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Irradiation Resistance of High-Entropy Alloys
Science Conference Proceedings (OSTI)
About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Fundamental Understanding of High-Entropy Alloy Formation and their ...
Computational Thermodynamics Aided High-Entropy Alloy Design
Presentation Title, Computational Thermodynamics Aided High-Entropy Alloy Design. Author(s), Fan Zhang, Chuan Zhang, Weisheng Cao, Shuanglin Chen.
Fundamental Understanding of High-Entropy Alloy Formation and ...
Organizer(s), Michael Gao, National Energy Technology Lab Peter K Liaw, University of Tennessee. Scope, Recently, high-entropy alloys (HEAs) have attracted ...
Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy alloys
SciTech Connect
High configurational entropies have been hypothesized to stabilize solid solutions in equiatomic, multi-element alloys which have attracted much attention recently as high-entropy alloys with potentially interesting properties. To evaluate the usefulness of configurational entropy as a predictor of single-phase (solid solution) stability, we prepared five new equiatomic, quinary alloys by replacing individual elements one at a time in a CoCrFeMnNi alloy that was previously shown to be single-phase [1]. An implicit assumption here is that, if any one element is replaced by another, while keeping the total number of elements constant, the configurational entropy of the alloy is unchanged; therefore, the new alloys should also be single-phase. Additionally, the substitute elements that we chose, Ti for Co, Mo or V for Cr, V for Fe, and Cu for Ni, had the same room-temperature crystal structure and comparable size/electronegativity as the elements being replaced to maximize solid solubility consistent with the Hume-Rothery rules. For comparison, the base CoCrFeMnNi alloy was also prepared. After three-day anneals at elevated temperatures, multiple phases were observed in all but the base CoCrFeMnNi alloy suggesting that, by itself, configurational entropy is generally not able to override competing driving forces that also govern phase stability. Thermodynamic analyses were carried out for each of the constituent binaries in the investigated alloys (Co-Cr, Fe-Ni, Mo-Mn, etc,). Experimental results combined with the thermodynamic analyses suggest that, in general, enthalpy and non-configurational entropy have bigger influences on phase stability in equiatomic, multi-component alloys. Only when the alloy microstructure is a single-phase, approximately ideal solid solution does the contribution of configurational entropy to the total Gibbs free energy become dominant. Thus, high configurational entropy provides a way to rationalize, after the fact, why a solid solution forms (if it forms) but it is not a useful a priori predictor of which of the so-called high-entropy alloys will form single-phase solid solutions.
Otto, Frederik [ORNL; Yang, Ying [ORNL; Bei, Hongbin [ORNL; George, Easo P [ORNL
High Entropy Alloys a New Class of Structural Materials: Magnetism ...
Perspectives on Phonons and Electron-Phonon Scattering in High-Temperature Superconductors · Prediction and Design of Materials from Crystal Structures to ...
Phase Separation and Intermetallic Formation in "High-entropy" Alloys
In AlCoCrFeNi HEA, high-temperature neutron diffraction indicates A2-B2 phase ... Shared Research Equipment (ShaRE) and Spallation Neutron Source (SNS) ...
Environmental-temperature Effect on a Ductile High-entropy Alloy ...
Atomic Dynamics and Viscosity in the Liquid ... Measuring Strains In Operando in Alloy-based Anodes for Lithium Ion Batteries Using X-ray Diffraction ... Synchrotron X-ray Diffraction Study of the Plasticity of Bulk Metallic Glass Composites.
High Entropy Alloy Formation
Program Organizers: Michael Gao, National Energy Technology Lab; Peter Liaw, University of Tennessee Tuesday 8:00 AM October 9, 2012. Room: Room 410
Symposium on High Entropy Alloys
Jul 31, 2012 ... M. C Gao, National Energy Technology Laboratory ... from Crackling Noise and Slip Avalanche Statistics of Slowly-Sheared Materials.
Studies on Vibrational Entropy in Alloys Using Inelastic Neutron ...
... were measured for a verity of binary alloys using the triple-axis spectrometers at the High Flux Isotope Reactor (HFIR) at Oak Ridge NAtional Laboratory.
