Sample records for high entropy alloy

  1. Progress in High-Entropy Alloys

    SciTech Connect (OSTI)

    Gao, Michael C.

    2013-12-01T23:59:59.000Z

    Strictly speaking, high-entropy alloys (HEAs) refer to single-phase, solid-solution alloys with multiprincipal elements in an equal or a near-equal molar ratio whose configurational entropy is tremendously high. This special topic was organized to reflect the focus and diversity of HEA research topics in the community.

  2. Elevated-Temperature Corrosion of CoCrCuFeNiAl0.5Bx High-Entropy Alloys in Simulated Syngas Containing H2S

    SciTech Connect (OSTI)

    Dogan, Omer N.; Nielsen, Benjamin C.; Hawk, Jeffrey A.

    2013-08-01T23:59:59.000Z

    High-entropy alloys are formed by synthesizing five or more principal elements in equimolar or near equimolar concentrations. Microstructure of the CoCrCuFeNiAl{sub 0.5}B{sub x} (x = 0, 0.2, 0.6, 1) high-entropy alloys under investigation is composed of a mixture of disordered bcc and fcc phases and borides. These alloys were tested gravimetrically for their corrosion resistance in simulated syngas containing 0, 0.01, 0.1, and 1 % H{sub 2}S at 500 °C. The exposed coupons were characterized using XRD and SEM. No significant corrosion was detected at 500 °C in syngas containing 0 and 0.01 % H{sub 2}S while significant corrosion was observed in syngas containing 0.1 and 1 % H{sub 2}S. Cu{sub 1.96}S was the primary sulfide in the external corrosion scale on the low-boron high-entropy alloys, whereas FeCo{sub 4}Ni{sub 4}S{sub 8} on the high-boron high-entropy alloys. Multi-phase Cu-rich regions in the low-B high-entropy alloys were vulnerable to corrosive attack.

  3. Rapid precipitation in an Al0.5CrFeCoNiCu high entropy alloy

    E-Print Network [OSTI]

    Jones, N. G.; Christofidou, K. A.; Stone, H. J.

    2015-02-03T23:59:59.000Z

    that the intragranular precipitates observed within the interdendritic regions are ?, since this phase has a highly complex structure and is more commonly observed to form along grain boundaries 24-26. In addition, previous studies of duplex stainless steels have... ', Progress In Materials Science, 1972, 15(2), 79-+. 27. T. H. Chen and J. R. Yang: 'Effects of solution treatment and continuous cooling on sigma- phase precipitation in a 2205 duplex stainless steel', Materials Science and Engineering: A, 2001, 311...

  4. High strength alloys

    DOE Patents [OSTI]

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31T23:59:59.000Z

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  5. High strength alloys

    DOE Patents [OSTI]

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05T23:59:59.000Z

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  6. Conductivity and entanglement entropy of high dimensional holographic superconductors

    E-Print Network [OSTI]

    Romero-Bermúdez, Aurelio

    2015-01-01T23:59:59.000Z

    We investigate the dependence of the conductivity and the entanglement entropy on the space-time dimensionality $d$ in two holographic superconductors: one dual to a quantum critical point with spontaneous symmetry breaking, and the other modeled by a charged scalar that condenses at a sufficiently low temperature in the presence of a Maxwell field. In both cases the gravity background is asymptotically Anti de Sitter (AdS). In the large $d$ limit we obtain explicit analytical results for the conductivity at zero temperature and the entanglement entropy by a $1/d$ expansion. We show that the entanglement entropy is always smaller in the broken phase and identify a novel decay of the conductivity for intermediate frequencies. As dimensionality increases, the entanglement entropy decreases, the coherence peak in the conductivity becomes narrower and the ratio between the energy gap and the critical temperature decreases. These results suggest that the condensate interactions become weaker in high spatial dimens...

  7. ITP Metal Casting: Corrosion Testing Practices - High Alloy Corrosion...

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

    Metal Casting: Corrosion Testing Practices - High Alloy Corrosion Program ITP Metal Casting: Corrosion Testing Practices - High Alloy Corrosion Program lehighfs.pdf More Documents...

  8. "Exploring damage management of high performance metallic alloys in critical

    E-Print Network [OSTI]

    Acton, Scott

    Fatigue Localized corrosion degrades fatigue performance of high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys"Exploring damage management of high performance metallic alloys in critical systems to develop new

  9. Enhanced residual entropy in high-density nanoconfined bilayer ice

    E-Print Network [OSTI]

    Fabiano Corsetti; Jon Zubeltzu; Emilio Artacho

    2015-06-15T23:59:59.000Z

    A novel kind of crystal order in high-density nanoconfined bilayer ice is proposed from molecular dynamics and density-functional theory simulations. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with AA stacking. Uniquely amongst the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a residual entropy twice that of bulk ice.

  10. Ductile aluminide alloys for high temperature applications

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN); Koch, Carl C. (Oak Ridge, TN)

    1987-01-01T23:59:59.000Z

    Alloys are described which contain nickel, aluminum, boron, iron and in some instances manganese, niobium and titanium.

  11. High strength uranium-tungsten alloys

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Sheinberg, Haskell (Los Alamos, NM); Hogan, Billy M. (Los Alamos, NM); Lewis, Homer D. (Bayfield, CO); Dickinson, James M. (Los Alamos, NM)

    1991-01-01T23:59:59.000Z

    Alloys of uranium and tungsten and a method for making the alloys. The amount of tungsten present in the alloys is from about 4 wt % to about 35 wt %. Tungsten particles are dispersed throughout the uranium and a small amount of tungsten is dissolved in the uranium.

  12. High strength uranium-tungsten alloy process

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Sheinberg, Haskell (Los Alamos, NM); Hogan, Billy M. (Los Alamos, NM); Lewis, Homer D. (Bayfield, CO); Dickinson, James M. (Los Alamos, NM)

    1990-01-01T23:59:59.000Z

    Alloys of uranium and tungsten and a method for making the alloys. The amount of tungsten present in the alloys is from about 4 wt % to about 35 wt %. Tungsten particles are dispersed throughout the uranium and a small amount of tungsten is dissolved in the uranium.

  13. High Temperature Mechanical Properties of Molybdenum Solid Solution Alloys

    SciTech Connect (OSTI)

    Charit, I.; Murty, K.L. [College of Engineering, North Carolina State University, Raleigh, NC 27695, (United States)

    2006-07-01T23:59:59.000Z

    Demanding material requirements for space nuclear power systems have called for the use of refractory alloys. Molybdenum alloys are such candidate materials because of their good mechanical properties at fairly high temperatures, low neutron capture cross-section, and superior resistance to the attack of liquid metals. However, conventional Mo alloys have low ductility at lower temperatures. Hence, there have been several attempts to improve their viability. One of those approaches has been to alloy Mo with various alloying additions in solid solution, most notably with rhenium (Re). In this study the high temperature deformation behavior of various Mo-X (X Re, W, Nb, Hf) alloys is reviewed. High temperature deformation data for these solid solution alloys are analyzed in the light of existing deformation theories. Alloys with both Class-M and -A type behavior are identified and thus, various mechanisms are found to operate. Sometimes data interpretation becomes difficult due to the presence of second phase particles. Results are compared with unalloyed Mo to bring out the importance of solid solution alloying. (authors)

  14. Ductile aluminide alloys for high temperature applications

    DOE Patents [OSTI]

    Liu, C.T.; Kock, C.C.

    1983-08-03T23:59:59.000Z

    Heat- and corrosion-resistant alloys are described which contain nickel, aluminum, boron, iron and in some instances manganese, niobium and titanium.

  15. Ductile aluminide alloys for high temperature applications

    DOE Patents [OSTI]

    Liu, C.T.; Stiegler, J.O.

    1983-12-21T23:59:59.000Z

    Improved Ni/sub 3/Al alloys are provided by inclusion of boron, hafnium or zirconium, and in some species, iron.

  16. Crevice corrosion repassivation temperatures of highly alloyed stainless steels

    SciTech Connect (OSTI)

    Valen, S.; Gartland, P.O. [SINTEF Corrosion Center, Trondheim (Norway)

    1995-10-01T23:59:59.000Z

    An investigation was conducted to study the repassivation temperature of a highly alloyed austenitic (UNS S31254) and of a highly alloyed duplex (UNS S32750) stainless steel (SS). When initiated at a high temperature, repassivation occurred at a temperature level significantly lower than normally associated with initiation of crevice corrosion. Experimental results combined with computer modeling of crevice corrosion explored the mechanistic aspects. In this respect, the similarity between the hysteresis observed by cyclic polarization and cyclic temperature tests was emphasized.

  17. Towards electroformed nanostructured aluminum alloys with high strength and ductility

    E-Print Network [OSTI]

    Ruan, Shiyun

    Nanostructured Al–Mn alloys are proposed as high-strength low-density materials, which can be electroformed (i.e., produced electrolytically and removed from the substrate) from ionic liquid. A variety of current waveforms, ...

  18. Lyapunov exponents and Kolmogorov-Sinai entropy for a high-dimensional convex billiard

    SciTech Connect (OSTI)

    Papenbrock, Thomas [Institute for Nuclear Theory, Department of Physics, University of Washington, Seattle, Washington 98195 (United States)] [Institute for Nuclear Theory, Department of Physics, University of Washington, Seattle, Washington 98195 (United States)

    2000-02-01T23:59:59.000Z

    We compute the Lyapunov exponents and the Kolmogorov-Sinai (KS) entropy for a self-bound N-body system that is realized as a convex billiard. This system exhibits truly high-dimensional chaos, and 2N-4 Lyapunov exponents are found to be positive. The KS entropy increases linearly with the numbers of particles. We examine the chaos generating defocusing mechanism and investigate how high-dimensional chaos develops in this system with no dispersing elements. (c) 2000 The American Physical Society.

  19. Iron aluminide alloys with improved properties for high temperature applications

    DOE Patents [OSTI]

    McKamey, Claudette G. (Knoxville, TN); Liu, Chain T. (Oak Ridge, TN)

    1990-01-01T23:59:59.000Z

    An improved iron aluminide alloy of the DO.sub.3 type that has increased room temperature ductility and improved high elevated temperature strength. The alloy system further is resistant to corrosive attack in the environments of advanced energy corrosion systems such as those using fossil fuels. The resultant alloy is relatively inexpensive as contrasted to nickel based and high nickel steels currently utilized for structural components. The alloy system consists essentially of 26-30 at. % aluminum, 0.5-10 at. % chromium, 0.02-0.3 at. % boron plus carbon, up to 2 at. % molybdenum, up to 1 at. % niobium, up to 0.5 at. % zirconium, up to 0.1 at. % yttrium, up to 0.5 at. % vanadium and the balance iron.

  20. Iron aluminide alloys with improved properties for high temperature applications

    DOE Patents [OSTI]

    McKamey, C.G.; Liu, C.T.

    1990-10-09T23:59:59.000Z

    An improved iron aluminide alloy of the DO[sub 3] type is described that has increased room temperature ductility and improved high elevated temperature strength. The alloy system further is resistant to corrosive attack in the environments of advanced energy conversion systems such as those using fossil fuels. The resultant alloy is relatively inexpensive as contrasted to nickel based and high nickel steels currently utilized for structural components. The alloy system consists essentially of 26--30 at. % aluminum, 0.5--10 at. % chromium, 0.02--0.3 at. % boron plus carbon, up to 2 at. % molybdenum, up to 1 at. % niobium, up to 0.5 at. % zirconium, up to 0.1 at. % yttrium, up to 0.5 at. % vanadium and the balance iron. 3 figs.

  1. Improved high temperature creep resistant austenitic alloy

    DOE Patents [OSTI]

    Maziasz, P.J.; Swindeman, R.W.; Goodwin, G.M.

    1988-05-13T23:59:59.000Z

    An improved austenitic alloy having in wt% 19-21 Cr, 30-35 Ni, 1.5-2.5 Mn, 2-3 Mo, 0.1-0.4 Si, 0.3-0.5 Ti, 0.1-0.3 Nb, 0.1-0.5 V, 0.001-0.005 P, 0.08-0.12 C, 0.01-0.03 N, 0.005-0.01 B and the balance iron that is further improved by annealing for up to 1 hour at 1150-1200/degree/C and then cold deforming 5-15%. The alloy exhibits dramatically improved creep rupture resistance and ductility at 700/degree/C. 2 figs.

  2. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    SciTech Connect (OSTI)

    Coulter, K

    2013-09-30T23:59:59.000Z

    At the beginning of this project, thin film amorphous alloy membranes were considered a nascent but promising new technology for industrial-scale hydrogen gas separations from coal- derived syngas. This project used a combination of theoretical modeling, advanced physical vapor deposition fabricating, and laboratory and gasifier testing to develop amorphous alloy membranes that had the potential to meet Department of Energy (DOE) targets in the testing strategies outlined in the NETL Membrane Test Protocol. The project is complete with Southwest Research Institute® (SwRI®), Georgia Institute of Technology (GT), and Western Research Institute (WRI) having all operated independently and concurrently. GT studied the hydrogen transport properties of several amorphous alloys and found that ZrCu and ZrCuTi were the most promising candidates. GT also evaluated the hydrogen transport properties of V, Nb and Ta membranes coated with different transition-metal carbides (TMCs) (TM = Ti, Hf, Zr) catalytic layers by employing first-principles calculations together with statistical mechanics methods and determined that TiC was the most promising material to provide catalytic hydrogen dissociation. SwRI developed magnetron coating techniques to deposit a range of amorphous alloys onto both porous discs and tubular substrates. Unfortunately none of the amorphous alloys could be deposited without pinhole defects that undermined the selectivity of the membranes. WRI tested the thermal properties of the ZrCu and ZrNi alloys and found that under reducing environments the upper temperature limit of operation without recrystallization is ~250 °C. There were four publications generated from this project with two additional manuscripts in progress and six presentations were made at national and international technical conferences. The combination of the pinhole defects and the lack of high temperature stability make the theoretically identified most promising candidate amorphous alloys unsuitable for application as hydrogen separation membranes in coal fire systems.

  3. Computational and Experimental Development of Novel High Temperature Alloys

    SciTech Connect (OSTI)

    Kramer, M.J.; Ray, P.K.; and Akinc, M.

    2010-06-29T23:59:59.000Z

    The work done in this paper is based on our earlier work on developing an extended Miedema model and then using it to downselect potential alloy systems. Our approach is to closely couple the semi-empirical methodologies to more accurate ab initio methods to dentify the best candidates for ternary alloying additions. The architectural framework for our material's design is a refractory base metal with a high temperature intermetallic which provides both high temperature creep strength and a source of oxidatively stable elements. Potential refractory base metals are groups IIIA, IVA and VA. For Fossil applications, Ni-Al appears to be the best choice to provide the source of oxidatively stable elements but this system requires a 'boost' in melting temperatures to be a viable candidate in the ultra-high temperature regime (> 1200C). Some late transition metals and noble elements are known to increase the melting temperature of Ni-Al phases. Such an approach suggested that a Mo-Ni-Al system would be a good base alloy system that could be further improved upon by dding Platinum group metals (PGMs). In this paper, we demonstrate the variety of microstructures that can be synthesized for the base alloy system, its oxidation behavior as well as the oxidation behavior of the PGM substituted oxidation resistant B2 NiAl phase.

  4. Neural network analysis of strength and ductility of welding alloys for high strength low

    E-Print Network [OSTI]

    Cambridge, University of

    Neural network analysis of strength and ductility of welding alloys for high strength low alloy There are considerable demands for the development of weld metals for high strength low alloy steels. To assist in meeting such demands, a neural network was trained and tested on a set of data obtained on weld metals

  5. Feeding of High-Nickel Alloy Castings KENT D. CARLSON, SHOUZHU OU, and CHRISTOPH BECKERMANN

    E-Print Network [OSTI]

    Beckermann, Christoph

    Feeding of High-Nickel Alloy Castings KENT D. CARLSON, SHOUZHU OU, and CHRISTOPH BECKERMANN Feeding of the nickel-based alloys CZ-100, M-35-1, and CW-12MW, as well as of the austenitic stainless steel CN-7M are shown to provide accurate FDs for the casting trial plates. The FDs of the high-nickel alloys (except CZ

  6. Quantifying the economic and commercial potential of a high strength, low thermal coefficient super-alloy

    E-Print Network [OSTI]

    Liew, Heng Lee Henry

    2008-01-01T23:59:59.000Z

    Inspired by the importance of having a favourable sheathing material for superconducting wires, a high-strength, low thermal coefficient (CTE) super-alloy has been developed. Known as Incoloy 908, this super-alloy's material ...

  7. High-strain-rate nanoindentation behavior of fine-grained magnesium alloys

    E-Print Network [OSTI]

    Somekawa, Hidetoshi

    The effects of temperature and alloying elements on deformation in the high-strain-rate regime were investigated by testing fine-grained magnesium alloys with an average grain size of 2 ? 3 ?m by a nanoindentation technique. ...

  8. DEVELOPMENT OF A HIGH STRENGTH, HYDROGEN-RESISTANT AUSTENITIC ALLOY

    E-Print Network [OSTI]

    Chang, K.M.

    2010-01-01T23:59:59.000Z

    mechanical properties to gaseous hydrogen was determinedof these properties the alloy was subjected to hydrogenTensile Properties of Alloy E in Air and in Hydrogen.

  9. Highly Dispersed Alloy Catalyst for Durability

    SciTech Connect (OSTI)

    Vivek S. Murthi (Primary Contact), Elise Izzo, Wu Bi, Sandra Guerrero and Lesia Protsailo

    2013-01-08T23:59:59.000Z

    Achieving DOE�¢����s stated 5000-hr durability goal for light-duty vehicles by 2015 will require MEAs with characteristics that are beyond the current state of the art. Significant effort was placed on developing advanced durable cathode catalysts to arrive at the best possible electrode for high performance and durability, as well as developing manufacturing processes that yield significant cost benefit. Accordingly, the overall goal of this project was to develop and construct advanced MEAs that will improve performance and durability while reducing the cost of PEMFC stacks. The project, led by UTC Power, focused on developing new catalysts/supports and integrating them with existing materials (membranes and gas diffusion layers (GDLs)) using state-of-the-art fabrication methods capable of meeting the durability requirements essential for automotive applications. Specifically, the project work aimed to lower platinum group metals (PGM) loading while increasing performance and durability. Appropriate catalysts and MEA configuration were down-selected that protects the membrane, and the layers were tailored to optimize the movements of reactants and product water through the cell to maximize performance while maintaining durability.

  10. Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications

    SciTech Connect (OSTI)

    Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar

    2002-11-24T23:59:59.000Z

    To serve as an interconnect / gas separator in an SOFC stack, an alloy should demonstrate the ability to provide (i) bulk and surface stability against oxidation and corrosion during prolonged exposure to the fuel cell environment, (ii) thermal expansion compatibility with the other stack components, (iii) chemical compatibility with adjacent stack components, (iv) high electrical conductivity of the surface reaction products, (v) mechanical reliability and durability at cell exposure conditions, (vii) good manufacturability, processability and fabricability, and (viii) cost effectiveness. As the first step of this approach, a composition and property database was compiled for high temperature alloys in order to assist in determining which alloys offer the most promise for SOFC interconnect applications in terms of oxidation and corrosion resistance. The high temperature alloys of interest included Ni-, Fe-, Co-base superal

  11. Nucleosynthesis in Fast Expansions of High-Entropy, Proton Rich Matter

    E-Print Network [OSTI]

    G. C. Jordan IV; B. S. Meyer

    2004-06-29T23:59:59.000Z

    We demonstrate that nucleosynthesis in rapid, high-entropy expansions of proton-rich matter from high temperature and density can result in a wider variety of abundance patterns than heretofore appreciated. In particular, such expansions can produce iron-group nuclides, p-process nuclei, or even heavy, neutron-rich isotopes. Such diversity arises because the nucleosynthesis enters a little explored regime in which the free nucleons are not in equilibrium with the abundant alpha particles. This allows nuclei significantly heavier than iron to form in t he presence of abundant free nucleons early in the expansion. As the temperature drops, nucleons increasingly assemble into alpha particles and heavier nuclei. If the assembly is efficient, the resulting depletion of free neutrons allows disintegrat ion flows to drive nuclei back down to iron and nickel. If this assembly is inefficient, then the large abundance of free nucleons prevents the disintegration flows and leaves a distribution of heavy nuclei after reaction freezeout. For cases in between, an intermediate abundance distribution, enriched in p-process isotopes, is frozen out. These last expansions may contribute to the solar system's supply of the p-process nuclides if mildly proton-rich, high-entropy matter is ejected from proto-neutron stars winds or other astrophysical sites. Also sign ificant is the fact that, because the nucleosynthesis is primary, the signature of this nucleosyn thesis may be evident in metal poor stars.

  12. Band anticrossing effects in highly mismatched semiconductor alloys

    SciTech Connect (OSTI)

    Wu, Junqiao

    2002-09-09T23:59:59.000Z

    The first five chapters of this thesis focus on studies of band anticrossing (BAC) effects in highly electronegativity- mismatched semiconductor alloys. The concept of bandgap bowing has been used to describe the deviation of the alloy bandgap from a linear interpolation. Bowing parameters as large as 2.5 eV (for ZnSTe) and close to zero (for AlGaAs and ZnSSe) have been observed experimentally. Recent advances in thin film deposition techniques have allowed the growth of semiconductor alloys composed of significantly different constituents with ever- improving crystalline quality (e.g., GaAs{sub 1-x}N{sub x} and GaP{sub 1-x}N{sub x} with x {approx}< 0.05). These alloys exhibit many novel and interesting properties including, in particular, a giant bandgap bowing (bowing parameters > 14 eV). A band anticrossing model has been developed to explain these properties. The model shows that the predominant bowing mechanism in these systems is driven by the anticrossing interaction between the localized level associated with the minority component and the band states of the host. In this thesis I discuss my studies of the BAC effects in these highly mismatched semiconductors. It will be shown that the results of the physically intuitive BAC model can be derived from the Hamiltonian of the many-impurity Anderson model. The band restructuring caused by the BAC interaction is responsible for a series of experimental observations such as a large bandgap reduction, an enhancement of the electron effective mass, and a decrease in the pressure coefficient of the fundamental gap energy. Results of further experimental investigations of the optical properties of quantum wells based on these materials will be also presented. It will be shown that the BAC interaction occurs not only between localized states and conduction band states at the Brillouin zone center, but also exists over all of k-space. Finally, taking ZnSTe and ZnSeTe as examples, I show that BAC also occurs between localized states and the valence band states. Soft x-ray fluorescence experiments provide direct evidence of the BAC interaction in these systems. In the final chapter of the thesis, I describe and summarize my studies of optical properties of wurtzite InN and related alloys. Early studies performed on InN films grown by sputtering techniques suggested a direct bandgap of {approx}1.9 eV for this semiconductor. Very recently, high-quality InN films with much higher mobility have become available by using the molecular beam epitaxy growth method. Optical experiments carried out on these samples reveal a narrow bandgap for InN of 0.77 eV, much lower than the previously accepted value. Optical properties of InGaN and InAlN ternaries on the In rich side have also been characterized and are found to be consistent with the narrow bandgap of InN. The bandgap bowing parameters in these alloys were determined. In the context of these findings, the bandgap energies of InGaN and InAlN were found to cover a wide spectral range from the infrared for InN to the ultraviolet for GaN and deep ultraviolet for AlN. The significance of this work is rooted in many important applications of nitride semiconductors in optoelectronics and solar energy conversion devices.

  13. OXIDATION MECHANISMS OF LOW ENERGY-HIGH FLUX NITRIDED ODS FeAl INTERMETALLIC ALLOY

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    OXIDATION MECHANISMS OF LOW ENERGY-HIGH FLUX NITRIDED ODS FeAl INTERMETALLIC ALLOY F. Pedraza*, J)5.46.45.72.72 Abstract Microscopy studies of low energy-high flux nitrided ODS FeAl Grade 3 intermetallic alloy reveal nitridation treatment at moderate temperature of ODS FeAl Grade 3 has been performed to modify the surface

  14. Composite Sequence Compaction for Finite-State Machines Using Block Entropy and High-Order Markov Models*

    E-Print Network [OSTI]

    Pedram, Massoud

    Composite Sequence Compaction for Finite-State Machines Using Block Entropy and High-Order Markov an effective technique for accurate modeling of the external input sequences that affect the behavior of Finite propose an effective approach to compact an initial sequence into a much shorter, equivalent one

  15. High strength and density tungsten-uranium alloys

    DOE Patents [OSTI]

    Sheinberg, Haskell (Los Alamos, NM)

    1993-01-01T23:59:59.000Z

    Alloys of tungsten and uranium and a method for making the alloys. The amount of tungsten present in the alloys is from about 55 vol % to about 85 vol %. A porous preform is made by sintering consolidated tungsten powder. The preform is impregnated with molten uranium such that (1) uranium fills the pores of the preform to form uranium in a tungsten matrix or (2) uranium dissolves portions of the preform to form a continuous uranium phase containing tungsten particles.

  16. Copper modified austenitic stainless steel alloys with improved high temperature creep resistance

    DOE Patents [OSTI]

    Swindeman, R.W.; Maziasz, P.J.

    1987-04-28T23:59:59.000Z

    An improved austenitic stainless steel that incorporates copper into a base Fe-Ni-Cr alloy having minor alloying substituents of Mo, Mn, Si, T, Nb, V, C, N, P, B which exhibits significant improvement in high temperature creep resistance over previous steels. 3 figs.

  17. Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase ? and ? phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

  18. Materials corrosion of high temperature alloys immersed in 600C binary nitrate salt.

    SciTech Connect (OSTI)

    Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth

    2013-03-01T23:59:59.000Z

    Thirteen high temperature alloys were immersion tested in a 60/40 binary nitrate salt. Samples were interval tested up to 3000 hours at 600%C2%B0C with air as the ullage gas. Chemical analysis of the molten salt indicated lower nitrite concentrations present in the salt, as predicted by the equilibrium equation. Corrosion rates were generally low for all alloys. Corrosion products were identified using x-ray diffraction and electron microprobe analysis. Fe-Cr based alloys tended to form mixtures of sodium and iron oxides, while Fe-Ni/Cr alloys had similar corrosion products plus oxides of nickel and chromium. Nickel based alloys primarily formed NiO, with chromium oxides near the oxide/base alloy interface. In625 exhibited similar corrosion performance in relation to previous tests, lending confidence in comparisons between past and present experiments. HA230 exhibited internal oxidation that consisted of a nickel/chromium oxide. Alloys with significant aluminum alloying tended to exhibit superior performance, due formation of a thin alumina layer. Soluble corrosion products of chromium, molybdenum, and tungsten were also formed and are thought to be a significant factor in alloy performance.

  19. Two-phase chromium-niobium alloys exhibiting improved mechanical properties at high temperatures

    DOE Patents [OSTI]

    Liu, C.T.; Takeyama, Masao.

    1994-02-01T23:59:59.000Z

    The specification discloses chromium-niobium alloys which exhibit improved mechanical properties at high temperatures in the range of 1250 C and improved room temperature ductility. The alloys contain a Cr[sub 2]Nb-rich intermetallic phase and a Cr-rich phase with an overall niobium concentration in the range of from about 5 to about 18 at. %. The high temperature strength is substantially greater than that of state of the art nickel-based superalloys for enhanced high temperature service. Further improvements in the properties of the compositions are obtained by alloying with rhenium and aluminum; and additional rare-earth and other elements. 14 figures.

  20. Two-phase chromium-niobium alloys exhibiting improved mechanical properties at high temperatures

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN); Takeyama, Masao (Tokyo, JP)

    1994-01-01T23:59:59.000Z

    The specification discloses chromium-niobium alloys which exhibit improved mechanical properties at high temperatures in the range of 1250.degree. C. and improved room temperature ductility. The alloys contain a Cr.sub.2 Nb-rich intermetallic phase and a Cr-rich phase with an overall niobium concentration in the range of from about 5 to about 18 at. %. The high temperature strength is substantially greater than that of state of the art nickel-based superalloys for enhanced high temperature service. Further improvements in the properties of the compositions are obtained by alloying with rhenium and aluminum; and additional rare-earth and other elements.

  1. New model predicts formation of stable high-entropy alloys | ORNL

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011RNew Visible toNew appNewMaterials

  2. F A T I G U E 2 0 0 2 HIGH-CYCLE FATIGUE OF BETA TITANIUM ALLOYS

    E-Print Network [OSTI]

    Ritchie, Robert

    F A T I G U E 2 0 0 2 HIGH-CYCLE FATIGUE OF BETA TITANIUM ALLOYS J. O. Peters*+ , G. Lütjering*, R) properties of the high-strength titanium alloys -Cez and Ti-6246 (in two distinctly different + processed and processed conditions) with the conventional + titanium alloy Ti-6Al-4V (in a + processed condition

  3. Nickel aluminide alloy for high temperature structural use

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN); Sikka, Vinod K. (Clinton, TN)

    1991-01-01T23:59:59.000Z

    The specification discloses nickel aluminide alloys including nickel, aluminum, chromium, zirconium and boron wherein the concentration of zirconium is maintained in the range of from about 0.05 to about 0.35 atomic percent to improve the ductility, strength and fabricability of the alloys at 1200.degree. C. Titanium may be added in an amount equal to about 0.2 to about 0.5 atomic percent to improve the mechanical properties of the alloys and the addition of a small amount of carbon further improves hot fabricability.

  4. Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf)

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12T23:59:59.000Z

    NiTiHf alloys have attracted considerable attention as potential high temperature Shape Memory Alloy (SMA) but the instability in transformation temperatures and significant irrecoverable strain during thermal cycling under constant stress remains a...

  5. Charged-particle and neutron-capture processes in the high-entropy wind of core-collapse supernovae.

    SciTech Connect (OSTI)

    Farouqi, K.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K.; Truran, J.W.; Physics; Univ. of Chicago; Joint Inst. for Nuclear Astrophysics; Univ. Mainz; Virtual Inst. for Nuclear Structure and Astrophysics; Max-Planck-Insti. fur Chemie; Univ. of Basel

    2010-04-01T23:59:59.000Z

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e}, and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e}, beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a {beta}-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from {beta}-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and {beta}-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low metallicity stars.

  6. CHARGED-PARTICLE AND NEUTRON-CAPTURE PROCESSES IN THE HIGH-ENTROPY WIND OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Farouqi, K.; Truran, J. W. [Department of Astrophysics and Astronomy, University of Chicago, Chicago, IL 60637 (United States); Kratz, K.-L. [HGF Virtuelles Institut fuer Kernstruktur und Nukleare Astrophysik, Universitaet Mainz, D-55128 Mainz (Germany); Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, D-55128 Mainz (Germany); Rauscher, T.; Thielemann, F.-K., E-mail: farouqi@uchicago.ed, E-mail: truran@nova.uchicago.ed, E-mail: BPfeiffe@uni-mainz.d, E-mail: k-l.Kratz@mpic.d, E-mail: Thomas.Rauscher@unibas.c, E-mail: F-K.Thielemann@unibas.c [Department of Physics, University of Basel, 4056 Basel (Switzerland)

    2010-04-01T23:59:59.000Z

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e} , and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e} , beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a beta-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from beta-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and beta-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low metallicity stars.

  7. Charged-partricle and neutron-capture processes in the high-entropy wind of core-collapse supernovae.

    SciTech Connect (OSTI)

    Farouqi, K.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K.; Truran, J. W.; Physics; Univ. of Chicago; Joint Inst. for Nuclear Astrophysics; Univ. Mainz; Virtual Inst. for Nuclear Structure and Astrophysics; Max-Planck-Inst. fur Chemie; Univ. of Basel

    2010-04-01T23:59:59.000Z

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e}, and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e}, beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a {beta}-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from {beta}-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and {beta}-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low metallicity stars.

  8. DEVELOPMENT OF A HIGH STRENGTH, HYDROGEN-RESISTANT AUSTENITIC ALLOY

    E-Print Network [OSTI]

    Chang, K.M.

    2010-01-01T23:59:59.000Z

    W. Morris, Jr. and G. Thonps: EPRI Report FP-1061, Electricbased superalloy, designated EPRI-E, of nominal composition0.3V-0.01B, and designated EPRI-T. The alloy differs from

  9. Thermomechanical Cyclic Response of TiNiPd High-Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Atli, Kadri

    2012-10-19T23:59:59.000Z

    TiNiPd high-temperature shape memory alloys (HTSMAs) have attracted considerable attention as potential solid-state actuators capable of operating at temperatures up to 500 °C, exhibiting excellent corrosion resistance, adequate ductility levels...

  10. Influence of Inelastic Phenomena on the Actuation Characteristics of High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Kumar, Parikshith K.

    2010-07-14T23:59:59.000Z

    Most e orts on High Temperature Shape Memory Alloys (HTSMAs), have focused on improving their work characteristics by thermomechanical treatment methods. However, the in uence of transformation induced plasticity (TRIP) and viscoplasticity during...

  11. Vehicle Technologies Office Merit Review 2014: High Energy Novel Cathode / Alloy Automotive Cell

    Broader source: Energy.gov [DOE]

    Presentation given by 3M at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high energy novel cathode / alloy...

  12. Iron-niobium-aluminum alloy having high-temperature corrosion resistance

    DOE Patents [OSTI]

    Hsu, Huey S.

    1988-04-14T23:59:59.000Z

    An alloy for use in high temperature sulfur and oxygen containing environments, having aluminum for oxygen resistance, niobium for sulfur resistance and the balance iron, is discussed. 4 figs., 2 tabs.

  13. Stress corrosion cracking and hydrogen embrittlement of thick section high strength low alloy steel

    E-Print Network [OSTI]

    Needham, William Donald

    1986-01-01T23:59:59.000Z

    An experimental study was conducted to evaluate the corrosion performance of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United ...

  14. Advanced nickel base alloys for high strength, corrosion applications

    DOE Patents [OSTI]

    Flinn, John E. (Idaho Falls, ID)

    1998-01-01T23:59:59.000Z

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0-20Fe, 10-30Cr, 2-12Mo, 6 max. Nb, 0.05-3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01-0.08C, less than 0.2N, 0.1 max. 0, bal. Ni.

  15. Advanced nickel base alloys for high strength, corrosion applications

    DOE Patents [OSTI]

    Flinn, J.E.

    1998-11-03T23:59:59.000Z

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0--20Fe, 10--30Cr, 2--12Mo, 6 max. Nb, 0.05--3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01--0.08C, less than 0.2N, 0.1 max. 0, bal. Ni. 3 figs.

  16. Iron-aluminum alloys having high room-temperature and method for making same

    DOE Patents [OSTI]

    Sikka, Vinod K. (Oak Ridge, TN); McKamey, Claudette G. (Knoxville, TN)

    1993-01-01T23:59:59.000Z

    Iron-aluminum alloys having selectable room-temperature ductilities of greater than 20%, high resistance to oxidation and sulfidation, resistant pitting and corrosion in aqueous solutions, and possessing relatively high yield and ultimate tensile strengths are described. These alloys comprise 8 to 9.5% aluminum, up to 7% chromium, up to 4% molybdenum, up to 0.05% carbon, up to 0.5% of a carbide former such as zirconium, up to 0.1 yttrium, and the balance iron. These alloys in wrought form are annealed at a selected temperature in the range of 700.degree. C. to about 1100.degree. C. for providing the alloys with selected room-temperature ductilities in the range of 20 to about 29%.

  17. Advanced Corrosion-Resistant Zr Alloys for High Burnup and Generation IV Applications

    SciTech Connect (OSTI)

    Arthur Motta; Yong Hwan Jeong; R.J. Comstock; G.S. Was; Y.S. Kim

    2006-10-31T23:59:59.000Z

    The objective of this collaboration between four institutions in the US and Korea is to demonstrate a technical basis for the improvement of the corrosion resistance of zirconium-based alloys in more extreme operating environments (such as those present in severe fuel duty,cycles (high burnup, boiling, aggressive chemistry) andto investigate the feasibility (from the point of view of corrosion rate) of using advanced zirconium-based alloys in a supercritical water environment.

  18. CoNiGa High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Dogan, Ebubekir

    2011-10-21T23:59:59.000Z

    Shape memory alloys (SMAs) are an important class of smart materials that have the ability to remember a shape. Current practical uses of SMAs are limited to below 100 degrees C which is the limit for the transformation temperatures of most...

  19. High strength, thermally stable, oxidation resistant, nickel-based alloy

    DOE Patents [OSTI]

    Sikka, Vinod K. (Oak Ridge, TN); Deevi, Seetharama C. (Midlothian, VA); Vought, Joseph D. (Rockwood, TN); Howell, C. Randal (Knoxville, TN)

    1999-01-01T23:59:59.000Z

    A polycrystalline alloy is composed essentially of, by weight %: 15% to 30% Mo, 3% to 10% Al, up to 10% Cr, up to 10% Fe, up to 2% Si, 0.01% to 0.2% C, 0.01% to 0.04% B, balance Ni.

  20. High-speed machining of cast iron and alloy steels for die and mold manufacturing

    E-Print Network [OSTI]

    Ozel, Tugrul

    to machining of aluminum alloys for manufacturing complicated parts used in the aircraft industry. This tech of automotive and electronic components, as well as plastic molding parts [2]. The de®nition of high conventional in cut- ting aluminum. Major advantages of high-speed machining are reported as: high material

  1. Maximum-entropy principle for static and dynamic high-field transport in semiconductors

    SciTech Connect (OSTI)

    Trovato, M. [Dipartimento di Matematica, Universita di Catania, Viale A. Doria, 95125 Catania (Italy); Reggiani, L. [Dipartimento di Ingegneria dell' Innovazione e Nanotechnology National Laboratory of CNR-INFM, Universita di Lecce, Via Arnesano s/n, 73100 Lecce (Italy)

    2006-06-15T23:59:59.000Z

    Within the maximum entropy principle we present a general theory able to provide, in a dynamical context, the macroscopic relevant variables for carrier transport under electric fields of arbitrary strength. For the macroscopic variables the linearized maximum entropy approach is developed including full-band effects within a total energy scheme. Under spatially homogeneous conditions, we construct a closed set of hydrodynamic equations for the small-signal (dynamic) response of the macroscopic variables. The coupling between the driving field and the energy dissipation is analyzed quantitatively by using an arbitrary number of moments of the distribution function. The theoretical approach is applied to n-Si at 300 K and is validated by comparing numerical calculations with ensemble Monte Carlo simulations and with experimental data.

  2. High-strength, creep-resistant molybdenum alloy and process for producing the same

    DOE Patents [OSTI]

    Bianco, Robert (Finleyville, PA); Buckman, Jr., R. William (Pittsburgh, PA); Geller, Clint B. (Pittsburgh, PA)

    1999-01-01T23:59:59.000Z

    A wet-doping process for producing an oxide-dispersion strengthened (ODS), creep-resistant molybdenum alloy is disclosed. The alloy is made by adding nitrate or acetate salts of lanthanum, cerium, thorium, or yttrium to molybdenum oxide to produce a slurry, heating the slurry in a hydrogen atmosphere to produce a powder, mixing and cold isostatically pressing the powder, sintering in a hydrogen atmosphere, and thermomechanically processing (swaging, extruding, cold drawing) the product. The ODS molybdenum alloy produced by the process contains 2-4% by volume (.about.1-4% by weight) of an oxide of lanthanum, cerium, thorium, or yttrium. The alloy has high strength and improved creep-resistance at temperatures greater than 0.55T.sub.m of molybdenum.

  3. High-strength, creep-resistant molybdenum alloy and process for producing the same

    DOE Patents [OSTI]

    Bianco, R.; Buckman, R.W. Jr.; Geller, C.B.

    1999-02-09T23:59:59.000Z

    A wet-doping process for producing an oxide-dispersion strengthened (ODS), creep-resistant molybdenum alloy is disclosed. The alloy is made by adding nitrate or acetate salts of lanthanum, cerium, thorium, or yttrium to molybdenum oxide to produce a slurry, heating the slurry in a hydrogen atmosphere to produce a powder, mixing and cold isostatically pressing the powder, sintering in a hydrogen atmosphere, and thermomechanically processing (swaging, extruding, cold drawing) the product. The ODS molybdenum alloy produced by the process contains 2--4% by volume (ca. 1--4% by weight) of an oxide of lanthanum, cerium, thorium, or yttrium. The alloy has high strength and improved creep-resistance at temperatures greater than 0.55T{sub m} of molybdenum. 10 figs.

  4. Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

    SciTech Connect (OSTI)

    Day, S D; Haslam, J J; Farmer, J C; Rebak, R B

    2007-08-10T23:59:59.000Z

    Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepared ribbons. Results show that the amorphous alloys can be exposed to 600 C for 1-hr. without losing the corrosion resistance; however, when the ribbons were exposed at 800 C for 1-hr. their localized corrosion resistance decreased significantly.

