Detonation may still be possible in these models however, either following a pulsation or by spontaneous detonation if the turbulent energy is high enough.
F. K. Roepke; S. E. Woosley; W. Hillebrandt
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Quick Facts Quick Facts ALS Visitors Print ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.
Verifying the Cosmological Utility of Type Ia Supernovae: Implications of a Dispersion in the Ultraviolet Spectra
We analyze the mean rest-frame ultraviolet (UV) spectrum of Type Ia Supernovae (SNe) and its dispersion using high signal-to-noise ratio Keck-I/LRIS-B spectroscopy for a sample of 36 events at intermediate redshift (z=0.5) discovered by the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We introduce a new method for removing host galaxy contamination in our spectra, exploiting the comprehensive photometric coverage of the SNLS SNe and their host galaxies, thereby providing the first quantitative view of the UV spectral properties of a large sample of distant SNe Ia. Although the mean SN Ia spectrum has not evolved significantly over the past 40percent of cosmic history, precise evolutionary constraints are limited by the absence of a comparable sample of high-quality local spectra. The mean UV spectrum of our z~;;=0.5 SNe Ia and its dispersion is tabulated for use in future applications. Within the high-redshift sample, we discover significant UV spectral variations and exclude dust extinction as the primary cause by examining trends with the optical SN color. Although progenitor metallicity may drive some of these trends, the variations we see are much larger than predicted in recent models and do not follow expected patterns. An interesting new result is a variation seen in the wavelength of selected UV features with phase. We also demonstrate systematic differences in the SN Ia spectral features with SN light curve width in both the UV and the optical. We show that these intrinsic variations could represent a statistical limitation in the future use of high-redshift SNe Ia for precision cosmology. We conclude that further detailed studies are needed, both locally and at moderate redshift where the rest-frame UV can be studied precisely, in order that future missions can confidently be planned to fully exploit SNe Ia as cosmological probes.
Nugent, Peter E; Ellis, R.S.; Sullivan, M.; Nugent, P.E.; Howell, D.A.; Gal-Yam, A.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; Carlberg, R.; Conley, A.; Fouchez, D.; Guy, J.; Hardin, D.; Hook, I.; Pain, R.; Perrett, K.; Pritchet, C.J.; Regnault, N.
Utilizing Type Ia Supernovae in a Large, Fast, Imaging Survey to Constrain Dark Energy
We study the utility of a large sample of type Ia supernovae that might be observed in an imaging survey that rapidly scans a large fraction of the sky for constraining dark energy. We consider information from the traditional luminosity distance test as well as the spread in SNeIa fluxes at fixed redshift induced by gravitational lensing. We include a treatment of photometric redshift uncertainties in our analysis. Our primary result is that the information contained in the mean distance moduli of SNeIa and the dispersion among SNeIa distance moduli complement each other, breaking a degeneracy between the present dark energy equation of state and its time variation without the need for a high-redshift supernova sample. To address photometric redshift uncertainties, we present dark energy constraints as a function of the size of an external set of spectroscopically-observed SNeIa that may be used for redshift calibration, nspec. We find that an imaging survey can constrain the dark energy equation of state at the epoch where it is best constrained with a 1-sigma error of sigma(wpiv)~0.03-0.09$, depending upon various assumptions. In addition, the marginal improvement in the error sigma(wpiv) from an increase in the spectroscopic calibration sample drops once nspec ~ 10^3. This result is important because it is of the order of the size of calibration samples likely to be compiled in the coming decade and because, for samples of this size, the spectroscopic and imaging surveys individually place comparable constraints on the dark energy equation of state. In all cases, it is best to calibrate photometric redshifts with a set of spectroscopically-observed SNeIa with relatively more objects at high redshift than the parent sample of imaging SNeIa.
Andrew R. Zentner; Suman Bhattacharya
Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae -- Final Technical Report
Type Ia supernovae (SNe Ia; exploding white-dwarf stars) were the key to the Nobel-worthy 1998 discovery and subsequent verification that the expansion of the Universe is accelerating, driven by the effects of dark energy. Understanding the nature of this mysterious, yet dominant, component of the Universe is at the forefront of research in cosmology and fundamental physics. SNe Ia will continue to play a leading role in this enterprise, providing precise cosmological distances that improve constraints on the nature of dark energy. However, for this effort to succeed, we need to more thoroughly understand relatively nearby SNe Ia, because our conclusions come only from comparisons between them and distant (high-redshift) SNe Ia. Thus, detailed studies of relatively nearby SNe Ia are the focus of this research program. Many interesting results were obtained during the course of this project; these were published in 32 refereed research papers that acknowledged the grant. A major accomplishment was the publication of supernova (SN) rates derived from about a decade of operation of the Lick Observatory Supernova Search (LOSS) with the 0.76-meter Katzman Automatic Imaging Telescope (KAIT). We have determined the most accurate rates for SNe of different types in large, nearby galaxies in the present-day Universe, and these can be compared with SN rates far away (and hence long ago in the past) to set constraints on the types of stars that explode. Another major accomplishment was the publication of the light curves (brightness vs. time) of 165 SNe Ia, along with optical spectroscopy of many of these SNe as well as other SNe Ia, providing an extensive, homogeneous database for detailed studies. We have conducted intensive investigations of a number of individual SNe Ia, including quite unusual examples that allow us to probe the entire range of SN explosions and provide unique insights into these objects and the stars before they explode. My team's studies have also led to the identification of subsamples of SNe Ia that can be used to provide the most reliable cosmological distances, and we developed ways to deal with the dust that makes SNe Ia appear fainter than they really are. Using the KAIT/LOSS sample, we produced an excellent Hubble diagram (galaxy recession speed vs. distance), accurately showing the expansion of the Universe. Even smaller scatter was achieved when spectroscopic characteristics were taken into account. Another high-quality Hubble diagram was constructed with SNe Ia from the Sloan Digital Sky Survey (SDSS). These Hubble diagrams provide useful new constraints on the nature of the dark energy that is accelerating the expansion of the Universe. As an added bonus of our research, we also studied core-collapse SNe, which differ fundamentally from SNe Ia.
Filippenko, Alexei Vladimir [Univ. California, Berkeley
E-Print Network 3.0 - al hf ta Sample Search Results
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a JEOL electron microprobe and Ca, Ti, Nb, Ta, Hf and Zr abundances measured using laser ablation... for an Al-rich chon- drule. As Figure 1 shows there is little evidence for...
Effects of Point Defects and Impurities on Kinetics in NaAlH4
Energy.gov (U.S. Department of Energy (DOE))
A presentation showing that point defects play an important role in the kinetics of NaAlH4 including vacancies and interstitials consistent with observed effects of Ti.
E-Print Network 3.0 - al metal irradiated Sample Search Results
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Accelerator Beams , H. Ludewig1 Summary: effects on CTE of super-Invar. Figure 3: "Gum Metal" material characterization in its non-irradiated state... driver. Ti-6Al-4V....
E-Print Network 3.0 - al bulk crystals Sample Search Results
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are homogeneously dispersed in the residual glass of the bulk for Tc... consists of titanite (CaTiSiO5) and anorthite (CaAl2Si2O8) crystals that have nucleated heterogeneously......
Formation of Ti-B surface alloys by excimer laser mixing
We have formed a surface Ti-B alloy by excimer laser mixing of a single B layer on a Ti-6Al-4V alloy substrate. Rutherford backscattering spectroscopy indicates a uniform B:Ti ratio of approximately 0.7 in the surface layer. A Boron layer 60 nm thick resulted in an alloy layer approximately 200 nm thick. There is little indication, by either Auger electron spectroscopy or nuclear reaction analysis, of substantial oxygen incorporation in the surface alloy despite the fact that the processing was done in air. Transmission electron microscopy of the surface alloy shows a completely amorphous surface layer underlain by a martensitic structure.
Jervis, T.R.; Nastasi, M.; Hirvonen, J.P.; Zocco, T.G.
Office of Legacy Management (LM)
AL. I AL. I Department of Energy Washington, DC 20545 OCT 13 Vii87 Mr. John T. Shields A214 National Fertilizer Development Center Tennessee Valley Authority Muscle Shoals, Alabama 35660 Dear Mr. Shields: As you may know, the Department of Energy (DOE) is evaluating the radiological condition of sites that were utilized under the Manhattan Engineer District and the Atomic Energy Commission (AEC) during the early years of nuclear development to determine whether they need remedial action and whether the Department has authority to perform such action. AEC work at the TVA during the period 1951 through 1955 involved the development of a process to recover uranium from the production of phosphate fertilizer. A laboratory and pilot plant were operated at the site, but very little
IAS15: a fast, adaptive, high-order integrator for gravitational dynamics, accurate to machine precision over a billion orbits
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......error behaves like a random walk. Our tests show that ias15 is superior to a mixed-variable...that ias15 follows Brouwer's law. We test our integrator in a wide variety of cases...focus on the two-body problem, a simple test case where we know the correct answer......
Hanno Rein; David S. Spiegel
Thermodynamics of TiO{sub x} in blast furnace-type slags
Equilibrium studies between CaO-SiO{sub 2}-10 pct MgO-Al{sub 2}O{sub 3}-TiO{sub 1.5}-TiO{sub 2} slags, carbon-saturated iron, and a carbon monoxide atmosphere were performed at 1773 K to determine the activities of TiO{sub 1.5} and TiO{sub 2} in the slag. These thermodynamic parameters are required to predict the formation of titanium carbonitride in the blast furnace. In order to calculate the activity of titanium oxide, the activity coefficient of titanium in carbon-saturated iron-carbon-titanium alloys was determined by measuring the solubility of titanium in carbon-saturated iron in equilibrium with titanium carbide. The solubility and the activity coefficient of titanium obtained were 1.3 pct and 0.023 relative to 1 wt pct titanium in liquid iron or 0.0013 relative to pure solid titanium at 1773 K, respectively. Over the concentration range studied, the effect of the TiO{sub x} content on its activity coefficient is small. In the slag system studied containing 35 to 50 pct CaO, 25 to 45 pct SiO{sub 2}, 7 to 22 pct Al{sub 2}O{sub 3}, and 10 pct MgO, the activity coefficients of TiO{sub 1.5} and TiO{sub 2} relative to pure solid standard states range from 2.3 to 8.8 and from 0.1 to 0.3, respectively. Using thermodynamic data obtained, the prediction of the formation of titanium carbonitride was made. Assuming hypothetical TiO{sub 2}, i.e., total titanium in the slag expressed as TiO{sub 2}, and using the values of the activity coefficients of TiO{sub 1.5} and TiO{sub 2} determined, the equilibrium distribution of titanium between blast furnace-type slags and carbon-saturated iron was computed. The value of [pct Ti]/(pct TiO{sub 2}) ranges from 0.1 to 0.2.
Morizane, Y.; Ozturk, B.; Fruehan, R.J. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering
Fabrication of functionally graded TiC/Ti composites by Laser Engineered Net Shaping
engineered net shaping (LENS), with compositions changing from pure Ti to approximately 95 vol% TiC; Microstructure; TiC carbide 1. Introduction Functionally graded materials (FGMs) are a class of advanced
DuPont, John N.
FROM RACKS TO POINTED HOPF ALGEBRAS NICOL #19; AS ANDRUSKIEWITSCH AND MAT #19; IAS GRA ~ NA (C X; c q ), where X is a rack and q is a 2-cocycle on X with values in C #2; . Racks and cohomology of racks appeared also in the work of topologists. This leads us to the study of the structure of racks
Gra├▒a, Mat├Łas
Section I. Summary of Project Activities Section I-A. 2008-2009 Project Summary
Section I. Summary of Project Activities Section I-A. 2008-2009 Project Summary University year, we accomplished the following: ┬Ę Established a dual career opportunity procedure vetted to address, communicate procedures for the new daycare facility, and to explore the potential
Farritor, Shane
SEASONAL V A R IA TIONS IN STRUCTURE AND CIRCULATION IN THE RED SEA A DISSERTATION SUBMITTE D and surface circulation in the Red Sea, occur r ing along the north-south axis of the Sea and extending fr om on in the northern Red Sea is frorn the nor th-northwest throughout the year' during the winter ( fr om October
Luther, Douglas S.
Seminar Ia, cetrti letnik, stari program LONGITUDINAL DYNAMICS OF PARTICLES IN ACCELERATORS
Seminar Ia, cetrti letnik, stari program LONGITUDINAL DYNAMICS OF PARTICLES IN ACCELERATORS Author motion of charged particles in particle accelerators. The technique of acceleration by electromagnetic waves is explored and the stability of motion under such acceleration is inspected. The seminar
┬?umer, Slobodan
Final Technical Report: Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae
The final technical report from the project "Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae" led at Rutgers the State University of New Jersey by Prof. Saurabh W. Jha is presented, including all publications resulting from this award.
Saurabh W. Jha
SponSored by http://www.ntu.edu.sg/ias/oCpA8
SponSored by http://www.ntu.edu.sg/ias/oCpA8 International Conference on physics education ┬Ę Statistical and Nonlinear physics ┬Ę Science Education ┬Ę Women in Physics Sir Michael PEPPER Univ. College or poster presentations. All posters at the conference will be considered for the 2014 OCPA-APS Outstanding
Faraon, Andrei
THE CARNEGIE SUPERNOVA PROJECT: SECOND PHOTOMETRY DATA RELEASE OF LOW-REDSHIFT TYPE Ia SUPERNOVAE
The Carnegie Supernova Project (CSP) was a five-year observational survey conducted at Las Campanas Observatory that obtained, among other things, high-quality light curves of {approx}100 low-redshift Type Ia supernovae (SNe Ia). Presented here is the second data release of nearby SN Ia photometry consisting of 50 objects, with a subset of 45 having near-infrared follow-up observations. Thirty-three objects have optical pre-maximum coverage with a subset of 15 beginning at least five days before maximum light. In the near-infrared, 27 objects have coverage beginning before the epoch of B-band maximum, with a subset of 13 beginning at least five days before maximum. In addition, we present results of a photometric calibration program to measure the CSP optical (uBgVri) bandpasses with an accuracy of {approx}1%. Finally, we report the discovery of a second SN Ia, SN 2006ot, similar in its characteristics to the peculiar SN 2006bt.
Stritzinger, Maximilian D. [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, 10691 Stockholm (Sweden); Phillips, M. M.; Campillay, Abdo; Morrell, Nidia; Krzeminski, Wojtek; Roth, Miguel [Carnegie Observatories, Las Campanas Observatory, La Serena (Chile); Boldt, Luis N. [Argelander Institut fuer Astronomie, Universitaet Bonn, D-53111 Bonn (Germany); Burns, Chris; Freedman, Wendy L.; Madore, Barry F.; Persson, Sven E. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Contreras, Carlos [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Victoria 3122 (Australia); Gonzalez, Sergio [Atacama Large Millimeter/Submillimeter Array, European Southern Observatory (Chile); Folatelli, Gaston [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Salgado, Francisco [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); DePoy, D. L.; Marshall, J. L.; Rheault, Jean-Philippe; Suntzeff, Nicholas B. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Hamuy, Mario, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com [Departamento de Astronomia, Universidad de Chile, Santiago (Chile)
Abstract IA08: PTEN and PI3K signaling in brain development and disease
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...Abstract IA08: PTEN and PI3K signaling in brain development and disease Suzanne J. Baker...an increased genetic susceptibility to brain tumors. However, inherited mutation of...and tumor suppression in the mammalian brain. Recently, germline or somatic mutations...
Suzanne J. Baker
Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1
Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1 , J. B. Bell1 , and S. E. Woosley2 oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the oxygen
The superconducting spin valve and triplet superconductivity I.A. Garifullin a,n
The superconducting spin valve and triplet superconductivity I.A. Garifullin a,n , P.V. Leksin s t r a c t A review of our recent results on the spin valve effect is presented. We have used coefficient DF and the exchange splitting I of the conduction band in the F layer [1]. For pure Fe the value
Fominov, Yakov
CIMAT, VIII Escuela de verano, 30 de julio -12 de ago* Introducci'on a la Geometr'ia de la Mec'ani*
con un valor fijo de la energ* *'ia corresponden a secciones del cono del inciso (a) por * *energ'ia tienen el mismo semi-eje mayor. 11.Demuestra la tercera ley de Kepler: toda soluci'on peri Introducci'on a la Geometr'ia de la Mec'ani* *ca Cl'asica Problemas 7 - 12
Bor, Gil
XX 3d X 3d X X XX X XX SrTiO3Ti 2p 3d SrTiO3Ti 2p 3d 2p 2p SrTiO3 ts) 2p3/2 (t2g) 2p3/2 (e ) 2p1/2 (eg)2p SrTiO3 3d unit (t2g) (eg) (eg)2p1/2 (t2g)3d (Ti Fe Cu) arb. ( 2g) (Ti, Fe, Cu) y(ansitynten 3d In 3d 468464460456 ┬Ę Photon Energy (e
Katsumoto, Shingo
AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium titanate
AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium-effect transistors have been formed by incorporating barium strontium titanate (BST) deposited by rf magnetron in increased leakage. Due to its large dielectric constant, barium strontium ti- tanate [Ba1-xSrxTiO3, (BST
York, Robert A.
Rechnungslegung Nach EG-Richtlinien, US-GAAP und IAS als M÷gliche Grundlagen Einer International Harmonisierten Rechnungslegung
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Grundsõtzlich wird mit der Harmonisierung der Rechnungslegungsvorschriften in der Europõischen Union nicht die Vereinheitlichung der Vorschriften, sondern nur die Vergleichbarkeit und Gleichwertigkeit der im J...
Kurt V. Auer
Rechnungslegung nach EG-Richtlinien, US-GAAP und IAS als M÷gliche Grundlagen Einer International Harmonisierten Rechnungslegung
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Grundsõtzlich wird mit der Harmonisierung der Rechnungslegungsvorschriften in der Europõischen Union nicht die Vereinheitlichung der Vorschriften, sondern nur die Vergleichbarkeit und Gleichwertigkeit der im J...
Kurt Vinzenz Auer
Synergistic Effect of Nano-TiO2 and Nanoclay on the Ultraviolet Degradation and Physical Properties of Wood Polymer Nanocomposites
Science Journals Connector (OSTI)
(7) The combination of nanoclay with other metal nanoparticles will influence the properties of the composites considerably, as reported by Laachachia et al. while studying the properties of poly(methyl methacrylate) (PMMA) nanocomposites prepared with TiO2 and nanoclay. ... (30) Mina et al. studied the XRD pattern of a polypropylene/titanium dioxide composite and reported a similar increase in the peak intensity of TiO2 in the composites. ...
Ankita Hazarika; Tarun K. Maji
Surface characterization and mechanical property of TiN/Ti-coated NiTi alloy by PIIID
significantly reduces the friction coefficient and improves wear resistance of the NiTi alloy. ┬® 2006 Elsevier B prosthesis, heart valve replacement and biosensors [6,7]. TiN surface coating has also been found
Zheng, Yufeng
Effect of laser irradiation on failure mechanism of TiCp reinforced titanium composite coating produced by laser cladding
Science Journals Connector (OSTI)
Abstract Laser cladding is an effective technique to coat a metallic substrate with a layer of a different nature. It has been widely reported that the most important combined parameters controlling the quality of the coating are the specific energy (E) and the powder density (?). In the present work, clad deposits of Ti6Al4VĀ+Ā60Āwt.% TiC were prepared on a Ti6Al4V substrate using an optimum combination of EcĀ=Ā24ĀJ/mm2 and ?cĀ=Ā3Āmg/mm2. These experiments were performed using a laser power of 400 and 600ĀW, in order to study the effect of laser power on the properties of the clad. The microstructure, phase composition and nanohardness of the coatings were investigated by optical microscopy, scanning electron microscopy and X-ray diffraction. During laser processing, TiC can be partially converted to TiCX (XĀ=Ā0.5) due mainly to the TiC dissolution into the laser-generated melting pool and subsequent precipitation during cooling. It was observed that the lower laser power limit reduces primary TiC dissolution but it also promotes secondary carbide alignment at the interface. On the other hand, the damage mechanism induced by high laser power is dominated by primary TiC particle cracking by the high stress concentration at the particle¢matrix interface followed by ductile failure of the matrix. It is also remarkable that irradiance affects the TiC/TiCx ratio despite Ec and ?c are fixed and it determines hardness distribution inside the coating.
J.J. Candel; J.A. Jimenez; P. Franconetti; V. Amig¾
E-Print Network 3.0 - aleaciones cu-zn-al estabilidad Sample...
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C2, suppl6mentau Journal de Physique 111,Volume 5, f6vrier 1995 Summary: The shape memory alloys which are industrially used are based upon NiTi, CuZnAl and CuAlNi to which...