Electronic structure and vibrational entropies of fcc Au-Fe alloys
Phonon density of states (DOS) curves were measured on alloys of face-centered-cubic (fcc) Au-Fe using nuclear resonant inelastic x-ray scattering (NRIXS) and inelastic neutron scattering (INS). The NRIXS and INS results were combined to obtain the total phonon DOS and the partial phonon DOS curves of Au and Fe atoms. The 57Fe partial phonon DOS of the dilute alloy Au0.97 57Fe0.03 shows a localized mode centered 4.3% above the cutoff energy of the phonons in pure Au. The Mannheim model for impurity modes accurately reproduced this partial phonon DOS using the fcc Au phonon DOS with a ratio of host-host to impurity-host force constants of 1.55. First-principles calculations validated the assumption of first-nearest-neighbor forces in the Mannheim model and gave a similar ratio of force constants. The high energy local mode broadens with increasing Fe composition, but this has a small effect on the composition dependence of the vibrational entropy. The main effect on the vibrational entropy of alloying comes from a stiffening of the Au partial phonon DOS with Fe concentration. This stiffening is attributed to two main effects: 1) an increase in electron density in the free-electron-like states, and 2) stronger sd-hybridization. These two effects are comparable in magnitude.
Munoz, Jorge A. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Lucas, Matthew [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Mauger, L [California Institute of Technology, W. M. Keck Laboratory, Pasadena] [California Institute of Technology, W. M. Keck Laboratory, Pasadena; Halevy, I [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Horwath, J [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Semiatin, S L [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Xiao, Yuming [Carnegie Institution of Washington] [Carnegie Institution of Washington; Stone, Matthew B [ORNL] [ORNL; Abernathy, Douglas L [ORNL] [ORNL; Fultz, B. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena
High strength alloys
DOE Patents (OSTI)
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.
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
Symposium on High Entropy Alloys II
Jul 15, 2013 ... M. C. Gao, National Energy Technology Laboratory ... Using the statistics of serrations in the stress strain curves to extract materials properties ...
High Temperature Shape Memory Alloys
Mar 5, 2013 ... Shape Memory Response of NiTiHfPd High Strength and High Hysteresis Shape Memory Alloys: Emre Acar1; Haluk Karaca1; Hirobumi Tobe1; ...
High-Strength Alloys; Precipitation
Mar 1, 2011 ... Precipitation Hardenable Mg-Ca-Al Alloys: J. Jayaraj1; C.L. Mendis1; T. Ohkubo1 ; K. Oh-ishi1; K. Hono1; 1National Institute for Materials ...
Development of High Strength Alloys 945 / 945X for HPHT ...
These alloys are manufactured as rods, mechanical tubes, pump shafts and wires. ... A High-Strength Ni-Cr-Mo Alloy for Severe Oil and Gas Environments.
High-temperature alloys for high-power thermionic systems
DOE Green Energy (OSTI)
The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)
Shin, Kwang S.; Jacobson, D.L.; D'cruz, L.; Luo, Anhua; Chen, Bor-Ling.
Nanocomposite Alloy Design for High Frequency Power Conversion ...
Presentation Title, Nanocomposite Alloy Design for High Frequency Power ... of power electronic components and systems for power conditioning and grid ...
High-Strength Low-Alloy Steels
Table 2 Summary of characteristics and intended uses of HSLA steels described in ASTM specifications...le 485 MPa (70 ksi) High-pressure gas and oil transmission lines A 871 High-strength low-alloy steel with atmospheric corrosion resistance V, Nb, Ti, Cu, Mo, Cr As-rolled plate le 35 mm (1 [MathExpression] in.) in thickness Atmospheric-corrosion resistance four
E-Print Network (OSTI)
thermal stability for power transformer applications. Alloysinduction amorphous alloys in power transformers results in
Rabenberg, L.
Highly Dispersed Alloy Cathode Catalyst for Durability
NLE Websites -- All DOE Office Websites (Extended Search)
calculate: METHODS G rxni G rxni l Alloy - G rxni l Pt Computational chemistry methods help to understand catalytic activity and metal If G < 0 alloy atom easier to...
High Cycle Fatigue of ULTIMET Alloy
curves of this alloy regardless of the testing frequencies and environments. At 20 Hz ... The availability of fatigue data in ULTIMET alloy will provide new commercial .... perchloric, 90 ml distilled water, and 100 ml butylcellosolve was used for ...
Creep Behavior of High Temperature Alloys for Generation IV ...
