National Library of Energy BETA

Sample records for high entropy alloy

  1. Laser assisted high entropy alloy coating on aluminum: Microstructural evolution

    SciTech Connect (OSTI)

    Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B.

    2014-09-14

    High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

  2. Experiments and Model for Serration Statistics in Low-Entropy, Medium-Entropy, and High-Entropy Alloys

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

    Carroll, Robert; Lee, Chi; Tsai, Che-Wei; Yeh, Jien-Wei; Antonaglia, James; Brinkman, Braden A.W.; LeBlanc, Michael; Xie, Xie; Chen, Shuying; Liaw, Peter K; et al

    2015-11-23

    High-entropy alloys (HEAs) are new alloys that contain five or more elements in roughly equal proportion. We present new experiments and theory on the deformation behavior of HEAs under slow stretching (straining), and observe differences, compared to conventional alloys with fewer elements. For a specific range of temperatures and strain-rates, HEAs deform in a jerky way, with sudden slips that make it difficult to precisely control the deformation. An analytic model explains these slips as avalanches of slipping weak spots and predicts the observed slip statistics, stress-strain curves, and their dependence on temperature, strain-rate, and material composition. The ratio ofmore »the weak spots’ healing rate to the strain-rate is the main tuning parameter, reminiscent of the Portevin-LeChatellier effect and time-temperature superposition in polymers. Our model predictions agree with the experimental results. The proposed widely-applicable deformation mechanism is useful for deformation control and alloys design.« less

  3. Precipitation in the Equiatomic High-Entropy Alloy CrMnFeCoNi

    E-Print Network [OSTI]

    Pickering, E. J.; Muñoz-Moreno, R.; Stone, H. J.; Jones, N. G.

    2015-11-02

    CrMnFeCoNi is widely considered to be an exemplar high-entropy alloy, which is stable as a single solid-solution phase at all temperatures below its melting point. Here, for the first time, the formation of two distinct types of Cr-rich precipitate...

  4. Local structures of high-entropy alloys (HEAs) on atomic scales: An overview

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

    Diao, Haoyan; Santodonato, Louis J.; Tang, Zhi; Egami, Takeshi; Liaw, Peter K.

    2015-08-29

    The high-entropy alloys, containing several elements mixed in equimolar or near-equimolar ratios, have shown exceptional engineering properties. Local structures on the atomic level are essential to understand the mechanical behaviors and related mechanisms. This article covers the local structure and stress on the atomic level are reviewed by the pair-distribution function of neutron-diffraction data, ab-initio molecular dynamics simulations, and the atomic probe microscopy.

  5. Local electronic effects and irradiation resistance in high-entropy alloys

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

    Egami, Takeshi; Stocks, George Malcolm; Nicholson, Don; Khorgolkhuu, Od; Ojha, Madhusudan

    2015-01-01

    High-entropy alloys are multicomponent solid solutions in which various elements with different chemistries and sizes occupy the same crystallographic lattice sites. Thus, none of the atoms perfectly fit the lattice site, giving rise to considerable local lattice distortions and atomic-level stresses. These characteristics can be beneficial for performance under both radiation and in a high-temperature environment, making them attractive candidates as nuclear materials. We discuss electronic origin of the atomic-level stresses based upon first-principles calculations using a density functional theory approach.

  6. Deviation from high-entropy configurations in the atomic distributions of a multi-principal-element alloy

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

    Santodonato, Louis J.; Zhang, Yang; Feygenson, Mikhail; Parish, Chad M.; Gao, Michael C.; Weber, Richard J. K.; Neuefeind, Joerg C.; Tang, Zhi; Liaw, Peter K.

    2015-01-20

    The alloy-design strategy of combining multiple elements in near-equimolar ratios has shown great potential for producing exceptional engineering materials, often known as “high-entropy alloys”. Understanding the elemental distribution, and, thus, the evolution of the configurational entropy during solidification, is undertaken in the present study using the Al1.3CoCrCuFeNi model alloy. Here we show that even when the material undergoes elemental segregation, precipitation, chemical ordering, and spinodal decomposition, a significant amount of disorder remains, due to the distributions of multiple elements in the major phases. In addition, the results suggest that the high-entropy-alloy-design strategy may be applied to a wide range ofmore »complex materials, and should not be limited to the goal of creating single-phase solid solutions.« less

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

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

    An, Zhinan; Jia, Haoling; Wu, Yueying; Rack, Philip D.; Patchen, Allan D.; Liu, Yuzi; Ren, Yang; Li, Nan; Liaw, Peter K.

    2015-05-04

    The concept of high configurational entropy requires that the high-entropy alloys (HEAs) yield single-phase solid solutions. However, phase separations are quite common in bulk HEAs. A five-element alloy, CrCoCuFeNi, was deposited via radio frequency magnetron sputtering and confirmed to be a single-phase solid solution through the high-energy synchrotron X-ray diffraction, energy-dispersive spectroscopy, wavelength-dispersive spectroscopy, and transmission electron microscopy. The formation of the solid-solution phase is presumed to be due to the high cooling rate of the sputter-deposition process.

  8. Temperature effects on deformation and serration behavior of high-entropy alloys (HEAs)

    SciTech Connect (OSTI)

    Antonaglia, J.; Xie, X.; Tang, Z.; Tsai, C. -W.; Qiao, J. W.; Zhang, Y.; Laktionova, M. O.; Tabachnikova, E. D.; Yeh, J. W.; Senkov, O. N.; Gao, M. C.; Uhl, J. T.; Liaw, P. K.; Dahmen, K. A.

    2014-09-16

    Many materials are known to deform under shear in an intermittent way with slip avalanches detected as acoustic emission and serrations in the stress–strain curves. Similar serrations have recently been observed in a new class of materials, called high-entropy alloys (HEAs). Here, we discuss the serration behaviors of several HEAs from cryogenic to elevated temperatures. The experimental results of slow compression and tension tests are compared with the predictions of a slip-avalanche model for the deformation of a broad range of solids. The results shed light on the deformation processes in HEAs. Temperature effects on the distributions of stress drops and the decrease of the cutoff (i.e., of the largest observed slip size) for increasing temperature qualitatively agree with the model predictions. As a result, the model is used to quantify the serration characteristics of HEAs, and pertinent implications are discussed.

  9. Temperature effects on deformation and serration behavior of high-entropy alloys (HEAs)

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

    Antonaglia, J.; Xie, X.; Tang, Z.; Tsai, C. -W.; Qiao, J. W.; Zhang, Y.; Laktionova, M. O.; Tabachnikova, E. D.; Yeh, J. W.; Senkov, O. N.; et al

    2014-09-16

    Many materials are known to deform under shear in an intermittent way with slip avalanches detected as acoustic emission and serrations in the stress–strain curves. Similar serrations have recently been observed in a new class of materials, called high-entropy alloys (HEAs). Here, we discuss the serration behaviors of several HEAs from cryogenic to elevated temperatures. The experimental results of slow compression and tension tests are compared with the predictions of a slip-avalanche model for the deformation of a broad range of solids. The results shed light on the deformation processes in HEAs. Temperature effects on the distributions of stress dropsmore »and the decrease of the cutoff (i.e., of the largest observed slip size) for increasing temperature qualitatively agree with the model predictions. As a result, the model is used to quantify the serration characteristics of HEAs, and pertinent implications are discussed.« less

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

    E-Print Network [OSTI]

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

    2015-02-03

    , sluggish. 9 Acknowledgements: The authors would like to acknowledge support from the EPSRC / Rolls-Royce Strategic Partnership under EP/H500375/1, EP/M005607/1 (NGJ & HJS) and EP/H022309/1 (KAC). References: 1. J. Yeh, S. Chen, S. Lin, J. Gan, T... and Wear Resistance for Thermal Spray Coating', Advanced Engineering Materials, 2004, 6(12), 74-78. 11. Y. Chen, T. Duval, U. Hung, J. Yeh, and H. Shih: 'Microstructure and electrochemical properties of high entropy alloys - a comparison with type-304...

  11. A Successful Synthesis of the CoCrFeNiAl{sub 0.3} Single-Crystal, High-Entropy Alloy by Bridgman Solidification

    SciTech Connect (OSTI)

    Ma, S. G.; Zhang, S. F.; Gao, M. C.; Liaw, P. K.; Zhang, Y.

    2013-12-01

    For the first time, a face-centered-cubic, single-crystal CoCrFeNiAl{sub 0.3} (designated as Al0.3), high-entropy alloy (HEA) was successfully synthesized by the Bridgman solidification (BS) method, at an extremely low withdrawal velocity through a constant temperature gradient, for which it underwent two BS steps. Specially, at the first BS step, the alloy sample underwent several morphological transitions accompanying the crystal growth from the melt. This microstructure evolves from as-cast dendrites, to equiaxed grains, and then to columnar crystals, and last to the single crystal. In particular, at the equiaxed-grain region, some visible annealing twins were observed, which indicates a low stacking fault energy of the Al0.3 alloy. Although a body-centered- cubic CoCrFeNiAl (Al1) HEA was also prepared under the same conditions, only a single columnar-crystal structure with instinctively preferential crystallographic orientations was obtained by the same procedure. A similar morphological transition from dendrites to equiaxed grains occurred at the equiaxed-grain region in Al1 alloy, but the annealing twins were not observed probably because a higher Al addition leads to a higher stacking fault energy for this alloy.

  12. Effects of temperature on serrated flows of Al0.5CoCrCuFeNi high-entropy alloy

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

    Chen, Shuying; Xie, Xie; Chen, Bilin; Qiao, Junwei; Zhang, Yong; Ren, Yang; Dahmen, Karin A.; Liaw, Peter K.

    2015-08-14

    Compression behavior of the Al0.5CoCrCuFeNi high-entropy alloy (HEA) was studied at different temperatures from 673K to 873K at a low strain rate of 5 x 10-5/s to investigate the temperature effect on the mechanical properties and serration behavior. The face-centered cubic (FCC) structure is confirmed at the lower temperature of 673 K and 773 K, and a structure of mixed FCC and body-centered cubic (BCC) is identified at a higher temperature of 873 K after compression tests using high-energy synchrotron X-ray diffraction. As a result, by comparing the stress-strain curves at different temperatures, two opposite directions of serrations types weremore »found, named upward serrations appearing at 673 K and 773 K and downward serrations at 873 K, which may be due to dynamic strain aging.« less

  13. 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

    2012-06-05

    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.

  14. 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

    2010-08-31

    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.

  15. Influence of Bridgman solidification on microstructures and magnetic behaviors of a non-equiatomic FeCoNiAlSi high-entropy alloy

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

    Zuo, Tingting; Yang, Xiao; Liaw, Peter K.; Zhang, Yong

    2015-09-07

    The non-equiatomic FeCoNiAlSi alloy is prepared by the Bridgman solidification (BS) technique at different withdrawal velocities (V = 30, 100, and 200 ?m/s). Various characterization techniques have been used to study the microstructure and crystal orientation. The morphological evolutions accompanying the crystal growth of the alloy prepared at different withdrawal velocities are nearly the same, from equiaxed grains to columnar crystals. The transition of coercivity is closely related to the local microstructure, while the saturation magnetization changes little at different sites. The coercivity can be significantly reduced from the equiaxed grain area to the columnar crystal area when the appliedmore »magnetic field direction is parallel to the crystal growth direction, no matter what is the withdrawal velocity. As a result, the alloy possesses magnetic anisotropy when the applied magnetic field is in different directions.« less

  16. Development of Austenitic ODS Strengthened Alloys for Very High...

    Office of Scientific and Technical Information (OSTI)

    Alloys for Very High Temperature Applications Citation Details In-Document Search Title: Development of Austenitic ODS Strengthened Alloys for Very High Temperature Applications...

  17. Holographic Calculation for Large Interval Rényi Entropy at High Temperature

    E-Print Network [OSTI]

    Bin Chen; Jie-qiang Wu

    2015-06-10

    In this paper, we study the holographic R\\'enyi entropy of a large interval on a circle at high temperature for the two-dimensional CFT dual to pure AdS$_3$ gravity. In the field theory, the R\\'enyi entropy is encoded in the CFT partition function on $n$-sheeted torus connected with each other by a large branch cut. As proposed in 1412.0763, the effective way to read the entropy in the large interval limit is to insert a complete set of state bases of the twist sector at the branch cut. Then the calculation transforms into an expansion of four-point functions in the twist sector with respect to $e^{-\\frac{2\\pi TR}{n}}$. By using the operator product expansion of the twist operators at the branch points, we read the first few terms of the R\\'enyi entropy, including the leading and next-leading contributions in the large central charge limit. Moreover, we show that the leading contribution is actually captured by the twist vacuum module. In this case by the Ward identity the four-point functions can be derived from the correlation function of four twist operators, which is related to double interval entanglement entropy. Holographically, we apply the recipe in 1303.7221 and 1306.4682 to compute the classical R\\'enyi entropy and its 1-loop quantum correction, after imposing a new set of monodromy conditions. The holographic classical result matches exactly with the leading contribution in the field theory up to $e^{-4\\pi TR}$ and $l^6$, while the holographical 1-loop contribution is in exact agreement with next-leading results in field theory up to $e^{-\\frac{6\\pi TR}{n}}$ and $l^4$ as well.

  18. An Integrated Study of a Novel Thermal Coating for Nb-Based High Temperature Alloy

    SciTech Connect (OSTI)

    Yang, Shizhong

    2015-01-31

    This report summarizes our recent works of ab initio density functional theory (DFT) method and molecular dynamics (MD) simulation on the interfaces between niobium substrate and coatings at atomic level. Potential oxidation barrier bond coat, Nb?AlC and high entropy alloys, and top coat candidates were synthesized, characterized, and evaluated in our labs. The simulation methods, experimental validation techniques, achievements already reached, students and postdoc training, and future improvement are briefly introduced.

  19. Entropy Production at High Energy and mu_B

    E-Print Network [OSTI]

    Peter Steinberg

    2007-02-08

    The systematics of bulk entropy production in experimental data on A+A, p+p and e+e- interactions at high energies and large mu_B is discussed. It is proposed that scenarios with very early thermalization, such as Landau's hydrodynamical model, capture several essential features of the experimental results. It is also pointed out that the dynamics of systems which reach the hydrodynamic regime give similar multiplicities and angular distributions as those calculated in weak-coupling approximations (e.g. pQCD) over a wide range of beam energies. Finally, it is shown that the dynamics of baryon stopping are relevant to the physics of total entropy production, explaining why A+A and e+e- multiplicities are different at low beam energies.

  20. Highly Mismatched Semiconductor Alloys with Extreme Compositions

    E-Print Network [OSTI]

    Levander, Alejandro X.

    2012-01-01

    A. , Properties of Advanced Semiconductor Materials GaN,Semiconductor alloying is a common method for tailoring material propertiesSemiconductor alloying is a common method for tailoring material properties

  1. 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)

    1990-01-01

    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.

  2. 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)

    1991-01-01

    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.

  3. Ductile aluminide alloys for high temperature applications

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN); Stiegler, James O. (Lenoir City, TN)

    1986-01-01

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

  4. Friction Stir Welding High Strength Low Alloy Steel using a Multilayer...

    Office of Scientific and Technical Information (OSTI)

    Friction Stir Welding High Strength Low Alloy Steel using a Multilayer Approach Citation Details In-Document Search Title: Friction Stir Welding High Strength Low Alloy Steel using...

  5. 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, ...

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

    DOE Patents [OSTI]

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

    1990-01-01

    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.

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

    DOE Patents [OSTI]

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

    1990-10-09

    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.

  8. High temperature seal for joining ceramics and metal alloys

    DOE Patents [OSTI]

    Maiya, P. Subraya (Darien, IL); Picciolo, John J. (Lockport, IL); Emerson, James E. (Plainfield, IL); Dusek, Joseph T. (Lombard, IL); Balachandran, Uthamalingam (Hinsdale, IL)

    1998-01-01

    For a combination of a membrane of SrFeCo.sub.0.5 O.sub.x and an Inconel alloy, a high-temperature seal is formed between the membrane and the alloy. The seal is interposed between the alloy and the membrane, and is a fritted compound of Sr oxide and boric oxide and a fritted compound of Sr, Fe and Co oxides. The fritted compound of SrFeCo.sub.0.50 O.sub.x is present in the range of from about 30 to 70 percent by weight of the total sealant material and the fritted compound of Sr oxide and boric oxide has a mole ratio of 2 moles of the Sr oxide for each mole of boric oxide. A method of sealing a ceramic to an Inconel metal alloy is also disclosed.

  9. Improved high temperature creep resistant austenitic alloy

    DOE Patents [OSTI]

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

    1988-05-13

    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.

  10. High temperature creep resistant austenitic alloy

    DOE Patents [OSTI]

    Maziasz, Philip J. (Oak Ridge, TN); Swindeman, Robert W. (Oak Ridge, TN); Goodwin, Gene M. (Lenoir City, TN)

    1989-01-01

    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.degree.-1200.degree. C. and then cold deforming 5-15 %. The alloy exhibits dramatically improved creep rupture resistance and ductility at 700.degree. C.

  11. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    SciTech Connect (OSTI)

    Coulter, K

    2013-09-30

    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.

  12. Feeding and Risering of High Alloy Steel Castings

    E-Print Network [OSTI]

    Beckermann, Christoph

    Feeding and Risering of High Alloy Steel Castings Kent D. Carlson, Shouzhu Ou and Christoph radiographically sound castings at 2 pct sensitivity. By comparing results between plate casting trials known as the Niyama criterion and ASTM shrinkage x-ray level. This relationship was then used

  13. 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)

    2000-02-01

    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.

  14. 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

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

    E-Print Network [OSTI]

    Beckermann, Christoph

    is established for all but the CZ-100 alloy, which does not appear to suffer from shrinkage defects. A large compositions (both C&LA and high-alloy steels), sand mold materials, and pouring superheats. These new rules

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

    E-Print Network [OSTI]

    Liew, Heng Lee Henry

    2008-01-01

    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 ...

  17. ITP Metal Casting: Corrosion Testing Practices ? High Alloy...

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

    AL Atlas Casting & Technology Tacoma, WA Southern Alloy Corp. Sylacauga, AL Stainless Foundry & Eng. Milwaukee, WI Wollaston Alloys Braintree, MA A Strong Energy Portfolio for a...

  18. Cermet anode compositions with high content alloy phase

    DOE Patents [OSTI]

    Marschman, S.C.; Davis, N.C.

    1989-10-03

    Cermet electrode compositions comprising NiO-NiFe[sub 2]O[sub 4]-Cu-Ni, and methods for making, are disclosed. Addition of nickel metal prior to formation and densification of a base mixture into the cermet allows for an increase in the total amount of copper and nickel that can be contained in the NiO-NiFe[sub 2]O[sub 4] oxide system. Nickel is present in a base mixture weight concentration of from 0.1% to 10%. Copper is present in the alloy phase in a weight concentration of from 10% to 30% of the densified composition. Such cermet electrodes can be formed to have electrical conductivities well in excess of 100 ohm[sup [minus]1] cm[sup [minus]1]. Other alloy and oxide system cermets having high content metal phases are also expected to be manufacturable in accordance with the invention.

  19. Cermet anode compositions with high content alloy phase

    DOE Patents [OSTI]

    Marschman, Steven C. (Richland, WA); Davis, Norman C. (Richland, WA)

    1989-01-01

    Cermet electrode compositions comprising NiO-NiFe.sub.2 O.sub.4 -Cu-Ni, and methods for making, are disclosed. Addition of nickel metal prior to formation and densification of a base mixture into the cermet allows for an increase in the total amount of copper and nickel that can be contained in the NiO-NiFe.sub.2 O.sub.4 oxide system. Nickel is present in a base mixture weight concentration of from 0.1% to 10%. Copper is present in the alloy phase in a weight concentration of from 10% to 30% of the densified composition. Such cermet electrodes can be formed to have electrical conductivities well in excess of 100 ohm.sup.-1 cm.sup.-1. Other alloy and oxide system cermets having high content metal phases are also expected to be manufacturable in accordance with the invention.

  20. 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

    2002-11-24

    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

  1. Highly Dispersed Alloy Catalyst for Durability

    SciTech Connect (OSTI)

    Vivek S. Murthi , Elise Izzo, Wu Bi, Sandra Guerrero and Lesia Protsailo

    2013-01-08

    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.

  2. High-temperature Hydrogen Permeation in Nickel Alloys

    SciTech Connect (OSTI)

    P. Calderoni; M. Ebner; R. Pawelko

    2010-10-01

    In gas cooled Very High Temperature Reactor concepts, tritium is produced as a tertiary fission product and by activation of graphite core contaminants, such as lithium; of the helium isotope, He-3, that is naturally present in the He gas coolant; and the boron in the B4C burnable poison. Because of its high mobility at the reactor outlet temperatures, tritium poses a risk of permeating through the walls of the intermediate heat exchanger (IHX) or steam generator (SG) systems, potentially contaminating the environment and in particular the hydrogen product when the reactor heat is utilized in connection with a hydrogen generation plant. An experiment to measure tritium permeation in structural materials at temperatures up to 1000 C has been constructed at the Idaho National Laboratory Safety and Tritium Applied Research (STAR) facility within the Next Generation Nuclear Plant program. The design is based on two counter flowing helium loops to represent heat exchanger conditions and was optimized to allow control of the materials surface condition and the investigation of the effects of thermal fatigue. In the ongoing campaign three nickel alloys are being considered because of their high-temperature creep properties, alloy 617, 800H and 230. This paper introduces the general issues related to tritium in the on-going assessment of gas cooled VHTR systems fission product transport and outlines the planned research activities in this area; outlines the features and capabilities of the experimental facility being operated at INL; presents and discusses the initial results of hydrogen permeability measurements in two of the selected alloys and compares them with the available database from previous studies.

  3. Highly Mismatched Alloys for Intermediate Band Solar Cells

    SciTech Connect (OSTI)

    Walukiewicz, W.; Yu, K.M.; Wu, J.; Ager III, J.W.; Shan, W.; Scrapulla, M.A.; Dubon, O.D.; Becla, P.

    2005-03-21

    It has long been recognized that the introduction of a narrow band of states in a semiconductor band gap could be used to achieve improved power conversion efficiency in semiconductor-based solar cells. The intermediate band would serve as a ''stepping stone'' for photons of different energy to excite electrons from the valence to the conduction band. An important advantage of this design is that it requires formation of only a single p-n junction, which is a crucial simplification in comparison to multijunction solar cells. A detailed balance analysis predicts a limiting efficiency of more than 50% for an optimized, single intermediate band solar cell. This is higher than the efficiency of an optimized two junction solar cell. Using ion beam implantation and pulsed laser melting we have synthesized Zn{sub 1-y}Mn{sub y}O{sub x}Te{sub 1-x} alloys with x<0.03. These highly mismatched alloys have a unique electronic structure with a narrow oxygen-derived intermediate band. The width and the location of the band is described by the Band Anticrossing model and can be varied by controlling the oxygen content. This provides a unique opportunity to optimize the absorption of solar photons for best solar cell performance. We have carried out systematic studies of the effects of the intermediate band on the optical and electrical properties of Zn{sub 1-y}Mn{sub y}O{sub x}Te{sub 1-x} alloys. We observe an extension of the photovoltaic response towards lower photon energies, which is a clear indication of optical transitions from the valence to the intermediate band.

  4. Technical Reference on Hydrogen Compatibility of Materials High-Alloy Ferritic Steels

    E-Print Network [OSTI]

    Siefert, Chris

    Technical Reference on Hydrogen Compatibility of Materials High-Alloy Ferritic Steels: Martensitic on Hydrogen Compatibility of Materials High-Alloy Ferritic Steels: Martensitic Stainless Steels Heat Treatable (Fe-Cr type) (code 1820) 1. General The martensitic stainless steels with low nickel are hardenable

  5. High strength and density tungsten-uranium alloys

    DOE Patents [OSTI]

    Sheinberg, Haskell (Los Alamos, NM)

    1993-01-01

    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.

  6. Ir-based alloys for ultra-high temperature applications

    DOE Patents [OSTI]

    Liu, Chain T.; George, Easo P.; Bloom, Everett E.

    2006-01-03

    An alloy composition includes, in atomic percent: about 1 to about 10% of at least one element selected from the group consisting of Zr and Hf, balance Ir.

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

    DOE Patents [OSTI]

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

    1987-04-28

    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.

  8. The Entropy of the Universe and the Maximum Entropy Production

    E-Print Network [OSTI]

    Lineweaver, Charles H.

    Chapter 22 The Entropy of the Universe and the Maximum Entropy Production Principle Charles H. Lineweaver Abstract If the universe had been born in a high entropy, equilibrium state, there would be no stars, no planets and no life. Thus, the initial low entropy of the universe is the fundamental reason

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

    SciTech Connect (OSTI)

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

    2013-03-01

    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.

  10. 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)

    2014-03-24

    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.

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

    DOE Patents [OSTI]

    Liu, C.T.; Takeyama, Masao.

    1994-02-01

    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.

  12. 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)

    1994-01-01

    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.

  13. Nickel aluminide alloy for high temperature structural use

    DOE Patents [OSTI]

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

    1991-01-01

    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.

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

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12

    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...

  15. CoNiGa High Temperature Shape Memory Alloys 

    E-Print Network [OSTI]

    Dogan, Ebubekir

    2011-10-21

    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 ...

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

    E-Print Network [OSTI]

    Needham, William Donald

    1986-01-01

    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 ...

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

    DOE Patents [OSTI]

    Hsu, Huey S.

    1988-04-14

    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.

  18. High-throughput screening of perovskite alloys for piezoelectric performance and thermodynamic stability

    E-Print Network [OSTI]

    Armiento, Rickard R.

    We screen a large chemical space of perovskite alloys for systems with optimal properties to accommodate a morphotropic phase boundary (MPB) in their composition-temperature phase diagram, a crucial feature for high ...

  19. 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...

  20. Computational Thermodynamics of CoNiGa High Temperature Shape Memory Alloys 

    E-Print Network [OSTI]

    Chari, Arpita

    2012-10-19

    Shape Memory Alloys (SMAs) are advanced materials with interesting properties such as pseudoelasticity (PE) and the shape memory effect (SME). Recently, the CoNiGa system has emerged as the basis for very promising High ...

  1. Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors 

    E-Print Network [OSTI]

    Williams, John Charles

    1991-01-01

    FORMATION OF THIN FILM Tl-BASED HIGH-Tc SUPERCONDUCTING OXIDES FROM AMORPHOUS ALLOY PRECURSORS A Thesis JOHN CHARLES WILLIAMS Submitted to the Once of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1991 Major Subject: Physics FORMATION OF THIN FILM Tl BASED HIGH Tc SUPERCONDUCTING OXIDES FROM AMORPHOUS ALLOY PRECURSORS A Thesis JOHN CHARLES WILLIAMS Approved as to style and content by: Donald G. Naugle...

  2. Candidate alloys for cost-effective, high-efficiency, high-temperature compact/foil heat-exchangers

    SciTech Connect (OSTI)

    Evans, Neal D; Maziasz, Philip J; Shingledecker, John P; Pint, Bruce A; Yamamoto, Yukinori

    2007-01-01

    Solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) systems operate at high temperatures (up to 1000 C and 650 C, respectively), which makes them especially attractive sources for combined heat and power (CHP) cogeneration. However, improvements in the efficiency of heat exchange in these fuel cells require both development and careful processing of advanced cost-effective alloys for use in such high-temperature service conditions. The high-temperature properties of both sheet and foil forms of several alloys being considered for use in compact heat-exchangers (recuperators) have been characterized. Mechanical and creep-rupture testing, oxidation studies, and microstructural studies have been performed on commercially available sheet and foil forms of alloy 347, alloys 625, HR230, HR120, and the new AL20-25+Nb. These studies have led to a mechanistic understanding of the responses of these alloys to anticipated service conditions, and suggest that these alloys developed for gas- and micro-turbine recuperator applications are also suitable for use in fuel cell heat-exchangers. Additional work is still required to achieve foil forms with creep life comparable to thicker-section wrought product forms of the same alloys.