  5. Considerations of Alloy N for Fluoride Salt-Cooled High-Temperature Reactor Applications

    SciTech Connect (OSTI)

    Ren, Weiju [ORNL; Muralidharan, Govindarajan [ORNL; Wilson, Dane F [ORNL; Holcomb, David Eugene [ORNL

    2011-01-01T23:59:59.000Z

    Fluoride Salt-Cooled High-Temperature Reactors (FHRs) are a promising new class of thermal-spectrum nuclear reactors. The reactor structural materials must possess high-temperature strength and chemical compatibility with the liquid fluoride salt as well as with a power cycle fluid such as supercritical water while remaining resistant to residual air within the containment. Alloy N was developed for use with liquid fluoride salts and it possesses adequate strength and chemical compatibility up to about 700 C. A distinctive property of FHRs is that their maximum allowable coolant temperature is restricted by their structural alloy maximum service temperature. As the reactor thermal efficiency directly increases with the maximum coolant temperature, higher temperature resistant alloys are strongly desired. This paper reviews the current status of Alloy N and its relevance to FHRs including its design principles, development history, high temperature strength, environmental resistance, metallurgical stability, component manufacturability, ASME codification status, and reactor service requirements. The review will identify issues and provide guidance for improving the alloy properties or implementing engineering solutions.

  6. High permeance sulfur tolerant Pd/Cu alloy membranes

    DOE Patents [OSTI]

    Ma, Yi Hua; Pomerantz, Natalie

    2014-02-18T23:59:59.000Z

    A method of making a membrane permeable to hydrogen gas (H.sub.2.uparw.) is disclosed. The membrane is made by forming a palladium layer, depositing a layer of copper on the palladium layer, and galvanically displacing a portion of the copper with palladium. The membrane has improved resistance to poisoning by H.sub.2S compared to a palladium membrane. The membrane also has increased permeance of hydrogen gas compared to palladium-copper alloys. The membrane can be annealed at a lower temperature for a shorter amount of time.

  7. Vibration Isolation with High Strain Shape Memory Alloy Actuators: Case of the impulse disturbance

    E-Print Network [OSTI]

    Hayward, Vincent

    disturbance, while an active stage is used to aug- ment low frequency damping and provide attenuationVibration Isolation with High Strain Shape Memory Alloy Actuators: Case of the impulse disturbance disturbance on a mass to be isolated from vibrations. The vibration isolation testbed consists of a `strong

  8. High-power laser and arc welding of thorium-doped iridium alloys

    SciTech Connect (OSTI)

    David, S.A.; Liu, C.T.

    1980-05-01T23:59:59.000Z

    The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

  9. alloys: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  10. A View of Compatible Heat-Resistant Alloy and Coating Systems at High-Temperatures

    SciTech Connect (OSTI)

    Narita, Toshio [Specially Promoted Research Laboratory of Advanced Coatings, Hokkaido University, Kite-13 Nishi-8, Kita-Ku, Sapporo 060-8628 (Japan)

    2009-09-14T23:59:59.000Z

    Conventional and advanced coatings were reviewed, and it was pointed out that the coated Ni-base superalloys decreased their creep rupture life significantly at higher temperatures, and the advanced high strength superalloy became more remarkably. Concept of diffusion barrier coating system (DBC system) and their formation process was introduced, and the results obtained for several heat-resistant alloys, stainless steel (SUS310S), Ni-Mo base alloy (Hastelloy-X), and 4{sup th} generation single crystal superalloy (TMS-138) were given. It was noted that creep-rupture life of the SUS310S and Hastelloy-X with the DBC system became longer than those of the bare alloys with or without conventional {beta}-NiAl coatings. This is due to slow creep-deformation of the Re-base alloy layer as the diffusion barrier. A novel concept based on combination of superalloys and coatings was proposed, by taking both the materials science and corrosion science into consideration.

  11. alloys development-inconel alloys: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  12. A Model for High-Strain-Rate Deformation of Uranium-Niobium Alloys

    SciTech Connect (OSTI)

    F.L.Addessio; Q.H.Zuo; T.A.Mason; L.C.Brinson

    2003-05-01T23:59:59.000Z

    A thermodynamic approach is used to develop a framework for modeling uranium-niobium alloys under the conditions of high strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent plasticity, and porosity growth is presented. An implicit numerical technique is used to solve the evolution equations for the material state. Comparisons are made between the model and data for low-strain-rate loading and unloading as well as for heating and cooling experiments. Comparisons of the model and data also are made for low- and high-strain-rate uniaxial stress and uniaxial strain experiments. A uranium-6 weight percent niobium alloy is used in the comparisons of model and experiment.

  13. Grain growth behavior and high-temperature high-strain-rate tensile ductility of iridium alloy DOP-26

    SciTech Connect (OSTI)

    McKamey, C.G.; Gubbi, A.N.; Lin, Y.; Cohron, J.W.; Lee, E.H.; George, E.P.

    1998-04-01T23:59:59.000Z

    This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the new-process iridium-based DOP-26 alloy used for the Cassini space mission. This alloy was developed at Oak Ridge National Laboratory (ORNL) in the early 1980`s and is currently used by NASA for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. Included within this report are data generated on grain growth in vacuum or low-pressure oxygen environments; a comparison of grain growth in vacuum of the clad vent set cup material with sheet material; effect of grain size, test temperature, and oxygen exposure on high-temperature high-strain-rate tensile ductility; and grain growth in vacuum and high-temperature high-strain-rate tensile ductility of welded DOP-26. The data for the new-process material is compared to available old-process data.

  14. Corrosion of high temperature alloys in solar salt at 400, 500, and 680%C2%B0C.

    SciTech Connect (OSTI)

    Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth

    2013-09-01T23:59:59.000Z

    Corrosion tests at 400, 500, and 680%C2%B0C were performed using four high temperature alloys; 347SS, 321SS In625, and HA230. Molten salt chemistry was monitored over time through analysis of nitrite, carbonate, and dissolved metals. Metallography was performed on alloys at 500 and 680%C2%B0C, due to the relatively thin oxide scale observed at 400%C2%B0C. At 500%C2%B0C, corrosion of iron based alloys took the form of chromium depletion and iron oxides, while nickel based alloys also had chromium depletion and formation of NiO. Chromium was detected in relatively low concentrations at this temperature. At 680%C2%B0C, significant surface corrosion occurred with metal losses greater than 450microns/year after 1025hours of exposure. Iron based alloys formed complex iron, sodium, and chromium oxides. Some data suggests grain boundary chromium depletion of 321SS. Nickel alloys formed NiO and metallic nickel corrosion morphologies, with HA230 displaying significant internal oxidation in the form of chromia. Nickel alloys both exhibited worse corrosion than iron based alloys likely due to preferential dissolution of chromium, molybdenum, and tungsten.

  15. High Energy Novel Cathode / Alloy Automotive Cell | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHigh Efficiency Low -1 DOE0Novel

  16. High-temperature phase transformation in Cr added TiAl base alloy

    SciTech Connect (OSTI)

    Abe, E.; Niinobe, K.; Nobuki, M.; Nakamura, M.; Tsujimoto, T.

    1999-07-01T23:59:59.000Z

    The authors have investigated a microstructure evolution of a Ti-48Al-3.5Cr (in at.%) alloy at high-temperatures ({gt} 1,473K). In the alloy annealed at 1673K for 1.8ks, followed by air-cooling, a characteristic microstructure with a feathery fashion was uniformly formed. From a cooling-rate-controlling study, it was found that formation of the feathery structure is accomplished during continuous cooling from 1673K to 1573K, within the {alpha} + {gamma} two-phase region. Transmission electron microscopy revealed that the feathery structure is composed of lamellar colonies (5--10{micro}m) which are crystallographically tilted slightly (a few degree) with their neighbors. A surprising fact is that lamellae in each colony are mostly the {gamma} phase with few {alpha}{sub 2} phase less than 5% in volume. This suggests that the feathery structure is a metastable product and has not resulted from the {alpha} {r{underscore}arrow} {alpha} + {gamma} transformation above 1,573 K. Instead, the feathery structure formation should be attributed to the non-equilibrium {alpha} {r{underscore}arrow} {gamma} transformation which occurs at high-temperatures with a small degree of supercooling. The authors discuss this interesting phase transformation in terms of the {alpha} {r{underscore}arrow} {gamma} massive transformation, based on the continuous-cooling-transformation (CCT) diagram constructed for the present alloy.

  17. Hot corrosion and high temperature corrosion behavior of a new gas turbine material -- alloy 603GT

    SciTech Connect (OSTI)

    Agarwal, D.C. [Krupp VDM GmbH, Houston, TX (United States); Brill, U.; Klower, J. [Krupp VDM GmbH, Werdohl (Germany)

    1998-12-31T23:59:59.000Z

    Salt deposits encountered in a variety of high temperature processes have caused premature failures in heat exchangers and superheater tubes in pulp and paper recovery boilers, waste incinerators and coal gasifiers. Molten salt corrosion studies in both land based and air craft turbines have been the subject of intense study by many researchers. This phenomenon referred to as ``hot corrosion`` has primarily been attributed to corrosion by alkali sulfates, and there is somewhat general agreement in the literature that this is caused by either basic or acidic dissolution (fluxing) of the protective metal oxide layers by complex salt deposits containing both sulfates and chlorides. This paper describes experimental studies conducted on the hot corrosion behavior of a new Ni-Cr-Al alloy 603GT (UNS N06603) in comparison to some commercially established alloys used in gas turbine components.

  18. Corrosion and Creep of Candidate Alloys in High Temperature Helium and Steam Environments for the NGNP

    SciTech Connect (OSTI)

    Was, Gary; Jones, J. W.

    2013-06-21T23:59:59.000Z

    This project aims to understand the processes by which candidate materials degrade in He and supercritical water/steam environments characteristic of the current NGNP design. We will focus on understanding the roles of temperature, and carbon and oxygen potential in the 750-850 degree C range on both uniform oxidation and selective internal oxidation along grain boundaries in alloys 617 and 800H in supercritical water in the temperature range 500-600 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature rang 750-850 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature range 750-850 degree C over a range of oxygen and carbon potentials in helium. Combined, these studies wil elucidate the potential high damage rate processes in environments and alloys relevant to the NGNP.

  19. Microstructural Characterization and Shape Memory Response of Ni-Rich NiTiHf and NiTiZr High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Evirgen, Alper

    2014-08-14T23:59:59.000Z

    NiTiHf and NiTiZr high temperature shape memory alloys (HTSMAs) have drawn a great deal of attention as cheaper alternatives to Pt, Pd and Au alloyed NiTi-based HTSMAs while NiTiZr alloys also providing at least 20% weight reduction then its Ni...

  20. Highly mismatched crystalline and amorphous GaN(1-x)As(x) alloys in the whole composition range

    SciTech Connect (OSTI)

    Yu, K. M.; Novikov, S. V.; Broesler, R.; Demchenko, I. N.; Denlinger, J. D.; Liliental-Weber, Z.; Luckert, F.; Martin, R. W.; Walukiewicz, W.; Foxon, C. T.

    2009-08-29T23:59:59.000Z

    Alloying is a commonly accepted method to tailor properties of semiconductor materials for specific applications. Only a limited number of semiconductor alloys can be easily synthesized in the full composition range. Such alloys are, in general, formed of component elements that are well matched in terms of ionicity, atom size, and electronegativity. In contrast there is a broad class of potential semiconductor alloys formed of component materials with distinctly different properties. In most instances these mismatched alloys are immiscible under standard growth conditions. Here we report on the properties of GaN1-xAsx, a highly mismatched, immiscible alloy system that was successfully synthesized in the whole composition range using a nonequilibrium low temperature molecular beam epitaxy technique. The alloys are amorphous in the composition range of 0.17alloys with x>0.2, and to the upward movement of the valence band for alloys with x<0.2. The unique features of the band structure offer an opportunity of using GaN1-xAsx alloys for various types of solar power conversion devices.

  1. Dislocation density evolution during high pressure torsion of a nanocrystalline Ni-Fe alloy

    SciTech Connect (OSTI)

    Li, Hongqi [Los Alamos National Laboratory; Wang, Y B [NON LANL; Ho, J C [NON LANL; Cao, Y [NON LANL; Liao, X Z [NON LANL; Ringer, S P [NON LANL; Zhu, Y T [NON LANL; Zhao, Y H [NON LANL; Lavernia, E J [NON LANL

    2009-01-01T23:59:59.000Z

    High-pressure torsion (HPT) induced dislocation density evolution in a nanocrystalline Ni-20wt.%Fe alloy was investigated using X-ray diffraction and transmission electron microscopy. Results suggest that the dislocation density evolution is different from that in coarse-grained materials. An HPT process first reduces the dislocation density within nanocrystalline grains and produces a large number of dislocations located at small-angle sub grain boundaries that are formed via grain rotation and coalescence. Continuing the deformation process eliminates the sub grain boundaries but significantly increases the dislocation density in grains. This phenomenon provides an explanation of the mechanical behavior of some nanostructured materials.

  2. Phase equilibria of an Al0.5CrFeCoNiCu High Entropy Alloy

    E-Print Network [OSTI]

    Jones, N. G.; Frezza, A.; Stone, H. J.

    2014-07-27T23:59:59.000Z

    /Co/Fe with Cr exhibit multiphase regions, the solubility of Cr in each Ni/Co/Fe binary solid solutions at elevated temperatures is always significant [22,34–36]. The Fig. 4. BSEI micrographs of Al0.5CrFeCoNiCu following 1000 h heat treatment at (a) 700 1C, (b...

  3. alloy nimonic 80a: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 18 HIGHLY...

  4. alloying primenenie obratimogo: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  5. alloys otrabotka tekhnologii: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  6. alloys vikoristannya modelej: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  7. alloys vliyanie vysokoskorostnogo: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  8. alloys tochechnye defekty: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  9. alloy 800h: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  10. alloy su31: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 18 HIGHLY...

  11. Oxidation Kinetics of High Strength Low Alloy Steels at Elevated Temperatures

    E-Print Network [OSTI]

    Talekar, Anjali

    2009-01-01T23:59:59.000Z

    selection, and physical metallurgy / E. E. Fletcher AlloyingIntroduction to Physical Metallurgy, McGraw-Hill, inc. ASM,

  12. Singapore Welding Society Newsletter, September 1999 Problems in Welding of High Strength Aluminium Alloys

    E-Print Network [OSTI]

    Zhou, Wei

    Aluminium Alloys Wei Zhou Nanyang Technological University, Singapore E-mail: WZhou@Cantab.Net Pure aluminium has very low strength, yet many of its alloys are stronger than ordinary structural steels. Some aluminium alloys especially those in the 5XXX and 7XXX series (e.g., 5083, 7020, and 7039) are so strong

  13. Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation

    SciTech Connect (OSTI)

    J. Douglas Way; Paul M. Thoen

    2006-08-31T23:59:59.000Z

    This report summarizes progress made during the a three year University Coal Research grant (DEFG26-03NT41792) at the Colorado School of Mines. The period of performance was September 1, 2003 through August of 2006. We made excellent progress toward our goal of contributing to the development of high productivity, sulfur tolerant composite metal membranes for hydrogen production and membrane reactors. Composite Pd and Pd alloy metal membranes with thin metal films (1-7 {micro}m) were prepared on porous stainless steel and ceramic supports that meet or exceed the DOE 2010 and 2015 pure hydrogen flux targets at differential pressure of only 20 psi. For example, a 2 {micro}m pure Pd membrane on a Pall AccuSep{reg_sign} substrate achieved an ideal H{sub 2}/N{sub 2} separation factor of over 6000, with a pure hydrogen flux of 210 SCFH/ft{sup 2} at only 20 psig feed pressure. Similar performance was achieved with a Pd{sub 80}Au{sub 20} composite membrane on a similar stainless steel substrate. Extrapolating the pure hydrogen flux of this PdAu membrane to the DOE Fossil Energy target conditions of 150 psia feed pressure and 50 psia permeate pressure gives a value of 508 SCFH/ft{sup 2}, exceeding the 2015 target. At these thicknesses, it is the support cost that will dominate the cost of a large scale module. In a direct comparison of FCC phase PdCu and PdAu alloys on identical supports, we showed that a Pd{sub 85}Au{sub 15} (mass %) alloy membrane is not inhibited by CO, CO{sub 2}, or steam present in a water-gas shift feed mixture at 400 C, has better resistance to sulfur than a Pd{sub 94}Cu{sub 6} membrane, and has over twice the hydrogen permeance.

  14. Solid State Joining of High Temperature Alloy Tubes for USC and Heat-Exchanger Systems

    SciTech Connect (OSTI)

    Bimal Kad

    2011-12-31T23:59:59.000Z

    The principal objective of this project was to develop materials enabling joining technologies for use in forward looking heat-exchanger fabrication in Brayton cycle HIPPS, IGCC, FutureGen concepts capable of operating at temperatures in excess of 1000{degree}C as well as conventional technology upgrades via Ultra Super-Critical (USC) Rankine-cycle boilers capable of operating at 760{degree}C (1400F)/38.5MPa (5500psi) steam, while still using coal as the principal fossil fuel. The underlying mission in Rankine, Brayton or Brayton-Rankine, or IGCC combined cycle heat engine is a steady quest to improving operating efficiency while mitigating global environmental concerns. There has been a progressive move to higher overall cycle efficiencies, and in the case of fossil fuels this has accelerated recently in part because of concerns about greenhouse gas emissions, notably CO{sub 2}. For a heat engine, the overall efficiency is closely related to the difference between the highest temperature in the cycle and the lowest temperature. In most cases, efficiency gains are prompted by an increase in the high temperature, and this in turn has led to increasing demands on the materials of construction used in the high temperature end of the systems. Our migration to new advanced Ni-base and Oxide Dispersion Strengthened (ODS) alloys poses significant fabrication challenges, as these materials are not readily weldable or the weld performs poorly in the high temperature creep regime. Thus the joining challenge is two-fold to a) devise appropriate joining methodologies for similar/dissimilar Ni-base and ODS alloys while b) preserving the near baseline creep performance in the welded region. Our program focus is on solid state joining of similar and dissimilar metals/alloys for heat exchanger components currently under consideration for the USC, HIPPS and IGCC power systems. The emphasis is to manipulate the joining methods and variables available to optimize joint creep performance compared to the base material creep performance. Similar and dissimilar butt joints were fabricated of MA956, IN740 alloys and using inertia welding techniques. We evaluated joining process details and heat treatments and its overall effect on creep response. Fixed and incrementally accelerated temperature creep tests were performed for similar and dissimilar joints and such incremental creep life data is compiled and reported. Long term MA956-MA556 joint tests indicate a firm 2Ksi creep stress threshold performance at 850{degree}C with a maximum exposure of over 9725 hours recorded in the current program. A Larsen Miller Parameter (LMP) of 48.50 for a 2Ksi test at 850{degree}C was further corroborated with tests at 2Ksi stress at 900{degree}C yielding a LMP=48.80. Despite this threshold the joints exhibit immense temperature sensitivity and fail promptly when test temperature raised above 900{degree}C. In comparison the performance of dissimilar joints was inferior, perhaps dictated by the creep characteristics of the mating nickel-base alloys. We describe a parametric window of joint development, and post weld heat treatment (PWHT) in dissimilar joints with solid solution (IN601, IN617) and precipitate strengthened (IN740) materials. Some concerns are evident regarding the diffusion of aluminum in dissimilar joints during high temperature recrystallization treatments. It is noted that aggressive treatments rapidly deplete the corrosion protecting aluminum reservoir in the vicinity of the joint interface. Subsequently, the impact of varying PWHT has been evaluated in the context on ensuing creep performance.

  15. On the amorphization behavior and hydrogenation performance of high-energy ball-milled Mg{sub 2}Ni alloys

    SciTech Connect (OSTI)

    Kou, Hongchao; Hou, Xiaojiang; Zhang, Tiebang, E-mail: tiebangzhang@nwpu.edu.cn; Hu, Rui; Li, Jinshan; Xue, Xiangyi

    2013-06-15T23:59:59.000Z

    Amorphous Mg{sub 2}Ni alloy was prepared by high energy ball-milling starting with polycrystalline Mg{sub 2}Ni which was prepared with the help of a metallurgy method by using a SPEX 8000D mill. The microstructural and phase structure characterization of the prepared materials was performed via scanning electron microscopy, transition electron microscope and X-ray diffraction. The thermal stabilities were investigated by differential scanning calorimetry. The apparent activation energies were determined by means of the Kissinger method. The first and second crystallization reactions take place at ? 255 °C and ? 410 °C, and the corresponding activation energy of crystallization is E{sub a1} = 276.9 and E{sub a2} = 382.4 kJ/mol, respectively. At 3 MPa hydrogen pressure and 250 °C, the hydrogen absorption capacities of crystalline, partially and fully amorphous Mg{sub 2}Ni alloy are 2.0 wt.%, 3.2 wt.% and 3.5 wt.% within 30 min, respectively. - Graphical Abstract: We mainly focus on the amorphization behavior of crystalline Mg{sub 2}Ni alloy in the high energy ball-milling process and the crystallization behavior of the amorphous Mg{sub 2}Ni alloy in a follow-up heating process. The relationship of milling, microstructure and hydrogenation properties is established and explained by models. - Highlights: • Amorphous Mg{sub 2}Ni has been obtained by high energy ball milling the as-cast alloy. • The amorphization behavior of polycrystalline Mg{sub 2}Ni is presented. • The crystallization behavior of the amorphous Mg{sub 2}Ni alloy is illustrated. • Establish the relationship of milling, microstructure and hydrogenation properties.

  16. High swelling rates observed in neutron-irradiated V-Cr and V-Si binary alloys

    SciTech Connect (OSTI)

    Garner, F.A.; Gelles, D.S. (Pacific Northwest Lab., Richland, WA (United States)); Takahashi, H.; Ohnuki, S.; Kinoshita, H. (Hokkaido Univ., Sapporo (Japan)); Loomis, B.A. (Argonne National Lab., IL (United States))

    1991-11-01T23:59:59.000Z

    Additions of 5 to 14 wt% chromium to vanadium lead to very large swelling rates during neutron irradiation of the binary alloys, with swelling increasing strongly at higher irradiation temperatures. Addition of 2 wt% silicon to vanadium also leads to very large swelling rates but swelling decreases with increasing irradiation temperature. Addition of 1 wt% zirconium does not yield high swelling rates, however.

  17. MELE: Maximum Entropy Leuven Estimators

    E-Print Network [OSTI]

    Paris, Quirino

    2001-01-01T23:59:59.000Z

    of the Generalized Maximum Entropy Estimator of the Generaland Douglas Miller, Maximum Entropy Econometrics, Wiley andCalifornia Davis MELE: Maximum Entropy Leuven Estimators by

  18. Iron-aluminum alloys having high room-temperature and method for making same

    DOE Patents [OSTI]

    Sikka, V.K.; McKamey, C.G.

    1993-08-24T23:59:59.000Z

    A wrought and annealed iron-aluminum alloy is described consisting essentially of 8 to 9.5% aluminum, an effective amount of chromium sufficient to promote resistance to aqueous corrosion of the alloy, and an alloying constituent selected from the group of elements consisting of an effective amount of molybdenum sufficient to promote solution hardening of the alloy and resistance of the alloy to pitting when exposed to solutions containing chloride, up to about 0.05% carbon with up to about 0.5% of a carbide former which combines with the carbon to form carbides for controlling grain growth at elevated temperatures, and mixtures thereof, and the balance iron, wherein said alloy has a single disordered [alpha] phase crystal structure, is substantially non-susceptible to hydrogen embrittlement, and has a room-temperature ductility of greater than 20%.

  19. Temperture and composition dependence of the high flux plasma sputtering yield of Cu-Li binary alloys

    SciTech Connect (OSTI)

    Krauss, A.R.; Mendelsohn, M.H.; Gruen, D.M.; Conn, R.W.; Goebel, D.M.; Hirooka, Y.; Leung, W.K.; Bohdansky, J.

    1986-01-01T23:59:59.000Z

    High flux deuterium plasma sputtering and ion beam experiments have been performed on Cu-Li alloys to determine if the reduction in copper erosion previously predicted and observed in low flux ion beam experiments occurs at particle fluxes representative of an RFP first wall or tokamak limiter. Partial sputtering yields of the copper and lithium components have been measured as a function of alloy composition and sample temperature using optical plasma emission spectroscopy, weight loss and catcher foil techniques. It is found that the lithium sputtering yield increases with increasing sample temperature while the copper yield decreases by as much as two orders of magnitude. The temperature required to obtain the reduction in copper erosion is found to be a function of bulk lithium concentration. Consequences of these experimental results for anticipated erosion/redeposition properties are calculated, and the Cu-Li alloy in found to compare favorably with conventional low-Z materials.

  20. Vehicle Technologies Office Merit Review 2014: Alloy Development for High-Performance Cast Crankshafts

    Broader source: Energy.gov [DOE]

    Presentation given by Argonne National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about applied alloy...

  1. Study of SiCnickel alloy bonding for high temperature applications M.L. Hattalia,, S. Valettea, F. Ropitalc, G. Stremsdoerfera, N. Mesratib, D. Trheuxa

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Study of SiC­nickel alloy bonding for high temperature applications M.L. Hattalia,, S. Valettea, F). In some cases a thin coating on the ceramic or the alloy by the electroless JetMétalTM process has been used. Often used in brazing, nickel, when added to silicon carbide, usually give silicides

  2. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOE Patents [OSTI]

    Maziasz, Philip J. (Oak Ridge, TN); Goodwin, Gene M. (Lenoir City, TN); Liu, Chain T. (Oak Ridge, TN)

    1996-01-01T23:59:59.000Z

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding.

  3. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOE Patents [OSTI]

    Maziasz, P.J.; Goodwin, G.M.; Liu, C.T.

    1996-08-13T23:59:59.000Z

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding. 13 figs.

  4. Compatibility of Inconel 617 alloy with eutectic fluoride salts at high temperatures

    SciTech Connect (OSTI)

    Luo, A.; Jacobson, D.L. (Department of Chemical, Bio Materials Engineering, Arizona State University, Tempe, Arizona 85287-6006 (United States)); Ponnappan, R. (Universal Energy Systems, Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432 (United States))

    1993-01-10T23:59:59.000Z

    Thermal Energy Storage (TES) capsules made of Inconel 617 alloy were filled with high purity eutectic fluoride salts and thermally cycled at eutectic temperature [plus minus]100 K for a period of up to 50,000 hours. The containment life performance characteristics with fluoride salts were examined. The depletion of Al and Cr near the inner edges was found. Atomic Absorption Spectroscopy revealed that both Al and Cr were dissolved in the fluoride salts at high temperatures. The changes in melting temperature and heat of fusion of fluoride salts during thermal cycling were measured with Thermal Differential Analysis. A modified diffusion equation for a one-dimensional semi-infinite bar was applied to the depletion of Al on the interior surfaces of the containers. Good agreement was obtained between the analysis and the measured concentration profiles. The present study suggests that the corrosion was a diffusion controlled process and an expected lifetime of 5--7 years is reasonable and predictable based upon the limited diffusion processes.

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

    SciTech Connect (OSTI)

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

    2014-04-01T23:59:59.000Z

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

  6. Ultrasonic properties of low solvus high refractory (LSHR) super alloy disk material

    SciTech Connect (OSTI)

    Na, Jeong K. [University of Dayton Research Institute, 300 College Park, Dayton, OH 45469 (United States); Blodgett, Mark [Air Force Research Laboratory (AFRL/RXLP) Wright-Patterson AFB, OH 45433 (United States)

    2011-06-23T23:59:59.000Z

    Measurements are made for ultrasonic linear and nonlinear properties of the powder metallurgy disk alloy LSHR material designed with a relatively low {gamma}' precipitate solvus temperature and high refractory element content. This allows versatile heat treatment processing which results in high tensile, creep and fatigue properties depending on the grain size controlled through proper selection of solution heat treatment temperatures relative to the {gamma}' precipitate solvus temperature. Sound velocity and attenuation for both longitudinal and shear modes at various frequencies from 5 to 20 MHz help to identify and quantify the size of transition zone nondestructively between the small grain ({approx}10 {mu}m) and the large grain ({approx}100 {mu}m) zones. The shear wave velocity measurements taken by aligning the transducer polarization direction parallel and perpendicular to the grain transition direction reveal some results that we do not fully understand at this time and will be the basis of future research. Similarly, measurements of the acoustic nonlinearity parameter show some variations that may originate from uncertain sources.

  7. Entanglement entropy and entropy production in the Color Glass Condensate framework

    E-Print Network [OSTI]

    Alex Kovner; Michael Lublinsky

    2015-06-17T23:59:59.000Z

    We compute the entanglement entropy of soft gluons in the wave function of a fast moving hadron and discuss its basic properties. We also derive the expression for entropy production in a high energy hadronic collision within the Color Glass formalism. We show that long range rapidity correlations give negative contribution to the production entropy. We calculate the (naturally defined) temperature of the produced system of particles, and show that it is proportional to the average transverse momentum of the produced particles.

  8. Entanglement entropy and entropy production in the Color Glass Condensate framework

    E-Print Network [OSTI]

    Kovner, Alex

    2015-01-01T23:59:59.000Z

    We compute the entanglement entropy of soft gluons in the wave function of a fast moving hadron and discuss its basic properties. We also derive the expression for entropy production in a high energy hadronic collision within the Color Glass formalism. We show that long range rapidity correlations give negative contribution to the production entropy. We calculate the (naturally defined) temperature of the produced system of particles, and show that it is proportional to the average transverse momentum of the produced particles.

  9. Molecular beam epitaxy of GaNAs alloys with high As content for potential photoanode applications in hydrogen production

    SciTech Connect (OSTI)

    Novikov, S. V.; Staddon, C. R.; Foxon, C. T.; Yu, K. M.; Broesler, R.; Hawkridge, M.; Liliental-Weber, Z.; Walukiewicz, W.; Denlinger, J.; Demchenko, I.

    2009-10-06T23:59:59.000Z

    The authors have succeeded in growing GaN1?xAsx alloys over a large composition range (0 < x < 0.8) by plasma-assisted molecular beam epitaxy. The enhanced incorporation of As was achieved by growing the films with high As{sub 2} flux at low (as low as 100 C) growth temperatures, which is much below the normal GaN growth temperature range. Using x-ray and transmission electron microscopy, they found that the GaNAs alloys with high As content x > 0.17 are amorphous. Optical absorption measurements together with x-ray absorption and emission spectroscopy results reveal a continuous gradual decrease in band gap from -3.4 to < 1 eV with increasing As content. The energy gap reaches its minimum of -0.8 eV at x - 0.8. The composition dependence of the band gap of the crystalline GaN{sub 1?x}As{sub x} alloys follows the prediction of the band anticrossing model (BAC). However, our measured band gap of amorphous GaN{sub 1?x}As{sub x} with 0.3 < x < 0.8 are larger than that predicted by BAC. The results seem to indicate that for this composition range the amorphous GaN{sub 1?x}As{sub x} alloys have short-range ordering that resembles random crystalline GaN{sub 1?x}As{sub x} alloys. They have demonstrated the possibility of the growth of amorphous GaN{sub 1?x}As{sub x} layers with variable As content on glass substrates

  10. Processing, Microstructure and Creep Behavior of Mo-Si-B-Based Intermetallic Alloys for Very High Temperature Structural Applications

    SciTech Connect (OSTI)

    Vijay Vasudevan

    2008-03-31T23:59:59.000Z

    This research project is concerned with developing a fundamental understanding of the effects of processing and microstructure on the creep behavior of refractory intermetallic alloys based on the Mo-Si-B system. In the first part of this project, the compression creep behavior of a Mo-8.9Si-7.71B (in at.%) alloy, at 1100 and 1200 C was studied, whereas in the second part of the project, the constant strain rate compression behavior at 1200, 1300 and 1400 C of a nominally Mo-20Si-10B (in at.%) alloy, processed such as to yield five different {alpha}-Mo volume fractions ranging from 5 to 46%, was studied. In order to determine the deformation and damage mechanisms and rationalize the creep/high temperature deformation data and parameters, the microstructure of both undeformed and deformed samples was characterized in detail using x-ray diffraction, scanning electron microscopy (SEM) with back scattered electron imaging (BSE) and energy dispersive x-ray spectroscopy (EDS), electron back scattered diffraction (EBSD)/orientation electron microscopy in the SEM and transmission electron microscopy (TEM). The microstructure of both alloys was three-phase, being composed of {alpha}-Mo, Mo{sub 3}Si and T2-Mo{sub 5}SiB{sub 2} phases. The values of stress exponents and activation energies, and their dependence on microstructure were determined. The data suggested the operation of both dislocation as well as diffusional mechanisms, depending on alloy, test temperature, stress level and microstructure. Microstructural observations of post-crept/deformed samples indicated the presence of many voids in the {alpha}-Mo grains and few cracks in the intermetallic particles and along their interfaces with the {alpha}-Mo matrix. TEM observations revealed the presence of recrystallized {alpha}-Mo grains and sub-grain boundaries composed of dislocation arrays within the grains (in Mo-8.9Si-7.71B) or fine sub-grains with a high density of b = 1/2<111> dislocations (in Mo-20Si-10B), which are consistent with the values of the respective stress exponents and activation energies that were obtained and provide confirmatory evidence for the operation of diffusional (former alloy) or dislocation (latter alloy) creep mechanisms. In contrast, the intermetallic phases contained very few dislocations, but many cracks. The relative contributions of the {alpha}-Mo and the intermetallic particles to the overall deformation process, including their individual and collective dependence on temperature and strain rate are discussed in light of the present results and those from previous reports.

  11. Effect of oxygen potential on high temperature crack growth in alloy 617

    E-Print Network [OSTI]

    Benz, Julian K

    2009-01-01T23:59:59.000Z

    The effect of oxygen partial pressure on crack growth rates in Alloy 617 has been studied using both static and fatigue loading at 650°C. Tests were conducted at a constant stress intensity factor, K, for static loading ...

  12. Computational Thermodynamics of CoNiGa High Temperature Shape Memory Alloys 

    E-Print Network [OSTI]

    Chari, Arpita

    2012-10-19T23:59:59.000Z

    for the present work. In this work, a thermodynamic model of the ternary system is calculated based on the CALPHAD approach, to investigate the thermodynamic properties, phase stability and shape memory properties of these alloys. The CALPHAD approach is a...

  13. Solid state thin film battery having a high temperature lithium alloy anode

    DOE Patents [OSTI]

    Hobson, David O. (Oak Ridge, TN)

    1998-01-01T23:59:59.000Z

    An improved rechargeable thin-film lithium battery involves the provision of a higher melting temperature lithium anode. Lithium is alloyed with a suitable solute element to elevate the melting point of the anode to withstand moderately elevated temperatures.

  14. Computational Thermodynamics of CoNiGa High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Chari, Arpita

    2012-10-19T23:59:59.000Z

    Alloys (HTSMAs), with possible applications in the aerospace and automotive industries. Although the CoNiGa system shows significant promise for its use as HTSMAs, limited studies are available on them. Hence, a more intensive investigation...

  15. PVD synthesis and high-throughput property characterization of Ni?Fe?Cr alloy libraries

    SciTech Connect (OSTI)

    Rar, A.; Frafjord, J.J.; Fowlkes, Jason D.; Specht, E.D.; Rack, P.D.; Santella, M.L.; Bei, H.; George, E.P.; Pharr, G.M. (Tennessee-K); (Tennessee-K); (ORNL)

    2010-11-10T23:59:59.000Z

    Three methods of alloy library synthesis, thick-layer deposition followed by interdiffusion, composition-spread codeposition and electron-beam melting of thick deposited layers, have been applied to Ni-Fe-Cr ternary and Ni-Cr binary alloys. Structural XRD mapping and mechanical characterization by means of nanoindentation have been used to characterize the properties of the libraries. The library synthesis methods are compared from the point of view of the structural and mechanical information they can provide.

  16. Electrodeposition of high Mo content Ni-Mo alloys under forced convection

    SciTech Connect (OSTI)

    Podlaha, E.J.; Matlosz, M.; Landolt, D. (Ecole Polytechnique Federale de Lausanne, Lausanee (Switzerland). Dept. des materiaux)

    1993-10-01T23:59:59.000Z

    Bright, compact, adherent, metallic Ni-Mo alloys, containing over 48 wt % Mo have been electrodeposited from an aqueous solution. The Mo content, which is the highest achieved so far in induced codeposition of Ni-Mo, was determined by X-ray fluorescence spectroscopy. The absence of oxygen was verified by Auger electron spectroscopy. Electrodeposition experiments were performed on rotating cylinder electrodes and demonstrate that the Mo content of the alloy is strongly influenced by convective transport.

  17. Alumina-forming Austenitic Alloys Licensed | ORNL

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

    powder metal stainless steels and specialty alloys including high temperature (iron-nickel-cobalt base), stainless, superior corrosion resistant, controlled expansion alloys,...

  18. High thermoelectric performance BiSbTe alloy with unique low-dimensional structure

    SciTech Connect (OSTI)

    Xie Wenjie [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634-0978 (United States); Tang Xinfeng; Yan Yonggao; Zhang Qingjie [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Tritt, Terry M. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634-0978 (United States)

    2009-06-01T23:59:59.000Z

    We report a detailed description of an innovative route of a melt spinning (MS) technique combined with a subsequent spark plasma sintering process in order to obtain high performance p-type Bi{sub 0.52}Sb{sub 1.48}Te{sub 3} bulk material, which possesses a unique low-dimensional structure. The unique structure consists of an amorphous structure, 5-15 nm fine nanocrystalline regions, and coherent interfaces between the resulting nanocrystalline regions. Measurements of the thermopower, electrical conductivity, and thermal conductivity have been performed over a range of temperature of 300-400 K. We found that MS technique can give us considerable control over the resulting nanostructure with good thermal stability during the temperature range of 300-400 K and this unique structure can effectively adjust the transport of phonons and electrons, in a manner such that it is beneficial to the overall thermoelectric performance of the material, primarily a reduction in the lattice thermal conductivity. Subsequently, this results in a maximum figure of merit ZT value of 1.56 at 300 K for p-type Bi{sub 0.52}Sb{sub 1.48}Te{sub 3} bulk material. This ZT value is over a 50% improvement of that of the state of the art commercial Bi{sub 2}Te{sub 3} materials. We also report results of thermal cycling of this material for over one hundred cycles between 300-400 K. Our work offers an innovative route for developing high performance bismuth telluride based alloys and devices, which have even broader prospects for commercial applications. This technique may also be applicable to other thermoelectric materials.

  19. alloys aa2024-t351 aa6013-t6: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 18 HIGHLY...

  20. alloys c-103 cb-1zr: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  1. alniy chill-zone alloys: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  2. alloying ni33 ti67: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  3. alloy ni70mo17cr7fe5: Topics by E-print Network

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

    high strength aluminum alloys. The expense and Aluminum Alloys Exposure to a moist environment degrades the fatigue resistance of all aluminum alloys Acton, Scott 16 HIGHLY...

  4. PdAgAu alloy with high resistance to corrosion by H{sub 2}S

    SciTech Connect (OSTI)

    Braun, Fernando; Miller, James B.; Gellman, Andrew J.; Tarditi, Ana M.; Fleutot, Benoit; Petro, Kondratyuk, Cornaglia, Laura M

    2012-12-01T23:59:59.000Z

    PdAgAu alloy films were prepared on porous stainless steel supports by sequential electroless deposition. Two specific compositions, Pd{sub 83}Ag{sub 2}Au{sub 15} and Pd{sub 74}Ag{sub 14}Au{sub 12}, were studied for their sulfur tolerance. The alloys and a reference Pd foil were exposed to 1000 H{sub 2}S/H{sub 2} at 623 K for periods of 3 and 30 hours. The microstructure, morphology and bulk composition of both nonexposed and H{sub 2}S-exposed samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). XRD and SEM analysis revealed time-dependent growth of a bulk Pd{sub 4}S phase on the Pd foil during H{sub 2}S exposure. In contrast, the PdAgAu ternary alloys displayed the same FCC structure before and after H{sub 2}S exposure. In agreement with the XRD and SEM results, sulfur was not detected in the bulk of either ternary alloy samples by EDS, even after 30 hours of H{sub 2}S exposure. X-ray photoelectron spectroscopy (XPS) depth profiles were acquired for both PdAgAu alloys after 3 and 30 hours of exposure to characterize sulfur contamination near their surfaces. Very low S 2p and S 2s XPS signals were observed at the top-surfaces of the PdAgAu alloys, and those signals disappeared before the etch depth reached ~ 10 nm, even for samples exposed to H{sub 2}S for 30 hours. The depth profile analyses also revealed silver and gold segregation to the surface of the alloys; preferential location of Au on the alloys surface may be related to their resistance to bulk sulfide formation. In preliminary tests, a PdAgAu alloy membrane displayed higher initial H{sub 2} permeability than a similarly prepared pure Pd sample and, consistent with resistance to bulk sulfide formation, lower permeability loss in H{sub 2}S than pure Pd.