IA REP0 SAND85-2809 Unlimited Release UC-92A
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IA REP0 SAND85-2809 Unlimited Release UC-92A IA REP0 SAND85-2809 Unlimited Release UC-92A Printed July 1986 High Energy Gas Fracture Experiments in Fluid-Filled Boreholes-Potential Geothermal Application J. F. Cuderman, T. Y. Chu, J. Jung, R. D. Jacobson Prepared by Sandia National Laboratories Albuquerque, New Mexico 87 185 and Livermore, California 94550 for the United States Department of Energy under Contract DE-AC04-76DP00789 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process
File:USDA-CE-Production-GIFmaps-IA.pdf | Open Energy Information
IA.pdf IA.pdf Jump to: navigation, search File File history File usage Iowa Ethanol Plant Locations Size of this preview: 776 ├Ś 600 pixels. Full resolution ŌĆÄ(1,650 ├Ś 1,275 pixels, file size: 303 KB, MIME type: application/pdf) Description Iowa Ethanol Plant Locations Sources United States Department of Agriculture Related Technologies Biomass, Biofuels, Ethanol Creation Date 2010-01-19 Extent State Countries United States UN Region Northern America States Iowa External links http://www.nass.usda.gov/Charts_and_Maps/Ethanol_Plants/ File history Click on a date/time to view the file as it appeared at that time. Date/Time Thumbnail Dimensions User Comment current 16:13, 27 December 2010 Thumbnail for version as of 16:13, 27 December 2010 1,650 ├Ś 1,275 (303 KB) MapBot (Talk | contribs) Automated bot upload
Mechanistic studies of proton-coupled electron transfer in aminotyrosine- and fluorotyrosine- substituted class Ia Ribonucleotide reductase
Ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to 2'- deoxynucleotides in all organisms. The class Ia RNR from Escherichia coli is active as an a2p2 complex and utilizes an unprecedented mechanism ...
Minnihan, Ellen Catherine
Generation of a stable, aminotyrosyl radical-induced ?2?2 complex of Escherichia coli class Ia ribonucleotide reductase
Ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates (dNDPs). The Escherichia coli class Ia RNR uses a mechanism of radical propagation by which a cysteine in ...
Minnihan, Ellen Catherine
Photocatalytic Degradation of VOC's by TOTO's Hydrotect (TiO2 Impregnated) Surfaces
, naturally occurs in wood and volcanic gases. Decaying organic matter can also produce methanol. Paint. This report describes the photocatalytic degradation of formaldehyde and methanol, two common VOC's, by TiO2 and methanol tests (Land et al., 2008). A standardized aqueous solution of formaldehyde and methanol was used
Bergin, Mike
IA --"-IScience Service Featuse 'I WHY T i E IJEAYIiER ?
No. 591 April 3 IA --"-IScience Service Featuse 'I WHY T i E IJEAYIiER ? II city located oa the Ice.pp';g a% Bidialo, The ice c h i l l s a t h i n laye:. of a i r aver the Sake aridto laewwd. NOW$ vhen r may be srrfficionl t o produce a sheet cloud and g i ~ eBuffalo a day not oalg dwnt arid chilly Lu
Especialista Universitario Java Enterprise 2010-2011 Depto. Ciencia de la Computacin e IA
Especialista Universitario Java Enterprise ┬® 2010-2011 Depto. Ciencia de la Computaci├│n e IA Sesi├│n 1: Introducci├│n a JMS #12;Servicios de Mensajes con JMS ┬® 2010-2011 Depto. Ciencia de la Computaci├│n ┬Ę Una Aplicaci├│n JMS ┬Ę PTP ┬Ę Pub/Sub #12;Servicios de Mensajes con JMS ┬® 2010-2011 Depto. Ciencia de la
Escolano, Francisco
On the Thermonuclear Runaway in Type Ia Supernovae: How to Run Away?
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Type Ia supernovae (SNe Ia) are thought to be thermonuclear explosions of massive white dwarfs (WDs). We present the first study of multidimensional effects during the final hours prior to the thermonuclear runaway that leads to the explosion. The calculations utilize an implicit, two-dimensional hydrodynamic code. Mixing and the ignition process are studied in detail. We find that the initial chemical structure of the WD is changed, but the material is not fully homogenized. In particular, the exploding WD sustains a central region with a low C/O ratio. This implies that the explosive nuclear burning will begin in a partially carbon-depleted environment. The thermonuclear runaway happens in a well-defined region close to the center. It is induced by compressional heat when matter is brought inward by convective flows. We find no evidence for multiple spot or strong off-center ignition. Convective velocities in the WD are on the order of 100 km s-1, which is well above the effective burning speeds in SNe Ia previously expected right after the runaway. In our calculations, the ignition occurs near the center. Then, for ? 0.5-1 s, the speed of the burning front will neither be determined by the laminar speed nor the Rayleigh-Taylor instabilities but by convective flows produced prior to the runaway. The consequences are discussed for our understanding of the detailed physics of the flame propagation, the deflagration to detonation transition, and the nucleosynthesis in the central layers. Our results strongly suggest the preconditioning of the progenitor as a key factor for our understanding of the diversity in SNe Ia.
P. H÷flich; J. Stein
Evaluation of copper for divider subassembly in MCO Mark IA and Mark IV scrap fuel baskets
The K Basin Spent Nuclear Fuel (SNF) Project Multi-Canister Overpack (MCO) subprojection eludes the design and fabrication of a canister that will be used to confine, contain, and maintain fuel in a critically safe array to enable its removal from the K Basins, vacuum drying, transport, staging, hot conditioning, and interim storage (Goldinann 1997). Each MCO consists of a shell, shield plug, fuel baskets (Mark IA or Mark IV), and other incidental equipment. The Mark IA intact and scrap fuel baskets are a safety class item for criticality control and components necessary for criticality control will be constructed from 304L stainless steel. It is proposed that a copper divider subassembly be used in both Mark IA and Mark IV scrap baskets to increase the safety basis margin during cold vacuum drying. The use of copper would increase the heat conducted away from hot areas in the baskets out to the wall of the MCO by both radiative and conductive heat transfer means. Thus copper subassembly will likely be a safety significant component of the scrap fuel baskets. This report examines the structural, cost and corrosion consequences associated with using a copper subassembly in the stainless steel MCO scrap fuel baskets.
Graves, C.E.
Observational constraints from SNe Ia and Gamma-Ray Bursts on a clumpy universe
The luminosity distance describing the effect of local inhomogeneities in the propagation of light proposed by Zeldovich-Kantowski-Dyer-Roeder (ZKDR) is tested with two probes for two distinct ranges of redshifts: supernovae Ia (SNe Ia) in 0.015 gamma-ray bursts (GRBs) in 1.547 < z < 3.57. Our analysis is performed by a Markov Chain Monte Carlo (MCMC) code that allows us to constrain the matter density parameter \\Omega_m as well as the smoothness parameter $\\alpha$ that measures the inhomogeneous-homogeneous rate of the cosmic fluid in a flat \\LambdaCDM model. The obtained best fits are (\\Omega_m=0.285^{+0.019}_{-0.018}, \\alpha= 0.856^{+0.106}_{-0.176}) from SNe Ia and (\\Omega_m=0.259^{+0.028}_{-0.028}, \\alpha=0.587^{+0.201}_{-0.202}) from GRBs, while from the joint analysis the best fits are (\\Omega_m=0.284^{+0.021}_{-0.020}, \\alpha= 0.685^{+0.164}_{-0.171}) with a \\chi^2_{\\rm red}=0.975. The value of the smoothness parameter $\\alpha$ indicates a clumped universe however it does not have an impact on the amount of dark energy (cosmological constant) needed to fit observations. This result may be an indication that the Dyer-Roeder approximation does not describe in a precise form the effects of clumpiness in the expansion of the universe.
Nora Bret¾n; Ariadna Montiel
Characterization of TiN, TiC and TiCN coatings on Ti50.6 at.% Ni alloy deposited by PIII and deposition technique
high content of nickel [1]. In addition, its wear resistance is expected to be improved by transition-metal as nitride, carbide and carbonitride, respectively. Based on the electrochemical measurement and ion carbides and nitrides coatings at a rather broad composition range, such as TiN, TiC and TiC1-xNx (0b├?b1
Zheng, Yufeng
Especialista Universitario Java Enterprise Componentes de presentacin 2012-2013 Depto. Ciencia de la Computacin e IA Sesin 4
Especialista Universitario Java Enterprise Componentes de presentaci├│n ┬® 2012-2013 Depto. Ciencia presentaci├│n ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Sesi├│n 4 Experto Universitario Java Enterprise Componentes de presentaci├│n ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Sesi├│n 4 Experto Universitario
Escolano, Francisco
Experto Universitario Java Enterprise Componentes de presentacin 2012-2013 Depto. Ciencia de la Computacin e IA Sesin 1
Experto Universitario Java Enterprise Componentes de presentaci├│n ┬® 2012-2013 Depto. Ciencia de la Universitario Java Enterprise Componentes de presentaci├│n ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Componentes de presentaci├│n ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA Sesi├│n 1 Experto Universitario
Escolano, Francisco
Utilizing Type Ia Supernovae in a Large, Fast, Imaging Survey to Constrain Dark Energy
Science Journals Connector (OSTI)
We study the utility of a large sample of Type Ia supernovae (SNe Ia) that might be observed in an imaging survey that rapidly scans a large fraction of the sky for constraining dark energy. We consider both the information contained in the traditional luminosity distance test as well as the spread in Ia SN fluxes at fixed redshift induced by gravitational lensing. As would be required from an imaging survey, we include a treatment of photometric redshift uncertainties in our analysis. Our primary result is that the information contained in the mean distance moduli of SNe Ia and the dispersion of SN Ia distance moduli complement each other, breaking a degeneracy between the present dark energy equation of state and its time variation without the need for a high-redshift (z 0.8) SN sample. Including lensing information also allows for some internal calibration of photometric redshifts. To address photometric redshift uncertainties, we present dark energy constraints as a function of the size of an external set of spectroscopically observed SNe that may be used for redshift calibration, N spec. Depending upon the details of potentially available, external SN data sets, we find that an imaging survey can constrain the dark energy equation of state at the epoch where it is best constrained w p, with a 1? error of ?(w p) ? 0.03-0.09. In addition, the marginal improvement in the error ?(w p) from an increase in the spectroscopic calibration sample drops once N spec ~ a few ? 103. This result is important because it is of the order of the size of calibration samples likely to be compiled in the coming decade and because, for samples of this size, the spectroscopic and imaging surveys individually place comparable constraints on the dark energy equation of state. In all cases, it is best to calibrate photometric redshifts with a set of spectroscopically observed SNe with relatively more objects at high redshift (z 0.5) than the parent sample of imaging SNe.
Andrew R. Zentner; Suman Bhattacharya
Au/MxOy/TiO2 catalysts for CO oxidation: promotional effect of main-group, transition, and rare-earth metal oxide additives.
Au/TiO2 catalysts are active for CO oxidation, but they suffer from high-temperature sintering of the gold particles, and few attempts have been made to promote or stabilize Au/TiO2. Our recent communication addressed these issues by loading gold onto Al2O3/TiO2 prepared via surface-sol-gel processing of Al(sec-OC4H9)3 on TiO2. In our current full paper, Au/Al2O3/TiO2 catalysts were prepared alternatively by thermal decomposition of Al(NO3)3 on TiO2 followed by loading gold, and the influences of the decomposition temperature and Al2O3 content were systematically surveyed. This facile method was subsequently extended to the preparation of a battery of metal oxide-modified Au/TiO2 catalysts virtually not reported. It was found that Au/TiO2 modified by CaO, NiO, ZnO, Ga2O3, Y2O3, ZrO2, La2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Ho2O3, Er2O3, or Yb2O3 could retain significant activity at ambient temperature even after aging in O2-He at 500 C, whereas unmodified Au/TiO2 lost its activity. Moreover, some 200 C-calcined promoted catalysts showed high activity even at about -100 C. The deactivation and regeneration of some of these new catalysts were studied. This work furnished novel catalysts for further fundamental and applied research.
Ma, Zhen [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL
NLE Websites -- All DOE Office Websites (Extended Search)
ALS Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These spaces are dedicated for...
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Safety Safety for Users ALS Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These...
Stoichiometry-driven metal-to-insulator transition in NdTiO{sub 3}/SrTiO{sub 3} heterostructures
By controlling stoichiometry via a hybrid molecular beam epitaxy approach, we report on the study of thin film growth and the electronic transport properties of phase-pure, epitaxial NdTiO{sub 3}/SrTiO{sub 3} heterostructures grown on (001) (La{sub 0.3}Sr{sub 0.7})(Al{sub 0.65}Ta{sub 0.35})O{sub 3} (LSAT) substrates as a function of cation stoichiometry in NdTiO{sub 3}. Despite the symmetry mismatch between bulk NdTiO{sub 3} and the substrate, NdTiO{sub 3} films grew in an atomic layer-by-layer fashion over a range of cation stoichiometry; however amorphous films resulted in cases of extreme cation non-stoichiometry. Temperature-dependent sheet resistance measurements were consistent with Fermi-liquid metallic behavior over a wide temperature range, but revealed a remarkable crossover from metal-to-insulator (M-I) type behavior at low temperatures for all compositions. A direct correlation between cation stoichiometry, transport behavior, and the temperature of M-I transition is established.
Xu, Peng; Phelan, Daniel; Seok Jeong, Jong; Andre Mkhoyan, K.; Jalan, Bharat, E-mail: email@example.com [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
Superior Corrosion Resistance Properties of TiN-Based Coatings on Zircaloy Tubes in Supercritical Water
Thin films of TiN and Ti0.35Al0.65N nanocomposite were deposited on polished Zircaloy-4 tubes. After exposure to supercritical water for 48 h, the coated tubes are remarkably intact, while the bare uncoated tube shows severe oxidation and breakaway corrosion. X-ray diffraction patterns, secondary electron images, backscattered electron images, and energy dispersive X-ray spectroscopy data from the tube surfaces and cross-sections show that a protective oxide, formed on the film surface, effectively prevents further oxidation and corrosion to the Zircaloy-4 tubes. This result demonstrates the effectiveness of thin film ceramics as protective coatings under extreme environments.
Fauzia Khatkhatay; Liang Jiao; Jie Jian; Zhijie Jiao; Hongbin Zhang; Jian Gan; Haiyan Wang; Wenrui Zhang; Xinghang Zhang
Oxygen Reduction Catalyzed by Au¢TiO2 Nanocomposites in Alkaline Media
Science Journals Connector (OSTI)
Au?TiO2 nanocomposite; oxygen reduction; alkaline media; RRDE; Tafel plot ... In another study, Kim et al.(14) prepared titanium oxide by heat treatment of titanium sheets in the temperature range of 600¢1000 ░C, and the best catalysts were identified as those prepared at 900 ░C where ORR occurred at the potential of about +0.65 V versus RHE in 0.1 M H2SO4. ... In a typical measurement, 1 mg of the Au¢TiO2 nanocomposite catalysts, 4 mg of carbon powder, and 10 ?L of Nafion were ultrasonically mixed in 1 mL of methanol. ...
Chan Lin; Yang Song; Lixin Cao; Shaowei Chen
Ann bay lodyans 12 / Se Bryant Freeman ("Tonton Liben") ki pare ti liv sa a
a, Bondye fe yon bon ti melanj: li pran bwode ki gen nan pan, di ki gen nan woch, fines ki gen nan ke zwazo, douse ki gen nan siwo myel, mechanste ki gen nan tig, chale ki gen nan dife, fredi ki gen nan lanej. Bondye kontwole yo, sa pa ase.... Yo te viv ansanm pandan kek tan konsa. Men yon jou, msye a al devan Bondye ansanm ak fi a. Li pote I remet Bondye. Li di konsa: "Bondye, m pa kapab viv ak zanmi ou ban mwen an. Li pale san rete, li fatige m twop, menm yon ti poze m pa kab fe. Sa...
Freeman, Bryant C.
CIMAT, VI Escuela de verano, 25 de julio 7 de agosto 1999 Introducci'on a la Geometr'ia de la Mec'anica Cl'asica
parametrizada por (x(t); Ō?? x(t)): (d) Dibujar las gr'aficas de su energ'ia cin'etica T = ( Ō?? x) 2 =2 y potencial┬Ł vaci'on de energ'ia, E = T + V = constante: (e) Repetir los 4 incisos anteriores con x(1) = 2; Ō?? x(0CIMAT, VI Escuela de verano, 25 de julio ┬Ł 7 de agosto 1999 Introducci'on a la Geometr'ia de la Mec
Bor, Gil
CIMAT, VI Escuela de verano, 25 de julio -7 de agosto 1999 Introducci'on a la Geometr'ia de la Mec'anica Cl'asica
(t), `x(t)). (d)Dibujar las gr'aficas de su energ'ia cin'etica T = (x`)2=2 y potencial* * V = x2- vaci'on de energ'ia, E = T + V = constante. (e)Repetir los 4 incisos anteriores con x(1) = 2, `x CIMAT, VI Escuela de verano, 25 de julio - 7 de agosto 1999 Introducci'on a la Geometr'ia de la
Bor, Gil
Observation of TiH5 and TiH7 in Bulk-Phase TiH3 Gels for Kubas-Type Hydrogen Storage
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Observation of TiH5 and TiH7 in Bulk-Phase TiH3 Gels for Kubas-Type Hydrogen Storage ... Table T2 provides the formulas and C, H, and Ti percentages of the hydrogenated materials in addition to those of representative stoichiometric compounds, including pure TiH3 and the starting material. ... In the TiH3 structure, the hydride ligands are a lightweight structural feature as opposed to a source of stored hydrogen, and additional hydrogen can bind via the Kubas interaction to access TiH5 and TiH7 species. ...
Tuan K. A. Hoang; Leah Morris; Daniel Reed; David Book; Michel L. Trudeau; David M. Antonelli
Study of the Detonation Phase in the Gravitationally Confined Detonation Model of Type Ia Supernovae
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We study the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia) through the detonation phase and into homologous expansion. In the GCD model, a detonation is triggered by the surface flow due to single-point, off-center flame ignition in carbon-oxygen white dwarfs (WDs). The simulations are unique in terms of the degree to which nonidealized physics is used to treat the reactive flow, including weak reaction rates and a time-dependent treatment of material in nuclear statistical equilibrium (NSE). Careful attention is paid to accurately calculating the final composition of material which is burned to NSE and frozen out in the rapid expansion following the passage of a detonation wave over the high-density core of the WD; and an efficient method for nucleosynthesis postprocessing is developed which obviates the need for costly network calculations along tracer particle thermodynamic trajectories. Observational diagnostics are presented for the explosion models, including abundance stratifications and integrated yields. We find that for all of the ignition conditions studied here a self-regulating process comprised of neutronization and stellar expansion results in final 56Ni masses of ~1.1ĀM ?. But, more energetic models result in larger total NSE and stable Fe-peak yields. The total yield of intermediate mass elements is ~0.1ĀM ? and the explosion energies are all around 1.5 ? 1051 erg. The explosion models are briefly compared to the inferred properties of recent SN Ia observations. The potential for surface detonation models to produce lower-luminosity (lower 56Ni mass) SNe is discussed.
Casey A. Meakin; Ivo Seitenzahl; Dean Townsley; George C. Jordan IV; James Truran; Don Lamb
IS WX CEN A POSSIBLE TYPE Ia SUPERNOVA PROGENITOR WITH WIND-DRIVEN MASS TRANSFER?
WX Cen is one of a few compact binary supersoft X-ray sources (CBSS) in the Galaxy that is a possible Type Ia supernova (SN Ia) progenitor. The supersoft X-ray radiation is explained as hydrostatic nuclear burning on the surface of the white dwarf component that is accreting hydrogen from a stellar companion at a high rate. If the mass donor in this system has a low mass, as has been suggested in the literature, one would expect a high wind-driven mass transfer rate. In that case, the orbital period of the system should increase. To test this theoretical prediction, we have monitored the system photometrically since 2010. By using four newly determined eclipse timings together with those collected from the literature, we discovered that the orbital period is decreasing at a rate of dP/dt = -5.15 Multiplication-Sign 10{sup -7} days yr{sup -1}. The long-term decrease in the orbital period is contrary to the prediction that the system is powered by wind-driven accretion. It therefore seems plausible that the mass donor could be more massive than the white dwarf, and that the mass transfer is driven by the thermal instability of the donor star. This finding suggests that WX Cen is a key object to check the physical mechanisms of mass accretion in CBSS. The corresponding timescale of the period change is about P/P-dot {approx} 0.81 x 10{sup 6} yr, indicating that WX Cen may evolve into an SNe Ia within one million years in the Galaxy.
Qian, S.-B.; Shi, G.; Zhu, L.-Y.; Liu, L.; Zhao, E.-G.; Li, L.-J. [Yunnan Observatories, Chinese Academy of Sciences (CAS), P.O. Box 110, 650011 Kunming (China); Fernandez Lajus, E.; Di Sisto, R. P., E-mail: email@example.com [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires (Argentina)
On the Thermonuclear Runaway in Type Ia Supernovae: How to run away?
Type Ia Supernovae are thought to be thermonuclear explosions of massive white dwarfs (WD). We present the first study of multi-dimensional effects during the final hours prior to the thermonuclear runaway which leads to the explosion. The calculations utilize an implicit, 2-D hydro code.Mixing and the ignition process are studied in detail. We find that the initial chemical structure of the WD is changed but the material is not fully homogenized. The exploding WD sustains a central region with a low C/O ratio. This implies that the explosive nuclear burning will begin in a partially C-depleted environment. The thermonuclear runaway happens in a well defined region close to the center. It is induced by compressional heat when matter is brought inwards by convective flows. We find no evidence for multiple spot or strong off-center ignition. Convective velocities are of the order of 100 km/sec which is well above the effective burning speeds in SNe Ia previously expected right after the runaway. For about 0.5 to 1 sec, the speed of the burning front will neither be determined by the laminar speed nor the Rayleigh-Taylor instabilities but by convective flows produced prior to the runaway. The consequences are discussed for our under- standing of the detailed physics of the flame propagation, the deflagration detonation transition, and the nucleosynthesis in the central layers. Our results strongly suggest the pre-conditioning of the progenitor as a key-factor for our understanding of the diversity in SNeIa.