  3. Mechanisms Governing the Creep Behavior of High Temperature Alloys for Generation IV Nuclear Energy Systems

    SciTech Connect (OSTI)

    Vasudevan, Vijay; Carroll, Laura; Sham, Sam

    2015-04-06

    This research project, which includes collaborators from INL and ORNL, focuses on the study of alloy 617 and alloy 800H that are candidates for applications as intermediate heat exchangers in GEN IV nuclear reactors, with an emphasis on the effects of grain size, grain boundaries and second phases on the creep properties; the mechanisms of dislocation creep, diffusional creep and cavitation; the onset of tertiary creep; and theoretical modeling for long-term predictions of materials behavior and for high temperature alloy design.

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

    DOE Patents [OSTI]

    Flinn, J.E.

    1998-11-03

    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.

  5. 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)

    1993-01-01

    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%.

  6. 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)

    1999-01-01

    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.

  7. 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

    2006-10-31

    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.

  8. 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)

    1999-01-01

    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.

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

    DOE Patents [OSTI]

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

    1999-02-09

    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.

  10. Super-High Temperature Alloys and Composites from NbW-Cr Systems

    SciTech Connect (OSTI)

    Shailendra Varma

    2008-12-31

    Nickel base superalloys must be replaced if the demand for the materials continues to rise for applications beyond 1000{sup o}C which is the upper limit for such alloys at this time. There are non-metallic materials available for such high temperature applications but they all present processing difficulties because of the lack of ductility. Metallic systems can present a chance to find materials with adequate room temperature ductility. Obviously the system must contain elements with high melting points. Nb has been chosen by many investigators which has a potential of being considered as a candidate if alloyed properly. This research is exploring the Nb-W-Cr system for the possible choice of alloys to be used as a high temperature material.

  11. 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

    2011-01-01

    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.

  12. High permeance sulfur tolerant Pd/Cu alloy membranes

    DOE Patents [OSTI]

    Ma, Yi Hua; Pomerantz, Natalie

    2014-02-18

    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.

  13. Design and identification of high performance steel alloys for structures subjected to underwater impulsive loading

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    Necking Dynamic fracture a b s t r a c t Martensitic and austenitic steel alloys were designed to optimize under various loading paths. The model was calibrated for two high performance martensitic steels (HSLA-100 and BA-160) and an austenitic steel (TRIP-120). The martensitic steel (BA-160) was designed

  14. 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

  15. 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

    2003-05-01

    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.

  16. High Strain-Rate Characterization of Magnesium Alloys | Department of

    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 Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancing ProgramsDepartment of¡High HIGH PERFORMANCEEnergy

  17. 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

    2013-09-01

    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.

  18. High-Temperature Aluminum Alloys | 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 Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancingR Walls - Building America Top Innovation High-R

  19. Highly Dispersed Alloy Cathode Catalyst for Durability | Department of

    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 Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancingR Walls - Building America Topa HighHigher|

  20. Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum

    SciTech Connect (OSTI)

    A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla

    2005-10-31

    Conventional processing methods for highly alloyed aluminum consist of ingot casting, followed by hot rolling and thermal treatments. Defects result in lost productivity and wasted energy through the need to remelt and reprocess the material. This research centers on developing a fundamental understanding for deformation of wrought 705X series alloys, a key alloy system used in structural airframe applications. The development of damage at grain boundaries is characterized through a novel test that provides initiation of failure while preserving a controlled deformation response. Data from these mechanical tests are linked to computer simulations of the hot rolling process through a critical measure of damage. Transmission electron microscopy provides fundamental insight into deformation at these high working temperatures, and--in a novel link between microscale and macroscale response--the evolution of microstructure (crystallographic orientation) provides feedback for tuning of friction in the hot rolling process. The key product of this research is a modeling framework for the analysis of industrial hot rolling.

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

    SciTech Connect (OSTI)

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

    1999-07-01

    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.

  2. 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 Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancing ProgramsDepartment of¡ ¢HelpHighJian Li,1 DOE

  3. Highly Dispersed Alloy Cathode Catalyst for Durability | Department of

    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 Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancingR Walls - Building America Topa HighHigher|Energy Part

  4. High spin polarization in CoFeMnGe equiatomic quaternary Heusler alloy

    SciTech Connect (OSTI)

    Bainsla, Lakhan; Suresh, K. G.; Nigam, A. K.; Manivel Raja, M.; Varaprasad, B. S. D. Ch. S.; Takahashi, Y. K.; Hono, K.

    2014-11-28

    We report the structure, magnetic property, and spin polarization of CoFeMnGe equiatomic quaternary Heusler alloy. The alloy was found to crystallize in the cubic Heusler structure (prototype LiMgPdSn) with considerable amount of DO{sub 3} disorder. Thermal analysis result indicated the Curie temperature is about 750?K without any other phase transformation up to melting temperature. The magnetization value was close to that predicted by the Slater-Pauling curve. Current spin polarization of P?=?0.70?±?0.01 was deduced using point contact andreev reflection measurements. The temperature dependence of electrical resistivity has been fitted in the temperature range of 5–300?K in order to check for the half metallic behavior. Considering the high spin polarization and Curie temperature, this material appears to be promising for spintronic applications.

  5. The high cycle fatigue and fracture behavior of aluminum alloy 7055

    SciTech Connect (OSTI)

    Srivatsan, T.S.; Anand, S.; Sriram, S.; Narendra, N. [Univ. of Akron, OH (United States). Dept. of Mechanical Engineering

    1997-12-31

    In this paper, the results of a recent study on the high-cycle fatigue and fracture behavior of aluminum alloy 7055 is presented and discussed. Specimens of the alloy, in the T7751 temper, were cyclically deformed over a range of stress amplitudes at both ambient and elevated temperatures. Increase in test temperature was found to have a detrimental influence on cyclic fatigue life of the specimens machined in the transverse orientation. Temperature was found to have little influence on fatigue life of the longitudinal specimens. No major change in macroscopic fracture mode was observed with direction of testing. Cyclic fracture, on a microscopic scale, revealed features reminiscent of both ductile and brittle mechanisms. The microscopic fracture behavior was a function of test temperature. The mechanisms governing cyclic fatigue response are discussed in light of the mutually interactive influences of microstructural effects, matrix deformation characteristics and test temperature.

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

    SciTech Connect (OSTI)

    Was, Gary; Jones, J. W.

    2013-06-21

    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.

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

    E-Print Network [OSTI]

    Evirgen, Alper

    2014-08-14

    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...

  8. 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.

    2009-08-29

    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.

  9. High-Performance Computing for Alloy Development | netl.doe.gov

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (JournalvivoHigh energy neutron ComputedHigh-Performance Computing for Alloy

  10. Swelling in several commercial alloys irradiated to very high neutron fluence

    SciTech Connect (OSTI)

    Gelles, D.S.; Pintler, J.S.

    1983-01-01

    Swelling values have been obtained from a set of commercial alloys irradiated in EBR-II to a peak fluence of 2.5 x 10/sup 23/ n/cm/sup 2/ (E > 0.1 MeV) or approx. 125 dpa covering the range 400 to 650/sup 0/C. The alloys can be ranked for swelling resistance from highest to lowest as follows: the martensitic and ferritic alloys, the niobium based alloys, the precipitation strengthened iron and nickel based alloys, the molybdenum alloys and the austenitic alloys.

  11. Experimental study of crack initiation and propagation in high- and gigacycle fatigue in titanium alloys

    SciTech Connect (OSTI)

    Bannikov, Mikhail E-mail: oborin@icmm.ru Oborin, Vladimir E-mail: oborin@icmm.ru Naimark, Oleg E-mail: oborin@icmm.ru

    2014-11-14

    Fatigue (high- and gigacycle) crack initiation and its propagation in titanium alloys with coarse and fine grain structure are studied by fractography analysis of fracture surface. Fractured specimens were analyzed by interferometer microscope and SEM to improve methods of monitoring of damage accumulation during fatigue test and to verify the models for fatigue crack kinetics. Fatigue strength was estimated for high cycle fatigue regime using the Luong method [1] by “in-situ” infrared scanning of the sample surface for the step-wise loading history for different grain size metals. Fine grain alloys demonstrated higher fatigue resistance for both high cycle fatigue and gigacycle fatigue regimes. Fracture surface analysis for plane and cylindrical samples was carried out using optical and electronic microscopy method. High resolution profilometry (interferometer-profiler New View 5010) data of fracture surface roughness allowed us to estimate scale invariance (the Hurst exponent) and to establish the existence of two characteristic areas of damage localization (different values of the Hurst exponent). Area 1 with diameter ?300 ?m has the pronounced roughness and is associated with damage localization hotspot. Area 2 shows less amplitude roughness, occupies the rest fracture surface and considered as the trace of the fatigue crack path corresponding to the Paris kinetics.

  12. High efficiency multijunction amorphous silicon alloy-based solar cells and modules

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.; Banerjeee, A.; Glatfelter, T.; Hoffman, K.; Xu, X. )

    1994-06-30

    We have achieved initial efficiency of 11.4% as confirmed by National Renewable Energy Laboratory (NREL) on a multijunction amorphous silicon alloy photovoltaic module of one-square-foot-area. [bold This] [bold is] [bold the] [bold highest] [bold initial] [bold efficiency] [bold confirmed] [bold by] [bold NREL] [bold for] [bold any] [bold thin] [bold film] [bold photovoltaic] [bold module]. After light soaking for 1000 hours at 50 [degree]C under one-sun illumination, a module with initial efficiency of 11.1% shows a stabilized efficiency of 9.5%. Key factors that led to this high performance are discussed.

  13. High-cycle fatigue behavior of Ti-5Al-2.5Sn ELI alloy forging at low temperatures

    SciTech Connect (OSTI)

    Ono, Yoshinori; Yuri, Tetsumi; Ogata, Toshio; Demura, Masahiko; Matsuoka, Saburo; Sunakawa, Hideo

    2014-01-27

    High-cycle fatigue properties of Ti-5Al-2.5Sn Extra Low Interstitial (ELI) alloy forging were investigated at low temperatures. The high-cycle fatigue strength at low temperatures of this alloy was relatively low compared with that at ambient temperature. The crystallographic orientation of a facet formed at a fatigue crack initiation site was determined by electron backscatter diffraction (EBSD) method in scanning electron microscope (SEM) to understand the fatigue crack initiation mechanism and discuss on the low fatigue strength at low temperature. Furthermore, in terms of the practical use of this alloy, the effect of the stress ratio (or mean stress) on the high-cycle fatigue properties was evaluated using the modified Goodman diagram.

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

    E-Print Network [OSTI]

    Hays, Charles C.

    1986-01-01

    THE STRUCTURAL AND MECHANICAL PROPERTIES OF A Cu6OZr4D(at. X) ALLOY PROCESSED BY HIGH-VELOCITY- INJECTION (HVI) A Thesis by CHARLES C. HAYS Submitted to the Graduate College of Texas AIIM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1986 Major Subject: Physics THE STRUCTURAL AND MECHANICAL PROPERTIES OF A CuBOZr4O(at. %) ALLOY PROCESSED BY HIGH-VELOCITY- INJECTION (HVI ) A Thesis by CHARLES C. HAYS Approved as to style and content by: D. G...

  15. A general method for multimetallic platinum alloy nanowires as highly active and stable oxygen reduction catalysts

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

    Bu, Lingzheng; Ding, Jiabao; Yao, Jianlin; Huang, Xiaoqing; Guo, Shaojun; Zhang, Xu; Lu, Gang; Su, Dong; Zhu, Xing; Guo, Jun

    2015-10-13

    The production of inorganic nanoparticles (NPs) with precise control over structures has always been a central target in various fields of chemistry and physics because the properties of NPs can be desirably manipulated by their structure.[1-4] There has been an intense search for high-performance noble metal NP catalysts particular for Pt.[5-9] Precious platinum (Pt) NPs are active catalysts for various heterogeneous reactions and show particularly superior performance in both the anodic oxidation reaction and the cathodic ORR in the fuel cells, but their rare content and high cost largely impede the practical application.[10-12] A potential strategy to address this tremendousmore »challenge is alloying Pt NPs with the transition metals (TM).[13-16]« less

  16. Fine-Scale Precipitation in the High-Entropy Alloy Al0.5CrFeCoNiCu

    E-Print Network [OSTI]

    Pickering, E. J.; Stone, H. J.; Jones, N. G.

    2015-01-01

    material after rapid cooling, demonstrating that the precipitation kinetics were not slow, as is often claimed for HEAs. Acknowledgements295 The authors acknowledge funding from Rolls-Royce plc and the EPSRC un- der the Rolls-Royce/EPSRC Strategic...

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

    E-Print Network [OSTI]

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

    2014-07-27

    evidence of shrinkage porosity. Bulk compositional assess- ment showed that each of the constituent elements were within 1 at% of the nominal composition. The distribution of each element in the as-cast state is shown in Fig. 2. Cr, Fe and Co were observed... ,2]. Traditional metallurgical wisdom would expect the microstructure of these materials to contain a number of intermetallic phases, yet surprisingly, this has not been the case. Experimental studies have reported single or dual phase as-cast microstructures [2...

  18. Amorphous and nanocrystalline phase formation in highly-driven Al-based binary alloys

    SciTech Connect (OSTI)

    Kalay, Yunus Eren

    2008-10-15

    Remarkable advances have been made since rapid solidification was first introduced to the field of materials science and technology. New types of materials such as amorphous alloys and nanostructure materials have been developed as a result of rapid solidification techniques. While these advances are, in many respects, ground breaking, much remains to be discerned concerning the fundamental relationships that exist between a liquid and a rapidly solidified solid. The scope of the current dissertation involves an extensive set of experimental, analytical, and computational studies designed to increase the overall understanding of morphological selection, phase competition, and structural hierarchy that occurs under far-from equilibrium conditions. High pressure gas atomization and Cu-block melt-spinning are the two different rapid solidification techniques applied in this study. The research is mainly focused on Al-Si and Al-Sm alloy systems. Silicon and samarium produce different, yet favorable, systems for exploration when alloyed with aluminum under far-from equilibrium conditions. One of the main differences comes from the positions of their respective T{sub 0} curves, which makes Al-Si a good candidate for solubility extension while the plunging T{sub 0} line in Al-Sm promotes glass formation. The rapidly solidified gas-atomized Al-Si powders within a composition range of 15 to 50 wt% Si are examined using scanning and transmission electron microscopy. The non-equilibrium partitioning and morphological selection observed by examining powders at different size classes are described via a microstructure map. The interface velocities and the amount of undercooling present in the powders are estimated from measured eutectic spacings based on Jackson-Hunt (JH) and Trivedi-Magnin-Kurz (TMK) models, which permit a direct comparison of theoretical predictions. For an average particle size of 10 {micro}m with a Peclet number of {approx}0.2, JH and TMK deviate from each other. This deviation indicates an adiabatic type solidification path where heat of fusion is reabsorbed. It is interesting that this particle size range is also consistent with the appearance of a microcellular growth. While no glass formation is observed within this system, the smallest size powders appear to consist of a mixture of nanocrystalline Si and Al. Al-Sm alloys have been investigated within a composition range of 34 to 42 wt% Sm. Gas atomized powders of Al-Sm are investigated to explore the morphological and structural hierarchy that correlates with different degrees of departure from full equilibrium conditions. The resultant powders show a variety of structural selection with respect to amount of undercooling, with an amorphous structure appearing at the highest cooling rates. Because of the chaotic nature of gas atomization, Cu-block melt-spinning is used to produce a homogeneous amorphous structure. The as-quenched structure within Al-34 to 42 wt% Sm consists of nanocrystalline fcc-Al (on the order of 5 nm) embedded in an amorphous matrix. The nucleation density of fcc-Al after initial crystallization is on the order of 10{sup 22}-10{sup 23} m{sup -3}, which is 10{sup 5}-10{sup 6} orders of magnitude higher than what classical nucleation theory predicts. Detailed analysis of liquid and as-quenched structures using high energy synchrotron X-ray diffraction, high energy transmission electron microscopy, and atom probe tomography techniques revealed an Al-Sm network similar in appearance to a medium range order (MRO) structure. A model whereby these MRO clusters promote the observed high nucleation density of fcc-Al nanocrystals is proposed. The devitrification path was identified using high temperature, in-situ, high energy synchrotron X-ray diffraction techniques and the crystallization kinetics were described using an analytical Johnson-Mehl-Avrami (JMA) approach.

  19. Cluster formula of Fe-containing Monel alloys with high corrosion-resistance

    SciTech Connect (OSTI)

    Li Baozeng; Gu Junjie [Key Lab of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang Qing, E-mail: wangq@dlut.edu.cn [Key Lab of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Ji Chunjun [College of Energy Source and Power, Dalian University of Science and Technology, Dalian, 116024 (China); Wang Yingmin; Qiang Jianbing [Key Lab of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Dong Chuang, E-mail: dong@dlut.edu.cn [Key Lab of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2012-06-15

    The cluster-plus-glue-atom model is applied in the composition interpretation of Monel alloys. This model considers ideal atomic nearest neighbor configurations among the constituent elements and has been used in understanding compositions of complex alloys like quasicrystals, amorphous alloys, and cupronickels. According to this model, any structure can be expressed by cluster formula [cluster](glue atom){sub x}, x denoting the number of glue atoms matching one cluster. According to this model, two groups of experimental composition series [Fe{sub 1}Ni{sub 12}]Cu{sub x} and [Fe{sub y}Ni{sub 12}]Cu{sub 5} were designed which fell close to conventional Fe-containing Monel alloys. The designed alloys after solution treatment plus water quenching, are monolithic FCC Ni-based solid solutions. Among them, the [Fe{sub 1}Ni{sub 12}]Cu{sub 5} alloy has the highest corrosion resistance in simulated sea water, and its performance is superior to that of industrial Monel 400 alloy. - Highlights: Black-Right-Pointing-Pointer A stable solid solution model is proposed using our 'cluster-plus-glue-atom model'. Black-Right-Pointing-Pointer This model is used to develop Monel corrosion resistant alloys. Black-Right-Pointing-Pointer Single FCC structure is easily retained. Black-Right-Pointing-Pointer The alloys show good corrosion properties. Black-Right-Pointing-Pointer This work contributes to the general understanding of engineering alloys.

  20. 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

    2013-06-15

    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.

  1. Improved performance rhenium containing single crystal alloy turbine blades utilizing ppm levels of the highly reactive elements lanthanum and yttrium

    SciTech Connect (OSTI)

    Ford, D.A.; Fullagar, K.P.L.; Bhangu, H.K. [Rolls-Royce PLC, Bristol (United Kingdom); Thomas, M.C.; Burkholder, P.S.; Korinko, P.S. [Allison Engine Co., Indianapolis, IN (United States); Harris, K.; Wahl, J.B. [Cannon-Muskegon Corp., MI (United States)

    1999-01-01

    Turbine inlet temperatures have now approached 1650 C at maximum power for the latest large commercial turbofan engines, resulting in high fuel efficiency and thrust levels approaching or exceeding 445 kN (100,000 lbs.). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. Re additions to cast airfoil superalloys not only improve creep and thermomechanical fatigue strength but also environmental properties, including coating performance. It is now known that sulfur (S) at levels <10 ppm but >0.2 ppm in these alloys reduces the adherence of {alpha} alumina protective scales on these materials or their coatings by weakening the Van der Waal`s bond between the scale and the alloy substrate. A team approach has been used to develop an improvement to CMSX-4 alloy which contains 3% Re, by reducing S and phosphorus (P) levels in the alloy to <2 ppm, combined with residual additions of lanthanum (La) + yttrium (Y) in the range 10--30 ppm. Results from cyclic, burner rig dynamic oxidation testing at 1093 C show thirteen times the number of cycles to initial alumina scale spallation for CMSX-4 [La + Y] compared to standard CMSX-4. The La assists with ppm chemistry control of the Y throughout the single crystal turbine blade castings through the formation of a continuous lanthanum oxide film between the molten and solidifying alloy and the ceramic core and prime coat of the shell mold. Y and La tie up the M2 ppm but >0.2 ppm residual S in the alloy as very stable Y and La sulfides and oxysulfides, thus preventing diffusion of the S atoms to the alumina scale layer under high temperature, cyclic oxidizing conditions. La also forms a stable phosphide. CMSX-4 (ULS) (La + Y) HP shroudless turbine blades will commence engine testing in May 1998.

  2. Pt monolayer shell on nitrided alloy core — A path to highly stable oxygen reduction catalyst

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

    Hu, Jue; Kuttiyiel, Kurian A.; Sasaki, Kotaro; Su, Dong; Yang, Tae -Hyun; Park, Gu -Gon; Zhang, Chengxu; Chen, Guangyu; Adzic, Radoslav R.

    2015-07-22

    The inadequate activity and stability of Pt as a cathode catalyst under the severe operation conditions are the critical problems facing the application of the proton exchange membrane fuel cell (PEMFC). Here we report on a novel route to synthesize highly active and stable oxygen reduction catalysts by depositing Pt monolayer on a nitrided alloy core. The prepared PtMLPdNiN/C catalyst retains 89% of the initial electrochemical surface area after 50,000 cycles between potentials 0.6 and 1.0 V. By correlating electron energy-loss spectroscopy and X-ray absorption spectroscopy analyses with electrochemical measurements, we found that the significant improvement of stability of themore »PtMLPdNiN/C catalyst is caused by nitrogen doping while reducing the total precious metal loading.« less

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

    DOE Patents [OSTI]

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

    1993-08-24

    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%.

  4. Modelling the coarsening behaviour of TiC precipitates in high-strength, low-alloy steels

    E-Print Network [OSTI]

    Cambridge, University of

    Modelling the coarsening behaviour of TiC precipitates in high-strength, low-alloy steels Jae Hoon­sheet steels rely on a dispersion of fine precipitates based on TiC, generated during the major phase changes of the stoichiometry of titanium and carbon. The purpose was to assess the influences of interface energy and Ti/C

  5. 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...

  6. Highly-enhanced reflow characteristics of sputter deposited Cu alloy thin films for large scale integrated interconnections

    SciTech Connect (OSTI)

    Onishi, Takashi; Mizuno, Masao; Yoshikawa, Tetsuya; Munemasa, Jun; Mizuno, Masataka; Kihara, Teruo; Araki, Hideki; Shirai, Yasuharu

    2011-08-01

    An attempt to improve the reflow characteristics of sputtered Cu films was made by alloying the Cu with various elements. We selected Y, Sb, Nd, Sm, Gd, Dy, In, Sn, Mg, and P for the alloys, and ''the elasto-plastic deformation behavior at high temperature'' and ''the filling level of Cu into via holes'' were estimated for Cu films containing each of these elements. From the results, it was found that adding a small amount of Sb or Dy to the sputtered Cu was remarkably effective in improve the reflow characteristics. The microstructure and imperfections in the Cu films before and after high-temperature high-pressure annealing were investigated by secondary ion micrographs and positron annihilation spectroscopy. The results imply that the embedding or deformation mechanism is different for the Cu-Sb alloy films compared to the Cu-Dy alloy films. We consider that the former is embedded by softening or deformation of the Cu matrix, which has a polycrystalline structure, and the latter is embedded by grain boundary sliding.

  7. Rules for design of Alloy 617 nuclear components to very high temperatures

    SciTech Connect (OSTI)

    Corum, J.M.; Blass, J.J.

    1991-01-01

    Very-high-temperature gas-cooled reactors provide attractive options for electric power generation using a direct gas-turbine cycle and for process-heat applications. For the latter, temperatures of at least 950{degree}C (1742{degree}F) are desirable. As a first step to providing rules for the design of nuclear components operating at very high temperatures, a draft ASME Boiler and Pressure Vessel Code Case has been prepared by an ad hoc Code task force. The Case, which is patterned after the high-temperature nuclear Code Case N-47, covers Ni-Cr-Co-Mo Alloy 617 for temperatures to 982{degree}C (1800{degree}F). The purpose of this paper is to provide a synopsis of the draft Case and the significant differences between it and Case N-47. Particular emphasis is placed on the material behavior and allowables. The paper also recommends some materials and structures development activities that are needed to place the design methodology on a sound and defensible footing. 4 refs., 9 figs., 1 tab.

  8. 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)

    1996-01-01

    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.

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

    DOE Patents [OSTI]

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

    1996-08-13

    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.

  10. High Efficiency Triple-Junction Amorphous Silicon Alloy Photovoltaic Technology, Final Technical Report, 6 March 1998 - 15 October 2001

    SciTech Connect (OSTI)

    Guha, S.

    2001-11-08

    This report describes the research program intended to expand, enhance, and accelerate knowledge and capabilities for developing high-performance, two-terminal multijunction amorphous silicon (a-Si) alloy cells, and modules with low manufacturing cost and high reliability. United Solar uses a spectrum-splitting, triple-junction cell structure. The top cell uses an amorphous silicon alloy of {approx}1.8-eV bandgap to absorb blue photons. The middle cell uses an amorphous silicon germanium alloy ({approx}20% germanium) of {approx}1.6-eV bandgap to capture green photons. The bottom cell has {approx}40% germanium to reduce the bandgap to {approx}1.4-eV to capture red photons. The cells are deposited on a stainless-steel substrate with a predeposited silver/zinc oxide back reflector to facilitate light-trapping. A thin layer of antireflection coating is applied to the top of the cell to reduce reflection loss. The major research activities conducted under this program were: (1) Fundamental studies to improve our understanding of materials and devices; the work included developing and analyzing a-Si alloy and a-SiGe alloy materials prepared near the threshold of amorphous-to-microcrystalline transition and studying solar cells fabricated using these materials. (2) Deposition of small-area cells using a radio-frequency technique to obtain higher deposition rates. (3) Deposition of small-area cells using a modified very high frequency technique to obtain higher deposition rates. (4) Large-area cell research to obtain the highest module efficiency. (5) Optimization of solar cells and modules fabricated using production parameters in a large-area reactor.

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

    SciTech Connect (OSTI)

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

    2014-04-01

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

  12. 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.

    2009-10-06

    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

  13. Research on high-efficiency, multiple-gap, multijunction, amorphous-silicon-based alloy thin-film solar cells

    SciTech Connect (OSTI)

    Guha, S. )

    1989-06-01

    This report presents results of research on advancing our understanding of amorphous-silicon-based alloys and their use in small-area multijunction solar cells. The principal objectives of the program are to develop a broad scientific base for the chemical, structural, optical, and electronic properties of amorphous-silicon-based alloys; to determine the optimum properties of these alloy materials as they relate to high-efficiency cells; to determine the optimum device configuration for multijunction cells; and to demonstrate proof-of-concept, multijunction, a-Si-alloy-based solar cells with 18% efficiency under standard AM1.5 global insolation conditions and with an area of at least 1 cm{sup 2}. A major focus of the work done during this reporting period was the optimization of a novel, multiple-graded structure that enhances cell efficiency through band-gap profiling. The principles of the operation of devices incorporating such a structure, computer simulations of those, and experimental results for both single- and multijunction cells prepared by using the novel structure are discussed in detail. 14 refs., 35 figs., 7 tabs.

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

    E-Print Network [OSTI]

    Benz, Julian K

    2009-01-01

    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 ...

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

    DOE Patents [OSTI]

    Hobson, David O. (Oak Ridge, TN)

    1998-01-01

    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.

  16. Microstructure–property relationships in a high-strength 51Ni–29Ti–20Hf shape memory alloy

    SciTech Connect (OSTI)

    Coughlin, D. R.; Casalena, L.; Yang, F.; Noebe, R. D.; Mills, M. J.

    2015-09-18

    NiTiHf alloys exhibit remarkable shape memory and pseudoelastic properties that are of fundamental interest to a growing number of industries. In this study, differential scanning calorimetry and isothermal compression tests have revealed that the 51Ni–29Ti–20Hf alloy has useful shape memory properties that include a wide range of transformation temperatures as well as highly stable pseudoelastic behavior. These properties are governed by short-term aging conditions, which may be tailored to control transformation temperatures while giving rise to exceptionally high austenite yield strengths which aid transformation stability. The yield strength of the austenite phase can reach 2.1 GPa by aging for 3hrs at 500°C, while aging for 3hrs at 700°C produced an alloy with an austenite finish temperature (A f ) of 146°C. High-resolution scanning transmission electron microscopy has revealed a new precipitate phase, H-phase, under the homogenized and extruded condition and the aged 3 hrs at 500°C condition, but only the previously identified H-phase precipitate was observed after aging at temperatures of 600°C and 700°C for 3 hrs. Finally, dislocation analysis indicated that plastic deformation of the austenite phase occurred by <100> type slip, similar to that observed in binary NiTi.