  5. High plasma-flux elevated temperature sputtering of Cu-Li alloys

    SciTech Connect (OSTI)

    Krauss, A.R.; Gruen, D.M.; Mendelsohn, M.H.; Conn, R.; Goebel, D.; Hirooka, Y.; Leung, K.

    1986-01-01T23:59:59.000Z

    Copper-lithium alloys ranging in composition from 3 to 12 at. % Li have been exposed to sputtering by 3 x 10/sup 16/ - 6 x 10/sup 17/ 100 eV He+/cm/sup 2/-sec at temperatures of 300 to 500/sup 0/C at the UCLA PISCES plasma device. Weight loss and optical spectroscopy techniques were used to determine the sputtering-induced erosion of the binary alloys relative to pure copper. It was found that the weight loss of the alloy and the amount of copper in the plasma as measured by emission spectroscopy never exceeded that of pure copper and in some cases was reduced by a factor of five or more. Post-irradiation analysis by Auger electron spectroscopy and scanning electron microscopy show a correlation between lithium surface depletion, surface roughening, weight loss, and partial erosion yields as measured by plasma emission spectroscopy.

  6. X-ray-induced dissociation of H.sub.2O and formation of an O.sub.2-H.sub.2 alloy at high pressure

    DOE Patents [OSTI]

    Mao, Ho-kwang (Washington, DC); Mao, Wendy L. (Washington, DC)

    2011-11-29T23:59:59.000Z

    A novel molecular alloy of O.sub.2 and H.sub.2 and a method of producing such a molecular alloy are provided. When subjected to high pressure and extensive x-radiation, H.sub.2O molecules cleaved, forming O--O and H--H bonds. In the method of the present invention, the O and H framework in ice VII was converted into a molecular alloy of O.sub.2 and H.sub.2. X-ray diffraction, x-ray Raman scattering, and optical Raman spectroscopy demonstrate that this crystalline solid differs from previously known phases.

  7. Experimental Analysis and Numerical Simulation of Tensile Behaviour of TiNi Shape Memory Alloy Fibres Reinforced Epoxy Matrix Composite at High Temperatures

    SciTech Connect (OSTI)

    Sahli, M. L.; Necib, B. [Mechanics Laboratory, Faculty of Engineering Sciences, University Mentouri Constantine, 25000 (Algeria)

    2011-05-04T23:59:59.000Z

    The shape memory alloys (SMA) possess both sensing and actuating functions due to their shape memory effect, pseudo-elasticity, high damping capability and other remarkable properties. Combining the SMA with other materials can create intelligent or smart composites. The epoxy resin composites filled with TiNi alloys fibres were fabricated and their mechanical properties have been investigated. In this study, stress/strain relationships for a composite with embedded shape memory materials (SMA) fibres are presented. The paper illustrates influence of the SMA fibres upon changes in mechanical behaviour of a composite plate with the SMA components, firstly and secondly, the actuating ability and reliability of shape memory alloy hybrid composites.

  8. Experimental study of high energy electron interactions in a superconducting aluminum alloy resonant bar

    E-Print Network [OSTI]

    M. Barucci; M. Bassan; B. Buonomo; G. Cavallari; E. Coccia; S. D'Antonio; V. Fafone; C. Ligi; L. Lolli; A. Marini; G. Mazzitelli; G. Modestino; G. Pizzella; L. Quintieri; L. Risegari; A. Rocchi; F. Ronga; P. Valente; G. Ventura; S. M. Vinko

    2009-01-09T23:59:59.000Z

    Peak amplitude measurements of the fundamental mode of oscillation of a suspended aluminum alloy bar hit by an electron beam show that the amplitude is enhanced by a factor ~3.5 when the material is in the superconducting state. This result is consistent with the cosmic ray observations made by the resonant gravitational wave detector NAUTILUS, made of the same alloy, when operated in the superconducting state. A comparison of the experimental data with the predictions of the model describing the underlying physical process is also presented.

  9. Earth's extensive entropy bound

    E-Print Network [OSTI]

    A. M. Lisewski

    2012-12-20T23:59:59.000Z

    The possibility of planetary mass black hole production by crossing entropy limits is addressed. Such a possibility is given by pointing out that two geophysical quantities have comparable values: first, Earth's total negative entropy flux integrated over geological time and, second, its extensive entropy bound, which follows as a tighter bound to the Bekenstein limit when entropy is an extensive function. The similarity between both numbers suggests that the formation of black holes from planets may be possible through a strong fluctuation toward thermodynamic equilibrium which results in gravothermal instability and final collapse. Briefly discussed are implications for the astronomical observation of low mass black holes and for Fermi's paradox.

  10. Solid state thin film battery having a high temperature lithium alloy anode

    DOE Patents [OSTI]

    Hobson, D.O.

    1998-01-06T23:59:59.000Z

    An improved rechargeable thin-film lithium battery involves the provision of a higher melting temperature lithium anode. Lithium is alloyed with a suitable solute element to elevate the melting point of the anode to withstand moderately elevated temperatures. 2 figs.

  11. High post-irradiation ductility thermomechanical treatment for precipitation strengthened austenitic alloys

    DOE Patents [OSTI]

    Laidler, James J. (Richland, WA); Borisch, Ronald R. (Kennewick, WA); Korenko, Michael K. (Rockville, MD)

    1982-01-01T23:59:59.000Z

    A method for improving the post-irradiation ductility is described which prises a solution heat treatment following which the materials are cold worked. They are included to demonstrate the beneficial effect of this treatment on the swelling resistance and the ductility of these austenitic precipitation hardenable alloys.

  12. Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

    SciTech Connect (OSTI)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14T23:59:59.000Z

    Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening) .

  13. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    SciTech Connect (OSTI)

    Lewis, Amanda; Zhao, Hongbin; Hopkins, Scott

    2014-09-30T23:59:59.000Z

    This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

  14. High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances

    SciTech Connect (OSTI)

    K. Coulter

    2010-12-31T23:59:59.000Z

    The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% drop in flux when sulfur was added to the gas mixture and the flux was completely recovered when the sulfur flow was stopped. IdaTech tested binary and ternary membranes on a simulated flue gas stream and experienced significant difficulty in mounting and testing the sputter deposited membranes. IdaTech was able to successfully test PdAu and PdAuPt membranes and saw similar sulfur tolerance to what TDA found. The Program met all the deliverables on schedule and on budget. Over ten presentations at national and international conferences were made, four papers were published (two in progress) in technical journals, and three students (2 at GT and 1 at CSM) completed their doctorates using results generated during the course of the program. The three major findings of program were; (1) the DFT modeling was verified as a predictive tool for the permeability of Pd based ternary alloys, (2) while magnetron sputtering is useful in precisely fabricating binary and ternary alloys, the mechanical durability of membranes fabricated using this technique are inferior compared to cold rolled membranes and this preparation method is currently not ready for industrial environments, (3) based on both modeling and experimental verification in pure gas and mixed gas environments PdAu and PdAuPt alloys were found to have the combination of the highest permeability and tolerance to sulfur.

  15. Ductile transplutonium metal alloys

    DOE Patents [OSTI]

    Conner, W.V.

    1981-10-09T23:59:59.000Z

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as souces of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

  16. Standard practice for evaluation of disbonding of bimetallic stainless alloy/steel plate for use in high-pressure, high-temperature refinery hydrogen service

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2001-01-01T23:59:59.000Z

    1.1 This practice covers a procedure for the evaluation of disbonding of bimetallic stainless alloy/steel plate for use in refinery high-pressure/high-temperature (HP/HT) gaseous hydrogen service. It includes procedures to (1) produce suitable laboratory test specimens, (2) obtain hydrogen charging conditions in the laboratory that are similar to those found in refinery HP/HT hydrogen gas service for evaluation of bimetallic specimens exposed to these environments, and (3) perform analysis of the test data. The purpose of this practice is to allow for comparison of data among test laboratories on the resistance of bimetallic stainless alloy/steels to hydrogen-induced disbonding (HID). 1.2 This practice applies primarily to bimetallic products fabricated by weld overlay of stainless alloy onto a steel substrate. Most of the information developed using this practice has been obtained for such materials. The procedures described herein, may also be appropriate for evaluation of hot roll bonded, explosive bonded...

  17. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    DOE Patents [OSTI]

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03T23:59:59.000Z

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  18. Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

    SciTech Connect (OSTI)

    Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro (Brazil); Alho, B. P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 Rio de Janeiro (Brazil); Carvalho, G. [Laboratório Nacional de Luz Sincroton—LNLS, 13083-970 Campinas, São Paulo (Brazil); Magnus, A.

    2014-10-14T23:59:59.000Z

    We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.

  19. A high-entropy wind r-process study based on nuclear-structure quantities from the new finite-range droplet model FRDM(2012)

    E-Print Network [OSTI]

    Karl-Ludwig Kratz; Khalil Farouqi; Peter Möller

    2014-06-10T23:59:59.000Z

    Theoretical studies of the nucleosynthesis origin of the heavy elements in our Solar System (S.S.) by the rapid neutron-capture process (r-process) still face the entwined uncertainties in the possible astrophysical scenarios and the nuclear-physics properties far from stability. In this paper we present results from the investigation of an r-process in the high-entropy wind (HEW) of core-collapse supernovae (here chosen as one of the possible scenarios for this nucleosynthesis process), using new nuclear-data input calculated in a consistent approach, for masses and $\\beta$-decay properties from the new finite-range droplet model FRDM(2012). The accuracy of the new mass model is 0.56 MeV with respect to {\\sc AME2003}, to which it was adjusted. We compare the new HEW r-process abundance pattern to the latest S.S. r-process residuals and to our earlier calculations with the nuclear-structure quantities based on FRDM(1992). Substantial overall and specific local improvements in the calculated pattern of the r-process between $A\\simeq 110$ and $^{209}$Bi, as well as remaining deficiencies are discussed in terms of the underlying spherical and deformed shell structure far from stability.

  20. Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation

    SciTech Connect (OSTI)

    J. Douglas Way; Paul M. Thoen

    2005-08-31T23:59:59.000Z

    This report summarizes progress made during the second year of research funding from DOE Grant DE-FG26-03NT41792 at the Colorado School of Mines. The period of performance was September 1, 2004 through August of 2005. We have reformulated our Pd plating process to minimize the presence of carbon contamination in our membranes. This has improved durability and increased permeability. We have developed techniques for plating the outside diameter of ceramic and metal substrate tubes. This configuration has numerous advantages including a 40% increase in specific surface area, the ability to assay the alloy composition non-destructively, the ability to potentially repair defects in the plated surface, and the ability to visually examine the plated surfaces. These improvements have allowed us to already meet the 2007 DOE Fossil Energy pure H{sub 2} flux target of 100 SCFH/ft{sup 2} for a hydrogen partial pressure difference of 100 psi with several Pd-Cu alloy membranes on ceramic microfilter supports. Our highest pure H{sub 2} flux on inexpensive, porous alumina support tubes at the DOE target conditions is 215 SCFH/ft{sup 2}. Progress toward meeting the other DOE Fossil Energy performance targets is also summarized. Additionally, we have adapted our membrane fabrication procedure to apply Pd and Pd alloy films to commercially available porous stainless steel substrates. Stable performance of Pd-Cu films on stainless steel substrates was demonstrated over a three week period at 400 C. Finally, we have fabricated and tested Pd-Au alloy membranes. These membranes also exceed both the 2007 and 2010 DOE pure H{sub 2} flux targets and exhibit ideal H{sub 2}/N{sub 2} selectivities of over 1000 at partial pressure difference of 100 psi.

  1. High-capacity nanostructured germanium-containing materials and lithium alloys thereof

    DOE Patents [OSTI]

    Graetz, Jason A. (Upton, NY); Fultz, Brent T. (Pasadena, CA); Ahn, Channing (Pasadena, CA); Yazami, Rachid (Los Angeles, CA)

    2010-08-24T23:59:59.000Z

    Electrodes comprising an alkali metal, for example, lithium, alloyed with nanostructured materials of formula Si.sub.zGe.sub.(z-1), where 0

  2. SUBTHRESHOLD DISPLACEMENT DAMAGE IN COPPER-ALUMINUM ALLOYS DURING ELECTRON IRRADIATION

    E-Print Network [OSTI]

    Drosd, R.

    2010-01-01T23:59:59.000Z

    DAMAGE IN COPPER-ALUMINUM ALLOYS DURING ELECTRON IRRADIATIONDAMAGE IN COPPER-ALUMINUM ALLOYS DURING ELECTRON IRRADIATIONby irradiating copper-aluminum alloys at high tempera­ tures

  3. On the Relation of KS Entropy and Permutation Entropy

    E-Print Network [OSTI]

    Karsten Keller; Anton M. Unakafov; Valentina A. Unakafova

    2014-07-24T23:59:59.000Z

    Since Bandt et al. have shown that the permutation entropy and the Kolmogorov-Sinai entropy coincide for piecewise monotone interval maps, the relationship of both entropies for time-discrete dynamical systems is of a certain interest. The aim of this paper is a discussion of this relationship on the basis of an ordinal characterization of the Kolmogorov-Sinai entropy recently given.

  4. PALLADIUM/COPPER ALLOY COMPOSITE MEMBRANES FOR HIGH TEMPERATURE HYDROGEN SEPARATION FROM COAL-DERIVED GAS STREAMS

    SciTech Connect (OSTI)

    J. Douglas Way

    2003-01-01T23:59:59.000Z

    For hydrogen from coal gasification to be used economically, processing approaches that produce a high purity gas must be developed. Palladium and its alloys, nickel, platinum and the metals in Groups 3 to 5 of the Periodic Table are all permeable to hydrogen. Hydrogen permeable metal membranes made of palladium and its alloys are the most widely studied due to their high hydrogen permeability, chemical compatibility with many hydrocarbon containing gas streams, and infinite hydrogen selectivity. Our Pd composite membranes have demonstrated stable operation at 450 C for over 70 days. Coal derived synthesis gas will contain up to 15000 ppm H{sub 2}S as well as CO, CO{sub 2}, N{sub 2} and other gases. Highly selectivity membranes are necessary to reduce the H{sub 2}S concentration to acceptable levels for solid oxide and other fuel cell systems. Pure Pd-membranes are poisoned by sulfur, and suffer from mechanical problems caused by thermal cycling and hydrogen embrittlement. Recent advances have shown that Pd-Cu composite membranes are not susceptible to the mechanical, embrittlement, and poisoning problems that have prevented widespread industrial use of Pd for high temperature H{sub 2} separation. These membranes consist of a thin ({le} 5 {micro}m) film of metal deposited on the inner surface of a porous metal or ceramic tube. With support from this DOE Grant, we have fabricated thin, high flux Pd-Cu alloy composite membranes using a sequential electroless plating approach. Thin, Pd{sub 60}Cu{sub 40} films exhibit a hydrogen flux more than ten times larger than commercial polymer membranes for H{sub 2} separation, resist poisoning by H{sub 2}S and other sulfur compounds typical of coal gas, and exceed the DOE Fossil Energy target hydrogen flux of 80 ml/cm{sup 2} {center_dot} min = 0.6 mol/m{sup 2} {center_dot} s for a feed pressure of 40 psig. Similar Pd-membranes have been operated at temperatures as high as 750 C. We have developed practical electroless plating procedures for fabrication of thin Pd-Cu composite membranes at any scale.

  5. Conditional entropy of ordinal patterns

    E-Print Network [OSTI]

    Anton M. Unakafov; Karsten Keller

    2014-07-21T23:59:59.000Z

    In this paper we investigate a quantity called conditional entropy of ordinal patterns, akin to the permutation entropy. The conditional entropy of ordinal patterns describes the average diversity of the ordinal patterns succeeding a given ordinal pattern. We observe that this quantity provides a good estimation of the Kolmogorov-Sinai entropy in many cases. In particular, the conditional entropy of ordinal patterns of a finite order coincides with the Kolmogorov-Sinai entropy for periodic dynamics and for Markov shifts over a binary alphabet. Finally, the conditional entropy of ordinal patterns is computationally simple and thus can be well applied to real-world data.

  6. Local entropy generation analysis

    SciTech Connect (OSTI)

    Drost, M.K.; White, M.D.

    1991-02-01T23:59:59.000Z

    Second law analysis techniques have been widely used to evaluate the sources of irreversibility in components and systems of components but the evaluation of local sources of irreversibility in thermal processes has received little attention. While analytical procedures for evaluating local entropy generation have been developed, applications have been limited to fluid flows with analytical solutions for the velocity and temperature fields. The analysis of local entropy generation can be used to evaluate more complicated flows by including entropy generation calculations in a computational fluid dynamics (CFD) code. The research documented in this report consists of incorporating local entropy generation calculations in an existing CFD code and then using the code to evaluate the distribution of thermodynamic losses in two applications: an impinging jet and a magnetic heat pump. 22 refs., 13 figs., 9 tabs.

  7. Maximum Entropy Correlated Equilibria

    E-Print Network [OSTI]

    Ortiz, Luis E.

    2006-03-20T23:59:59.000Z

    We study maximum entropy correlated equilibria in (multi-player)games and provide two gradient-based algorithms that are guaranteedto converge to such equilibria. Although we do not provideconvergence rates for these ...

  8. Structure Analysis of a Precipitate Phase in an Ni-Rich High Temperature NiTiHf Shape Memory Alloy

    SciTech Connect (OSTI)

    Yang, Fan; Coughlin, D. R.; Phillips, Patrick J.; Yang, L.; Devaraj, Arun; Kovarik, Libor; Noebe, Ronald D.; Mills, M. J.

    2013-03-22T23:59:59.000Z

    Thermal aging of the high temperature shape memory alloy 50.3Ni-29.7Ti-20Hf (at.%) introduces a novel precipitate phase, which plays an important role in improving shape memory properties. The precipitate phase was investigated by conventional electron diffraction, high resolution scanning transmission electron microscopy (STEM) and three dimensional atom probe tomography. An unrelaxed orthorhombic atomic structural model is proposed based on these observations. This model was subsequently relaxed by ab initio calculations. As a result of the relaxation, atom shuffle displacements occur, which in turn yields improved agreement with the STEM images. The relaxed structure, which is termed the “H-phase”, has also been verified to be thermodymanically stable at 0 K.

  9. Alloy materials

    DOE Patents [OSTI]

    Hans Thieme, Cornelis Leo (Westborough, MA); Thompson, Elliott D. (Coventry, RI); Fritzemeier, Leslie G. (Acton, MA); Cameron, Robert D. (Franklin, MA); Siegal, Edward J. (Malden, MA)

    2002-01-01T23:59:59.000Z

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  10. Universal crossovers between entanglement entropy and thermal entropy

    E-Print Network [OSTI]

    Swingle, Brian

    We postulate the existence of universal crossover functions connecting the universal parts of the entanglement entropy to the low-temperature thermal entropy in gapless quantum many-body systems. These scaling functions ...

  11. ORNL's Alumina-forming Austenitic Alloys Licensed to Carpenter...

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

    powder metal stainless steels and specialty alloys including high temperature (iron-nickel-cobalt base), stainless, superior corrosion resistant, controlled expansion alloys,...

  12. Entropy and quantum gravity

    E-Print Network [OSTI]

    Kay, Bernard S

    2015-01-01T23:59:59.000Z

    We give an account of the matter-gravity entanglement hypothesis which, unlike the standard approach to entropy based on coarse-graining, offers a definition for the entropy of a closed system as a real and objective quantity. We explain how this new approach offers an explanation for the Second Law of Thermodynamics in general and a non-paradoxical understanding of information loss during black hole formation and evaporation in particular. We also very briefly review some recent related work on the nature of equilibrium states involving quantum black holes and point out how it promises to resolve some puzzling issues in the current version of the string theory approach to black hole entropy.

  13. On entropy production

    SciTech Connect (OSTI)

    Stenholm, Stig [Physics Department, Royal Institute of Technology, KTH, ALBANOVA, Roslagstullsbacken 21, SE-10691 Stockholm (Sweden); Laboratory of Computational Engineering, HUT, Espoo (Finland)], E-mail: stenholm@atom.kth.se

    2008-11-15T23:59:59.000Z

    We investigate the case of a dynamical system when irreversible time evolution is generated by a nonHermitian superoperator on the states of the system. We introduce a generalized scalar product which can be used to construct a monotonically changing functional of the state, a generalized entropy. This will depend on the level of system dynamics described by the evolution equation. In this paper we consider the special case when the irreversibility derives from imbedding the system of interest into a thermal reservoir. The ensuing time evolution is shown to be compatible both with equilibrium thermodynamics and the entropy production near the final steady state. In particular, Prigogine's principle of minimum entropy production is discussed. Also the limit of zero temperature is considered. We present comments on earlier treatments.

  14. Very high strain-rate response of a NiTi shape-memory alloy Sia Nemat-Nasser *, Jeom-Yong Choi, Wei-Guo Guo, Jon B. Isaacs

    E-Print Network [OSTI]

    Nemat-Nasser, Sia

    Very high strain-rate response of a NiTi shape-memory alloy Sia Nemat-Nasser *, Jeom-Yong Choi, Wei Received 1 January 2004 Abstract The compressive response of a NiTi shape-memory alloy is investigated for the stress-induced martensite formation equals the yield stress of the austenite phase. Therefore, the shape-memory

  15. Effects of the interplay between atomic and magnetic order on the properties of metamagnetic Ni-Co-Mn-Ga shape memory alloys

    SciTech Connect (OSTI)

    Seguí, C., E-mail: concepcio.segui@uib.es [Departament de Física, Universitat de les Illes Balears, Campus universitari. Cra. de Valldemossa km 7.5, 07122 Palma de Mallorca (Spain)

    2014-03-21T23:59:59.000Z

    Ni-Co-Mn-Ga ferromagnetic shape memory alloys show metamagnetic behavior for a range of Co contents. The temperatures of the structural and magnetic transitions depend strongly on composition and atomic order degree, in such a way that combined composition and thermal treatment allows obtaining martensitic transformation between any magnetic state of austenite and martensite. This work presents a detailed analysis of the effect of atomic order on Ni-Co-Mn-Ga alloys through the evolution of structural and magnetic transitions after quench from high temperatures and during post-quest ageing. It is found that the way in which the atomic order affects the martensitic transformation temperatures and entropy depends on the magnetic order of austenite and martensite. The results can be explained assuming that improvement of atomic order decreases the free energy of the structural phases according to their magnetic order. However, it is assumed in this work that changes in the slope—that is, the entropy—of the Gibbs free energy curves are also decisive to the stability of the two-phase system. The experimental transformation entropy values have been compared with a phenomenological model, based on a Bragg–Williams approximation, accounting for the magnetic contribution. The excellent agreement obtained corroborates the magnetic origin of changes in transformation entropy brought about by atomic ordering.

  16. Contribution of the vibrational free energy to phase stability in substitutional alloys: Methods and trends

    E-Print Network [OSTI]

    Ceder, Gerbrand

    -principles calculations of alloy phase diagrams a powerful tool in materials science.1,2 Pre- cise control of external entropy of a material and to evaluate its phase diagram. Although first-principles calcula- tions based phase transformations can be com- parable in magnitude to the change in the configurational entropy

  17. Renyi Entropy and Free Energy

    E-Print Network [OSTI]

    John C. Baez

    2011-06-06T23:59:59.000Z

    The Renyi entropy is a generalization of the usual concept of entropy which depends on a parameter q. In fact, Renyi entropy is closely related to free energy. Suppose we start with a system in thermal equilibrium and then suddenly divide the temperature by q. Then the maximum amount of work the system can do as it moves to equilibrium at the new temperature, divided by the change in temperature, equals the system's Renyi entropy in its original state. This result applies to both classical and quantum systems. Mathematically, we can express this result as follows: the Renyi entropy of a system in thermal equilibrium is minus the "1/q-derivative" of its free energy with respect to temperature. This shows that Renyi entropy is a q-deformation of the usual concept of entropy.

  18. Vehicle Technologies Office Merit Review 2015: High Strength, Dissimilar Alloy Aluminum Tailor-Welded Blanks

    Broader source: Energy.gov [DOE]

    Presentation given by Pacific Northwest National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  19. Vehicle Technologies Office Merit Review 2014: High Temperature Aluminum Alloys (Agreement ID:24034) Project ID:18518

    Broader source: Energy.gov [DOE]

    Presentation given by Pacific Northwest National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  20. Vehicle Technologies Office Merit Review 2014: High Speed Joining of Dissimilar Alloy Aluminum Tailor Welded Blanks

    Broader source: Energy.gov [DOE]

    Presentation given by Pacific Northwest National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  1. PALLADIUM/COPPER ALLOY COMPOSITE MEMBRANES FOR HIGH TEMPERATURE HYDROGEN SEPARATION FROM COAL-DERIVED GAS STREAMS

    SciTech Connect (OSTI)

    J. Douglas Way; Robert L. McCormick

    2001-06-01T23:59:59.000Z

    Recent advances have shown that Pd-Cu composite membranes are not susceptible to the mechanical, embrittlement, and poisoning problems that have prevented widespread industrial use of Pd for high temperature H{sub 2} separation. These membranes consist of a thin ({approx}10 {micro}m) film of metal deposited on the inner surface of a porous metal or ceramic tube. Based on preliminary results, thin Pd{sub 60}Cu{sub 40} films are expected to exhibit hydrogen flux up to ten times larger than commercial polymer membranes for H{sub 2} separation, and resist poisoning by H{sub 2}S and other sulfur compounds typical of coal gas. Similar Pd-membranes have been operated at temperatures as high as 750 C. The overall objective of the proposed project is to demonstrate the feasibility of using sequential electroless plating to fabricate Pd{sub 60}Cu{sub 40} alloy membranes on porous supports for H{sub 2} separation. These following advantages of these membranes for processing of coal-derived gas will be demonstrated: High H{sub 2} flux; Sulfur tolerant, even at very high total sulfur levels (1000 ppm); Operation at temperatures well above 500 C; and Resistance to embrittlement and degradation by thermal cycling. The proposed research plan is designed to providing a fundamental understanding of: Factors important in membrane fabrication; Optimization of membrane structure and composition; Effect of temperature, pressure, and gas composition on H{sub 2} flux and membrane selectivity; and How this membrane technology can be integrated in coal gasification-fuel cell systems.

  2. Maximum entropy method and oscillations in the diffraction cone

    E-Print Network [OSTI]

    O. Dumbrajs; J. Kontros; A. Lengyel

    2000-07-15T23:59:59.000Z

    The maximum entropy method has been applied to investigate the oscillating structure in the pbarp- and pp-elastic scattering differential cross-section at high energy and small momentum transfer. Oscillations satisfying quite realistic reliability criteria have been found.

  3. Amorphous metal alloy and composite

    DOE Patents [OSTI]

    Wang, Rong (Richland, WA); Merz, Martin D. (Richland, WA)

    1985-01-01T23:59:59.000Z

    Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

  4. Synthesis of high T.sub.C superconducting coatings and patterns by melt writing and oxidation of metallic precursor alloys

    DOE Patents [OSTI]

    Gao, Wei (Somerville, MA); Vander Sande, John B. (Newbury, MA)

    1998-01-01T23:59:59.000Z

    A method is provided for fabrication of superconducting oxides and superconducting oxide composites and for joining superconductors to other materials. A coating of a molten alloy containing the metallic elements of the oxide is applied to a substrate surface and oxidized to form the superconducting oxide. A material can be contacted to the molten alloy which is subsequently oxidized joining the material to the resulting superconducting oxide coating. Substrates of varied composition and shape can be coated or joined by this method.

  5. Entropy Meters and the Entropy of Non-extensive Systems

    E-Print Network [OSTI]

    Elliott H. Lieb; Jakob Yngvason

    2014-03-30T23:59:59.000Z

    In our derivation of the second law of thermodynamics from the relation of adiabatic accessibility of equilibrium states we stressed the importance of being able to scale a system's size without changing its intrinsic properties. This leaves open the question of defining the entropy of macroscopic, but unscalable systems, such as gravitating bodies or systems where surface effects are important. We show here how the problem can be overcome, in principle, with the aid of an `entropy meter'. An entropy meter can also be used to determine entropy functions for non-equilibrium states and mesoscopic systems.

  6. D.D. Luong et al. / Journal of Alloys and Compounds 550 (2013) 412422 412 Development of high performance lightweight aluminum alloy/SiC hollow sphere syntactic foams and compressive

    E-Print Network [OSTI]

    Gupta, Nikhil

    2013-01-01T23:59:59.000Z

    performance lightweight aluminum alloy/SiC hollow sphere syntactic foams and compressive characterization and Materials Research Directorate, Aberdeen Proving Ground, MD 21005 USA ABSTRACT Aluminum alloy A356 filled matrix composite (AMC) systems. Aluminum alloys and AMCs have been used to replace steel in automotive

  7. High Accuracy U-235 Enrichment Verification Station for Low Enriched Uranium Alloys

    SciTech Connect (OSTI)

    Lillard, C. R.; Hayward, J. P.; Williamson, M. R.

    2012-06-07T23:59:59.000Z

    The Y-12 National Security Complex is playing a role in the U.S. High Performance Research Reactor (USHPRR) Conversion program sponsored by the U.S. National Nuclear Security Administration's Office of Global Threat Reduction. The USHPRR program has a goal of converting remaining U.S. reactors that continue to use highly enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. The USHPRR program is currently developing a LEU Uranium-Molybdenum (U-Mo) monolithic fuel for use in the U.S. high performance research reactors.Y-12 is supporting both the fuel development and fuel fabrication efforts by fabricating low enriched U-Mo foils from its own source material for irradiation experiments and for optimizing the fabrication process in support of scaling up the process to a commercial production scale. Once the new fuel is qualified, Y-12 will produce and ship U-Mo coupons with verified 19.75% +0.2% - 0.3% U-235 enrichment to be fabricated into fuel elements for the USHPRRs. Considering this small enrichment tolerance and the transition into HEU being set strictly at 20% U-235, a characterization system with a measurement uncertainty of less than or equal to 0.1% in enrichment is desired to support customer requirements and minimize production costs. Typical uncertainty for most available characterization systems today is approximately 1-5%; therefore, a specialized system must be developed which results in a reduced measurement uncertainty. A potential system using a High-Purity Germanium (HPGe) detector has been procured, and tests have been conducted to verify its capabilities with regards to the requirements. Using four U-Mo enrichment standards fabricated with complete isotopic and chemical characterization, infinite thickness and peak-ratio enrichment measurement methods have been considered for use. As a result of inhomogeneity within the U-Mo samples, FRAM, an isotopic analysis software, has been selected for initial testing. A systematic approach towards observing effects on FRAM's enrichment analysis has been conducted with regards to count and dead time.

  8. High Quality, Dense Thin Films Using Metal/Metal Alloy Additives - Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cn SunnybankD.jpgHanfordDepartmentInnovationHigh

  9. Investigation of a high spatial resolution method based on polar coordinate maximum entropy method for analyzing electron density fluctuation data measured by laser phase contrast

    SciTech Connect (OSTI)

    Matsuo, K. [Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Iguchi, H.; Okamura, S.; Matsuoka, K. [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2012-01-15T23:59:59.000Z

    Laser phase contrast is a powerful diagnostic method to determine the spatial distribution of electron density fluctuations in magnetically confined plasmas, although its applicability depends on magnetic field configurations. The spatial resolution of fluctuations is linked with the resolution of the propagation direction that is derived from the two-dimensional spectral analysis of the wavenumber for the fluctuations. The method was applied to fluctuation measurements in a compact helical system. In order to improve the resolution of the propagation direction with a relatively small number of data points, the maximum entropy method with polar coordinates was employed. A spatial resolution of the order of 1 cm was obtained, which is satisfactory in a plasma with a 20 cm minor radius.

  10. SEM Characterization of the High Burn-up Microstructure of U-7Mo Alloy

    SciTech Connect (OSTI)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Jian Gan; Brandon Miller; Adam Robinson; Pavel Medvedev; James Madden; Dan Wachs; M. Teague

    2014-04-01T23:59:59.000Z

    During irradiation, the microstructure of U-7Mo evolves until at a fission density near 5x1021 f/cm3 a high-burnup microstructure exists that is very different than what was observed at lower fission densities. This microstructure is dominated by randomly distributed, relatively large, homogeneous fission gas bubbles. The bubble superlattice has collapsed in many microstructural regions, and the fuel grain sizes, in many areas, become sub-micron in diameter with both amorphous fuel and crystalline fuel present. Solid fission product precipitates can be found inside the fission gas bubbles. To generate more information about the characteristics of the high-fission density microstructure, three samples irradiated in the RERTR-7 experiment have been characterized using a scanning electron microscope equipped with a focused ion beam. The FIB was used to generate samples for SEM imaging and to perform 3D reconstruction of the microstructure, which can be used to look for evidence of possible fission gas bubble interlinkage.

  11. Deformation Behavior of Laser Welds in High Temperature Oxidation Resistant Fe-Cr-Al Alloys for Fuel Cladding Applications

    SciTech Connect (OSTI)

    Field, Kevin G [ORNL; Gussev, Maxim N [ORNL; Yamamoto, Yukinori [ORNL; Snead, Lance Lewis [ORNL

    2014-01-01T23:59:59.000Z

    Ferritic-structured Fe-Cr-Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability of three model alloys in a range of Fe-(13-17.5)Cr-(3-4.4)Al in weight percent with a minor addition of yttrium using laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds has been carried out to determine the performance of welds as a function of alloy composition. Laser welding resulted in a defect free weld devoid of cracking or inclusions for all alloys studied. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. No significant correlation was found between the deformation behavior/mechanical performance of welds and the level of Cr or Al in the alloy ranges studied.

  12. Estimating a mixed strategy employing maximum entropy

    E-Print Network [OSTI]

    Golan, Amos; Karp, Larry; Perloff, Jeffrey M.

    1996-01-01T23:59:59.000Z

    MIXED STRATEGY EMPLOYING MAXIMUM ENTROPY by Amos Golan LarryMixed Strategy Employing Maximum Entropy Amos Golan Larry S.Abstract Generalized maximum entropy may be used to estimate

  13. High Temperature Oxidation Behavior of gamma-Ni+gamma'-Ni3Al Alloys and Coatings Modified with Pt and Reactive Elements

    SciTech Connect (OSTI)

    Nan Mu

    2007-12-01T23:59:59.000Z

    Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000 C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455 C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain {beta}-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al{sub 2}O{sub 3} scale at elevated temperatures. The drawbacks to the currently-used {beta}-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt + Hf-modified {gamma}-Ni + {gamma}-Ni{sub 3}Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase {gamma}-Ni and {gamma}{prime}-Ni{sub 3}Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al{sub 2}O{sub 3} formation by suppressing the NiO growth on both {gamma}-Ni and {gamma}{prime}Ni{sub 3}Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at lower temperatures ({approx}970 C) in the very early stage of oxidation. It was also inferred that Pt enhances the diffusive flux of aluminum from the substrate to the scale/alloy interface. Relatively low levels of hafnium addition to Pt-free {gamma}{prime}-Ni{sub 3}Al increased the extent of external NiO formation due to non-protective HfO{sub 2} formation. Accordingly, this effect intensified with increasing Hf content from 0.2 to 0.5 at.%.

  14. Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

    SciTech Connect (OSTI)

    Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen

    2008-09-30T23:59:59.000Z

    The effect of H{sub 2}S poisoning on Pd, Pd/Cu, and Pd/Au alloy composite membranes prepared by the electroless deposition method on porous Inconel supports was investigated to provide a fundamental understanding of the durability and preparation of sulfur tolerant membranes. X-ray photoelectron spectroscopy (XPS) studies showed that the exposure of pure Pd to 50 ppm H{sub 2}S/H{sub 2} mixtures caused bulk sulfide formation at lower temperatures and surface sulfide formation at higher temperatures. Lower temperatures, longer exposure times, and higher H{sub 2}S concentrations resulted in a higher degree of sulfidation. In a Pd membrane, the bulk sulfide formation caused a drastic irrecoverable H{sub 2} permeance decline and an irreparable loss in selectivity. Pd/Cu and Pd/Au alloy membranes exhibited permeance declines due to surface sulfide formation upon exposure to 50 ppm H{sub 2}S/H{sub 2} gas mixtures. However in contrast to the pure Pd membrane, the permeances of the Pd/Cu and Pd/Au alloy membranes were mostly recovered in pure H{sub 2} and the selectivity of the Pd alloy layers remained essentially intact throughout the characterization in H{sub 2}, He and H{sub 2}S/H{sub 2} mixtures which lasted several thousand hours. The amount of irreversible sulfur poisoning decreased with increasing temperature due to the exothermicity of H{sub 2}S adsorption. Longer exposure times increased the amount of irreversible poisoning of the Pd/Cu membrane but not the Pd/Au membrane. Pd/Au coupon studies of the galvanic displacement method showed that higher Au{sup 3+} concentrations, lower pH values, higher bath temperatures and stirring the bath at a rate of 200 rpm yielded faster displacement rates, more uniform depositions, and a higher Au content within the layers. While 400 C was found to be sufficient to form a Pd/Au alloy on the surface, high temperature X-ray diffraction (HTXRD) studies showed that even after annealing between 500-600 C, the Pd/Cu alloys could have part or all of the surface in the less sulfur resistant {beta} phase.

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

    SciTech Connect (OSTI)

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

    2014-10-15T23:59:59.000Z

    High-resolution microscopy of a high-purity Ni-5Cr alloy exposed to 360°C hydrogenated water reveals intergranular selective oxidation of Cr accompanied by local Cr depletion and diffusion-induced grain boundary migration (DIGM). The corrosion-product oxide consists of a porous, interconnected network of Cr2O3 platelets with no further O ingress into the metal ahead. Extensive grain boundary depletion of Cr (to <0.05at.%) is observed typically 20–100 nm wide as a result of DIGM and reaching depths of many micrometers beyond the oxidation front.

  16. Synthesis of high {Tc} superconducting coatings and patterns by melt writing and oxidation of metallic precursor alloys

    DOE Patents [OSTI]

    Gao, W.; Vander Sande, J.B.

    1998-07-28T23:59:59.000Z

    A method is provided for fabrication of superconducting oxides and superconducting oxide composites and for joining superconductors to other materials. A coating of a molten alloy containing the metallic elements of the oxide is applied to a substrate surface and oxidized to form the superconducting oxide. A material can be contacted to the molten alloy which is subsequently oxidized joining the material to the resulting superconducting oxide coating. Substrates of varied composition and shape can be coated or joined by this method. 5 figs.

  17. Saturating the holographic entropy bound

    SciTech Connect (OSTI)

    Bousso, Raphael [Center for Theoretical Physics, Department of Physics University of California, Berkeley, California 94720-7300 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720-8162 (United States); Institute for the Physics and Mathematics of the Universe, University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa City, Chiba 277-8568 (Japan); Freivogel, Ben; Leichenauer, Stefan [Center for Theoretical Physics, Department of Physics University of California, Berkeley, California 94720-7300 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720-8162 (United States)

    2010-10-15T23:59:59.000Z

    The covariant entropy bound states that the entropy, S, of matter on a light sheet cannot exceed a quarter of its initial area, A, in Planck units. The gravitational entropy of black holes saturates this inequality. The entropy of matter systems, however, falls short of saturating the bound in known examples. This puzzling gap has led to speculation that a much stronger bound, S < or approx. A{sup 3/4}, may hold true. In this note, we exhibit light sheets whose entropy exceeds A{sup 3/4} by arbitrarily large factors. In open Friedmann-Robertson-Walker universes, such light sheets contain the entropy visible in the sky; in the limit of early curvature domination, the covariant bound can be saturated but not violated. As a corollary, we find that the maximum observable matter and radiation entropy in universes with positive (negative) cosmological constant is of order {Lambda}{sup -1} ({Lambda}{sup -2}), and not |{Lambda}|{sup -3/4} as had hitherto been believed. Our results strengthen the evidence for the covariant entropy bound, while showing that the stronger bound S < or approx. A{sup 3/4} is not universally valid. We conjecture that the stronger bound does hold for static, weakly gravitating systems.

  18. Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf) 

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12T23:59:59.000Z

    by other means. We have used Equal Channel Angular Extrusion (ECAE), hot rolling and marforming to strengthen the 49.8Ni-42.2Ti-8Hf (in at. %) material and to introduce desired texture to overcome these problems in NiTiHf alloys. ECAE offers the advantage...