P. Hoeflich; J. Stein
Induction of Cytotoxicity by Photoexcited TiO2 Particles
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...TiO2 in the suspension was measured with combustion analysis. The TiO2 aqueous suspension...photoexcited TiO2 particles. it did not produce heat at the irradiated site. Since TiO2 alone...Heterogeneous photocatalytic oxidation of hydrocarbons on platinized TiO2 powders. J. Phys...
Ruxiong Cai; Yoshinobu Kubota; Taro Shuin; Hideki Sakai; Kazuhito Hashimoto; and Akira Fujishima
Reconstruction of Hessence Dark Energy and the Latest Type Ia Supernovae Gold Dataset
Recently, many efforts have been made to build dark energy models whose equation-of-state parameter can cross the so-called phantom divide $w_{de}=-1$. One of them is the so-called hessence dark energy model in which the role of dark energy is played by a non-canonical complex scalar field. In this work, we develop a simple method based on Hubble parameter $H(z)$ to reconstruct the hessence dark energy. As examples, we use two familiar parameterizations for $H(z)$ and fit them to the latest 182 type Ia supernovae Gold dataset. In the reconstruction, measurement errors are fully considered.
Hao Wei; Ningning Tang; Shuang Nan Zhang
Reconstruction of a Deceleration Parameter from the Latest Type Ia Supernovae Gold Dataset
In this paper, a parameterized deceleration parameter $q(z)= 1/2 - a/(1 + z)^b$ is reconstructed from the latest type Ia supernovae gold dataset. It is found out that the transition redshift from decelerated expansion to accelerated expansion is at $z_T=0.35^{+0.14}_{-0.07}$ with $1\\sigma$ confidence level in this parameterized deceleration parameter. And, the best fit values of parameters in $1\\sigma$ errors are $a=1.56^{+0.99}_{-0.55}$ and $b=3.82^{+3.70}_{-2.27}$.
Lixin Xu; Chengwu Zhang; Baorong Chang; Hongya Liu
On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae
The propagation of cellularly stabilized thermonuclear flames is investigated by means of numerical simulations. In Type Ia supernova explosions the corresponding burning regime establishes at scales below the Gibson length. The cellular flame stabilization - which is a result of an interplay between the Landau-Darrieus instability and a nonlinear stabilization mechanism - is studied for the case of propagation into quiescent fuel as well as interaction with vortical fuel flows. Our simulations indicate that in thermonuclear supernova explosions stable cellular flames develop around the Gibson scale and that deflagration-to-detonation transition is unlikely to be triggered from flame evolution effects here.
F. K. Roepke; W. Hillebrandt
Unbiased Estimate of Dark Energy Density from Type Ia Supernova Data
Science Journals Connector (OSTI)
Type Ia supernovae (SNe Ia) are currently the best probes of the dark energy in the universe. To constrain the nature of dark energy, we assume a flat universe and that the weak energy condition is satisfied, and we allow the density of dark energy, ?X(z), to be an arbitrary function of redshift. Using simulated data from a space-based SN pencil-beam survey, we find that by optimizing the number of parameters used to parameterize the dimensionless dark energy density, f(z) = ?X(z)/?X(z = 0), we can obtain an unbiased estimate of both f(z) and the fractional matter density of the universe, ?m. A plausible SN pencil-beam survey (with a square degree field of view and for an observational duration of 1 yr) can yield about 2000 SNe Ia with 0 ? z ? 2. Such a survey in space would yield SN peak luminosities with a combined intrinsic and observational dispersion of ?(mint) = 0.16 mag. We find that for such an idealized survey, ?m can be measured to 10% accuracy, and the dark energy density can be estimated to ~20% to z ~ 1.5, and ~20%-40% to z ~ 2, depending on the time dependence of the true dark energy density. Dark energy densities that vary more slowly can be more accurately measured. For the anticipated Supernova/Acceleration Probe (SNAP) mission, ?m can be measured to 14% accuracy, and the dark energy density can be estimated to ~20% to z ~ 1.2. Our results suggest that SNAP may gain much sensitivity to the time dependence of the dark energy density and ?m by devoting more observational time to the central pencil-beam fields to obtain more SNe Ia at z > 1.2. We use both a maximum likelihood analysis and a Monte Carlo analysis (when appropriate) to determine the errors of estimated parameters. We find that the Monte Carlo analysis gives a more accurate estimate of the dark energy density than the maximum likelihood analysis.
Yun Wang; Geoffrey Lovelace
One-dimensional delayed-detonation models of Type Ia supernovae: Confrontation to observations at bolometric maximum
The delayed-detonation explosion mechanism applied to a Chandrasekhar-mass white dwarf offers a very attractive model to explain the inferred characteristics of Type Ia supernovae (SNe Ia). The resulting ejecta are chemically stratified, have the same mass and roughly the same asymptotic kinetic energy, but exhibit a range in 56Ni mass. We investigate the contemporaneous photometric and spectroscopic properties of a sequence of delayed-detonation models, characterized by 56Ni masses between 0.18 and 0.81 Msun. Starting at 1d after explosion, we perform the full non-LTE, time-dependent radiative transfer with the code CMFGEN, with an accurate treatment of line blanketing, and compare our results to SNe Ia at bolometric maximum. Despite the 1D treatment, our approach delivers an excellent agreement to observations. We recover the range of SN Ia luminosities, colours, and spectral characteristics from the near-UV to 1 micron, for standard as well as low-luminosity 91bg-like SNe Ia. Our models predict an increase...
Blondin, Stķphane; Hillier, D John; Khokhlov, Alexei M
The p-Process in the Carbon Deflagration Model for Type Ia Supernovae and Chronology of the Solar System Formation
We study nucleosynthesis of p-nuclei in the carbon deflagration model for Type Ia supernovae (SNe Ia) by assuming that seed nuclei are produced by the s-process in accreting layers on a carbon-oxygen white dwarf during mass accretion from a binary companion. We find that about 50 % of the p-nuclides are synthesized in proportion to the solar abundance and that p-isotopes of Mo and Ru which are significantly underproduced in Type II supernovae (SNe II) are produced up to a level close to other p-nuclei. Comparing the yields of iron and p-nuclei in SNe Ia we find that SNe Ia can contribute to the galactic evolution of the p-nuclei. Next, we consider nucleochronology of the solar system formation by using four radioactive nuclides and apply the result of the p-process nucleosynthesis to simple galactic chemical evolution models. We find that when assumed three phases of interstellar medium are mixed by the interdiffusion with the timescale of about 40 Myr 53Mn/55Mn value in the early solar system is consistent with a meteoritic value. In addition, we put constraints to a scenario that SNe Ia induce the core collapse of the molecular cloud, which leads to the formation of the solar system.
Kusakabe, Motohiko [Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Iwamoto, Nobuyuki [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Nomoto, Ken'ichi [Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
Stable isotope-assisted NMR characterization of interaction between lipid A and sarcotoxin IA, a cecropin-type antibacterial peptide
Highlights: ? Recombinant sarcotoxin IA was successfully produced with {sup 13}C- and {sup 15}N-labeling. ? Sarcotoxin IA adopts an N-terminal ?-helix upon binding to lipid A-embedding micelles. ? Two lysine residues are involved in lipid A-mediated antibacterial activities. -- Abstract: Sarcotoxin IA is a 39-residue cecropin-type peptide from Sarcophaga peregrina. This peptide exhibits antibacterial activity against Gram-negative bacteria through its interaction with lipid A, a core component of lipopolysaccharides. To acquire detailed structural information on this specific interaction, we performed NMR analysis using bacterially expressed sarcotoxin IA analogs with {sup 13}C- and {sup 15}N-labeling along with lipid A-embedding micelles composed of dodecylphosphocholine. By inspecting the stable isotope-assisted NMR data, we revealed that the N-terminal segment (Leu3¢Arg18) of sarcotoxin IA formed an amphiphilic ?-helix upon its interaction with the aqueous micelles. Furthermore, chemical shift perturbation data indicated that the amino acid residues displayed on this ?-helix were involved in the specific interaction with lipid A. On the basis of these data, we successfully identified Lys4 and Lys5 as key residues in the interaction with lipid A and the consequent antibacterial activity. Therefore, these results provide unique information for designing chemotherapeutics based on antibacterial peptide structures.
Yagi-Utsumi, Maho [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan) [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan); Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); Yamaguchi, Yoshiki [Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan) [Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); Advanced Science Institute, RIKEN, Wako 351-0198 (Japan); Boonsri, Pornthip [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan) [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan); Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand); Iguchi, Takeshi [Bioscience Research Laboratory, Fujiya Co., Ltd., Hadano, Kanagawa 257-0031 (Japan)] [Bioscience Research Laboratory, Fujiya Co., Ltd., Hadano, Kanagawa 257-0031 (Japan); Okemoto, Kazuo [Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo 162-8640 (Japan)] [Department of Biochemistry and Cell Biology, National Institute of Infectious Disease, Tokyo 162-8640 (Japan); Natori, Shunji [National Institute of Agrobiological Sciences, Tsukuba 305-8602 (Japan)] [National Institute of Agrobiological Sciences, Tsukuba 305-8602 (Japan); Kato, Koichi, E-mail: firstname.lastname@example.com [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan) [Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787 (Japan); Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); The Glycoscience Institute, Ochanomizu University, Tokyo 135-0064 (Japan); GLYENCE Co., Ltd., Nagoya 474-0858 (Japan)
NbTiN Based SIS Multilayer Structures for SRF Applications
For the past three decades, bulk niobium has been the material of choice for SRF cavities applications. RF cavity performance is now approaching the theoretical limit for bulk niobium. For further improvement of RF cavity performance for future accelerator projects, Superconductor ? Insulator - Superconductor (SIS) multilayer structures (as recently proposed by Alex Gurevich) present the theoretical prospect to reach RF performance beyond bulk Nb, using thinly layered higher-Tc superconductors with enhanced Hc1. Jefferson Lab (JLab) is pursuing this approach with the development of NbTiN and AlN based multilayer SIS structures. This paper presents the results on the characteristics of NbTiN films and the first RF measurements on NbTiN-based multilayer structure on thick Nb films.
Valente, Anne-marie; Eremeev, Grigory; Phillips, H.; Reece, Charles; Spradlin, Joshua; Yang, Qiguang; Lukaszew, Rosa
Pulsed electrospark deposition of MAX phase Cr2AlC based coatings on titanium alloy
Science Journals Connector (OSTI)
Abstract Coatings with a high amount of MAX phase were obtained onto Ti substrate using the pulsed electrospark deposition (PED) technique and Cr2AlC electrode material (??). The structure and phase formation of the coatings generated at different modes were studied. It was found, that a layer of titanium carbide was formed during the initial stage of the deposition at the interface as a result of chemical reaction between Cr2AlC electrode and Ti substrate which further acts as a diffusion barrier.
E.I. Zamulaeva; E.A. Levashov; T.A. Sviridova; N.V. Shvyndina; M.I. Petrzhik
Inference for the dark energy equation of state using Type IA supernova data
The surprising discovery of an accelerating universe led cosmologists to posit the existence of "dark energy"--a mysterious energy field that permeates the universe. Understanding dark energy has become the central problem of modern cosmology. After describing the scientific background in depth, we formulate the task as a nonlinear inverse problem that expresses the comoving distance function in terms of the dark-energy equation of state. We present two classes of methods for making sharp statistical inferences about the equation of state from observations of Type Ia Supernovae (SNe). First, we derive a technique for testing hypotheses about the equation of state that requires no assumptions about its form and can distinguish among competing theories. Second, we present a framework for computing parametric and nonparametric estimators of the equation of state, with an associated assessment of uncertainty. Using our approach, we evaluate the strength of statistical evidence for various competing models of dark energy. Consistent with current studies, we find that with the available Type Ia SNe data, it is not possible to distinguish statistically among popular dark-energy models, and that, in particular, there is no support in the data for rejecting a cosmological constant. With much more supernova data likely to be available in coming years (e.g., from the DOE/NASA Joint Dark Energy Mission), we address the more interesting question of whether future data sets will have sufficient resolution to distinguish among competing theories.
Christopher Genovese; Peter Freeman; Larry Wasserman; Robert Nichol; Christopher Miller
Flame-driven deflagration-to-detonation transitions in Type Ia supernovae?
Although delayed detonation models of thermonuclear explosions of white dwarfs seem promising for reproducing Type Ia supernovae, the transition of the flame propagation mode from subsonic deflagration to supersonic detonation remains hypothetical. A potential instant for this transition to occur is the onset of the distributed burning regime, i.e. the moment when turbulence first affects the internal flame structure. Some studies of the burning microphysics indicate that a deflagration-to-detonation transition may be possible here, provided the turbulent intensities are strong enough. Consequently, the magnitude of turbulent velocity fluctuations generated by the deflagration flame is analyzed at the onset of the distributed burning regime in several three-dimensional simulations of deflagrations in thermonuclear supernovae. It is shown that the corresponding probability density functions fall off towards high turbulent velocity fluctuations much more slowly than a Gaussian distribution. Thus, values claimed to be necessary for triggering a detonation are likely to be found in sufficiently large patches of the flame. Although the microphysical evolution of the burning is not followed and a successful deflagration-to-detonation transition cannot be guaranteed from simulations presented here, the results still indicate that such events may be possible in Type Ia supernova explosions.
F. K. Roepke
Flame Evolution During Type Ia Supernovae and the Deflagration Phase in the Gravitationally Confined Detonation Scenario
We develop an improved method for tracking the nuclear flame during the deflagration phase of a Type Ia supernova, and apply it to study the variation in outcomes expected from the gravitationally confined detonation (GCD) paradigm. A simplified 3-stage burning model and a non-static ash state are integrated with an artificially thickened advection-diffusion-reaction (ADR) flame front in order to provide an accurate but highly efficient representation of the energy release and electron capture in and after the unresolvable flame. We demonstrate that both our ADR and energy release methods do not generate significant acoustic noise, as has been a problem with previous ADR-based schemes. We proceed to model aspects of the deflagration, particularly the role of buoyancy of the hot ash, and find that our methods are reasonably well-behaved with respect to numerical resolution. We show that if a detonation occurs in material swept up by the material ejected by the first rising bubble but gravitationally confined to the white dwarf (WD) surface (the GCD paradigm), the density structure of the WD at detonation is systematically correlated with the distance of the deflagration ignition point from the center of the star. Coupled to a suitably stochastic ignition process, this correlation may provide a plausible explanation for the variety of nickel masses seen in Type Ia Supernovae.
D. M. Townsley; A. C. Calder; S. M. Asida; I. R. Seitenzahl; F. Peng; N. Vladimirova; D. Q. Lamb; J. W. Truran
Constraining a bulk viscous matter-dominated cosmological model using SNe Ia, CMB and LSS
We present and constrain a cosmological model which component is a pressureless fluid with bulk viscosity as an explanation for the present accelerated expansion of the universe. We study the particular model of a constant bulk viscosity coefficient \\zeta_m. The possible values of \\zeta_m are constrained using the cosmological tests of SNe Ia Gold 2006 sample, the CMB shift parameter R from the three-year WMAP observations, the Baryon Acoustic Oscillation (BAO) peak A from the Sloan Digital Sky Survey (SDSS) and the Second Law of Thermodynamics (SLT). It was found that this model is in agreement with the SLT using only the SNe Ia test. However when the model is submitted to the three cosmological tests together (SNe+CMB+BAO) the results are: 1.- the model violates the SLT, 2.- predicts a value of H_0 \\approx 53 km sec^{-1} Mpc^{-1} for the Hubble constant, and 3.- we obtain a bad fit to data with a \\chi^2_{min} \\approx 400 (\\chi^2_{d.o.f.} \\approx 2.2). These results indicate that this model is ruled out by the observations.
Arturo Avelino; U. Nucamendi; F. S. Guzmßn
Parametrizing the transition to the phantom epoch with Supernovae Ia and Standard Rulers
The properties of some particular parametrizations of the dark energy Equation of State (EoS) are studied by using Supernovae Ia data (HST Cluster Supernova Survey) combined with Standard Ruler datasets (Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)). In this sense, we propose some parametrizations that may present a (fast) transition to a phantom dark energy EoS (where $w_{DE}<-1$) and compare the results with the $\\Lambda$CDM model. The best fit of the models is obtained by using Sne Ia and Standard Ruler datasets, which provides some information about whether the phantom transition may be supported by the observations. In this regard, the crossing of the phantom barrier is allowed statistically but the occurrence of a future singularity seems unlikely. Furthermore, the reconstruction of a (non-)canonical scalar field Lagrangian from the EoS parameter is studied, where shown that EoS parametrizations can be well reconstructed in terms of scalar fields.
Leanizbarrutia, Iker
Verifying the Cosmological Utility of Type Ia Supernovae:Implications of a Dispersion in the Ultraviolet Spectra
We analyze the mean rest-frame ultraviolet (UV) spectrum ofType Ia Supernovae(SNe) and its dispersion using high signal-to-noiseKeck-I/LRIS-B spectroscopyfor a sample of 36 events at intermediateredshift (z=0.5) discoveredby the Canada-France-Hawaii TelescopeSupernova Legacy Survey (SNLS). Weintroduce a new method for removinghost galaxy contamination in our spectra,exploiting the comprehensivephotometric coverage of the SNLS SNe and theirhost galaxies, therebyproviding the first quantitative view of the UV spectralproperties of alarge sample of distant SNe Ia. Although the mean SN Ia spectrumhas notevolved significantly over the past 40 percent of cosmic history,preciseevolutionary constraints are limited by the absence of acomparable sample ofhigh quality local spectra. The mean UV spectrum ofour z 0.5 SNe Ia and itsdispersion is tabulated for use in futureapplications. Within the high-redshiftsample, we discover significant UVspectral variations and exclude dust extinctionas the primary cause byexamining trends with the optical SN color. Although progenitormetallicity may drive some of these trends, the variations we see aremuchlarger than predicted in recent models and do not follow expectedpatterns.An interesting new result is a variation seen in the wavelengthof selected UVfeatures with phase. We also demonstrate systematicdifferences in the SN Iaspectral features with SN lightcurve width inboth the UV and the optical. Weshow that these intrinsic variations couldrepresent a statistical limitation in thefuture use of high-redshift SNeIa for precision cosmology. We conclude thatfurther detailed studies areneeded, both locally and at moderate redshift wherethe rest-frame UV canbe studied precisely, in order that future missions canconfidently beplanned to fully exploit SNe Ia as cosmological probes.
Ellis, R.S.; Sullivan, M.; Nugent, P.E.; Howell, D.A.; Gal-Yam,A.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; Carlberg, R.G.; Conley,A.; Fouchez, D.; Guy, J.; Hardin, D.; Hook, I.; Pain, R.; Perrett, K.; Pritchet, C.J.; Regnault, N.
Electrochemistry properties of multilayer TiN/Ti coatings on NiTi alloy for cardiac occluder application
-elasticity, thermal shape memory, high corrosion and fatigue resistance, make NiTi alloy especially suitableTi alloy is a subject of numerous recent studies to improve the material's corrosion resistance as well,b , D.Y. Zhang e a Center for Biomedical Materials and Tissue Engineering, Academy for Advanced
Zheng, Yufeng
Highly uniform bipolar resistive switching characteristics in TiO{sub 2}/BaTiO{sub 3}/TiO{sub 2} multilayer
Nanoscale multilayer structure TiO{sub 2}/BaTiO{sub 3}/TiO{sub 2} has been fabricated on Pt/Ti/SiO{sub 2}/Si substrate by chemical solution deposition method. Highly uniform bipolar resistive switching (BRS) characteristics have been observed in Pt/TiO{sub 2}/BaTiO{sub 3}/TiO{sub 2}/Pt cells. Analysis of the current-voltage relationship demonstrates that the space-charge-limited current conduction controlled by the localized oxygen vacancies should be important to the resistive switching behavior. X-ray photoelectron spectroscopy results indicated that oxygen vacancies in TiO{sub 2} play a crucial role in the resistive switching phenomenon and the introduced TiO{sub 2}/BaTiO{sub 3} interfaces result in the high uniformity of bipolar resistive switching characteristics.
Ma, W. J.; Zhang, X. Y.; Wang, Ying; Zheng, Yue, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China) [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China); Micro and Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China); Lin, S. P. [Micro and Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China) [Micro and Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China); Sino-French Institute of Nuclear Engineering and Technology, Zhuhai Campus, Sun Yat-Sen University, Zhuhai 519082 (China); Luo, J. M.; Wang, B., E-mail: email@example.com, E-mail: firstname.lastname@example.com [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China); Li, Z. X. [Micro and Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China)] [Micro and Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-Sen University, 510275 Guangzhou (China)
CIMAT, VIII Escuela de verano, 30 de julio -10 de ago* Introducci'on a la Geometr'ia de la Mec'ani*
conservativo. 18.Sea A(E) el 'area dentro de una curva de fase cerrada que corresponde a nive* *l de energ'ia Introducci'on a la Geometr'ia de la Mec'ani* *ca Cl'asica Problemas 13 - 19
Bor, Gil
NLE Websites -- All DOE Office Websites (Extended Search)
Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These spaces are dedicated for...