  17. Microstructure–property relationships in a high-strength 51Ni–29Ti–20Hf shape memory alloy

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

    Coughlin, D. R.; Casalena, L.; Yang, F.; Noebe, R. D.; Mills, M. J.

    2015-09-18

    NiTiHf alloys exhibit remarkable shape memory and pseudoelastic properties that are of fundamental interest to a growing number of industries. In this study, differential scanning calorimetry and isothermal compression tests have revealed that the 51Ni–29Ti–20Hf alloy has useful shape memory properties that include a wide range of transformation temperatures as well as highly stable pseudoelastic behavior. These properties are governed by short-term aging conditions, which may be tailored to control transformation temperatures while giving rise to exceptionally high austenite yield strengths which aid transformation stability. The yield strength of the austenite phase can reach 2.1 GPa by aging for 3hrsmore »at 500°C, while aging for 3hrs at 700°C produced an alloy with an austenite finish temperature (A f ) of 146°C. High-resolution scanning transmission electron microscopy has revealed a new precipitate phase, H-phase, under the homogenized and extruded condition and the aged 3 hrs at 500°C condition, but only the previously identified H-phase precipitate was observed after aging at temperatures of 600°C and 700°C for 3 hrs. Finally, dislocation analysis indicated that plastic deformation of the austenite phase occurred by type slip, similar to that observed in binary NiTi.« less

  18. Achievement of high coercivity in sintered R-Fe-B magnets based on misch-metal by dual alloy method

    SciTech Connect (OSTI)

    Niu, E Wang, Zhen-Xi; Chen, Zhi-An; Rao, Xiao-Lei; Hu, Bo-Ping; Chen, Guo-An; Zhao, Yu-Gang; Zhang, Jin

    2014-03-21

    The R-Fe-B (R, rare earth) sintered magnets prepared with different ratio of alloys of MM-Fe-B (MM, misch-metal) and Nd-Fe-B by dual alloy method were investigated. As expected, the high ratio of MM-Fe-B alloy degrades the hard magnetic properties heavily with intrinsic coercivity lower than 5 kOe. When the atomic ratio MM/R???21.5% the magnetic properties can reach a practical level of B{sub r}???12.1 kGs, H{sub cj}???10.7 kOe, and (BH){sub max}???34.0 MGOe. And the effect of H{sub cj} enhancement by the grain boundary diffusion process is obvious when MM/R???21.5%. It is revealed that the decrement of intrinsic magnetic properties of R{sub 2}Fe{sub 14}B matrix phase is not the main reason of the degradation of the magnets with high MM ratio. The change of deteriorated microstructure together with phase component plays fundamental roles in low H{sub cj}. In high MM ratio magnets, (a) after annealing, Ce atoms inside main phase are inclined to be segregated in the outer layer of the main phase grains; (b) there is no thin layer of Ce-rich phase as an analogue of Nd-rich phase to separate main phase grains; (c) excessive Ce tends to form CeFe{sub 2} grains.

  19. 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

    2012-12-01

    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.

  20. 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)

    2011-11-29

    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.

  1. Ductile transplutonium metal alloys

    DOE Patents [OSTI]

    Conner, William V. (Boulder, CO)

    1983-01-01

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources 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.

  2. Ductile transplutonium metal alloys

    DOE Patents [OSTI]

    Conner, W.V.

    1981-10-09

    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.

  3. Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

    SciTech Connect (OSTI)

    Li, P., E-mail: pli@sqnc.edu.cn [Department of Physics and Information Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Lei, M.K., E-mail: surfeng@dlut.edu.cn [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Zhu, X.P. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2011-06-15

    High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance. - Research Highlights: {yields} A modified layer about 30 {mu}m thick is obtained by HIPIB irradiation. {yields} Selective ablation of element/impurity phase having lower melting point is observed. {yields} More importantly, microstructural refinement occurred on the irradiated surface. {yields} The modified layer exhibited a significantly improved corrosion resistance. {yields} Improved corrosion resistance is ascribed to the combined effect induced by HIPIB.

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

    DOE Patents [OSTI]

    Hobson, D.O.

    1998-01-06

    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.

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

    SciTech Connect (OSTI)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14

    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) .

  6. 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)

    1982-01-01

    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.

  7. 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

    2014-09-30

    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.

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

    SciTech Connect (OSTI)

    K. Coulter

    2010-12-31

    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.

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

    E-Print Network [OSTI]

    Alex Kovner; Michael Lublinsky

    2015-06-17

    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.

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

    E-Print Network [OSTI]

    Kovner, Alex

    2015-01-01

    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.

  11. 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

    2012-07-03

    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.

  12. GRAMMAR SPECIALIZATION THROUGH ENTROPY THRESHOLDS

    E-Print Network [OSTI]

    in the nodes with sufficiently high entropy values. BACKGROUND Previous work by Manny Rayner and the author, see [Samuelsson &~Rayner 1991] attempts to tailor an ex- isting natural-language system to a specific. 1992] adapted to the Atis domain for a speech-translation task [Rayner el al 1993] and large corpora

  13. 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)

    2010-08-24

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

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

    SciTech Connect (OSTI)

    J. Douglas Way

    2003-01-01

    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.

  15. 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 Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de; Caldas, A.; Alho, B. P.; Carvalho, G.; Magnus, A.

    2014-10-14

    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.

  16. Characterisation of matrix entropies

    E-Print Network [OSTI]

    Frank Hansen; Zhihua Zhang

    2015-03-16

    The notion of matrix entropy was introduced by Tropp and Chen with the aim of measuring the fluctuations of random matrices. It is a certain entropy functional constructed from a representing function with prescribed properties, and Tropp and Chen gave some examples. We give several abstract characterisations of matrix entropies together with a sufficient condition in terms of the second derivative of their representing function.

  17. Earth's extensive entropy bound

    E-Print Network [OSTI]

    A. M. Lisewski

    2012-12-20

    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.

  18. Response of nanostructured ferritic alloys to high-dose heavy ion irradiation

    SciTech Connect (OSTI)

    Parish, Chad M.; White, Ryan M.; LeBeau, James M.; Miller, Michael K.

    2014-02-01

    A latest-generation aberration-corrected scanning/transmission electron microscope (STEM) is used to study heavy-ion-irradiated nanostructured ferritic alloys (NFAs). Results are presented for STEM X-ray mapping of NFA 14YWT irradiated with 10 MeV Pt to 16 or 160 dpa at -100°C and 750°C, as well as pre-irradiation reference material. Irradiation at -100°C results in ballistic destruction of the beneficial microstructural features present in the pre-irradiated reference material, such as Ti-Y-O nanoclusters (NCs) and grain boundary (GB) segregation. Irradiation at 750°C retains these beneficial features, but indicates some coarsening of the NCs, diffusion of Al to the NCs, and a reduction of the Cr-W GB segregation (or solute excess) content. Ion irradiation combined with the latest-generation STEM hardware allows for rapid screening of fusion candidate materials and improved understanding of irradiation-induced microstructural changes in NFAs.

  19. Boltzmann Entropy : Probability and Information

    E-Print Network [OSTI]

    C. G. Chakrabarti; Indranil Chakrabarty

    2007-05-20

    We have presented first an axiomatic derivation of Boltzmann entropy on the basis of two axioms consistent with two basic properties of thermodynamic entropy. We have then studied the relationship between Boltzmann entropy and information along with its physical significance.

  20. Directly correlated transmission electron microscopy and atom probe tomography of grain boundary oxidation in a Ni-Al binary alloy exposed to high-temperature water.

    SciTech Connect (OSTI)

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

    2013-10-30

    Intergranular oxidation of a Ni-4Al alloy exposed to hydrogenated, high-temperature water was characterized using directly correlated transmission electron microscopy and atom probe tomography. These combined analyses revealed that discrete, well-separated oxides (NiAl2O4) precipitated along grain boundaries in the metal. Aluminum was depleted from the grain boundary between oxides and also from one side of the boundary as a result of grain boundary migration. The discrete oxide morphology, disconnected from the continuous surface oxidation, suggests intergranular solid-state internal oxidation of Al. Keywords: oxidation; grain boundaries; nickel alloys; atom probe tomography; transmission electron microscopy (TEM)

  1. Influence of sulfate reducing bacterial biofilm on corrosion behavior of low-alloy, high-strength steel (API-5L X80)

    E-Print Network [OSTI]

    ). Microbiologically influenced corrosion (MIC) is one of the most damaging mechanisms to pipeline steel materials deposit corrosion, cracking, enhanced erosion corrosion and dealloying (Little and Lee, 2007). PipelinesInfluence of sulfate reducing bacterial biofilm on corrosion behavior of low-alloy, high

  2. The Holographic Entropy Cone

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

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phasemore »space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.« less

  3. Fractal von Neumann entropy

    E-Print Network [OSTI]

    Wellington da Cruz

    2002-10-01

    We consider the {\\it fractal von Neumann entropy} associated with the {\\it fractal distribution function} and we obtain for some {\\it universal classes h of fractons} their entropies. We obtain also for each of these classes a {\\it fractal-deformed Heisenberg algebra}. This one takes into account the braid group structure of these objects which live in two-dimensional multiply connected space.

  4. Entropy of the Universe

    E-Print Network [OSTI]

    Marcelo Samuel Berman

    2009-04-20

    After a discussion on several limiting cases where General Relativity turns into less sophisticated theories, we find that in the correct thermodynamical and cosmological weak field limit of Einstein's field equations the entropy of the Universe is R^(3/2) -- dependent, where R stands for the radius of the causally related Universe. Thus, entropy grows in the Universe, contrary to Standard Cosmology prediction.

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

    SciTech Connect (OSTI)

    Kratz, Karl-Ludwig; Farouqi, Khalil; Möller, Peter E-mail: kfarouqi@lsw.uni-heidelberg.de

    2014-09-01

    Attempts to explain the source of r-process elements in our solar system (S.S.) by particular astrophysical sites still face entwined uncertainties, stemming from the extrapolation of nuclear properties far from stability, inconsistent sources of different properties (e.g., nuclear masses and ?-decay properties), and the poor understanding of astrophysical conditions, which are hard to disentangle. In this paper we present results from the investigation of 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 ?-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 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 ? 110 and {sup 209}Bi, as well as remaining deficiencies, are discussed in terms of the underlying spherical and deformed shell structure far from stability.

  6. 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

    2014-06-10

    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.

  7. Entropy of electrolytes

    E-Print Network [OSTI]

    Laird, Brian Bostian; Haymet, A. D. J.

    1994-01-01

    The entropy of 1–1 and 2–2 model electrolytes is calculated from an expansion in terms of the multiparticle correlation functions. For electrolytes, a simple truncation of this expansion is never sufficient for the accurate calculation...

  8. 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...

  9. 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...

  10. 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...

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

    SciTech Connect (OSTI)

    J. Douglas Way

    2001-07-31

    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 H2 separation. These membranes consist of a thin ({approx}1 mm) 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 H2 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 4}0 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.

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

    E-Print Network [OSTI]

    Ozel, Tugrul

    in the cutting tool as well as residual stresses in the machine surface layer. Experimental studies are conducted using a 4-axis high-speed milling machine. Tool materials evaluated include carbides, coated carbides. Introduction As a result of the advances in machine tools and cutting tool technology, end milling at high

  13. PHYSICAL REVIEW B 84, 214110 (2011) Ordered phases in ruthenium binary alloys from high-throughput first-principles calculations

    E-Print Network [OSTI]

    Hart, Gus

    2011-01-01

    properties, as a pure element and as an alloy component. Ruthenium's practical importance as a catalytic-oxidation, CO electro-oxidation, and methane steam reforming).7 Experimental examples of this potential

  14. Micromagnetic simulation of high-power spin-torque oscillator in half-metallic Heusler alloy spin valve nanopillar

    E-Print Network [OSTI]

    Chen, Long-Qing

    valve nanopillar H. B. Huang, X. Q. Ma, Z. H. Liu, C. P. Zhao, and L. Q. Chen Citation: AIP Advances 3 in half-metallic Heusler alloy spin valve nanopillar H. B. Huang,1,2 X. Q. Ma,1,a Z. H. Liu,1 C. P. Zhao,1 investigated the spin-torque oscillator in a half-metallic Heusler alloy Co2MnSi (CMS) spin-valve nanopillar

  15. Hydrogen embrittlement, grain boundary segregation, and stress corrosion cracking of alloy X-750 in low- and high-temperature water

    SciTech Connect (OSTI)

    Mills, W. J.; Lebo, M. R.; Kearns, J. J. [Bettis Atomic Power Lab., West Mifflin, PA (United States)

    1997-04-01

    The nature of intergranular stress corrosion cracking (SCC) of alloy X-750 was characterized in low- and high-temperature water by testing as-notched and precracked fracture mechanics specimens. Materials given the AH, BH, and HTH heat treatments were studied. While all heat treatments were susceptible to rapid low-temperature crack propagation (LTCP) below 150 C, conditions AH and BH were particularly susceptible. Low-temperature tests under various loading conditions (e.g., constant displacement, constant load, and increasing load) revealed that the maximum stress intensity factors (K{sub P{sub max}}) from conventional rising load tests provide conservative estimates of the critical loading conditions in highly susceptible heats, regardless of the load path history. For resistant heats, K{sub P{sub max}} provides a reasonable, but not necessarily conservative, estimate of the critical stress intensity factor for LTCP. Testing of as-notched specimens showed that LTCP will not initiate at a smooth surface or notch, but will readily occur if a cracklike defect is present. Comparison of the cracking response in water with that for hydrogen-precharged specimens tested in air demonstrated that LTCP is associated with hydrogen embrittlement of grain boundaries. The stress corrosion crack initiation and growth does occur in high-temperature water (>250 C), but crack growth rates are orders of magnitude lower than LTCP rates. The SCC resistance of HTH heats is far superior to that of AH heats as crack initiation times are two to three orders of magnitude greater and growth rates are one to two orders of magnitude lower.

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

    E-Print Network [OSTI]

    Kumar, Parikshith K.

    2010-07-14

    and encouraged me to high standards and saw to it that I completed my requirements. He has taught me many virtues on life and research, which I hold dearly. I would also like to thank Dr. Ibrahim Karaman for the interesting and useful discussions, insight... . . . . . . . . . . . . . . . . . . . . 14 1. Fabrication and Calorimetry . . . . . . . . . . . . . . 14 2. Thermomechanical Testing . . . . . . . . . . . . . . . 15 a. Uniaxial Testing . . . . . . . . . . . . . . . . . . . 18 b. Constant Load Thermal Cycling . . . . . . . . . . 19 c...

  17. 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

    2008-11-15

    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.

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

    SciTech Connect (OSTI)

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

    2014-11-01

    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.

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

    SciTech Connect (OSTI)

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

    2012-06-07

    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.

  20. High-Alloy Ferritic Steels: Martensitic Stainless Steels, Precipitation Hardening (code 1810)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation CurrentHenry Bellamy, Ph.D. Title: Professor -|High energy

  1. High-Alloy Ferritic Steels: Semi-Austenitic Stainless Steels (code 1700)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation CurrentHenry Bellamy, Ph.D. Title: Professor -|High energySemi-Austenitic

  2. Numerical Calculation of Granular Entropy

    E-Print Network [OSTI]

    Asenjo, Daniel; Paillusson, Fabien; Frenkel, Daan

    2014-03-05

    particles are distinguishable, we have to include a factor 1/N! to ensure that the entropy does not change when exchanging particles between systems in the same macroscopic state. Our simulations provide strong evidence that the packing entropy, when...

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

    SciTech Connect (OSTI)

    Nan Mu

    2007-12-01

    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.%.

  4. Algebraic entropy for algebraic maps

    E-Print Network [OSTI]

    A. N. W. Hone; O. Ragnisco; F. Zullo

    2015-08-06

    We propose an extension of the concept of algebraic entropy, as introduced by Bellon and Viallet for rational maps, to algebraic maps (or correspondences) of a certain kind. The corresponding entropy is an index of the complexity of the map. The definition inherits the basic properties from the definition of entropy for rational maps. We give an example with positive entropy, as well as two examples taken from the theory of Backlund transformations.

  5. 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

    2008-09-30

    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.

  6. 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.

    1998-07-28

    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.

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

    SciTech Connect (OSTI)

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

    2014-10-01

    High-resolution microscopy of a high-purity Ni-5Cr alloy exposed to 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.

  8. Paper GT2004-54239 for 2004 Turbo Expo Austenitic Stainless Steels and Alloys With Improved High-Temperature

    E-Print Network [OSTI]

    Pennycook, Steve

    generation (DG), combined heat and power (CHP), and possibly combined cycle (microturbine-fuel cell recuperators/heat-exchangers increase the efficiency of both microturbines and smaller industrial gas turbines and corrosion resistance, including alloys NF709, HR120. Similar data are also provided on small lab heats

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

    SciTech Connect (OSTI)

    Yang, Shizhong

    2013-02-28

    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.

  10. Renyi Entropy and Free Energy

    E-Print Network [OSTI]

    John C. Baez

    2011-06-06

    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.

  11. 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.

    2005-10-01

    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.

  12. Liquid metal ion source and alloy

    SciTech Connect (OSTI)

    Clark, Jr., William M. (Thousand Oaks, CA); Utlaut, Mark W. (Saugus, CA); Behrens, Robert G. (Los Alamos, NM); Szklarz, Eugene G. (Los Alamos, NM); Storms, Edmund K. (Los Alamos, NM); Santandrea, Robert P. (Santa Fe, NM); Swanson, Lynwood W. (McMinnville, OR)

    1988-10-04

    A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

  13. Shannon Entropy: Axiomatic Characterization and Application

    E-Print Network [OSTI]

    C. G. Chakrabarti; Indranil Chakrabarty

    2005-11-17

    We have presented a new axiomatic derivation of Shannon Entropy for a discrete probability distribution on the basis of the postulates of additivity and concavity of the entropy function.We have then modified shannon entropy to take account of observational uncertainty.The modified entropy reduces, in the limiting case, to the form of Shannon differential entropy. As an application we have derived the expression for classical entropy of statistical mechanics from the quantized form of the entropy.

  14. 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)

    2000-12-01

    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.

  15. Entropy, Gravitation, and Thermodynamics

    E-Print Network [OSTI]

    John A. Gowan

    2009-07-02

    The relationship between the intrinsic motion of gravity, light, and time is explored in terms of the principles of entropy, causality, energy, and symmetry conservation. A conceptual mechanism for gravity and the gravitational connection between quantum mechanics and relativity is explored. A "concept equation" is given for the gravitational annihilation of space and the extraction of a metrically equivalent temporal residue. The relationship of gravity to the other forces is discussed, including the reason for the weakness of gravity.

  16. Status of Testing and Characterization of CMS Alloy 617 and Alloy 230

    SciTech Connect (OSTI)

    Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)

    2006-08-01

    Status and progress in testing and characterizing CMS Alloy 617 and Alloy 230 tasks in FY06 at ORNL and INL are described. ORNL research has focused on CMS Alloy 617 development and creep and tensile properties of both alloys. In addition to refurbishing facilities to conduct tests, a significant amount of creep and tensile data on Alloy 230, worth several years of research funds and time, has been located and collected from private enterprise. INL research has focused on the creep-fatigue behavior of standard chemistry Alloy 617 base metal and fusion weldments. Creep-fatigue tests have been performed in air, vacuum, and purified Ar environments at 800 and 1000 C. Initial characterization and high-temperature joining work has also been performed on Alloy 230 and CCA Alloy 617 in preparation for creep-fatigue testing.

  17. Alloy nanoparticle synthesis using ionizing radiation

    DOE Patents [OSTI]

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

    2011-08-16

    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.

  18. Entropy and the Predictability of Online Life

    E-Print Network [OSTI]

    Sinatra, Roberta

    2014-01-01

    Using mobile phone records and information theory measures, our daily lives have been recently shown to follow strict statistical regularities, and our movement patterns are to a large extent predictable. Here, we apply entropy and predictability measures to two data sets of the behavioral actions and the mobility of a large number of players in the virtual universe of a massive multiplayer online game. We find that movements in virtual human lives follow the same high levels of predictability as offline mobility, where future movements can to some extent be predicted well if the temporal correlations of visited places are accounted for. Time series of behavioral actions show similar high levels of predictability, even when temporal correlations are neglected. Entropy conditional on specific behavioral actions reveals that in terms of predictability negative behavior has a wider variety than positive actions. The actions which contain information to best predict an individual's subsequent action are negative,...

  19. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, C.T.

    1998-03-10

    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.

  20. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN)

    1998-01-01

    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.

  1. Experimental superplastic characterization of advanced aluminum alloys 

    E-Print Network [OSTI]

    Kopp, Christopher Carl

    1991-01-01

    categories. The first category is experimental SPF testing procedures at a constant crosshead velocity without an applied hydrostatic pressure, where SPF test data does not accurately measure the superplastic . properties of the alloy under study... recrystallization and cavitation in the alloy. This research involves the design and development of a test system to characterize the SPF properties of advanced aluminum alloys. The system in this study is constructed around an Instron testing machine, high...

  2. Tritium Production from Palladium Alloys

    SciTech Connect (OSTI)

    Claytor, T.N.; Schwab, M.J.; Thoma, D.J.; Teter, D.F.; Tuggle, D.G.

    1998-04-19

    A number of palladium alloys have been loaded with deuterium or hydrogen under low energy bombardment in a system that allows the continuous measurement of tritium. Long run times (up to 200 h) result in an integration of the tritium and this, coupled with the high intrinsic sensitivity of the system ({approximately}0.1 nCi/l), enables the significance of the tritium measurement to be many sigma (>10). We will show the difference in tritium generation rates between batches of palladium alloys (Rh, Co, Cu, Cr, Ni, Be, B, Li, Hf, Hg and Fe) of various concentrations to illustrate that tritium generation rate is dependent on alloy type as well as within a specific alloy, dependent on concentration.

  3. Clausius entropy for arbitrary bifurcate null surfaces

    E-Print Network [OSTI]

    Baccetti, Valentina

    2013-01-01

    Is entropy objectively "real"? Or is entropy in some sense subjective and observer-dependent? These innocent questions open a Pandora's box of often inconclusive debate. A consensus opinion, though certainly not universally held, seems to be that the Clausius entropy (thermodynamic entropy, defined via a Clausius relation d S = dQ/T) should be objectively real, but that the ontological status of the statistical entropy (the Shannon or von Neumann entropy) is much more ambiguous, and much more likely to be observer-dependent. This question is particularly pressing when it comes to understanding Bekenstein entropy (black hole entropy). To perhaps further add to the confusion, we shall argue that even Clausius entropy can often be observer-dependent. We shall demonstrate that one can meaningfully assign a notion of Clausius entropy to the matter crossing arbitrary bifurcate null surfaces --- effectively defining a virtual Clausius entropy" for arbitrary virtual causal horizons".

  4. Researchers create first entropy-stabilized complex oxide alloys | Argonne

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II) byMultiday Production of SOAResearchers Borrow From Fir TreeNational

  5. 3D characterization of intermetallics in a high pressure die cast Mg alloy using focused ion beam tomography

    SciTech Connect (OSTI)

    Nagasekhar, A.V. [ARC Centre of Excellence for Design in Light Metals, Materials Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Caceres, C.H., E-mail: c.caceres@uq.edu.au [ARC Centre of Excellence for Design in Light Metals, Materials Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Kong, C. [Electron Microscope Unit, UNSW Analytical Centre, University of New South Wales, Sydney, NSW 2052 (Australia)

    2010-11-15

    The degree of spatial interconnection of the Mg{sub 17}Al{sub 12} ({beta}-phase) intermetallic in a Mg-9Al-1Zn alloy was assessed through serial sectioning at the centre and near a corner in a casting cross-section. The three dimensional reconstructions showed that the intermetallics were profusely interconnected forming a scaffold-like network over the entire cross-section, but especially near the casting surface. The scale and degree of the interconnection appeared determined by the local concentration of large dendritic grains injected from the shot sleeve. The volume fractions of intermetallics obtained through the 3D reconstruction indicated a higher content of {beta}-phase at the corner regions in comparison with the core. The volume fractions obtained by FIB were consistent with theoretical and experimental values obtained using other techniques.

  6. Mechanisms of structural evolutions associated with the high current pulsed electron beam treatment of a NiTi shape memory alloy

    SciTech Connect (OSTI)

    Zhang, K. M.; Zou, J. X.; Grosdidier, T.; Gey, N.; Weber, S.; Yang, D. Z.; Dong, C. [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China) and State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024 (China); School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024 (China); and Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, UMR-CNRS 7078), Universite Paul Verlaine de Metz, Ile du Saulcy, 57012 Metz (France); Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, UMR-CNRS 7078), Universite Paul Verlaine de Metz, Ile du Saulcy, 57012 Metz (France); Laboratoire de Physique des Materiaux (LPM, UMR-CNRS 7556), Ecole des Mines, Parc de Saurupt, 54042 Nancy (France); School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China) and State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024 (China)

    2007-01-15

    The aim of this study was to investigate, for the first time, the surface modifications associated with the use the recently developed high current pulsed electron beam technique for modifying the surface of an intermetallic NiTi alloy. Samples were treated with the same electron beam parameters but different numbers of pulses (i.e., five and ten pulses) and the present article concentrates on a detailed characterization of their texture and microstructure modifications. The observation of surface features such as craters, wavy surfaces with protrusions, chemistry modifications, and the development of specific texture components are discussed as the consequence of the combination of surface melting and evaporation mechanisms. It is also shown that in the subsurface, below the melted layer, the martensitic transformation was triggered due to the effects of the thermal stresses and shock waves propagating in the material.

  7. 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

  8. Entropy balance in holographic superconductors

    E-Print Network [OSTI]

    Sean A. Hartnoll; Razieh Pourhasan

    2012-05-07

    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.

  9. Entropy bounds for uncollapsed matter

    E-Print Network [OSTI]

    Abreu, Gabriel

    2010-01-01

    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.

  10. Entropy bounds for uncollapsed matter

    E-Print Network [OSTI]

    Gabriel Abreu; Matt Visser

    2010-11-19

    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.

  11. Metal alloy identifier

    DOE Patents [OSTI]

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

    1987-01-01

    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.

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

    E-Print Network [OSTI]

    Yu, K. M.

    2010-01-01

    acceptable solar response and efficiency and sufficient5,6] and high efficiency hybrid solar cells [7,8]. Into design high efficiency multijunction solar cells [37,38

  13. Simple Extractors for All MinEntropies and a New Pseudorandom Generator #

    E-Print Network [OSTI]

    Shaltiel, Ronen

    from a distribution with sufficiently high min­entropy and a short random seed produces an output generator'' is an algorithm that given a short random seed produces a long output that is computationallySimple Extractors for All Min­Entropies and a New Pseudorandom Generator # Ronen Shaltiel

  14. 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...

  15. 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...

  16. 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...

  17. 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.

    1980-05-01

    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.

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

    E-Print Network [OSTI]

    Yu, K. M.

    2010-01-01

    Highly Mismatched Crystalline and Amorphous GaN 1-x As xrange of 0.17crystalline outside this region.is long enough to form crystalline lattices with uniform

  19. 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)

    1986-09-16

    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.

  20. A Comprehensive Comparison of Shannon Entropy and Smooth Renyi Entropy

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    , is the fundamental concept in information theory and cryptography. There exists many entropy definitions] is extremely useful in information theory, the use of much more conservative measures, like min optimization techniques, applied to characterize worst case distributions, and the use of the Lambert W

  1. RADIATION ENTROPY FLUX AND ENTROPY PRODUCTION OF THE EARTH SYSTEM

    E-Print Network [OSTI]

    solar radiation entropy flux among the dif- ferent expressions arises mainly from the difference and rising sea level [Intergovernmental Panel on Climate Change (IPCC), 2007]. The major cause is most likely and for con- straining future detrimental climate changes. Development of such strategies requires accurate

  2. Cesium iodide alloys

    DOE Patents [OSTI]

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

    1992-01-01

    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.