  19. DOI: 10.1002/chem.201200292 Synthesis of NiRu Alloy Nanoparticles and Their High Catalytic Activity in

    E-Print Network [OSTI]

    molecular candidates for hydrogen storage[8­11] be- cause of its outstanding physicochemical properties interactions between B and N atoms[8] ), good stability in neutral and in alkaline aqueous solutions, safe. The alloy NPs were ob- tained by wet-chemistry method using a rapid lithium triethylborohydride re- duction

  20. Computer Simulation and Experimental Validation on the Oxidation and Sulfate Corrosion Resistance of Novel Chromium Based High Temperature Alloys

    SciTech Connect (OSTI)

    Yang, Shizhong

    2013-02-28T23:59:59.000Z

    This report summarizes our recent works of ab initio molecular dynamics inter-atomic potentials development on dilute rare earth element yttrium (Y) etc. doped chromium (Cr) alloy systems, its applications in oxidation and corrosion resistance simulation, and experiment validation on the candidate systems. The simulation methods, experimental validation techniques, achievements already reached, students training, and future improvement are briefly introduced.

  1. Entropy bound for the photon gas in noncommutative spacetime

    E-Print Network [OSTI]

    Nozari, K; Kamali, A Damavandi; Vakili, B

    2015-01-01T23:59:59.000Z

    Motivated by the doubly special relativity theories and noncommutative spacetime structures, thermodynamical properties of the photon gas in a phase space with compact spatial momentum space is studied. At the high temperature limit, the upper bounds for the internal energy and entropy are obtained which are determined by the size of the compact spatial momentum space. The maximum internal energy turns out to be of the order of the Planck energy and the entropy bound is then determined by the factor $\\big(V/l_{_{\\rm Pl}}^3\\big)$ through the relevant identification of the size of the momentum space with Planck scale. The entropy bound is very similar to the case of Bekenstein-Hawking entropy of black holes and suggests that thermodynamics of black holes may be deduced from a saturated state in the framework of a full quantum gravitational statistical mechanics.

  2. Decoherence and entropy of primordial fluctuations II. The entropy budget

    E-Print Network [OSTI]

    David Campo; Renaud Parentani

    2008-05-05T23:59:59.000Z

    We calculate the entropy of adiabatic perturbations associated with a truncation of the hierarchy of Green functions at the first non trivial level, i.e. in a self-consistent Gaussian approximation. We give the equation governing the entropy growth and discuss its phenomenology. It is parameterized by two model-dependent kernels. We then examine two particular inflationary models, one with isocurvature perturbations, the other with corrections due to loops of matter fields. In the first model the entropy grows rapidely, while in the second the state remains pure (at one loop).

  3. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.

    2005-10-01T23:59:59.000Z

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  4. Microstructural Evolution of Alloy 718 at High Helium and Hydrogen Generation Rates during Irradiation with 600-800 MeV protons

    SciTech Connect (OSTI)

    Sencer, Bulent H. (PNNL); Bond, G M. (PNNL); Garner, F.A. (Pacific Northwest National Laboratory); Hamilton, M L. (PNNL); Oliver, Brian M. (BATTELLE (PACIFIC NW LAB)); Thomas, L E. (PNNL); Maloy, S A. (Los Alamos National Laboratory); Sommer, Walter F. (LOS ALAMOS NATL LAB); James, M R. (Los Alamos National Laboratory); Ferguson, P D. (Los Alamos National Laboratory)

    2000-12-01T23:59:59.000Z

    When precipitation hardened Alloy 718 is irradiated with high-energy protons (600?800 MeV) and spallation neutrons at temperatures below > 60 C, it quickly hardens and loses almost all uniform elongation. It later softens somewhat at higher exposures but does not regain any elongation. This behavior is explained in terms of the evolution of Frank loop formation, disordering and eventual dissolution of the?? and?? strengthening phases, and the steady accumulation of very large levels of helium and hydrogen. These gases must be dispersed on a very fine scale in the matrix since no cavities could be found.

  5. Entropy distance: New quantum phenomena

    SciTech Connect (OSTI)

    Weis, Stephan [Max Planck Institute for Mathematics in the Sciences, Inselstr. 22, D-04103 Leipzig (Germany); Knauf, Andreas [Department of Mathematics, Friedrich-Alexander-University Erlangen-Nuremberg, Cauerstr. 11, D-91058 Erlangen (Germany)

    2012-10-15T23:59:59.000Z

    We study a curve of Gibbsian families of complex 3 Multiplication-Sign 3-matrices and point out new features, absent in commutative finite-dimensional algebras: a discontinuous maximum-entropy inference, a discontinuous entropy distance, and non-exposed faces of the mean value set. We analyze these problems from various aspects including convex geometry, topology, and information geometry. This research is motivated by a theory of infomax principles, where we contribute by computing first order optimality conditions of the entropy distance.

  6. Entropy balance in holographic superconductors

    E-Print Network [OSTI]

    Sean A. Hartnoll; Razieh Pourhasan

    2012-05-07T23:59:59.000Z

    In systems undergoing second order phase transitions, the temperature integral of the specific heat over temperature from zero to the critical temperature is the same in both the normal and ordered phases. This entropy balance relates the critical temperature to the distribution of degrees of freedom in the normal and ordered states. Quantum criticality and fractionalization can imply an increased number of low energy degrees of freedom in both the normal and ordered states. We explore the role of entropy balance in holographic models of superconductivity, focussing on the interplay between quantum criticality and superconductivity. We consider models with and without a ground state entropy density in the normal phase; the latter models are a new class of holographic superconductors. We explain how a normal phase entropy density manifests itself in the stable superconducting phase.

  7. Entropy bounds for uncollapsed matter

    E-Print Network [OSTI]

    Gabriel Abreu; Matt Visser

    2010-11-19T23:59:59.000Z

    In any static spacetime the quasilocal Tolman mass contained within a volume can be reduced to a Gauss-like surface integral involving the flux of a suitably defined generalized surface gravity. By introducing some basic thermodynamics, and invoking the Unruh effect, one can then develop elementary bounds on the quasilocal entropy that are very similar in spirit to the holographic bound, and closely related to entanglement entropy.

  8. Alloy nanoparticle synthesis using ionizing radiation

    DOE Patents [OSTI]

    Nenoff, Tina M. (Sandia Park, NM); Powers, Dana A. (Albuquerque, NM); Zhang, Zhenyuan (Durham, NC)

    2011-08-16T23:59:59.000Z

    A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

  9. Passive Corrosion Behavior of Alloy 22

    SciTech Connect (OSTI)

    R.B. Rebak; J.H. Payer

    2006-01-20T23:59:59.000Z

    Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  10. Microstructure of TiB{sub 2}/carbon steel surface-alloyed materials fabricated by high-energy electron beam irradiation

    SciTech Connect (OSTI)

    Euh, K. Lee, S.; Shin, K.

    1999-12-01T23:59:59.000Z

    The processing and the microstructural analysis of TiB{sub 2}/carbon steel surface-alloyed materials using the irradiation of a high-energy electron beam were investigated in this study. The mixtures of TiB{sub 2} powders and flux were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these mixtures using an electron beam accelerator. The microstructure of the irradiated surface layer was composed of a melted region, an interfacial region, a coarse-grained heat-affected zone (HAZ), and a fine-grained HAZ. A few residual micropores were found in the melted region of the specimen processed without flux because of irregular thermal transfer, but their number was decreased in the specimens processed with a considerable amount of flux. As a result of irradiation, the Ti content was homogeneously maintained throughout the melted region, whose hardness was greatly improved. This was associated with the microstructural modification including the segregation of Ti and B along solidification cell boundaries and the formation of fine Ti(C, N) particles. The proper flux mix ratio was 15 to 30% to obtain excellent surface alloying and a homogeneous microstructure.

  11. CVD of refractory amorphous metal alloys

    SciTech Connect (OSTI)

    Tenhover, M. [The Carborundum Co., Niagara Falls, NY (United States). Technology Div.

    1995-08-01T23:59:59.000Z

    In this work, a novel process is described for the fabrication of multi-metallic amorphous metal alloy coatings using a chemical vapor deposition (CVD) technique. Of special interest in this work are amorphous metal alloys containing Mo and/or Cr which have high crystallization temperatures and readily available low decomposition temperature metal-bearing precursors. The conditions for amorphous alloy formation via CVD are described as well as the chemical properties of these materials. High temperature, aqueous corrosion tests have shown these materials (especially those containing Cr) are among the most corrosion resistant metal alloys known.

  12. An improved model for the transit entropy of monatomic liquids

    SciTech Connect (OSTI)

    Wallace, Duane C [Los Alamos National Laboratory; Chisolm, Eric D [Los Alamos National Laboratory; Bock, Nicolas [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    In the original formulation of V-T theory for monatomic liquid dynamics, the transit contribution to entropy was taken to be a universal constant, calibrated to the constant-volume entropy of melting. This model suffers two deficiencies: (a) it does not account for experimental entropy differences of {+-}2% among elemental liquids, and (b) it implies a value of zero for the transit contribution to internal energy. The purpose of this paper is to correct these deficiencies. To this end, the V-T equation for entropy is fitted to an overall accuracy of {+-}0.1% to the available experimental high temperature entropy data for elemental liquids. The theory contains two nuclear motion contributions: (a) the dominant vibrational contribution S{sub vib}(T/{theta}{sub 0}), where T is temperature and {theta}{sub 0} is the vibrational characteristic temperature, and (b) the transit contribution S{sub tr}(T/{theta}{sub tr}), where {theta}{sub tr} is a scaling temperature for each liquid. The appearance of a common functional form of S{sub tr} for all the liquids studied is a property of the experimental data, when analyzed via the V-T formula. The resulting S{sub tr} implies the correct transit contribution to internal energy. The theoretical entropy of melting is derived, in a single formula applying to normal and anomalous melting alike. An ab initio calculation of {theta}{sub 0}, based on density functional theory, is reported for liquid Na and Cu. Comparison of these calculations with the above analysis of experimental entropy data provides verification of V-T theory. In view of the present results, techniques currently being applied in ab initio simulations of liquid properties can be employed to advantage in the further testing and development of V-T theory.

  13. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN)

    1998-01-01T23:59:59.000Z

    Alloys for use in structural applications based upon NiAl to which are added selected elements to enhance room temperature ductility and high temperature strength. Specifically, small additions of molybdenum produce a beneficial alloy, while further additions of boron, carbon, iron, niobium, tantalum, zirconium and hafnium further improve performance of alloys at both room temperature and high temperatures. A preferred alloy system composition is Ni--(49.1.+-.0.8%)Al--(1.0.+-.0.8%)Mo--(0.7.+-.0.5%)Nb/Ta/Zr/Hf--(nearly zero to 0.03%)B/C, where the % is at. % in each of the concentrations. All alloys demonstrated good oxidation resistance at the elevated temperatures. The alloys can be fabricated into components using conventional techniques.

  14. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, C.T.

    1998-03-10T23:59:59.000Z

    Alloys are disclosed for use in structural applications based upon NiAl to which are added selected elements to enhance room temperature ductility and high temperature strength. Specifically, small additions of molybdenum produce a beneficial alloy, while further additions of boron, carbon, iron, niobium, tantalum, zirconium and hafnium further improve performance of alloys at both room temperature and high temperatures. A preferred alloy system composition is Ni--(49.1{+-}0.8%)Al--(1.0{+-}0.8%)Mo--(0.7 + 0.5%)Nb/Ta/Zr/Hf--(nearly zero to 0.03%)B/C, where the % is at. % in each of the concentrations. All alloys demonstrated good oxidation resistance at the elevated temperatures. The alloys can be fabricated into components using conventional techniques. 4 figs.

  15. Quantum geometry and gravitational entropy

    SciTech Connect (OSTI)

    Simon, Joan; Balasubramanian, Vijay; Czech, Bart Iomiej; Larjo, Klaus; Marolf, Donald; Simon, Joan

    2007-05-29T23:59:59.000Z

    Most quantum states have wavefunctions that are widely spread over the accessible Hilbert space and hence do not have a good description in terms of a single classical geometry. In order to understand when geometric descriptions are possible, we exploit the AdS/CFT correspondence in the half-BPS sector of asymptotically AdS_5 x S5 universes. In this sector we devise a"coarse-grained metric operator" whose eigenstates are well described by a single spacetime topology and geometry. We show that such half-BPS universes have a non-vanishing entropy if and only if the metric is singular, and that the entropy arises from coarse-graining the geometry. Finally, we use our entropy formula to find the most entropic spacetimes with fixed asymptotic moments beyond the global charges.

  16. Assessment of susceptibility to chloride stress corrosion cracking of highly alloyed stainless steels. Part 2: A new immersion test method

    SciTech Connect (OSTI)

    Drugli, J.M.; Steinsmo, U. [SINTEF Materials Technology, Trondheim (Norway)

    1997-12-01T23:59:59.000Z

    A new method for assessment of susceptibility to chloride stress corrosion cracking under severe evaporative conditions has been developed. The basic idea is to test under submerged conditions simulating the electrolyte composition and concentration of sea water during evaporation. Two duplex and one austenitic stainless steel were tested loaded to the yield point at the test temperature. Time to failure, potential and temperature were recorded continuously. The results showed cracking of the austenitic material UNS S31254 at 110 C by long term testing. For the duplex stainless steels UNS S31803 and UNS S32750 cracking was observed at 100 C. The time to cracking was longest for the last mentioned and highest alloyed duplex material.

  17. Entanglement Entropy and the Fermi Surface

    E-Print Network [OSTI]

    Swingle, Brian Gordon

    Free fermions with a finite Fermi surface are known to exhibit an anomalously large entanglement entropy. The leading contribution to the entanglement entropy of a region of linear size L in d spatial dimensions is ...

  18. Comparison of Maximum Entropy and Higher-Order Entropy Estimators Amos Golan* and Jeffrey M. Perloff**

    E-Print Network [OSTI]

    Perloff, Jeffrey M.

    Comparison of Maximum Entropy and Higher-Order Entropy Estimators Amos Golan* and Jeffrey M. Perloff** ABSTRACT We show that the generalized maximum entropy (GME) is the only estimation method- classes of estimators may outperform the GME estimation rule. Keywords: generalized entropy, maximum

  19. In situ atomic force microscope study of high-temperature untwinning surface relief in Mn-Fe-Cu antiferromagnetic shape memory alloy

    SciTech Connect (OSTI)

    Wang, L.; Cui, Y. G.; Wan, J. F.; Rong, Y. H.; Zhang, J. H.; Jin, X.; Cai, M. M. [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)] [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2013-05-06T23:59:59.000Z

    The N-type untwinning surface relief associated with the fcc {r_reversible} fct martensitic transformation (MT) was observed in the Mn{sub 81.5}Fe{sub 14.0}Cu{sub 4.5} antiferromagnetic high-temperature shape memory alloy (SMA) by in situ atomic force microscopy. The measured untwinning relief angles ({theta}{sub {alpha}} Double-Vertical-Line {theta}{sub {beta}}) at the ridge and at the valley were different, and both angles were less than the conventional values. The surface relief exhibited good reversibility during heating and cooling because of the crystallographic reversibility of thermal-elastic SMAs. Untwinning shear was proposed as the main mechanism of the N-type surface relief. The order of the reverse MT was discussed based on the experimental measurements.

  20. Phonon densities of states of face-centered-cubic Ni-Fe alloys

    SciTech Connect (OSTI)

    Lucas, Matthew [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Mauger, L [California Institute of Technology, W. M. Keck Laboratory, Pasadena] [California Institute of Technology, W. M. Keck Laboratory, Pasadena; Munoz, Jorge A. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Halevy, I [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Horwath, J [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Semiatin, S L [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Leontsev, S. O. [University of Kentucky, Lexington] [University of Kentucky, Lexington; Stone, Matthew B [ORNL] [ORNL; Abernathy, Douglas L [ORNL] [ORNL; Xiao, Yuming [Carnegie Institution of Washington] [Carnegie Institution of Washington; Chow, P [HPCAT Geophysical Lab, Argonne, IL] [HPCAT Geophysical Lab, Argonne, IL; Fultz, B. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena

    2013-01-01T23:59:59.000Z

    Inelastic neutron scattering and nuclear resonant inelastic x-ray scattering were used to determine the phonon densities of states of face-centered-cubic Ni-Fe alloys. Increasing Fe concentration results in an average softening of the phonon modes. Chemical ordering of the Ni0.72Fe0.28 alloy results in a reduction of the partial vibrational entropy of the Fe atoms but does not significantly change the partial vibrational entropy of the Ni atoms. Changes in the phonon densities of states with composition and chemical ordering are discussed and analyzed with a cluster expansion method.

  1. 2. HIGH-LOv~ JUNCTION FORY_,\\'UO AN EXPERIMENTAL STUDY OF AL-ALLOYED:'p+ JUNCT;[ONS FOR SSF SOLAR CELT.S As temperature rises en..!."

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    . Luque formed. The deposited Al diss Instituto de Energia Solar {E.T,S,I.T,} phase composition given2. HIGH-LOv~ JUNCTION FORY_,\\'UO AN EXPERIMENTAL STUDY OF AL-ALLOYED:§'p+ JUNCT;[ONS FOR SSF SOLAR+pp+ bifacial SSF solar cells are used to experimentally analyse the interphase in a similar way a 5i layer

  2. Entropy production by simple electrical circuits

    E-Print Network [OSTI]

    E. N. Miranda; S. Nikolskaia

    2012-08-13T23:59:59.000Z

    The entropy production by simple electrical circuits (R, RC, RL) is analyzed. It comes out that the entropy production is minimal, in agreement with a well known theorem due to Prigogine. In this way, it is wrong a recent result by Zupanovic, Juretic and Botric (Physica Review E 70, 056198) who claimed that the entropy production in simple electrical circuits is a maximum

  3. When are microcircuits well-modeled by maximum entropy methods?

    E-Print Network [OSTI]

    2010-07-20T23:59:59.000Z

    POSTER PRESENTATION Open Access When are microcircuits well-modeled by maximum entropy methods? Andrea K Barreiro1*, Eric T Shea-Brown1, Fred M Rieke2,3, Julijana Gjorgjieva4 From Nineteenth Annual Computational Neuroscience Meeting: CNS*2010 San... Antonio, TX, USA. 24-30 July 2010 Recent experiments in retina and cortex have demon- strated that pairwise maximum entropy (PME) methods can approximate observed spiking patterns to a high degree of accuracy [1,2]. In this paper we examine...

  4. Origin of Entropy Convergence in Hydrophobic Hydration and Protein Folding

    SciTech Connect (OSTI)

    Garde, S.; Hummer, G.; Garcia, A.E.; Paulaitis, M.E.; Pratt, L.R. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); [Center for Molecular and Engineering Thermodynamics, Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716 (United States); [Department of Chemical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    1996-12-01T23:59:59.000Z

    An information theory model of hydrophobic effects is used to construct a molecular explanation why hydrophobic solvation entropies of protein unfolding measured by high sensitivity calorimetry converge to zero at a common convergence temperature. The entropy convergence follows directly from the weak temperature dependence of occupancy fluctuations {l_angle}{delta}{ital n}{sup 2}{r_angle} for molecular-scale volumes in water. The macroscopic expression of the contrasting entropic behavior of water relative to common organic solvents is the {ital relative} temperature insensitivity of the water isothermal compressibility compared to hydrocarbon liquids. The information theory model used provides a quantitative description of small molecule hydration and, in addition, predicts that the value of the entropy at convergence is slightly {ital negative}. Interpretations of entropic contributions to protein folding should account for this result. {copyright} {ital 1996 The American Physical Society.}

  5. A Study on Formation and Thermal Stability of Nano-sized Oxide Clusters in Mechanically Alloyed NiAl for High Temperature Applications

    E-Print Network [OSTI]

    KIM, YONG-DEOG

    2012-01-01T23:59:59.000Z

    alloying and spark-plasma sintering, in Designing,and consolidated by spark plasma sintering. 2000. Trans Techalloying and spark-plasma sintering. 2004. Trans Tech

  6. Testing Issues with OS-based Entropy Peter Gutmann

    E-Print Network [OSTI]

    Gutmann, Peter

    /byte ·First order = 0 bits/byte Entropy Estimation (ctd) Problems with high-order Markov models ·Consumes huge model #12;Adapting Faster Statistical compressors ·Allocate codewords to each source symbol to minimise average code length Dictionary compressors ·Replace a string of symbols with a reference to a previous

  7. Holographic Studies of Entanglement Entropy in Superconductors

    E-Print Network [OSTI]

    Tameem Albash; Clifford V. Johnson

    2012-05-31T23:59:59.000Z

    We present the results of our studies of the entanglement entropy of a superconducting system described holographically as a fully back-reacted gravity system, with a stable ground state. We use the holographic prescription for the entanglement entropy. We uncover the behavior of the entropy across the superconducting phase transition, showing the reorganization of the degrees of freedom of the system. We exhibit the behaviour of the entanglement entropy from the superconducting transition all the way down to the ground state at T=0. In some cases, we also observe a novel transition in the entanglement entropy at intermediate temperatures, resulting from the detection of an additional length scale.

  8. Three-dimensional characterization of bainitic microstructures in low-carbon high-strength low-alloy steel studied by electron backscatter diffraction

    SciTech Connect (OSTI)

    Kang, J.S. [Department of Materials Science and Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Technical Research Laboratories, POSCO, Pohang 790-300 (Korea, Republic of); Seol, Jae-Bok, E-mail: j.seol@mpie.de [Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, D-40237 Düsseldorf (Germany); Park, C.G. [Department of Materials Science and Engineering, POSTECH, Pohang 790-784 (Korea, Republic of)

    2013-05-15T23:59:59.000Z

    We investigated the microstructural evolution of high strength low alloy steel, Fe–2.0Mn–0.15Si–0.05C (wt.%), by varying the continuous cooling rates from 1 K/s to 50 K/s using three-dimensional electron backscatter diffraction and transmission electron microscopy. Granular bainitic microstructure was prevalent under a slow cooling rate of 1–10 K/s, while lath-type bainite was dominant at a high cooling rate of 50 K/s. The acicular ferrite that was the major microstructure under the intermediate ranges of cooling rates between 10 K/s and 30 K/s was tangled with each other, leading to a three-dimensional interwoven structure with highly misoriented grains. Because of the formation of three-dimensional structures, we propose that the terms “acicular ferrite” and “bainitic ferrite,” which are currently used in steel, be replaced by the terms “interwoven acicular bainite” and “lath bainite,” respectively. Moreover, we also confirmed that the cooling rate is an important factor in determining whether bainitic microstructures occur in the form of granular bainite, interwoven bainite, or lath bainite. - Highlights: • The morphology of bainitic grains was characterized by 3D-EBSD. • The ‘interwoven bainite’ and ‘lath bainite’ were suggested. • Interwoven bainite consisted of lenticular plates that were interlinked in 3D regime. • The packets of lath bainite were aligned in a specific direction.

  9. Mo-Si-B Alloy Development J. H. Schneibel

    E-Print Network [OSTI]

    Ritchie, Robert

    are relatively low. For example, the nickel-base ODS alloy MA754 has a 1000 h rupture strength of 78 MPa at 1150°C and the iron- base ODS alloy MA956 has a 100 h rupture strength of 51 MPa at 1100°C [1]. Also, these ODS alloys have high stress exponents which makes them prone to catastrophic fracture in creep since

  10. LEB tuner made out of titanium alloy

    SciTech Connect (OSTI)

    Goren, Y.; Campbell, B.

    1991-09-01T23:59:59.000Z

    A proposed design of a closed shell tuner for the LEB cavity is presented. The tuner is made out of Ti alloy which has a high electrical resistivity as well as very good mechanical strength. Using this alloy results in a substantial reduction in the eddy current heating as well as allowing for faster frequency control. 9 figs.

  11. Influence of germanium and the melting method on the mechanical properties of NM23KhYu alloy at high temperatures

    SciTech Connect (OSTI)

    Lebedev, D.V.; Rozonova, V.M.

    1986-05-01T23:59:59.000Z

    The purpose of the investigation was to increase the plasticity and ductility of NM233KhYu alloy without a detrimental effect on its service properties, selection of methods evaluation of placticity and ductility at increased temperatures, and establishment on the basis of the results obtained of the optimum temperature range for hot working by pressure. To evaluate the mechanical properties at increased temperature tension, impact strength and torsion tests were made. Alloying with germanium of NM23KhYu alloy leads to a two-to-three-time increase in its impact strength. Electron beam remelting of NM23KhYu alloy with germanium increases the impact strength, and the characteristics of plasticity by 1.5-2 times in comparison with the similar properties of this alloy produced by vacuum induction melting.

  12. High-temperature characteristics of Seebeck coefficients for AlInN alloys grown by metalorganic vapor phase epitaxy

    E-Print Network [OSTI]

    Gilchrist, James F.

    importance for efficient thermal management in high power devices. The availability of III- nitride the calculation of surface and interface energies J. Appl. Phys. 110, 113910 (2011) A strain relief mode of Physics. [doi:10.1063/1.3624761] I. INTRODUCTION High power density and high-temperature requirements

  13. Metal alloy identifier

    DOE Patents [OSTI]

    Riley, William D. (Avondale, MD); Brown, Jr., Robert D. (Avondale, MD)

    1987-01-01T23:59:59.000Z

    To identify the composition of a metal alloy, sparks generated from the alloy are optically observed and spectrographically analyzed. The spectrographic data, in the form of a full-spectrum plot of intensity versus wavelength, provide the "signature" of the metal alloy. This signature can be compared with similar plots for alloys of known composition to establish the unknown composition by a positive match with a known alloy. An alternative method is to form intensity ratios for pairs of predetermined wavelengths within the observed spectrum and to then compare the values of such ratios with similar values for known alloy compositions, thereby to positively identify the unknown alloy composition.

  14. Entropy of Isolated Horizons revisited

    E-Print Network [OSTI]

    Rudranil Basu; Romesh K. Kaul; Parthasarathi Majumdar

    2009-07-29T23:59:59.000Z

    The decade-old formulation of the isolated horizon classically and within loop quantum gravity, and the extraction of the microcanonical entropy of such a horizon from this formulation, is reviewed, in view of recent renewed interest. There are two main approaches to this problem: one employs an SU(2) Chern-Simons theory describing the isolated horizon degrees of freedom, while the other uses a reduced U(1) Chern-Simons theory obtained from the SU(2) theory, with appropriate constraints imposed on the spectrum of boundary states `living' on the horizon. It is shown that both these ways lead to the same infinite series asymptotic in horizon area for the microcanonical entropy of an isolated horizon. The leading area term is followed by an unambiguous correction term logarithmic in area with a coefficient $-\\frac32$, with subleading corrections dropping off as inverse powers of the area.

  15. Entropy of isolated horizons revisited

    SciTech Connect (OSTI)

    Basu, Rudranil; Kaul, Romesh K.; Majumdar, Parthasarathi [SN Bose National Centre for Basic Sciences, Kolkata 700 098 (India); Institute of Mathematical Sciences, Chennai 600 113 (India); Saha Institute of Nuclear Physics, Kolkata 700 064 (India)

    2010-07-15T23:59:59.000Z

    The decade-old formulation of the isolated horizon classically and within loop quantum gravity, and the extraction of the microcanonical entropy of such a horizon from this formulation, is reviewed, in view of recent renewed interest. There are two main approaches to this problem: one employs an SU(2) Chern-Simons theory describing the isolated horizon degrees of freedom, while the other uses a reduced U(1) Chern-Simons theory obtained from the SU(2) theory, with appropriate constraints imposed on the spectrum of boundary states ''living'' on the horizon. It is shown that both these ways lead to the same infinite series asymptotic in the horizon area for the microcanonical entropy of an isolated horizon. The leading area term is followed by an unambiguous correction term logarithmic in area with a coefficient -(3/2), with subleading corrections dropping off as inverse powers of the area.

  16. Dark energy from entanglement entropy

    E-Print Network [OSTI]

    Salvatore Capozziello; Orlando Luongo

    2013-03-06T23:59:59.000Z

    We show that quantum decoherence, in the context of observational cosmology, can be connected to the cosmic dark energy. The decoherence signature could be characterized by the existence of quantum entanglement between cosmological eras. As a consequence, the Von Neumann entropy related to the entanglement process, can be compared to the thermodynamical entropy in a homogeneous and isotropic universe. The corresponding cosmological models are compatible with the current observational bounds being able to reproduce viable equations of state without introducing {\\it a priori} any cosmological constant. In doing so, we investigate two cases, corresponding to two suitable cosmic volumes, $V\\propto a^3$ and $V\\propto H^{-3}$, and find two models which fairly well approximate the current cosmic speed up. The existence of dark energy can be therefore reinterpreted as a quantum signature of entanglement, showing that the cosmological constant represents a limiting case of a more complicated model derived from the quantum decoherence.

  17. Entropy production in thermostats II

    E-Print Network [OSTI]

    Nurlan S. Dairbekov; Gabriel P. Paternain

    2006-10-08T23:59:59.000Z

    We show that an arbitrary Anosov Gaussian thermostat close to equilibrium has positive entropy poduction unless the external field $E$ has a global potential. The configuration space is allowed to have any dimension and magnetic forces are also allowed. We also show the following non-perturbative result. Suppose a Gaussian thermostat satisfies \\[K_{w}(\\sigma)+{1/4}|E_{\\sigma}|^2<0\\] for every 2-plane $\\sigma$, where $K_{w}$ is the sectional curvature of the associated Weyl connection and $E_{\\sigma}$ is the orthogonal projection of $E$ onto $\\sigma$. Then the entropy production of any SRB measure is positive unless $E$ has a global potential. A related non-perturbative result is also obtained for certain generalized thermostats on surfaces.

  18. Vehicle Technologies Office Merit Review 2015: High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  19. Vehicle Technologies Office Merit Review 2014: Development of Advanced High Strength Cast Alloys for Heavy Duty Engines

    Broader source: Energy.gov [DOE]

    Presentation given by Caterpillar at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about development of advanced high...

  20. Vehicle Technologies Office Merit Review 2015: Development of Advanced High Strength Cast Alloys for Heavy Duty Engines

    Broader source: Energy.gov [DOE]

    Presentation given by Caterpillar at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about development of advanced high...

  1. Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt

    SciTech Connect (OSTI)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

    2008-01-01T23:59:59.000Z

    Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.

  2. Remarks on Renormalization of Black Hole Entropy

    E-Print Network [OSTI]

    Sang Pyo Kim; Sung Ku Kim; Kwang-Sup Soh; Jae Hyung Yee

    1996-07-07T23:59:59.000Z

    We elaborate the renormalization process of entropy of a nonextremal and an extremal Reissner-Nordstr\\"{o}m black hole by using the Pauli-Villars regularization method, in which the regulator fields obey either the Bose-Einstein or Fermi-Dirac distribution depending on their spin-statistics. The black hole entropy involves only two renormalization constants. We also discuss the entropy and temperature of the extremal black hole.

  3. Rényi entropy flows from quantum heat engines

    E-Print Network [OSTI]

    Mohammad H. Ansari; Yuli V. Nazarov

    2015-03-20T23:59:59.000Z

    We evaluate Renyi entropy flows from generic quantum heat engines (QHE) to a weakly-coupled probe environment kept in thermal equilibrium. We show that the flows are determined not only by heat flow but also by a quantum coherent flow that can be separately measured in experiment apart from the heat flow measurement. The same pertains to Shanon entropy flow. This appeals for a revision of the concept of entropy flows in quantum nonequlibrium thermodynamics.

  4. A Study on Formation and Thermal Stability of Nano-sized Oxide Clusters in Mechanically Alloyed NiAl for High Temperature Applications

    E-Print Network [OSTI]

    KIM, YONG-DEOG

    2012-01-01T23:59:59.000Z

    IN MECHANICALLY ALLOYED ODS STEEL. Journal of Materialscompressive properties of ODS MA NiAl. Scripta Materialia,TEM imaging and EELS study of ODS particles and argon-filled

  5. High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium

    SciTech Connect (OSTI)

    Lechtenberg, T.A.; Stevenson, R.D.; Johnson, W.R.

    1980-05-01T23:59:59.000Z

    Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 1000/sup 0/C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900.

  6. Entropy generation in a chemical reaction

    E-Print Network [OSTI]

    E. N. Miranda

    2012-08-10T23:59:59.000Z

    Entropy generation in a chemical reaction is analyzed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first order reaction is used to show that entropy production is always positive. A second approach assumes that the reaction is near equilibrium to prove that the entropy generated is always greater than zero, without any reference to the kinetics of the reaction. Finally, it is shown that entropy generation is related to fluctuations in the number of particles at equilibrium, i.e. it is associated to a microscopic process.

  7. Holographic entropy bounds in the inflationary universe

    E-Print Network [OSTI]

    Y. S. Myung

    2003-01-13T23:59:59.000Z

    We introduce the relation between the holographic entropy bounds and the inflationary universe. First the holographic entropy bounds for radiation-dominated universe, radiation-dominated universe with a positive cosmological constant are introduced. For an exact de Sitter phase, we use the maximal entropy bound. We classify the inflation based on the quasi-de Sitter spacetime into three steps: slow-roll period of inflation, epoch of reheating, and radiation-dominated era. Then we study how to apply three entropy bounds to the three steps of the inflation. Finally we discuss our results.

  8. Preparations of rare earth-iron alloys by thermite reduction

    DOE Patents [OSTI]

    Schmidt, Frederick A. (Ames, IA); Peterson, David T. (Ames, IA); Wheelock, John T. (Nevada, IA)

    1986-09-16T23:59:59.000Z

    An improved method for the preparation of high-purity rare earth-iron alloys by the aluminothermic reduction of a mixture of rare earth and iron fluorides.

  9. al zn alloy: Topics by E-print Network

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

    NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  10. alloying elements al: Topics by E-print Network

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

    NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  11. alloy steels simulations: Topics by E-print Network

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

    NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  12. alloys transformation induced: Topics by E-print Network

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

    NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  13. alloy c-22 induced: Topics by E-print Network

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

    NiAl NANOLAMINATES . Open Access Theses and Dissertations Summary: ??To characterize the self-propagating, high-temperature exothermic alloying reactions of NiAl nanoscaled...

  14. alloy steels etudes: Topics by E-print Network

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

    y-dend rites. (Note: primary y Cambridge, University of 2 Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels Engineering Websites Summary: Estimation of...

  15. alloy performance unresolved: Topics by E-print Network

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

    Computer Technologies and Information Sciences Websites Summary: Fatigue Localized corrosion degrades fatigue performance of high strength aluminum alloys. The expense and...

  16. alloy coated steels: Topics by E-print Network

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

    y-dend rites. (Note: primary y Cambridge, University of 2 Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels Engineering Websites Summary: Estimation of...

  17. alloy steel transition: Topics by E-print Network

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

    y-dend rites. (Note: primary y Cambridge, University of 2 Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels Engineering Websites Summary: Estimation of...

  18. alloy coated steel: Topics by E-print Network

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

    y-dend rites. (Note: primary y Cambridge, University of 2 Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels Engineering Websites Summary: Estimation of...

  19. alloy films deposited: Topics by E-print Network

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

    memory alloy Elastic modulus Wrinkling Thermoelastic strain in a polycrystalline Fe-Pd thin film 50 High-resolution photometric optical monitoring for thin-film deposition...

  20. alloy fatigue strength: Topics by E-print Network

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

    of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United ... Needham, William...

  1. alloy tool steel: Topics by E-print Network

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

    of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United ... Needham, William...

  2. Adhesion of anodic films on aluminum-lithium alloys

    SciTech Connect (OSTI)

    Skeldon, P.; Zhou, X.; Thompson, G.E.; Wood, G.C. (Univ. of Manchester Institute of Science and Technology (United Kingdom). Corrosion and Protection Centre); Habazaki, H. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research); Shimizu, K. (Keio Univ., Hiyoshi, Yokohama (Japan). University Chemical Lab.)

    1999-06-01T23:59:59.000Z

    During anodizing of certain binary Al alloys, the growing anodic oxide film detaches from the alloy substrate, subsequently allowing access of the electrolyte to the underlying bare metal and re-anodizing at a high current density. An Al-3% Li alloy was shown to reveal these phenomena, which are associated with the development of voids at the alloy/film interface as the film thickens. The development of voids, assisting the film detachment, was attributed to the reduced volume of lithium oxide (Li[sub 2]O) formed at the alloy/film interface and compared to that of alumina (Al[sub 2]O[sub 3]).

  3. Time dependence of Hawking radiation entropy

    SciTech Connect (OSTI)

    Page, Don N., E-mail: profdonpage@gmail.com [Department of Physics, 4-181 CCIS, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

    2013-09-01T23:59:59.000Z

    If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4?M{sub 0}{sup 2}, or about 7.509M{sub 0}{sup 2} ? 6.268 × 10{sup 76}(M{sub 0}/M{sub s}un){sup 2}, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M{sub 0}{sup 2} ? 1.254 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}, and then decreases back down to 4?M{sub 0}{sup 2} = 1.049 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}.

  4. Direct measurement of isothermal flow stress of metals at elevated temperatures and high strain rates with application to Ta and Ta-W alloys

    SciTech Connect (OSTI)

    Nemat-Nasser, S.; Isaacs, J.B. [Univ. of California, San Diego, La Jolla, CA (United States)] [Univ. of California, San Diego, La Jolla, CA (United States)

    1997-03-01T23:59:59.000Z

    A technique is developed for measuring the flow stress of metals over a broad range of strains, strain rates, and temperatures, in uniaxial compression. It utilizes a recent, enhanced version of the classical (Kolsky) compression split Hopkinson bar, in which a sample is subjected to a single stress pulse of a predefined profile, and then recovered without being subjected to any other additional loading. For the present application, the UCSD`s split Hopkinson bar is further enhanced by the addition of a new mechanism by means of which the incident and transmission bars of the split Hopkinson construction are moved into a constant-temperature furnace containing the sample, and gently brought into contact with the sample, as the elastic stress pulse reaches and loads the sample. Using several samples of the same material and testing them at the same strain rate and temperature, but different incremental strains, an accurate estimate of the material`s isothermal flow stress can be obtained. Additionally, the modified Hopkinson technique allows the direct measurement of the change in the (high strain-rate) flow stress with a change of the strain rate, while the strain and temperature are kept constant, i.e., the strain rate can be increased or decreased during the high strain-rate test. The technique is applied to obtain both quasi-isothermal and adiabatic flow stresses of tantalum (Ta) and a tantalum-tungsten (Ta-W) alloy at elevated temperatures. These experimental results show the flow stress of these materials to be controlled by a simple long-range plastic-strain-dependent barrier, and a short-range thermally activated Peierls mechanism. For tantalum, a model which fits the experimental data over strains from a few to over 100%, strain rates from quasi-static to 40,000/s, and temperatures from {minus}200 to 1,000 C, is presented and discussed.

  5. Entropy and Energy: Toward a Definition of Physical Sustainability

    E-Print Network [OSTI]

    Hermanowicz, Slawomir W

    2005-01-01T23:59:59.000Z

    usefulness of entropy-energy definition of sustainability asEntropy and Energy: Toward a Definition of Physicaland energy should be included in the desired definition of

  6. absolute configurational entropies: Topics by E-print Network

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

    entropy -- which we evaluate with two different methods -- we show that a configurational entropy maximum is observed at a temperature close to that of the diffusivity maximum. Our...

  7. Entropy evolution law in a laser process

    E-Print Network [OSTI]

    Jun-hua Chen; Hong-yi Fan

    2012-09-21T23:59:59.000Z

    For the first time, we obtain the entropy variation law in a laser process after finding the Kraus operator of the master equation describing the laser process with the use of the entangled state representation. The behavior of entropy is determined by the competition of the gain and damping in the laser process. The photon number evolution formula is also obtained.

  8. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems

    E-Print Network [OSTI]

    Hanel, Rudolf; Gell-Mann, Murray

    2014-01-01T23:59:59.000Z

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems, by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there exists an ongoing controversy whether the notion of the maximum entropy principle can be extended in a meaningful way to non-extensive, non-ergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for non-ergodic and complex statistical systems if their relative entropy can be factored into a general...

  9. Cesium iodide alloys

    DOE Patents [OSTI]

    Kim, Hyoun-Ee (Oak Ridge, TN); Moorhead, Arthur J. (Knoxville, TN)

    1992-01-01T23:59:59.000Z

    A transparent, strong CsI alloy havign additions of monovalent iodides. Although the perferred iodide is AgI, RbI and CuI additions also contribute to an improved polycrystalline CsI alloy.

  10. The structural and mechanical properties of a Cu??Zr??(at. %) alloy processed by High-Velocity-Injection (HVI)

    E-Print Network [OSTI]

    Hays, Charles C.

    1986-01-01T23:59:59.000Z

    /vacuum coupled pressure gradient. The molten jet rapidly solidifies, as it is in good thermal contact wi th the cir- cular walls of the copper channel. This process (melting and injection) is carried out in inert protective atmospheres (helium). The samples... produced are in the form of cylindrical rods with large length to diameter ratios (40:1). The samples exhibit a good sur- face finish and are of high density. The structural and mechanical characterization of the Cu6 Zr 0(at. %%u) samples produced...