? decay of 40Ti and 41Ti and implication for solar-neutrino detection
Science Journals Connector (OSTI)
The ? decay of 40Ti and 41Ti was studied by measuring the ?-delayed proton and ? emission. The half-lives for 40Ti and 41Ti were determined to be 54(2) and 82(3) ms, respectively. The experimental ?-decay strengths are compared with shell-model calculations and results from other measurements. The integrated Gamow-Teller strengths for 40Ti and 41Ti were found to be quenched, compared to the calculations, by factors of 0.79(3) and 0.93(3), respectively. Based on the experimental 40Ti??-decay strength, the neutrino absorption cross section and induced neutrino event rates for 40Ar were determined to be 14.3(3)ū10-43?cm2 and 9.4▒0.2(stat)-1.6+1.3(syst) SNU, respectively.
W. Liu; M. Hellstr÷m; R. Collatz; J. Benlliure; L. Chulkov; D. Cortina Gil; F. Farget; H. Grawe; Z. Hu; N. Iwasa; M. Pf³tzner; A. Piechaczek; R. Raabe; I. Reusen; E. Roeckl; G. Vancraeynest; A. W÷hr
Patterned Growth of TiO2 Nanowires on Titanium Substrates Jong-Yoon Ha1;2
and short processing time utilizes the Ti foil both as a substrate and as a metal supply, thus eliminating transport methods. Adachi et al. have reported the synthesis of titania NWs using hydrothermal reactions, these methods typically require complex setups and processes, harsh environmental conditions, and extended
Lin, Liwei
Neutron Diffraction Residual Strain Tensor Measurements Within The Phase IA Weld Mock-up Plate P-5
Oak Ridge National Laboratory (ORNL) has worked with NRC and EPRI to apply neutron and X-ray diffraction methods to characterize the residual stresses in a number of dissimilar metal weld mockups and samples. The design of the Phase IA specimens aimed to enable stress measurements by several methods and computational modeling of the weld residual stresses. The partial groove in the 304L stainless steel plate was filled with weld beads of Alloy 82. A summary of the weld conditions for each plate is provided in Table 1. The plates were constrained along the long edges during and after welding by bolts with spring-loaded washers attached to the 1-inch thick Al backing plate. The purpose was to avoid stress relief due to bending of the welded stainless steel plate. The neutron diffraction method was one of the methods selected by EPRI for non-destructive through thickness strain and stress measurement. Four different plates (P-3 to P-6) were studied by neutron diffraction strain mapping, representing four different welding conditions. Through thickness neutron diffraction strain mappings at NRSF2 for the four plates and associated strain-free d-zero specimens involved measurement along seven lines across the weld and at six to seven depths. The mountings of each plate for neutron diffraction measurements were such that the diffraction vector was parallel to each of the three primary orthogonal directions of the plate: two in-plane directions, longitudinal and transverse, and the direction normal to the plate (shown in left figure within Table 1). From the three orthogonal strains for each location, the residual stresses along the three plate directions were calculated. The principal axes of the strain and stress tensors, however, need not necessarily align with the plate coordinate system. To explore this, plate P-5 was selected for examination of the possibility that the principal axes of strain are not along the sample coordinate system axes. If adequate data could be collected the goal would be to determine the strain tensor's orientation and magnitude of strain along each principle axis direction.
Hubbard, Camden R [ORNL
Characteristics of vanadia on the surface of V2O5/Ti-PILC catalyst for the reduction of \\{NOx\\} by NH3
Science Journals Connector (OSTI)
A series of vanadia catalysts impregnated on titania pillared interlayered clays (Ti-PILCs) were prepared to identify the characteristics of vanadia on the surface of Ti-PILC for the selective catalytic reduction (SCR) of NO by NH3. V2O5/Ti-PILC exhibited superior performance as a novel SCR catalyst compared to conventional catalysts including V2O5/TiO2 and V2O5/Al2O3. NO removal activity over the supported vanadia catalyst is strongly influenced by the structure of vanadia species on the catalyst surface. The structure of vanadia species on various supports including TiO2, Al2O3, and SiO2 along with Ti-PILC has been examined by XRD, NMR and Raman analyses for the comparative study. Increasing the content of vanadia up to the monolayer coverage of the surface of Ti-PILC catalyst enhanced the ratio of the polymerized surface vanadia species to the isolated ones. These results are well correlated with TOF of vanadia on the catalyst surface for the reduction of NO by NH3.
Ho Jeong Chae; In-Sik Nam; Sung-Won Ham; Suk Bong Hong
Type Ia supernova diversity: white dwarf central density as a secondary parameter in three-dimensional delayed detonation models
Science Journals Connector (OSTI)
......function of redshift. The standard model of SNe Ia relies on the nuclear fusion of the initial composition (predominantly 12C and 16O) of...generated from a Monte Carlo based algorithm. The primary input parameters are the number of the ignition kernels and the......
I. R. Seitenzahl; F. Ciaraldi-Schoolmann; F. K. R÷pke
EARLY RADIO AND X-RAY OBSERVATIONS OF THE YOUNGEST NEARBY TYPE Ia SUPERNOVA PTF 11kly (SN 2011fe)
On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M-dot {approx}<10{sup -8}(w/100 km s{sup -1}) M{sub sun} yr{sup -1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.
Horesh, Assaf; Kulkarni, S. R.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Fox, Derek B. [Astronomy and Astrophysics, Eberly College of Science, Pennsylvania State University, University Park, PA 16802 (United States); Quimby, Robert [IPMU, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba (Japan); Gal-Yam, Avishay [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Cenko, S. Bradley [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); De Bruyn, A. G. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, NL-7990 AA Dwingeloo (Netherlands); Kamble, Atish; Wijers, Ralph A. M. J. [Center for Gravitation and Cosmology, University of Wisconsin, Milwaukee, WI 53211 (United States); Van der Horst, Alexander J. [Universities Space Research Association, NSSTC, Huntsville, AL 35805 (United States); Kouveliotou, Chryssa [Space Science Office, VP-62, NASA-Marshall Space Flight Center, Huntsville, AL 35805 (United States); Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate [Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, Santa Barbara, CA 93117 (United States); Nugent, Peter E. [Computational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Gehrels, Neil [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others
Experto Universitario Java Enterprise Validacin e internacionalizacin 2012-2013 Depto. Ciencia de la Computacin e IA Spring
Experto Universitario Java Enterprise Validaci├│n e internacionalizaci├│n ┬® 2012-2013 Depto. Ciencia #12;Experto Universitario Java Enterprise Validaci├│n e internacionalizaci├│n ┬® 2012-2013 Depto. Ciencia Java Enterprise Validaci├│n e internacionalizaci├│n ┬® 2012-2013 Depto. Ciencia de la Computaci├│n e IA
Escolano, Francisco
TheThe ScienceScience ForumForum (as I(as I picturepicture itit)) Scholarly work
#12;Robotics TheThe ScienceScience ForumForum (as I(as I picturepicture itit)) Humanities Scholarly of photonics, robotics, telematics, dynamic physical rendering and intelligent sensors served as the basis to inspire four bestselling authors. The results are four short stories which paint amusing, thought
Torras, Carme
EXCELLENTIA CoLumbIA ENgINEErINg66 echanical engineers think about the design, construction, material proper-
responsibility for understanding how engines work, how buildings can be more efficiently built, and howHEALTH EXCELLENTIA CoLumbIA ENgINEErINg66 M echanical engineers think about the design the environment affects bridge architecture. They also apply their knowledge to the workings of the human body
Hone, James
ANALYSIS OF LIMIT CYCLE STABILITY IN A TAP-CHANGING TRANSFORMER V. Donde I.A. Hiskens
ANALYSIS OF LIMIT CYCLE STABILITY IN A TAP-CHANGING TRANSFORMER V. Donde I.A. Hiskens Department of transformer tap changing and load dynamics. Lin- earization of a Poincar┬┤e map is used to prove local of the region of attraction can then be obtained. 1. INTRODUCTION Interactions between tap-changing transformers
Hiskens, Ian A.
A Precision Photometric Comparison between SDSS-II and CSP Type Ia Supernova Data
Consistency between Carnegie Supernova Project (CSP) and SDSS-II supernova (SN) survey ugri measurements has been evaluated by comparing SDSS and CSP photometry for nine spectroscopically confirmed Type Ia supernova observed contemporaneously by both programs. The CSP data were transformed into the SDSS photometric system. Sources of systematic uncertainty have been identified, quantified, and shown to be at or below the 0.023 magnitude level in all bands. When all photometry for a given band is combined, we find average magnitude differences of equal to or less than 0.011 magnitudes in ugri, with rms scatter ranging from 0.043 to 0.077 magnitudes. The u band agreement is promising, with the caveat that only four of the nine supernovae are well-observed in u and these four exhibit an 0.038 magnitude supernova-to-supernova scatter in this filter.
Mosher, J; Corlies, L; Folatelli, G; Frieman, J; Holtzman, J; Jha, S W; Kessler, R; Marriner, J; Phillips, M M; Stritzinger, M; Morrell, N; Schneider, D P
Beyond the bubble catastrophe of Type Ia supernovae: Pulsating Reverse Detonation models
We describe a mechanism by which a failed deflagration of a Chandrasekhar-mass carbon-oxygen white dwarf can turn into a successful thermonuclear supernova explosion, without invoking an ad hoc high-density deflagration-detonation transition. Following a pulsating phase, an accretion shock develops above a core of 1 M_sun composed of carbon and oxygen, inducing a converging detonation. A three-dimensional simulation of the explosion produced a kinetic energy of 1.05E51 ergs and 0.70 M_sun of 56Ni, ejecting scarcely 0.01 M_sun of C-O moving at low velocities. The mechanism works under quite general conditions and is flexible enough to account for the diversity of normal Type Ia supernovae. In given conditions the detonation might not occur, which would reflect in peculiar signatures in the gamma and UV-wavelengths
Eduardo Bravo; Domingo Garcia-Senz
A PRECISION PHOTOMETRIC COMPARISON BETWEEN SDSS-II AND CSP TYPE Ia SUPERNOVA DATA
Consistency between Carnegie Supernova Project (CSP) and SDSS-II Supernova Survey ugri measurements has been evaluated by comparing Sloan Digital Sky Survey (SDSS) and CSP photometry for nine spectroscopically confirmed Type Ia supernova observed contemporaneously by both programs. The CSP data were transformed into the SDSS photometric system. Sources of systematic uncertainty have been identified, quantified, and shown to be at or below the 0.023 mag level in all bands. When all photometry for a given band is combined, we find average magnitude differences of equal to or less than 0.011 mag in ugri, with rms scatter ranging from 0.043 to 0.077 mag. The u-band agreement is promising, with the caveat that only four of the nine supernovae are well observed in u and these four exhibit an 0.038 mag supernova-to-supernova scatter in this filter.
Mosher, J.; Sako, M.; Corlies, L. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Folatelli, G. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Frieman, J.; Kessler, R. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Holtzman, J. [Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States); Jha, S. W. [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Marriner, J. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Phillips, M. M.; Morrell, N. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Stritzinger, M. [Oskar Klein Centre for Cosmo Particle Physics, AlbaNova University Center, 106 91 Stockholm (Sweden); Schneider, D. P., E-mail: firstname.lastname@example.com [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
A Precision Photometric Comparison between SDSS-II and CSP Type Ia Supernova Data
Consistency between Carnegie Supernova Project (CSP) and SDSS-II Supernova Survey ugri measurements has been evaluated by comparing Sloan Digital Sky Survey (SDSS) and CSP photometry for nine spectroscopically confirmed Type Ia supernova observed contemporaneously by both programs. The CSP data were transformed into the SDSS photometric system. Sources of systematic uncertainty have been identified, quantified, and shown to be at or below the 0.023 mag level in all bands. When all photometry for a given band is combined, we find average magnitude differences of equal to or less than 0.011 mag in ugri, with rms scatter ranging from 0.043 to 0.077 mag. The u-band agreement is promising, with the caveat that only four of the nine supernovae are well observed in u and these four exhibit an 0.038 mag supernova-to-supernova scatter in this filter.
Mosher, J.; /Pennsylvania U.; Sako, M.; /Pennsylvania U.; Corlies, L.; /Pennsylvania U. /Columbia U.; Folatelli, G.; /Tokyo U. /Carnegie Inst. Observ.; Frieman, J.; /Chicago U., KICP /Chicago U., Astron. Astrophys. Ctr.; Holtzman, J.; /New Mexico State U.; Jha, S.W.; /Rutgers U., Piscataway; Kessler, R.; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., KICP; Marriner, J.; /Fermilab; Phillips, M.M.; /Carnegie Inst. Observ.; Stritzinger, M.; /Aarhus U. /Stockholm U., OKC /Bohr Inst. /Carnegie Inst. Observ.
{chi}{sup 2} versus median statistics in supernova type Ia data analysis
In this paper we compare the performances of the {chi}{sup 2} and median likelihood analysis in the determination of cosmological constraints using type Ia supernovae data. We perform a statistical analysis using the 307 supernovae of the Union 2 compilation of the Supernova Cosmology Project and find that the {chi}{sup 2} statistical analysis yields tighter cosmological constraints than the median statistic if only supernovae data is taken into account. We also show that when additional measurements from the cosmic microwave background and baryonic acoustic oscillations are considered, the combined cosmological constraints are not strongly dependent on whether one applies the {chi}{sup 2} statistic or the median statistic to the supernovae data. This indicates that, when complementary information from other cosmological probes is taken into account, the performances of the {chi}{sup 2} and median statistics are very similar, demonstrating the robustness of the statistical analysis.
Barreira, A. [Centro de Fisica do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Avelino, P. P. [Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)
Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae
Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and laminar flame speed, S_L. We find that if S_L ~ u', where u' is the rms amplitude of turbulent velocity fluctuations, the local flame propagation speed does not significantly deviate from S_L even in the presence of velocity fluctuations on scales below the laminar flame thickness. This result is interpreted in the context of subgrid-scale modeling of supernova explosions and the mechanism for deflagration-detonation-transitions.
J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch
Initiation of the Detonation in the Gravitationally Confined Detonation Model of Type Ia Supernovae
Science Journals Connector (OSTI)
We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and therefore the most likely location, for initiation of a detonation in the GCD model.
Ivo R. Seitenzahl; Casey A. Meakin; Don Q. Lamb; James W. Truran
Study of the Detonation Phase in the Gravitationally Confined Detonation Model of Type Ia Supernovae
We study the gravitationally confined detonation (GCD) model of Type Ia supernovae through the detonation phase and into homologous expansion. In the GCD model, a detonation is triggered by the surface flow due to single point, off-center flame ignition in carbon-oxygen white dwarfs. The simulations are unique in terms of the degree to which non-idealized physics is used to treat the reactive flow, including weak reaction rates and a time dependent treatment of material in nuclear statistical equilibrium (NSE). Careful attention is paid to accurately calculating the final composition of material which is burned to NSE and frozen out in the rapid expansion following the passage of a detonation wave over the high density core of the white dwarf; and an efficient method for nucleosynthesis post-processing is developed which obviates the need for costly network calculations along tracer particle thermodynamic trajectories. Observational diagnostics are presented for the explosion models, including abundance stratifications and integrated yields. We find that for all of the ignition conditions studied here, a self regulating process comprised of neutronization and stellar expansion results in final \\iso{Ni}{56} masses of $\\sim$1.1\\msun. But, more energetic models result in larger total NSE and stable Fe peak yields. The total yield of intermediate mass elements is $\\sim0.1$\\msun and the explosion energies are all around 1.5$\\times10^{51}$ ergs. The explosion models are briefly compared to the inferred properties of recent Type Ia supernova observations. The potential for surface detonation models to produce lower luminosity (lower \\iso{Ni}{56} mass) supernovae is discussed.
Casey A. Meakin; Ivo Seitenzahl; Dean Townsley; George C. Jordan IV; James Truran; Don Lamb
Initiation of the detonation in the gravitationally confined detonation model of type Ia supernovae.
We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and therefore the most likely location, for initiation of a detonation in the GCD model.
Seitenzahl, I. R.; Meakin, C. A.; Lamb, D. Q.; Truran, J. W. (Physics); (Univ. of Chicago); (Max-Planck-Inst. for Astrophysics); (Univ. of Arizona)
Study of the detonation phase in the gravitationally confined detonation model of type Ia supernovae.
We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zeldovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and therefore the most likely location, for initiation of a detonation in the GCD model.
Meakin, C. A.; Seitenzahl, I.; Jordan, G. C.; Truran,, J.; Lamb, D.; Physics; Univ. of Chicago; Univ. of Arizona
NUCLEOSYNTHESIS IN TWO-DIMENSIONAL DELAYED DETONATION MODELS OF TYPE Ia SUPERNOVA EXPLOSIONS
For the explosion mechanism of Type Ia supernovae (SNe Ia), different scenarios have been suggested. In these, the propagation of the burning front through the exploding white dwarf (WD) star proceeds in different modes, and consequently imprints of the explosion model on the nucleosynthetic yields can be expected. The nucleosynthetic characteristics of various explosion mechanisms are explored based on three two-dimensional explosion simulations representing extreme cases: a pure turbulent deflagration, a delayed detonation following an approximately spherical ignition of the initial deflagration, and a delayed detonation arising from a highly asymmetric deflagration ignition. Apart from this initial condition, the deflagration stage is treated in a parameter-free approach. The detonation is initiated when the turbulent burning enters the distributed burning regime. This occurs at densities around 10{sup 7} g cm{sup -3}-relatively low as compared to existing nucleosynthesis studies for one-dimensional spherically symmetric models. The burning in these multidimensional models is different from that in one-dimensional simulations as the detonation wave propagates both into unburned material in the high-density region near the center of a WD and into the low-density region near the surface. Thus, the resulting yield is a mixture of different explosive burning products, from carbon-burning products at low densities to complete silicon-burning products at the highest densities, as well as electron-capture products synthesized at the deflagration stage. Detailed calculations of the nucleosynthesis in all three models are presented. In contrast to the deflagration model, the delayed detonations produce a characteristic layered structure and the yields largely satisfy constraints from Galactic chemical evolution. In the asymmetric delayed detonation model, the region filled with electron capture species (e.g., {sup 58}Ni, {sup 54}Fe) is within a shell, showing a large off-set, above the bulk of {sup 56}Ni distribution, while species produced by the detonation are distributed more spherically.
Maeda, K. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Roepke, F.K.; Fink, M.; Hillebrandt, W.; Travaglio, C. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching (Germany); Thielemann, F.-K., E-mail: firstname.lastname@example.com [Department Physik, Universitaet Basel, CH-4056 Basel (Switzerland)
INITIATION OF THE DETONATION IN THE GRAVITATIONALLY CONFINED DETONATION MODEL OF TYPE Ia SUPERNOVAE
We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and therefore the most likely location, for initiation of a detonation in the GCD model.
Seitenzahl, Ivo R. [Department of Physics, University of Chicago, Chicago, IL 60637 (United States); Meakin, Casey A.; Truran, James W. [Joint Institute for Nuclear Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Lamb, Don Q. [Center for Astrophysical Thermonuclear Flashes, University of Chicago, Chicago, IL 60637 (United States)
SN 2003du: Signatures of the Circumstellar Environment in a Normal Type Ia Supernova?
We present observations of the Type Ia supernova 2003du and report the detectionof an unusual, high-velocity component in the Ca II infrared triplet, similar tofeatures previously observed in SN 2000cx and SN 2001el. This feature exhibits a large expansion velocity (~18,000 km/s) which is nearly constant between -7 and +2 days relative to maximum light, and disappears shortly thereafter. Otherthan this feature, the spectral evolution and light curve resemble those of a normal SN Ia. We find that the Ca II feature can plausibly be caused by a dense shell formed when circumstellar material of solar abundance is overrun by the rapidly expanding outermost layers of the SN ejecta. Model calculations show that the optical and infrared spectra are remarkably unaffected by the circumstellar interaction. In particular, no hydrogen lines are detectable in either absorption or emission. The only qualitatively different features are the strong, high-velocity feature in the Ca II IR-triplet, and a somewhat weaker O I feature near 7,300 AA. The morphology and time evolution of these features provide an estimate for the amount of accumulated matter and an indication of the mixing in the dense shell. We apply these diagnostic tools to SN 2003du and infer that about 2 x 10^{-2} M_sun of solar abundance material may have accumulated in a circumstellar shell prior to the observations. Furthermore, the early light curve data imply that the circumstellar material was originally very close to the progenitor system, perhaps from an accretion disk, Roche lobe or common envelope.
C. L. Gerardy; P. Hoeflich; R. A. Fesen; G. H. Marion; K. Nomoto; R. Quimby; B. E. Schaefer; L. Wang; J. C. Wheeler
HELIUM-IGNITED VIOLENT MERGERS AS A UNIFIED MODEL FOR NORMAL AND RAPIDLY DECLINING TYPE Ia SUPERNOVAE
The progenitors of Type Ia supernovae (SNe Ia) are still unknown, despite significant progress during the past several years in theory and observations. Violent mergers of two carbon-oxygen (CO) white dwarfs (WDs) are a candidate scenario suggested to be responsible for at least a significant fraction of normal SNe Ia. Here, we simulate the merger of two CO WDs using a moving-mesh code that allows for the inclusion of thin helium (He) shells (0.01 M{sub Sun }) on top of the WDs at an unprecedented numerical resolution. The accretion of He onto the primary WD leads to the formation of a detonation in its He shell. This detonation propagates around the CO WD and sends a converging shock wave into its core, known to robustly trigger a second detonation, as in the well-known double-detonation scenario for He-accreting CO WDs. However, in contrast to that scenario where a massive He shell is required to form a detonation through thermal instability, here the He detonation is ignited dynamically. Accordingly the required He-shell mass is significantly smaller, and hence its burning products are unlikely to affect the optical display of the explosion. We show that this scenario, which works for CO primary WDs with CO- as well as He-WD companions, has the potential to explain the different brightness distributions, delay times, and relative rates of normal and fast declining SNe Ia. Finally, we discuss extensions to our unified merger model needed to obtain a comprehensive picture of the full observed diversity of SNe Ia.