  3. Disentangling geometric and dissipative origins of negative Casimir entropies

    E-Print Network [OSTI]

    Stefan Umrath; Michael Hartmann; Gert-Ludwig Ingold; Paulo A. Maia Neto

    2015-07-21

    Dissipative electromagnetic response and scattering geometry are potential sources for the appearance of a negative Casimir entropy. We show that the dissipative contribution familiar from the plane-plane geometry appears also in the plane-sphere and the sphere-sphere geometries and adds to the negative Casimir entropy known to exist in these geometries even for perfectly reflecting objects. Taking the sphere-sphere geometry as an example, we carry out a scattering-channel analysis which allows to distinguish between the contributions of different polarizations. We demonstrate that dissipation and geometry share a common feature making possible negative values of the Casimir entropy. In both cases there exists a scattering channel whose contribution to the Casimir free energy vanishes in the high-temperature limit. While the mode-mixing channel is associated with the geometric origin, the transverse electric channel is associated with the dissipative origin of the negative Casimir entropy. By going beyond the Rayleigh limit, we find even for large distances that negative Casimir entropies can occur also for Drude-type metals provided the dissipation strength is sufficiently small.

  4. Entropy production by simple electrical circuits

    E-Print Network [OSTI]

    E. N. Miranda; S. Nikolskaia

    2012-08-13

    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

  5. Irradiation assisted stress corrosion cracking of HTH Alloy X-750 and Alloy 625

    SciTech Connect (OSTI)

    Mills, W.J.; Lebo, M.R.; Bajaj, R.; Kearns, J.J.; Hoffman, R.C.; Korinko, J.J.

    1994-06-01

    In-reactor testing of bolt-loaded precracked compact tension specimens was performed in 360{degree}C water to determine effect of irradiation on the SCC behavior of HTH Alloy X-750 and direct aged Alloy 625. Out-of-flux and autoclave control specimens provided baseline data. Primary test variables were stress intensity factor, fluence, chemistry, processing history, prestrain. Results for the first series of experiments were presented at a previous conference. Data from two more recent experiments are compared with previous results; they confirm that high irradiation levels significantly reduce SCC resistance in HTH Alloy X-750. Heat-to-heat differences in IASCC were related to differences in boron content, with low boron heats showing improved SCC resistance. The in-reactor SCC performance of Alloy 625 was superior to that for Alloy X-750, as no cracking was observed in any Alloy 625 specimens even though they were tested at very high K{sub 1} and fluence levels. A preliminary SCC usage model developed for Alloy X-750 indicates that in-reactor creep processes, which relax stresses but also increase crack tip strain rates, and radiolysis effects accelerate SCC. Hence, in-reactor SCC damage under high flux conditions may be more severe than that associated with postirradiation tests. In addition, preliminary mechanism studies were performed to determine the cause of IASCC In Alloy X-750.

  6. 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)

    1996-12-01

    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.}

  7. Holographic Studies of Entanglement Entropy in Superconductors

    E-Print Network [OSTI]

    Tameem Albash; Clifford V. Johnson

    2012-05-31

    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. Generalized Gravitational Entropy from Total Derivative Action

    E-Print Network [OSTI]

    Dong, Xi

    2015-01-01

    We investigate the generalized gravitational entropy from total derivative terms in the gravitational action. Following the method of Lewkowycz and Maldacena, we find that the generalized gravitational entropy from total derivatives vanishes. We compare our results with the work of Astaneh, Patrushev, and Solodukhin. We find that if total derivatives produced nonzero entropy, the holographic and the field-theoretic universal terms of entanglement entropy would not match. Furthermore, the second law of thermodynamics could be violated if the entropy of total derivatives did not vanish.

  9. Information inequalities and Generalized Graph Entropies

    E-Print Network [OSTI]

    Sivakumar, Lavanya

    2012-01-01

    In this article, we discuss the problem of establishing relations between information measures assessed for network structures. Two types of entropy based measures namely, the Shannon entropy and its generalization, the R\\'{e}nyi entropy have been considered for this study. Our main results involve establishing formal relationship, in the form of implicit inequalities, between these two kinds of measures when defined for graphs. Further, we also state and prove inequalities connecting the classical partition-based graph entropies and the functional-based entropy measures. In addition, several explicit inequalities are derived for special classes of graphs.

  10. Wettability of brazing alloys on molybdenum and TZM (Mo-Ti-Zr alloy)

    SciTech Connect (OSTI)

    McDonald, M.M.; Keller, D.L.; Heiple, C.R.; Hofmann, W.E.

    1988-01-01

    Vacuum brazing studies have been performed on molybdenum and TZM (0.5Ti-0.08Zr-Mo). Wettability tests have been conducted for nineteen braze metal filler alloys on molybdenum and thirty-two braze metal filler alloys on TZM over a wide range of temperatures. A wetting index, which is a function of contact angle and braze alloy contact area, was determined for each filler alloy at each brazing temperature. The nature and extent of interaction between the brazing alloys and the base metals was analyzed by conventional metallography, scanning-electron microscopy, and electron microprobe analysis. A comparison is made between the behavior of filler alloys on molybdenum and TZM -- filler alloys consistently exhibited less wettability on TZM than on molybdenum. The lower wettability of TZM is believed to be due to a small amount of titanium in the surface oxide on TZM. Cracking was observed in the base metal under some of the high temperature braze deposits. The cracking is shown to arise from liquid metal embrittlement from nickel in the high temperature braze alloys. 7 refs., 11 figs., 2 tabs.

  11. Corrosion fatigue crack growth in clad low-alloy steel. Part 2, Water flow rate effects in high sulfur plate steel

    SciTech Connect (OSTI)

    James, L.A; Lee, H.B.; Wire, G.L.; Novak, S.R.; Cullen, W.H.

    1996-04-01

    Corrosion fatigue crack propagation tests were conducted on a high- sulfur ASTM A302-B plate steel overlaid with weld-deposited Alloy EN82H cladding. The specimens featured semi-elliptical surface cracks penetrating approximately 6.3 mm of cladding into the underlying steel. The initial crack sizes were relatively large with surface lengths of 22.8--27.3 mm, and depths of 10.5--14.1 mm. The experiments were initiated in a quasi-stagnant low-oxygen (O{sub 2} < 10 ppb) aqueous environment at 243{degrees}C, under loading conditions ({Delta}K, R, cyclic frequency) conducive to environmentally-assisted cracking (EAC) under quasi-stagnant conditions. Following fatigue testing under quasi-stagnant conditions where EAC was observed, the specimens were then fatigue tested under conditions where active water flow of either 1.7 m/sec. or 4.7 m/sec. was applied parallel to the crack. Earlier experiments on unclad surface-cracked specimens of the same steel exhibited EAC under quasi- stagnant conditions, but water flow rates at 1.7 m/sec. and 5.0 m/sec. parallel to the crack mitigated EAC. In the present experiments on clad specimens, water flow at approximately the same as the lower of these velocities did not mitigate EAC, and a free stream velocity approximately the same as the higher of these velocities resulted in sluggish mitigation of EAC. The lack of robust EAC mitigation was attributed to the greater crack surface roughness in the cladding interfering with flow induced within the crack cavity. An analysis employing the computational fluid dynamics code, FIDAP, confirmed that frictional forces associated with the cladding crack surface roughness reduced the interaction between the free stream and the crack cavity.

  12. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

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

    2012-06-12

    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.

  13. Solid solution lithium alloy cermet anodes

    DOE Patents [OSTI]

    Richardson, Thomas J.

    2013-07-09

    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.

  14. VOLUME 77, NUMBER 17 P H Y S I C A L R E V I E W L E T T E R S 21 OCTOBER 1996 Gap States in Dilute Magnetic Alloy Superconductors

    E-Print Network [OSTI]

    Jarrell, Mark

    alloy superconductors and used the maximum entropy method (MEM) [6] to obtain the superconducting Magnetic Alloy Superconductors Woonki Chung* and Mark Jarrell Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221-0011 (Received 1 July 1996) We study states in the superconducting gap

  15. Processing of Iridium and Iridium Alloys

    SciTech Connect (OSTI)

    Ohriner, Evan Keith [ORNL

    2008-01-01

    Iridium and its alloys have been considered to be difficult to fabricate due to their high melting temperatures, limited ductility, sensitivity to impurity content, and chemical properties. The variety of processing methods used for iridium and its alloys are reviewed, including purification, melting, forming, joining, and powder metallurgy techniques. Also included are coating and forming by the methods of electroplating, chemical and physical vapor deposition, and melt particle deposition.

  16. Oxidation of advanced steam turbine alloys

    SciTech Connect (OSTI)

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

    2006-03-01

    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.

  17. Oxidation of alloys for advanced steam turbines

    SciTech Connect (OSTI)

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.

    2005-01-01

    Ultra supercritical (USC) 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.

  18. Cold worked ferritic alloys and components

    DOE Patents [OSTI]

    Korenko, Michael K. (Wexford, PA)

    1984-01-01

    This invention relates to liquid metal fast breeder reactor and steam generator precipitation hardening fully ferritic alloy components which have a microstructure substantially free of the primary precipitation hardening phase while having cells or arrays of dislocations of varying population densities. It also relates to the process by which these components are produced, which entails solution treating the alloy followed by a final cold working step. In this condition, the first significant precipitation hardening of the component occurs during high temperature use.

  19. New developments in hardfacing alloys

    SciTech Connect (OSTI)

    Menon, R.

    1996-02-01

    The hardfacing industry has matured substantially since its inception in the early 1920s. Numerous welding alloys have been developed and field proven. By developing a strong working knowledge of available alloys, wear conditions and the specific wear situation, the goal of selecting the proper alloy to prolong service life and fight wear is now more attainable than ever. Hardfacing is the process in which a coating or cladding is applied to a substrate for the main purpose of reducing wear or loss of material by abrasion, impact, erosion, galling and cavitation. Most service environments involve a combination of these factors. The choice of an alloy system depends to a great degree on the nature of the wear process encountered. This can range from a simple low-stress condition to a very complex situation that involves abrasion combined with a corrodant and high temperature. The list of possible wear conditions is outlined below: (1) low-stress abrasion, (2) high-stress abrasion, (3) impact, (4) metal-to-metal wear, (5) erosion, and (6) cavitation erosion. In general, service conditions involve a combination of several of the conditions listed above. In addition to the type of wear, three other factors are also important as far as the severity of the wear condition is concerned. These are: (1) type of abradant, (2) service temperature, and (3) service environment. It is clear that in terms of the nature of the wear process as well as the environmental conditions, service conditions are extremely complex. They are, therefore, difficult to simulate in the laboratory. The selection of hardfacing alloys for an application is based primarily on actual field experiences and these are refined with data gathered with time.

  20. Black Holes And Their Entropy 

    E-Print Network [OSTI]

    Mei, Jianwei

    2010-10-12

    . . . . . . . . . 21 1. Solutions in Four Dimensions . . . . . . . . . . . . . . 22 2. Solutions in Higher Dimensions . . . . . . . . . . . . . 27 C. Black Hole Solutions in Supergravity Theories . . . . . . . 30 D. Plebanski-Demianski Type Solutions in d = 5... is to discuss the construction of new black hole solutions and the calculation of the black hole entropy. In Chapter II, we shall re- port some new black hole solutions that we have found during the past few years [21, 22, 23] and we will discuss some...

  1. Journal of Alloys and Compounds 492 (2010) 166172 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Gubicza, Jenõ

    2010-01-01

    ratio and excellent corrosion resistance [1]. This alloy is often used as a raw material for structural components in automobile and aircraft industries. The relatively high strength of AZ91 alloy can

  2. X-ray diffraction study on the microstructure of a MgZnY alloy consolidated by high-pressure torsion

    E-Print Network [OSTI]

    Gubicza, Jenõ

    effect. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Mg alloys are important raw materials-pressure torsion Péter Jenei a , Jen}o Gubicza a, , Eun Yoo Yoon b , Hyoung Seop Kim b a Department of Materials Physics, Eötvös Loránd University, Budapest, P.O.B. 32, H-1518, Hungary b Department of Materials Science

  3. On quantum Rényi entropies: A new generalization and some properties

    SciTech Connect (OSTI)

    Müller-Lennert, Martin; Dupuis, Frédéric; Szehr, Oleg; Fehr, Serge; Tomamichel, Marco

    2013-12-15

    The Rényi entropies constitute a family of information measures that generalizes the well-known Shannon entropy, inheriting many of its properties. They appear in the form of unconditional and conditional entropies, relative entropies, or mutual information, and have found many applications in information theory and beyond. Various generalizations of Rényi entropies to the quantum setting have been proposed, most prominently Petz's quasi-entropies and Renner's conditional min-, max-, and collision entropy. However, these quantum extensions are incompatible and thus unsatisfactory. We propose a new quantum generalization of the family of Rényi entropies that contains the von Neumann entropy, min-entropy, collision entropy, and the max-entropy as special cases, thus encompassing most quantum entropies in use today. We show several natural properties for this definition, including data-processing inequalities, a duality relation, and an entropic uncertainty relation.

  4. 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)

    2003-04-08

    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.

  5. Uranium-titanium-niobium alloy

    DOE Patents [OSTI]

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

    1990-01-01

    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.

  6. 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)

    2001-01-01

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

  7. 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)

    1999-04-20

    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.

  8. Synthesis of alloys with controlled phase structure

    DOE Patents [OSTI]

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

    1999-04-20

    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.

  9. Low activation ferritic alloys

    DOE Patents [OSTI]

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

    1986-01-01

    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.

  10. Low activation ferritic alloys

    DOE Patents [OSTI]

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

    1985-02-07

    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.

  11. 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

  12. Entropy generation in a chemical reaction

    E-Print Network [OSTI]

    E. N. Miranda

    2012-08-10

    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.

  13. Entropy in an Arc Plasma Source

    SciTech Connect (OSTI)

    Kaminska, A.; Dudeck, M

    2008-03-19

    The entropy properties in a D.C. argon arc plasma source are studied. The local thermodynamical entropy relations are established for a set of uniform sub-systems (Ar, Ar{sup +}, e) in order to deduce the entropy balance equation in presence of dissipative effects and in the case of a thermal non equilibrium. Phenomenological linear laws are deduced in near equilibrium situation. The flow parameters inside the plasma source are calculated by a Navier-Stokes fluid description taking into account a thermal local non equilibrium. The entropy function is calculated in the plasma source using the values of the local variables obtained from the numerical code.

  14. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

    Anderson, Iver E; Rieken, Joel

    2013-12-10

    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.

  15. Entropy 2008, 10, 71-99; DOI: 10.3390/entropy-e10020071 OPEN ACCESS

    E-Print Network [OSTI]

    Bienenstock, Elie

    the fundamental information-processing tasks performed by the brain. In many of these studies, the entropy.mdpi.org/entropy Article Estimating the Entropy of Binary Time Series: Methodology, Some Theory and a Simulation Study Yun, Greece 3 Division of Applied Mathematics and Department of Neuroscience, Brown University, Providence, RI

  16. Optics and Lasers in Engineering 46 (2008) 2733 Entropy generation rate during laser pulse heating: Effect of laser

    E-Print Network [OSTI]

    Al-Qahtani, Hussain M.

    2008-01-01

    Optics and Lasers in Engineering 46 (2008) 27­33 Entropy generation rate during laser pulse heating generation rate attains high values in the early heating period due to large (1/T 2 ). Moreover, the laser reserved. Keywords: Laser; Pulse; Temperature; Entropy generation rate 1. Introduction Laser pulse heating

  17. Tsallis Entropy Based Velocity Distribution in Open Channel Flows 

    E-Print Network [OSTI]

    Luo, Hao

    2010-07-14

    The Tsallis entropy is applied to derive both 1-D and 2-D velocity distributions in an open channel cross section. These distributions contain a parameter m through which the Tsallis entropy becomes a generalization of the Shannon entropy. Different...

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

    DOE Patents [OSTI]

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

    1996-06-11

    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.

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

    DOE Patents [OSTI]

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

    1996-01-01

    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.

  20. 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)

    2013-09-01

    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}.

  1. Cesium iodide alloys

    DOE Patents [OSTI]

    Kim, H.E.; Moorhead, A.J.

    1992-12-15

    A transparent, strong CsI alloy is described having additions of monovalent iodides. Although the preferred iodide is AgI, RbI and CuI additions also contribute to an improved polycrystalline CsI alloy with outstanding multispectral infrared transmittance properties. 6 figs.

  2. 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)

    2004-05-04

    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.

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

    E-Print Network [OSTI]

    Foley, David Christopher

    2014-07-01

    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 ...

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

    E-Print Network [OSTI]

    Dibbern, Jennifer C

    2007-01-01

    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 ...

  5. Alloys in energy development

    SciTech Connect (OSTI)

    Frost, B.R.T.

    1984-02-01

    The development of new and advanced energy systems often requires the tailoring of new alloys or alloy combinations to meet the novel and often stringent requirements of those systems. Longer life at higher temperatures and stresses in aggressive environments is the most common goal. Alloy theory helps in achieving this goal by suggesting uses of multiphase systems and intermediate phases, where solid solutions were traditionally used. However, the use of materials under non-equilibrium conditions is now quite common - as with rapidly solidified metals - and the application of alloy theory must be modified accordingly. Under certain conditions, as in a reactor core, the rate of approach to equilibrium will be modified; sometimes a quasi-equilibrium is established. Thus an alloy may exhibit enhanced general diffusion at the same time as precipitate particles are being dispersed and solute atoms are being carried to vacancy sinks. We are approaching an understanding of these processes and can begin to model these complex systems.

  6. Motivation : Information Work and Money Understanding entropy

    E-Print Network [OSTI]

    Cockshott, W. Paul

    Motivation : Information Work and Money Understanding entropy Our Results/Contribution Babbage,University of Glasgow SICSA Conf, 2011 Author, WPC Information and production #12;Motivation : Information Work and Money Understanding entropy Our Results/Contribution Outline 1 Motivation : Information Work and Money

  7. MAXIMUM ENTROPY APPROACH TO OPTIMAL SENSOR PLACEMENT

    E-Print Network [OSTI]

    Kreinovich, Vladik

    MAXIMUM ENTROPY APPROACH TO OPTIMAL SENSOR PLACEMENT FOR AEROSPACE NON-DESTRUCTIVE TESTING R discussed for space struc- tures. Key words: Non-destructive testing, maximum entropy, aerospace structures not have a sufficient number of them, so additional sensors must be placed to test the structural integrity

  8. Boltzmann-Shannon Entropy: Generalization and Application

    E-Print Network [OSTI]

    C. G. Chakrabarti; Indranil Chakrabarty

    2006-10-20

    The paper deals with the generalization of both Boltzmann entropy and distribution in the light of most-probable interpretation of statistical equilibrium. The statistical analysis of the generalized entropy and distribution leads to some new interesting results of significant physical importance.

  9. Fractal Statistics and Quantum Black Hole Entropy

    E-Print Network [OSTI]

    Wellington da Cruz

    2000-11-18

    Simple considerations about the fractal characteristic of the quantum-mechanical path give us the opportunity to derive the quantum black hole entropy in connection with the concept of fractal statistics. We show the geometrical origin of the numerical factor of four of the quantum black hole entropy expression and the statistics weight appears as a counting of the quanta of geometry.

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

    DOE Patents [OSTI]

    Natesan, K.

    1992-01-01

    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.

  11. Observation of second-phase particles in bulk zirconium alloys using synchrotron radiation q

    E-Print Network [OSTI]

    Motta, Arthur T.

    Observation of second-phase particles in bulk zirconium alloys using synchrotron radiation q Abstract To further advance the mechanistic understanding of microstructural evolution in zirconium alloys the growth kinetics of second-phase particles in zirconium alloys. The high energy ¯ux, energy resolution

  12. Investigation of Microscale Damage Evolution in High-Strength...

    Office of Scientific and Technical Information (OSTI)

    Alloy. Citation Details In-Document Search Title: Investigation of Microscale Damage Evolution in High-Strength Al Alloy. Authors: Jin, Huiqing ; Lu, Wei-Yang ; Mota, Alejandro ;...

  13. Investigation of Microscale Damage Evolution in High Strength...

    Office of Scientific and Technical Information (OSTI)

    Alloy. Citation Details In-Document Search Title: Investigation of Microscale Damage Evolution in High Strength A1 Alloy. Authors: Jin, Huiqing ; Lu, Wei-Yang ; Mota, Alejandro ;...

  14. Entanglement Entropy at Large Central Charge

    E-Print Network [OSTI]

    Thomas Hartman

    2013-03-27

    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.

  15. 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)

    1984-01-01

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

  16. In situ investigation of high humidity stress corrosion cracking of 7075 aluminum alloy by three-dimensional (3D) X-ray synchrotron tomography

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

    Singh, S. S.; Williams, J. J.; Lin, M. F.; Xiao, X.; De Carlo, F.; Chawla, N.

    2014-05-14

    In situ X-ray synchrotron tomography was used to investigate the stress corrosion cracking behavior of under-aged Al–Zn–Mg–Cu alloy in moisture. The discontinuous surface cracks (crack jumps) mentioned in the literature are actually a single continuous and tortuous crack when observed in three dimension (3D). Contrary to 2D measurements made at the surface which suggest non-uniform crack growth rates, 3D measurements of the crack length led to a much more accurate measurement of crack growth rates.

  17. Fe-based long range ordered alloys

    DOE Patents [OSTI]

    Liu, Chain T (Oak Ridge, TN); Inouye, Henry (Oak Ridge, TN); Schaffhauser, Anthony C. (Oak Ridge, TN)

    1980-01-01

    Malleable long range ordered alloys having high critical ordering temperatures exist in the V(Co,Fe).sub.3 and V(Co,Fe,Ni).sub.3 system having the composition comprising by weight 22-23% V, 35-50% Fe, 0-22% Co and 19-40% Ni with an electron density no greater than 8.00. Excellent high temperature properties occur in alloys having compositions comprising by weight 22-23% V, 35-45% Fe, 0-10% Co, 25-35% Ni; 22-23% V, 28-33% Ni and the remainder Fe; and 22-23% V, 19-22% Ni, 19-22% Co and the remainder Fe. The alloys are fabricable by casting, deforming and annealing for sufficient time to provide ordered structure.

  18. Development Program for Natural Aging Aluminum Casting Alloys

    SciTech Connect (OSTI)

    Dr. Geoffrey K. Sigworth

    2004-05-14

    A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

  19. Retention of Conformational Entropy upon Calmodulin Binding to Target Peptides is Driven by Transient Salt Bridges

    SciTech Connect (OSTI)

    Smith, Dayle MA; Straatsma, TP; Squier, Thomas C.

    2012-10-03

    Calmodulin (CaM) is a highly flexible calcium-binding protein that mediates signal transduction through an ability to differentially bind to highly variable binding sequences in target proteins. To identify how binding affects CaM motions, and its relationship to conformational entropy and target peptide sequence, we have employed fully atomistic, explicit solvent molecular dynamics simulations of unbound CaM and CaM bound to five different target peptides. The calculated CaM conformational binding entropies correlate with experimentally derived conformational entropies with a correlation coefficient R2 of 0.95. Selected side-chain interactions with target peptides restrain interhelical loop motions, acting to tune the conformational entropy of the bound complex via widely distributed CaM motions. In the complex with the most conformational entropy retention (CaM in complex with the neuronal nitric oxide synthase binding sequence), Lys-148 at the C-terminus of CaM forms transient salt bridges alternating between Glu side chains in the N-domain, the central linker, and the binding target. Additional analyses of CaM structures, fluctuations, and CaM-target interactions illuminate the interplay between electrostatic, side chain, and backbone properties in the ability of CaM to recognize and discriminate against targets by tuning its conformational entropy, and suggest a need to consider conformational dynamics in optimizing binding affinities.

  20. 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.; Gotardo, R. A. M.; Viana, D. S. F.; Garcia, D.; Eiras, J. A.

    2014-09-21

    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.

  1. Expanding the Area of Gravitational Entropy

    E-Print Network [OSTI]

    R. B. Mann

    2002-11-12

    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. Decrease of Entropy and Chemical Reactions

    E-Print Network [OSTI]

    Yi-Fang Chang

    2008-07-01

    The chemical reactions are very complex, and include oscillation, condensation, catalyst and self-organization, etc. In these case changes of entropy may increase or decrease. The second law of thermodynamics is based on an isolated system and statistical independence. If fluctuations magnified due to internal interactions exist in the system, entropy will decrease possibly. In chemical reactions there are various internal interactions, so that some ordering processes with decrease of entropy are possible on an isolated system. For example, a simplifying Fokker-Planck equation is solved, and the hysteresis as limit cycle is discussed.

  3. Comprehensive Investigation of the Uranium-Zirconium Alloy System: Thermophysical Properties, Phase Characterization and Ion Implantation Effects 

    E-Print Network [OSTI]

    Ahn, Sangjoon

    2013-07-31

    Uranium-zirconium (U-Zr) alloys comprise a class of metallic nuclear fuel that is regularly considered for application in fast nuclear energy systems. The U-10wt%Zr alloy has been demonstrated to very high burnup without ...

  4. Domain growth in alloys 

    E-Print Network [OSTI]

    Hawick, Kenneth Arthur

    1991-01-01

    This thesis describes Monte-Carlo computer simulations of binary alloys, with comparisons between small angle neutron scattering (SANS) data, and numerically integrated solutions to the Cahn-Hilliard-Cook (CHC) equation. ...

  5. 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

    2013-01-01

    with silicon carbide hollow spheres (SiCHS) is investigated for quasi-static (10-3 s-1 ) and high strain rate into reduced fuel consumption. Reduction in the weight of aircraft and marine vessels can lead to increased

  6. Entropy Change in the Carnot Cycle: Entropy in the Adiabatic Process

    E-Print Network [OSTI]

    Kazumi Suematsu

    2012-06-24

    Entropy change in the Carnot cycle is discussed. In particular, the isentropic change in the adiabatic expansion (or compression) is reinvestigated.

  7. Entropy Change in the Carnot Cycle: Entropy in the Adiabatic Process

    E-Print Network [OSTI]

    Suematsu, Kazumi

    2012-01-01

    Entropy change in the Carnot cycle is discussed. In particular, the isentropic change in the adiabatic expansion (or compression) is reinvestigated.

  8. Method of treating intermetallic alloy hydrogenation/oxidation catalysts for improved impurity poisoning resistance, regeneration and increased activity

    DOE Patents [OSTI]

    Wright, R.B.

    1992-01-14

    Alternate, successive high temperature oxidation and reduction treatments, in either order, of intermetallic alloy hydrogenation and intermetallic alloy oxidation catalysts unexpectedly improves the impurity poisoning resistance, regeneration capacity and/or activity of the catalysts. The particular alloy, and the final high temperature treatment given alloy (oxidation or reduction) will be chosen to correspond to the function of the catalyst (oxidation or hydrogenation). 23 figs.

  9. 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 ...

  10. Entanglement Entropy of Magnetic Electron Stars

    E-Print Network [OSTI]

    Tameem Albash; Clifford V. Johnson; Scott MacDonald

    2015-04-08

    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.

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

    E-Print Network [OSTI]

    Thiel, Gregory P

    2012-01-01

    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 ...

  12. Discontinuous Galerkin Finite Element Method for the Nonlinear Hyperbolic Problems with Entropy-Based Artificial Viscosity Stabilization 

    E-Print Network [OSTI]

    Zingan, Valentin Nikolaevich

    2012-07-16

    This work develops a discontinuous Galerkin finite element discretization of non- linear hyperbolic conservation equations with efficient and robust high order stabilization built on an entropy-based artificial viscosity approximation...

  13. 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

    2014-10-27

    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.

  14. 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)

    2010-03-23

    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.

  15. Dispersoid reinforced alloy powder and method of making

    DOE Patents [OSTI]

    Anderson, Iver E; Terpstra, Robert L

    2014-10-21

    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.

  16. The entropy power inequality for quantum systems

    E-Print Network [OSTI]

    Robert Koenig; Graeme Smith

    2014-02-20

    When two independent analog signals, X and Y are added together giving Z=X+Y, the entropy of Z, H(Z), is not a simple function of the entropies H(X) and H(Y), but rather depends on the details of X and Y's distributions. Nevertheless, the entropy power inequality (EPI), which states that exp [2H(Z)] \\geq exp[2H(X)] + exp[2H(Y)], gives a very tight restriction on the entropy of Z. This inequality has found many applications in information theory and statistics. The quantum analogue of adding two random variables is the combination of two independent bosonic modes at a beam splitter. The purpose of this work is to give a detailed outline of the proof of two separate generalizations of the entropy power inequality to the quantum regime. Our proofs are similar in spirit to standard classical proofs of the EPI, but some new quantities and ideas are needed in the quantum setting. Specifically, we find a new quantum de Bruijin identity relating entropy production under diffusion to a divergence-based quantum Fisher information. Furthermore, this Fisher information exhibits certain convexity properties in the context of beam splitters.