  11. Single Interval Rényi Entropy At Low Temperature

    E-Print Network [OSTI]

    Bin Chen; Jie-qiang Wu

    2015-01-06T23:59:59.000Z

    In this paper, we calculate the R\\'enyi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in $e^{-\\pi/TL}$ explicitly. On the other hand, we compute the same R\\'enyi entropy holographically. After considering the dependence of the R\\'enyi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic R\\'enyi entropy. We furthermore extend the analysis in Xi Dong's paper to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of R\\'enyi entropy in AdS$_3$/CFT$_2$ correspondence, even with thermal effect.

  12. Entanglement Entropy at Large Central Charge

    E-Print Network [OSTI]

    Thomas Hartman

    2013-03-27T23:59:59.000Z

    Two-dimensional conformal field theories with a large central charge and a small number of low-dimension operators are studied using the conformal block expansion. A universal formula is derived for the Renyi entropies of N disjoint intervals in the ground state, valid to all orders in a series expansion. This is possible because the full perturbative answer in this regime comes from the exchange of the stress tensor and other descendants of the vacuum state. Therefore, the Renyi entropy is related to the Virasoro vacuum block at large central charge. The entanglement entropy, computed from the Renyi entropy by an analytic continuation, decouples into a sum of single-interval entanglements. This field theory result agrees with the Ryu-Takayanagi formula for the holographic entanglement entropy of a 2d CFT, applied to any number of intervals, and thus can be interpreted as a microscopic calculation of the area of minimal surfaces in 3d gravity.

  13. The role of entropy in magnetotail dynamics

    SciTech Connect (OSTI)

    Birn, Joachim [Los Alamos National Laboratory; Zaharia, Sorin [Los Alamos National Laboratory; Hesse, Michael [NASA/GSFC; Schindler, K [INSTITUT FOR THEORETISCHE

    2008-01-01T23:59:59.000Z

    The role of entropy conservation and loss in magnetospheric dynamics, particularly in relation to substorm phases, is discussed on the basis of MHD theory and simulations, using comparisons with PIC simulations for validation. Entropy conservation appears to be a crucial element leading to the formation of thin embedded current sheets in the late substorm growth phase and the potential loss of equilibrium. Entropy loss (in the form of plasmoids) is essential in the earthward transport of flux tubes (bubbles, bursty bulk flows). Entropy loss also changes the tail stability properties and may render ballooning modes unstable and thus contribute to cross-tail variability. We illustrate these effects through results from theory and simulations. Entropy conservation also governs the accessibility of final states of evolution and the amount of energy that may be released.

  14. Solid solution lithium alloy cermet anodes

    DOE Patents [OSTI]

    Richardson, Thomas J.

    2013-07-09T23:59:59.000Z

    A metal-ceramic composite ("cermet") has been produced by a chemical reaction between a lithium compound and another metal. The cermet has advantageous physical properties, high surface area relative to lithium metal or its alloys, and is easily formed into a desired shape. An example is the formation of a lithium-magnesium nitride cermet by reaction of lithium nitride with magnesium. The reaction results in magnesium nitride grains coated with a layer of lithium. The nitride is inert when used in a battery. It supports the metal in a high surface area form, while stabilizing the electrode with respect to dendrite formation. By using an excess of magnesium metal in the reaction process, a cermet of magnesium nitride is produced, coated with a lithium-magnesium alloy of any desired composition. This alloy inhibits dendrite formation by causing lithium deposited on its surface to diffuse under a chemical potential into the bulk of the alloy.

  15. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

    Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)

    2012-06-12T23:59:59.000Z

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  16. 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

    E-Print Network [OSTI]

    Ritchie, IAltenberger, RKNalla, YSano LWagner, RO

    2013-01-01T23:59:59.000Z

    deep rolled as-quenched aluminium alloy AA6110 at elevatedT, editor. Aluminium Alloys, Theory and Applications,shock processing of aluminium alloys. Application to high

  17. 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

    E-Print Network [OSTI]

    Ritchie, IAltenberger, RKNalla, YSano LWagner, RO

    2013-01-01T23:59:59.000Z

    T, editor. Aluminium Alloys, Theory and Applications,deep rolled as-quenched aluminium alloy AA6110 at elevatedshock processing of aluminium alloys. Application to high

  18. Oxidation of advanced steam turbine alloys

    SciTech Connect (OSTI)

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.

    2006-03-01T23:59:59.000Z

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  19. JOM Volume 63, Number 2 (2011): 48-52 High strain rate compressive response of magnesium-aluminum alloy/fly ash cenosphere composites

    E-Print Network [OSTI]

    Gupta, Nikhil

    2011-01-01T23:59:59.000Z

    , and sound and vibration damping. Low strength of open and closed-cell foams containing gas porosity distribution in syntactic foams is usually much more uniform compared to the gas filled foams. Presence half of which is dumped in landfills. In the present work, a cast magnesium-aluminum alloy, AZ91D

  20. Entropy viscosity Jean-Luc Guermond, B. Popov

    E-Print Network [OSTI]

    Guermond, Jean-Luc

    Entropy viscosity Jean-Luc Guermond, B. Popov Department of Mathematics Texas A&M University-Luc Guermond, B. Popov Residual/Entropy viscosity #12;Acknowledgments Collaborator: Richard Pasquetti, Univ/Entropy viscosity #12;Outline 1 TRANSPORT EQUATION Jean-Luc Guermond, B. Popov Residual/Entropy viscosity #12

  1. Expanding the Area of Gravitational Entropy

    E-Print Network [OSTI]

    R. B. Mann

    2002-11-12T23:59:59.000Z

    I describe how gravitational entropy is intimately connected with the concept of gravitational heat, expressed as the difference between the total and free energies of a given gravitational system. From this perspective one can compute these thermodyanmic quantities in settings that go considerably beyond Bekenstein's original insight that the area of a black hole event horizon can be identified with thermodynamic entropy. The settings include the outsides of cosmological horizons and spacetimes with NUT charge. However the interpretation of gravitational entropy in these broader contexts remains to be understood.

  2. CORROSION OF Fe-10Al-Cr ALLOYS BY COAL CHAR

    E-Print Network [OSTI]

    Gordon, B.A.

    2011-01-01T23:59:59.000Z

    owned rights. LBL-6946 Corrosion of Fe-lOAl-Cr Alloys byOctober, 1977 Abstract Corrosion of iron-base alloys at 982°high-temperature induced corrosion are probably sulfides and

  3. An approach to comparing Kolmogorov-Sinai and permutation entropy

    E-Print Network [OSTI]

    Valentina A. Unakafova; Anton M. Unakafov; Karsten Keller

    2015-03-09T23:59:59.000Z

    In this paper we investigate a quantity called conditional entropy of ordinal patterns, akin to the permutation entropy. The conditional entropy of ordinal patterns describes the average diversity of the ordinal patterns succeeding a given ordinal pattern. We observe that this quantity provides a good estimation of the Kolmogorov-Sinai entropy in many cases. In particular, the conditional entropy of ordinal patterns of a finite order coincides with the Kolmogorov-Sinai entropy for periodic dynamics and for Markov shifts over a binary alphabet. Finally, the conditional entropy of ordinal patterns is computationally simple and thus can be well applied to real-world data.

  4. Effect of thermally stable Cu- and Mg-rich aluminides on the high temperature strength of an AlSi12CuMgNi alloy

    SciTech Connect (OSTI)

    Asghar, Z., E-mail: zhdasghar@yahoo.com [Materials Division, Directorate of Technology, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Vienna University of Technology, Institute of Materials Science and Technology, Karlsplatz 13/308, A-1040 Vienna (Austria); Requena, G. [Vienna University of Technology, Institute of Materials Science and Technology, Karlsplatz 13/308, A-1040 Vienna (Austria); Zahid, G.H.; Rafi-ud-Din [Materials Division, Directorate of Technology, PINSTECH, P. O. Nilore, Islamabad (Pakistan)

    2014-02-15T23:59:59.000Z

    The internal architecture of an AlSi12CuMgNi piston alloy, revealed by synchrotron tomography, consists of three dimensional interconnected hybrid networks of Cu-rich aluminides, Mg-rich aluminides and eutectic/primary Si embedded in an ?-Al matrix. The strength at room temperature and at 300°C is studied as a function of solution treatment time at 490°C and compared with results previously reported for an AlSi12Ni alloy. The addition of 1 wt% Cu and 1 wt% Mg to AlSi12CuMgNi increases the room temperature strength by precipitation hardening while the strength at 300°C is similar for both alloys in as-cast condition. The strength of AlSi12CuMgNi decreases with solution treatment time and stabilizes at 4 h solution treatment. The effect of solution treatment time on the strength of the AlSi12CuMgNi alloy is less pronounced than for the AlSi12Ni alloy both at room temperature and at 300°C. - Highlights: • The 3D microstructure of AlSi12CuMgNi is revealed by synchrotron tomography. • An imaging analysis procedure to segment phases with similar contrasts is presented. • 1 wt% Cu and Mg results in the formation of 3D networks of rigid phases. • AlSi12CuMgNi is stronger than AlSi12Ni owing to the stability of the 3D networks.

  5. High-Temperature Aluminum Alloys

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  6. Entropy generation minimization of a heat and mass exchanger for use in a humidification-dehumidification desalination system

    E-Print Network [OSTI]

    Thiel, Gregory P

    2012-01-01T23:59:59.000Z

    The physical mechanisms of entropy generation in a condenser with high fractions of non-condensable gases are examined using control volume, scaling, and boundary layer techniques, with the aim of defining a criterion for ...

  7. Time evolution of gluon coherent state and its von Neumann entropy in heavy-ion collisions

    E-Print Network [OSTI]

    Hideaki Iida; Teiji Kunihiro; Akira Ohnishi; Toru T. Takahashi

    2014-10-27T23:59:59.000Z

    We propose a new prescription for evaluating a von Neumann entropy in the initial stage of high-energy heavy-ion collisions utilizing the time evolution of classical Yang-Mills (CYM) field: The von Neumann entropy is computed for the quantum coherent states constructed so as to give the classical gluon fields as the expectation values. The entropy is to be liberated when the complete decoherence is achieved. As a demonstration, the time evolution of the CYM dynamics is solved with an initial condition which mimics the Glasma state, though in a non-expanding geometry; the Glasma state is characterized by the longitudinal color-electric and -magnetic fields with gluon fields' fluctuations around it. We find that the initial longitudinal fluctuations of the fields play essential roles for the entropy production in two ways: First, the field fluctuations at $t=0$ themselves act as a source of the von Neumann entropy prepared before the time evolution. Second, the initial fluctuations triggers field instabilities, and hence the larger the strength of them, the more the entropy production at later time.

  8. On Page's examples challenging the entropy bound

    E-Print Network [OSTI]

    Jacob D. Bekenstein

    2000-09-21T23:59:59.000Z

    According to the entropy bound, the entropy of a complete physical system can be universally bounded in terms of its circumscribing radius and total gravitating energy. Page's three recent candidates for counterexamples to the bound are here clarified and refuted by stressing that the energies of all essential parts of the system must be included in the energy the bound speaks about. Additionally, in response to an oft heard claim revived by Page, I give a short argument showing why the entropy bound is obeyed at low temperatures by a complete system. Finally, I remark that Page's renewed appeal to the venerable ``many species'' argument against the entropy bound seems to be inconsistent with quantum field theory.

  9. Entropy for theories with indefinite causal structure

    E-Print Network [OSTI]

    Sonia Markes; Lucien Hardy

    2009-10-07T23:59:59.000Z

    Entropy is a concept that has traditionally been reliant on a definite notion of causality. However, without a definite notion of causality, the concept of entropy is not all lost. Indefinite causal structure results from combining probabilistic predictions and dynamical space-time. Combining the probabilistic nature of quantum theory and dynamical treatment space-time from general relativity is an approach to the problem of quantum gravity. The causaloid framework lays the mathematical groundwork to be able to treat indefinite causal structure. In this paper, we build on the causaloid mathematics and define a causally-unbiased entropy for an indefinite causal structure. In defining a causally-unbiased entropy, there comes about an emergent idea of causality in the form of a measure of causal connectedness, termed the Q factor.

  10. Entropy Generation Analysis of Desalination Technologies

    E-Print Network [OSTI]

    Mistry, Karan Hemant

    Increasing global demand for fresh water is driving the development and implementation of a wide variety of seawater desalination technologies. Entropy generation analysis, and specifically, Second Law efficiency, is an ...

  11. Entanglement Entropy of Magnetic Electron Stars

    E-Print Network [OSTI]

    Tameem Albash; Clifford V. Johnson; Scott MacDonald

    2015-04-08T23:59:59.000Z

    We study the behavior of the entanglement entropy in $(2+1)$--dimensional strongly coupled theories via the AdS/CFT correspondence. We consider theories at a finite charge density with a magnetic field, with their holographic dual being Einstein-Maxwell-Dilaton theory in four dimensional anti--de Sitter gravity. Restricting to black hole and electron star solutions at zero temperature in the presence of a background magnetic field, we compute their holographic entanglement entropy using the Ryu-Takayanagi prescription for both strip and disk geometries. In the case of the electric or magnetic zero temperature black holes, we are able to confirm that the entanglement entropy is invariant under electric-magnetic duality. In the case of the electron star with a finite magnetic field, for the strip geometry, we find a discontinuity in the first derivative of the entanglement entropy as the strip width is increased.

  12. Maximum entropy segmentation of broadcast news 

    E-Print Network [OSTI]

    Christensen, Heidi; Kolluru, BalaKrishna; Gotoh, Yoshihiko; Renals, Steve

    2005-01-01T23:59:59.000Z

    speech recognizer and subsequently segmenting the text into utterances and topics. A maximum entropy approach is used to build statistical models for both utterance and topic segmentation. The experimental work addresses the effect on performance...

  13. Viscosity, entropy and the viscosity to entropy density ratio; how perfect is a nucleonic fluid?

    E-Print Network [OSTI]

    Aram Z. Mekjian

    2010-09-29T23:59:59.000Z

    The viscosity of hadronic matter is studied using a classical evaluation of the scattering angle and a quantum mechanical discussion based on phase shifts from a potential. Semi classical limits of the quantum theory are presented. A hard sphere and an attractive square well potential step are each considered as well as the combined effects of both. The lowest classical value of the viscosity for an attractive potential is shown to be a hard sphere limit. The high wave number-short wavelength limits of the quantum result have scaling laws associated with it for both the viscosity and entropy. These scaling laws are similar to the Fraunhoher diffraction increase for the hard sphere geometric cross section. Specific examples for nuclear collisions are given. The importance of the nuclear tensor force and hard core is mentioned. The viscosity (eta), entropy density (s) and eta/s ratio are calculated for a gas of dilute neutrons in the unitary limit of large scattering length. Away from the unitary limit, the ratio of the interaction radius or the scattering length to the interparticle spacing introduces a variable y besides the fugacity z. The isothermal compressibility is shown to impose important constraints. The results for eta/s are compared to the AdS/CFT string theory minimum of (1/4Pi)hbar/kb to see how close a nucleonic gas is to being a perfect fluid. The eta/s ~1hbar/kb for a neutron gas in its unitary limit. The eta/s 3hbar/kb treating the nuclear scattering as billiard ball collisions. The minimum eta/s for a neutron gas occurs in regions of negative isothermal compressibility and high fugacity where higher virial terms are important. In a neutron-proton system higher virial terms are associated with a liquid-gas phase transition and critical opalescent phenomena.The type of flow-laminar,vortex, turbulent- is investigated.

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

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN); Brady, Michael P. (Oak Ridge, TN); Zhu, Jiahong (Knoxville, TN); Tortorelli, Peter F. (Knoxville, TN)

    2001-01-01T23:59:59.000Z

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

  15. Tissue Radiation Response with Maximum Tsallis Entropy

    SciTech Connect (OSTI)

    Sotolongo-Grau, O.; Rodriguez-Perez, D.; Antoranz, J. C.; Sotolongo-Costa, Oscar [UNED, Departamento de Fisica Matematica y de Fluidos, 28040 Madrid (Spain); UNED, Departamento de Fisica Matematica y de Fluidos, 28040 Madrid (Spain) and University of Havana, Catedra de Sistemas Complejos Henri Poincare, Havana 10400 (Cuba); University of Havana, Catedra de Sistemas Complejos Henri Poincare, Havana 10400 (Cuba)

    2010-10-08T23:59:59.000Z

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.

  16. Synthesis of alloys with controlled phase structure

    DOE Patents [OSTI]

    Guthrie, S.E.; Thomas, G.J.; Bauer, W.; Yang, N.Y.C.

    1999-04-20T23:59:59.000Z

    A method is described for preparing controlled phase alloys useful for engineering and hydrogen storage applications. This novel method avoids melting the constituents by employing vapor transport, in a hydrogen atmosphere, of an active metal constituent, having a high vapor pressure at temperatures {approx_equal}300 C and its subsequent condensation on and reaction with the other constituent (substrate) of an alloy thereby forming a controlled phase alloy and preferably a single phase alloy. It is preferred that the substrate material be a metal powder such that diffusion of the active metal constituent, preferably magnesium, and reaction therewith can be completed within a reasonable time and at temperatures {approx_equal}300 C thereby avoiding undesirable effects such as sintering, local compositional inhomogeneities, segregation, and formation of unwanted second phases such as intermetallic compounds. 4 figs.

  17. Reduced activation ferritic alloys for fusion

    SciTech Connect (OSTI)

    Gelles, D.S. [Pacific Northwest Lab., Richland, VA (United States)

    1992-12-31T23:59:59.000Z

    Reduced activation martensitic alloys can now be developed with properties similar to commercial counterparts, and oxide dispersion strengthened alloys are under consideration. However, low chromium Bainitic alloys with vanadium additions undergo severe irradiation hardening at low irradiation temperatures and excessive softening at high temperatures, resulting in a very restricted application window. Manganese additions result in excessive embrittlement, as demonstrated by post-irradiation Charpy impact testing. The best composition range for martensitic alloys appears to be 7 to 9 Cr and 2 W, with swelling of minor concern and low temperature irradiation embrittlement perhaps eliminated. Therefore, reduced activation martensitic steels in the 7 to 9 Cr range should be considered leading contenders for structural materials applications in power-producing fusion machines.

  18. Synthesis of alloys with controlled phase structure

    DOE Patents [OSTI]

    Guthrie, Stephen Everett (Livermore, CA); Thomas, George John (Livermore, CA); Bauer, Walter (Livermore, CA); Yang, Nancy Yuan Chi (Lafayette, CA)

    1999-04-20T23:59:59.000Z

    A method for preparing controlled phase alloys useful for engineering and hydrogen storage applications. This novel method avoids melting the constituents by employing vapor transport, in a hydrogen atmosphere, of an active metal constituent, having a high vapor pressure at temperatures .apprxeq.300 C. and its subsequent condensation on and reaction with the other constituent (substrate) of an alloy thereby forming a controlled phase alloy and preferably a single phase alloy. It is preferred that the substrate material be a metal powder such that diffusion of the active metal constituent, preferably magnesium, and reaction therewith can be completed within a reasonable time and at temperatures .apprxeq.300 C. thereby avoiding undesirable effects such as sintering, local compositional inhomogeneities, segregation, and formation of unwanted second phases such as intermetallic compounds.

  19. Monotonicity of quantum relative entropy and recoverability

    E-Print Network [OSTI]

    Mario Berta; Marius Lemm; Mark M. Wilde

    2014-12-18T23:59:59.000Z

    The relative entropy is a principal measure of distinguishability in quantum information theory, with its most important property being that it is non-increasing under noisy quantum operations. Here, we establish a remainder term for this inequality that quantifies how well one can recover from a loss of information by employing a rotated Petz recovery map. The main approach for proving this refinement is to combine the methods of [Fawzi and Renner, arXiv:1410.0664] with the notion of a relative typical subspace from [Bjelakovic and Siegmund-Schultze, arXiv:quant-ph/0307170]. It remains an open question if the same bound holds for the Petz recovery map (and not merely for a rotated Petz recovery map). A well known result states that the monotonicity of relative entropy under quantum operations is equivalent to any of the following inequalities: strong subadditivity of entropy, concavity of conditional entropy, joint convexity of relative entropy, and monotonicity of relative entropy under partial trace. We show that this equivalence holds true for refinements of all these inequalities in terms of the Petz recovery map. So either all of these refinements are true or all are false.

  20. Ductile filler metal alloys for welding nickel aluminide alloys

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); McNabb, Jeffrey D. (Lenoir City, TN); Sikka, Vinod K. (Oak Ridge, TN)

    2003-04-08T23:59:59.000Z

    Nickel aluminum alloys are welded utilizing a nickel based alloy containing zirconium but substantially free of titanium and niobium which reduces the tendency to crack.

  1. Uranium-titanium-niobium alloy

    DOE Patents [OSTI]

    Ludtka, Gail M. (Oak Ridge, TN); Ludtka, Gerard M. (Oak Ridge, TN)

    1990-01-01T23:59:59.000Z

    A uranium alloy having small additions of Ti and Nb shows improved strength and ductility in cross section of greater than one inch over prior uranium alloy having only Ti as an alloying element.

  2. Low activation ferritic alloys

    DOE Patents [OSTI]

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

    1985-02-07T23:59:59.000Z

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  3. Low activation ferritic alloys

    DOE Patents [OSTI]

    Gelles, David S. (West Richland, WA); Ghoniem, Nasr M. (Granada Hills, CA); Powell, Roger W. (Pasco, WA)

    1986-01-01T23:59:59.000Z

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  4. Linearized semiclassical initial value time correlation functions with maximum entropy analytic continuation

    E-Print Network [OSTI]

    Liu, Jian

    2008-01-01T23:59:59.000Z

    1992). J. Skilling, in Maximum entropy and Bayesian methods,1989). S. F. Gull, in Maximum entropy and Bayesian methods,with the classical maximum entropy (CME) technique (MEAC-

  5. Improved constraints on transit time distributions from argon 39: A maximum entropy approach

    E-Print Network [OSTI]

    Holzer, Mark; Primeau, Francois W

    2010-01-01T23:59:59.000Z

    Gull (1991), Bayesian maximum entropy image reconstruction,Atlantic venti- lated? Maximum entropy inversions of bottlefrom argon 39: A maximum entropy approach Mark Holzer 1,2

  6. Quantum Statistics Basis, Thermodynamic Analogies and the Degree of Confidence for Maximum Entropy Restoration and Estimation

    E-Print Network [OSTI]

    Soffer, Bernard H; Kikuchi, Ryoichi

    1994-01-01T23:59:59.000Z

    of Confidence for Maximum Entropy Restoration and EstimationApril 3, 1992) The Maximum Entropy method, using physicalare discussed. Maximum Entropy (ME) estimation has been

  7. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

    Anderson, Iver E; Rieken, Joel

    2013-12-10T23:59:59.000Z

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with an introduced reactive species than does the alloying element and wherein one or more atomizing parameters is/are modified to controllably reduce the amount of the reactive species, such as oxygen, introduced into the atomized particles so as to reduce anneal times and improve reaction (conversion) to the desired strengthening dispersoids in the matrix. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies are made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  8. Entropy-driven cutoff phenomena

    E-Print Network [OSTI]

    Carlo Lancia; Francesca R. Nardi; Benedetto Scoppola

    2012-05-03T23:59:59.000Z

    In this paper we present, in the context of Diaconis' paradigm, a general method to detect the cutoff phenomenon. We use this method to prove cutoff in a variety of models, some already known and others not yet appeared in literature, including a chain which is non-reversible w.r.t. its stationary measure. All the given examples clearly indicate that a drift towards the opportune quantiles of the stationary measure could be held responsible for this phenomenon. In the case of birth- and-death chains this mechanism is fairly well understood; our work is an effort to generalize this picture to more general systems, such as systems having stationary measure spread over the whole state space or systems in which the study of the cutoff may not be reduced to a one-dimensional problem. In those situations the drift may be looked for by means of a suitable partitioning of the state space into classes; using a statistical mechanics language it is then possible to set up a kind of energy-entropy competition between the weight and the size of the classes. Under the lens of this partitioning one can focus the mentioned drift and prove cutoff with relative ease.

  9. Intermetallic alloy welding wires and method for fabricating the same

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    1996-01-01T23:59:59.000Z

    Welding wires for welding together intermetallic alloys of nickel aluminides, nickel-iron aluminides, iron aluminides, or titanium aluminides, and preferably including additional alloying constituents are fabricated as two-component, clad structures in which one component contains the primary alloying constituent(s) except for aluminum and the other component contains the aluminum constituent. This two-component approach for fabricating the welding wire overcomes the difficulties associated with mechanically forming welding wires from intermetallic alloys which possess high strength and limited ductilities at elevated temperatures normally employed in conventional metal working processes. The composition of the clad welding wires is readily tailored so that the welding wire composition when melted will form an alloy defined by the weld deposit which substantially corresponds to the composition of the intermetallic alloy being joined.

  10. Intermetallic alloy welding wires and method for fabricating the same

    DOE Patents [OSTI]

    Santella, M.L.; Sikka, V.K.

    1996-06-11T23:59:59.000Z

    Welding wires for welding together intermetallic alloys of nickel aluminides, nickel-iron aluminides, iron aluminides, or titanium aluminides, and preferably including additional alloying constituents are fabricated as two-component, clad structures in which one component contains the primary alloying constituent(s) except for aluminum and the other component contains the aluminum constituent. This two-component approach for fabricating the welding wire overcomes the difficulties associated with mechanically forming welding wires from intermetallic alloys which possess high strength and limited ductilities at elevated temperatures normally employed in conventional metal working processes. The composition of the clad welding wires is readily tailored so that the welding wire composition when melted will form an alloy defined by the weld deposit which substantially corresponds to the composition of the intermetallic alloy being joined. 4 figs.

  11. Texture Control by Selective Deformation Mechanism Activation in Magnesium Alloy

    E-Print Network [OSTI]

    Foley, David Christopher

    2014-07-01T23:59:59.000Z

    The need for high strength, light weight structures in automotive and aerospace applications has driven a resurgence of interest in magnesium and its alloys. Unlike aluminum, wrought magnesium typically has a high degree of mechanical anisotropy...

  12. Interdiffusivity in titanium-tantalum alloys processed at 1473 K

    E-Print Network [OSTI]

    Dibbern, Jennifer C

    2007-01-01T23:59:59.000Z

    Titanium-tantalum (Ti-Ta) alloys are likely to have a high biocompatibility and corrosion resistance that renders them novel materials of interest for biomedical applications[7, 14, 2]. With high strength and a low elastic ...

  13. Texture Control by Selective Deformation Mechanism Activation in Magnesium Alloy 

    E-Print Network [OSTI]

    Foley, David Christopher

    2014-07-01T23:59:59.000Z

    The need for high strength, light weight structures in automotive and aerospace applications has driven a resurgence of interest in magnesium and its alloys. Unlike aluminum, wrought magnesium typically has a high degree of mechanical anisotropy...

  14. Rigorous and General Definition of Thermodynamic Entropy

    E-Print Network [OSTI]

    Gian Paolo Beretta; Enzo Zanchini

    2010-10-05T23:59:59.000Z

    The physical foundations of a variety of emerging technologies --- ranging from the applications of quantum entanglement in quantum information to the applications of nonequilibrium bulk and interface phenomena in microfluidics, biology, materials science, energy engineering, etc. --- require understanding thermodynamic entropy beyond the equilibrium realm of its traditional definition. This paper presents a rigorous logical scheme that provides a generalized definition of entropy free of the usual unnecessary assumptions which constrain the theory to the equilibrium domain. The scheme is based on carefully worded operative definitions for all the fundamental concepts employed, including those of system, property, state, isolated system, environment, process, separable system, system uncorrelated from its environment, and parameters of a system. The treatment considers also systems with movable internal walls and/or semipermeable walls, with chemical reactions and/or external force fields, and with small numbers of particles. The definition of reversible process is revised by introducing the new concept of scenario. The definition of entropy involves neither the concept of heat nor that of quasistatic process; it applies to both equilibrium and nonequilibrium states. The role of correlations on the domain of definition and on the additivity of energy and entropy is discussed: it is proved that energy is defined and additive for all separable systems, while entropy is defined and additive only for separable systems uncorrelated from their environment; decorrelation entropy is defined. The definitions of energy and entropy are extended rigorously to open systems. Finally, to complete the discussion, the existence of the fundamental relation for stable equilibrium states is proved, in our context, for both closed and open systems.

  15. Maximum entropy principal for transportation

    SciTech Connect (OSTI)

    Bilich, F. [University of Brasilia (Brazil); Da Silva, R. [National Research Council (Brazil)

    2008-11-06T23:59:59.000Z

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  16. Manufacturing development of low activation vanadium alloys

    SciTech Connect (OSTI)

    Smith, J.P.; Johnson, W.R.; Baxi, C.B.

    1996-10-01T23:59:59.000Z

    General Atomics is developing manufacturing methods for vanadium alloys as part of a program to encourage the development of low activation alloys for fusion use. The culmination of the program is the fabrication and installation of a vanadium alloy structure in the DIII-D tokamak as part of the Radiative Divertor modification. Water-cooled vanadium alloy components will comprise a portion of the new upper divertor structure. The first step, procuring the material for this program has been completed. The largest heat of vanadium alloy made to date, 1200 kg of V-4Cr-4Ti, has been produced and is being converted into various product forms. Results of many tests on the material during the manufacturing process are reported. Research into potential fabrication methods has been and continues to be performed along with the assessment of manufacturing processes particularly in the area of joining. Joining of vanadium alloys has been identified as the most critical fabrication issue for their use in the Radiative Divertor Program. Joining processes under evaluation include resistance seam, electrodischarge (stud), friction and electron beam welding. Results of welding tests are reported. Metallography and mechanical tests are used to evaluate the weld samples. The need for a protective atmosphere during different welding processes is also being determined. General Atomics has also designed, manufactured, and will be testing a helium-cooled, high heat flux component to assess the use of helium cooled vanadium alloy components for advanced tokamak systems. The component is made from vanadium alloy tubing, machined to enhance the heat transfer characteristics, and joined to end flanges to allow connection to the helium supply. Results are reported.

  17. NITRIDATION EFFECTS ON THE OXIDATION MECHANISMS OF AN ODS FeAl INTERMETALLIC ALLOY

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    NITRIDATION EFFECTS ON THE OXIDATION MECHANISMS OF AN ODS FeAl INTERMETALLIC ALLOY F. Pedraza*, J-mail: fpedraza@univ-lr.fr Abstract An ODS FeAl intermetallic alloy has been nitrided at low-energy high flux of an ODS FeAl alloy have been discussed [13], indicating the formation of AlN and again of -Fe after

  18. Structural alloy with a protective coating containing silicon or silicon-oxide

    DOE Patents [OSTI]

    Natesan, K.

    1992-01-01T23:59:59.000Z

    This invention is comprised of an iron-based alloy containing chromium and optionally, nickel. The alloy has a surface barrier of silicon or silicon plus oxygen which converts at high temperature to a protective silicon compound. The alloy can be used in oxygen-sulfur mixed gases at temperatures up to about 1100{degrees}C.

  19. Hot-crack test for aluminium alloys welds using TIG process , F. Deschaux1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Hot-crack test for aluminium alloys welds using TIG process A. Niel1,a , F. Deschaux1 , C cracking in welds : state of art Aluminium alloys are highly sensitive to hot tearing phenomenon. It appears during solidification of the alloy, so it can be observed during welding, as well as during

  20. Aluminum battery alloys

    DOE Patents [OSTI]

    Thompson, David S. (Richmond, VA); Scott, Darwin H. (Mechanicsville, VA)

    1985-01-01T23:59:59.000Z

    Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  1. Aluminum battery alloys

    DOE Patents [OSTI]

    Thompson, D.S.; Scott, D.H.

    1984-09-28T23:59:59.000Z

    Aluminum alloys suitable for use as anode structures in electrochemical cells are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  2. Copper-tantalum alloy

    SciTech Connect (OSTI)

    Schmidt, Frederick A. (Ames, IA); Verhoeven, John D. (Ames, IA); Gibson, Edwin D. (Ames, IA)

    1986-07-15T23:59:59.000Z

    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  3. Neutron Absorbing Alloys

    DOE Patents [OSTI]

    Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

    2004-05-04T23:59:59.000Z

    The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

  4. Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion

    DOE Patents [OSTI]

    Steeves, Arthur F. (Schenectady, NY); Bibb, Albert E. (Clifton Park, NY)

    1984-01-01T23:59:59.000Z

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprising heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cool the alloy body, and heat the cooled body to a temperature between 1100.degree. to 1500.degree. F. for about 1 to 30 hours.

  5. High strain in polycrystalline Ni{sub 48.8}Mn{sub 31.4}Ga{sub 19.8} Heusler alloys under overlapped static and oscillating magnetic fields

    SciTech Connect (OSTI)

    Montanher, D. Z.; Pereira, J. R. D.; Cótica, L. F.; Santos, I. A. [Department of Physics, State University of Maringá, Av. Colombo 5790, Maringá - PR 87020-900 (Brazil); Gotardo, R. A. M. [Technological Federal University of Paraná, Av. Alberto Carazzai 1640, Cornélio Procópio - PR 86300-000 (Brazil); Viana, D. S. F.; Garcia, D.; Eiras, J. A. [Department of Physics, Federal University of São Carlos, Rod. Washington Luiz, Km 235, São Carlos - SP 13565-905 (Brazil)

    2014-09-21T23:59:59.000Z

    Martensitic polycrystalline Ni{sub 48.8}Mn{sub 31.4}Ga{sub 19.8} Heusler alloys, with a stacking period of 14 atomic planes at room temperature, were innovatively processed by combining high-energy ball milling and powder metallurgy. Bulk samples were mechanically coupled to a piezoelectric material in a parallel configuration, and the mechanical deformation of the studied system due to the twin's variant motion was investigated under overlapped static and oscillating magnetic fields. A reversible and high mechanical deformation is observed when the frequency of the oscillating magnetic field is tuned with the natural vibration frequency of this system. In this condition, a linear deformation as a function of the static magnetic field amplitude occurs in the ±4 kOe range, and a mechanical deformation of 2% at 10 kOe is observed.

  6. Entanglement entropy on the fuzzy sphere

    E-Print Network [OSTI]

    Karczmarek, Joanna L

    2013-01-01T23:59:59.000Z

    We obtain entanglement entropy on the noncommutative (fuzzy) two-sphere. To define a subregion with a well defined boundary in this geometry, we use the symbol map between elements of the noncommutative algebra and functions on the sphere. We find that entanglement entropy is not proportional to the length of the region's boundary. Rather, in agreement with holographic predictions, it is extensive for regions whose area is a small (but fixed) fraction of the total area of the sphere. This is true even in the limit of small noncommutativity. We also find that entanglement entropy grows linearly with N, where N is the size of the irreducible representation of SU(2) used to define the fuzzy sphere.

  7. Gacs quantum algorithmic entropy in infinite dimensional Hilbert spaces

    SciTech Connect (OSTI)

    Benatti, Fabio, E-mail: benatti@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, I-34151 Trieste (Italy); Oskouei, Samad Khabbazi, E-mail: kh.oskuei@ut.ac.ir; Deh Abad, Ahmad Shafiei, E-mail: shafiei@khayam.ut.ac.ir [Department of Mathematics, School of Mathematics, Statistics and Computer Science, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-08-15T23:59:59.000Z

    We extend the notion of Gacs quantum algorithmic entropy, originally formulated for finitely many qubits, to infinite dimensional quantum spin chains and investigate the relation of this extension with two quantum dynamical entropies that have been proposed in recent years.

  8. From finite-system entropy to entropy rate for a Hidden Markov Process

    E-Print Network [OSTI]

    Or Zuk; Eytan Domany; Ido Kanter; Michael Aizenman

    2005-10-06T23:59:59.000Z

    A recent result presented the expansion for the entropy rate of a Hidden Markov Process (HMP) as a power series in the noise variable $\\eps$. The coefficients of the expansion around the noiseless ($\\eps = 0$) limit were calculated up to 11th order, using a conjecture that relates the entropy rate of a HMP to the entropy of a process of finite length (which is calculated analytically). In this communication we generalize and prove the validity of the conjecture, and discuss the theoretical and practical consequences of our new theorem.

  9. A Data Streaming Algorithm for Estimating Entropies of OD Flows

    E-Print Network [OSTI]

    Greenberg, Albert

    A Data Streaming Algorithm for Estimating Entropies of OD Flows Ashwin Lall, Mitsu Ogihara s i ai log (ai) = log 8 - 12 8 = 1.5 Chuck Zhao IMC 2007, San Diego, CA 1 #12;OD Flow Entropy · An OD the empirical entropies of all OD flows in an ISP network. · We need to measure ­ the entropy norm i ai log (ai

  10. A Note on Black Hole Temperature and Entropy

    E-Print Network [OSTI]

    P. R. Silva

    2006-05-09T23:59:59.000Z

    We propose intuitive derivations of the Hawking temperature and the Bekenstein-Hawking entropy of a Schwarzschild black hole.

  11. Entropy of charged dilaton-axion black hole

    E-Print Network [OSTI]

    Tanwi Ghosh; Soumitra SenGupta

    2008-06-06T23:59:59.000Z

    Using brick wall method the entropy of charged dilaton-axion black hole is determined for both asymptotically flat and non-flat cases. The entropy turns out to be proportional to the horizon area of the black hole confirming the Beckenstien, Hawking area-entropy formula for black holes. The leading order logarithmic corrections to the entropy are also derived for such black holes.

  12. Magnetocaloric effect in as-cast Gd{sub 1?x}Y{sub x} alloys with x?=?0.0, 0.1, 0.2, 0.3, 0.4

    SciTech Connect (OSTI)

    Lara Pérez, E. S.; Hernández Paz, J. F.; Elizalde Galindo, J. T., E-mail: jose.elizalde@uacj.mx [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro 450 norte, 32310 Ciudad Juárez, Chihuahua (Mexico); Betancourt, I. [Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico); Matutes Aquino, J. A. [Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, 31109 Chihuahua (Mexico)

    2014-05-07T23:59:59.000Z

    In this report, we present the magnetocaloric effect of Gd{sub 1?x}Y{sub x} alloys (0.0???×???0.4) prepared by arc-melting from high purity Gd and Y precursors in inert atmosphere. The formation of Gd{sub 1?x}Y{sub x} solid solutions was verified by means of X-ray diffraction analysis across the compositional series; also, residual secondary phases Gd and Y were present. Magnetic characterization performed by Vibrating Sample Magnetometry at a maximum applied field of 3.0?T showed a drastic reduction of the magnetization saturation (from 233?emu/g for x?=?0.0 to 183?emu/g for x?=?0.4), due to a dilution effect of the Y alloying, together with a marked Curie temperature decrease from 296?K to 196?K between x?=?0.0 and x?=?0.4. The second-order character of the magnetic transition was established by Arrot plots for all the cases. On the other hand, the magnetic entropy variation, determined from numerical integration of Maxwell relation displayed excellent values above 5.30?J/kg K for alloys with x?

  13. GMM Estimation of a Maximum Entropy Distribution with Interval Data

    E-Print Network [OSTI]

    Perloff, Jeffrey M.

    GMM Estimation of a Maximum Entropy Distribution with Interval Data Ximing Wu* and Jeffrey M estimate it using a simple yet flexible maximum entropy density. Our Monte Carlo simulations show that the proposed maximum entropy density is able to approximate various distributions extremely well. The two

  14. university-logo Convex entropy, Hopf bifurcation, and viscous and

    E-Print Network [OSTI]

    Zumbrun, Kevin

    university-logo Convex entropy, Hopf bifurcation, and viscous and inviscid shock stability KevinXiv) Zumbrun Convex Entropy #12;university-logo I. Introduction: Viscous and inviscid shock waves Quasilinear, Stationary solutions of ut - ux + f (u)x = (b(u)ux )x . Zumbrun Convex Entropy #12;university-logo Stability

  15. Entropy and multifractal analysis of multiplicity distributions from pp simulated events up to LHC energies

    E-Print Network [OSTI]

    M. K. Suleymanov; M. Sumbera; I. Zborovsky

    2003-04-22T23:59:59.000Z

    Using three different Monte Carlo generators of high energy proton-proton collisions (HIJING, NEXUS, and PSM) we study the energy dependence of multiplicity distributions of charged particles including the LHC energy range. Results are used for calculation of the information entropy, Renyi's dimensions and other multifractal characteristics of particle production.

  16. Quantifying the Entropy of Binding for Water Molecules in Protein Cavities by Computing Correlations

    E-Print Network [OSTI]

    Huggins, David J.