Pakmor, R.; Springel, V. [Heidelberger Institut fuer Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Kromer, M. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Taubenberger, S. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)
Performance Degradation of TiN-and TiC-deposited AISI316 bipolar plates for proton exchange membrane fuel cells
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TiN and TiC were deposited on AISI316 bipolar plates for proton exchange membrane fuel cells (PEMFCs) and their effects on the corrosion resistance and overall cell performance were investigated. TiN with a Ti...
Hee Yeol Lee; Jae Woong Choi; Gil Ho Hwangģ
Ti-based composite coatings with gradient TiC x reinforcements on TC4 titanium alloy prepared by laser cladding
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TiC x -NiTi2/Ti cermet composite coatings C1 and C2 with gradient TiC x ...reinforcements were prepared on TC4 titanium alloy by laser cladding ...
ShuNv Liu; ZongDe Liu; Yang Wang; Peng Yue
Narrow band defect luminescence from Al-doped ZnO probed by scanning tunneling cathodoluminescence
Institute of Physics. Related Articles Effect of CdS film thickness on the photoexcited carrier lifetime of TiO2/CdS core-shell nanowires Appl. Phys. Lett. 99, 153111 (2011) Current underestimationNarrow band defect luminescence from Al-doped ZnO probed by scanning tunneling cathodoluminescence
Russell, Kasey
E-Print Network 3.0 - al2o3 fgm joints Sample Search Results
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5 . D-10587 Berlin Summary: to such kind of FGMs as: some ce- ramicceramic FGMs, i.e. TiCSiC, MoSi2Al2O3 and MoSi2SiC, and also some ce... the behavior of cracks in a graded...
Ann bay lodyans 1 / se Bryant Freeman ("Tonton Liben") ki pare ti liv sa a
Ian santi sa 11 ap manje a. Li pa menm di bonjou menm. Li di li konsa: "Granmoun, kote 2 pou m fe pou m al lakay Bondye?" Granmoun Ian we li malelve, li reponn: "Fe sa. Ou a twouve kay Bondye." Wout sa a mennen nan yon twou djab. Vwala, neg la... pou I rive lakay Bondye. Ti granmoun Ian di I menm bagay: "Fe sa." Msye a swiv menm wout la, e tchoup! Djab yo manje I menm jan. Le manman an pa we 2 pitit li yo, ke li sote. Tchikata, twazyem gason an, di: "Manman, kite m al we kote yo ye...
Freeman, Bryant C., ed.
Corrosion resistance and friction of sintered NdFeB coated with Ti/TiN multilayers
Corrosion resistance and friction of sintered NdFeB coated with Ti/TiN multilayers Yuanyuan Cheng Polarization Fretting corrosion Ti/TiN multilayers were deposited on sintered NdFeB by radio frequency magnetron sputtering. The film grain size decreased with the number of multilayers in the stack. Corrosion
Volinsky, Alex A.
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ALS Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU...
Fl³ssiger Wasserstoff als Kraftstoff
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Seit mehr als hundert Jahren stellen Kohlenwasserstoffe aus Roh÷l fast ausschlie▀lich die Basis f³r alle im Verkehr verwendeten Kraftstoffe dar. Ein Verkehr ohne Benutzung von Kraftstoffen auf Kohlenwasserstof...
Prof. Dr. Ing. habil. Walter Peschka
Howes et al. Reply to Comment on "Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas" arXiv:0711.4355
G. G. Howes; S. C. Cowley; W. Dorland; G. W. Hammett; E. Quataert; A. A. Schekochihin; T. Tatsuno
New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion years. These objects, which include 13 spectroscopically confirmed SNe Ia at z > 1, were discovered during 14 epochs of reimaging of the GOODS fields North and South over two years with the Advanced Camera for Surveys on HST. Together with a recalibration of our previous HST-discovered SNe Ia, the full sample of 23 SNe Ia at z > 1 provides the highest-redshift sample known. Combined with previous SN Ia datasets, we measured H(z) at discrete, uncorrelated epochs, reducing the uncertainty of H(z>1) from 50% to under 20%, strengthening the evidence for a cosmic jerk--the transition from deceleration in the past to acceleration in the present. The unique leverage of the HST high-redshift SNe Ia provides the first meaningful constraint on the dark energy equation-of-state parameter at z >1. The result remains consistent with a cosmological constant (w(z)=-1), and rules out rapidly evolving dark energy (dw/dz >>1). The defining property of dark energy, its negative pressure, appears to be present at z>1, in the epoch preceding acceleration, with ~98% confidence in our primary fit. Moreover, the z>1 sample-averaged spectral energy distribution is consistent with that of the typical SN Ia over the last 10 Gyr, indicating that any spectral evolution of the properties of SNe Ia with redshift is still below our detection threshold.
Adam G. Riess; Louis-Gregory Strolger; Stefano Casertano; Henry C. Ferguson; Bahram Mobasher; Ben Gold; Peter J. Challis; Alexei V. Filippenko; Saurabh Jha; Weidong Li; John Tonry; Ryan Foley; Robert P. Kirshner; Mark Dickinson; Emily MacDonald; Daniel Eisenstein; Mario Livio; Josh Younger; Chun Xu; Tomas Dahlen; Daniel Stern
Fabrication of TiO{sub 2} nanocrystallized glass
Nanocrystallization of rutile and anatase was observed in a CaO-B{sub 2}O{sub 3}-Bi{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-TiO{sub 2} crystallized glass. The color of the present crystallized glass was changed by the heat-treatment temperature, and x-ray diffraction (XRD) patterns of the crystallized glass show that the apparent color change is correlated with the formation of titania nanocrystallites. The particle size of crystallites observed in the transmission electron microscope image is comparable to that measured by XRD pattern. In addition, a large change of refractive index between the rutile particles and glass matrix, 0.8 or larger, was obtained. The present titania crystallized glass will be not only a photocatalytic material but also a promising candidate for random lasing devices.
Masai, Hirokazu; Fujiwara, Takumi; Mori, Hiroshi; Komatsu, Takayuki [Department of Applied Physics, Tohoku University, 6-6-05 Aoba, Sendai 980-8579 (Japan); Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan)
TI-30XA Calculator Tips. Calculator Memory. - To use the memory function, hit the STO key to store a number in either memory 1, 2, or 3. o To store the product ofĀ...
Owen Davis
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ALS ALS About ESnet Overview ESnet Staff Governance Our Network Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ CU Science DMZ Penn State & VTTI Science DMZ NOAA Science DMZ NERSC Science DMZ ALS Multi-facility Workflow LCLS ESnet Strategic Plan ESnet Organizational Chart ESnet History Science Requirements Careers Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: email@example.com Provide Web Site Feedback: email@example.com Science DMZ for ALS Many beamline scientists at Berkeley Lab's Advanced Light Source (ALS) are or will be experiencing slower network speeds because of instrument upgrades. These new instruments, or more specifically detectors, are
In-situ Spectroscopy of Water Oxidation at Ir Oxide Nanocluster Drivenby Visible TiOCr Charge-Transfer Chromophore in Mesoporous Silica
An all-inorganic photocatalytic unit consisting of a binuclear TiOCr charge-transfer chromophore coupled to an Ir oxide nanocluster has been assembled on the pore surface of mesoporous silica AlMCM-41. In situ FT-Raman and EPR spectroscopy of an aqueous suspension of the resulting IrxOy-TiCr-AlMCM-41 powder reveal the formation of superoxide species when exciting the Ti(IV)OCr(III) --> Ti(III)OCr(IV) metal-to-metal charge-transfer chromophore with visible light. Use of H218O confirms that the superoxide species originates from oxidation of water. Photolysis in the absence of persulfate acceptor leads to accumulation of Ti(III) instead. The results are explained by photocatalytic oxidation of water at Ir oxide nanoclusters followed by trapping of the evolving O2 by transient Ti(III) centers to yield superoxide. Given the flexibility to select donor metals with appropriate redox potential, photocatalytic units consisting of a binuclear charge-transfer chromophore coupled to a water oxidation catalyst shown here constitute a step towards thermodynamically efficient visible light water oxidation units.
Frei, Heinz; Han, Hongxian; Frei, Heinz
CP Tech Center I Iowa State University I 2711 S. Loop Dr. Suite 4700,Ames, IA 50010-8664 I 515-294-5798 FOR MORE INFORMATION
CP Tech Center I Iowa State University I 2711 S. Loop Dr. Suite 4700,Ames, IA 50010-8664 I 515 calcium sulfate in the form of hemihydrate (plaster) in the cement (false set) or the uncontrolled early
Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability
Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.
Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.
Comparison of the Legacy and Gold SnIa Dataset Constraints on Dark Energy Models
We have performed a comparative analysis of three recent and reliable SnIa datasets available in the literature: the Full Gold (FG) dataset (157 data points $0dataset (140 data points $0dataset (115 data points $0datasets are consistent with each other at the 95% confidence level, the latest (SNLS) dataset shows distinct trends which are not shared by the Gold datasets. We find that the best fit dynamical $w(z)$ obtained from the SNLS dataset does not cross the PDL $w=-1$ and remains above and close to the $w=-1$ line for the whole redshift range $0datasets (FG and TG) clearly crosses the PDL and departs significantly from the PDL $w=-1$ line while the LCDM parameter values are about $2\\sigma$ away from the best fit $w(z)$. In addition, the $(\\Omega_{0m},\\Omega_\\Lambda)$ parameters in a LCDM parametrization without a flat prior, fit by the SNLS dataset, favor the minimal flat LCDM concordance model. The corresponding fit with the Gold datasets mildly favors a closed universe and the flat LCDM parameter values are $1\\sigma - 2\\sigma$ away from the best fit $(\\Omega_{0m},\\Omega_\\Lambda)$.
S. Nesseris; L. Perivolaropoulos
Phenomenology for Supernova Ia Data Based on a New Cosmic Time
A new phenomenological theory for the expansion of our universe is presented. Because fundamental supporting theory is still in development, its discussion is not presented in this paper. The theory is based on a new algebraic expression for cosmic time G Rho t^2=3/32Pi, which correctly predicts the WMAP measured cosmological constants and the fundamental Hubble parameter H(t) for the expansion of the universe. A replacement for dark matter, called here "dark mass", is proposed which scales as with the expansion and incorporated. It does not react with ordinary matter, except gravitationally, and produces flat rotational curves for spiral galaxies. Also a new expression for the approaching velocity of radiation in a closed 3-sphere expanding universe is given that accounts for the early degrading negative approach of radiation for z > 1.7. The expression is v = Hr-c. Combining these three elements produces a luminosity distance dL that successfully predicts the apparent magnitude of exploding supernova Ia stars and even the new gamma ray bursts with no need for dark energy or acceleration of the expansion of the universe.
Charles B. Leffert
Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Deflagration to Detonation Density
We explore the effects of the deflagration to detonation transition (DDT) density on the production of Ni-56 in thermonuclear supernova explosions (type Ia supernovae). Within the DDT paradigm, the transition density sets the amount of expansion during the deflagration phase of the explosion and therefore the amount of nuclear statistical equilibrium (NSE) material produced. We employ a theoretical framework for a well-controlled statistical study of two-dimensional simulations of thermonuclear supernovae with randomized initial conditions that can, with a particular choice of transition density, produce a similar average and range of Ni-56 masses to those inferred from observations. Within this framework, we utilize a more realistic "simmered" white dwarf progenitor model with a flame model and energetics scheme to calculate the amount of Ni-56 and NSE material synthesized for a suite of simulated explosions in which the transition density is varied in the range 1-3x10^7 g/cc. We find a quadratic dependence ...
Jackson, Aaron P; Townsley, Dean M; Chamulak, David A; Brown, Edward F; Timmes, F X
A Test of Tully-Fisher Distance Estimates Using Cepheids and Type Ia Supernovae
We update and extend the results of Shanks (1997, MNRAS, 290, L77) by making a direct test of Tully-Fisher distance estimates to thirteen spiral galaxies with HST Cepheid distances and to ten spiral galaxies with Type Ia supernova (SNIa) distances. The results show that the Tully-Fisher distance moduli are too short with respect to the Cepheid distances by 0.46+-0.11mag and too short with respect to the SNIa distances by 0.49+-0.18mag. Combining the HST Cepheid and the best SNIa data suggests that, overall, previous Tully-Fisher distances at v~1000 kms-1 were too short by 0.43+-0.09mag, a result which is significant at the 4.6 sigma level. These data therefore indicate that previous Tully-Fisher distances should be revised upwards by 22+-5% implying, for example, a Virgo distance of 19.0+-1.8Mpc. The value of Ho from Tully-Fisher estimates is correspondingly revised downwards from Ho=84+-10kms-1Mpc-1 to Ho=69+-8kms-1Mpc-1. There is evidence that the Tully-Fisher relation at large distances is affected by Malmquist bias. In this case, we argue that Ho<50kms-1Mpc-1 cannot be ruled out by Tully-Fisher considerations.
T. Shanks
Parametrizing the transition to the phantom epoch with Supernovae Ia and Standard Rulers
The reconstruction of a (non)canonical scalar field Lagrangian from the dark energy Equation of State (EoS) parameter is studied, where it is shown that any EoS parametrization can be well reconstructed in terms of scalar fields. Several examples of EoS parameters are studied and the particular scalar field Lagrangian is reconstructed. Then, we propose some new parametrizations that may present a (fast) transition to a phantom dark energy EoS (where $w_{DE}dark energy EoS are studied by using supernovae Ia data (HST Cluster Supernova Survey) combined with Standard Ruler datasets [Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)] and its comparison with the $\\Lambda$CDM model is analyzed. Then, the best fit of the models is obtained, which provides some information about whether a phantom transition may be supported by the observations. In this regard, the crossing of the phantom barrier is allowed statistically but the occurrence of a future singularity seems unlikely.
Iker Leanizbarrutia; Diego Sßez-G¾mez
A POSSIBLE EVOLUTIONARY SCENARIO OF HIGHLY MAGNETIZED SUPER-CHANDRASEKHAR WHITE DWARFS: PROGENITORS OF PECULIAR TYPE Ia SUPERNOVAE
Several recently discovered peculiar Type Ia supernovae seem to demand an altogether new formation theory that might help explain the puzzling dissimilarities between them and the standard Type Ia supernovae. The most striking aspect of the observational analysis is the necessity of invoking super-Chandrasekhar white dwarfs having masses {approx}2.1-2.8 M{sub Sun }, M{sub Sun} being the mass of Sun, as their most probable progenitors. Strongly magnetized white dwarfs having super-Chandrasekhar masses have already been established as potential candidates for the progenitors of peculiar Type Ia supernovae. Owing to the Landau quantization of the underlying electron degenerate gas, theoretical results yielded the observationally inferred mass range. Here, we sketch a possible evolutionary scenario by which super-Chandrasekhar white dwarfs could be formed by accretion on to a commonly observed magnetized white dwarf, invoking the phenomenon of flux freezing. This opens multiple possible evolution scenarios ending in supernova explosions of super-Chandrasekhar white dwarfs having masses within the range stated above. We point out that our proposal has observational support, such as the recent discovery of a large number of magnetized white dwarfs by the Sloan Digital Sky Survey.
Das, Upasana; Mukhopadhyay, Banibrata [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Rao, A. R., E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India)
Type Ia Supernovae with Bi-Modal Explosions Are Common -- Possible Smoking Gun for Direct Collisions of White-Dwarfs
We discover clear doubly-peaked line profiles in 3 out of ~20 type Ia supernovae (SNe Ia) with high-quality nebular-phase spectra. The profiles are consistently present in three well-separated Co/Fe emission features. The two peaks are respectively blue-shifted and red-shifted relative to the host galaxies and are separated by ~5000 km/s. The doubly-peaked profiles directly reflect a bi-modal velocity distribution of the radioactive Ni56 in the ejecta that powers the emission of these SNe. Due to their random orientations, only a fraction of SNe with intrinsically bi-modal velocity distributions will appear as doubly-peaked spectra. Therefore SNe with intrinsic bi-modality are likely common, especially among the SNe in the low-luminosity (~40% of all SNe Ia) part on the Philips relation \\Delta m15(B) >~ 1.3. Bi-modality is naturally expected from direct collisions of white dwarfs (WDs) due to the detonation of both WDs and is demonstrated in a 3D 0.64 M_Sun-0.64 M_Sun WD collision simulation.
Dong, Subo; Kushnir, Doron; Prieto, Jose L
Three-Dimensional Simulations of the Deflagration Phase of the Gravitationally Confined Detonation Model of Type Ia Supernovae
We report the results of a series of three-dimensional (3-D) simulations of the deflagration phase of the gravitationally confined detonation mechanism for Type Ia supernovae. In this mechanism, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point opposite breakout on the stellar surface. We find that detonation conditions are robustly reached in our 3-D simulations for a range of initial conditions and resolutions. Detonation conditions are achieved as the result of an inwardly-directed jet that is produced by the compression of unburnt surface material when the surface flow collides with itself. A high-velocity outwardly-directed jet is also produced. The initial conditions explored in this paper lead to conditions at detonation that can be expected to produce large amounts of $^{56}$Ni and small amounts of intermediate mass elements. These particular simulations are therefore relevant only to high luminosity Type Ia supernovae. Recent observations of Type Ia supernovae imply a compositional structure that is qualitatively consistent with that expected from these simulations.
G C Jordan IV; R T Fisher; D M Townsley; A C Calder; C Graziani; S Asida; D Q Lamb; J W Truran
The Joint Efficient Dark-energy Investigation (JEDI): Measuring the cosmic expansion history from type Ia supernovae
JEDI (Joint Efficient Dark-energy Investigation) is a candidate implementation of the NASA-DOE Joint Dark Energy Mission (JDEM). JEDI will probe dark energy in three independent methods: (1) type Ia supernovae, (2) baryon acoustic oscillations, and (3) weak gravitational lensing. In an accompanying paper, an overall summary of the JEDI mission is given. In this paper, we present further details of the supernova component of JEDI. To derive model-independent constraints on dark energy, it is important to precisely measure the cosmic expansion history, H(z), in continuous redshift bins from z \\~ 0-2 (the redshift range in which dark energy is important). SNe Ia at z > 1 are not readily accessible from the ground because the bulk of their light has shifted into the near-infrared where the sky background is overwhelming; hence a space mission is required to probe dark energy using SNe. Because of its unique near-infrared wavelength coverage (0.8-4.2 microns), JEDI has the advantage of observing SNe Ia in the rest frame J band for the entire redshift range of 0 energy are discussed, with special emphasis on the improved precision afforded by the rest frame near-infrared data.
M. M. Phillips; Peter Garnavich; Yun Wang; David Branch; Edward Baron; Arlin Crotts; J. Craig Wheeler; Edward Cheng; Mario Hamuy; for the JEDI Team
E-Print Network 3.0 - avastart ti traumade Sample Search Results
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University of South Carolina Collection: Mathematics 15 Characterization of TiN, TiC and TiCN coatings on Ti50.6 at.% Ni alloy deposited by PIII and deposition technique...
E-Print Network 3.0 - amorphous ni-ti alloys Sample Search Results
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044103 (6pp) doi:10.10881748-604134044103 Summary: .10881748-604134044103 Ti-TiC-TiCDLC gradient nano-composite film on a biomedical NiTi alloy Yufeng Zheng1,2, Dong...
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ALS Beamlines Directory Print ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone
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ALS Beamlines Directory Print ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone
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ALS User Meeting Archives ALS User Meeting Archives Past User Meeting Agendas, Workshops, and Awards Year Agenda Workshops David A. Shirley (Science) Klaus Halbach (Instrumentation) Tim Renner (Service) 2012 2012 User Meeting Agenda 2012 User Meeting Workshops 2012 ALS User Meeting Awards Carl Percival, Dudley Shallcross, Craig Taatjes and David Osborn (Sandia), for making the first direct measurements of the reactions of Criegee intermediates, and showing that their impact on tropospheric chemistry and climate may be substantially greater than previously assumed. 2012 ALS User Meeting Awards Jeff Dickert and Simon Morton of Berkeley Lab's Physical Biosciences Division for the invention and implementation of the Compact Variable Collimator (CVC), which has led to a dramatic increase in productivity of protein crystallography.
Hacking als Grenz³berschreitung
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In der Vergangenheit hat es sich als n³tzlich erwiesen, am Anfang eines Vortrages erst einmal ein paar Worte zu dem Verein zu verlieren, in dessen Vorstand ich mitwirke. Der Chaos Computer Club (CCC) ist viele...
Frank Simon
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Staff Photo Print On May 14, 2013, members of ALS staff posed for a group photo in front of the dome. A hi-res version can be downloaded here. The last staff photo was taken in...
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Der Werkstoff Glas bezeichnet ein Schmelzprodukt, das in der Natur als erstarrte vulkanische Schmelze vorkommt und dem Mensch bereits vor 5000 Jahren f³r die Herstellung von Schmuck und Werkst³cken diente. Im ...
Constraints on dark energy with the LOSS SNĀIa sample
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......deceleration, constrain the evolution of dark energy (DE), and search for possible...et-al. 2013). Imminent or future surveys to gather large data sets at high redshift include the Dark Energy Survey (DES) and the Large Synoptic......