Presentation Title, Creep Behavior of High Temperature Alloys for Generation IV Nuclear Power Plant Applications. Author(s), Xingshuo Wen, Laura J. Carroll, ...
Environmental Degradation and Protection of High Temperature Alloys
Scope, Nickel-base superalloys and other high temperature alloys have been successfully used in turbine engine propulsion, power generation and many other ...
Fabrication of Amorphous Alloy Surface Composites by High ... - TMS
Jun 1, 2007 ... Fabrication of Amorphous Alloy Surface Composites by High-Energy Electron- Beam Irradiation by K. Lee, S. Lee, and N.J. Kim ...
High Temperature Stainless Steel Alloy with Low Cost Manganese
High Temperature Stainless Steel Alloy with Low Cost Manganese ... ••Power industry components such as boiler tubing and piping, pressure vessels, chemical
Creep Behavior of High Temperature Alloys for Intermediate Heat ...
Presentation Title, Creep Behavior of High Temperature Alloys for Intermediate Heat Exchanger in Next Generation Nuclear Plant. Author(s), Xingshuo Wen, ...
Tungsten-Rhenium Super Alloy Development for Ultra High ...
Presentation Title, Tungsten-Rhenium Super Alloy Development for Ultra High Temperature Space Fission and Fusion Reactors. Author(s), Jonathan Webb, ...
Ductile aluminide alloys for high temperature applications
Alloys are described which contain nickel, aluminum, boron, iron and in some instances manganese, niobium and titanium.
Liu, Chain T. (Oak Ridge, TN); Koch, Carl C. (Oak Ridge, TN)
High strength uranium-tungsten alloys
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.
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)
High strength uranium-tungsten alloy process
Improved Ni.sub.3 Al alloys are provided by inclusion of boron, hafnium or zirconium, and in some species, iron.
Liu, Chain T. (Oak Ridge, TN); Stiegler, James O. (Lenoir City, TN)
High-Entropy Alloys FeCoNiAlxSix with High Saturation ...
The electrical resistivity increases to 79.7 ??.cm at x = 0.3 and then decreases with increasing the Al and Si additions. The compressive yield strength and ...
Ir-based alloys for ultra-high temperature applications ...
Site Map; Printable Version; Share this resource. Send a link to Ir-based alloys for ultra-high temperature applications - Energy Innovation Portalto someone by E-mail
Iron aluminide alloys with improved properties for high temperature applications
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.
McKamey, C.G.; Liu, C.T.
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.
McKamey, Claudette G. (Knoxville, TN); Liu, Chain T. (Oak Ridge, TN)
High pressure/high temperature hydrogen permeability in candidate Stirling engine alloys
Hydrogen permeation tests of eight high-temperature alloys were conducted in 20.7 MPa hydrogen at 923 to 1088 K for assessing suitability in Stirling engine application for heater head and heater head tubing. The iron-nickel-base alloys investigated included N-155, Incoloy 800 (IN 800), A-286, and 19-9DL, and cast alloys CRM-6D, SAF-11, and XF-818. Low carbon alloys Stellite 6B (6BLC), a cobalt-base wrought alloy, was also investigated. 15 refs.
Bhattacharyya, S.; Vesely, E.J. Jr.; Hill, V.L.
Improved high temperature creep resistant austenitic alloy
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.
Maziasz, P.J.; Swindeman, R.W.; Goodwin, G.M.
Aluminum Alloying Effects on Lattice Types, Microstructures, and ...
Conference Tools for 2014 TMS Annual Meeting & Exhibition ... In this report, we first review alloying effects on lattice types and properties of HEAs, finding that Al acts as a strong BCC stabilizer, and its ... Characterization of Laser-deposited CoCrFeNi High Entropy Alloy Coatings ... Contact programming@programmaster
Computational and Experimental Development of Novel High-Temperature Alloys
Development of Novel High-Temperature Alloys Background The need for fossil-fueled power plants to run cleaner and more efficiently leads toward ever-higher operating temperatures and pressures. Gas turbines, which can be fueled by natural gas, synthetic gas (syngas), or a high-hydrogen stream derived from coal, are critical components in this development. High-temperature operation of turbines is generally achieved by using nickel-chrome superalloys with coatings
Quantification of linear entropy for quantum entanglement in He, H- and Ps- ions using highly-correlated Hylleraas functions
The quantum entanglement for the two electrons in three-body atomic systems such as the helium atom, the hydrogen negative ion and the positronium negative ion are investigated by employing highly correlated Hylleraas functions to represent the ground states of such systems. As a measure of the spatial entanglement, the linear entropy of the reduced density matrix is calculated for the ground states. The required four-electron (12-dimensional) integrals are solved analytically such that they are suitable for machine computations. Results are compared with other calculations when available.