    2014-12-17T23:59:59.000Z

    . 71:670–681. 8. Yu, H., and S. W. Rick. 2010. Free energy, entropy, and enthalpy of a water molecule in various protein environments. J. Phys. Chem. B. 114:11552–11560.REFERENCESAcknowledgments go to the Cambridge High Performance Computing Ser- vice...

  17. Measurement of Renyi entropies in multiparticle production: a DO-LIST II

    E-Print Network [OSTI]

    A. Bialas; W. Czyz; K. Zalewski

    2006-10-30T23:59:59.000Z

    Recently suggested method of measuring Renyi entropies of multiparticle systems produced in high-energy collisions is presented in the form of a "do-list", explaining explicitely how to perform the measurement and suggesting improvements in the treatment of the data.

  18. Viscosity to entropy ratio at extremality

    E-Print Network [OSTI]

    Sayan K. Chakrabarti; Sachin Jain; Sudipta Mukherji

    2010-01-19T23:59:59.000Z

    Assuming gauge theory realization at the boundary, we show that the viscosity to entropy ratio is 1/(4 pi) where the bulk is represented by a large class of extremal black holes in anti-de Sitter space. In particular, this class includes multiple R-charged black holes in various dimensions.

  19. Quantum Entropy of Charged Rotating Black Holes

    E-Print Network [OSTI]

    R. B. Mann

    1996-07-10T23:59:59.000Z

    I discuss a method for obtaining the one-loop quantum corrections to the tree-level entropy for a charged Kerr black hole. Divergences which appear can be removed by renormalization of couplings in the tree-level gravitational action in a manner similar to that for a static black hole.

  20. General Database Statistics Using Entropy Maximization

    E-Print Network [OSTI]

    Suciu, Dan

    (z) Estimate: q(y) :- R(x, y), S(y, z) Fig. 1. An example of a Statistical Program and a query, q whoseGeneral Database Statistics Using Entropy Maximization Raghav Kaushik1 , Christopher R´e2 , and Dan engines. The key object of our study is a statistical program, which is a set of pairs (v, d), where v

  1. Integrating Correlated Bayesian Networks Using Maximum Entropy

    SciTech Connect (OSTI)

    Jarman, Kenneth D.; Whitney, Paul D.

    2011-08-30T23:59:59.000Z

    We consider the problem of generating a joint distribution for a pair of Bayesian networks that preserves the multivariate marginal distribution of each network and satisfies prescribed correlation between pairs of nodes taken from both networks. We derive the maximum entropy distribution for any pair of multivariate random vectors and prescribed correlations and demonstrate numerical results for an example integration of Bayesian networks.

  2. Subtyping in alloy

    E-Print Network [OSTI]

    Torlak, Emina, 1979-

    2004-01-01T23:59:59.000Z

    A type system for the Alloy modelling language is described that supports subtypes and allows overloading of relation names. No special syntactic features needed to be added to the language to support the type system; there ...

  3. Preparations of rare earth-iron alloys by thermite reduction

    DOE Patents [OSTI]

    Schmidt, F.A.; Peterson, D.T.; Wheelock, J.T.

    1985-10-28T23:59:59.000Z

    Disclosed is an improved method for the preparation of high-purity rare earth-iron alloys by the aluminothermic reduction of a mixture of rare earth and iron fluorides.

  4. alloys by properties: Topics by E-print Network

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

    ALLOYED STEEL X20 CiteSeer Summary: In this paper, the effect of service temperature and life on high-cycle fatigue properties of base metal, steel X20 CrMoV 12-1, has been...

  5. Modeling of the Thermal Field in Dissimilar Alloy Ultrasonic Welding

    E-Print Network [OSTI]

    Jedrasiak, P.; Shercliff, H. R.; Chen, Y. C.; Wang, L.; Prangnell, P.; Robson, J.

    2014-12-10T23:59:59.000Z

    This paper describes a finite element model for predicting the temperature field in high power ultrasonic welding aluminum AA6111 to two dissimilar alloys, magnesium AZ31, and low carbon steel DC04. Experimental thermocouple and other evidence...

  6. alloy aiming applications: Topics by E-print Network

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

    Olivier Jean 2002-01-01 2 Rapid Quenching of Liquid Lead Base Alloys for High Performance Storage Battery Applications CiteSeer Summary: Abstract The aim of this study was to...

  7. aa2219 aluminium alloy: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  8. aluminium base alloys: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 6 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  9. aa5052 aluminium alloy: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  10. aluminium alloy aa6056: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  11. aluminium foundry alloys: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  12. alloy steel standard: Topics by E-print Network

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

    18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Estimation of Atmospheric Corrosion of High-Strength, Low-Alloy Steels Engineering Websites Summary: Estimation of...

  13. Degassing of molten alloys with the assistance of ultrasonic vibration

    DOE Patents [OSTI]

    Han, Qingyou (Knoxville, TN); Xu, Hanbing (Knoxville, TN); Meek, Thomas T. (Knoxville, TN)

    2010-03-23T23:59:59.000Z

    An apparatus and method are disclosed in which ultrasonic vibration is used to assist the degassing of molten metals or metal alloys thereby reducing gas content in the molten metals or alloys. High-intensity ultrasonic vibration is applied to a radiator that creates cavitation bubbles, induces acoustic streaming in the melt, and breaks up purge gas (e.g., argon or nitrogen) which is intentionally introduced in a small amount into the melt in order to collect the cavitation bubbles and to make the cavitation bubbles survive in the melt. The molten metal or alloy in one version of the invention is an aluminum alloy. The ultrasonic vibrations create cavitation bubbles and break up the large purge gas bubbles into small bubbles and disperse the bubbles in the molten metal or alloy more uniformly, resulting in a fast and clean degassing.

  14. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

    Anderson, Iver E; Terpstra, Robert L

    2014-10-21T23:59:59.000Z

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. Bodies made from the dispersion strengthened solidified particles exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures.

  15. Alumina-forming Austenitic Alloys for Advanced Recuperators

    SciTech Connect (OSTI)

    Pint, Bruce A [ORNL; Shingledecker, John P [ORNL; Brady, Michael P [ORNL; Maziasz, Philip J [ORNL

    2007-01-01T23:59:59.000Z

    Materials selection for thin-walled recuperators has been extensively investigated over the past decade. In the latest generation of recuperated turbine engines, type 347 stainless steel has been replaced by higher alloyed steels and Ni-base chromia-forming alloys. However, high (linear) rates of chromia evaporation in exhaust gas fundamentally limits the oxidation lifetime of these chromia-forming alloys. One solution is to use alumina-forming alloys that are more resistant to this environment. The lower scale growth kinetics and resistance to evaporation in the presence of water vapor suggests an order of magnitude increase in lifetime for alumina-forming alloys. A significant problem with this strategy was the large drop in creep strength with the addition of sufficient Al to form an external alumina scale. However, new Fe-base austenitic compositions have been developed with sufficient strength for this application above 700 C.

  16. Microstructures and oxidation behavior of some Molybdenum based alloys

    SciTech Connect (OSTI)

    Ray, Pratik Kumar

    2010-12-15T23:59:59.000Z

    The advent of Ni based superalloys revolutionized the high temperature alloy industry. These materials are capable of operating in extremely harsh environments, comprising of temperatures around 1050 C, under oxidative conditions. Demands for increased fuel efficiency, however, has highlighted the need for materials that can be used under oxidative conditions at temperatures in excess of 1200 C. The Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that melt in the 1250 - 1450 C, resulting in softening of the alloys above 1000 C. Therefore, recent research directions have been skewed towards exploring and developing newer alloy systems. This thesis comprises a part of such an effort. Techniques for rapid thermodynamic assessments were developed and applied to two different systems - Mo-Si alloys with transition metal substitutions (and this forms the first part of the thesis) and Ni-Al alloys with added components for providing high temperature strength and ductility. A hierarchical approach towards alloy design indicated the Mo-Ni-Al system as a prospective candidate for high temperature applications. Investigations on microstructures and oxidation behavior, under both isothermal and cyclic conditions, of these alloys constitute the second part of this thesis. It was seen that refractory metal systems show a marked microstructure dependence of oxidation.

  17. Nonextensive entropy approach to space plasma fluctuations and turbulence

    E-Print Network [OSTI]

    M. P. Leubner; Z. Voros; W. Baumjohann

    2006-05-22T23:59:59.000Z

    Spatial intermittency in fully developed turbulence is an established feature of astrophysical plasma fluctuations and in particular apparent in the interplanetary medium by in situ observations. In this situation the classical Boltzmann-Gibbs extensive thermo-statistics, applicable when microscopic interactions and memory are short ranged, fails. Upon generalization of the entropy function to nonextensivity, accounting for long-range interactions and thus for correlations in the system, it is demonstrated that the corresponding probability distributions (PDFs) are members of a family of specific power-law distributions. In particular, the resulting theoretical bi-kappa functional reproduces accurately the observed global leptokurtic, non-Gaussian shape of the increment PDFs of characteristic solar wind variables on all scales. Gradual decoupling is obtained by enhancing the spatial separation scale corresponding to increasing kappa-values in case of slow solar wind conditions where a Gaussian is approached in the limit of large scales. Contrary, the scaling properties in the high speed solar wind are predominantly governed by the mean energy or variance of the distribution. The PDFs of solar wind scalar field differences are computed from WIND and ACE data for different time-lags and bulk speeds and analyzed within the nonextensive theory. Consequently, nonlocality in fluctuations, related to both, turbulence and its large scale driving, should be related to long-range interactions in the context of nonextensive entropy generalization, providing fundamentally the physical background of the observed scale dependence of fluctuations in intermittent space plasmas.

  18. Development of Combinatorial Methods for Alloy Design and Optimization

    SciTech Connect (OSTI)

    Pharr, George M.; George, Easo P.; Santella, Michael L

    2005-07-01T23:59:59.000Z

    The primary goal of this research was to develop a comprehensive methodology for designing and optimizing metallic alloys by combinatorial principles. Because conventional techniques for alloy preparation are unavoidably restrictive in the range of alloy composition that can be examined, combinatorial methods promise to significantly reduce the time, energy, and expense needed for alloy design. Combinatorial methods can be developed not only to optimize existing alloys, but to explore and develop new ones as well. The scientific approach involved fabricating an alloy specimen with a continuous distribution of binary and ternary alloy compositions across its surface--an ''alloy library''--and then using spatially resolved probing techniques to characterize its structure, composition, and relevant properties. The three specific objectives of the project were: (1) to devise means by which simple test specimens with a library of alloy compositions spanning the range interest can be produced; (2) to assess how well the properties of the combinatorial specimen reproduce those of the conventionally processed alloys; and (3) to devise screening tools which can be used to rapidly assess the important properties of the alloys. As proof of principle, the methodology was applied to the Fe-Ni-Cr ternary alloy system that constitutes many commercially important materials such as stainless steels and the H-series and C-series heat and corrosion resistant casting alloys. Three different techniques were developed for making alloy libraries: (1) vapor deposition of discrete thin films on an appropriate substrate and then alloying them together by solid-state diffusion; (2) co-deposition of the alloying elements from three separate magnetron sputtering sources onto an inert substrate; and (3) localized melting of thin films with a focused electron-beam welding system. Each of the techniques was found to have its own advantages and disadvantages. A new and very powerful technique for rapid structural and chemical characterization of alloy libraries was developed based on high intensity x-radiation available at synchrotron sources such as the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). With the technique, structural and chemical characterization of up to 2500 discrete positions on a library can made in a period of less than 4 hours. Among the parameters that can be measured are the chemical composition, crystal structure, lattice parameters, texture, and grain size. From these, one can also deduce isothermal sections of ternary phase diagrams. The equipment and techniques needed to do this are now in place for use in future combinatorial studies at the ORNL beam line at the APS. In conjunction with the chemical and structural investigations, nanoindentation techniques were developed to investigate the mechanical properties of the combinatorial libraries. The two primary mechanical properties of interest were the elastic modulus, E, and hardness, H, both of which were measured on alloy library surfaces with spatial resolutions of better than 1 m. A nanoindentation testing system at ORNL was programmed to make a series of indentations at specified locations on the library surface and automatically collect and store all the data needed to obtain hardness and modulus as a function of position. Approximately 200 indentations can be made during an overnight run, which allows for mechanical property measurement over a wide range of chemical composition in a relatively short time. Since the materials based on the Fe-Ni-Cr system often find application in highly carburizing and harsh chemical environments, simple techniques were developed to assess the resistance of Fe-Ni-Cr alloy libraries to carburization and corrosion. Alloy libraries were carburized by standard techniques, and the effectiveness of the carburization at various points along the sample surface was assessed by nanoindentation hardness measurement. Corrosion tests were conducted by placing library specimens in highly corrosive aqueous environments, with the corr

  19. Oxidation, carburization and/or sulfidation resistant iron aluminide alloy

    DOE Patents [OSTI]

    Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier S.; Hajaligol, Mohammad R.; Lilly, Jr., A. Clifton

    2003-08-19T23:59:59.000Z

    The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, .ltoreq.1% Cr and either .gtoreq.0.05% Zr or Zro.sub.2 stringers extending perpendicular to an exposed surface of the heating element or .gtoreq.0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B. .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, .ltoreq.1% oxygen, .ltoreq.3% Cu, balance Fe.

  20. Stellar mixing length theory with entropy rain

    E-Print Network [OSTI]

    Brandenburg, Axel

    2015-01-01T23:59:59.000Z

    Stellar mixing length theory is modified to include the effects of a nongradient term that originates from the motion of convective elements with entropy perturbations of either sign. It is argued that such a term, first studied by Deardorff in the meteorological context, represents the effects of thin intense downdrafts caused by the rapid cooling in the granulation layer at the top of the convection zone. They transport heat nonlocally, as originally anticipated by Spruit in the 1990s, who describes the convection in the strongly stratified simulations of Stein & Nordlund as entropy rain. Although our model has ill-determined free parameters, it demonstrates that solutions can be found that look similar to the original ones, except that the deeper layers are now Schwarzschild stable, so no giant cells are produced and the typical convective scale is that of granules even at larger depth. Consequences for modeling solar differential, the global dynamo, and sunspots are briefly discussed.

  1. Nonsingular Decaying Vacuum Cosmology and Entropy Production

    E-Print Network [OSTI]

    J. A. S. Lima; S. Basilakos; Joan Solà

    2015-03-08T23:59:59.000Z

    The thermodynamic behavior of a decaying vacuum cosmology describing the entire cosmological history evolving between two extreme (early and late time) de Sitter eras is investigated. The thermal evolution from the early de Sitter to the radiation phase is discussed in detail. The temperature evolution law and the increasing entropy function are analytically determined. The entropy of the effectively massless particles is initially zero but evolves continuously to the present day maximum value within the current Hubble radius, $S_0 \\sim 10^{88}$ in natural units. By using the Gibbons-Hawking temperature relation for the de Sitter spacetime, it is found that the ratio between the primeval and the late time vacuum energy densities is $\\rho_{vI}/\\rho_{v0} \\sim 10^{123}$, as required by some naive estimates from quantum field theory.

  2. Effect of oxide films on hydrogen permeability of candidate Stirling heater head tube alloys

    SciTech Connect (OSTI)

    Schuon, S R; Misencik, J A

    1981-01-01T23:59:59.000Z

    High pressure hydrogen has been selected as the working fluid for the developmental automotive Stirling engine. Containment of the working fluid during operation of the engine at high temperatures and at high hydrogen gas pressures is essential for the acceptance of the Stirling engine as an alternative to the internal combustion engine. Most commercial alloys are extremely permeable to pure hydrogen at high temperatures. A program was undertaken at NASA Lewis Research Center (LeRC) to reduce hydrogen permeability in the Stirling engine heater head tubes by doping the hydrogen working fluid with CO or CO/sub 2/. Small additions of these gases were shown to form an oxide on the inside tube wall and thus reduce hydrogen permeability. A study of the effects of dopant concentration, alloy composition, and effects of surface oxides on hydrogen permeability in candidate heater head tube alloys is summarized. Results showed that hydrogen permeability was similar for iron-base alloys (N-155, A286, IN800, 19-9DL, and Nitronic 40), cobalt-base alloys (HS-188) and nickel-base alloys (IN718). In general, the permeability of the alloys decreased with increasing concentration of CO or CO/sub 2/ dopant, with increasing oxide thickness, and decreasing oxide porosity. At high levels of dopants, highly permeable liquid oxides formed on those alloys with greater than 50% Fe content. Furthermore, highly reactive minor alloying elements (Ti, Al, Nb, and La) had a strong influence on reducing hydrogen permeability.

  3. QCD Level Density from Maximum Entropy Method

    E-Print Network [OSTI]

    Shinji Ejiri; Tetsuo Hatsuda

    2005-09-24T23:59:59.000Z

    We propose a method to calculate the QCD level density directly from the thermodynamic quantities obtained by lattice QCD simulations with the use of the maximum entropy method (MEM). Understanding QCD thermodynamics from QCD spectral properties has its own importance. Also it has a close connection to phenomenological analyses of the lattice data as well as experimental data on the basis of hadronic resonances. Our feasibility study shows that the MEM can provide a useful tool to study QCD level density.

  4. Variation of Entanglement Entropy in Scattering Process

    E-Print Network [OSTI]

    I. Y. Park; Shigenori Seki; Sang-Jin Sin

    2015-01-09T23:59:59.000Z

    In a scattering process, the final state is determined by an initial state and an S-matrix. We focus on two-particle scattering processes and consider the entanglement between these particles. For two types initial states; i.e., an unentangled state and an entangled one, we calculate perturbatively the change of entanglement entropy from the initial state to the final one. Then we show a few examples in a field theory and in quantum mechanics.

  5. Bulk viscous cosmology: statefinder and entropy

    E-Print Network [OSTI]

    M. Hu; Xin He Meng

    2005-11-23T23:59:59.000Z

    The statefinder diagnostic pair is adopted to differentiate viscous cosmology models and it is found that the trajectories of these viscous cosmology models on the statefinder pair $s-r$ plane are quite different from those of the corresponding non-viscous cases. Particularly for the quiessence model, the singular properties of state parameter $w=-1$ are obviously demonstrated on the statefinder diagnostic pair planes. We then discuss the entropy of the viscous / dissipative cosmology system which may be more practical to describe the present cosmic observations as the perfect fluid is just a global approximation to the complicated cosmic media in current universe evolution. When the bulk viscosity takes the form of $\\zeta=\\zeta_{1}\\dot{a}/a$($\\zeta_{1}$ is constant), the relationship between the entropy $S$ and the redshift $z$ is explicitly given out. We find that the entropy of the viscous cosmology is always increasing and consistent with the thermodynamics arrow of time for the universe evolution. With the parameter constraints from fitting to the 157 gold data of supernova observations, it is demonstrated that this viscous cosmology model is rather well consistent to the observational data at the lower redshifts, and together with the diagnostic statefinder pair analysis it is concluded that the viscous cosmic models tend to the favored $\\Lambda$CDM model in the later cosmic evolution, agreeable to lots of cosmological simulation results, especially to the fact of confidently observed current accelerating cosmic expansion.

  6. Perturbative entanglement entropy in nonlocal theories

    E-Print Network [OSTI]

    Rabideau, Charles

    2015-01-01T23:59:59.000Z

    Entanglement entropy in the vacuum state of local field theories exhibits an area law. However, nonlocal theories at large N and strong coupling violate this area law. In these theories, the leading divergence in the entanglement entropy is extensive for regions smaller than the effective nonlocality scale and proportional to this effective nonlocality scale for regions larger than it. This raises the question: is a volume law a generic feature of nonlocal theories, or is it only present at strong coupling and large N? This paper investigates entanglement entropy of large regions in weakly coupled nonlocal theories, to leading order in the coupling. The two theories studied are phi^4 theory on the noncommutative plane and phi^4 theory with a dipole type nonlocal modification using a fixed nonlocality scale. Both theories are found to follow an area law to first order in the coupling, hence no evidence is found for a volume law. This indicates that, perturbatively the nonlocal interactions considered are not g...

  7. De-alloyed platinum nanoparticles

    DOE Patents [OSTI]

    Strasser, Peter (Houston, TX); Koh, Shirlaine (Houston, TX); Mani, Prasanna (Houston, TX); Ratndeep, Srivastava (Houston, TX)

    2011-08-09T23:59:59.000Z

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  8. Report on Characterization of U-10 wt.% Zr Alloy

    SciTech Connect (OSTI)

    McKeown, J; Wall, M; Hsiung, L; Turchi, P

    2012-03-01T23:59:59.000Z

    This report summarizes the chemical and structural characterization results for a U-10 wt.% Zr alloy to be used in an ultra-high burn-up nuclear fuel concept. The as-cast alloy material was received from Texas A and M University. Characterization and an initial heat treatment of the alloy material were conducted at Lawrence Livermore National Laboratory. The as-received ingot was sectioned for X-ray analysis, metallography, SEM, TEM, and heat treatments, as shown in Figure 1.

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

    DOE Patents [OSTI]

    Natesan, K.; Baxter, D.J.

    1983-07-26T23:59:59.000Z

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

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

    DOE Patents [OSTI]

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

    1984-01-01T23:59:59.000Z

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

  11. Microstructural examination of commercial ferritic alloys at 299 DPA

    SciTech Connect (OSTI)

    Gelles, D.S.

    1995-11-01T23:59:59.000Z

    Microstructures and density change measurements are reported for Martensitic commercial steels HT-9 and Modified 9Cr-lMo (T9) and oxide dispersion strengthened ferritic alloys MA956 and NU957 following irradiation in the FFTF/MOTA at 420{degrees}C to 200 DPA. Swelling as determined by density change remains below 2% for all conditions. Microstructures are found to be stable except in recrystallized grains of MA957, which are fabrication artifacts, with only minor swelling in the Martensitic steels and {alpha}{prime} precipitation in alloys with 12% or more chromium. These results further demonstrate the high swelling resistance and microstructural stability of the ferritic alloy class.

  12. Microstructural examination of commercial ferritic alloys at 200 dpa

    SciTech Connect (OSTI)

    Gelles, D.S. [Pacific Northwest Lab., Richland, WA (United States)

    1994-09-01T23:59:59.000Z

    Microstructures and density change measurements are reported for Martensitic commercial steels HT-9 and Modified 9Cr-1Mo (T9) and oxide dispersion strengthened ferritic alloys MA956 and MA957 following irradiation in the FFTF/MOTA at 420{degrees}C to 200 DPA. Swelling as determined by density change remains below 2% for all conditions. Microstructures are found to be stable except in recrystallized grains of MA957, which are fabrication artifacts, with only minor swelling in the Martensitic steels and {alpha}{prime} precipitation in alloys with 12% or more chromium. These results further demonstrate the high swelling resistance and microstructural stability of the ferritic alloy class.

  13. On generalized gravitational entropy, squashed cones and holography

    E-Print Network [OSTI]

    Arpan Bhattacharyya; Menika Sharma; Aninda Sinha

    2013-12-13T23:59:59.000Z

    We consider generalized gravitational entropy in various higher derivative theories of gravity dual to four dimensional CFTs using the recently proposed regularization of squashed cones. We derive the universal terms in the entanglement entropy for spherical and cylindrical surfaces. This is achieved by constructing the Fefferman-Graham expansion for the leading order metrics for the bulk geometry and evaluating the generalized gravitational entropy. We further show that the Wald entropy evaluated in the bulk geometry constructed for the regularized squashed cones leads to the correct universal parts of the entanglement entropy for both spherical and cylindrical entangling surfaces. We comment on the relation with the Iyer-Wald formula for dynamical horizons relating entropy to a Noether charge. Finally we show how to derive the entangling surface equation in Gauss-Bonnet holography.

  14. Entropy and Area of Black Holes in Loop Quantum Gravity

    E-Print Network [OSTI]

    I. B. Khriplovich

    2002-03-31T23:59:59.000Z

    Simple arguments related to the entropy of black holes strongly constrain the spectrum of the area operator for a Schwarzschild black hole in loop quantum gravity. In particular, this spectrum is fixed completely by the assumption that the black hole entropy is maximum. Within the approach discussed, one arrives in loop quantum gravity at a quantization rule with integer quantum numbers $n$ for the entropy and area of a black hole.

  15. Occam's Razor Cuts Away the Maximum Entropy Principle

    E-Print Network [OSTI]

    Rudnicki, ?ukasz

    2014-01-01T23:59:59.000Z

    I show that the maximum entropy principle can be replaced by a more natural assumption, that there exists a phenomenological function of entropy consistent with the microscopic model. The requirement of existence provides then a unique construction of the related probability density. I conclude the letter with an axiomatic formulation of the notion of entropy, which is suitable for exploration of the non-equilibrium phenomena.

  16. Multi-range force sensors utilizing shape memory alloys

    DOE Patents [OSTI]

    Varma, Venugopal K. (Knoxville, TN)

    2003-04-15T23:59:59.000Z

    The present invention provides a multi-range force sensor comprising a load cell made of a shape memory alloy, a strain sensing system, a temperature modulating system, and a temperature monitoring system. The ability of the force sensor to measure contact forces in multiple ranges is effected by the change in temperature of the shape memory alloy. The heating and cooling system functions to place the shape memory alloy of the load cell in either a low temperature, low strength phase for measuring small contact forces, or a high temperature, high strength phase for measuring large contact forces. Once the load cell is in the desired phase, the strain sensing system is utilized to obtain the applied contact force. The temperature monitoring system is utilized to ensure that the shape memory alloy is in one phase or the other.

  17. Temporal Entropy Generation in the Viscous Layers of Laterally-converging Duct Flows

    SciTech Connect (OSTI)

    Donald M. McEligot; Robert S. Brodkey; Helmut Eckelmann

    2008-12-01T23:59:59.000Z

    Since insight into entropy generation is a key to increasing efficiency and thereby reducing fuel consumption and/or waste and -- for wall-bounded flows -- most entropy is generated in the viscous layer, we examine the transient behavior of its dominant contributor there for a non-canonical flow. New measurements in oil flow are presented for the effects of favorable streamwise mean pressure gradients on temporal entropy generation rates and, in the process, on key Reynolds-stress-producing events such as sweep front passage and on the deceleration/outflow phase of the overall bursting process. Two extremes have been considered: (1) a high pressure gradient, nearing "laminarization," and (2), for comparison, a low pressure gradient corresponding to many earlier experiments. In both cases, the peak temporal entropy generation rate occurs shortly after passage of the ejection/sweep interface. Whether sweep and ejection rates appear to decrease or increase with the pressure gradient depends on the feature examined and the manner of sampling. When compared using wall coordinates for velocities, distances and time, the trends and magnitudes of the transient behaviors are mostly the same. The main effects of the higher pressure gradient are (1) changes in the time lag between detections -- representing modification of the shape of the sweep front and the sweep angle with the wall, (2) modification of the magnitude of an instantaneous Reynolds shear stress with wall distance and (3) enlarging the sweeps and ejections. Results new for both low and high pressure gradients are the temporal behaviors of the dominant contribution to entropy generation; it is found to be much more sensitive to distance from the wall than to streamwise pressure gradient.

  18. The transported entropies of ions in solid state fluorides and beta-alumina

    SciTech Connect (OSTI)

    Sharivker, V.S.; Ratkje, S.K. [Univ. of Trondheim (Norway)

    1996-10-01T23:59:59.000Z

    The technical relevance of reversible heat effects is discussed with reference to high temperature batteries and electrolysis systems. The transported entropies of Na{sup +} in solid state mixtures of NaF and Na{sub 3}AlF{sub 6} are presented. The transported entropies are S{sup *cry}{sub Na{sup +}} = 140 {+-} 7 J K{sup {minus}1} mol{sup {minus}1} for cryolite, S{sup *NaF}{sub Na{sup +}} = 81 {+-} 8 J K{sup {minus}1} mol{sup {minus}1} for sodium fluoride and S{sup *{beta}}{sub Na{sup +}} = 60 {+-} 5 J K{sup {minus}1} mol{sup {minus}1} for sodium {beta}{double_prime}-alumina at the temperature range 380--500 C. The value obtained for sodium in the solid cryolite is higher than transported entropy of Na{sup +} in other solid sodium conductors and makes the authors predict that the transported entropy for Na{sup +} in the molten electrolyte mixture for aluminum production is substantial, and that so are the reversible heat effects in the aluminum electrolysis cell.

  19. Conformal perturbation theory and higher spin entanglement entropy on the torus

    E-Print Network [OSTI]

    Shouvik Datta; Justin R. David; S. Prem Kumar

    2014-12-12T23:59:59.000Z

    We study the free fermion theory in 1+1 dimensions deformed by chemical potentials for holomorphic, conserved currents at finite temperature and on a spatial circle. For a spin-three chemical potential \\mu, the deformation is related at high temperatures to a higher spin black hole in hs[0] theory on AdS_3 spacetime. We calculate the order \\mu^2 corrections to the single interval Renyi and entanglement entropies on the torus using the bosonized formulation. A consistent result, satisfying all checks, emerges upon carefully accounting for both perturbative and winding mode contributions in the bosonized language. The order \\mu^2 corrections involve integrals that are finite but potentially sensitive to contact term singularities. We propose and apply a prescription for defining such integrals which matches the Hamiltonian picture and passes several non-trivial checks for both thermal corrections and the Renyi entropies at this order. The thermal corrections are given by a weight six quasi-modular form, whilst the Renyi entropies are controlled by quasi-elliptic functions of the interval length with modular weight six. We also point out the well known connection between the perturbative expansion of the partition function in powers of the spin-three chemical potential and the Gross-Taylor genus expansion of large-N Yang-Mills theory on the torus. We note the absence of winding mode contributions in this connection, which suggests qualitatively different entanglement entropies for the two systems.

  20. Osmosis, colligative properties, entropy, free energy and the chemical potential

    E-Print Network [OSTI]

    Peter Hugo Nelson

    2014-09-13T23:59:59.000Z

    A diffusive model of osmosis is presented that explains currently available experimental data. It makes predictions that distinguish it from the traditional convective flow model of osmosis, some of which have already been confirmed experimentally and others have yet to be tested. It also provides a simple kinetic explanation of Raoult's law and the colligative properties of dilute aqueous solutions. The diffusive model explains that when a water molecule jumps from low to high osmolarity at equilibrium, the free energy change is zero because the work done pressurizing the water molecule is balanced by the entropy of mixing. It also explains that equal chemical potentials are required for particle exchange equilibrium in analogy with the familiar requirement of equal temperatures at thermal equilibrium.

  1. Improved Maximum Entropy Analysis with an Extended Search Space

    E-Print Network [OSTI]

    Alexander Rothkopf

    2013-01-07T23:59:59.000Z

    The standard implementation of the Maximum Entropy Method (MEM) follows Bryan and deploys a Singular Value Decomposition (SVD) to limit the dimensionality of the underlying solution space apriori. Here we present arguments based on the shape of the SVD basis functions and numerical evidence from a mock data analysis, which show that the correct Bayesian solution is not in general recovered with this approach. As a remedy we propose to extend the search basis systematically, which will eventually recover the full solution space and the correct solution. In order to adequately approach problems where an exponentially damped kernel is used, we provide an open-source implementation, using the C/C++ language that utilizes high precision arithmetic adjustable at run-time. The LBFGS algorithm is included in the code in order to attack problems without the need to resort to a particular search space restriction.

  2. Entropy and Energy: Toward a Definition of Physical Sustainability

    E-Print Network [OSTI]

    Hermanowicz, Slawomir W

    2005-01-01T23:59:59.000Z

    of entropy-energy definition of sustainability as well asand Energy: Toward a Definition of Physical Sustainabilityto assess the sustainability is based on the energy. This

  3. Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field

    E-Print Network [OSTI]

    Wung-Hong Huang

    2014-11-11T23:59:59.000Z

    The generalized gravitational entropy proposed by Lewkowycz and Maldacena in recent is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.

  4. The Effects of Quantum Entropy on the Bag Constant

    E-Print Network [OSTI]

    Miller, D E; Miller, David E.; Tawfik, Abdel-Nasser

    2003-01-01T23:59:59.000Z

    The effects of quantum entropy on the bag constant are studied at low temperatures and small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag constant without the quantum entropy almost does not change with the temperature and the quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant.

  5. approximate entropy based: Topics by E-print Network

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

    equation (1) nt + div n n Jngel, Ansgar 7 Regularization with Approximated L2 Maximum Entropy Method Physics Websites Summary: of a generalized moment of defined...

  6. Solving Maximum-Entropy Sampling Problems Using Factored Masks

    E-Print Network [OSTI]

    Samuel Burer

    2005-03-02T23:59:59.000Z

    Mar 2, 2005 ... Abstract: We present a practical approach to Anstreicher and Lee's masked spectral bound for maximum-entropy sampling, and we describe ...

  7. A masked spectral bound for maximum-entropy sampling

    E-Print Network [OSTI]

    Kurt Anstreicher

    2003-09-16T23:59:59.000Z

    Sep 16, 2003 ... Abstract: We introduce a new masked spectral bound for the maximum-entropy sampling problem. This bound is a continuous generalization of ...

  8. Maximum entropy generation in open systems: the Fourth Law?

    E-Print Network [OSTI]

    Umberto Lucia

    2010-11-17T23:59:59.000Z

    This paper develops an analytical and rigorous formulation of the maximum entropy generation principle. The result is suggested as the Fourth Law of Thermodynamics.

  9. activity response entropy: Topics by E-print Network

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

    using social media Lerman, Kristina 15 The Atmospheric Response to Surface Heating under Maximum Entropy Production A. GJERMUNDSEN, J. H. LACASCE, AND L. S. GRAFF Geosciences...

  10. IBM Research Report Solving Maximum-Entropy Sampling ...

    E-Print Network [OSTI]

    2005-02-28T23:59:59.000Z

    Feb 28, 2005 ... Solving Maximum-Entropy Sampling Problems Using. Factored Masks. Samuel Burer. Department of Management Sciences. University of Iowa.

  11. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings

    SciTech Connect (OSTI)

    Van Weele, S. (Foster Wheeler Development Corp., Livingston, NJ (United States))

    1991-08-01T23:59:59.000Z

    Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

  12. Vehicle Technologies Office Merit Review 2014: High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines 2012 FOA 648 Topic 3a

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  13. THE INFLUENCE OF RETAINED AUSTENITE ON THE THICK SECTION MECHANICAL PROPERTIES OF A COMMERCIAL LOW ALLOY ULTRA-HIGH STRENGTH STEEL

    E-Print Network [OSTI]

    Horn, R.M.

    2010-01-01T23:59:59.000Z

    of Fracture of High Strength Steels, Final Tech. Report,Arsenal Lab. , K. J. Irvine, Steel Strengthening Mechanisms,Diagrams, United States Steel, Pittsburgh, PA, 1963. E. G.

  14. Quinary metallic glass alloys

    DOE Patents [OSTI]

    Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    1998-01-01T23:59:59.000Z

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  15. Quinary metallic glass alloys

    DOE Patents [OSTI]

    Lin, X.; Johnson, W.L.

    1998-04-07T23:59:59.000Z

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3}K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf){sub a}(Al,Zn){sub b}(Ti,Nb){sub c}(Cu{sub x}Fe{sub y}(Ni,Co){sub z}){sub d} wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d{hor_ellipsis}y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  16. Segregation at the surfaces of Cu{sub x}Pd{sub 1-x} alloys in the presence of adsorbed S

    SciTech Connect (OSTI)

    Miller, James B.; Priyadarshini, Deepika; Gellman, Andrew J.

    2011-10-01T23:59:59.000Z

    The influence of adsorbed S on surface segregation in Cu{sub x}Pd{sub 1 ? x} alloys (S/Cu{sub x}Pd{sub 1 ? x)} was characterized over a wide range of bulk alloy compositions (x = 0.05 to 0.95) using high-throughput Composition Spread Alloy Film (CSAF) sample libraries. Top-surface and near-surface compositions of the CSAFs were measured as functions of bulk Cu composition, x, and temperature using spatially resolved low energy ion scattering spectroscopy (LEISS) and X-ray photoemission spectroscopy (XPS). Preferential segregation of Cu to the top-surface of the S/Cu{sub x}Pd{sub 1 ? x} CSAF was observed at all bulk compositions, x, but the extent of Cu segregation to the S/Cu{sub x}Pd{sub 1 ? x} surface was lower than the Cu segregation to the surface of a clean Cu{sub x}Pd{sub 1 ? x} CSAF, clear evidence of an S-induced “segregation reversal.” The Langmuir–McLean formulation of the Gibbs isotherm was used to estimate the enthalpy and entropy of Cu segregation to the top-surface, ?H{sub seg}(x) and ?S{sub seg}(x), at saturation sulfur coverages. While Cu segregation to the top-surface of the clean Cu{sub x}Pd{sub 1 ? x} is exothermic (?H{sub seg} < 0) for all bulk Cu compositions, it is endothermic (?H{sub seg} > 0) for S/Cu{sub x}Pd{sub 1 ? x}. Segregation to the S/Cu{sub x}Pd{sub 1 ? x} surface is driven by entropy. Changes in segregation patterns that occur upon adsorption of S onto Cu{sub x}Pd{sub 1 ? x} appear to be related to formation of energetically favored Pd{single bond}S bonds at the surface, which counterbalance the enthalpic driving forces for Cu segregation to the clean surface.

  17. Process for making a martensitic steel alloy fuel cladding product

    DOE Patents [OSTI]

    Johnson, Gerald D. (Kennewick, WA); Lobsinger, Ralph J. (Kennewick, WA); Hamilton, Margaret L. (Richland, WA); Gelles, David S. (West Richland, WA)

    1990-01-01T23:59:59.000Z

    This is a very narrowly defined martensitic steel alloy fuel cladding material for liquid metal cooled reactors, and a process for making such a martensitic steel alloy material. The alloy contains about 10.6 wt. % chromium, about 1.5 wt. % molybdenum, about 0.85 wt. % manganese, about 0.2 wt. % niobium, about 0.37 wt. % silicon, about 0.2 wt. % carbon, about 0.2 wt. % vanadium, 0.05 maximum wt. % nickel, about 0.015 wt. % nitrogen, about 0.015 wt. % sulfur, about 0.05 wt. % copper, about 0.007 wt. % boron, about 0.007 wt. % phosphorous, and with the remainder being essentially iron. The process utilizes preparing such an alloy and homogenizing said alloy at about 1000.degree. C. for 16 hours; annealing said homogenized alloy at 1150.degree. C. for 15 minutes; and tempering said annealed alloy at 700.degree. C. for 2 hours. The material exhibits good high temperature strength (especially long stress rupture life) at elevated temperature (500.degree.-760.degree. C.).

  18. Surface Engineering to Improve the Durability and Lubricity of Ti-6Al-4V Alloy

    SciTech Connect (OSTI)

    Bansal, Dinesh G [ORNL; Eryilmaz, Osman L [Argonne National Laboratory (ANL); Blau, Peter Julian [ORNL

    2011-01-01T23:59:59.000Z

    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.

  19. Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensembles out-of-equilibrium

    E-Print Network [OSTI]

    Crooks, Gavin E.

    2006-01-01T23:59:59.000Z

    1957). J. Skilling, in Maximum Entropy and Bayesian Methods,45–52. J. Skilling, in Maximum Entropy and Bayesian Methods,e C. C. Rodriguez, in Maximum Entropy and Bayesian Methods,

  20. Deriving the continuity of maximum-entropy basis functions via variational analysis

    E-Print Network [OSTI]

    Sukumar, N.; Wets, R. J. -B.

    2007-01-01T23:59:59.000Z

    and V. J. DellaPietra, A maximum entropy approach to naturalJ. and R. K. Bryan, Maximum entropy image reconstruction:Heidelberg, Continuity of maximum-entropy basis functions p

  1. Characterization of transuranium actinide alloy phase diagrams

    SciTech Connect (OSTI)

    Gibson, J.K.; Haire, R.G.; Gensini, M.M. [Oak Ridge National Lab., TN (United States); Ogawa, T. [Japan Atomic Energy Research Inst., Tokai (Japan)

    1994-05-02T23:59:59.000Z

    Alloys of Np have been studied less than those,of the neighboring elements, U and Pu; the higher actinides have received even less attention. Recent interest in {sup 237}Np, {sup 241}Am and other actinide isotopes as significant, long-lived and highly radiotoxic nuclear waste components, and particularly the roles of metallic materials new handling/separations and remediation technologies, demands that this paucity of information concerning alloy behaviors be addressed. An additional interest in these arises from the possibility of revealing fundamental properties and bonding interactions, which would further characterize the unique electronic structures (e.g., 5f electrons) of the actinide elements. The small empirical knowledge basis presently available for understanding and modeling the alloying behavior of Np is summarized here, with emphasis on our recent results for the Np-Am, Np-Zr and Np-Fe phase diag rams. In view of the limited experimental data base for neptunium and the transplutonium metals, the value of semi-empirical intermetallic bonding models for predicting actinide alloy thermodynamics is evaluated.