Mohan Ganeshalingam; Weidong Li; Alexei V. Filippenko
Fast Transporting ZnO¢TiO2 Coaxial Photoanodes for Dye-Sensitized Solar Cells Based on ALD-Modified SiO2 Aerogel Frameworks
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To circumvent this problem, we have explored here the idea of conformally coating the silica¢ZnO aerogel structures with very thin layers of more robust metal oxides such as Al2O3, ZrO2, or TiO2 to create doubly coaxial structures. ... J¢V characteristics of DSSCs featuring 25 ?m thick aerogel-based SiO2¢ZnO films compared to similar films with ca. 3 and 4 ┼ coatings of Al2O3 and TiO2, respectively: (a) light performance; (b) dark performance. ... Figure 7. Plot showing the effects of increased layers of TiO2 coats over 6 nm ZnO-coated silica aerogels with respect to charge lifetimes from OCVD measurements. ...
Vennesa O. Williams; Nak Cheon Jeong; Chaiya Prasittichai; Omar K. Farha; Michael J. Pellin; Joseph T. Hupp
Structure, Magnetism and Conductivity in Epitaxial Ti-doped ...
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Magnetism and Conductivity in Epitaxial Ti-doped -Fe2O3 Hematite: Experiment and density functional theory Structure, Magnetism and Conductivity in Epitaxial Ti-doped -Fe2O3...
Oxygen Vacancies and Ferromagnetism in CoxTi¢x¢y...
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Vacancies and Ferromagnetism in CoxTi¢x¢y. Oxygen Vacancies and Ferromagnetism in CoxTi¢x¢y. Abstract: Abstract: Cobalt-doped titanium dioxide, or CTO, has...
THE HUBBLE SPACE TELESCOPE CLUSTER SUPERNOVA SURVEY. III. CORRELATED PROPERTIES OF TYPE Ia SUPERNOVAE AND THEIR HOSTS AT 0.9 < z < 1.46
Using the sample of Type Ia supernovae (SNe Ia) discovered by the Hubble Space Telescope (HST) Cluster Supernova Survey and augmented with HST-observed SNe Ia in the Great Observatories Origins Deep Survey (GOODS) fields, we search for correlations between the properties of SNe and their host galaxies at high redshift. We use galaxy color and quantitative morphology to determine the red sequence in 25 clusters and develop a model to distinguish passively evolving early-type galaxies from star-forming galaxies in both clusters and the field. With this approach, we identify 6 SN Ia hosts that are early-type cluster members and 11 SN Ia hosts that are early-type field galaxies. We confirm for the first time at z > 0.9 that SNe Ia hosted by early-type galaxies brighten and fade more quickly than SNe Ia hosted by late-type galaxies. We also show that the two samples of hosts produce SNe Ia with similar color distributions. The relatively simple spectral energy distributions expected for passive galaxies enable us to measure stellar masses of early-type SN hosts. In combination with stellar mass estimates of late-type GOODS SN hosts from Thomson and Chary, we investigate the correlation of host mass with Hubble residual observed at lower redshifts. Although the sample is small and the uncertainties are large, a hint of this relation is found at z > 0.9. By simultaneously fitting the average cluster galaxy formation history and dust content to the red-sequence scatters, we show that the reddening of early-type cluster SN hosts is likely E(B - V) {approx}< 0.06. The similarity of the field and cluster early-type host samples suggests that field early-type galaxies that lie on the red sequence may also be minimally affected by dust. Hence, the early-type-hosted SNe Ia studied here occupy a more favorable environment to use as well-characterized high-redshift standard candles than other SNe Ia.
Meyers, J.; Barbary, K.; Fakhouri, H. K.; Goldhaber, G. [Department of Physics, University of California Berkeley, Berkeley, CA 94720 (United States); Aldering, G.; Faccioli, L.; Hsiao, E. [E.O. Lawrence Berkeley National Lab, 1 Cyclotron Rd., Berkeley, CA 94720 (United States); Barrientos, L. F. [Departmento de Astronomia, Pontificia Universidad Catolica de Chile, Santiago (Chile); Brodwin, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dawson, K. S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Deustua, S.; Fruchter, A. S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Doi, M.; Ihara, Y. [Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Eisenhardt, P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Gilbank, D. G. [Department of Physics and Astronomy, University Of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Hattori, T. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohaku Place, Hilo, HI 96720 (United States); Kashikawa, N., E-mail: email@example.com [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Collaboration: Supernova Cosmology Project; and others
PULSATING REVERSE DETONATION MODELS OF TYPE Ia SUPERNOVAE. I. DETONATION IGNITION
Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf (WD). Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabilized WD. One of the possibilities that have been invoked is that an inefficient deflagration leads to the pulsation of a Chandrasekhar-mass WD, followed by formation of an accretion shock around a carbon-oxygen rich core. The accretion shock confines the core and transforms kinetic energy from the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work we explore the robustness of the detonation ignition for different PRD models characterized by the amount of mass burned during the deflagration phase, M {sub defl}. The evolution of the WD up to the formation of the accretion shock has been followed with a three-dimensional hydrodynamical code with nuclear reactions turned off. We found that detonation conditions are achieved for a wide range of M {sub defl}. However, if the nuclear energy released during the deflagration phase is close to the WD binding energy ({approx}0.46 x 10{sup 51} erg {yields} M {sub defl} {approx} 0.30 M {sub sun}) the accretion shock cannot heat and confine the core efficiently and detonation conditions are not robustly achieved.
Bravo, Eduardo; GarcIa-Senz, Domingo [Department de FIsica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona (Spain)], E-mail: email@example.com, E-mail: email@example.com
A Three-Dimensional Picture of the Delayed-Detonation Model of Type Ia Supernovae
Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but this kind of models has been explored mainly in one dimension. Here we present new three-dimensional delayed detonation models in which the deflagraton-to-detonation transition (DDT) takes place in conditions like those favored by one-dimensional models. We have used a SPH code adapted to SNIa with algorithms devised to handle subsonic as well as supersonic combustion fronts. The starting point was a C-O white dwarf of 1.38 solar masses. When the average density on the flame surface reached 2-3x10^7 g/cm^3 a detonation was launched. The detonation wave processed more than 0.3 solar masses of carbon and oxygen, emptying the central regions of the ejecta of unburned fuel and raising its kinetic energy close to the fiducial 10^51 ergs expected from a healthy Type Ia supernova. The final amount of 56Ni synthesized also was in the correct range. However, the mass of carbon and oxygen ejected is still too high. The three-dimensional delayed detonation models explored here show an improvement over pure deflagration models, but they still fail to coincide with basic observational constraints. However, there are many aspects of the model that are still poorly known (geometry of flame ignition, mechanism of DDT, properties of detonation waves traversing a mixture of fuel and ashes). Therefore, it will be worth pursuing its exploration to see if a good SNIa model based on the three-dimensional delayed detonation scenario can be obtained.
Eduardo Bravo; Domingo Garcia-Senz
Timescale stretch parameterization of Type Ia supernova B-band light curves
R-band intensity measurements along the light curve of Type Ia supernovae discovered by the Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter the time-axis width factor w identically equal to s times (1+z). The data points are then individually aligned in the time-axis, normalized and K-corrected back to the rest frame, after which the nearly 1300 normalized intensity measurements are found to lie on a well-determined common rest-frame B-band curve which we call the ''composite curve.'' The same procedure is applied to 18 low-redshift Calan/Tololo SNe with Z < 0.11; these nearly 300 B-band photometry points are found to lie on the composite curve equally well. The SCP search technique produces several measurements before maximum light for each supernova. We demonstrate that the linear stretch factor, s, which parameterizes the light-curve timescale appears independent of z, and applies equally well to the declining and rising parts of the light curve. In fact, the B band template that best fits this composite curve fits the individual supernova photometry data when stretched by a factor s with chi 2/DoF {approx} 1, thus as well as any parameterization can, given the current data sets. The measurement of the data of explosion, however, is model dependent and not tightly constrained by the current data. We also demonstrate the 1 + z light-cure time-axis broadening expected from cosmological expansion. This argues strongly against alternative explanations, such as tired light, for the redshift of distant objects.
Goldhaber, G.; Groom, D.E.; Kim, A.; Aldering, G.; Astier, P.; Conley, A.; Deustua, S.E.; Ellis, R.; Fabbro, S.; Fruchter, A.S.; Goobar, A.; Hook, I.; Irwin, M.; Kim, M.; Knop, R.A.; Lidman, C.; McMahon, R.; Nugent, P.E.; Pain, R.; Panagia, N.; Pennypacker, C.R.; Perlmutter, S.; Ruiz-Lapuente, P.; Schaefer, B.; Walton, N.A.; York, T.
Exploring Cosmological Expansion Parametrizations with the Gold SnIa Dataset
We use the SnIa Gold dataset to compare LCDM with 10 representative parametrizations of the recent Hubble expansion history $H(z)$. For the comparison we use two statistical tests; the usual $\\chi_{min}^2$ which is insensitive to the parametrization number of parameters, and a statistic we call the p-test which depends on both the value of $\\chi_{min}^2$ and the number $n$ of the parametrization parameters. The p-test measures the confidence level to which the parameter values corresponding to LCDM are excluded from the viewpoint of the parametrization tested. For example, for a linear equation of state parametrization $w(z)=w_0 + w_1 z$ the LCDM parameter values ($w_0=-1$, $w_1=0$) are excluded at 75% confidence level. We use a flat prior and $\\Omega_{0m}=0.3$. All parametrizations tested are consistent with the Gold dataset at their best fit. According to both statistical tests, the worst fits among the 10 parametrizations, correspond to the Chaplygin gas, the brane world and the Cardassian parametrizations. The best fit is achieved by oscillating parametrizations which can exclude the parameter values corresponding to LCDM at 85% confidence level. Even though this level of significance does not provide a statistically significant exclusion of LCDM (it is less than $2\\sigma$) and does not by itself constitute conclusive evidence for oscillations in the cosmological expansion, when combined with similar independent recent evidence for oscillations coming from the CMB and matter power spectra it becomes an issue worth of further investigation.
R. Lazkoz; S. Nesseris; L. Perivolaropoulos
Co-doped Anatase TiO? Heteroepitaxy on Si(001)
Pure anatase TiO? and CoxTi?-x O? (0.01 < x < 0.04) epitaxial thin films were deposited by oxygen-plasma-assisted molecular beam epitaxy (OPA-MBE) on Si(001) for evaluation as a potential dilute magnetic semiconductor material suitable for Si-based spintronic devices. Epitaxial growth on Si(001) was facilitated by the deposition of ╝or Į ML Sr metal on the clean Si(001) surface to form an oxidation resistant silicide layer, followed by deposition of a thin SrTiO? buffer layer. Using Į ML Sr metal to form the silicide allowed the deposition of 10 ML SrTiO? without oxidation of the Si interface. Epitaxial anatase could be grown on this heterostructure, although use of the oxygen plasma during deposition resulted in significant SiO? formation. Pure anatase films consisted of epitaxial anatase surface particles on a continuous anatase film. For Co-doped films, Co segregation to surface particles of epitaxial anatase was observed by Auger electron spectroscopy and transmission electron microscopy (TEM); faceting of the particles was observed for low Co doping concentrations. Although no secondary phases containing Co were observed in Co-doped anatase films by x-ray diffraction or TEM, x-ray absorption near edge spectroscopy indicated Co was present in the films as a mixture of Co(0), Co(II), and Co(III). All samples were ferromagnetic at room temperature; for lower Co concentrations, the ferromagnetic remanence (9%) and coercive field (100 Oe) were similar to phase-pure Co:TiO? / LaAlO?. However, the presence of Co(0) under strongly oxidizing growth conditions known to oxidize the Si interface implies that under no deposition conditions can Co metal be eliminated while simultaneously protecting the Si interface from oxidation.
Kaspar, Tiffany C.; Droubay, Timothy C.; Wang, Chong M.; Heald, Steve M.; Lea, Alan S.; Chambers, Scott A.
TiSol | Open Energy Information
TiSol TiSol Jump to: navigation, search Name TiSol Place Pasadena, California Sector Solar Product California-based start up focused on the production of dye sensitized solar cells. Coordinates 29.690847┬░, -95.196308┬░ Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":29.690847,"lon":-95.196308,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Morphology, deformation, and defect structures of TiCr{sub 2} in Ti-Cr alloys
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.
Chen, K.C.; Allen, S.M.; Livingston, J.D.
Dampfdruckmessungen und Protonenresonanzuntersuchung an Hydriden der intermetallischen Phasen Ti2(Ni, Co) und Ti2(Ni, Fe)
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NMR and hydrogen equilibrium pressure measurements were performed on hydrides of the intermetallic compounds Ti2(Ni, Co) and Ti2(Ni, Fe). The following values of enthalpy ?H and entropy ?S for the formation of th...
Engelbert Tuscher; Kurt Hiebl; Helmut Bittner
Synthesis of Ti-based electrodes using Ti-salt flocculated sludge and their application in lithium-ion batteries
We report a simple strategy to synthesize the nanostructured TiO{sub 2} samples by a solid state reaction using Ti-salt flocculated sludge. The structure and morphology of the Ti-salt flocculated sludge, nanostructured TiO{sub 2} samples and pure commercial Aldrich TiO{sub 2} powder were characterized by powder X-ray diffraction and field emission scanning electron microscopy (FE-SEM). The electrochemical performances were evaluated in coin type cells. Nanostructured TiO{sub 2} samples, obtained by Ti-salt flocculated sludge shows a higher capacity and better cycling performances than pure commercial Aldrich TiO{sub 2} powder at the cutoff of 1.0¢2.5 V especially at high current rate. The enhanced cycling performance can be attributed to the facts that their high crystallinity and uniform nano-sized distribution.
Kang, Jungwon; Rai, Alok Kumar; Kim, Sungjin; Choi, Eunseok; Yoo, Insun [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of)] [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of); Kim, Jongho [School of Applied Chemical Engineering and the Research Institute for Catalysis, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of)] [School of Applied Chemical Engineering and the Research Institute for Catalysis, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of); Kim, Jaekook, E-mail: email@example.com [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of)] [Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of)
Band Offsets at the Epitaxial Anatase TiO2/n-SrTiO3(001) Interface...
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to measure valence band offsets at the epitaxial anatase TiO2(002)n-SrTiO3(001) heterojunction prepared by molecular beam epitaxy, Within experimental error, the valance band...
Carrier-Controlled Ferromagnetism in SrTiO3
Magnetotransport and superconducting properties are investigated for uniformly La-doped SrTiO3 films and GdTiO3/SrTiO3 heterostructures, respectively. GdTiO3/SrTiO3 interfaces exhibit a high-density 2D electron gas on the SrTiO3 side of the interface, while, for the SrTiO3 films, carriers are provided by the dopant atoms. Both types of samples exhibit ferromagnetism at low temperatures, as evidenced by a hysteresis in the magnetoresistance. For the uniformly doped SrTiO3 films, the Curie temperature is found to increase with doping and to coexist with superconductivity for carrier concentrations on the high-density side of the superconducting dome. The Curie temperature of the GdTiO3/SrTiO3 heterostructures scales with the thickness of the SrTiO3 quantum well. The results are used to construct a stability diagram for the ferromagnetic and superconducting phases of SrTiO3.
Moetakef, Pouya; Williams, James R.; Ouellette, Daniel G.; Kajdos, Adam P.; Goldhaber-Gordon, David; Allen, S. James; Stemmer, Susanne
Ab initio Molecular Dynamics and Elastic Properties of TiC and TiN Nanoparticles A. V. Postnikov and P. Entel
Ab initio Molecular Dynamics and Elastic Properties of TiC and TiN Nanoparticles A. V. Postnikov composition and compared to frozen phonon and molecular dynamics calculations for crystalline TiC and Ti range of frequencies, including the phonon band gap of pure crystalline TiC (near 15 THz). Similar
Entel, P.
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feed-image feed-image Digg: ALSBerkeleyLab Facebook Page: 208064938929 Flickr: advancedlightsource Twitter: ALSBerkeleyLab YouTube: AdvancedLightSource Home About the ALS ALS in the News ALS in the News Roman Seawater Concrete Holds the Secret to Cutting Carbon Emissions Print Tuesday, 04 June 2013 00:00 An international team led by Paulo Monteiro of the Advanced Light Source and UC Berkeley has analyzed samples of Roman concrete from harbor installations that have survived 2,000 years of chemical attack and wave action, "one of the most durable construction materials on the planet," says UC Berkeley's Marie Jackson, a leading member of the team. Says Monteiro, "It's not that modern concrete isn't good, but manufacturing Portland cement accounts for seven percent of the carbon dioxide that industry puts into the air." The carbon footprint of Roman concrete, made from lime, volcanic ash, and seawater, is much smaller.
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Beamlines Directory Beamlines Directory ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone
Unusual activation of novel Au/TiO2/AI2O3 xH2O catalysts by calcination
Au/Al{sub 2}O{sub 3} {center_dot} xH{sub 2}O and Au/TiO{sub 2}/Al{sub 2}O{sub 3} {center_dot} xH{sub 2}O (x = 0-3) catalysts were prepared by assembling gold nanoparticles on neat and TiO{sub 2}-modified Al{sub 2}O{sub 3}, AlOOH, and Al(OH){sub 3} supports, and their catalytic activity in CO oxidation was tested either as synthesized or after on-line pretreatment in O{sub 2}-He at 500 C. A promotional effect of TiO{sub 2} on the activity of gold catalysts was observed upon 500 C-pretreatment. The catalyst stability as a function of time on stream was tested in the absence or presence of H{sub 2}, and physiochemical characterization applying BET, ICP-OES, XRD, TEM, and {sup 27}Al MAS NMR was conducted.
Yan, Wenfu [ORNL; Ma, Zhen [ORNL; Mahurin, Shannon Mark [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL
Reaction Mechanisms in the Li3AlH6/LiBH4 and Al/LiBH4 Systems for Reversible Hydrogen Storage. Part 1: H capacity and Role of Al
Lithium-based complex hydrides, including lithium aluminum hydrides (LiAlH4, Li3AlH6) and lithium borohydride (LiBH4), are some of the most attractive materials for hydrogen storage due to their high hydrogen contents. In the present work, we investigated the hydrogen storage properties of combined systems of Li3AlH6-LiBH4 and Al-LiBH4, both of which exhibit favorable hydrogen storage properties owing to the formation of AlB2 during dehydrogenation. TGA data showed that TiCl3-doped Li3AlH6/2LiBH4 and 0.5Al/LiBH4 release ~ 8.8 and ~ 8.4 wt.% H2, respectively, with ~ 3.8 and ~ 5.8 wt.% release after rehydrogenation of the dehydrogenation product. XRD results identified LiH and AlB2 phases in the dehydrogenated products, which has suggested a mechanism by which Al contributes to the remarkable improvement of the reversible storage properties of LiBH4 in terms of the temperature and pressure for H2 release/uptake.
Choi, Young Joon; Lu, Jun; Sohn, Hong Yong; Fang, Zhigang Zak
Effects of preformed alumina scales on the behavior of FeCrAl alloys in simulated coal-gasifier atmospheres
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Iron-based mechanical alloys containing 3.2¢6.6 Al, 16.0¢24.7 Cr, 0.5 Ti, and 0.5 Y2O3 (mass%) were preoxidized in air at 1373 K for 10¢180 min. Alumina scales were formed. Scales were isolated and examined in a ...
J. K. Richard Weber; M. G. Hocking
Table 2 -Lime use and practices on Corn, major producing states, 2001 CO GA IL IN IA KS KY MI MN MO NE NY NC ND OH PA SD TX WI Area
Table 2 - Lime use and practices on Corn, major producing states, 2001 CO GA IL IN IA KS KY MI MN.7 Table 2 - Lime use and practices on Corn, major producing states, 2000 CO IL IN IA KS KY MI MN MO NE NY use and practices on Corn, major producing states, 1999 CO IL IN IA KS KY MI MN MO NE NC OH SD TX WI
Kammen, Daniel M.
Brambilla, et al. Reply: van Megen and Williams (vMW) question our recent claim that dense colloidal hard spheres enter at large volume fraction \\phi a dynamical regime not observed in earlier work and not described by the mode-coupling theory (MCT) of the glass transition.
Giovanni Brambilla; Djamel El Masri; Matteo Pierno; Ludovic Berthier; Luca Cipelletti; George Petekidis; Andrew B. Schofield
Fisica Geral IA (2010/1) Nome 1 2 3 R1 R2 R3 Media Conc
Fisica Geral IA (2010/1) Nome 1 2 3 R1 R2 R3 M┬┤edia Conc 1 ANDERSON SILVEIRA SALDANHA 0.5 5.2 4.7 0.7 3.5 4.5 1.5 - - 3.57 D M┬┤edia 2.60 4.64 5.93 5.54 6.08 8.37 4.60 #12;20 40 60 80 100 A B C D FF 23
Stariolo, Daniel Adri├Īn
Eine analytische Brennstoffzelle als Alkoholsensor
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Es wird eine analytische Brennstoffzelle zur quantitativen Bestimmung von Alkoholen beschrieben. Als...