  17. 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.

    2014-12-10

    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...

  18. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01

    xAsx Alloys for Multi-junction Solar Cells. in PVSC '10.for single and multi-junction solar cells along with thematerial system multi-junction solar cell [12]. High quality

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

    DOE Patents [OSTI]

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

    1985-10-28

    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.

  20. Preparation and characterization of highly L2{sub 1}-ordered full-Heusler alloy Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} thin films for spintronics device applications

    SciTech Connect (OSTI)

    Wang Wenhong; Sukegawa, Hiroaki; Shan Rong; Furubayashi, Takao; Inomata, Koichiro

    2008-06-02

    We report the investigation of structure and magnetic properties of full-Heusler alloy Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} (CFAS) thin films grown on MgO-buffered MgO (001) substrates through magnetron sputtering. It was found that single-crystal CFAS thin films with high degree of L2{sub 1} ordering and sufficiently flat surface could be obtained after postdeposition annealing. All the films show a distinct uniaxial magnetic anisotropy with the easy axis of magnetization along the in-plane [110] direction. These results indicate that the use of the MgO buffer for CFAS is a promising approach for achieving a higher tunnel magnetoresistance ratio, and thus for spintronics device applications.

  1. Microstructures and oxidation behavior of some Molybdenum based alloys

    SciTech Connect (OSTI)

    Ray, Pratik Kumar

    2010-12-15

    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.

  2. Rigorous and General Definition of Thermodynamic Entropy

    E-Print Network [OSTI]

    Gian Paolo Beretta; Enzo Zanchini

    2010-10-05

    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.

  3. 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

    2003-08-19

    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.

  4. Magnetocaloric effects in Er1?xTbxAl2 alloys

    SciTech Connect (OSTI)

    Khan, Mahmud; Gschneidner, Jr., K.A.; Pecharsky, V.K.

    2010-04-21

    The magnetocaloric properties of the (Er{sub 1-x}Tb{sub x})Al{sub 2} alloys have been evaluated by magnetization and heat capacity measurements. It is shown that by partial substitution of Er by Tb the ferromagnetic ordering temperature of (Er{sub 1-x}Tb{sub x})Al{sub 2} can be tuned over a wide range of temperatures, that is from 13 K (ErAl{sub 2}) to 110 K (TbAl{sub 2}). Over the entire temperature range the alloy system exhibits large magnetocaloric effect. For a field change of 5 T, the observed magnetic entropy changes peaks from -18 J/kg K (x = 0.20) to -12 J/kg K (x = 0.90). The adiabatic temperature changes measured for selected alloys in the series show a maximum value of 6 K when the magnetic field is changed from 0 to 5 T.

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

    SciTech Connect (OSTI)

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

    2012-03-01

    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.

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

    DOE Patents [OSTI]

    Natesan, K.; Baxter, D.J.

    1983-07-26

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

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

    DOE Patents [OSTI]

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

    1984-01-01

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

  8. Entropy bounds for uncollapsed rotating bodies

    E-Print Network [OSTI]

    Abreu, Gabriel

    2010-01-01

    Entropy bounds in black hole physics, based on a wide variety of different approaches, have had a long and distinguished history. Recently the current authors have turned attention to uncollapsed systems and obtained a robust entropy bound for uncollapsed static spherically symmetric configurations. In the current article we extend this bound to rotating systems. This extension is less simple than one might at first suppose. Purely classically, (using only classical general relativity and basic thermodynamics), it is possible to show that the entropy of uncollapsed matter inside a region enclosed by a surface of area A is bounded from above by S = max kappa(FIDOs) / (2 pi). Thus, using only classical general relativity, basic thermodynamics, and the Unruh effect, we are able to argue that for uncollapsed matter S <= {1/2} A.

  9. Zipf's law, power laws, and maximum entropy

    E-Print Network [OSTI]

    Visser, Matt

    2012-01-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines - from astronomy to demographics to economics to linguistics to zoology, and even warfare. A recent model of random group formation [RGF] attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present article I argue that the cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.

  10. Multi-range force sensors utilizing shape memory alloys

    DOE Patents [OSTI]

    Varma, Venugopal K. (Knoxville, TN)

    2003-04-15

    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.

  11. Quinary metallic glass alloys

    DOE Patents [OSTI]

    Lin, X.; Johnson, W.L.

    1998-04-07

    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.

  12. Quinary metallic glass alloys

    DOE Patents [OSTI]

    Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    1998-01-01

    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.

  13. Entropy and the Typicality of Universes

    E-Print Network [OSTI]

    Julian Barbour; Tim Koslowski; Flavio Mercati

    2015-07-24

    The universal validity of the second law of thermodynamics is widely attributed to a finely tuned initial condition of the universe. This creates a problem: why is the universe atypical? We suggest that the problem is an artefact created by inappropriate transfer of the traditional concept of entropy to the whole universe. Use of what we call the relational $N$-body problem as a model indicates the need to employ two distinct entropy-type concepts to describe the universe. One, which we call entaxy, is novel. It is scale-invariant and decreases as the observable universe evolves. The other is the algebraic sum of the dimensionful entropies of branch systems (isolated subsystems of the universe). This conventional additive entropy increases. In our model, the decrease of entaxy is fundamental and makes possible the emergence of branch systems and their increasing entropy. We have previously shown that all solutions of our model divide into two halves at a unique `Janus point' of maximum disorder. This constitutes a common past for two futures each with its own gravitational arrow of time. We now show that these arrows are expressed through the formation of branch systems within which conventional entropy increases. On either side of the Janus point, this increase is in the same direction in every branch system. We also show that it is only possible to specify unbiased solution-determining data at the Janus point. Special properties of these `mid-point data' make it possible to develop a rational theory of the typicality of universes whose governing law, as in our model, dictates the presence of a Janus point in every solution. If our self-gravitating universe is governed by such a law, then the second law of thermodynamics is a necessary direct consequence of it and does not need any special initial condition.

  14. 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)

    2014-08-15

    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.

  15. Diffusion Bonding Aluminium Alloys and Composites: New Approaches and Modelling

    E-Print Network [OSTI]

    Shirzadi Ghoshouni, Amir Abbas

    1998-07-10

    alloy in the early years of this century, aluminium alloys have been of interest because of their high strength-to-weight ratio, formability, corrosion resistance and long-term durability. The first all-aluminium aeroplane was manufactured in 1920... reinforcement (i.e. discontinuously reinforced aluminium, DRA) are now available commercially. The use of Al/SiC composites has reduced the production costs and improved the performance of aircraft components, Materials Progress (1997). However, despite...

  16. Entropy, Nonequilibrium, Chaos and Infinitesimals Giovanni Gallavotti 1

    E-Print Network [OSTI]

    and of the associated concept of entropy, [1]. At the time, since the works of Bernoulli, Avogadro, Herapath, Waterstone

  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)

    1990-01-01

    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. 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)

    1994-05-02

    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.

  19. Characterization of several kinds of quantum analogues of relative entropy

    E-Print Network [OSTI]

    Masahito Hayashi

    2005-12-20

    Quantum relative entropy $D(\\rho\\|\\sigma)\\defeq\\Tr \\rho (\\log \\rho- \\log \\sigma)$ plays an important role in quantum information and related fields. However, there are many quantum analogues of relative entropy. In this paper, we characterize these analogues from information geometrical viewpoint. We also consider the naturalness of quantum relative entropy among these analogues.

  20. ENTROPY OF BOGOLIUBOV AUTOMORPHISMS OF CAR AND CCR

    E-Print Network [OSTI]

    Neshveyev, Sergey

    ENTROPY OF BOGOLIUBOV AUTOMORPHISMS OF CAR AND CCR ALGEBRAS WITH RESPECT TO QUASI-FREE STATES Sergey V. Neshveyev Abstract We compute the dynamical entropy of Bogoliubov automorphisms of CAR and CCR for the entropy of Bogoliubov automorphisms of the CAR-algebra with respect to quasi-free states obtained

  1. Algorithms for optimized maximum entropy and diagnostic tools for analytic continuation

    E-Print Network [OSTI]

    Bergeron, Dominic

    2015-01-01

    Analytic continuation of numerical data obtained in imaginary time or frequency has become an essential part of many branches of quantum computational physics. The maximum-entropy approach is the most widely used method whenever the data contains some numerical uncertainties, especially in Monte-Carlo based calculations. Here we present a highly optimized approach to maximum-entropy implemented in a freely available software that is both fast and accurate and offers quality-of-fit diagnostic tools. It can handle fermionic and bosonic input Green functions, self-energies, or correlation functions, both in Matsubara frequency or imaginary time, and with arbitrary covariance. All aspects of the implementation critical for accuracy and speed are optimized using specific numerical methods. A new way of choosing the optimal value of the entropy weight $\\alpha$ is also introduced. It is based on the identification of three different regimes in the value of $\\chi^2$ as a function of $\\alpha$: Large values of $\\alpha$...

  2. Quantum Entropy of Charged Rotating Black Holes

    E-Print Network [OSTI]

    R. B. Mann

    1996-07-10

    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.

  3. The effect of entropy on macroions adsorption

    E-Print Network [OSTI]

    Felipe Jimenez-Angeles; Marcelo Lozada-Cassou

    2003-03-25

    We study macroion adsorption on planar surfaces, through a simple model. The importance of entropy in the interfacial phenomena is stressed. Our results are in qualitative agreement with available computer simulations and experimental results on charge reversal and self-assembling at interfaces.

  4. Cyclic thermodynamic processes and entropy production

    E-Print Network [OSTI]

    Liouvillean. We then show that the entropy production per cycle is (strictly) positive, a property that implies Carnot's formulation of the second law of thermodynamics. 1 Introduction During the past several, we make a contribution to this program by studying Carnot's for­ mulation of the second law

  5. 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

  6. 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...

  7. 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

    2003-04-22

    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.

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

    E-Print Network [OSTI]

    A. Bialas; W. Czyz; K. Zalewski

    2006-10-30

    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.

  9. Filler metal alloy for welding cast nickel aluminide alloys

    DOE Patents [OSTI]

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

    1998-01-01

    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.

  10. Filler metal alloy for welding cast nickel aluminide alloys

    DOE Patents [OSTI]

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

    1998-03-10

    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.

  11. Maximum-Entropy Inference with a Programmable Annealer

    E-Print Network [OSTI]

    Nicholas Chancellor; Szilard Szoke; Walter Vinci; Gabriel Aeppli; Paul A. Warburton

    2015-06-26

    Optimisation problems in science and engineering typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this approach maximises the likelihood that the solution found is correct. An alternative approach is to make use of prior statistical information about the noise in conjunction with Bayes's theorem. The maximum entropy solution to the problem then takes the form of a Boltzmann distribution over the ground and excited states of the cost function. Here we use a programmable Josephson junction array for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that maximum entropy decoding at finite temperature can in certain cases give competitive and even slightly better bit-error-rates than the maximum likelihood approach at zero temperature, confirming that useful information can be extracted from the excited states of the annealing device. Furthermore we introduce a microscopic bit-by-bit analytical method which is agnostic to the specific application and use it to show that the annealing device samples from a highly Boltzmann-like distribution. Machines of this kind are therefore candidates for use in a wide variety of machine learning applications which exploit maximum entropy inference, including natural language processing and image recognition. We further show that the limiting factor for performance in our experiments is likely to be control errors rather than failure to reach equilibrium. Our work also provides a method for determining if a system is in equilibrium which can be easily generalized. We discuss possible applications of this method to spin glasses and probing the performance of the quantum annealing algorithm.

  12. Electrodeposition of nickel-chromium-phosphorous alloys in the presence of additives 

    E-Print Network [OSTI]

    Bindlish, Rahul

    1991-01-01

    practical applications because of their unique properties. They are chemically and structurally homoge- neous (1, 2). They are mechanically hard and have an extremely high tensile strength. They are single-phase alloys without long range crystalline order... was utilized in order to determine the effect of these additives on the surface morphology of the electrodeposited alloy. The crystallinity of the deposited material was determined by X-ray diffraction. Corrosion testing of the deposited alloy was carried...

  13. Supplementary balance laws and the entropy principle

    E-Print Network [OSTI]

    Serge Preston

    2010-08-01

    In this work we study the mathematical aspects of the development in the continuum thermodynamics known as the "Entropy Principle". It started with the pioneering works of B.Coleman, W.Noll and I. Muller in 60th of XX cent. and got its further development mostly in the works of G. Boillat, I-Shis Liu and T.Ruggeri. "Entropy Principle" combines in itself the structural requirement on the form of balance laws of the thermodynamical system (denote such system $(\\mathcal{C})$) and on the entropy balance law with the convexity condition of the entropy density. First of these requirements has pure mathematical form defining so called "supplementary balance laws" (shortly SBL) associated with the original balance system. Vector space of SBL can be considered as a kind of natural "closure" of the original balance system. This space includes the original balance laws, the entropy balance, the balance laws corresponding to the symmetries of the balance system and some other balance equations. We consider the case of Rational Extended Thermodynamics where densities, fluxes and sources of the balance equations do not depend on the derivatives of physical fields $y^i$. We present the basic structures of RET: Lagrange-Liu equations,"main fields", and dual formulation of the balance system. We obtain and start studying the defining system of equations for the density $h^0$ of a supplementary balance law. This overdetermined linear system of PDE of second order determines all the densities $h^0$ and with them, due to the formalism of RET, the fluxes and sources of SBL. Solvability conditions of defining system delivers the constitutive restrictions on the balance equations of the original balance system. We illustrate our results by some simple examples of balance system and by describing all the supplementary balance laws and the constitutive restrictions for the Cattaneo heat propagation system.

  14. Theoretical Studies of Hydrogen Storage Alloys.

    SciTech Connect (OSTI)

    Jonsson, Hannes

    2012-03-22

    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.

  15. A Computationally Based Approach to Homogenizing Advanced Alloys

    SciTech Connect (OSTI)

    Jablonski, P D; Cowen, C J

    2011-02-27

    We have developed a computationally based approach to optimizing the homogenization heat treatment of complex alloys. The Scheil module within the Thermo-Calc software is used to predict the as-cast segregation present within alloys, and DICTRA (Diffusion Controlled TRAnsformations) is used to model the homogenization kinetics as a function of time, temperature and microstructural scale. We will discuss this approach as it is applied to both Ni based superalloys as well as the more complex (computationally) case of alloys that solidify with more than one matrix phase as a result of segregation. Such is the case typically observed in martensitic steels. With these alloys it is doubly important to homogenize them correctly, especially at the laboratory scale, since they are austenitic at high temperature and thus constituent elements will diffuse slowly. The computationally designed heat treatment and the subsequent verification real castings are presented.

  16. Tensile and toughness assessment of the procured advanced alloys

    SciTech Connect (OSTI)

    Tan, Lizhen; Sokolov, Mikhail A.; Hoelzer, David T.; Busby, Jeremy T.

    2015-09-11

    Life extension of the existing nuclear reactors imposes irradiation of high fluences to structural materials, resulting in significant challenges to the traditional reactor materials such as type 304 and 316 stainless steels. Advanced alloys with superior radiation resistance will increase safety margins, design flexibility, and economics for not only the life extension of the existing fleet but also new builds with advanced reactor designs. The Electric Power Research Institute (EPRI) teamed up with Department of Energy (DOE) to initiate the Advanced Radiation Resistant Materials (ARRM) program, aiming to develop and test degradation resistant alloys from current commercial alloy specifications by 2021 to a new advanced alloy with superior degradation resistance by 2024 in light water reactor (LWR)-relevant environments

  17. Shape memory alloy actuator

    DOE Patents [OSTI]

    Varma, Venugopal K. (Knoxville, TN)

    2001-01-01

    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.

  18. Duct and cladding alloy

    DOE Patents [OSTI]

    Korenko, Michael K. (Rockville, MD)

    1983-01-01

    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.

  19. Immersion studies on candidate container alloys for the Tuff Repository

    SciTech Connect (OSTI)

    Beavers, J.A.; Durr, C.L.

    1991-05-01

    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.

  20. 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.

    2011-10-01

    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.

  1. 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...

  2. 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

    2012-10-01

    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.

  3. WEAR RESISTANT ALLOYS FOR COAL HANDLING EQUIPMENT

    E-Print Network [OSTI]

    Bhat, M.S.

    2011-01-01

    Proceedings of the Conference on Coal Feeding Systems, HeldWear Resistant Alloys for Coal Handling Equipment", proposalWear Resistant Alloys for Coal Handling Equi pment". The

  4. Solid Solution Lithium Alloy Cermet Anodes

    E-Print Network [OSTI]

    Richardson, Thomas J.; Chen, Guoying

    2006-01-01

    Solid Solution Lithium Alloy Cermet Anodes Thomas J.94720 USA Abstract Lithium-magnesium solid solution alloysHeating mixtures of lithium nitride and magnesium provides a

  5. 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.

    2013-02-20

    V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and elastic properties of 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.

  6. 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

    2014-01-01

    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.

  7. TWO-BODY, DRY ABRASIVE WEAR OF Fe/Cr/C EXPERIMENTAL ALLOYS ---RELATIONSHIP BETWEEN MICROSTRUCTURE AND MECHANICAL PROPERTIES

    E-Print Network [OSTI]

    Kwok, C.K.S.

    2010-01-01

    Preparation and Heat Treatment (1) Experimental alloys. Thecooled. Three different heat treatments were applied to thelater section. Basically, the heat treatment invol.v.ed high

  8. Mold, flow, and economic considerations in high temperature precision casting

    E-Print Network [OSTI]

    Humbert, Matthew S

    2013-01-01

    Casting high temperature alloys that solidify through a noticeable two phase region, specifically platinum-ruthenium alloys, is a particularly challenging task due to their high melting temperature and this necessitates ...

  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. Effects of microstructure on mixed-mode, high-cycle fatigue crack-growth thresholds in Ti-6Al-4V alloy

    E-Print Network [OSTI]

    Ritchie, Robert

    O D U C T IO N The control of failures owing to high-cycle fatigue (HCF) in turbine-engine for such HCF failures. Indeed, there are many fatigue-critical locations within the turbine engine where- ing HCF failures in turbine engines, it is critical that fatigue crack-growth thresholds are well

  11. Potential automotive uses of wrought magnesium alloys

    SciTech Connect (OSTI)

    Gaines, L.; Cuenca, R.; Wu, S. [Argonne National Lab., IL (United States); Stodolsky, F. [Argonne National Lab., IL (United States)]|[Argonne National Lab., Washington, DC (United States)

    1996-06-01

    Vehicle weight reduction is one of the major means available to improve automotive fuel efficiency. High-strength steels, aluminum (Al), and polymers are already being used to reduce weight significantly, but substantial additional reductions could be achieved by greater use of low-density magnesium (Mg) and its alloys. Mg alloys are currently used in relatively small quantities for auto parts, generally limited to die castings (e.g., housings). Argonne National Laboratory`s Center for Transportation Research has performed a study for the Lightweight Materials Program within DOE`s Office of Transportation Materials to evaluate the suitability of wrought Mg and its alloys to replace steel/aluminum for automotive structural and sheet applications. Mg sheet could be used in body nonstructural and semi-structural applications, while extrusions could be used in such structural applications as spaceframes. This study identifies high cost as the major barrier to greatly increased Mg use in autos. Two technical R and D areas, novel reduction technology and better hot-forming technology, could enable major cost reductions.

  12. 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)

    1989-01-01

    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.

  13. Radiation resistant austenitic stainless steel alloys

    DOE Patents [OSTI]

    Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

    1987-02-11

    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.

  14. Shape memory alloy thaw sensors

    DOE Patents [OSTI]

    Shahinpoor, Mohsen (Albuquerque, NM); Martinez, David R. (Albuquerque, NM)

    1998-01-01

    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.

  15. High Quality Epitaxial Growth of GaAsyP1-y Alloys on Si1-xGex Virtual P. Sharma, M. T. Bulsara, and E. A. Fitzgerald

    E-Print Network [OSTI]

    in an appropriate temperature window, could produce high-quality GaAs thin films on Ge. Over a range of growth, tandem solar cell designs on Si. Despite the lattice-matched condition of GaP on Si, low defect density less than 106 /cm2 ) has not been reported in the literature [1-4]. In contrast, the analogous GaAs

  16. Understanding shape entropy through local dense packing

    E-Print Network [OSTI]

    Greg van Anders; Daphne Klotsa; N. Khalid Ahmed; Michael Engel; Sharon C. Glotzer

    2014-10-28

    Entropy drives the phase behavior of colloids ranging from dense suspensions of hard spheres or rods to dilute suspensions of hard spheres and depletants. Entropic ordering of anisotropic shapes into complex crystals, liquid crystals, and even quasicrystals has been demonstrated recently in computer simulations and experiments. The ordering of shapes appears to arise from the emergence of directional entropic forces (DEFs) that align neighboring particles, but these forces have been neither rigorously defined nor quantified in generic systems. Here, we show quantitatively that shape drives the phase behavior of systems of anisotropic particles upon crowding through DEFs. We define DEFs in generic systems, and compute them for several hard particle systems. We show that they are on the order of a few kT at the onset of ordering, placing DEFs on par with traditional depletion, van der Waals, and other intrinsic interactions. In experimental systems with these other interactions, we provide direct quantitative evidence that entropic effects of shape also contribute to self-assembly. We use DEFs to draw a distinction between self-assembly and packing behavior. We show that the mechanism that generates directional entropic forces is the maximization of entropy by optimizing local particle packing. We show that this mechanism occurs in a wide class of systems, and we treat, in a unified way, the entropy-driven phase behavior of arbitrary shapes incorporating the well-known works of Kirkwood, Onsager, and Asakura and Oosawa.

  17. Wedlable nickel aluminide alloy

    DOE Patents [OSTI]

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

    2002-11-19

    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.

  18. Dyonic AdS_4 black hole entropy and attractors via entropy function

    E-Print Network [OSTI]

    Goulart, Prieslei

    2015-01-01

    Using the Sen's entropy function formalism, we compute the entropy for the extremal dyonic black hole solutions of theories in the presence of dilaton field coupled to the field strength and a dilaton potential. We solve the attractor equations analytically and determine the near horizon metric, the value of the scalar fields and the electric field on the horizon, and consequently the entropy of these black holes. The attractor mechanism plays a very important role for these systems, and after studying the simplest systems involving dilaton fields, we propose a general ansatz for the value of the scalar field on the horizon, which allows us to solve the attractor equations for gauged supergravity theories in AdS_4 spaces.

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

    SciTech Connect (OSTI)

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

    2010-08-01

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

  20. NUCLEATION IN A TWO COMPONENT METAL ALLOY

    E-Print Network [OSTI]

    Sander, Evelyn

    NUCLEATION IN A TWO COMPONENT METAL ALLOY Kalea Sebesta Department of Applied Mathematics, known as nucleation, in a two component metal alloy. The motivation behind this study is to use component metal alloys. These alloys are seen in material sciences; therefore, understanding

  1. Geometric entropy and edge modes of the electromagnetic field

    E-Print Network [OSTI]

    William Donnelly; Aron C. Wall

    2015-06-18

    We calculate the vacuum entanglement entropy of Maxwell theory in a class of curved spacetimes by Kaluza-Klein reduction of the theory onto a two-dimensional base manifold. Using two-dimensional duality, we express the geometric entropy of the electromagnetic field as the entropy of a tower of scalar fields, constant electric and magnetic fluxes, and a contact term, whose leading order divergence was discovered by Kabat. The complete contact term takes the form of one negative scalar degree of freedom confined to the entangling surface. We show that the geometric entropy agrees with a statistical definition of entanglement entropy that includes edge modes: classical solutions determined by their boundary values on the entangling surface. This resolves a longstanding puzzle about the statistical interpretation of the contact term in the entanglement entropy. We discuss the implications of this negative term for black hole thermodynamics and the renormalization of Newton's constant.

  2. 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.

    2011-10-11

    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.

  3. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S.; Alman, David E.

    2002-11-05

    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

  4. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S. (Corvallis, OR); Alman, David E. (Salem, OR)

    2002-11-05

    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

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

    E-Print Network [OSTI]

    I. B. Khriplovich

    2002-03-31

    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.

  6. Holography, Dark Energy and Entropy of Large Cosmic Structures

    E-Print Network [OSTI]

    C. Sivaram; Kenath Arun

    2013-03-15

    As is well known, black hole entropy is proportional to the area of the horizon suggesting a holographic principle wherein all degrees of freedom contributing to the entropy reside on the surface. In this note, we point out that large scale dark energy (such as a cosmological constant) constraining cosmic structures can imply a similar situation for the entropy of a hierarchy of such objects.

  7. ADVANCES IN CHARACTERIZATION OF MATERIALS: ALLOYS AND CERAMICS

    E-Print Network [OSTI]

    Thomas, Gareth

    2011-01-01

    OF MATERIALS: ALLOYS AND CERAMICS Gareth Thomas May 1978OF MATERIALS : ALLOYS AND CERAMICS Gareth Thomas Departmentand alloys and many ceramics, point resolutions better than

  8. Irradiation-assisted stress corrosion cracking of HTH Alloy X-750 and Alloy 625

    SciTech Connect (OSTI)

    Bajaj, R.; Mills, W.J.; Lebo, M.R.; Hyatt, B.Z.; Burke, M.G.

    1995-07-01

    In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water. New data confirms previous results that high irradiation levels reduce SCC resistance in Alloy X-750. Low boron heats show improved IASCC (irradiation-assisted stress corrosion cracking). Alloy 625 is resistant to IASCC. Microstructural, microchemical, and deformation studies were carried out. Irradiation of X-750 caused significant strengthening and ductility loss associated with formation of cavities and dislocation loops. High irradiation did not cause segregation in X-750. Irradiation of 625 resulted in formation of small dislocation loops and a fine body-centered-orthorhombic phase. The strengthening due to loops and precipitates was apparently offset in 625 by partial dissolution of {gamma} precipitates. Transmutation of boron to helium at grain boundaries, coupled with matrix strengthening, is believed to be responsible for IASCC in X-750, and the absence of these two effects results in superior IASCC resistance in 625.

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

    SciTech Connect (OSTI)

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

    2008-12-01

    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.

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

    E-Print Network [OSTI]

    Peter Hugo Nelson

    2014-09-13

    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.

  11. Improved Maximum Entropy Analysis with an Extended Search Space

    E-Print Network [OSTI]

    Alexander Rothkopf

    2013-01-07

    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.

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

    E-Print Network [OSTI]

    Umberto Lucia

    2010-11-17

    This paper develops an analytical and rigorous formulation of the maximum entropy generation principle. The result is suggested as the Fourth Law of Thermodynamics.

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

    E-Print Network [OSTI]

    Hermanowicz, Slawomir W

    2005-01-01

    of entropy-energy definition of sustainability as well asto assess the sustainability is based on the energy. Thisand Energy: Toward a Definition of Physical Sustainability

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

    E-Print Network [OSTI]

    Hermanowicz, Slawomir W

    2005-01-01

    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

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

    E-Print Network [OSTI]

    Wung-Hong Huang

    2014-11-11

    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.

  16. The Effects of Quantum Entropy on the Bag Constant

    E-Print Network [OSTI]

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

    2003-01-01

    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.

  17. Communication: The simplified generalized entropy theory of glass...

    Office of Scientific and Technical Information (OSTI)

    Communication: The simplified generalized entropy theory of glass-formation in polymer melts Citation Details In-Document Search This content will become publicly available on...

  18. 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)

    2006-10-03

    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.

  19. 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

    2014-04-01

    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.

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

    E-Print Network [OSTI]

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

    2015-04-10

    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.