  2. Entropy: From Black Holes to Ordinary Systems

    E-Print Network [OSTI]

    J. P. Badiali

    2005-05-11T23:59:59.000Z

    Several results of black holes thermodynamics can be considered as firmly founded and formulated in a very general manner. From this starting point we analyse in which way these results may give us the opportunity to gain a better understanding in the thermodynamics of ordinary systems for which a pre-relativistic description is sufficient. First, we investigated the possibility to introduce an alternative definition of the entropy basically related to a local definition of the order in a spacetime model rather than a counting of microstates. We show that such an alternative approach exists and leads to the traditional results provided an equilibrium condition is assumed. This condition introduces a relation between a time interval and the reverse of the temperature. We show that such a relation extensively used in the black hole theory, mainly as a mathematical trick, has a very general and physical meaning here; in particular its derivation is not related to the existence of a canonical density matrix. Our dynamical approach of thermodynamic equilibrium allows us to establish a relation between action and entropy and we show that an identical relation exists in the case of black holes. The derivation of such a relation seems impossible in the Gibbs ensemble approach of statistical thermodynamics. From these results we suggest that the definition of entropy in terms of order in spacetime should be more general that the Boltzmann one based on a counting of microstates. Finally we point out that these results are obtained by reversing the traditional route going from the Schr\\"{o}dinger equation to statistical thermodynamics.

  3. Deriving the Qubit from Entropy Principles

    E-Print Network [OSTI]

    Adam Brandenburger; Pierfrancesco La Mura

    2015-01-22T23:59:59.000Z

    The Heisenberg uncertainty principle is one of the most famous features of quantum mechanics. However, the non-determinism implied by the Heisenberg uncertainty principle --- together with other prominent aspects of quantum mechanics such as superposition, entanglement, and nonlocality --- poses deep puzzles about the underlying physical reality, even while these same features are at the heart of exciting developments such as quantum cryptography, algorithms, and computing. These puzzles might be resolved if the mathematical structure of quantum mechanics were built up from physically interpretable axioms, but it is not. We propose three physically-based axioms which together characterize the simplest quantum system, namely the qubit. Our starting point is the class of all no-signaling theories. Each such theory can be regarded as a family of empirical models, and we proceed to associate entropies, i.e., measures of information, with these models. To do this, we move to phase space and impose the condition that entropies are real-valued. This requirement, which we call the Information Reality Principle, arises because in order to represent all no-signaling theories (including quantum mechanics itself) in phase space, it is necessary to allow negative probabilities (Wigner [1932]). Our second and third principles take two important features of quantum mechanics and turn them into deliberately chosen physical axioms. One axiom is an Uncertainty Principle, stated in terms of entropy. The other axiom is an Unbiasedness Principle, which requires that whenever there is complete certainty about the outcome of a measurement in one of three mutually orthogonal directions, there must be maximal uncertainty about the outcomes in each of the two other directions.

  4. Non-additive entropy: Reason and conclusions

    E-Print Network [OSTI]

    Miriam Lemanska

    2012-11-10T23:59:59.000Z

    In this work the non-additive entropy is examined. It appears in isolated particle systems composed of few components. Therefore, the mixing of isolated particle systems S=S1+S2 has been studied. Two cases are considered T1=T2 and T1\\leqT2, where T1,T2 are the initial temperatures of the system S1 and S2 respectively. The concept of similar systems containing interacting particles is introduced. These systems are defined by a common temperature and an identical time evolution process, i.e. the approach to the same thermodynamic equilibrium. The main results are: 1) The properties of the similar particle systems yield the non-additive entropy and free energy. The Gibbs Paradox is not a paradox. 2) The relation between the initial temperatures T1 and T2 governs the mixing process. 3) In the two cases T1=T2, T1\\leqT2 mixing of the systems S1, S2 results in a uniform union system S=S1+S2. The systems S, S1, S2 are similar one to the other. 4) The mixing process is independent of the extensive quantities (volume, particle number, energy) and of the particle type. Only the mean energy plays an important role in the mixing of the systems S1, S2. 5) Mixing in the case T1\\leqT2 is in essence a thermalization process, but mixing in the case T1=T2 is not a thermodynamic process. 6)Mixing is an irreversible process. Keywords: Entropy; Similar systems of interacting particles; Mixing of systems; Thermal equilibrium

  5. Thermodynamic Theory of Epitaxial Alloys: First-Principles Mixed-Basis Cluster Expansion of (In,Ga)N Alloy Film

    SciTech Connect (OSTI)

    Liu, J. Z.; Zunger, A.

    2009-01-01T23:59:59.000Z

    Epitaxial growth of semiconductor alloys onto a fixed substrate has become the method of choice to make high quality crystals. In the coherent epitaxial growth, the lattice mismatch between the alloy film and the substrate induces a particular form of strain, adding a strain energy term into the free energy of the alloy system. Such epitaxial strain energy can alter the thermodynamics of the alloy, leading to a different phase diagram and different atomic microstructures. In this paper, we present a general-purpose mixed-basis cluster expansion method to describe the thermodynamics of an epitaxial alloy, where the formation energy of a structure is expressed in terms of pair and many-body interactions. With a finite number of first-principles calculation inputs, our method can predict the energies of various atomic structures with an accuracy comparable to that of first-principles calculations themselves. Epitaxial (In, Ga)N zinc-blende alloy grown on GaN(001) substrate is taken as an example to demonstrate the details of the method. Two (210) superlattice structures, (InN){sub 2}/(GaN){sub 2} (at x = 0.50) and (InN){sub 4}/(GaN){sub 1} (at x = 0.80), are identified as the ground state structures, in contrast to the phase-separation behavior of the bulk alloy.

  6. Black Hole Radiation and Volume Statistical Entropy

    E-Print Network [OSTI]

    Mario Rabinowitz

    2005-06-29T23:59:59.000Z

    The simplest possible equation for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius which is similar to the Compton wavelength relation.

  7. Vehicle Technologies Office Merit Review 2015: High-Throughput Study of Diffusion and Phase Transformation Kinetics of Magnesium-Based Systems For Automotive Cast Magnesium Alloys

    Broader source: Energy.gov [DOE]

    Presentation given by Ohio State University at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high-throughput study...

  8. Niobium Silicon alloys for Kinetic Inductance Detectors

    E-Print Network [OSTI]

    Calvo, M; Monfardini, A; Benoit, A; Boudou, N; Bourrion, O; Catalano, A; Dumoulin, L; Goupy, J; Sueur, H Le; Marnieros, S

    2013-01-01T23:59:59.000Z

    We are studying the properties of Niobium Silicon amorphous alloys as a candidate material for the fabrication of highly sensitive Kinetic Inductance Detectors (KID), optimized for very low optical loads. As in the case of other composite materials, the NbSi properties can be changed by varying the relative amounts of its components. Using a NbSi film with T_c around 1 K we have been able to obtain the first NbSi resonators, observe an optical response and acquire a spectrum in the band 50 to 300 GHz. The data taken show that this material has very high kinetic inductance and normal state surface resistivity. These properties are ideal for the development of KID. More measurements are planned to further characterize the NbSi alloy and fully investigate its potential.

  9. Optimization of High-Volume Warm Forming for Lightweight Sheet...

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

    High-Volume Warm Forming for Lightweight Sheet Alloys Optimization of High-Volume Warm Forming for Lightweight Sheet Alloys 2012 DOE Hydrogen and Fuel Cells Program and Vehicle...

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

    SciTech Connect (OSTI)

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

    2013-02-20T23:59:59.000Z

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

  11. Fuel cell entropy production with ohmic heating and diffusive polarization

    E-Print Network [OSTI]

    Naterer, Greg F.

    Fuel cell entropy production with ohmic heating and diffusive polarization G.F. Naterer a,*, C production of ohmic heating and concentration polarization is investigated for two types of fuel cells (PEMFC oxide fuel cell (SOFC), this article formulates entropy production within electrodes of a proton

  12. A Counterexample to Additivity of Minimum Output Entropy

    E-Print Network [OSTI]

    M. B. Hastings

    2009-12-30T23:59:59.000Z

    We present a random construction of a pair of channels which gives, with non-zero probability for sufficiently large dimensions, a counterexample to the minimum output entropy conjecture. As shown by Shor, this implies a violation of the additivity conjecture for the classical capacity of quantum channels. The violation of the minimum output entropy conjecture is relatively small.

  13. Renyi entropies of a black hole from Hawking radiation

    E-Print Network [OSTI]

    A. Bialas; W. Czyz

    2008-01-30T23:59:59.000Z

    Renyi entropies of a black hole are evaluated by counting the states of the Hawking radiation which fills a thin shell surrounding the horizon. The width of the shell is determined from its energy content and the corresponding mass defect. The Bekenstein-Hawking formula for the entropy of the black hole is correctly reproduced.

  14. Filler metal alloy for welding cast nickel aluminide alloys

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    1998-01-01T23:59:59.000Z

    A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

  15. Filler metal alloy for welding cast nickel aluminide alloys

    DOE Patents [OSTI]

    Santella, M.L.; Sikka, V.K.

    1998-03-10T23:59:59.000Z

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  16. Salt Fog Testing Iron-Based Amorphous Alloys

    SciTech Connect (OSTI)

    Rebak, Raul B. [Chemistry and Materials Science, Lawrence Livermore National Laboratory, 7000 East Ave, L- 631, Livermore, CA, 94550 (United States); Aprigliano, Louis F. [Consultant, Berlin, MD, 21811 (United States); Day, S. Daniel; Farmer, Joseph C. [LLNL, Livermore, CA, 94550 (United States)

    2007-07-01T23:59:59.000Z

    Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

  17. Diamond tool wear of electrodeposited nickel-phosphorus alloy

    SciTech Connect (OSTI)

    Dini, J.W.; Donaldson, R.R.; Syn, C.K. (Lawrence Livermore National Lab., CA (USA)); Sugg, D.J. (Techmetals, Inc., Dayton, OH (USA))

    1990-02-01T23:59:59.000Z

    Nickel-Phosphorus alloys are attractive materials for diamond turning applications such as fabrication of large optics and other high precision parts. Although the mechanism is not understood, diamond tool wear is minimized when the phosphorus content of the deposit is greater than 11% (wgt). In recent years, increased attention has been directed at electrodeposition as an alternate to electroless deposition for producing Ni-P alloys. One principal advantage of the electrodeposition process is that alloys with 14--15% P can be obtained; another is that an order of magnitude greater deposition thickness can be provided if necessary. This paper compares diamond turning results for electrodeposited and electroless Ni-P alloys and shows that the electrodeposited coatings provide promising results. 28 refs., 7 figs., 1 tab.

  18. Ductile tungsten-nickel alloy and method for making same

    DOE Patents [OSTI]

    Snyder, Jr., William B. (Knoxville, TN)

    1976-01-01T23:59:59.000Z

    The present invention is directed to a ductile, high-density tungsten-nickel alloy which possesses a tensile strength in the range of 100,000 to 140,000 psi and a tensile elongation of 3.1 to 16.5 percent in 1 inch at 25.degree.C. This alloy is prepared by the steps of liquid phase sintering a mixture of tungsten-0.5 to 10.0 weight percent nickel, heat treating the alloy at a temperature above the ordering temperature of approximately 970.degree.C. to stabilize the matrix phase, and thereafter rapidly quenching the alloy in a suitable liquid to maintain the matrix phase in a metastable, face-centered cubic, solid- solution of tungsten in nickel.

  19. Strong converse theorems using Rényi entropies

    E-Print Network [OSTI]

    Felix Leditzky; Nilanjana Datta

    2015-06-08T23:59:59.000Z

    We use a R\\'enyi entropy approach to prove strong converse theorems for certain information-theoretic tasks which involve local operations and quantum (or classical) communication between two parties. These include state redistribution, coherent state merging, quantum state splitting, randomness extraction against quantum side information, and data compression with quantum side information. The method we employ in proving these results extends ideas developed by Sharma [arXiv:1404.5940] to prove the strong converse theorem for state merging. For state redistribution, we prove the strong converse property for the boundary of the entire achievable rate region in the $(e,q)$-plane, where $e$ and $q$ denote the entanglement cost and quantum communication cost, respectively. This extends a recent strong converse theorem for the quantum communication cost of state redistribution, proved by Berta et al. [arXiv:1409.4338]. For the other tasks as well, we provide new proofs for strong converse theorems which were previously established using smooth entropies.

  20. RELAP-7 Numerical Stabilization: Entropy Viscosity Method

    SciTech Connect (OSTI)

    R. A. Berry; M. O. Delchini; J. Ragusa

    2014-06-01T23:59:59.000Z

    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.

  1. Hydrodynamic equations for electrons in graphene obtained from the maximum entropy principle

    SciTech Connect (OSTI)

    Barletti, Luigi, E-mail: luigi.barletti@unifi.it [Dipartimento di Matematica e Informatica “Ulisse Dini”, Università degli Studi di Firenze, Viale Morgagni 67/A, 50134 Firenze (Italy)

    2014-08-15T23:59:59.000Z

    The maximum entropy principle is applied to the formal derivation of isothermal, Euler-like equations for semiclassical fermions (electrons and holes) in graphene. After proving general mathematical properties of the equations so obtained, their asymptotic form corresponding to significant physical regimes is investigated. In particular, the diffusive regime, the Maxwell-Boltzmann regime (high temperature), the collimation regime and the degenerate gas limit (vanishing temperature) are considered.

  2. Theoretical Studies of Hydrogen Storage Alloys.

    SciTech Connect (OSTI)

    Jonsson, Hannes

    2012-03-22T23:59:59.000Z

    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  3. A uranium-titanium-niobium alloy

    SciTech Connect (OSTI)

    Ludtka, G.M.; Ludtka, G.M.

    1990-02-23T23:59:59.000Z

    A uranium alloy having small additions of Ti and Nb shows improved strength and ductility in cross section of greater than one inch over prior uranium alloy having only Ti as an alloying element.

  4. Two phase titanium aluminide alloy

    DOE Patents [OSTI]

    Deevi, Seetharama C. (Midlothian, VA); Liu, C. T. (Oak Ridge, TN)

    2001-01-01T23:59:59.000Z

    A two-phase titanic aluminide alloy having a lamellar microstructure with little intercolony structures. The alloy can include fine particles such as boride particles at colony boundaries and/or grain boundary equiaxed structures. The alloy can include alloying additions such as .ltoreq.10 at % W, Nb and/or Mo. The alloy can be free of Cr, V, Mn, Cu and/or Ni and can include, in atomic %, 45 to 55% Ti, 40 to 50% Al, 1 to 5% Nb, 0.3 to 2% W, up to 1% Mo and 0.1 to 0.3% B. In weight %, the alloy can include 57 to 60% Ti, 30 to 32% Al, 4 to 9% Nb, up to 2% Mo, 2 to 8% W and 0.02 to 0.08% B.

  5. Single Interval R\\'enyi Entropy At Low Temperature

    E-Print Network [OSTI]

    Chen, Bin

    2015-01-01T23:59:59.000Z

    In this paper, we calculate the R\\'enyi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in $e^{-\\pi/TL}$ explicitly. On the other hand, we compute the same R\\'enyi entropy holographically. After considering the dependence of the R\\'enyi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic R\\'enyi entropy. We furthermore extend the analysis in Xi Dong's paper to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of R\\'enyi entropy in AdS$_3$/CFT$_2$ correspondence, even with thermal effect.

  6. Entropy and long-range correlations in DNA sequences

    E-Print Network [OSTI]

    S. S. Melnik; O. V. Usatenko

    2014-11-11T23:59:59.000Z

    We analyze the structure of DNA molecules of different organisms by using the additive Markov chain approach. Transforming nucleotide sequences into binary strings, we perform statistical analysis of the corresponding "texts". We develop the theory of N-step additive binary stationary ergodic Markov chains and analyze their differential entropy. Supposing that the correlations are weak we express the conditional probability function of the chain by means of the pair correlation function and represent the entropy as a functional of the pair correlator. Since the model uses two point correlators instead of probability of block occurring, it makes possible to calculate the entropy of subsequences at much longer distances than with the use of the standard methods. We utilize the obtained analytical result for numerical evaluation of the entropy of coarse-grained DNA texts. We believe that the entropy study can be used for biological classification of living species.

  7. Phase transformations in some hafnium-tantalum-titanium-zirconium alloys

    SciTech Connect (OSTI)

    Ohriner, E.K. [Oak Ridge National Lab., TN (United States); Kapoor, D. [Army ARDEC, Picatinny Arsenal, NJ (United States)

    1997-11-01T23:59:59.000Z

    Phase transformations in hafnium alloys are of interest as a means of achieving a material which exhibits flow softening and high localized strains during deformation at high strain rates. Hafnium transforms from a body-centered-cubic beta phase to a hexagonal alpha phase upon cooling below 1749{degrees}C. Hafnium-based alloys containing up to 17.5% Ti, up to 17.5% Ta, and up to 7.3% Zr by weight were button-arc melted and, in some cases, hot extruded to obtain a refined grain size. A number of alloys were shown to have beta solvus temperatures in the range of 1100 to 1300{degrees}C and showed evidence of a shear transformation upon water quenching. The Vickers microhardness of the quenched materials are typically above 350 HV as compared to 300 HV or less for materials with an alpha plus beta structure. Quenching dilatometry indicates a martensite start temperature of about 750{degrees}C for the Hf-7.5 Ta-10 Ti-1 Zr alloy and 800{degrees}C or more for the Hf-7.5 Ta-7.5 Ti-1 Zr alloy. Tensile tests at 1 s{sup {minus}1} strain rate show a constant ultimate tensile strength for temperatures up to 600{degrees}C for the above two alloys and a rapid decrease in strength with a further increase in temperature.

  8. Immersion studies on candidate container alloys for the Tuff Repository

    SciTech Connect (OSTI)

    Beavers, J.A.; Durr, C.L. [Cortest Columbus Technologies, OH (USA)

    1991-05-01T23:59:59.000Z

    Cortest Columbus Technologies (CC Technologies) is investigating the long-term performance of container materials used for high-level radioactive waste packages. This information is being developed for the Nuclear Regulatory Commission to aid in their assessment of the Department of Energy`s application to construct a geologic repository for disposal of high-level radioactive waste. This report summarizes the results of exposure studies performed on two copper-base and two Fe-Cr-Ni alloys in simulated Tuff Repository conditions. Testing was performed at 90{degrees}C in three environments; simulated J-13 well water, and two environments that simulated the chemical effects resulting from boiling and irradiation of the groundwater. Creviced specimens and U-bends were exposed to liquid, to vapor above the condensed phase, and to alternate immersion. A rod specimen was used to monitor corrosion at the vapor-liquid interface. The specimens were evaluated by electrochemical, gravimetric, and metallographic techniques following approximately 2000 hours of exposure. Results of the exposure tests indicated that all four alloys exhibited acceptable general corrosion rates in simulated J-13 well water. These rates decreased with time. Incipient pitting was observed under deposits on Alloy 825 and pitting was observed on both Alloy CDA 102 and Alloy CDA 715 in the simulated J-13 well water. No SCC was observed in U-bend specimens of any of the alloys in simulated J-13 well water. 33 refs., 48 figs., 23 tabs.

  9. Microstructure and corrosion behavior of die-cast AM60B magnesium alloys in a complex salt solution: A slow positron beam study

    SciTech Connect (OSTI)

    Liu, Y.F. [Wuhan University] [Wuhan University; Qin, Q.L. [Wuhan University] [Wuhan University; Yang, W. [Wuhan University] [Wuhan University; Wen, W. [University of Kentucky] [University of Kentucky; Zhai, T. [University of Kentucky] [University of Kentucky; Yu, B. [University of Alberta] [University of Alberta; Liu, D.Y. [University of Alberta] [University of Alberta; Luo, A. [GM Research and Development Center] [GM Research and Development Center; Song, GuangLing [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    The microstructure and corrosion behavior of high pressure die-cast (HPDC) and super vacuum die-cast (SVDC) AM60B magnesium alloys were investigated in a complex salt solution using slow positron beam technique and potentiodynamic polarization tests. The experiments revealed that a CaCO3 film was formed on the surface of the alloys and that the rate of CaCO3 formation for the SVDC alloy with immersion time was slower than that of the HPDC alloy. The larger volume fraction of b-phase in the skin layer of the SVDC alloy than that of the HPDC alloy was responsible for the better corrosion resistance.

  10. CHARACTERIZATION OF ELEVATED TEMPERATURE PROPERTIES OF HEAT EXCHANGER AND STEAM GENERATOR ALLOYS

    SciTech Connect (OSTI)

    J.K. Wright; L.J. Carroll; C.J. Cabet; T. Lillo; J.K. Benz; J.A. Simpson; A. Chapman; R.N. Wright

    2012-10-01T23:59:59.000Z

    The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800 C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950 C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600 C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. High temperature tensile testing of Alloy 617 has been conducted over a range of temperatures. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. Creep, fatigue, and creep-fatigue properties of Alloy 617 have been measured as well, with the goal of determining the influence of the temperature, strain rate and atmosphere on the creep fatigue life of Alloy 617. Elevated temperature properties and implications for codification of the alloys will be described.

  11. Shape memory alloy actuator

    DOE Patents [OSTI]

    Varma, Venugopal K. (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

  12. Duct and cladding alloy

    DOE Patents [OSTI]

    Korenko, Michael K. (Rockville, MD)

    1983-01-01T23:59:59.000Z

    An austenitic alloy having good thermal stability and resistance to sodium corrosion at 700.degree. C. consists essentially of 35-45% nickel 7.5-14% chromium 0.8-3.2% molybdenum 0.3-1.0% silicon 0.2-1.0% manganese 0-0.1% zirconium 2.0-3.5% titanium 1.0-2.0% aluminum 0.02-0.1% carbon 0-0.01% boron and the balance iron.

  13. Brittle Fracture in a 50Mo-50Re alloy in static tensile testing

    SciTech Connect (OSTI)

    Xu, Jianhui [University of Kentucky, Lexington; Kenik, Edward A [ORNL; Zhai, Tongguang [University of Kentucky, Lexington

    2008-01-01T23:59:59.000Z

    Tensile tests were conducted on 50Mo-50Re alloys, in fully-recrystallized and recovery heat-treated conditions respectively, at a very low strain rate of 10-6 s-1 and room temperature in air. It was found that both these alloys exhibited predominantly cleavage fracture with significant intergranular secondary cracking, compared to the predominantly ductile fracture found in the alloys at a higher strain rate. Cracks were often initiated at grain boundary triple junctions at the low strain rate. Electron back scatter diffraction (EBSD) measurements revealed significantly high misorientation gradients at grain boundaries, especially in the vicinity of some grain boundary triple junctions in the deformed alloys. Transmission electron microscopic (TEM) results verified the existence of significant misorientation taking place at grain boundaries in these alloys. Stress-assisted dynamic embrittlement, possibly due to trace interstitials, was the possible cause for the occurrence of brittle fracture in the 50Mo-50Re alloys at the low strain rate.

  14. Void swelling resistance in Fe-Cr alloys at 200 dpa

    SciTech Connect (OSTI)

    Gelles, D.S. [Pacific Northwest Lab., Richland, WA (United States)

    1995-09-01T23:59:59.000Z

    Microstructural examinations have been performed on a serious of binary Fe-cr alloys irradiated to 200 dpa at 425 C in a fast breeder reactor. The alloy compositions ranged from 3% to 18% Cr in 3% Cr increments, and the irradiation temperature corresponded to the peak swelling condition for this alloy class. Density measurements showed swelling levels as high as 7.4%, with the highest swelling found in the Fe-9Cr and Fe-6Cr alloys. Microstructural examinations revealed that the highest swelling conditions contained well-developed voids, often as large as 100 nm, and a dislocation network comprised of both a/2<111> and a<100> Burgers vectors. Swelling was lower in the other alloys, and the swelling reduction could be correlated with increased precipitation. These results are considered in light of the current theories for low swelling in ferritic alloys, but no theory is available to completely explain the results.

  15. Aluminum-lithium alloys -- the next generation

    SciTech Connect (OSTI)

    Webster, D. (Advanced Material Development, Saratoga, CA (United States))

    1994-05-01T23:59:59.000Z

    The advantages of aluminum-lithium (Al-Li) alloys, such as low density and high modulus, have been well documented in the last 15 years, but their impact on the aerospace market has fallen short of initial expectations. However, vacuum refining processes have now been developed at Comalco Aluminium Ltd., Melbourne, Australia, that provide improved mechanical properties. In addition, the patented technology allows higher levels of lithium, which results in higher stiffness and lower densities. For example, alloys with 3.3% lithium and very low amounts of hydrogen and alkali metal impurities demonstrate good mechanical properties. It also exhibits good weldability, as shown in results of varestraint'' testing, which evaluates the tendency to crack during welding. The high purity of these VacLite alloys ensures that grain boundary fracture is minimized, and cleavage fracture is reduced almost to the limit of detectability. Furthermore, advanced vacuum techniques using electron beam melting at 10[sup [minus]5] torr may eventually reduce impurities to a level at which fracture occurs only in a ductile, transgranular manner.

  16. Radiation resistant austenitic stainless steel alloys

    DOE Patents [OSTI]

    Maziasz, Philip J. (Oak Ridge, TN); Braski, David N. (Oak Ridge, TN); Rowcliffe, Arthur F. (Oak Ridge, TN)

    1989-01-01T23:59:59.000Z

    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01% to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties.

  17. Radiation resistant austenitic stainless steel alloys

    DOE Patents [OSTI]

    Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

    1987-02-11T23:59:59.000Z

    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

  18. Towards Black Hole Entropy in Shape Dynamics

    E-Print Network [OSTI]

    Gabriel Herczeg; Vasudev Shyam

    2014-10-21T23:59:59.000Z

    Shape dynamics is classical theory of gravity which agrees with general relativity in many important cases, but possesses different gauge symmetries and constraints. Rather than spacetime diffeomorphism invariance, shape dynamics takes spatial diffeomorphism invariance and spatial Weyl invariance as the fundamental gauge symmetries associated with the gravitational field. Since the area of the event horizon of a black hole transforms under a generic spatial Weyl transformation, there has been some doubt that one can speak sensibly about the thermodynamics of black holes in shape dynamics. The purpose of this paper is to show that by treating the event horizon of a black hole as an interior boundary, one can recover familiar notions of black hole thermodynamics in shape dynamics and define a gauge invariant entropy that agrees with general relativity.

  19. Entropy & viscosity bound of strange stars

    E-Print Network [OSTI]

    Sibasish Laha; Taparati Gangopadhyay; Manjari Bagchi; Mira Dey; Jishnu Dey; Monika Sinha; Subharthi Ray

    2007-02-08T23:59:59.000Z

    At finite temperature (T) there is a link with general relativity and hydrodynamics that leads to a lower bound for the ratio of shear viscosity and entropy density (\\eta/s). We find that the bound is saturated in the simple model for quark matter that we use for strange stars at T = 80 MeV, at the surface of a strange star. At this T we have the possibility of cosmic separation of phases. We find that, although strongly correlated, the quark matter at the surface of strange stars constitute the most perfect interacting fluid permitted by nature. At the centre of the star, however, the density is higher and conditions are more like the results found for perturbative QCD.

  20. Entanglement entropy from the holographic stress tensor

    E-Print Network [OSTI]

    Arpan Bhattacharyya; Aninda Sinha

    2013-10-15T23:59:59.000Z

    We consider entanglement entropy in the context of gauge/gravity duality for conformal field theories in even dimensions. The holographic prescription due to Ryu and Takayanagi (RT) leads to an equation describing how the entangling surface extends into the bulk geometry. We show that setting to zero the time-time component of the Brown-York stress tensor evaluated on the co-dimension one entangling surface, leads to the same equation. By considering a spherical entangling surface as an example, we observe that Euclidean action methods in AdS/CFT will lead to the RT area functional arising as a counterterm needed to regularize the stress tensor. We present arguments leading to a justification for the minimal area prescription.

  1. Entanglement entropy in higher derivative holography

    E-Print Network [OSTI]

    Arpan Bhattacharyya; Apratim Kaviraj; Aninda Sinha

    2013-08-16T23:59:59.000Z

    We consider holographic entanglement entropy in higher derivative gravity theories. Recently Lewkowycz and Maldacena arXiv:1304.4926 have provided a method to derive the equations for the entangling surface from first principles. We use this method to compute the entangling surface in four derivative gravity. Certain interesting differences compared to the two derivative case are pointed out. For Gauss-Bonnet gravity, we show that in the regime where this method is applicable, the resulting equations coincide with proposals in the literature as well as with what follows from considerations of the stress tensor on the entangling surface. Finally we demonstrate that the area functional in Gauss-Bonnet holography arises as a counterterm needed to make the Euclidean action free of power law divergences.

  2. Renormalization group flow of entanglement entropy on spheres

    E-Print Network [OSTI]

    Ben-Ami, Omer; Smolkin, Michael

    2015-01-01T23:59:59.000Z

    We explore entanglement entropy of a cap-like region for a generic quantum field theory residing in the Bunch-Davies vacuum on de Sitter space. Entanglement entropy in our setup is identical with the thermal entropy in the static patch of de Sitter, and we derive a simple relation between the vacuum expectation value of the energy-momentum tensor trace and the RG flow of entanglement entropy. In particular, renormalization of the cosmological constant and logarithmic divergence of the entanglement entropy are interrelated in our setup. We confirm our findings by recovering known universal contributions for a free field theory deformed by a mass operator as well as obtain correct universal behaviour at the fixed points. Simple examples of entanglement entropy flows are elaborated in $d=2,3,4$. In three dimensions we find that while the renormalized entanglement entropy is stationary at the fixed points, it is not monotonic. We provide a computational evidence that the universal `area law' for a conformally cou...

  3. Method of making active magnetic refrigerant materials based on Gd-Si-Ge alloys

    DOE Patents [OSTI]

    Pecharsky, Alexandra O. (Ames, IA); Gschneidner, Jr., Karl A. (Ames, IA); Pecharsky, Vitalij K. (Ames, IA)

    2006-10-03T23:59:59.000Z

    An alloy made of heat treated material represented by Gd.sub.5(Si.sub.xGe.sub.1-x).sub.4 where 0.47.ltoreq.x.ltoreq.0.56 that exhibits a magnetic entropy change (-.DELTA.S.sub.m) of at least 16 J/kg K, a magnetostriction of at least 2000 parts per million, and a magnetoresistance of at least 5 percent at a temperature of about 300K and below, and method of heat treating the material between 800 to 1600 degrees C. for a time to this end.

  4. Shape Memory Alloys and Their Applications in Power Generation and Refrigeration

    SciTech Connect (OSTI)

    Cui, Jun

    2013-03-27T23:59:59.000Z

    The shape memory effect is closely related to the reversible martensitic phase transformation, which is diffusionless and involves shear deformation. The recoverable transformation between the two phases with different crystalline symmetry results in reversible changes in physical properties such as electrical conductivity, magnetization, and elasticity. Accompanying the transformation is a change of entropy. Fascinating applications are developed based on these changes. In this paper, the history, fundamentals and technical challenges of both thermoelastic and ferromagnetic shape memory alloys are briefly reviewed; applications related to energy conversion such as power generation and refrigeration as well as recent developments will be discussed.

  5. Shape Memory Alloys and their Applications in Power Generation and Refrigeration

    SciTech Connect (OSTI)

    Cui, Jun

    2013-07-01T23:59:59.000Z

    The shape memory effect is closely related to the reversible martensitic phase transformation, which is diffusionless and involves shear deformation. The recoverable transformation between the two phases with different crystalline symmetry results in reversible changes in physical properties such as electrical conductivity, magnetization, and elasticity. Accompanying the transformation is a change of entropy. Fascinating applications are developed based on these changes. In this paper, the history, fundamentals and technical challenges of both thermoelastic and ferromagnetic shape memory alloys are briefly reviewed; applications related to energy conversion such as power generation and refrigeration as well as recent developments will be discussed.

  6. Entropy of quantum channel in the theory of quantum information

    E-Print Network [OSTI]

    Wojciech Roga

    2011-10-03T23:59:59.000Z

    Quantum channels, also called quantum operations, are linear, trace preserving and completely positive transformations in the space of quantum states. Such operations describe discrete time evolution of an open quantum system interacting with an environment. The thesis contains an analysis of properties of quantum channels and different entropies used to quantify the decoherence introduced into the system by a given operation. Part I of the thesis provides a general introduction to the subject. In Part II, the action of a quantum channel is treated as a process of preparation of a quantum ensemble. The Holevo information associated with this ensemble is shown to be bounded by the entropy exchanged during the preparation process between the initial state and the environment. A relation between the Holevo information and the entropy of an auxiliary matrix consisting of square root fidelities between the elements of the ensemble is proved in some special cases. Weaker bounds on the Holevo information are also established. The entropy of a channel, also called the map entropy, is defined as the entropy of the state corresponding to the channel by the Jamiolkowski isomorphism. In Part III of the thesis, the additivity of the entropy of a channel is proved. The minimal output entropy, which is difficult to compute, is estimated by an entropy of a channel which is much easier to obtain. A class of quantum channels is specified, for which additivity of channel capacity is conjectured. The last part of the thesis contains characterization of Davies channels, which correspond to an interaction of a state with a thermal reservoir in the week coupling limit, under the condition of quantum detailed balance and independence of rotational and dissipative evolutions. The Davies channels are characterized for one-qubit and one-qutrit systems.

  7. Crystallization in Al88RE8Ni4 Glass Forming Alloys T.K. Croat, A. K. Gangopadhyay, and K. F. Kelton

    E-Print Network [OSTI]

    of the phase separated regions. Keywords: analytical electron microscopy, metallic glasses, aluminum alloys to conventional aluminum alloys. Attempts have been made to attribute the high density of nanocrystalsCrystallization in Al88RE8Ni4 Glass Forming Alloys T.K. Croat, A. K. Gangopadhyay, and K. F. Kelton

  8. Surface Studies of HSLA [high strength low alloy] Steel after Electrochemical Corrosion in Supercritical CO{sub 2}-H{sub 2}O Environment

    SciTech Connect (OSTI)

    Ziomek-Moroz, M. Holcomb, G. Tylczak, J Beck, J Fedkin, M. Lvov, S.

    2011-10-11T23:59:59.000Z

    Corrosion resistance of pipeline materials for transporting coal combustion produced supercritical CO{sub 2} from power plants to sequestration sites has not been fully determined. Although pipeline materials are resistant to corrosion in pure supercritical CO{sub 2}, cleaning costs of combustion produced CO{sub 2} streams from impurities such as H{sub 2}O, O{sub 2}, SO{sub 2} are too high, making sequestration of pure CO{sub 2} streams unfeasible. Impacts of the H{sub 2}O, O{sub 2}, SO{sub 2} impurities on pipeline corrosion must be determined. Filling Up This Technological Gap requires studying effects of H{sub 2}O, O{sub 2}, SO{sub 2} concentrations on pipeline.

  9. Ris-R-1523(EN) Properties of Mg-Al alloys in relation to

    E-Print Network [OSTI]

    engines or fuel cells working at higher temperatures than the PEM. Besides the high gravimetric hydrogen fuel cell in future mobile applications. A variety of alloying elements have been explored in orderRisø-R-1523(EN) Properties of Mg-Al alloys in relation to hydrogen storage Anders Andreasen

  10. MEASUREMENTS OF SPECIFIC ELECTRICAL CONTACT RESISTANCE BETWEEN SIC AND LEAD-LITHIUM EUTECTIC ALLOY

    E-Print Network [OSTI]

    Abdou, Mohamed

    MEASUREMENTS OF SPECIFIC ELECTRICAL CONTACT RESISTANCE BETWEEN SIC AND LEAD-LITHIUM EUTECTIC ALLOY Neil B. Morley, Albert Medina, and Mohamed A. Abdou Mechanical &Aerospace Engineering, UCLA, Los resistance of disks of high purity CVD SiC were measured with liquid lead-lithium eutectic (LLE) alloy melts

  11. Mechanical Flow Response and Anisotropy of Ultra-Fine Grained Magnesium and Zinc Alloys

    E-Print Network [OSTI]

    Al Maharbi, Majid H.

    2011-02-22T23:59:59.000Z

    asymmetry, and the mechanisms responsible for these phenomena in two hcp materials: AZ31B Mg alloy consisting of one phase and Zn-8wt.% Al that has an hcp matrix with a secondary facecentered cubic (fcc) phase. Mg and its alloys have high specific strength...

  12. Chapter 11 HELIUM-COOLED REFRACTORY ALLOYS FIRST WALL AND BLANKET EVALUATION

    E-Print Network [OSTI]

    California at Los Angeles, University of

    1 Chapter 11 HELIUM-COOLED REFRACTORY ALLOYS FIRST WALL AND BLANKET EVALUATION 11.1 Introduction performed thermal hydraulics, nuclear, activation and safety designs and analysis. High-pressure helium of the refractory alloy helium-cooled breeder FW/blanket concept developed under the APEX program is presented

  13. Shape memory alloy thaw sensors

    SciTech Connect (OSTI)

    Shahinpoor, Mohsen (Albuquerque, NM); Martinez, David R. (Albuquerque, NM)

    1998-01-01T23:59:59.000Z

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

  14. ENTROPY PRODUCTION IN THERMOSTATS II NURLAN S. DAIRBEKOV AND GABRIEL P. PATERNAIN

    E-Print Network [OSTI]

    Paternain, Gabriel P.

    that an arbitrary Anosov Gaussian thermostat close to equi- librium has positive entropy poduction unless

  15. Divergence of Lubkin's series for a quantum subsystem's mean entropy

    E-Print Network [OSTI]

    Jacob P Dyer

    2014-09-17T23:59:59.000Z

    In 1978, Lubkin proposed a method of approximating the mean von Neumann entropy for a subsystem of a finite-dimensional quantum system in an overall pure state by expanding the entropy as a series in terms of the mean trace of powers of the system's reduced density operator, but the convergence of this series was never established. We find an exact closed form expression for the mean traces, which enables us to prove that the series converges if and only if the system's dimension $m\\le2$, in spite of the fact that Lubkin's proposed approximation for the entropy is now known to be correct.

  16. Active Brownian particles: Entropy production and fluctuation-response

    E-Print Network [OSTI]

    Chaudhuri, Debasish

    2014-01-01T23:59:59.000Z

    Within the Rayleigh-Helmholtz model of active Brownian particles activity is due to a non-linear velocity dependent force. In the presence of an external trapping potential or a constant force, the steady state of the system breaks detailed balance producing a net entropy. Using molecular dynamics simulations, we obtain the probability distributions of entropy production in these steady states. The distribution functions obey detailed fluctuation theorem for entropy production. Using simulation results, we further show that the steady state response function obeys a modified fluctuation-dissipation relation.

  17. Entanglement entropy from surface terms in general relativity

    E-Print Network [OSTI]

    Arpan Bhattacharyya; Aninda Sinha

    2013-09-10T23:59:59.000Z

    Entanglement entropy in local quantum field theories is typically ultraviolet divergent due to short distance effects in the neighbourhood of the entangling region. In the context of gauge/gravity duality, we show that surface terms in general relativity are able to capture this entanglement entropy. In particular, we demonstrate that for 1+1 dimensional CFTs at finite temperature whose gravity dual is the BTZ black hole, the Gibbons-Hawking-York term precisely reproduces the entanglement entropy which can be computed independently in the field theory.

  18. General proof of entropy principle in Einstein-Maxwell theory

    E-Print Network [OSTI]

    Fang, Xiongjun

    2015-01-01T23:59:59.000Z

    We consider a static self-gravitating charged perfect fluid system in the Einstein-Maxwell theory. Assume Maxwell's equation and the Einstein constraint equation are satisfied, and the temperature of the fluid obeys Tolman's law. Then we prove that the total entropy of the fluid achieves an extremum implies other components of Einstein's equation for any variations of metric and electrical potential with fixed boundary values. Conversely, if Einstein's equation and Maxwell's equations hold, the total entropy achieves an extremum. Our work suggests that the maximum entropy principle is consistent with Einstein's equation when electric field is taken into account.

  19. Entropy based Nearest Neighbor Search in High Dimensions Rina Panigrahy #

    E-Print Network [OSTI]

    Pratt, Vaughan

    functions (that tend to map nearby points to the same value) to construct several hash tables to ensure a data structure of size � O(n 1/(1-#) ) to answer queries in � O(d) time. By applying this analysis dimensional Euclidean space: given a database of n points in a d # Department of Computer Science, Stanford

  20. CORROSION RESISTANCE OF DENTAL ALLOYS

    E-Print Network [OSTI]

    Belma Muhamedagi?; Bosna I Hercegovina; Lejla Muhamedagi?; Bosna I Hercegovina

    Metals and metallic alloys are unavoidable materials in everyday dental use for the making of fillings, cast cores and post systems, individual crowns, implantants ’ suprastructures, dentures and orthodontic devices. They still belong to the vital materials in dentistry. Applied alloys in a mouth are exposed to the influence of chemical, biological, mechanical, thermal and electrical forces which can have a negative impact on a very therapeutic work or surrounding tissue. Electrochemical corrosion is the most important damaging factor of dental works. The corrosive resistance of metal is its important characteristic during implantation into a mouth. Therefore precious alloys are the most suitable for dental use. However, due to economic reasons, nonprecious alloys are frequently used, while corrosive resistant precious metals have been used less frequently. Based on studying different literature, the purpose of this work was to give and overview of the existing dental metals and alloys in contexts with their anticorrosive characteristics.