H. Huck
Smith et al Supporting Information
Smith et al 1 Supporting Information for Smith et al. 2006, PLoS Computational Biology 2:e161-hyperpallium apicale; HF-hippocampal formation, and M-mesopallium. #12;Smith et al 2 FigureS2,nolinkswerefoundbetweenelectrodesindifferentbirds,andnolinkswerefoundintothesoundstimulusvariable. CombinedAnalysisofAllBirds'ElectrodesPlusSound #12;Smith et al 3 Analysis of Data from Subsections
Jarvis, Erich D.
Combustion synthesis/quasi-isostatic pressing of TiC0.7NiTi cermets: microstructure and transformation characteristics
Combustion synthesis/quasi-isostatic pressing of TiC0.7┬ŁNiTi cermets: microstructure Abstract TiC0.7┬ŁNiTi cermets were produced by com- bustion synthesis followed by quasi-isostatic consolidation while the reaction products were still hot and ductile. The TiC0.7┬ŁNiTi cermets were characterized
Meyers, Marc A.
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Beamlines Directory Print Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone
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User Meeting Archives Print User Meeting Archives Print Past User Meeting Agendas, Workshops, and Awards Year Agenda Workshops David A. Shirley (Science) Klaus Halbach (Instrumentation) Tim Renner (Service) 2012 2012 User Meeting Agenda 2012 User Meeting Workshops 2012 ALS User Meeting Awards Carl Percival, Dudley Shallcross, Craig Taatjes and David Osborn (Sandia), for making the first direct measurements of the reactions of Criegee intermediates, and showing that their impact on tropospheric chemistry and climate may be substantially greater than previously assumed. 2012 ALS User Meeting Awards Jeff Dickert and Simon Morton of Berkeley Lab's Physical Biosciences Division for the invention and implementation of the Compact Variable Collimator (CVC), which has led to a dramatic increase in productivity of protein crystallography.
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Beamlines Directory Print Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone
First detection of $^{56}$Co gamma-ray lines from type Ia supernova (SN2014J) with INTEGRAL
We report the first ever detection of $^{56}$Co lines at 847 and 1237 keV and a continuum in the 200-400 keV band from the Type Ia supernova SN2014J in M82 with INTEGRAL observatory. The data were taken between 50th and 100th day since the SN2014J outburst. The line fluxes suggest that $0.62\\pm0.13~M\\odot$ of radioactive $^{56}$Ni were synthesized during the explosion. Line broadening gives a characteristic ejecta expansion velocity $V_e\\sim 2100\\pm 500~{\\rm km~s^{-1}}$. The flux at lower energies (200-400 keV) flux is consistent with the three-photon positronium annihilation, Compton downscattering and absorption in the $\\sim~1.4~M\\odot$ ejecta composed from equal fractions of iron-group and intermediate-mass elements and a kinetic energy $E_k\\sim 1.4~10^{51}~{\\rm erg}$. All these parameters are in broad agreement with a "canonical" model of an explosion of a Chandrasekhar-mass White Dwarf (WD), providing an unambiguous proof of the nature of Type Ia supernovae as a thermonuclear explosion of a solar mass co...
Churazov, E; Isern, J; Kn÷dlseder, J; Jean, P; Lebrun, F; Chugai, N; Grebenev, S; Bravo, E; Sazonov, S; Renaud, M
Chasing the phantom: A closer look at type Ia supernovae and the dark energy equation of state
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Some recent observations provide >2? evidence for phantom dark energyŚa value of the dark energy equation of state less than the cosmological-constant value of ?1. We focus on constraining the equation of state by combining current data from the most mature geometrical probes of dark energy: type Ia supernovae (SNe Ia) from the Supernova Legacy Survey (SNLS3), the Supernova Cosmology Project (Union2.1), and the Pan-STARRS1 survey (PS1); cosmic microwave background measurements from Planck and WMAP9; and a combination of measurements of baryon acoustic oscillations. The combined data are consistent with w=?1 for the Union2.1 sample, though they present moderate (?1.9?) evidence for a phantom value when either the SNLS3 or PS1 sample is used instead. We study the dependence of the constraints on the redshift, stretch, color, and host galaxy stellar mass of SNe, but we find no unusual trends. In contrast, the constraints strongly depend on any external H0 prior: a higher adopted value for the direct measurement of the Hubble constant (H0?71??km/s/Mpc) leads to ?2? evidence for phantom dark energy. Given Planck data, we can therefore make the following statement at 2? confidence: either the SNLS3 and PS1 data have systematics that remain unaccounted for or the Hubble constant is below 71??km/s/Mpc; else the dark energy equation of state is indeed phantom.
Daniel L. Shafer and Dragan Huterer
Effect of reinforcing particle type on morphology and age-hardening behavior of Al¢4.5 wt.% Cu based nanocomposites synthesized through mechanical milling
The effects of reinforcing particle type (SiC and TiC) on morphology and precipitation hardening behavior of Al¢4.5%Cu based nanocomposites synthesized via mechanical milling were investigated in the current work. In order to study the microstructure and morphology of mechanically milled powder, X-ray diffraction technique, scanning electron microscopy and high resolution transmission electron microscopy were utilized. Results revealed that at the early stages of mechanical milling, when reinforcing particles are polycrystal, the alloying process is enhanced more in the case of using the TiC particles as reinforcement. But, at the final stages of mechanical milling, when reinforcing particles are single crystal, the alloying process is enhanced more in the case of using the SiC ones. Transmission electron microscopy results demonstrated that Al¢4.5 wt.%Cu based nanocomposite powders were synthesized and confirmed that the mutual diffusion of aluminum and copper occurs through the interfacial plane of (200). The hardness results showed that not only does introducing 4 vol.% of reinforcing particles (SiC or TiC) considerably decrease the porosity of the bulk composite samples, but also it approximately doubles the hardness of Al¢4.5 wt.%Cu alloy (53.4 HB). Finally, apart from TEM and scanning electron microscopy observation which are localized, a decline in hardness in the TiC and SiC contained samples, respectively, after 1.5 and 2 h aging time at 473 K proves the fact that the size of SiC particles is smaller than the size of the TiC ones. - Highlights: ? HRTEM results show mutual diffusion of Al and Cu occurs through the (200) planes. ? TiC particles enhance alloying process more than the SiC ones at the early stages of MM. ? SiC particles enhance alloying process more than the TiC ones at the final stages of MM.
Mostaed, A., E-mail: email@example.com [Advanced Materials and Nanotechnology Research Center, Faculty of Mechanical Engineering, K.N. Toosi University of Technology, 16765-3381 Pardis Street, Tehran (Iran, Islamic Republic of); Saghafian, H.; Mostaed, E. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Narmak, Tehran (Iran, Islamic Republic of); Shokuhfar, A. [Advanced Materials and Nanotechnology Research Center, Faculty of Mechanical Engineering, K.N. Toosi University of Technology, 16765-3381 Pardis Street, Tehran (Iran, Islamic Republic of); Rezaie, H.R. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Narmak, Tehran (Iran, Islamic Republic of)
Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution
We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to provide the first conclusive evidence for cosmic deceleration that preceded the current epoch of cosmic acceleration. These objects, discovered during the course of the GOODS ACS Treasury program, include 6 of the 7 highest-redshift SNe Ia known, all at z>1.25, and populate the Hubble diagram in unexplored territory. The luminosity distances to these and 170 previous SNe Ia are provided. A purely kinematic interpretation of the SN Ia sample provides evidence at the > 99% confidence level for a transition from deceleration to acceleration or similarly, strong evidence for a cosmic jerk. Using a simple model of the expansion history, the transition between the two epochs is constrained to be at z=0.46 +/- 0.13. The data are consistent with the cosmic concordance model of Omega_M ~ 0.3, Omega_Lambda~0.7 (chi^2_dof=1.06), and are inconsistent with a simple model of evolution or dust as an alternative to dark energy. For a flat Universe with a cosmological constant. When combined with external flat-Universe constraints we find w=-1.02 + 0.13 - 0.19 (and $dark energy, P = w\\rho c^2. Joint constraints on both the recent equation of state of dark energy, $w_0$, and its time evolution, dw/dz, are a factor of ~8 more precise than its first estimate and twice as precise as those without the SNe Ia discovered with HST. Our constraints are consistent with the static nature of and value of w expected for a cosmological constant (i.e., w_0 = -1.0, dw/dz = 0), and are inconsistent with very rapid evolution of dark energy. We address consequences of evolving dark energy for the fate of the Universe.
Adam G. Riess; Louis-Gregory Strolger; John Tonry; Stefano Casertano; Henry C. Ferguson; Bahram Mobasher; Peter Challis; Alexei V. Filippenko; Saurabh Jha; Weidong Li; Ryan Chornock; Robert P. Kirshner; Bruno Leibundgut; Mark Dickinson; Mario Livio; Mauro Giavalisco; Charles C. Steidel; Narciso Benitez; Zlatan Tsvetanov
Failed-detonation Supernovae: Subluminous Low-velocity Ia Supernovae and their Kicked Remnant White Dwarfs with Iron-rich Cores
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Type Ia supernovae (SNe Ia) originate from the thermonuclear explosions of carbon-oxygen (C-O) white dwarfs (WDs). The single-degenerate scenario is a well-explored model of SNe Ia where unstable thermonuclear burning initiates in an accreting, Chandrasekhar-mass WD and forms an advancing flame. By several proposed physical processes, the rising, burning material triggers a detonation, which subsequently consumes and unbinds the WD. However, if a detonation is not triggered and the deflagration is too weak to unbind the star, a completely different scenario unfolds. We explore the failure of the gravitationally confined detonation mechanism of SNe Ia, and demonstrate through two-dimensional and three-dimensional simulations the properties of failed-detonation SNe. We show that failed-detonation SNe expel a few 0.1 M ? of burned and partially burned material and that a fraction of the material falls back onto the WD, polluting the remnant WD with intermediate-mass and iron-group elements that likely segregate to the core forming a WD whose core is iron rich. The remaining material is asymmetrically ejected at velocities comparable to the escape velocity from the WD, and in response, the WD is kicked to velocities of a few hundred km s¢1. These kicks may unbind the binary and eject a runaway/hypervelocity WD. Although the energy and ejected mass of the failed-detonation SN are a fraction of typical thermonuclear SNe, they are likely to appear as subluminous low-velocity SNe Ia. Such failed detonations might therefore explain or are related to the observed branch of peculiar SNe Ia, such as the family of low-velocity subluminous SNe (SN 2002cx/SN 2008ha-like SNe).
George C. Jordan, IV; Hagai B. Perets; Robert T. Fisher; Daniel R. van Rossum
FAILED-DETONATION SUPERNOVAE: SUBLUMINOUS LOW-VELOCITY Ia SUPERNOVAE AND THEIR KICKED REMNANT WHITE DWARFS WITH IRON-RICH CORES
Type Ia supernovae (SNe Ia) originate from the thermonuclear explosions of carbon-oxygen (C-O) white dwarfs (WDs). The single-degenerate scenario is a well-explored model of SNe Ia where unstable thermonuclear burning initiates in an accreting, Chandrasekhar-mass WD and forms an advancing flame. By several proposed physical processes, the rising, burning material triggers a detonation, which subsequently consumes and unbinds the WD. However, if a detonation is not triggered and the deflagration is too weak to unbind the star, a completely different scenario unfolds. We explore the failure of the gravitationally confined detonation mechanism of SNe Ia, and demonstrate through two-dimensional and three-dimensional simulations the properties of failed-detonation SNe. We show that failed-detonation SNe expel a few 0.1 M{sub Sun} of burned and partially burned material and that a fraction of the material falls back onto the WD, polluting the remnant WD with intermediate-mass and iron-group elements that likely segregate to the core forming a WD whose core is iron rich. The remaining material is asymmetrically ejected at velocities comparable to the escape velocity from the WD, and in response, the WD is kicked to velocities of a few hundred km s{sup -1}. These kicks may unbind the binary and eject a runaway/hypervelocity WD. Although the energy and ejected mass of the failed-detonation SN are a fraction of typical thermonuclear SNe, they are likely to appear as subluminous low-velocity SNe Ia. Such failed detonations might therefore explain or are related to the observed branch of peculiar SNe Ia, such as the family of low-velocity subluminous SNe (SN 2002cx/SN 2008ha-like SNe).
Jordan, George C. IV; Van Rossum, Daniel R. [Center for Astrophysical Thermonuclear Flashes, University of Chicago, Chicago, IL 60637 (United States); Perets, Hagai B. [Physics Department, Technion, Israel Institute of Technology, Haifa 32000 (Israel); Fisher, Robert T. [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States)
He H`ike no ka Ho`opihapiha `ia o ka Pepa Noi Komo no ka Papahana Ho`omkaukau Kumu `iwi `o Kahuawaiola
45 a `oi ma ka pae 300 a ma luna a`e paha a e k ana n koina `lelo a mo`omeheu Hawai`i e helu `ia nei`omeheu Hawai`i. 7. ka puka `ana ma ho`okahi o n papa penei: HWST 205, 471, 472, 473, 474; a i `ole ka `ae a ka `ekolu kau kona l`ihi i kkulu `ia no ka ho`omkaukau `ana i n kumu Mauli Ola Hawai`i no ka ho`ona`auao ma
Wiegner, Tracy N.
Towards electrical spin injection into LaAlO3¢SrTiO3
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...their remarkable multi-functional and...already provide such building blocks for charge-based...found in the oxides family (e.g. superconductivity...from the outstanding multi-functional properties...their remarkable multi-functional and...already provide such building blocks for charge-based...
E-Print Network 3.0 - alloys sistema ti-al-mo Sample Search Results
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89 the machinist mar 2007 agnesium is 36 per cent Summary: alloys. Reducing the automobile weights by certain amount will result in similar percentage... a combination of...
XPS Analysis of Ti6Al4V Oxidation Under UHV Conditions
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An alternative strategy to study the distribution of oxides in the passive layer is to monitor their growth directly on the metal surface. For this, previous oxide layers are removed by sputtering to obtain clean...
M. Hierro-Oliva; A. M. Gallardo-Morenoģ
Thermodynamic Instability at the Stoichiometric LaAlO3/SrTiO3...
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Instruments: Ultra-high Vacuum, Low-temperature Scanning Probe Microscope Instrument, or UHV LT SPM Tags: Nanoscope IIIa topographical nanostructures nanodevices oxides catalysis...
Optical Monitoring in Laser Cladding of Ti6Al4V
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The TRUMPF 505 DMD machine with a 5-kW CO2 laser was used to enable scaling-up laser cladding (LC) to an industrial level. The ... powder. The variations of brightness temperature versus laser power and cladding ...
I. Smurov; M. Doubenskaia; S. Grigoriev; A. Nazarov
Photocatalytic H2 production from ethanol over Au/TiO2 and Ag/TiO2
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This paper compares the photocatalytic activities of Au/TiO2 (Au loadings 0-4 wt.%) and Ag/TiO2 photocatalysts (Ag loadings 0-4 wt.%) for H2 production from ethanol-water mixtures under UV irradiation. Au and Ag nanoparticles were deposited on commercially available Degussa P25 TiO2 (85% anatase, 15% rutile) using deposition-precipitation and liquid impregnation methods, respectively. TEM analyses showed the average noble metal nanoparticle size to be ~5 nm for the Au/TiO2 photocatalysts and ~3 nm for the Ag/TiO2 photocatalysts. Au/TiO2 photocatalysts showed a strong localised surface plasmon resonance (LSPR) at 570 nm characteristic for nanocrystalline Au. Complementary XRD studies confirmed that Au and Ag nanoparticles were present in metallic form. Photoluminescence measurements revealed that Au and Ag nanoparticles effectively suppress electron-hole recombination in TiO2, thereby enhancing the photocatalytic activity of TiO2 for hydrogen production. Au/TiO2 photocatalysts were far more active for H2 production from ethanol-water mixtures than Ag/TiO2 photocatalysts. A 1 wt.% Au/TiO2 photocatalyst yielded the highest H2 production rate (34 mmol g?1 h?1). Amongst the Ag/TiO2 photocatalysts, the 2 wt.% Ag/TiO2 sample was the most active (3.7 mmol g?1 h?1). Results are rationalised in terms of differences in the electronic properties of supported Au and Ag nanoparticles, with the former being near ideal for H2 production.
Vedran Jovic; Pei-Huan Hsieh; Wan-Ting Chen; Dongxiao Sun-Waterhouse; Tilo S├Čhnel; Geoffrey I.N. Waterhouse
Magnetic properties of epitaxial Co-doped anatase TiO2 thin films with excellent structural quality
The heteroepitaxy of Co-doped anatase TiO2 on LaAlO3(001) has been refined with the goal of determining the relationship between structural quality and magnetic ordering. By significantly reducing the deposition rate and substrate temperature, well-ordered Co:TiO2 films with unprecedented crystalline quality were obtained by oxygen-plasma-assisted molecular beam epitaxy, as characterized by x-ray diffraction. These films exhibit uniform Co doping, with no evidence of Co segregation or secondary phases throughout the film depth or on the surface. Despite the improvement in crystalline quality and Co distribution, the films exhibit negligible ferromagnetism, with saturation moments of only ~0.1 ?B/Co. This loss of ferromagnetism is in stark contrast to faster-grown Co:TiO2 films, where a higher growth rate and substrate temperature typically result in lower crystalline quality, a highly non-uniform Co distribution, and average saturation moments of ~1.2 ?B/Co. The presence of ferromagnetism in faster-grown Co:TiO2 does not appear to arise from intrinsic point defects present in the bulk material, such as charge-compensating oxygen vacancies, but is instead attributed to the presence of extended structural defects.
Kaspar, Tiffany C.; Droubay, Timothy C.; McCready, David E.; Nachimuthu, Ponnusamy; Heald, Steve M.; Wang, Chong M.; Lea, Alan S.; Shutthanandan, V.; Chambers, Scott A.; Toney, Michael F.
Effects of TiCl4 Purity on the Sinterability of Armstrong-Processed Ti Powder
A series of high purity and low purity powders were synthesized from TiCl4 by the Armstrong process. While both powders displayed swelling when consolidated and sintered, the lower purity powder exhibited this phenomenon in significantly lower degree. The improvement is attributed to the increase in the onset of sintering temperature, which mitigates the entrapment of volatile impurities that would otherwise lead to pore formation and growth. The net effect is that the use of a lower purity TiCl4 may beneficial in two ways: (1) it is a potentially lower cost precursor to Ti powder production and (2) the trace impurities allow higher density components to be fabricated via a typical low-cost press and sinter approach.
Weil, K. Scott; Hovanski, Yuri; Lavender, Curt A.
Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 35), Al6O5 , and Al7O5 clusters
Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 3┬Ł5), Al6O5 , and Al7O5 clusters Giovanni Meloni, Michael J. Ferguson and Daniel M. Neumark Department of Chemistry as an Advance Article on the web 9th September 2003 The Al3O2 , Al3O3 , Al4Ox , Al5Ox (x ┬╝ 3┬Ł5), Al6O5 , and Al7
Neumark, Daniel M.
Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2...
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Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Abstract: Understanding hydrogen formation on TiO2...
2013 ALS User Meeting Highlights
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2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights Print This year's ALS User Meeting launched with a welcome from Users' Executive Committee Chair Corie Ralston and LBNL Director Paul Alivisatos. ALS Director Roger Falcone followed with a "state of the ALS" presentation that began with a reminder of the ALS mission, which he noted remains true even in the midst of a government shutdown: "Supporting users in doing outstanding science in a safe environment." Falcone gave the 414 meeting attendees an update on the ALS beamlines, which included good news about increased user numbers thanks to the new RAPIDD access system, enhanced robotics, and remote capabilities. Falcone reflected that ALS metrics continue to represent our highly productive users-the number of journal articles and papers per user that come from ALS research have continued to grow in the past year. Looking forward, Falcone touched on how a proposed ALS upgrade to a diffraction-limited light source would increase scientific capabilities.
2013 ALS User Meeting Highlights
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2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights Print Thursday, 24 October 2013 09:06 This year's ALS User Meeting launched with a welcome from Users' Executive Committee Chair Corie Ralston and LBNL Director Paul Alivisatos. ALS Director Roger Falcone followed with a "state of the ALS" presentation that began with a reminder of the ALS mission, which he noted remains true even in the midst of a government shutdown: "Supporting users in doing outstanding science in a safe environment." Falcone gave the 414 meeting attendees an update on the ALS beamlines, which included good news about increased user numbers thanks to the new RAPIDD access system, enhanced robotics, and remote capabilities. Falcone reflected that ALS metrics continue to represent our highly productive users-the number of journal articles and papers per user that come from ALS research have continued to grow in the past year. Looking forward, Falcone touched on how a proposed ALS upgrade to a diffraction-limited light source would increase scientific capabilities.
GAMETOPHYTIC SELF-INCOMPATIBILITY (Newbigin et al., 1993; Matton et al., 1994; Dodds et al., 1997)
GAMETOPHYTIC SELF-INCOMPATIBILITY (Newbigin et al., 1993; Matton et al., 1994; Dodds et al., 1997, but expressed at high levels in the style. d. There are high levels of this gene product in self-incompatible species, whereas very low levels in self-compatible species. f. Generalized features: #12;Self-incompatibility
Bhattacharyya, Madan Kumar
A New Method of Low Cost Production of Ti Alloys to Reduce Energy...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
or otherwise restricted information. Project Objective Develop a novel low cost method for manufacturing Ti Demonstrate the mechanical properties of Ti using the...