  1. Statistical optimization for passive scalar transport: maximum entropy production vs maximum Kolmogorov-Sinay entropy

    E-Print Network [OSTI]

    Martin Mihelich; Berengere Dubrulle; Didier Paillard; Davide Faranda

    2015-05-26

    We derive rigorous results on the link between the principle of maximum entropy production and the principle of maximum Kolmogorov-Sinai entropy using a Markov model of the passive scalar diffusion called the Zero Range Process. We show analytically that both the entropy production and the Kolmogorov-Sinai entropy seen as functions of f admit a unique maximum denoted fmaxEP and fmaxKS. The behavior of these two maxima is explored as a function of the system disequilibrium and the system resolution N. The main result of this article is that fmaxEP and fmaxKS have the same Taylor expansion at _rst order in the deviation of equilibrium. We find that fmaxEP hardly depends on N whereas fmaxKS depends strongly on N. In particular, for a fixed difference of potential between the reservoirs, fmaxEP (N) tends towards a non-zero value, while fmaxKS (N) tends to 0 when N goes to infinity. For values of N typical of that adopted by Paltridge and climatologists we show that fmaxEP and fmaxKS coincide even far from equilibrium. Finally, we show that one can find an optimal resolution N_ such that fmaxEP and fmaxKS coincide, at least up to a second order parameter proportional to the non-equilibrium uxes imposed to the boundaries.

  2. Thermodynamic entropy is the Noether invariant

    E-Print Network [OSTI]

    Sasa, Shin-ichi

    2015-01-01

    We study a classical many-particle system with an external control represented by a time dependent parameter in a Lagrangian. We show that thermodynamic entropy of the system is the Noether invariant associated with a symmetry for an infinitesimal non-uniform time translation $t\\to t+\\eta\\hbar \\beta$, where $\\eta$ is a small parameter, $\\hbar$ is the Planck constant, $\\beta$ is the inverse temperature that depends on the energy, and trajectories in the phase space are restricted to those consistent with quasi-static processes in thermodynamics.

  3. 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 ...

  4. [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 ...

  5. Scanning Probe Alloying Nanolithography (SPAN) 

    E-Print Network [OSTI]

    Lee, Hyungoo

    2010-07-14

    nanowires has been developed. The new technique is called the Scanning Probe Alloying Nanolithography (SPAN). The SPAN was processed using an Atomic Force Microscope (AFM) in ambient environment. Firstly, an AFM probe was coated with gold (Au), and then slid...

  6. The Effect of Cold Work on Properties of Alloy 617

    SciTech Connect (OSTI)

    Richard Wright

    2014-08-01

    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.

  7. Shape memory alloy thaw sensors

    DOE Patents [OSTI]

    Shahinpoor, M.; Martinez, D.R.

    1998-04-07

    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.

  8. Fluctuation Theorems for Entropy Production and Heat Dissipation in Periodically Driven Markov Chains

    E-Print Network [OSTI]

    Shargel, Benjamin Hertz; Chou, Tom

    2009-01-01

    entropy production of the continuous process do not simplycontinuous and strictly convex good rate function of the entropy production under the backward process.

  9. RELAP-7 Numerical Stabilization: Entropy Viscosity Method

    SciTech Connect (OSTI)

    R. A. Berry; M. O. Delchini; J. Ragusa

    2014-06-01

    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.

  10. Strong converse theorems using Rényi entropies

    E-Print Network [OSTI]

    Felix Leditzky; Nilanjana Datta

    2015-06-08

    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.

  11. Hydrodynamic equations for electrons in graphene obtained from the maximum entropy principle

    SciTech Connect (OSTI)

    Barletti, Luigi

    2014-08-15

    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.

  12. Highly Mismatched Semiconductor Alloys with Extreme Compositions

    E-Print Network [OSTI]

    Levander, Alejandro X.

    2012-01-01

    applications to solar energy conversion. Data for As-richespecially in solar energy conversion devices. Subsequent

  13. 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

  14. ANNEALING BEHAVIOR OF HIGH PERMEABILITY AMORPHOUS ALLOYS

    E-Print Network [OSTI]

    Rabenberg, L.

    2010-01-01

    C. A. Pampillo and D. E. Polk, Mat. Sci. Eng. , 33, 275 (Cambridge, 1976). D. E. Polk and B. C. Giessen, in Metallic1979). A. J. Kerns, D. E. Polk, R. Ray, B. C. Giessen, Mat.

  15. Phase transition of holographic entanglement entropy in massive gravity

    E-Print Network [OSTI]

    Zeng, Xiao-Xiong; Li, Li-Fang

    2015-01-01

    The phase structure of holographic entanglement entropy is studied in massive gravity for the quantum systems with finite and infinite volumes, which in the bulk is dual to calculate the minimal surface area for a black hole and black brane respectively. In the entanglement entropy$-$temperature plane, we find for both the black hole and black brane there is a Van der Waals-like phase transition as the case in thermal entropy$-$temperature plane. That is, there is a first order phase transition for the small charge and a second order phase transition at the critical charge. For the first order phase transition, the equal area law is checked and for the second order phase transition, the critical exponent of the heat capacity is obtained. All the results show that the phase structure of holographic entanglement entropy is the same as that of thermal entropy regardless of the volume of the spacetime on the boundary.

  16. Dual-Phase Hot-Press Forming Alloy

    E-Print Network [OSTI]

    Cambridge, University of

    Dual-Phase Hot-Press Forming Alloy Hongliang Yi and H. K. D. H. Bhadeshia 23 April, 2010 heat treatment: ferrite+pearlite · After heat treatment: martensite · Mechanical property: UTS ~1500 strength for anti-intrusion · Shortages: low ductility for energy absorption · Solution: keeping the high

  17. Present Status of Vanadium Alloys for Fusion Applications

    SciTech Connect (OSTI)

    Muroga, Takeo; Chen, J. M.; Chernov, V. M.; Kurtz, Richard J.; Le Flem, M.

    2014-12-01

    Vanadium alloys are advanced options for low activation structural materials. After more than two decades of research, V-4Cr-4Ti has been emerged as the leading candidate, and technological progress has been made in reducing the number of critical issues for application of vanadium alloys to fusion reactors. Notable progress has been made in fabricating alloy products and weld joints without degradation of properties. Various efforts are also being made to improve high temperature strength and creep-rupture resistance, low temperature ductility after irradiation, and corrosion resistance in blanket conditions. Future research should focus on clarifying remaining uncertainty in the operating temperature window of V-4Cr-4Ti for application to near to middle term fusion blanket systems, and on further exploration of advanced materials for improved performance for longer-term fusion reactor systems.

  18. Effect of irradiation on the stress corrosion cracking behavior of Alloy X-750 and Alloy 625

    SciTech Connect (OSTI)

    Mills, W.J.; Lebo, M.R.; Kearns, J.J.; Hoffman, R.C.; Korinko, J.J.; Luther, R.F.; Sykes, G.B.

    1993-10-01

    In-reactor testing of bolt-loaded precracked and as-notched compact tension specimens was performed in 360{degrees}C water to determine effect of irradiation on SCC of Condition HTH and Condition BH Alloy X-750 and age-hardened Alloy 625. Variables were stress intensity factor (K{sub I}) level, fluence, grade of HTH material, prestraining and material chemistry. Effects of irradiation on high temperature SCC and the rapid cracking that occurs during cooldown below 150{degrees}C were characterized. Significant degradation in the in-reactor SCC resistance of HTH material was observed at initial K{sub I} levels above 30 MPa{radical}m and fluences greater than 10{sup 19} n/cm{sup 2} (E > 1 MeV). A small degradation in SCC resistance of HTH material was observed at low fluences (<10{sup 16} n/cm{sup 2}). As-notched specimens displayed less degradation in SCC resistance than precracked specimens. Prestraining greatly improved in-flux and out-of-flux SCC resistance of HTH material, as little or no SCC was observed in precracked specimens prestrained 20 to 30%, whereas extensive cracking was observed in nonprestrained specimens. Condition HTH heats with low boron (10 ppM or less) had improved in-reactor SCC resistance compared to heats with high and intermediate boron (>20 ppM). Age-hardened Alloy 625 exhibited superior in-reactor SCC behavior compared to HTH material as no crack extension occurred in any of the precracked Alloy 625 specimens tested at initial K{sub I} levels up to 80 MPa{radical}m.

  19. 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

    2011-06-01

    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.

  20. The permutation entropy rate equals the metric entropy rate for ergodic information sources and ergodic dynamical systems

    E-Print Network [OSTI]

    Jose M. Amigo; Matthew B. Kennel; Ljupco Kocarev

    2005-03-21

    Permutation entropy quantifies the diversity of possible orderings of the values a random or deterministic system can take, as Shannon entropy quantifies the diversity of values. We show that the metric and permutation entropy rates--measures of new disorder per new observed value--are equal for ergodic finite-alphabet information sources (discrete-time stationary stochastic processes). With this result, we then prove that the same holds for deterministic dynamical systems defined by ergodic maps on $n$% -dimensional intervals. This result generalizes a previous one for piecewise monotone interval maps on the real line (Bandt, Keller and Pompe, "Entropy of interval maps via permutations",\\textit{Nonlinearity} \\textbf{15}, 1595-602, (2002)), at the expense of requiring ergodicity and using a definition of permutation entropy rate differing in the order of two limits. The case of non-ergodic finite-alphabet sources is also studied and an inequality developed. Finally, the equality of permutation and metric entropy rates is extended to ergodic non-discrete information sources when entropy is replaced by differential entropy in the usual way.

  1. Liquid-Solid Phase Transition Alloy as Reversible and Rapid Molding Bone Cement

    E-Print Network [OSTI]

    Yi, Liting; Liu, Jing

    2013-01-01

    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...

  2. Radioactive material package closures with the use of shape memory alloys

    SciTech Connect (OSTI)

    Koski, J.A.; Bronowski, D.R.

    1997-11-01

    When heated from room temperature to 165 C, some shape memory metal alloys such as titanium-nickel alloys have the ability to return to a previously defined shape or size with dimensional changes up to 7%. In contrast, the thermal expansion of most metals over this temperature range is about 0.1 to 0.2%. The dimension change of shape memory alloys, which occurs during a martensite to austenite phase transition, can generate stresses as high as 700 MPa (100 kspi). These properties can be used to create a closure for radioactive materials packages that provides for easy robotic or manual operations and results in reproducible, tamper-proof seals. This paper describes some proposed closure methods with shape memory alloys for radioactive material packages. Properties of the shape memory alloys are first summarized, then some possible alternative sealing methods discussed, and, finally, results from an initial proof-of-concept experiment described.

  3. Hard and tough electrodeposited aluminum-manganese alloys with tailored nanostructures

    E-Print Network [OSTI]

    Ruan, Shiyun

    2010-01-01

    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 ...

  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. Stress corrosion cracking and crack tip characterization of Alloy X-750 in light water reactor environments

    E-Print Network [OSTI]

    Gibbs, Jonathan Paul

    2011-01-01

    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 ...

  6. Effect of Strain Rate and Temperature on Fracture and Damage of Magnesium Alloy AZ31B 

    E-Print Network [OSTI]

    Rodriguez Atencio, Ana Karina

    2015-04-29

    Due to their low density and high specific strength, magnesium and its alloys are structural metals attractive for the aerospace and automotive industries. However, wide spread use of wrought magnesium is challenged by its ...

  7. 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 ...

  8. Evaluation of Quasicrystal Al-Cu-Fe Alloys for Tribological Applications 

    E-Print Network [OSTI]

    Nabelsi, Nezar

    2013-07-22

    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

    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. 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.

    design requires the use of interconnectors in the SOFC stack that provide mechanical support to the cell and on relatively expensive high Cr superalloys have been used as interconnector materials.2 However, lowering for interconnector applications, alumina or silica formers are not suitable. Fe­Cr-based alloys less than 24 wt % Cr

  11. Material synthesis and hydrogen storage of palladium-rhodium alloy.

    SciTech Connect (OSTI)

    Lavernia, Enrique J.; Yang, Nancy Y. C.; Ong, Markus D.

    2011-08-01

    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.

  12. CREEP AND CREEP-FATIGUE OF ALLOY 617 WELDMENTS

    SciTech Connect (OSTI)

    Wright, Jill; Carroll, Laura; Wright, Richard

    2014-08-01

    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).

  13. Space applications of shape memory alloys 

    E-Print Network [OSTI]

    Godard, Olivier Jean

    2002-01-01

    This work presents an investigation of two new possible space applications of shape memory alloys. The first application uses these alloys as active devices to optimally reorient solar panels in space. The thermal issues related to the actuation...

  14. CuInSe2 and its alloys are the leading choice for absorber layers in high-efficiency thin film solar cells due to their direct gap, high absorption coefficient and

    E-Print Network [OSTI]

    Rockett, Angus

    in CuInSe2. Epitaxial CuInSe2 thin films were deposited on GaAs bicrystal substrates using a hybrid film solar cells due to their direct gap, high absorption coefficient and excellent thermal stability epilayers to the GaAs bicrystal substrate. This allows isolation and optical characterization of individual

  15. Microstructural Development and Mechanical Properties for Reactive Air Brazing of ZTA to Ni Alloys using Ag-CuO Braze Alloys

    SciTech Connect (OSTI)

    Prevost, Erica; DeMarco, A.Joseph; MacMichael, Beth; Joshi, Vineet V.; Meier, Alan; Hoffman, John W.; Walker, William J.

    2014-12-01

    Reactive air brazing (RAB) is a potential joining technique to join metal alloys to ceramics for a variety of applications. In the current study, nickel (Ni) alloys were heat treated to form an oxide layer prior to RAB joining to zirconia toughened alumina (ZTA). The Ni alloys evaluated were Nicrofer 6025 HT, Inconel 600, Inconel 693, Haynes 214 and Inconel 601. The ZTA studied had compositions of 0 to 15 wt% zirconia and 0 to 14 wt% glass. Four point-bend tests were performed to evaluate the joint strength of ZTA/ZTA and ZTA/nickel alloys brazed with Ag-2wt% CuO braze alloys. It was determined that the joint strength is not a function of the ZTA composition, but that the strength is a strong function of the chemistry and microstructure of the oxide layer formed on the nickel alloy. It was determined that an increase in the aluminum content of the Ni alloy resulted in an increase of the thickness of alumina in the oxide layer and was directly proportional to the bond strength with the exception of Inconel 601 which exhibited relatively high joint strengths even though it had a relatively low aluminum content.

  16. Crossed products and entropy of automorphisms

    E-Print Network [OSTI]

    Ciprian Pop; Roger R. Smith

    2003-04-16

    Let A be an exact C^*-algebra, let G be a locally compact group, and let (A,G,\\alpha) be a C*-dynamical system. Each automorphism \\alpha_g induces a spatial automorphism Ad_{\\lamba_g} on the reduced crossed product A\\times_\\alpha G. In this paper we examine the question, first raised by E. Stormer, of when the topological entropies of \\alpha_g and Ad_{\\alpha_g} coincide. This had been answered by N. Brown for the particular case of discrete abelian groups. Using different methods, we extend his result to a wider class of groups called locally [FIA]^-. This class includes all abelian groups, both discrete and continuous, as well as all compact groups.

  17. Fast Fermi Acceleration and Entropy Growth

    E-Print Network [OSTI]

    Tiago Pereira; Dmitry Turaev

    2015-03-13

    Fermi acceleration is the process of energy transfer from massive objects in slow motion to light objects that move fast. The model for such process is a time-dependent Hamiltonian system. As the parameters of the system change with time, the energy is no longer conserved, which makes the acceleration possible. One of the main problems is how to generate a sustained and robust energy growth. We show that the non-ergodicity of any chaotic Hamiltonian system must universally lead to the exponential growth of energy at a slow periodic variation of parameters. We build a model for this process in terms of a Geometric Brownian Motion with a positive drift and relate it to the entropy increase.

  18. Entropy-energy inequalities for qudit states

    E-Print Network [OSTI]

    Armando Figueroa; Julio López; Octavio Castaños; Ramón López-Peña; Margarita A. Man'ko; Vladimir I. Man'ko

    2014-12-08

    We establish a procedure to find the extremal density matrices for any finite Hamiltonian of a qudit system. These extremal density matrices provide an approximate description of the energy spectra of the Hamiltonian. In the case of restricting the extremal density matrices by pure states, we show that the energy spectra of the Hamiltonian is recovered for $d=2$ and $3$. We conjecture that by means of this approach the energy spectra can be recovered for the Hamiltonian of an arbitrary finite qudit system. For a given qudit system Hamiltonian, we find new inequalities connecting the mean value of the Hamiltonian and the entropy of an arbitrary state. We demonstrate that these inequalities take place for both the considered extremal density matrices and generic ones.

  19. Nickel aluminide alloys with improved weldability

    DOE Patents [OSTI]

    Santella, M.L.; Goodwin, G.M.

    1995-05-09

    Weldable nickel aluminide alloys which are essentially free, if not entirely free, of weld hot cracking are provided by employing zirconium concentrations in these alloys of greater than 2.6 wt. % or sufficient to provide a substantial presence of Ni--Zr eutectic phase in the weld so as to prevent weld hot cracking. Weld filler metals formed from these so modified nickel aluminide alloys provide for crack-free welds in previously known nickel aluminide alloys. 5 figs.

  20. Nickel aluminide alloys with improved weldability

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); Goodwin, Gene M. (Lenior City, TN)

    1995-05-09

    Weldable nickel aluminide alloys which are essentially free, if not entirely free, of weld hot cracking are provided by employing zirconium concentrations in these alloys of greater than 2.6 wt. % or sufficient to provide a substantial presence of Ni--Zr eutectic phase in the weld so as to prevent weld hot cracking. Weld filler metals formed from these so modified nickel aluminide alloys provide for crack-free welds in previously known nickel aluminide alloys.

  1. Configurational Entropy in Brane-world Models: A New Approach to Stability

    E-Print Network [OSTI]

    R. A. C. Correa; Roldao da Rocha

    2015-02-10

    In this work we investigate the entropic information on thick brane-worlds scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model is and hence the brane-world entropic information measure is shown an accurate way for providing the most suitable values for the bulk AdS curvature. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the system configuration, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.

  2. Configurational Entropy in Brane-world Models: A New Approach to Stability

    E-Print Network [OSTI]

    Correa, R A C

    2015-01-01

    In this work we investigate the entropic information on thick brane-worlds scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model is and hence the brane-world entropic information measure is shown an accurate way for providing the most suitable values for the bulk AdS curvature. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the system configuration, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.

  3. Towards Radiation Tolerant Nanostructured Ferritic Alloys

    SciTech Connect (OSTI)

    Miller, Michael K [ORNL; Hoelzer, David T [ORNL; Russell, Kaye F [ORNL

    2010-01-01

    The high temperature and irradiation response of a new class of nanostructured ferritic alloys have been investigated by atom probe tomography. These materials are candidate materials for use in the extreme environments that will be present in the next generation of power generating systems. Atom probe tomography has revealed that the yttria powder is forced into solid solution during the mechanical alloying process andsubsequently 2-nm-diameter Ti-, Y- and O-enriched nanoclusters are formedduring the extrusion process. These nanoclusters have been shown to be remarkably stable during isothermal annealing treatments up to 0.92 of the melting temperature and during proton irradiation up to 3 displacements per atom. No significant difference in sizes, compositions and number densities of the nanoclusters was also observed between the unirradiated and proton irradiated conditions. The grain boundaries were found to have high number densities of nanoclusters as well as chromium and tungsten segregation which pin the grain boundary to minimize creep and grain growth.

  4. Entropy of quantum channel in the theory of quantum information

    E-Print Network [OSTI]

    Wojciech Roga

    2011-10-03

    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.

  5. 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]/[In+Ga]SubstrateCrystalSample *Negligible amount of Ga diffused into back of film from substrate; not detectable by EDX Device structure GaAs(In,Ga)SePhotoluminescence Excitation Spectroscopy of Cu(In,Ga)Se22 Thin FilmsThin Films Damon Hebert, Julio Soares, Marie Mayer, Angus

  6. General proof of entropy principle in Einstein-Maxwell theory

    E-Print Network [OSTI]

    Fang, Xiongjun

    2015-01-01

    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.

  7. Multiscale Modeling of Grain Boundary Segregation and Embrittlement in Tungsten for Mechanistic Design of Alloys for Coal Fired Plants

    SciTech Connect (OSTI)

    Luo, Jian; Tomar, Vikas; Zhou, Naixie; Lee, Hongsuk

    2013-06-30

    Based on a recent discovery of premelting-like grain boundary segregation in refractory metals occurring at high temperatures and/or high alloying levels, this project investigated grain boundary segregation and embrittlement in tungsten (W) based alloys. Specifically, new interfacial thermodynamic models have been developed and quantified to predict high-temperature grain boundary segregation in the W-Ni binary alloy and W-Ni-Fe, W-Ni-Ti, W-Ni-Co, W-Ni-Cr, W-Ni-Zr and W-Ni-Nb ternary alloys. The thermodynamic modeling results have been experimentally validated for selected systems. Furthermore, multiscale modeling has been conducted at continuum, atomistic and quantum-mechanical levels to link grain boundary segregation with embrittlement. In summary, this 3-year project has successfully developed a theoretical framework in combination with a multiscale modeling strategy for predicting grain boundary segregation and embrittlement in W based alloys.

  8. UPDATE ON THE STATUS OF ODS ALLOYS FOR FOSSIL ENERGY APPLICATIONS I.G. Wright and B.A. Pint

    E-Print Network [OSTI]

    Pennycook, Steve

    , and resulting microstructures and mechanical properties of joining methods available for use with ODS alloys electricity or producing syngas or other fuels from coal. The ferritic ODS-FeCrAl alloys possess creep unusual properties as well as modes of behavior that are different from conventional, wrought, high

  9. Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys and Alexander A. Balandin

    E-Print Network [OSTI]

    Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys Weili Liua and Alexander A. Balandin have investigated theoretically the thermoelectric effects in wurtzite GaN crystals and AlxGa1-xN-based alloys may have some potential as thermoelectric materials at high temperature. It was found

  10. An ultrahigh vacuum facility for the co-deposition of amorphous transition metal alloy thin films 

    E-Print Network [OSTI]

    Nicoli, Victor Michael

    1984-01-01

    into the superconducting and electron transport properties of amorphous transition metal (TM) alloys is restricted primarily by the availability of high purity samples over a wide range of alloy concentrations. The goals of this thesis are to design components of..., and to assemble an ultrahigh vacuum (UHV) facility for the co-deposition of binary and ternary TN alloy metallic glasses which is also capable of in-situ characteriza- tion of a wide range of their properties in temperatures which vary from 1. 5 K to 300 K...

  11. Of fishes and birthdays: Efficient estimation of polymer configurational entropies

    E-Print Network [OSTI]

    Nemenman, Ilya; Strauss, Charlie E

    2015-01-01

    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.

  12. Entropy production for mechanically or chemically driven biomolecules

    E-Print Network [OSTI]

    Tim Schmiedl; Thomas Speck; Udo Seifert

    2006-01-27

    Entropy production along a single stochastic trajectory of a biomolecule is discussed for two different sources of non-equilibrium. For a molecule manipulated mechanically by an AFM or an optical tweezer, entropy production (or annihilation) occurs in the molecular conformation proper or in the surrounding medium. Within a Langevin dynamics, a unique identification of these two contributions is possible. The total entropy change obeys an integral fluctuation theorem and a class of further exact relations, which we prove for arbitrarily coupled slow degrees of freedom including hydrodynamic interactions. These theoretical results can therefore also be applied to driven colloidal systems. For transitions between different internal conformations of a biomolecule involving unbalanced chemical reactions, we provide a thermodynamically consistent formulation and identify again the two sources of entropy production, which obey similar exact relations. We clarify the particular role degenerate states have in such a description.

  13. ENTROPY-ENERGY BALANCE IN NOISY QUANTUM COMPUTERS

    E-Print Network [OSTI]

    Raginsky, Maxim

    . The atoms are pumped to the level |2 , and then decay nonradiatively to |1 . This results in a relatively will address these two issues using entropy-energy arguments,2 a standard technique in statistical physics. Due

  14. Counterfactuals, dispositions, and conscious experience : essays on entropy

    E-Print Network [OSTI]

    Elga, Adam Newman, 1974-

    2001-01-01

    Chapter 1 of this thesis concerns counterfactual conditionals. David Lewis has offered a natural and influential analysis of counterfactuals. But the analysis fails to take into account the asymmetry of entropy, and comes ...

  15. The rate of entropy increase at the edge of chaos

    E-Print Network [OSTI]

    V. Latora; M. Baranger; A. Rapisarda; C. Tsallis

    2000-07-07

    Under certain conditions, the rate of increase of the statistical entropy of a simple, fully chaotic, conservative system is known to be given by a single number, characteristic of this system, the Kolmogorov-Sinai entropy rate. This connection is here generalized to a simple dissipative system, the logistic map, and especially to the chaos threshold of the latter, the edge of chaos. It is found that, in the edge-of-chaos case, the usual Boltzmann-Gibbs-Shannon entropy is not appropriate. Instead, the non-extensive entropy $S_q\\equiv \\frac{1-\\sum_{i=1}^W p_i^q}{q-1}$, must be used. The latter contains a parameter q, the entropic index which must be given a special value $q^*\

  16. Is Holographic Entropy and Gravity the result of Quantum Mechanics?

    E-Print Network [OSTI]

    Joakim Munkhammar

    2010-03-09

    In this paper we suggest a connection between quantum mechanics and Verlinde's recently proposed entropic force theory for the laws of Newton. We propose an entropy based on the quantum mechanical probability density distribution. With the assumption that the holographic principle holds we propose that our suggested quantum entropy generalizes the Bekenstein entropy used by Verlinde in his approach. Based on this assumption we suggest that Verlinde's entropic theory of gravity has a quantum mechanical origin. We establish a reformulation of the Newtonian potential for gravity based on this quantum mechanical entropy. We also discuss the notion of observation and the correspondence to classical physics. Finally we give a discussion, a number of open problems and some concluding remarks.

  17. Entropy-energy balance in noisy quantum computers

    E-Print Network [OSTI]

    Maxim Raginsky

    2002-09-26

    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.

  18. Aqueous recovery of actinides from aluminum alloys

    SciTech Connect (OSTI)

    Gray, J.H.; Chostner, D.F.; Gray, L.W.

    1989-01-01

    Early in the 1980's, a joint Rocky Flats/Savannah River program was established to recover actinides from scraps and residues generated during Rocky Flats purification operations. The initial program involved pyrochemical treatment of Molten Salt Extraction (MSE) chloride salts and Electrorefining (ER) anode heel metal to form aluminum alloys suitable for aqueous processing at Savannah River. Recently Rocky Flats has expressed interest in expanding the aluminum alloy program to include treatment of chloride salt residues from a modified Molten Salt Extraction process and from the Electrorefining purification operations. Samples of the current aluminum alloy buttons were prepared at Rocky Flats and sent to Savannah River Laboratory for flowsheet development and characterization of the alloys. A summary of the scrub alloy-anode heel alloy program will be presented along with recent results from aqueous dissolution studies of the new aluminum alloys. 2 figs., 4 tabs.

  19. Entropy evolution in warm inflation from a 5D vacuum

    E-Print Network [OSTI]

    Jesus Martin Romero; Mauricio Bellini

    2009-12-15

    Using some ideas of Modern Kaluza-Klein theory, we examine the evolution of entropy on a 4D Friedmann-Robertson-Walker (FRW) brane from a 5D vacuum state, which is defined on a 5D background Riemann-flat metric. We found that entropy production is sufficiently important during inflation: $S > 10^{90}$, for all the initial values of temperature $T_0 < T_{GU}$.

  20. Numerical estimation of the relative entropy of entanglement

    SciTech Connect (OSTI)

    Zinchenko, Yuriy; Friedland, Shmuel; Gour, Gilad

    2010-11-15

    We propose a practical algorithm for the calculation of the relative entropy of entanglement (REE), defined as the minimum relative entropy between a state and the set of states with positive partial transpose. Our algorithm is based on a practical semidefinite cutting plane approach. In low dimensions the implementation of the algorithm in matlab provides an estimation for the REE with an absolute error smaller than 10{sup -3}.

  1. Power Law Corrections to BTZ Black Hole Entropy

    E-Print Network [OSTI]

    Dharm Veer Singh

    2014-11-14

    We study the quantum scalar field in the background of BTZ black hole and evaluate the entanglement entropy of the non-vacuum states. The entropy is proportional to the area of event horizon for the ground state, but the area law is violated in the case of non-vacuum states (first excited state and mixed states) and the corrections scale as power law.

  2. Entropy production at freeze-out from dissipative fluids

    E-Print Network [OSTI]

    E. Molnar

    2007-09-17

    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.