  1. Scanning Electron Microscopy Analysis of Fuel/Matrix Interaction Layers in Highly-Irradiated U–Mo Dispersion Fuel Plates with Al and Al–Si Alloy Matrices

    SciTech Connect (OSTI)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Brandon D. Miller; Jian Gan; Adam B. Robinson; Pavel Medvedev; James Madden; Dan Wachs; Mitch Meyer

    2014-04-01T23:59:59.000Z

    In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U–7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U–7Mo dispersion fuel elements with pure Al, Al–2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U–7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission-gas bubbles. Additionally, solid-fission-product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U–7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al–Si matrices.

  2. Wedlable nickel aluminide alloy

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    2002-11-19T23:59:59.000Z

    A Ni.sub.3 Al alloy with improved weldability is described. It contains about 6-12 wt % Al, about 6-12 wt % Cr, about 0-3 wt % Mo, about 1.5-6 wt % Zr, about 0-0.02 wt % B and at least one of about 0-0.15 wt % C, about 0-0.20 wt % Si, about 0-0.01 wt % S and about 0-0.30 wt % Fe with the balance being Ni.

  3. CHARACTERIZATION OF SHAPE MEMORY ALLOY BEHAVIOR AND

    E-Print Network [OSTI]

    Valasek, John

    CHARACTERIZATION OF SHAPE MEMORY ALLOY BEHAVIOR AND POSITION CONTROL USING REINFORCEMENT LEARNING for Intelligent Bio-Nano Materials and Structures for Aerospace Vehicles Problem: Shape Memory Alloy and Structures for Aerospace Vehicles 4 Shape Memory Alloys (SMAs) Metallic Alloys used as actuators Shape Memory

  4. Effect of heat-treatment on properties of electroless-deposited nickel-molybdenum-phosphorus alloy films

    SciTech Connect (OSTI)

    Koiwa, I.; Usuda, M.; Yamada, K.; Osaka, T.

    1988-03-01T23:59:59.000Z

    The film properties and the heat change properties of new electroless plated Ni-Mo-P alloy films, which were deposited from a newly developed simpler bath with direct addition of Na/sub 2/MoO/sub 4/, were investigated as a basis for developing new functional thin film. Both amorphous and crystallized Ni-Mo-P alloy films were prepared by simply controlling the Na/sub 2/-MoO/sub 4/ concentration in the baths. The maximum molybdenum content of 14.9 atom percent (22.3 weight percent) was attained at a Na/sub 2/MoO/sub 4/ concentration of 0.020 mol dm /sup -3/, and the films having high resistivity and high thermal stability were obtained. The formation of solid solution between Ni matrix and codeposited Mo was indicated on the basis of comparison with bulk Ni-Mo alloy. The amorphous Ni-Mo-P alloy film had much better thermal stability than did the amorphous Ni-P alloy film. In the case of crystallized Ni-Mo-P alloy film, the small grain size of electroless Ni-Mo-P alloy film was maintained even after heat-treatment up to 400/sup 0/C. The crystallization process of the amorphous and crystallized Ni-Mo-P alloy films by heat-treatment was quite different from that of an ordinary electroless Ni-P alloy film. Three structural changes resulting from heat-treatment were observed in electroless Ni-Mo-P alloy films, namely, The formation of Ni/sub 3/P, the crystallization of Ni-Mo alloy, and the transformation of Ni-Mo alloy. A schematic model of Ni-Mo-P alloy films composed of two phases or zones, namely, the Ni-Mo and Ni-Mo-P, was proposed to explain the heat change properties of Ni-Mo-P alloy films.

  5. Effect of entropy on anomalous transport in electron-temperature-gradient-modes

    SciTech Connect (OSTI)

    Yaqub Khan, M., E-mail: myaqubsultani@gmail.com [Department of Basic Sciences, Riphah International University, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Iqbal, J. [Department of Mathematics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ul Haq, A. [Faculty of Engineering and Applied Physics, Riphah International University, Islamabad 44000 (Pakistan)

    2014-05-15T23:59:59.000Z

    Due to the interconnection of entropy with temperature and density of plasma, it would be interesting to investigate plasma related phenomena with respect to entropy. By employing Braginskii transport equations, it is proved that entropy is proportional to a function of potential and distribution function of entropy is re-defined, ?S–drift in obtained. New dispersion relation is derived; it is found that the anomalous transport depends on the gradient of the entropy.

  6. Rotating embedded black holes: Entropy and Hawking's radiation

    E-Print Network [OSTI]

    Ng Ibohal

    2004-12-27T23:59:59.000Z

    In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.

  7. Entropy-energy balance in noisy quantum computers

    E-Print Network [OSTI]

    Maxim Raginsky

    2002-09-26T23:59:59.000Z

    We use entropy-energy arguments to assess the limitations on the running time and on the system size, as measured in qubits, of noisy macroscopic circuit-based quantum computers.

  8. A Remark on the Strict Positivity of the Entropy Production

    E-Print Network [OSTI]

    Walter H. Aschbacher; Herbert Spohn

    2005-07-05T23:59:59.000Z

    We establish an algebraic criterion which ensures the strict positivity of the entropy production in quantum models consisting of a small system coupled to thermal reservoirs at different temperatures.

  9. Of fishes and birthdays: Efficient estimation of polymer configurational entropies

    E-Print Network [OSTI]

    Nemenman, Ilya; Strauss, Charlie E

    2015-01-01T23:59:59.000Z

    We present an algorithm to estimate the configurational entropy $S$ of a polymer. The algorithm uses the statistics of coincidences among random samples of configurations and is related to the catch-tag-release method for estimation of population sizes, and to the classic "birthday paradox". Bias in the entropy estimation is decreased by grouping configurations in nearly equiprobable partitions based on their energies, and estimating entropies separately within each partition. Whereas most entropy estimation algorithms require $N\\sim 2^{S}$ samples to achieve small bias, our approach typically needs only $N\\sim \\sqrt{2^{S}}$. Thus the algorithm can be applied to estimate protein free energies with increased accuracy and decreased computational cost.

  10. Using entropy to drive search in occupancy grids

    E-Print Network [OSTI]

    Yao, Xin

    . Entropy 4. Infotaxis 5. Robotic mapping 6. Frat-house algorithms ( ) 7. Conclusions IRLab, 2 Feb 2010 analysis and path planning. Target for missions is to find as many vents as possible, given time/battery

  11. Holographic entanglement entropy in general holographic superconductor models

    E-Print Network [OSTI]

    Yan Peng; Qiyuan Pan

    2014-04-07T23:59:59.000Z

    We study the entanglement entropy of general holographic dual models both in AdS soliton and AdS black hole backgrounds with full backreaction. We find that the entanglement entropy is a good probe to explore the properties of the holographic superconductors and provides richer physics in the phase transition. We obtain the effects of the scalar mass, model parameter and backreaction on the entropy, and argue that the jump of the entanglement entropy may be a quite general feature for the first order phase transition. In strong contrast to the insulator/superconductor system, we note that the backreaction coupled with the scalar mass can not be used to trigger the first order phase transition if the model parameter is below its bottom bound in the metal/superconductor system.

  12. Rényi entropy, mutual information, and fluctuation properties of Fermi liquids

    E-Print Network [OSTI]

    Swingle, Brian Gordon

    We compute the leading contribution to the ground-state Rényi entropy S[subscript ?] for a region of linear size L in a Fermi liquid in d dimensions. The result contains a universal boundary law violating term simply related ...

  13. Novel Concepts for Damage-Resistant Alloys in Next Generation Nuclear Power Systems

    SciTech Connect (OSTI)

    Stephen M. Bruemmer; Peter L. Andersen; Gary Was

    2002-12-27T23:59:59.000Z

    The discovery of a damage-resistant alloy based on Hf solute additions to a low-carbon 316SS is the highlight of the Phase II research. This damage resistance is supported by characterization of radiation-induced microstructures and microchemistries along with measurements of environmental cracking. The addition of Hf to a low-carbon 316SS reduced the detrimental impact of radiation by changing the distribution of Hf. Pt additions reduced the impact of radiation on grain boundary segregation but did not alter its effect on microstructural damage development or cracking. Because cracking susceptibility is associated with several material characteristics, separate effect experiments exploring strength effects using non-irradiated stainless steels were conducted. These crack growth tests suggest that irradiation strength by itself can promote environmental cracking. The second concept for developing damage resistant alloys is the use of metastable precipitates to stabilize the microstructure during irradiation. Three alloys have been tailored for evaluation of precipitate stability influences on damage evolution. The first alloy is a Ni-base alloy (alloy 718) that has been characterized at low neutron irradiation doses but has not been characterized at high irradiation doses. The other two alloys are Fe-base alloys (PH 17-7 and PH 17-4) that have similar precipitate structures as alloy 718 but is more practical in nuclear structures because of the lower Ni content and hence lesser transmutation to He.

  14. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S. (Corvallis, OR); Alman, David E. (Salem, OR)

    2002-11-05T23:59:59.000Z

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800.degree. C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800.degree. C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700.degree. C. at a low cost

  15. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S.; Alman, David E.

    2002-11-05T23:59:59.000Z

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800 C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800 C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700 C. at a low cost

  16. Entropy production at freeze-out from dissipative fluids

    E-Print Network [OSTI]

    E. Molnar

    2007-09-17T23:59:59.000Z

    Entropy production due to shear viscosity during the continuous freeze-out of a longitudinally expanding dissipative fluid is addressed. Assuming the validity of the fluid dynamical description during the continuous removal of interacting matter we estimated a small entropy production as function of the freeze-out duration and the ratio of dissipative to non-dissipative quantities in case of a relativistic massless pion fluid.

  17. The maximum entropy tecniques and the statistical description of systems

    E-Print Network [OSTI]

    B. Z. Belashev; M. K. Suleymanov

    2001-10-19T23:59:59.000Z

    The maximum entropy technique (MENT) is used to determine the distribution functions of physical values. MENT naturally combines required maximum entropy, the properties of a system and connection conditions in the form of restrictions imposed on the system. It can, therefore, be employed to statistically describe closed and open systems. Examples in which MENT is used to describe equilibrium and non-equilibrium states, as well as steady states that are far from being in thermodynamic equilibrium, are discussed.

  18. PRECIPITATION HARDENING IN Fe-Ni BASE AUSTENITIC ALLOYS

    E-Print Network [OSTI]

    Chang, K.-M.

    2010-01-01T23:59:59.000Z

    age- hardening alloy contains titanium and aluminum as thecubic (fee) alloys, such as nickel, aluminum, copper, andon nickel-aluminum-ternary element alloys (see Fig. 1 ) .

  19. Dispersoid reinforced alloy powder and method of making - Energy...

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

    of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion andor oxidation resistance-imparting alloying element, a dispersoid-forming...

  20. Extreme solid state refrigeration using nanostructured Bi-Te alloys.

    SciTech Connect (OSTI)

    Lima Sharma, Ana L. (San Jose State University, San Jose, CA); Spataru, Dan Catalin; Medlin, Douglas L.; Sharma, Peter Anand; Morales, Alfredo Martin

    2009-09-01T23:59:59.000Z

    Materials are desperately needed for cryogenic solid state refrigeration. We have investigated nanostructured Bi-Te alloys for their potential use in Ettingshausen refrigeration to liquid nitrogen temperatures. These alloys form alternating layers of Bi{sub 2} and Bi{sub 2}Te{sub 3} blocks in equilibrium. The composition Bi{sub 4}Te{sub 3} was identified as having the greatest potential for having a high Ettingshausen figure of merit. Both single crystal and polycrystalline forms of this material were synthesized. After evaluating the Ettingshausen figure of merit for a large, high quality polycrystal, we simulated the limits of practical refrigeration in this material from 200 to 77 K using a simple device model. The band structure was also computed and compared to experiments. We discuss the crystal growth, transport physics, and practical refrigeration potential of Bi-Te alloys.

  1. Quantum maximum-entropy principle for closed quantum hydrodynamic transport within a Wigner function formalism

    SciTech Connect (OSTI)

    Trovato, M. [Dipartimento di Matematica, Universita di Catania, Viale A. Doria, I-95125 Catania (Italy); Reggiani, L. [Dipartimento di Ingegneria dell' Innovazione and CNISM, Universita del Salento, Via Arnesano s/n, I-73100 Lecce (Italy)

    2011-12-15T23:59:59.000Z

    By introducing a quantum entropy functional of the reduced density matrix, the principle of quantum maximum entropy is asserted as fundamental principle of quantum statistical mechanics. Accordingly, we develop a comprehensive theoretical formalism to construct rigorously a closed quantum hydrodynamic transport within a Wigner function approach. The theoretical formalism is formulated in both thermodynamic equilibrium and nonequilibrium conditions, and the quantum contributions are obtained by only assuming that the Lagrange multipliers can be expanded in powers of ({h_bar}/2{pi}){sup 2}. In particular, by using an arbitrary number of moments, we prove that (1) on a macroscopic scale all nonlocal effects, compatible with the uncertainty principle, are imputable to high-order spatial derivatives, both of the numerical density n and of the effective temperature T; (2) the results available from the literature in the framework of both a quantum Boltzmann gas and a degenerate quantum Fermi gas are recovered as a particular case; (3) the statistics for the quantum Fermi and Bose gases at different levels of degeneracy are explicitly incorporated; (4) a set of relevant applications admitting exact analytical equations are explicitly given and discussed; (5) the quantum maximum entropy principle keeps full validity in the classical limit, when ({h_bar}/2{pi}){yields}0.

  2. A LARGER ESTIMATE OF THE ENTROPY OF THE UNIVERSE

    SciTech Connect (OSTI)

    Egan, Chas A. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Lineweaver, Charles H., E-mail: chas@mso.anu.edu.a [Planetary Science Institute, Research School of Astronomy and Astrophysics and Research School of Earth Sciences, Australian National University, Canberra (Australia)

    2010-02-20T23:59:59.000Z

    Using recent measurements of the supermassive black hole (SMBH) mass function, we find that SMBHs are the largest contributor to the entropy of the observable universe, contributing at least an order of magnitude more entropy than previously estimated. The total entropy of the observable universe is correspondingly higher, and is S{sub obs} = 3.1{sup +3.0}{sub -1.7} x 10{sup 104} k. We calculate the entropy of the current cosmic event horizon to be S{sub CEH} = 2.6 +- 0.3 x 10{sup 122} k, dwarfing the entropy of its interior, S{sub CEH{sub int}} = 1.2{sup +1.1}{sub -0.7} x 10{sup 103} k. We make the first tentative estimate of the entropy of weakly interacting massive particle dark matter within the observable universe, S{sub dm} = 10{sup 88+}-{sup 1} k. We highlight several caveats pertaining to these estimates and make recommendations for future work.

  3. Braze alloy development for zircaloy

    SciTech Connect (OSTI)

    Donovan, A.H.

    1988-05-01T23:59:59.000Z

    The purpose of this study was to find a suitable braze alloy to close the ends of a new fuel design for N Reactor, the defense reactor at the Hanford site, Washington. An alloy composed of Zircaloy-2 + 8 wt % chromium + 8 wt % nickel (Zr2-8Cr-8Ni) was successfully used to obtain an acceptable joint with no voids. Suggestions for future work on end closure development for the new fuel are outlined. This alloy has potential use in any Zircaloy joining applications. 3 refs., 9 figs., 3 tabs.

  4. Bound for entropy and viscosity ratio for strange quark matter

    E-Print Network [OSTI]

    Manjari Bagchi; Jishnu Dey; Mira Dey; Taparati Gangopadhyay; Sibasish Laha; Subharthi Ray; Monika Sinha

    2008-07-03T23:59:59.000Z

    High energy density ($\\eps$) and temperature (T) links general relativity and hydrodynamics leading to a lower bound for the ratio of shear viscosity ($\\eta$) and entropy density ($s$). We get the interesting result that the bound is saturated in the simple model for quark matter that we use for strange stars at the surface for $T \\sim 80 MeV$. At this $T$ we have the possibility of cosmic separation of phases. At the surface of the star where the pressure is zero - the density $\\eps$ has a fixed value for all stars of various masses with correspondingly varying central energy density $\\eps_c$. Inside the star where this density is higher, the ratio of $\\eta/s$ is larger and are like the known results found for perturbative QCD. This serves as a check of our calculation. The deconfined quarks at the surface of the strange star at $T = 80 MeV$ seem to constitute the most perfect interacting fluid permitted by nature.

  5. Maximum Entropy Analysis of the Spectral Functions in Lattice QCD

    E-Print Network [OSTI]

    M. Asakawa; T. Hatsuda; Y. Nakahara

    2001-02-26T23:59:59.000Z

    First principle calculation of the QCD spectral functions (SPFs) based on the lattice QCD simulations is reviewed. Special emphasis is placed on the Bayesian inference theory and the Maximum Entropy Method (MEM), which is a useful tool to extract SPFs from the imaginary-time correlation functions numerically obtained by the Monte Carlo method. Three important aspects of MEM are (i) it does not require a priori assumptions or parametrizations of SPFs, (ii) for given data, a unique solution is obtained if it exists, and (iii) the statistical significance of the solution can be quantitatively analyzed. The ability of MEM is explicitly demonstrated by using mock data as well as lattice QCD data. When applied to lattice data, MEM correctly reproduces the low-energy resonances and shows the existence of high-energy continuum in hadronic correlation functions. This opens up various possibilities for studying hadronic properties in QCD beyond the conventional way of analyzing the lattice data. Future problems to be studied by MEM in lattice QCD are also summarized.

  6. Weak Scale From the Maximum Entropy Principle

    E-Print Network [OSTI]

    Yuta Hamada; Hikaru Kawai; Kiyoharu Kawana

    2014-09-23T23:59:59.000Z

    The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\

  7. Maximum Entropy Method Approach to $?$ Term

    E-Print Network [OSTI]

    Masahiro Imachi; Yasuhiko Shinno; Hiroshi Yoneyama

    2004-06-09T23:59:59.000Z

    In Monte Carlo simulations of lattice field theory with a $\\theta$ term, one confronts the complex weight problem, or the sign problem. This is circumvented by performing the Fourier transform of the topological charge distribution $P(Q)$. This procedure, however, causes flattening phenomenon of the free energy $f(\\theta)$, which makes study of the phase structure unfeasible. In order to treat this problem, we apply the maximum entropy method (MEM) to a Gaussian form of $P(Q)$, which serves as a good example to test whether the MEM can be applied effectively to the $\\theta$ term. We study the case with flattening as well as that without flattening. In the latter case, the results of the MEM agree with those obtained from the direct application of the Fourier transform. For the former, the MEM gives a smoother $f(\\theta)$ than that of the Fourier transform. Among various default models investigated, the images which yield the least error do not show flattening, although some others cannot be excluded given the uncertainty related to statistical error.

  8. Weak Scale From the Maximum Entropy Principle

    E-Print Network [OSTI]

    Hamada, Yuta; Kawana, Kiyoharu

    2014-01-01T23:59:59.000Z

    The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\

  9. Cu(In,Ga)Se2 alloys are the leading choice for absorber layers in high-efficiency thin film solar cells due to their direct gap, high absorption

    E-Print Network [OSTI]

    Rockett, Angus

    film solar cells due to their direct gap, high absorption coefficient and excellent thermal stability Cu(In,Ga)Se2 are used to interpret PL results. ·No evidence of band-to-band transitions (rare in CIGS

  10. High-Precision Thermodynamics and Hagedorn Density of States

    E-Print Network [OSTI]

    Harvey B. Meyer

    2009-05-26T23:59:59.000Z

    We compute the entropy density of the confined phase of QCD without quarks on the lattice to very high accuracy. The results are compared to the entropy density of free glueballs, where we include all the known glueball states below the two-particle threshold. We find that an excellent, parameter-free description of the entropy density between 0.7Tc and Tc is obtained by extending the spectrum with the exponential spectrum of the closed bosonic string.

  11. Alloying effects on mechanical and metallurgical properties of NiAl

    SciTech Connect (OSTI)

    Liu, C.T.; Horton, J.A.; Lee, E.H.; George, E.P.

    1993-06-01T23:59:59.000Z

    Alloying effects were investigated in near-stoichiometric NiAl for improving its mechanical and metallurgical properties. Ternary additions of 19 elements at levels up to 10 at. % were added to NiAl; among them, molybdenum is found to be most effective in improving the room-temperature ductility and high-temperature strength. Alloying with 1.0 {plus_minus} 0.6% molybdenum almost doubles the room-temperature tensile ductility of NiAl and triples its yield strength at 1000C. The creep properties of molybdenum-modified NiAl alloys can be dramatically improved by alloying with up to 1% of niobium or tantalum. Because of the low solubilities of molybdenum and niobium in NiAl, the beneficial effects mainly come from precipitation hardening. Fine and coarse precipitates are revealed by both transmission electron microscopy (TEM) and electron microprobe analyses. Molybdenum-containing alloys possess excellent oxidation resistance and can be fabricated into rod stock by hot extrusion at 900 to 1050C. This study of alloying effects provides a critical input for the alloy design of ductile and strong NiAl aluminide alloys for high-temperature structural applications.

  12. High Energy Novel Cathode / Alloy Automotive Cell

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  13. Highly Mismatched Semiconductor Alloys with Extreme Compositions

    E-Print Network [OSTI]

    Levander, Alejandro X.

    2012-01-01T23:59:59.000Z

    mol% n n N N N N As N I ? D PLM PLA PR q r r R e r-space RBSN whereas an optimized PLM treatment results in ~0.8 mol%N incorporated into GaAs from a PLM or RTA process. As the

  14. Highly Mismatched Semiconductor Alloys with Extreme Compositions

    E-Print Network [OSTI]

    Levander, Alejandro X.

    2012-01-01T23:59:59.000Z

    epitaxy on c-sapphire substrates with a GaN buffer layer (film of a-GaN 0.55 As 0.45 on a glass substrate at the As Kfilm of a-GaN 0.55 As 0.45 on a glass substrate at the As K

  15. The Effect of Cold Work on Properties of Alloy 617

    SciTech Connect (OSTI)

    Richard Wright

    2014-08-01T23:59:59.000Z

    Alloy 617 is approved for non-nuclear construction in the ASME Boiler and Pressure Vessel Code Section I and Section VIII, but is not currently qualified for nuclear use in ASME Code Section III. A draft Code Case was submitted in 1992 to qualify the alloy for nuclear service but efforts were stopped before the approval process was completed.1 Renewed interest in high temperature nuclear reactors has resulted in a new effort to qualify Alloy 617 for use in nuclear pressure vessels. The mechanical and physical properties of Alloy 617 were extensively characterized for the VHTR programs in the 1980’s and incorporated into the 1992 draft Code Case. Recently, the properties of modern heats of the alloy that incorporate an additional processing step, electro-slag re-melting, have been characterized both to confirm that the properties of contemporary material are consistent with those in the historical record and to increase the available database. A number of potential issues that were identified as requiring further consideration prior to the withdrawal of the 1992 Code Case are also being re-examined in the current R&D program. Code Cases are again being developed to allow use of Alloy 617 for nuclear design within the rules of the ASME Boiler and Pressure Vessel Code. In general the Code defines two temperature ranges for nuclear design with austenitic and nickel based alloys. Below 427°C (800°F) time dependent behavior is not considered, while above this temperature creep and creep-fatigue are considered to be the dominant life-limiting deformation modes. There is a corresponding differentiation in the treatment of the potential for effects associated with cold work. Below 427°C the principal issue is the relationship between the level of cold work and the propensity for stress corrosion cracking and above that temperature the primary concern is the impact of cold work on creep-rupture behavior.

  16. Hydrogen decreased ductility of a U-6%NB alloy.

    SciTech Connect (OSTI)

    Teter, D. F. (David F.); Hackenberg, R. E. (Robert E.); Mauro, M. E. (Michael Ernest); McCabe, R. J. (Rodney J.); Dickerson, P. O. (Patricia O.)

    2004-01-01T23:59:59.000Z

    Hydrogen decreases the ductility of uranium alloys without resulting in a brittle failure. Due to the low solubility of hydrogen and the propensity to form hydrides in uranium and its alloys, it might be expected that the mechanism of embrittlement would be the stress-induced hydride formation and cleavage mechanism. However at 2-5 wppm levels, hydrogen significantly decreases the ductility of the alloy without resulting in a cleavage-based mechanism. We have chosen the uranium-niobium (6wt.%) alloy system to investigate the hydrogen embrittlement phenomena in uranium-based alloys. The alloy was gas - phase charged at 800 C at pressures ranging from 10{sup -4} to 10{sup -1} MPa using ultra-high purity hydrogen gas (99.999%) followed by water quenching. Hydrogen contents ranged from 0 wppm (vacuum outgassed) to 20 wppm. Tensile tests were performed at strain rates of 10{sup -3} and 10{sup -5} sec{sup -1}. The elongation and reduction in area decrease rapidly from 0 wppm to 5 wppm with little further reduction at 20 wppm. Hydrogen has no effect on the yield strength, ultimate tensile strength and work hardening coefficient. Scanning electron microscopy of the fracture surfaces shows that all of the samples fail by ductile microvoid coalescence. Concomitant with the reduction in ductility due to increased hydrogen content, the micro void size also decreases with increasing hydrogen content. This alloy has numerous inclusions and the microvoids all nucleate at the inclusions. At low hydrogen contents, the microvoids appear to nucleate only on the largest inclusions ({approx}10 {mu}m). As the hydrogen content increases, the microvoids tend to also nucleate on smaller inclusions (< 1 {mu}m). Hydrogen appears to be decreasing the inclusion/metal interface strength of the smaller inclusions and localizing deformation near the debonded inclusion. Since many more microvoid nuclei are active due to hydrogen, the microvoids link together and cause fracture at a lower overall macroscopic strain.

  17. [MRO] Oligocrystalline Shape Memory Alloys

    E-Print Network [OSTI]

    Chen, Ying

    Copper-based shape memory alloys (SMAs) exhibit excellent shape memory properties in single crystalline form. However, when they are polycrystalline, their shape memory properties are severely compromised by brittle fracture ...

  18. Design of Stable Nanocrystalline Alloys

    E-Print Network [OSTI]

    Chookajorn, Tongjai

    Nanostructured metals are generally unstable; their grains grow rapidly even at low temperatures, rendering them difficult to process and often unsuitable for usage. Alloying has been found to improve stability, but only ...

  19. Shape memory alloy thaw sensors

    DOE Patents [OSTI]

    Shahinpoor, M.; Martinez, D.R.

    1998-04-07T23:59:59.000Z

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states. 16 figs.

  20. Characterization of Shape Memory Alloys Using Artificial Neural Networks

    E-Print Network [OSTI]

    Valasek, John

    1 Characterization of Shape Memory Alloys Using Artificial Neural Networks Jim Henrickson, Kenton ­ Shape Memory Alloys ­ Artificial Neural Networks Process ­ Implement Shape Memory Alloy Model;3 Introduction Shape memory alloys (SMAs) ­ Active material: material that undergoes macroscopic change

  1. Pulsed electrodeposition of iron-nickel alloys

    SciTech Connect (OSTI)

    Grimmett, D.L.; Schwartz, M.; Nobe, K. (Dept. of Chemical Engineering, Univ. of California, Los Angeles, CA (US))

    1990-11-01T23:59:59.000Z

    This paper reports on the effects of dc, pulse, and pulse reverse current waveforms on deposition of Fe-Ni alloys studied in unagitated solutions and with a rotating cylindrical electrode. A nickel sulfamate/ferrous chloride electrolyte system at pH 2 less than 2 A/dm{sup 2}. Pulse reverse plating led to a decrease in anomalous deposition at low current densities. Rotating cylindrical electrodes indicated significant mass transfer effects at high current densities. During pulse reverse plating an increase in anodic pulse magnitude decreased anomalous deposition; pulse frequency had its greatest effect in reducing anomalous deposition between 100 and 300 Hz.

  2. Physical and mechanical metallurgy of uranium and uranium alloys

    SciTech Connect (OSTI)

    Eckelmeyer, K.H. [Sandia National Labs. (United States)

    1998-12-31T23:59:59.000Z

    Engineering disadvantages of unalloyed uranium include relatively low strength, low ductility, and poor oxidation and corrosion resistance. As-cast uranium typically exhibits very large grains that cause nonuniform deformation and low tensile ductility. Uranium is often alloyed to improve its corrosion resistance and mechanical properties. Titanium is most commonly used to increase strength; niobium and molybdenum, to increase oxidation and corrosion resistance; and vanadium, to refine alpha grain size in castings. Under equilibrium conditions these elements are extensively soluble in the high-temperature gamma phase, slightly soluble in the intermediate temperature beta phase, and essentially insoluble in the low-temperature alpha phase. Uranium alloys are vacuum solution heat treated in the gamma range to dissolve the alloying elements and remove hydrogen. The subsequent microstructures and properties are determined by the cooling rate from the solution treatment temperature. Oxidation and corrosion resistance increases with increasing the amount of alloy in solid solution. As a result, alloys such as U-6%Nb and U-10%Mo are often used in applications requiring good corrosion resistance.

  3. Evaluation of Quasicrystal Al-Cu-Fe Alloys for Tribological Applications 

    E-Print Network [OSTI]

    Nabelsi, Nezar

    2013-07-22T23:59:59.000Z

    This research investigated the tribological performance of a composite material, formed from an ultra high molecular weight polyethylene (UHMWPE) matrix and quasicrystalline Al-Cu-Fe alloy powders. An evaluation was conducted for the microstructure...

  4. Amorphous Al-transition Metal Alloys as Anode Material for Lithium Ion Battery

    E-Print Network [OSTI]

    Wang, C.Y.

    Al based alloy powders (Al??Ni?Y?Co?Fe?) are produced by spray atomization method. High energy ball milling is done to modify the surface topology and particle size for better electrochemical performance. X ray diffraction ...

  5. Low-temperature solution synthesis of alloys and intermetallic compounds as nanocrystals 

    E-Print Network [OSTI]

    Vasquez, Yolanda

    2009-05-15T23:59:59.000Z

    the rate of reaction between two solids; however, the high temperatures required to overcome the diffusion barrier limit the products accessible to the most thermodynamically stable phases. In this work, nano-scale solids such as alloys and intermetallics...

  6. Thermomechanical behavior at the nanoscale and size effects in shape memory alloys

    E-Print Network [OSTI]

    San Juan, Jose

    Shape memory alloys (SMA) undergo reversible martensitic transformation in response to changes in temperature or applied stress, resulting in the properties of superelasticity and shape memory. At present, there is high ...

  7. Hard and tough electrodeposited aluminum-manganese alloys with tailored nanostructures

    E-Print Network [OSTI]

    Ruan, Shiyun

    2010-01-01T23:59:59.000Z

    Tailoring the nanostructure of electrodeposited Al-Mn films to achieve high hardness and toughness is the overarching goal of this thesis. Binary Al-Mn alloys are electrodeposited using a conventional current waveform in ...

  8. Evaluation of Quasicrystal Al-Cu-Fe Alloys for Tribological Applications

    E-Print Network [OSTI]

    Nabelsi, Nezar

    2013-07-22T23:59:59.000Z

    This research investigated the tribological performance of a composite material, formed from an ultra high molecular weight polyethylene (UHMWPE) matrix and quasicrystalline Al-Cu-Fe alloy powders. An evaluation was conducted for the microstructure...

  9. Stress corrosion cracking and crack tip characterization of Alloy X-750 in light water reactor environments

    E-Print Network [OSTI]

    Gibbs, Jonathan Paul

    2011-01-01T23:59:59.000Z

    Stress corrosion cracking (SCC) susceptibility of Inconel Alloy X-750 in the HTH condition has been evaluated in high purity water at 93 and 288°C under Boiling Water Reactor Normal Water Chemistry (NWC) and Hydrogen Water ...

  10. Stress Corrosion Cracking and Crack Tip Characterization of Alloy X-750 in Light Water Reactor Environments

    E-Print Network [OSTI]

    Gibbs, Jonathan Paul

    Stress corrosion cracking (SCC) susceptibility of Inconel Alloy X-750 in the HTH condition has been evaluated in high purity water at 93 and 288°C under Boiling Water Reactor Normal Water Chemistry (NWC) and Hydrogen Water ...

  11. aluminium alloys aa2024-t351: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  12. aluminium 6060-t5 alloys: Topics by E-print Network

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

    samples were prepared from high purity aluminium (99.9%) powder Gubicza, Jen 5 Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds. Open Access...

  13. Cladding Alloys for Fluoride Salt Compatibility

    SciTech Connect (OSTI)

    Muralidharan, Govindarajan [ORNL; Wilson, Dane F [ORNL; Walker, Larry R [ORNL; Santella, Michael L [ORNL; Holcomb, David Eugene [ORNL

    2011-06-01T23:59:59.000Z

    This report provides an overview of several candidate technologies for cladding nickel-based corrosion protection layers onto high-temperature structural alloys. The report also provides a brief overview of the welding and weld performance issues associated with joining nickel-clad nickel-based alloys. From the available techniques, two cladding technologies were selected for initial evaluation. The first technique is a line-of-sight method that would be useful for cladding large structures such as vessel interiors or large piping. The line-of-sight method is a laser-based surface cladding technique in which a high-purity nickel powder mixed into a polymer binder is first sprayed onto the surface, baked, and then rapidly melted using a high-power laser. The second technique is a vapor phase technique based on the nickel-carbonyl process that is suitable for cladding inaccessible surfaces such as the interior surfaces of heat exchangers. An initial evaluation for performed on the quality of nickel claddings processed using the two selected cladding techniques.

  14. Liquid-Solid Phase Transition Alloy as Reversible and Rapid Molding Bone Cement

    E-Print Network [OSTI]

    Yi, Liting; Liu, Jing

    2013-01-01T23:59:59.000Z

    Bone cement has been demonstrated as an essential restorative material in the orthopedic surgery. However current materials often imply unavoidable drawbacks, such as tissue-cement reaction induced thermal injuries and troublesome revision procedure. Here we proposed an injectable alloy cement to address such problems through its liquid-solid phase transition mechanism. The cement is made of a unique alloy BiInSnZn with a specifically designed low melting point 57.5{\\deg}C. This property enables its rapid molding into various shapes with high plasticity. Some fundamental characteristics including mechanical strength behaviors and phase transition-induced thermal features have been measured to demonstrate the competence of alloy as unconventional cement with favorable merits. Further biocompatible tests showed that this material could be safely employed in vivo. In addition, experiments also found the alloy cement capability as an excellent contrast agent for radiation imaging. Particularly, the proposed alloy...

  15. On the Relation Between Oxide Ridge Evolution and Alloy Surface Grain Boundary Disorientation in Fe22 wt % Cr Alloys

    E-Print Network [OSTI]

    Laughlin, David E.

    high temperature corrosion or oxidation can lead to the failure of the cell. Also, volatile CrO3 andOn the Relation Between Oxide Ridge Evolution and Alloy Surface Grain Boundary Disorientation in Fe Technology Laboratory, Albany, Oregon 97321-2198, USA Oxide ridges formed during the transient stage

  16. Modular Process Equipment for Low Cost Manufacturing of High...

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

    Process Equipment for Low Cost Manufacturing of High Capacity Prismatic Li-Ion Cell Alloy Anodes Modular Process Equipment for Low Cost Manufacturing of High Capacity Prismatic...

  17. Material synthesis and hydrogen storage of palladium-rhodium alloy.

    SciTech Connect (OSTI)

    Lavernia, Enrique J. (University of California, Davis); Yang, Nancy Y. C.; Ong, Markus D. (Whithworth University, Spokane, WA)

    2011-08-01T23:59:59.000Z

    Pd and Pd alloys are candidate material systems for Tr or H storage. We have actively engaged in material synthesis and studied the material science of hydrogen storage for Pd-Rh alloys. In collaboration with UC Davis, we successfully developed/optimized a supersonic gas atomization system, including its processing parameters, for Pd-Rh-based alloy powders. This optimized system and processing enable us to produce {le} 50-{mu}m powders with suitable metallurgical properties for H-storage R&D. In addition, we studied hydrogen absorption-desorption pressure-composition-temperature (PCT) behavior using these gas-atomized Pd-Rh alloy powders. The study shows that the pressure-composition-temperature (PCT) behavior of Pd-Rh alloys is strongly influenced by its metallurgy. The plateau pressure, slope, and H/metal capacity are highly dependent on alloy composition and its chemical distribution. For the gas-atomized Pd-10 wt% Rh, the absorption plateau pressure is relatively high and consistent. However, the absorption-desorption PCT exhibits a significant hysteresis loop that is not seen from the 30-nm nanopowders produced by chemical precipitation. In addition, we observed that the presence of hydrogen introduces strong lattice strain, plastic deformation, and dislocation networking that lead to material hardening, lattice distortions, and volume expansion. The above observations suggest that the H-induced dislocation networking is responsible for the hysteresis loop seen in the current atomized Pd-10 wt% Rh powders. This conclusion is consistent with the hypothesis suggested by Flanagan and others (Ref 1) that plastic deformation or dislocations control the hysteresis loop.

  18. Corrosion of metals and alloys : anodic test for evaluation of intergranular corrosion susceptibility of heat-treatable aluminium alloys

    E-Print Network [OSTI]

    International Organization for Standardization. Geneva

    2006-01-01T23:59:59.000Z

    Corrosion of metals and alloys : anodic test for evaluation of intergranular corrosion susceptibility of heat-treatable aluminium alloys

  19. CREEP AND CREEP-FATIGUE OF ALLOY 617 WELDMENTS

    SciTech Connect (OSTI)

    Wright, Jill; Carroll, Laura; Wright, Richard

    2014-08-01T23:59:59.000Z

    The Very High Temperature Reactor (VHTR) Intermediate Heat Exchanger (IHX) may be joined to piping or other components by welding. Creep-fatigue deformation is expected to be a predominant failure mechanism of the IHX1 and thus weldments used in its fabrication will experience varying cyclic stresses interrupted by periods of elevated temperature deformation. These periods of elevated temperature deformation are greatly influenced by a materials’ creep behavior. The nickel-base solid solution strengthened alloy, Alloy 617, is the primary material candidate for a VHTR-type IHX, and it is expected that Alloy 617 filler metal will be used for welds. Alloy 617 is not yet been integrated into Section III of the Boiler and Pressure Vessel Code, however, nuclear component design with Alloy 617 requires ASME (American Society of Mechanical Engineers) Code qualification. The Code will dictate design for welded construction through significant performance reductions. Despite the similar compositions of the weldment and base material, significantly different microstructures and mechanical properties are inevitable. Experience of nickel alloy welds in structural applications suggests that most high temperature failures occur at the weldments or in the heat-affected zone. Reliably guarding against this type of failure is particularly challenging at high temperatures due to the variations in the inelastic response of the constituent parts of the weldment (i.e., weld metal, heat-affected zone, and base metal) [ref]. This work focuses on the creep-fatigue behavior of nickel-based weldments, a need noted during the development of the draft Alloy 617 ASME Code Case. An understanding of Alloy 617 weldments when subjected to this important deformation mode will enable determination of the appropriate design parameters associated with their use. Specifically, the three main areas emphasized are the performance reduction due to a weld discontinuity in terms of the reduced number of the cycles to failure and whether a saturation in reduced cycle life with increased hold times is observed, the microstructural stability over long cycle times, and finally, the location of the generated weldment data on a creep-fatigue damage diagram (D-diagram).

  20. Directly observing entropy accumulate on the horizon and holography

    E-Print Network [OSTI]

    Ariel Edery; Hugues Beauchesne

    2012-05-15T23:59:59.000Z

    Recent numerical simulations of gravitational collapse show that there exists a special foliation of the spacetime where matter and entropy accumulate directly on the inside of the horizon surface. In this foliation, the time coincides with the proper time of the asymptotic static observer (ASO) and for spherical symmetry, this corresponds to isotropic coordinates. In this gauge, the three-volume in the interior shrinks to zero and only the horizon area remains at the end of collapse. In a different foliation, matter and entropy accumulate in the volume. The entropy is however independent of the foliation. Black hole holography is therefore a mapping from an arbitrary foliation, where information resides in the volume, to the special ASO frame, where it resides directly on the horizon surface.