Film Coating Process Research and Characterization of TiN Coated Racetrack-type Ceramic Pipe
TiN film was coated on the internal face of racetrack-type ceramic pipe by three different methods: radio-frequency sputtering, DC sputtering and DC magnetron sputtering. The deposition rates of TiN film under different coating methods were compared. According to the AFM, SEM, XPS test results,these properties were analyzed, such as TiN film roughness and surface morphology. At the same time, the deposition rates were studied under two types' cathode, Ti wires and Ti plate. According to the SEM test results, Ti plate cathode can improve the TiN/Ti film deposition rate obviously.
Wang, Jie; Zhang, Bo; Wei, Wei; Fan, Le; Pei, Xiangtao; Hong, Yuanzhi; Wang, Yong
Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions...
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Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions with Oxygen Vacancies. Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions with Oxygen Vacancies....
Erosion resistance of continuously reinforced SiC¢Ti-based metal matrix composites by a SiC/water slurry jet
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The erosion of a continuously reinforced SiC (Sigma 1140 plus)/Ti¢6Al¢4V composite was investigated with a SiC/water slurry jet at various angles on a plane perpendicular to the direction of the reinforcement. The results demonstrate the combination of both ceramic and metallic properties. Both the low-angle erosion resistance of ceramics as well as the high-angle resistance of a metallic alloy lead to an overall reduction in erosion rate at the various angles. Ti/SiC composite shows the best erosive wear resistance indicating that the combination effect between ductile Ti-based matrix and high strength SiC fibre for continuously fibre-reinforced Ti-based metal matrix composites (MMCs) plays a key role in increasing the erosive resistance. To gain a better understanding of the combination and synergistic enhancement of erosion resistance for two components in SiC/Ti composite materials, a shadowing effect and effect of reducing impact energy on SiC fibre during erosion are discussed. A simple theoretical model based on experimental data and a modified inverse rule-of-mixtures averaging law of erosion resistance for SiC fibre-reinforced \\{MMCs\\} are discussed.
Q Fang; P.S Sidky; G.M Hocking
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
ENVIRONMENT ENVIRONMENT AL REVI EW for CATEG ORI CAL EXCLUS ION DETE RMINATION Rocky Mo unta in Region, Weste rn A rea Power Administra tion Stru cture Replace ment Fla min g Go rge-Vern a l No.3 138-kV tra nsmiss ion lin e (Struct ure No. 25/6) Spr ing 201 2 A. Ilricf J)cscription of Proposal: Western Area Power Adm inistration (Western) proposes to replace Structure No. 25/6 on the Flaming Gorge-Vernal No.3 138-kV transmission line. The structure is located on Bureau of Land Management lands in Uintah County. Utah (Township 3S, Range 22E, Section 7; Donkey Flat 7.5' USGS quadrangle). Work consists of removal and in-kind replacement of the wood H-frame structure and anchors utilizing rubber tired vehicles. crane, bucket truck, pole trucks/trailers, auger rig. and pick-up trucks. All work will be conducted on Western's existing
Microstructure and mechanical properties of Ni sub 3 Al-based alloys reinforced with particulates
Hot-extrusion was used to produce Ni{sub 3}Al-based alloys to which 10 vol % TiN, NbC, HfO{sub 2}, or HfN was added for reinforcement. The TiN, NbC, and HfO{sub 2} particulates produced Ni{sub 3}Al-matrix composites in which no reaction was noted at the particle-matrix interface. However, the addition of HfN resulted in extensive reaction in which the hafnium appeared to diffuse into the matrix. Microstructures of this alloy showed a complex array of phases and voids where the HfN particles are presumed to have been originally. Hot hardness, compression, and compression creep tests were preformed on specimens cut from the extruded bar of each alloy. No significant strengthening was observed for the alloys containing TiN, NbC, or HfO{sub 2}. However the HfN-containing alloy did show significant strengthening in simple compression and compression creep. This presentation will include microstructures and the results of the mechanical properties tests. 26 refs., 5 figs.
McKamey, C.G.; Carmichael, C.A.
Electron energy loss study of TiC[111].
The electron energy loss (EEL) spectra of TiC (111) were measured over a wide range of electron primary energies. The electron energy losses below 16 eV were analyzed using the theoretical band calculations of Price and Cooper [11]. The volume and surface plasma excitations were identified from their electron primary energy dependence. Energy losses due to core electrons autoinization effects were identified above 35 eV. We observed a difference in the electronic structure of the surface vs. the bulk of TiC. The temperature dependence of the EEL spectra was studied between 300 to 1250 K. The reaction of the TiC surface with ethylene and oxygen was also investigated. The ethylene bonding to the TiC surface was found to be very weak. There is evidence of the formation of surface defects on the TiC (111) surface at high temperatures.
Chan, Y.; Lee, S. W.; Liao, D.; Cooper, B. R.; Montano, P. A.; Materials Science Division; Brooklyn Coll. of City Univ. of New York; West Virginia Univ.
Energieversorgung als DienstleistungŚElektrizitõtswirtschaft
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Im Herbst 1988 legte die VDEW ihren Hitgliedsunternehmen das Positionspapier ōDie Stromversorger als Dienstleistungspartnerö vor und machte es zugleich einer interessierten ųffentlichkeit bekannt. Das Position...
K. Bechthold
Energieversorgung als DienstleistungŚMineral÷lwirtschaft
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Meine Damen, meine Herren, Energieversorgung als Dienstleistung, dieses Thema beherrscht die Energiediskussion seit einiger Zeit. Der Begriff ist etwas schillernd, seine genaue Eingrenzung schwierig, aber er k...
P. Schillm÷ller
Transitrõume als Orte des Konsums.
??Insbesondere seit den 1990er Jahren ist international eine wachsende Bedeutung der Transitrõume Tankstelle, Flughafen und Bahnhof als Einzelhandels- und Dienstleistungsstandorte zu beobachten. Vielfõltige Gr³nde sowohlģ (more)
Korn, Juliane
Thermodynamics of the solid solution of hydrogen in ?-titanium alloys: ?-TiMo and ?-TiRe
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The solid solution of hydrogen has been investigated in a series of random ?-TiMo alloys ranging from 0¢65 atom % Mo via determination of pressure-composition-temperature relationships; additionally, one (?-TiRe alloy (Ti37 atom % Re) was investigated. The thermodynamic parameters of hydrogen solution were generated from the p-c-T data. The relative partial molar enthalpy at infinite dilution, ?H?Ho, exhibited by ?-TiMo alloys were adjusted to conditions of fixed volume, that of pure ?-Ti. It was found that variations in the resulting ?E?Ho correlated roughly with variations in the electron density of states at the Fermi level. The relative partial molar entropy at infinite dilution was found to vary linearly with Mo content and it is suggested that this trend reflects a blocking of potentially available interstitial sites to hydrogen occupation by Mo atoms at small hydrogen contents. Examination of the excess free energy vs hydrogen content relationships indicates that effects resulting from accommodation of hydrogen electrons by the metal conduction band are significant even at small hydrogen contents in the TiMo alloys; thus, explicit determination of the H-H interaction is not possible in the alloys. By contrast, electronic effects in pure ?-Ti are negligible at small HM and under fixed volume conditions, the H-H interactions in ?-Ti are attractive.
J.F. Lynch; J. Tanaka
CO Oxidation on Aun/TiO2 Catalysts Produced by Size-Selected Cluster Sungsik Lee, Chaoyang Fan, Tianpin Wu, and Scott L. Anderson*
. Indeed, Fu et al.2 recently showed that activity for the water gas shift reaction on Au/CeO2 and Pt/CeO2 TiO2 in an ultrahigh vacuum (UHV-base pressure 1 ├? 10-10 mbar). The kinetic energy spread of the Aun-8% of oxygen vacancies. (The XPS vacancy estimate was calibrated by a separate water dissociation experiment
Anderson, Scott L.
EPR study of Ti3+ ions formed under beta irradiation in silicate
1 EPR study of Ti3+ ions formed under beta irradiation in silicate glasses P. Lombard1* , N. Ollier in various silicate glasses have been studied by EPR spectroscopy at 20 K. Different parameters like the [Na of the Ti3+ ion EPR spectra in different Ti-doped silicate glasses has shown three different Ti3
Boyer, Edmond
DISCOVERY OF TWO DISTANT TYPE Ia SUPERNOVAE IN THE HUBBLE DEEP FIELDNORTH WITH THE ADVANCED CAMERA FOR SURVEYS
-standing indications from clus- ter and large-scale structure studies, and a mysterious dark energy component usually back- ground (CMB) analyses (e.g., Jaffe et al. 2001; Pryke et al. 2002), but the ratio of dark energy to matter at the present epoch is roughly 2 : 1. While a dark energy component is the favored explana- tion
Golimowski, David A.
Measurement of neutron capture on 50Ti at thermonuclear energies
At the Karlsruhe and Tuebingen 3.75 MV Van de Graaff accelerators the thermonuclear 50Ti(n,gamma)51Ti(5.8 min) cross section was measured by the fast cyclic activation technique via the 320.852 and 928.65 keV gamma-ray lines of the 51Ti-decay. Metallic Ti samples of natural isotopic composition and samples of TiO2 enriched in 50Ti by 67.53 % were irradiated between two gold foils which served as capture standards. The capture cross-section was measured at the neutron energies 25, 30, 52, and 145 keV, respectively. The direct capture cross section was determined to be 0.387 +/- 0.011 mbarn at 30 keV. We found evidence for a bound state s-wave resonance with an estimated radiative width of 0.34 eV which destructively interfers with direct capture. The strength of a suggested s-wave resonance at 146.8 keV was determined. The present data served to calculate, in addition to the directly measured Maxwellian averaged capture cross sections at 25 and 52 keV, an improved stellar 50Ti(n,gamma)51Ti rate in the thermonuclear energy region from 1 to 250 keV. The new stellar rate leads at low temperatures to much higher values than the previously recommended rate, e.g., at kT=8 keV the increase amounts to about 50 %. The new reaction rate therefore reduces the abundance of 50Ti due to s-processing in AGB stars.
P. V. Sedyshev; P. Mohr; H. Beer; H. Oberhummer; Yu. P. Popov; W. Rochow
Testing Models of Intrinsic Brightness Variations in Type Ia Supernovae, and their Impact on Measuring Cosmological Parameters
For spectroscopically confirmed type Ia supernovae we evaluate models of intrinsic brightness variations with detailed data/Monte-Carlo comparisons of the dispersion in the following quantities: Hubble-diagram scatter, color difference (B-V-c) between the true B-V color and the fitted color (c) from the SALT-II light curve model, and photometric redshift residual. The data sample includes 251 ugriz light curves from the 3-season Sloan Digital Sky Survey-II, and 191 griz light curves from the Supernova Legacy Survey 3-year data release. We find that the simplest model of a wavelength independent (coherent) scatter is not adequate, and that to describe the data the intrinsic scatter model must have wavelength-dependent variations. We use Monte Carlo simulations to examine the standard approach of adding a coherent scatter term in quadrature to the distance-modulus uncertainty in order to bring the reduced chi2 to unity when fitting a Hubble diagram. If the light curve fits include model uncertainties with the c...
Kessler, Richard; Marriner, John; Betoule, Marc; Brinkmann, Jon; Cinabro, David; El-Hage, Patrick; Frieman, Joshua; Jha, Saurabh; Mosher, Jennifer; Schneider, Donald P
Allegato "B" DOMANDA DI PARTECIPAZIONE AL CONCORSO DI AMMISSIONE AL
IN ROBOTICA, NEUROSCIENZE, NANOTECNOLOGIE E SCOPERTA FARMACI IN COLLABORAZIONE CON LA FONDAZIONE IIT Si prega'ammissione al Corso di Dottorato di Ricerca in Robotica, Neuroscienze, Nanotecnologie e Scoperta Farmaci
Sandini, Giulio
(12) United States Patent Harvey et al.
(12) United States Patent Harvey et al. (54) ANALYZING RETURN ON INVESTMENT OF ADVERTISING US 2009/0259518 Al Oct. 15,2009 Int. Cl. G06F 17/30 (2006.01) G07G 1/00 (2006.01) U.S. Cl et al. 911980 Block et al. 511982 Eskin et al. 1111982 Barber et al. 711985 Block et al. 111996
Shamos, Michael I.
Characterization and catalytic performance of vanadium supported on sulfated Ti-PILC catalysts issued from different Ti-precursors in selective catalytic reduction of nitrogen oxide by ammonia
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Vanadium supported on sulfated Ti-pillared clay catalysts (STi-PILCs) issued from different Ti-precursors were investigated for selective catalytic reduction (SCR) of NO by NH3 in the presence of O2. The STi-PILC...
J. Arfaoui; L. Khalfallah Boudali; A. Ghorbel; G. Delahay
AL PRO | Open Energy Information
AL PRO AL PRO Jump to: navigation, search Name AL-PRO Place Grossheide, Lower Saxony, Germany Zip 26532 Sector Wind energy Product AL-PRO is an inndependent expert office for wind forecasts, wind potential studies, turbulence inquiries, visualizations as well as sound and shade throw forecasts Coordinates 53.592743┬░, 7.34313┬░ Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":53.592743,"lon":7.34313,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning element formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.
John J. Cowan; James W. Truran
Nature of Transactions (TI) Code | National Nuclear Security Administration
National Nuclear Security Administration (NNSA)
Nature of Transactions (TI) Code | National Nuclear Security Administration Nature of Transactions (TI) Code | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Nature of Transactions (TI) Code Home > About Us > Our Programs > Nuclear Security > Nuclear Materials Management & Safeguards System > NMMSS Information, Reports & Forms > Code Tables > Nature of Transactions (TI) Code
Aluminium alloy based hydrogen storage tank operated with sodium aluminium hexahydride Na3AlH6
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Abstract Here we present the development of an aluminium alloy based hydrogen storage tank, charged with Ti-doped sodium aluminium hexahydride Na3AlH6. This hydride has a theoretical hydrogen storage capacity of 3Āmass-% and can be operated at lower pressure compared to sodium alanate NaAlH4. The tank was made of aluminium alloy EN AW 6082 T6. The heat transfer was realised through an oil flow in a bayonet heat exchanger, manufactured by extrusion moulding from aluminium alloy EN AW 6060 T6. Na3AlH6 is prepared from 4Āmol-% TiCl3 doped sodium aluminium tetrahydride NaAlH4 by addition of two moles of sodium hydride NaH in ball milling process. The hydrogen storage tank was filled with 213Āg of doped Na3AlH6 in dehydrogenated state. Maximum of 3.6Āg (1.7Āmass-% of the hydride mass) of hydrogen was released from the hydride at approximately 450ĀK and the same hydrogen mass was consumed at 2.5ĀMPa hydrogenation pressure. 45 cycle tests (rehydrogenation and dehydrogenation) were carried out without any failure of the tank or its components. Operation of the tank under real conditions indicated the possibility for applications with stationary HT-PEM fuel cell systems.
R. Urbanczyk; K. Peinecke; M. Felderhoff; K. Hauschild; W. Kersten; S. Peil; D. Bathen
E-Print Network 3.0 - al suolo al Sample Search Results
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DEI CAMBIAMENTI Summary: tradizionali rimboschimenti vincoli al dissodamento aumento delle provvigioni e dei turni riduzione degli... Commissione al Consiglio e al...
$Nb_{3}Al$ prototype conductor for the transmission line magnet
The Very Large Hadron Collider (VLHC), under consideration for construction at Fermilab in the next 1-2 decades, is a 100 TeV cm pp collider. A major cost driver is the magnet. R&D is underway on several possible magnet designs. A low-field (2T) superferric magnet, sometimes called a transmission line magnet, may be the most cost- effective route to the VLHC. Although NbTi is now the cheapest superconductor measured in cost/kA-meter, Nb/sub 3/Al has the potential advantage that it remains superconducting at higher temperature. It may be particularly suited to the single "turn" and long straight lengths of the transmission line design. The combination of the simple magnet design and the higher strain tolerance than e.g. Nb/sub 3/Sn allows a simple process of cable fabrication, reaction, and magnet assembly. This higher strain tolerance is an advantage for splicing in the field. Sumitomo Electric Industries is producing an Nb/sub 3/Al conductor for the Fermilab low-field magnet program. (9 refs).
Barzi, E; Malamud, E; Mazur, P O; Piekarz, H; Wake, M; Hayashi, K; Koganeya, M
Superhydrophilic TiO2 surface without photocatalytic activation
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Superhydrophilic TiO2 surface without photocatalytic activation Superhydrophilic TiO2 surface without photocatalytic activation Title Superhydrophilic TiO2 surface without photocatalytic activation Publication Type Journal Article Year of Publication 2010 Authors Zormpa, Vasileia, Xiaobo Chen, and Samuel S. Mao Journal Applied Physics Letter Volume 96 Issue 9 Date Published 12/2009 Abstract Since the discovery of extreme surface wetting phenomenon induced by ultraviolet photocatalysis, TiO2 has become the material of choice for environmental friendly applications such as self-cleaning coatings. Nevertheless, it remains a significant challenge to realize surfaces exhibiting persistent superhydrophilicity but without the need of external stimuli. We report a bioinspired TiO2 nanostructure that shows extreme superhydrophilicity without the need of light activation, and with stability against successive wetting-dewetting cycles. This ultimate TiO2 wetting surface exhibits high transmittance from near ultraviolet to the infrared, thus enabling practical antifogging technologies where transparency is critical.
Weldability and toughness assessment of Ti-microalloyed offshore steel
The present study has been carried out to investigate the coarse-grained heat-affected zone (CGHAZ) microstructure and crack tip opening displacement (CTOD) toughness of grade StE 355 Ti-microalloyed offshore steels. Three parent plates (40-mm thick) were studied, two of which had Ti microalloying with either Nb + V or Nb also present. As a third steel, conventional StE 355 steel without Ti addition was welded for comparison purposes. Multipass tandem submerged arc weld (SAW) and manual metal arc weld (SMAW) welds were produced. Different heat-affected zone (HAZ) microstructures were simulated to ascertain the detrimental effect of welding on toughness. All HAZ microstructures were examined using optical and electron microscopy. It can be concluded that Ti addition with appropriate steel processing, which disperses fine TiN precipitates uniformly, with a fine balance of other microalloying elements and with a Ti/N weight ratio of about 2.2, is beneficial for HAZ properties of StE 355 grade steel.
Rak, I.; Gliha, V. [Univ. of Maribor (Slovenia). Faculty of Mechanical Engineering; Kocak, M. [GKSS Research Center Geesthacht (Germany)
Shape memory behavior of ultrafine grained NiTi and TiNiPd shape memory alloys
The cyclic instability in shape memory characteristics of NiTi-based shape memory alloys (SMAs), such as transformation temperatures, transformation and irrecoverable strains and transformation hysteresis upon thermal and mechanical cycling limits...
Kockar, Benat
Deposition of TiN and HfO{sub 2} in a commercial 200 mm remote plasma atomic layer deposition reactor
The authors describe a remote plasma atomic layer deposition reactor (Oxford Instruments FlexAL trade mark sign ) that includes an inductively coupled plasma source and a load lock capable of handling substrates up to 200 mm in diameter. The deposition of titanium nitride (TiN) and hafnium oxide (HfO{sub 2}) is described for the combination of the metal-halide precursor TiCl{sub 4} and H{sub 2}-N{sub 2} plasma and the combination of the metallorganic precursor Hf[N(CH{sub 3})(C{sub 2}H{sub 5})]{sub 4} and O{sub 2} plasma, respectively. The influence of the plasma exposure time and substrate temperature has been studied and compositional, structural, and electrical properties are reported. TiN films with a low Cl impurity content were obtained at 350 deg. C at a growth rate of 0.35 A /cycle with an electrical resistivity as low as 150 {mu}{omega} cm. Carbon-free (detection limit <2 at. %) HfO{sub 2} films were obtained at a growth rate of 1.0 A /cycle at 290 deg. C. The thickness and resisitivity nonuniformity was <5% for the TiN and the thickness uniformality was <2% for the HfO{sub 2} films as determined over 200 mm wafers.
Heil, S. B. S.; Hemmen, J. L. van; Hodson, C. J.; Singh, N.; Klootwijk, J. H.; Roozeboom, F.; Sanden, M. C. M. van de; Kessels, W. M. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Oxford Instruments Plasma Technology, North End, Yatton BS49 4AP (United Kingdom); Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); NXP Semiconductors Research, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
Visible-Light Responsive Photocatalytic Fuel Cell Based on Ag/TiO2-NTs Photoanode and Cu2O/TiO2 Photocathode for Simultaneous Wastewater Treatment and Electricity Generation
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A visible-light driven photocatalytic fuel cell (PFC) system comprised of Ag/TiO2-NTs photoanode and Cu2O/TiO2/Ti photocathode was established for providing a self-sustained and...
Liao, Wenjuan
Plasma-sprayed CaTiSiO5 ceramic coating on Ti-6Al-4V with excellent bonding strength, stability and cellular bioactivity
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...doi:10.1016/j.biomaterials.2004.09.019 . Wu, C , J Chang, S Ni, and J Wang2006 In vitro bioactivity of akermanite ceramics. J. Biomed. Mater. Res. A. 76, 73-80. Wu, C , J Chang, W Zhai, and S NiA novel bioactive porous bredigite...
Microsoft Word - AL2005-01.doc
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Acquisition Letters (AL) that remain in effect are identified below. All other previously issued ALs have been superseded by a formal rule-making, incorporated into other...
Llanto al pie del Monte Carmelo
llantos feroces, llorando al pie de aquella fuente te estoySpring, 1988) Monte Carmelo al pie del Hay tiempo que no por
Ferrer, Juan Josķ Prat