  3. Tolman mass, generalized surface gravity, and entropy bounds

    E-Print Network [OSTI]

    Abreu, Gabriel

    2010-01-01

    In any static spacetime the quasi-local 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 quasi-local entropy that are very similar in spirit to the holographic bound, and closely related to entanglement entropy.

  4. High Temperature coatings based on {beta}-NiAI

    SciTech Connect (OSTI)

    Severs, Kevin

    2012-07-10

    High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

  5. Performance of aluminide coatings applied on alloy CF8C plus at 800 C

    SciTech Connect (OSTI)

    Kumar, Deepak [ORNL] [ORNL; Dryepondt, Sebastien N [ORNL] [ORNL; Shyam, Amit [ORNL] [ORNL; Haynes, James A [ORNL] [ORNL; Pint, Bruce A [ORNL] [ORNL; Armstrong, Beth L [ORNL] [ORNL; Lara-Curzio, Edgar [ORNL] [ORNL

    2011-01-01

    The cost effective, austenitic stainless steel CF8C plus is an attractive alloy for massive cast structures such as steam turbine casings. The microstructure stability and creep strength of this alloy are better than commercial high-performance heat-resistant steels such as NF709 and Super 304H, and are comparable to the Ni-based superalloy Inconel 617. The oxidation resistance of the alloy in atmosphere rich in water vapor is however insufficient at T>800 C, and the use of diffusion aluminide coatings is considered for potential high temperature applications. The thermal stability and protectiveness of coatings applied on the CF8C plus substrate by pack cementation and slurry process were investigated in air + 10% H2O environment at 800 C. Further, the coating effect on the fatigue life of the alloy was assessed via low-cycle-fatigue experiments.

  6. Process for the electrodeposition of low stress nickel-manganese alloys

    DOE Patents [OSTI]

    Kelly, James John; Goods, Steven Howard; Yang, Nancy Yuan-Chi; Cadden, Charles Henry

    2005-06-07

    A process for electrodepositing a low stress nickel-manganese multilayer alloy on an electrically conductive substrate is provided. The process includes the steps of immersing the substrate in an electrodeposition solution containing a nickel salt and a manganese salt and repeatedly passing an electric current through an immersed surface of the substrate. The electric current is alternately pulsed for predetermined durations between a first electrical current that is effective to electrodeposit nickel and a second electrical current that is effective to electrodeposit nickel and manganese. A multilayered alloy having adjacent layers of nickel and a nickel-manganese alloy on the immersed surface of the substrate is thereby produced. The resulting multilayered alloy exhibits low internal stress, high strength and ductility, and high strength retention upon exposure to heat.

  7. Energy, entropy and the Ricci flow

    E-Print Network [OSTI]

    Joseph Samuel; Sutirtha Roy Chowdhury

    2007-12-18

    The Ricci flow is a heat equation for metrics, which has recently been used to study the topology of closed three manifolds. In this paper we apply Ricci flow techniques to general relativity. We view a three dimensional asymptotically flat Riemannian metric as a time symmetric initial data set for Einstein's equations. We study the evolution of the area A and Hawking mass M of a two dimensional closed surface under the Ricci flow. The physical relevance of our study derives from the fact that, in general relativity the area of apparent horizons is related to black hole entropy and the Hawking mass of an asymptotic round 2-sphere is the ADM energy.We begin by considering the special case of spherical symmetry to develop a physical feel for the geometric quantities involved. We then consider a general asymptotically flat Riemannian metric and derive an inequality which relates the evolution of the area of a closed surface S to its Hawking mass. We suggest that there may be a maximum principle which governs the long term existence of the asymptotically flat Ricci flow.

  8. Maximum entropy analysis of cosmic ray composition

    E-Print Network [OSTI]

    Nosek, Dalibor; Vícha, Jakub; Trávní?ek, Petr; Nosková, Jana

    2016-01-01

    We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the sup...

  9. Maximum Entropy Analysis of the Spectral Functions in Lattice QCD

    E-Print Network [OSTI]

    M. Asakawa; T. Hatsuda; Y. Nakahara

    2001-02-26

    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.

  10. Eutectic structures in friction spot welding joint of aluminum alloy to copper

    SciTech Connect (OSTI)

    Shen, Junjun, E-mail: junjun.shen@hzg.de; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; Santos, Jorge F. dos [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Mechanics, Solid-State Joining Processes, Max-Planck-Str. 1, 21502 Geesthacht (Germany)

    2014-05-12

    A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl{sub 2} eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting.

  11. High-Precision Thermodynamics and Hagedorn Density of States

    E-Print Network [OSTI]

    Harvey B. Meyer

    2009-05-26

    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.

  12. A REVIEW OF THE OXIDATION BEHAVIOR OF STRUCTURAL ALLOYS IN STEAM

    SciTech Connect (OSTI)

    Wright, Ian G; Dooley, Barry

    2010-01-01

    The focus of this review is the state of knowledge of the oxidation behavior in steam of alloys with potential for use as pressure parts in steam boilers. Growth of steam-side oxides has implications for scale exfoliation, tube blockage and overheating, and turbine erosion. Mitigation of such problems requires mechanistic understanding of the influences of alloy composition and microstructure as well as time, temperature, and boiler operating parameters on the evolution of specific scale structures. The oxidation behavior in steam of three classes of alloys is addressed: ferritic steels (particularly the 9-12 wt% Cr alloys), austenitic steels, and high-temperature nickel-based alloys. Understanding the interplay among compositional and microstructural requirements for strengthening and oxidation resistance, and their influence on the rate and mode of scale evolution is key to the most effective application of these alloy classes. Underlying these interests is the apparently different mode of oxide growth in steam than in air, especially contributions from inward transport of oxidant species. The particular species involved and their roles in the oxidation process are expected to exert a large influence on the oxide morphologies developed, while the fate of any hydrogen released in the alloy is a further topic of particular interest.

  13. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOE Patents [OSTI]

    Lin, Xianghong (Pasadena, CA); Peker, Atakan (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    1997-01-01

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM.sub.1-x Ti.sub.x).sub.a Cu.sub.b (Ni.sub.1-y Co.sub.y).sub.c wherein x is from 0.1 to 0.3, y.cndot.c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b.

  14. Tailoring Fe-Base Alloys for Intermediate Temperature SOFC Interconnect Application

    SciTech Connect (OSTI)

    J.H. Zhu; M.P. Brady; H.U. Anderson

    2007-12-31

    This report summarized the research efforts and major conclusions for our SECA Phase I and II project focused on Cr-free or low Cr Fe-Ni based alloy development for intermediate temperature solid oxide fuel cell (SOFC) interconnect application. Electrical conductivity measurement on bulk (Fe,Ni){sub 3}O{sub 4} coupons indicated that this spinel phase possessed a higher electrical conductivity than Cr{sub 1.5}Mn{sub 1.5}O{sub 4} spinel and Cr{sub 2}O{sub 3}, which was consistent with the low area specific resistance (ASR) of the oxide scale formed on these Fe-Ni based alloys. For Cr-free Fe-Ni binary alloys, although the increase in Ni content in the alloys improved the oxidation resistance, and the Fe-Ni binary alloys exhibited adequate CTE and oxide scale ASR, their oxidation resistance needs to be further improved. Systematic alloy design efforts have led to the identification of one low-Cr (6wt.%) Fe-Ni-Co based alloy which formed a protective, electrically-conductive Cr{sub 2}O{sub 3} inner layer underneath a Cr-free, highly conductive spinel outer layer. This low-Cr, Fe-Ni-Co alloy has demonstrated a good CTE match with other cell components; high oxidation resistance comparable to that of Crofer; low oxide scale ASR with the formation of electrically-insulating phases in the oxide scale; no scale spallation during thermal cycling; adequate compatibility with cathode materials; and comparable mechanical properties with Crofer. The existence of the Cr-free (Fe,Co,Ni){sub 3}O{sub 4} outer layer effectively reduced the Cr evaporation and in transpiration testing resulted in a 6-fold decrease in Cr evaporation as compared to a state-of-the-art ferritic interconnect alloy. In-cell testing using an anode supported cell with a configuration of Alloy/Pt/LSM/YSZ/Ni+YSZ indicates that the formation of the Cr-free spinel layer via thermal oxidation was effective in blocking the Cr migration and thus improving the cell performance stability. Electroplating of the Fe-Ni-Co alloys as precursor to synthesize a protective spinel layer on commercial ferritic steels has been initiated to facilitate the utilization of the Cr-free spinel as a surface seal to block Cr evaporation. It is suggested that low-cost Fe-Ni-Co alloy coating on commercial ferritic steels might be the best approach to completely eliminate the Cr poisoning problem in SOFC stacks, while maintaining the relatively low overall cost of the interconnect component.

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

    SciTech Connect (OSTI)

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

    2011-01-15

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

  16. Effect of Alloying Element on the Structure of Cu-Zn Alloy

    Office of Scientific and Technical Information (OSTI)

    mold casting of copper-base alloys, including grain refinement as part of developing new lead-free copper alloys for plumbing applications, is being carried out at Materials...

  17. Progress in ODS Alloys: A Synopsis of a 2010 Workshop on Fe- Based ODS Alloys

    SciTech Connect (OSTI)

    Kad, Bimal; Dryepondt, Sebastien N; Jones, Andy R.; Vito, Cedro III; Tatlock, Gordon J; Pint, Bruce A; Tortorelli, Peter F; Rawls, Patricia A.

    2012-01-01

    In Fall 2010, a workshop on the role and future of Fe-based Oxide Dispersion Strengthened (ODS) alloys gathered together ODS alloy suppliers, potential industrial end-users, and technical experts in relevant areas. Presentations and discussions focused on the current state of development of these alloys, their availability from commercial suppliers, past major evaluations of ODS alloy components in fossil and nuclear energy applications, and the technical and economic issues attendant to commercial use of ODS alloys. Significant progress has been achieved in joining ODS alloys, with creep resistant joints successfully made by inertia welding, friction stir welding and plasma-assisted pulse diffusion bonding, and in improving models for the prediction of lifetime components. New powder and alloy fabrication methods to lower cost or improve endproduct properties were also described. The final open discussion centered on challenges and pathways for further development and large-scale use of ODS alloys.

  18. A STUDY OF PRECIPITATION IN INTERSTITIAL ALLOYS. I. PRECIPITATION SEQUENCE IN Ta-C ALLOYS

    E-Print Network [OSTI]

    Dahmen, U.

    2010-01-01

    Acta Meta11urgica A STUDY OF PRECIPITATION IN INTERSTITIALALLOYS. I. PRECIPITATION SEQUENCE IN Ta-C ALLOYS U. Dahmen,ENG-48 y A Study of Precipitation in Interstitial Alloys. I.

  19. Novel pre-alloyed powder processing of modified alnico 8: Correlation of microstructure and magnetic properties

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

    Anderson, I. E.; Kassen, A. G.; White, E. M. H.; Zhou, L.; Tang, W.; Palasyuk, A.; Dennis, K. W.; McCallum, R. W.; Kramer, M. J.

    2015-04-13

    Progress is reviewed on development of an improved near-final bulk magnet fabrication process for alnico 8, as a non-rare earth permanent magnet with promise for sufficient energy density and coercivity for electric drive motors. This study showed that alnico bulk magnets in near-final shape can be made by simple compression molding from spherical high purity gas atomized pre-alloyed powder. Dwell time at peak sintering temperature (1250°C) greatly affected grain size of the resulting magnet alloys. This microstructure transformation was demonstrated to be useful for gaining partially aligned magnetic properties and boosting energy product. While a route to increased coercivity wasmore »not identified by these experiments, manufacturability of bulk alnico magnet alloys in near-final shapes was demonstrated, permitting further processing and alloy modification experiments that can target higher coercivity and better control of grain anisotropy during grain growth.« less

  20. Oxidation of zirconium alloys in 2.5 kPa water vapor for tritium readiness.

    SciTech Connect (OSTI)

    Mills, Bernice E.

    2007-11-01

    A more reactive liner material is needed for use as liner and cruciform material in tritium producing burnable absorber rods (TPBAR) in commercial light water nuclear reactors (CLWR). The function of these components is to convert any water that is released from the Li-6 enriched lithium aluminate breeder material to oxide and hydrogen that can be gettered, thus minimizing the permeation of tritium into the reactor coolant. Fourteen zirconium alloys were exposed to 2.5 kPa water vapor in a helium stream at 300 C over a period of up to 35 days. Experimental alloys with aluminum, yttrium, vanadium, titanium, and scandium, some of which also included ternaries with nickel, were included along with a high nitrogen impurity alloy and the commercial alloy Zircaloy-2. They displayed a reactivity range of almost 500, with Zircaloy-2 being the least reactive.

  1. Chemical Potential in the First Law for Holographic Entanglement Entropy

    E-Print Network [OSTI]

    David Kastor; Sourya Ray; Jennie Traschen

    2014-09-16

    Entanglement entropy in conformal field theories is known to satisfy a first law. For spherical entangling surfaces, this has been shown to follow via the AdS/CFT correspondence and the holographic prescription for entanglement entropy from the bulk first law for Killing horizons. The bulk first law can be extended to include variations in the cosmological constant $\\Lambda$, which we established in earlier work. Here we show that this implies an extension of the boundary first law to include varying the number of degrees of freedom of the boundary CFT. The thermodynamic potential conjugate to $\\Lambda$ in the bulk is called the thermodynamic volume and has a simple geometric formula. In the boundary first law it plays the role of a chemical potential. For the bulk minimal surface $\\Sigma$ corresponding to a boundary sphere, the thermodynamic volume is found to be proportional to the area of $\\Sigma$, in agreement with the variation of the known result for entanglement entropy of spheres. The dependence of the CFT chemical potential on the entanglement entropy and number of degrees of freedom is similar to how the thermodynamic chemical potential of an ideal gas depends on entropy and particle number.

  2. Molybdenum disilicide alloy matrix composite

    DOE Patents [OSTI]

    Petrovic, John J. (Los Alamos, NM); Honnell, Richard E. (Los Alamos, NM); Gibbs, W. Scott (Los Alamos, NM)

    1990-01-01

    Compositions of matter consisting of matrix matrials having silicon carbide dispersed throughout them and methods of making the compositions. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms.

  3. Radiation Tolerance of Neutron-Irradiated Model Fe-Cr-Al Alloys

    SciTech Connect (OSTI)

    Field, Kevin G; Hu, Xunxiang; Littrell, Ken; Yamamoto, Yukinori; Snead, Lance Lewis

    2015-01-01

    The Fe Cr Al alloy system has the potential to form an important class of enhanced accident-tolerant cladding materials in the nuclear power industry owing to the alloy system's higher oxidation resistance in high-temperature steam environments compared with traditional zirconium-based alloys. However, radiation tolerance of Fe Cr Al alloys has not been fully established. In this study, a series of Fe Cr Al alloys with 10 18 wt % Cr and 2.9 4.9 wt % Al were neutron irradiated at 382 C to 1.8 dpa to investigate the irradiation-induced microstructural and mechanical property evolution as a function of alloy composition. Dislocation loops with Burgers vector of a/2 111 and a 100 were detected and quantified. Results indicate precipitation of Cr-rich is primarily dependent on the bulk chromium composition. Mechanical testing of sub-size-irradiated tensile specimens indicates the hardening response seen after irradiation is dependent on the bulk chromium composition. A structure property relationship was developed; it indicated that the change in yield strength after irradiation is caused by the formation of these radiation-induced defects and is dominated by the large number density of Cr-rich precipitates at sufficiently high chromium contents after irradiation.

  4. Erosion-Corrosion of Iron and Nickel Alloys at Elevated Temperature in a Combustion Gas Environment

    SciTech Connect (OSTI)

    Tylczak, Joseph

    2014-05-02

    This paper reports on the results of a study that compares the erosion-corrosion behavior of a variety of alloys (Fe- 2¼Cr 1Mo, 304 SS, 310 SS, Incoloy 800, Haynes 230 and a Fe3Al) in a combustion environment. Advanced coal combustion environments, with higher temperatures, are driving re-examination of traditional and examination of new alloys in these hostile environments. In order to simulate conditions in advanced coal combustion boilers, a special erosion apparatus was used to allow for impingement of particles under a low abrasive flux in a gaseous environment comprised of 20 % CO2, 0.05 % HCl, 77 % N2, 3 % O2, and 0.1 % SO2. Tests were conducted at room temperature and 700 °C with ~ 270 ?m silica, using an impact velocity of 20 m/s in both air and the simulated combustion gas environment. The erosion-corrosion behavior was characterized by gravimetric measurements and by examination of the degraded surfaces optically and by scanning electron microscopy (SEM). At room temperature most of the alloys had similar loss rates. Not surprisingly, at 700 °C the lower chrome-iron alloy had a very high loss rate. The nickel alloys tended to have higher loss rates than the high chrome austenitic alloys.

  5. Multifold Seebeck increase in RuO{sub 2} films by quantum-guided lanthanide dilute alloying

    SciTech Connect (OSTI)

    Music, Denis Basse, Felix H.-U.; Schneider, Jochen M.; Han, Liang; Borca-Tasciuc, Theo; Devender; Gengler, Jamie J.; Voevodin, Andrey A.; Ramanath, Ganpati

    2014-02-03

    Ab initio predictions indicating that alloying RuO{sub 2} with La, Eu, or Lu can increase the Seebeck coefficient ? manifold due to quantum confinement effects are validated in sputter-deposited La-alloyed RuO{sub 2} films showing fourfold ? increase. Combinatorial screening reveals that ? enhancement correlates with La-induced lattice distortion, which also decreases the thermal conductivity twentyfold, conducive for high thermoelectric figures of merit. These insights should facilitate the rational design of high efficiency oxide-based thermoelectrics through quantum-guided alloying.

  6. Amorphous Alloy Membranes Prepared by Melt-Spin methods for Long-Term use in Hydrogen Separation Applications

    SciTech Connect (OSTI)

    Chandra, Dhanesh; Kim, Sang-Mun; Adibhatla, Anasuya; Dolan, Michael; Paglieri, Steve; Flanagan, Ted; Chien, Wen-Ming; Talekar, Anjali; Wermer, Joseph

    2013-02-28

    Amorphous Ni-based alloy membranes show great promise as inexpensive, hydrogenselective membrane materials. In this study, we developed membranes based on nonprecious Ni-Nb-Zr alloys by adjusting the alloying content and using additives. Several studies on crystallization of the amorphous ribbons, in-situ x-ray diffraction, SEM and TEM, hydrogen permeation, hydrogen solubility, hydrogen deuterium exchange, and electrochemical studies were conducted. An important part of the study was to completely eliminate Palladium coatings of the NiNbZr alloys by hydrogen heattreatment. The amorphous alloy (Ni0.6Nb0.4)80Zr20 membrane appears to be the best with high hydrogen permeability and good thermal stability.

  7. $?$-scaling and Information Entropy in Ultra-Relativistic Nucleus-Nucleus Collisions

    E-Print Network [OSTI]

    G. L. Ma; Y. G. Ma; K. Wang; B. H. Sa; W. Q. Shen; H. Z. Huang; X. Z. Cai; H. Y. Zhang; Z. H. Lu; C. Zhong; J. G. Chen; Y. B. Wei; X. F. Zhou

    2003-06-09

    The $\\Delta$-scaling method has been applied to ultra-relativistic p+p, C+C and Pb+Pb collision data simulated using a high energy Monte Carlo package, LUCIAE 3.0. The $\\Delta$-scaling is found to be valid for some physical variables, such as charged particle multiplicity, strange particle multiplicity and number of binary nucleon-nucleon collisions from these simulated nucleus-nucleus collisions over an extended energy ranging from $E_{lab}$ = 20 to 200 A GeV. In addition we derived information entropy from the multiplicity distribution as a function of beam energy for these collisions.

  8. Creep-Fatigue Behavior of Alloy 617 at 850°C

    SciTech Connect (OSTI)

    Carroll, Laura

    2015-05-01

    Creep-fatigue deformation is expected to be a significant contributor to the potential factors that limit the useful life of the Intermediate Heat Exchanger (IHX) in the Very High Temperature Reactor (VHTR) nuclear system.[1] The IHX of a high temperature gas reactor will be subjected to a limited number of transient cycles due to start-up and shut-down operations imparting high local stresses on the component. This cycling introduces a creep-fatigue type of interaction as dwell times occur intermittently. The leading candidate alloy for the IHX is a nickel-base solid solution strengthened alloy, Alloy 617, which must safely operate near the expected reactor outlet temperature of up to 950 °C.[1] This solid solution strengthened nickel-base alloy provides an interesting creep-fatigue deformation case study because it has characteristics of two different alloy systems for which the cyclic behavior has been extensively investigated. Compositionally, it resembles nickel-base superalloys, such as Waspalloy, IN100, and IN718, with the exception of its lower levels of Al. At temperatures above 800 °C, the microstructure of Alloy 617, however, does not contain the ordered ?’ or ?’’ phases. Thus microstructurally, it is more similar to an austenitic stainless steel, such as 316 or 304, or Alloy 800H comprised of a predominantly solid solution strengthened matrix phase with a dispersion of inter- and intragranular carbides. Previous studies of the creep-fatigue behavior of Alloy 617 at 950 °C indicate that the fatigue life is reduced when a constant strain dwell is added at peak tensile strain.[2-5] This results from the combination of faster crack initiation occurring at surface-connected grain boundaries due to oxidation from the air environment along with faster, and intergranular, crack propagation resulting from the linking of extensive interior grain boundary cracking.[3] Saturation, defined as the point at which further increases in the strain-controlled hold time duration no longer decreases the cycle life, has been observed for Alloy 617 at 950 °C at least to the investigated hold times[2,3], as illustrated through a plot of cycles to failure v. hold time in Figure 1. The 950 °C creep-fatigue data set generated by Totemeier and Tian[5] at the 0.3% and 1.0% strain range is consistent in magnitude in terms of the cycles to failure data of that of Carroll et al., however, 0.3% strain range data did not exhibit saturation at hold times of up to 10 min. At 1.0% total strain, saturation in the number of cycles to failure was observed within the investigated peak tensile hold times of up to 10 min[5]. The data of Carroll et al.[2,3] in Figure 1 and Totemeier and Tian[5] is also consistent in magnitude with the data of Rao and coworkers[4] investigated at the 0.6% strain range. It should be noted that saturation in the number of cycles to failure is not present in the data published by Rao and coworkers[4] for tensile hold times of up to 120 min. The latter testing was in a simulated primary-circuit helium gas as opposed to air and a single data point is reported for the longer hold time conditions.

  9. Thorium doped iridium alloy for radioisotope heat sources

    DOE Patents [OSTI]

    Liu, Chain-Tsuan (Oak Ridge, TN); Inouye, Henry (Oak Ridge, TN); Schaffhauser, Anthony C. (Oak Ridge, TN); White, Calvin L. (Powell, TN)

    1981-01-01

    A novel iridium alloy containing 100-500 ppm thorium has enhanced impact properties over undoped iridium and over prior art iridium alloys.

  10. Quantum Alloys Offer Prospects for CO2 Management Technologies...

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

    Quantum Alloys Offer Prospects for CO2 Mgt. Technologies Utilizing and Storing Carbon Dioxide Emissions Quantum Alloys Offer Unique Prospects for CO2 Management Technologies...

  11. Zirconium vanadium chromium alloy

    DOE Patents [OSTI]

    Mendelsohn, M.H.; Gruen, D.M.

    1980-10-14

    A ternary intermetallic compound having the formula Zr(V/sub 1-x/Cr/sub x/)/sub 2/ where x is in the range of 0.01 to 0.90 is capable of reversibly sorbing hydrogen at temperatures ranging from room temperature to 200/sup 0/C, at pressures down to 10/sup -6/ torr. The compound is suitable for use as a hydrogen getter in low pressure, high temperature applications such as magnetic confinement fusion devices.

  12. Neutron Absorbing Alloys

    DOE Patents [OSTI]

    Zhong, Yuanzhen (Wayne, NJ), Parikh, Hemant (Harriman, NY); Smith, Terry E. (Murray, KY)

    2002-05-28

    A process for making homogeneous copolymers of vinylpyrrolidone (VP) and vinyl acetate (VA) which form clear aqueous solutions and have high cloud points. The process involves precharging VP and VA monomers in a predetermined ratio, and then feeding VP and VA at a predetermined rate, the ratio of the components in the initial charge and the feeding rates for the monomer being selected in accordance with the reactivity rates of the monomers towards copolymerization as opposed to homopolymerization.

  13. Higher spin black hole entropy in three dimensions

    E-Print Network [OSTI]

    Alfredo Perez; David Tempo; Ricardo Troncoso

    2013-09-05

    A generic formula for the entropy of three-dimensional black holes endowed with a spin-3 field is found, which depends on the horizon area A and its spin-3 analogue, given by the reparametrization invariant integral of the induced spin-3 field at the spacelike section of the horizon. From this result it can be shown that the absolute value of the spin-3 analogue of the area has to be bounded from above by A/3^(1/2). The entropy formula is constructed by requiring the first law of thermodynamics to be fulfilled in terms of the global charges obtained through the canonical formalism. For the static case, in the weak spin-3 field limit, our expression for the entropy reduces to the result found by Campoleoni, Fredenhagen, Pfenninger and Theisen, which has been recently obtained through a different approach.

  14. Limits on classical communication from quantum entropy power inequalities

    E-Print Network [OSTI]

    Robert Koenig; Graeme Smith

    2012-05-22

    Almost all modern communication systems rely on electromagnetic fields as a means of information transmission, and finding the capacities of these systems is a problem of significant practical importance. The Additive White Gaussian Noise (AWGN) channel is often a good approximate description of such systems, and its capacity is given by a simple formula. However, when quantum effects are important, estimating the capacity becomes difficult: a lower bound is known, but a similar upper bound is missing. We present strong new upper bounds for the classical capacity of quantum additive noise channels, including quantum analogues of the AWGN channel. Our main technical tool is a quantum entropy power inequality that controls the entropy production as two quantum signals combine at a beam splitter. Its proof involves a new connection between entropy production rates and a quantum Fisher information, and uses a quantum diffusion that smooths arbitrary states towards gaussians.

  15. Entropy of isolated horizons from quantum gravity condensates

    E-Print Network [OSTI]

    Oriti, Daniele; Sindoni, Lorenzo

    2015-01-01

    We construct condensate states encoding the continuum spherically symmetric quantum geometry of an isolated horizon in full quantum gravity, i.e. without any classical symmetry reduction, in the group field theory formalism. Tracing over the bulk degrees of freedom, we show how the resulting reduced density matrix manifestly exhibits an holographic behavior. We derive a complete orthonormal basis of eigenstates for the reduced density matrix of the horizon and use it to compute the horizon entanglement entropy. By imposing consistency with the isolated horizon boundary conditions and semi-classical thermodynamical properties, we recover the Bekenstein--Hawking entropy formula for any value of the Immirzi parameter. Our analysis supports the equivalence between the von Neumann (entanglement) entropy interpretation and the Boltzmann (statistical) one.

  16. Time evolution of entanglement entropy from a pulse

    E-Print Network [OSTI]

    Matthew M. Roberts

    2012-04-09

    We calculate the time evolution of the entanglement entropy in a 1+1 CFT with a holographic dual when there is a localized left-moving packet of energy density. We find the gravity result agrees with a field theory result derived from the transformation properties of R\\'enyi entropy. We are able to reproduce behavior which qualitatively agrees with CFT results of entanglement entropy of a system subjected to a local quench. In doing so we construct a finite diffeomorphism which tales three-dimensional anti-de Sitter space in the Poincar\\'e patch to a general solution, generalizing the diffeomorphism that takes the Poincar\\'e patch a BTZ black hole. We briefly discuss the calculation of correlation functions in these backgrounds and give results at large operator dimension.

  17. The entropy of a correlated system of nucleons

    E-Print Network [OSTI]

    Arnau Rios; Artur Polls; Angels Ramos; Herbert Müther

    2006-12-01

    Realistic nucleon-nucleon interaction induce correlations to the nuclear many-body system which lead to a fragmentation of the single-particle strength over a wide range of energies and momenta. We address the question of how this fragmentation affects the thermodynamical properties of nuclear matter. In particular, we show that the entropy can be computed with the help of a spectral function which can be evaluated in terms of the self-energy obtained in the Self-Consistent Green's Function approach. Results for the density and temperature dependences of the entropy per particle for symmetric nuclear matter are presented and compared to the results of lowest order finite temperature Brueckner--Hartree--Fock calculations. The effects of correlations on the calculated entropy are small, if the appropriate quasi-particle approximation is used. The results demonstrate the thermodynamical consistency of the self-consistent T-matrix approximation for the evaluation of the Green's functions.

  18. Holographic Renyi Entropies and Restrictions on Higher Derivative Terms

    E-Print Network [OSTI]

    Georgios Pastras; Dimitrios Manolopoulos

    2015-07-30

    We perform a holographic calculation of the Entanglement R\\'enyi entropy $S_q(\\mu,\\lambda)$, for spherical entangling surfaces in boundary CFT's with Einstein-Gauss-Bonnet-Maxwell holographic gravitational duals. We find that for Gauss-Bonnet couplings $\\lambda$, larger than a specific value, but still allowed by causality, a violation of an inequality that R\\'enyi entropies must obey by definition occurs. This violation is related to the existence of negative entropy black holes and restricts the coefficient of the Gauss-Bonnet coupling in the bulk theory. Furthermore, we discover a distinction in the analytic structure of the analytic continuation of $S_q(\\mu,\\lambda)$, between negative and non-negative $\\lambda$, suggesting the existence of a phase transition.

  19. The effects of colored quark entropy on the bag pressure

    E-Print Network [OSTI]

    Miller, David E

    2004-01-01

    We study the effects of the ground state entropy of colored quarks upon the bag pressure at low temperatures. The vacuum expectation values of the quark and gluon fields are used to express the interactions in QCD ground state in the limit of low temperatures and chemical potentials. Apparently, the inclusion of this entropy in the equation of state provides the hadron constituents with an additional heat which causes a decrease in the effective latent heat inside the hadronic bag and consequently decreases the non-perturbative bag pressure. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag pressure decreases with the temperature. On the other hand, when the colored quark ground state entropy is not considered, the bag pressure as conventionally believed remains constant for finite temperature.

  20. Entropy bounds in terms of the w parameter

    E-Print Network [OSTI]

    Abreu, Gabriel; Visser, Matt

    2011-01-01

    In a pair of recent articles [PRL 105 (2010) 041302 - arXiv:1005.1132; JHEP 1103 (2011) 056 - arXiv:1012.2867] two of the current authors have developed an entropy bound for equilibrium uncollapsed matter using only classical general relativity, basic thermodynamics, and the Unruh effect. An odd feature of that bound, S parameter to be <= 1. When equality holds, the entropy bound saturates at the value expected based on black hole thermodynamics. We also add some clarifying comments regarding the (net) positivity of the chemical potential. Overall, we find that even in the absence of any black hole region, we can nevertheless get arbitrarily close to the Bekenstein entropy.

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

    SciTech Connect (OSTI)

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

    2008-07-24

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

  2. Experimental design to determine the effect of temperature and Mach number on entropy noise

    E-Print Network [OSTI]

    Hake, Mariah I. (Mariah Inez)

    2014-01-01

    The Osney Laboratory sought to create an entropy noise test rig that could determine the relationship between entropy noise and the flow parameters of temperature change and nozzle Mach number. The apparatus simulates ...

  3. Theory: Biological systems organize to maximize entropy production subject to information and biophysicochemical constraints.

    E-Print Network [OSTI]

    Vallino, Joseph J.

    Theory: Biological systems organize to maximize entropy production subject to information: biological systems store information within their metagenome. Therefore, we propose that abiotic systems that biological systems with greater information content will have higher entropy production rates than biological

  4. Entanglement Entropy and Duality in AdS(4)

    E-Print Network [OSTI]

    Ioannis Bakas; Georgios Pastras

    2015-04-30

    Small variations of the entanglement entropy \\delta S and the expectation value of the modular Hamiltonian \\delta E are computed holographically for circular entangling curves in the boundary of AdS(4), using gravitational perturbations with general boundary conditions in spherical coordinates. Agreement with the first law of thermodynamics, \\delta S = \\delta E, requires that the line element of the entangling curve remains constant. In this context, we also find a manifestation of electric-magnetic duality for the entanglement entropy and the corresponding modular Hamiltonian, following from the holographic energy-momentum/Cotton tensor duality.

  5. Quantum-corrected finite entropy of noncommutative acoustic black holes

    E-Print Network [OSTI]

    M. A. Anacleto; F. A. Brito; G. C. Luna; E. Passos; J. Spinelly

    2015-01-31

    In this paper we consider the generalized uncertainty principle in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for 2+1-dimensional noncommutative acoustic black holes. In our results we obtain an area entropy, a correction logarithmic in leading order, a correction term in subleading order proportional to the radiation temperature associated with the noncommutative acoustic black holes and an extra term that depends on a conserved charge. Thus, as in the gravitational case, there is no need to introduce the ultraviolet cut-off and divergences are eliminated.

  6. Quantum-corrected finite entropy of noncommutative acoustic black holes

    E-Print Network [OSTI]

    Anacleto, M A; Luna, G C; Passos, E; Spinelly, J

    2015-01-01

    In this paper we consider the generalized uncertainty principle in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for 2+1-dimensional noncommutative acoustic black holes. In our results we obtain an area entropy, a correction logarithmic in leading order, a correction term in subleading order proportional to the radiation temperature associated with the noncommutative acoustic black holes and an extra term that depends on a conserved charge. Thus, as in the gravitational case, there is no need to introduce the ultraviolet cut-off and divergences are eliminated.

  7. Anomalies, Chern-Simons Terms and Black Hole Entropy

    E-Print Network [OSTI]

    Tatsuo Azeyanagi; R. Loganayagam; Gim Seng Ng

    2015-05-11

    Recent derivations of Cardy-like formulae in higher dimensional field theories have opened up a way of computing, via AdS/CFT, universal contributions to black hole entropy from gravitational Chern-Simons terms. Based on the manifestly covariant formulation of the differential Noether charge for Chern-Simons terms proposed in arXiv:1407.6364, we compute the entropy and asymptotic charges for the rotating charged AdS black holes in higher dimensions at leading order of the fluid/gravity derivative expansion in the Einstein-Maxwell-Chern-Simons system. This gives a result that exactly matches the field theory predictions from Cardy-like formulae.

  8. Potential applications of wrought magnesium alloys for passenger vehicles

    SciTech Connect (OSTI)

    Gaines, L.; Cuenca, R.; Stodolsky, F.; Wu, S.

    1995-12-31

    Vehicle weight reduction is one of the major means available for improving automotive fuel efficiency. Although high-strength steels, aluminum (Al), and polymers are already being used to achieve significant weight reductions, substantial additional weight reductions could be achieved by increased use of magnesium (Mg) and its alloys, which have very low density. Magnesium alloys are currently used in relatively small quantities for auto parts; use is generally limited to die castings, such as housings. The Center for Transportation Research at Argonne National Laboratory has performed a study for the Lightweight Materials Program within DOE`s Office of Transportation Materials to evaluate the suitability of wrought Mg and its alloys to replace steel or aluminum for automotive structural and sheet applications. This study identifies technical and economic barriers to this replacement and suggests R&D areas to enable economical large-volume use. Detailed results of the study will be published at a later date. Magnesium sheet could be used in body nonstructural and semi-structural applications, while extrusions could be used in such structural applications as spaceframes. Currently, Mg sheet has found limited use in the aerospace industry, where costs are not a major concern. The major barrier to greatly increased automotive use is high cost; two technical R&D areas are identified that could enable major reductions in costs. These are novel reduction technology and better hot-forming technology, possibly operating at lower temperatures and involving superplastic behavior.

  9. An Electromotive Force Measurement System for Alloy Fuels

    SciTech Connect (OSTI)

    Changhu Xing; Colby Jensen; Heng Ban; Robert Mariani; J. Rory Kennedy

    2010-11-01

    The development of advanced nuclear fuels requires a better understanding of the transmutation and micro-structural evolution of the materials. Alloy fuels have the advantage of high thermal conductivity and improved characteristics in fuel-cladding chemical reaction. However, information on thermodynamic and thermophysical properties is limited. The objective of this project is to design and build an experimental system to measure the thermodynamic properties of solid materials from which the understanding of their phase change can be determined. The apparatus was used to measure the electromotive force (EMF) of several materials in order to calibrate and test the system. The EMF of chromel was measured from 100°C to 800°C and compared with theoretical values. Additionally, the EMF measurement of Ni-Fe alloy was performed and compared with the Ni-Fe phase diagram. The prototype system is to be modified eventually and used in a radioactive hot-cell in the future.

  10. Method and apparatus for producing high purity silicon

    DOE Patents [OSTI]

    Olson, J.M.

    1983-05-27

    A method for producing high purity silicon includes forming a copper silicide alloy and positioning the alloy within an enclosure. A filament member is also placed within the enclosure opposite the alloy. The enclosure is then filled with a chemical vapor transport gas adapted for transporting silicon. Finally, both the filament member and the alloy are heated to temperatures sufficient to cause the gas to react with silicon at the alloy surface and deposit the reacted silicon on the filament member. In addition, an apparatus for carrying out this method is also disclosed.

  11. Method and apparatus for producing high purity silicon

    DOE Patents [OSTI]

    Olson, Jerry M. (Lakewood, CO)

    1984-01-01

    A method for producing high purity silicon includes forming a copper silie alloy and positioning the alloy within an enclosure. A filament member is also placed within the enclosure opposite the alloy. The enclosure is then filled with a chemical vapor transport gas adapted for transporting silicon. Finally, both the filament member and the alloy are heated to temperatures sufficient to cause the gas to react with silicon at the alloy surface and deposit the reacted silicon on the filament member. In addition, an apparatus for carrying out this method is also disclosed.

  12. Pressure-composition-isotherms of palladium alloys

    SciTech Connect (OSTI)

    Flanagan, T.B.

    1996-11-01

    About one year ago a summary report was submitted covering the previous three years of the contract. This earlier report should be consulted as a useful survey and evaluation of the research carried out by the authors. Because of difficulties during the current contract period arising from the anomalous nature of the melt-spun alloys received from LANL, it is not possible to contribute much beyond that given in last year's summary with regard to the overall picture of the behavior of Pd-rich alloys towards hydrogen and its isotopes. In this contract year deuterium was employed instead of hydrogen and instead of using cycled alloys, the alloys employed for each isotherm measurement were in their virgin condition. Because of the anomalous behavior of the melt-spun alloys, it was not feasible or worthwhile in some cases, e.g., when the alloy behaved anomalously, to carry out all of the originally proposed work. Nonetheless considering these obstacles, some useful data were obtained. For example, the obtaining of deuterium isotherms for the Pd-Rh alloys down to {minus}40 C using internally oxidized melt-spun alloys may prove to be useful.

  13. Alloys of clathrate allotropes for rechargeable batteries

    SciTech Connect (OSTI)

    Chan, Candace K; Miller, Michael A; Chan, Kwai S

    2014-12-09

    The present disclosure is directed at an electrode for a battery wherein the electrode comprises clathrate alloys of silicon, germanium or tin. In method form, the present disclosure is directed at methods of forming clathrate alloys of silicon, germanium or tin which methods lead to the formation of empty cage structures suitable for use as electrodes in rechargeable type batteries.

  14. Energy 32 (2007) 335343 Minimizing the entropy production in a chemical process

    E-Print Network [OSTI]

    Kjelstrup, Signe

    2007-01-01

    Energy 32 (2007) 335­343 Minimizing the entropy production in a chemical process Ranheim, Norway Received 2 November 2005 Abstract We minimize the total entropy production of a process of selected units, which minimized the total entropy production of the process, were found. The most important

  15. Estimates of the Loss of Main-Chain Conformational Entropy of Different Residues on Protein Folding

    E-Print Network [OSTI]

    Pal, Debnath

    Estimates of the Loss of Main-Chain Conformational Entropy of Different Residues on Protein Folding of the main-chain (torsion angles, and ) conformational entropy by taking its side-chain into account. The analysis shows that the main-chain component of the total conformational entropy loss for a residue

  16. Time correlations and the second entropy Angus Gray-Weale and Phil Attard

    E-Print Network [OSTI]

    Attard, Phil

    Time correlations and the second entropy Angus Gray-Weale and Phil Attard School of Chemistry F11 entropies. These entropies are calculated from time correlation functions, as are the transport coefficients to the coupling between variables of opposite time parity in the transport matrix, and show that in general

  17. Zero-Entropy Minimization for Blind Extraction of Bounded Sources (BEBS)

    E-Print Network [OSTI]

    Verleysen, Michel

    Zero-Entropy Minimization for Blind Extraction of Bounded Sources (BEBS) Fr´ed´eric Vrins1 , Deniz, we focus on zero-order Renyi's entropy minimization for the blind extraction of bounded sources (BEBS in the context of BEBS, when the sources have non-convex supports. 1 Introduction Shannon's entropy is a powerful

  18. Entropy production for a class of inverse SRB measures Eugen Mihailescu and Mariusz Urbanski

    E-Print Network [OSTI]

    Urbanski, Mariusz

    Entropy production for a class of inverse SRB measures Eugen Mihailescu and Mariusz Urba´nski Abstract We study the entropy production for inverse SRB measures for a class of hyperbolic folded strictly negative entropy production of the respective inverse SRB measures. Moreover we provide concrete

  19. Vehicle Technologies Office Merit Review 2014: High Speed Joining...

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

    Technologies Office Merit Review 2015: High Strength, Dissimilar Alloy Aluminum Tailor-Welded Blanks ITP Aluminum: Aluminum Industry Roadmap for the Automotive Market (May 1999)...

  20. Development and commercialization status of Fe{sub 3}Al-based intermetallic alloys

    SciTech Connect (OSTI)

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

    1993-06-01

    The Fe{sub 3}Al-based intermetallic alloys offer unique benefits of excellent oxidation and sulfidation resistance, limited by poor room-temperature (RT) ductility and low high-temperature strength. Recent understanding of environmental effects on RT ductility of these alloys has led to progress toward taking commercial advantage of Fe{sub 3}Al-based materials. Cause of low ductility appears to be related to hydrogen formed from reaction with moisture. The environmental effect has been reduced in these intermetallic alloys by two methods. The first deals with producing a more hydrogen-resistant microstructure through thermomechanical processing, and the second dealed with compositional modification. The alloys showing reduced environmental effect have been melted and processed by many different methods. Laboratory and commercial heats have been characterized. Tests have been conducted in both air and controlled environments to quantify environmental effects on these properties. These materials were also tested for aqueous corrosion and resistance to stress corrosion cracking. Oxidation and sulfidation data were generated and effects of minor alloying elements on were also investigated. Several applications have been identified for the newly developed iron aluminides. Commercialization status of these alloys is described.

  1. Oxidation, Creep And Fatigue Properties of Bare and Coated 31V alloy

    SciTech Connect (OSTI)

    Dryepondt, Sebastien N.; Jones, Samuel J.; Zhang, Ying; Maziasz, Philip J.; Pint, Bruce A.

    2014-12-06

    Increasing the efficiency of natural gas reciprocating engines will require materials with better mechanical and corrosion resistance at high temperatures. One solution to increase the lifetime of exhaust valves is to apply an aluminide coating to prevent corrosion assisted fatigue cracking, but the impact of the coating on the valve material mechanical properties needs to be assessed. Creep and high cycle fatigue (HCF) testing were conducted at 816°C on bare and slurry or pack-coated 31V alloy. After annealing according to the 31V standard heat treatment, the coated and bare creep specimens exhibited very similar creep rupture lives. The HCF behavior of the pack-coated alloy was close to the behavior of the bar alloy, but fatigue lifetimes of slurry-coated 31V specimens had higher variability. Aluminide coatings have the potential to improve the valve performance at high temperature, but the coating deposition process needs to be tailored for the substrate standard heat treatment.

  2. Diffusion Welding of Alloys for Molten Salt Service - Status Report

    SciTech Connect (OSTI)

    Denis Clark; Ronald Mizia

    2012-05-01

    The present work is concerned with heat exchanger development for molten salt service, including the proposed molten salt reactor (MSR), a homogeneous reactor in which the fuel is dissolved in a circulating fluid of molten salt. It is an outgrowth of recent work done under the Next Generation Nuclear Plant (NGNP) program; what the two reactor systems have in common is an inherently safe nuclear plant with a high outlet temperature that is useful for process heat as well as more conventional generation The NGNP program was tasked with investigating the application of a new generation of nuclear power plants to a variety of energy needs. One baseline reactor design for this program is a high temperature, gas-cooled reactor (HTGR), which provides many options for energy use. These might include the conventional Rankine cycle (steam turbine) generation of electricity, but also other methods: for example, Brayton cycle (gas turbine) electrical generation, and the direct use of the high temperatures characteristic of HTGR output for process heat in the chemical industry. Such process heat is currently generated by burning fossil fuels, and is a major contributor to the carbon footprint of the chemical and petrochemical industries. The HTGR, based on graphite fuel elements, can produce very high output temperatures; ideally, temperatures of 900 C or even greater, which has significant energy advantages. Such temperatures are, of course, at the frontiers of materials limitations, at the upper end of the performance envelope of the metallic materials for which robust construction codes exist, and within the realm of ceramic materials, the fabrication and joining of which, on the scale of large energy systems, are at an earlier stage of development. A considerable amount of work was done in the diffusion welding of materials of interest for HTGR service with alloys such as 617 and 800H. The MSR output temperature is also materials limited, and is projected at about 700 C. (RR E) A different set of alloys, such as Alloy N and 242, are needed to handle molten salts at this temperature. The diffusion welding development work described here builds on techniques developed during the NGNP work, as applied to these alloys. There is also the matter of dissimilar metal welding, since alloys suitable for salt service are generally not suited for service in gaseous oxidizing environments, and vice versa, and welding is required for the Class I boundaries in these systems, as identified in the relevant ASME codes.

  3. Diffusion Welding of Alloys for Molten Salt Service - Status Report

    SciTech Connect (OSTI)

    Denis Clark; Ronald Mizia; Piyush Sabharwall

    2012-09-01

    The present work is concerned with heat exchanger development for molten salt service, including the proposed molten salt reactor (MSR), a homogeneous reactor in which the fuel is dissolved in a circulating fluid of molten salt. It is an outgrowth of recent work done under the Next Generation Nuclear Plant (NGNP) program; what the two reactor systems have in common is an inherently safe nuclear plant with a high outlet temperature that is useful for process heat as well as more conventional generation The NGNP program was tasked with investigating the application of a new generation of nuclear power plants to a variety of energy needs. One baseline reactor design for this program is a high temperature, gas-cooled reactor (HTGR), which provides many options for energy use. These might include the conventional Rankine cycle (steam turbine) generation of electricity, but also other methods: for example, Brayton cycle (gas turbine) electrical generation, and the direct use of the high temperatures characteristic of HTGR output for process heat in the chemical industry. Such process heat is currently generated by burning fossil fuels, and is a major contributor to the carbon footprint of the chemical and petrochemical industries. The HTGR, based on graphite fuel elements, can produce very high output temperatures; ideally, temperatures of 900 °C or even greater, which has significant energy advantages. Such temperatures are, of course, at the frontiers of materials limitations, at the upper end of the performance envelope of the metallic materials for which robust construction codes exist, and within the realm of ceramic materials, the fabrication and joining of which, on the scale of large energy systems, are at an earlier stage of development. A considerable amount of work was done in the diffusion welding of materials of interest for HTGR service with alloys such as 617 and 800H. The MSR output temperature is also materials limited, and is projected at about 700 °C. (RR E) A different set of alloys, such as Alloy N and 242, are needed to handle molten salts at this temperature. The diffusion welding development work described here builds on techniques developed during the NGNP work, as applied to these alloys. There is also the matter of dissimilar metal welding, since alloys suitable for salt service are generally not suited for service in gaseous oxidizing environments, and vice versa, and welding is required for the Class I boundaries in these systems, as identified in the relevant ASME codes.

  4. Annealing studies of amorphous alloys

    SciTech Connect (OSTI)

    Wiley, J.D.; Perepezko, J.H.; Nordman, J.E.

    1983-04-01

    Amorphous films of the alloys Ni-Nb, Ni-Mo, Mo-Si, and W-Si were sputter deposited on single-crystal semiconductor substrates. One-hour crystallization temperatures of the films were determined to within +-25/sup 0/C by annealing and x-ray diffraction measurements. Interdiffusion between Au or Cu overlayers and the amorphous films were studied by annealing combined with Auger Electron Spectroscopy (AES) profiling, and by Rutherford Backscatter (RBS) analysis. Supplementary measurements used to study structural relaxation and crystallization included resistivity as a function of temperature; DTA and DSC; and electron microscopy.

  5. The -interaction: A study of early stages of phase separation in a Fe-20%Cr-6%Al-0.5%Ti alloy

    E-Print Network [OSTI]

    Cambridge, University of

    of nuclear reactors such as sodium fast reactors (SFR), very-high temperature reactors (VHTR), super critical-cooled fast reactor #12;Material Chemical composition of PM 2000 PM 2000tm is a commercial Fe-base ODS alloy water reactors (SCWR), or other GEN IV nuclear energy systems. oFor such applications, these alloys face

  6. Comments on universal properties of entanglement entropy and bulk reconstruction

    E-Print Network [OSTI]

    Haehl, Felix M

    2015-01-01

    Entanglement entropy of holographic CFTs is expected to play a crucial role in the reconstruction of semiclassical bulk gravity. We consider the entanglement entropy of spherical regions of vacuum, which is known to contain universal contributions. After perturbing the CFT with a relevant scalar operator, also the first order change of this quantity gives a universal term which only depends on a discrete set of basic CFT parameters. We show that in gravity this statement corresponds to the uniqueness of the ghost-free graviton propagator on an AdS background geometry. While the gravitational dynamics in this context contains little information about the structure of the bulk theory, there is a discrete set of dimensionless parameters of the theory which determines the entanglement entropy. We argue that for every (not necessarily holographic) CFT, any reasonable gravity model can be used to compute this particular entanglement entropy. We elucidate how this statement is consistent with AdS/CFT and also give v...

  7. Entropy 2008, 10, 1-x manuscripts ISSN 1099-4300

    E-Print Network [OSTI]

    Dewar, Robert L.

    Paper Relaxed plasma equilibria and entropy-related plasma self-organization principles R. L. Dewar1 (or generated by fusion reactions) deep in the plasma, providing heat which flows towards the much, driven by electric currents in the plasma, gives rise to electromagnetic turbulence. These modes cause

  8. Efficiency of Brownian motors in terms of entropy production rate

    E-Print Network [OSTI]

    Feng, Jianfeng

    OFFPRINT Efficiency of Brownian motors in terms of entropy production rate Min Qian, Xuejuan Zhang) 10014 www.epljournal.org doi: 10.1209/0295-5075/84/10014 Efficiency of Brownian motors in terms a novel approach to the investigation of the efficiency of Brownian motors in the framework

  9. Fuel cell entropy production with ohmic heating and diffusive polarization

    E-Print Network [OSTI]

    Naterer, Greg F.

    transportation. But a key challenge for fuel cells is their overall efficiency. Bossel [1] has reported an alternative entropy based method for systematically improving efficiency of fuel cells. In addition to relatively low efficiencies, a key challenge of automotive fuel cells is quick start-up capabilities in cold

  10. Predicting Customer Behavior using Naive Bayes and Maximum Entropy

    E-Print Network [OSTI]

    Keysers, Daniel

    of returned goods, we additionally generated two binary features for zero and missing values. The remaining Naive Bayes, Maximum Entropy, Neural Networks and Logistic Regression for classification of cus- tomer classifiers won the Data-Mining-Cup in 2004. Combining Logistic Regression, Neural Networks, and Maximum

  11. Entropy production in non-equilibrium fluctuating hydrodynamics

    E-Print Network [OSTI]

    Giacomo Gradenigo; Andrea Puglisi; Alessandro Sarracino

    2012-05-16

    Fluctuating entropy production is studied for a set of linearly coupled complex fields. The general result is applied to non-equilibrium fluctuating hydrodynamic equations for coarse-grained fields (density, temperature and velocity), in the framework of model granular fluids. We find that the average entropy production, obtained from the microscopic stochastic description, can be expressed in terms of macroscopic quantities, in analogy with linear non-equilibrium thermodynamics. We consider the specific cases of driven granular fluids with two different kinds of thermostat and the homogeneous cooling regime. In all cases, the average entropy production turns out to be the product of a thermodynamic force and a current: the former depends on the specific energy injection mechanism, the latter takes always the form of a static correlation between fluctuations of density and temperature time-derivative. Both vanish in the elastic limit. The behavior of the entropy production is studied at different length scales and the qualitative differences arising for the different granular models are discussed.

  12. An entropy measure of uncertainty in vote choiceq

    E-Print Network [OSTI]

    Gill, Jeff

    An entropy measure of uncertainty in vote choiceq Jeff Gillà University of California, Davis, Political Science, One Shield Avenue, Davis, CA 95616, USA Abstract We examine voters' uncertainty in the bill's language, and the bill is disingenuously entitled the ``California Civil Rights Act

  13. Peter Thomas University of Sussex Entropy Excess without Preheating

    E-Print Network [OSTI]

    Thomas, Peter

    , that the entropy of any individual cluster does not tend to a constant within 0.1 R 200 but decreases with radius above the expected relation S / T and seems to tend to a constant oor value. Note, however: 160 3 each of gas and dark-matter Radiative cooling: Sutherland & Dopita, Z = 0:3 (t=t 0 ) Z#12

  14. On the strict positivity of entropy production Vojkan Jaksic1

    E-Print Network [OSTI]

    is sometimes called non-equi- librium steady state (NESS) of the locally perturbed quantum dynamical system (O production observable V = (V ), is well defined for all V Aself. The entropy production of the NESS + V of its NESS is strictly positive. Suppose that the unperturbed system is initially in thermal equilibrium

  15. Entropy considerations in constraining the mSUGRA parameter space

    SciTech Connect (OSTI)

    Nunez, Dario; Sussman, Roberto A.; Zavala, Jesus; Nellen, Lukas; Cabral-Rosetti, Luis G.; Mondragon, Myriam

    2006-09-25

    We explore the use of two criteria to constraint the allowed parameter space in mSUGRA models. Both criteria are based in the calculation of the present density of neutralinos as dark matter in the Universe. The first one is the usual ''abundance'' criterion which is used to calculate the relic density after the ''freeze-out'' era. To compute the relic density we used the numerical public code micrOMEGAs. The second criterion applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas evaluating then the change in the entropy per particle of this gas between the ''freeze-out'' era and present day virialized structures (i.e systems in virial equilibrium). An ''entropy-consistency'' criterion emerges by comparing theoretical and empirical estimates of this entropy. The main objective of our work is to determine for which regions of the parameter space in the mSUGRA model are both criteria consistent with the 2{sigma} bounds according to WMAP for the relic density: 0.0945 < {omega}CDMh2 < 0.1287. As a first result, we found that for A0 = 0, sgn{mu} +, small values of tan{beta} are not favored; only for tan{beta} {approx_equal} 50 are both criteria significantly consistent.

  16. High pressure furnace

    DOE Patents [OSTI]

    Morris, D.E.

    1993-09-14

    A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum)). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 19 figures.

  17. High pressure furnace

    DOE Patents [OSTI]

    Morris, Donald E. (Kensington, CA)

    1993-01-01

    A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

  18. High pressure oxygen furnace

    DOE Patents [OSTI]

    Morris, Donald E. (Kensington, CA)

    1992-01-01

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

  19. High pressure oxygen furnace

    DOE Patents [OSTI]

    Morris, D.E.

    1992-07-14

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized, the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 5 figs.

  20. A possible explanation of the clash for black hole entropy in the extremal limit

    E-Print Network [OSTI]

    Ru-Keng Su; Bin Wang; P. K. N. Yu; E. C. M. Young

    1997-11-24

    It is shown that the classical entropy of the extremal black hole depends on two different limits procedures. If we first take the extremal limit and then the boundary limit, the entropy is zero; if we do it the other way round, we get the Bekenstein-Hawking entropy. By means of the brick wall model, the quantum entropy of scalar field in the extremal black hole background has been calculated for the above two different limits procedures. A possible explanation which considers the quantum effect for the clash of black hole entropy in the extremal limit is given.