Lin, Chien-Hao; Ho, Yew Kam
164 Characteristics of Al0.3CoCrFeNiCx High Entropy Alloys
... of LiMnxFe1-xPO4 Glass and Glass-Ceramics for Lithium Ion Battery .... and Comparing the Inhibition Effect of Chromate, Bromate and Molybdate on the ...
Quantifying the economic and commercial potential of a high strength, low thermal coefficient super-alloy
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 ...
Liew, Heng Lee Henry
Nanotwins in Nanocrystalline Mg Alloys: An Insight from High ...
Characterisation of Nano-scaled Precipitates in a Peak Aged Mg-8Gd-2Dy Alloy ... of Nanostructured AZ91D Magnesium Alloy Under Oil-Lubricated Conditions.
Highly Dispersed Alloy Catalyst for Durability
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.
Vivek S. Murthi (Primary Contact), Elise Izzo, Wu Bi, Sandra Guerrero and Lesia Protsailo
Method of making high strength, tough alloy steel
A high strength, tough alloy steel, particularly suitable for the mining industry, is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other subsitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.
Thomas, Gareth (Berkeley, CA); Rao, Bangaru V. N. (Albany, CA)
Insight into Cluster Strengthening in a Nb-Microalloyed High ...
Contributions of Atom Probe Tomography to the Understanding of Steels · Control of p-n ... Relationships in a Series of Co-Cr-Cu-Fe-Ni-Al High Entropy Alloys.
Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications
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
Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar
High-temperature Hydrogen Permeation in Nickel Alloys
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.
P. Calderoni; M. Ebner; R. Pawelko
Radiation Effects on a High Strength, High Conductivity Copper Alloy
Presentation Title, Radiation Effects on a High Strength, High Conductivity Copper ... of Zircaloy during Low Dose Neutron Irradiation at Nominally 375-440° C.
Band anticrossing effects in highly mismatched semiconductor alloys
The first five chapters of this thesis focus on studies of band anticrossing (BAC) effects in highly electronegativity- mismatched semiconductor alloys. The concept of bandgap bowing has been used to describe the deviation of the alloy bandgap from a linear interpolation. Bowing parameters as large as 2.5 eV (for ZnSTe) and close to zero (for AlGaAs and ZnSSe) have been observed experimentally. Recent advances in thin film deposition techniques have allowed the growth of semiconductor alloys composed of significantly different constituents with ever- improving crystalline quality (e.g., GaAs{sub 1-x}N{sub x} and GaP{sub 1-x}N{sub x} with x {approx}< 0.05). These alloys exhibit many novel and interesting properties including, in particular, a giant bandgap bowing (bowing parameters > 14 eV). A band anticrossing model has been developed to explain these properties. The model shows that the predominant bowing mechanism in these systems is driven by the anticrossing interaction between the localized level associated with the minority component and the band states of the host. In this thesis I discuss my studies of the BAC effects in these highly mismatched semiconductors. It will be shown that the results of the physically intuitive BAC model can be derived from the Hamiltonian of the many-impurity Anderson model. The band restructuring caused by the BAC interaction is responsible for a series of experimental observations such as a large bandgap reduction, an enhancement of the electron effective mass, and a decrease in the pressure coefficient of the fundamental gap energy. Results of further experimental investigations of the optical properties of quantum wells based on these materials will be also presented. It will be shown that the BAC interaction occurs not only between localized states and conduction band states at the Brillouin zone center, but also exists over all of k-space. Finally, taking ZnSTe and ZnSeTe as examples, I show that BAC also occurs between localized states and the valence band states. Soft x-ray fluorescence experiments provide direct evidence of the BAC interaction in these systems. In the final chapter of the thesis, I describe and summarize my studies of optical properties of wurtzite InN and related alloys. Early studies performed on InN films grown by sputtering techniques suggested a direct bandgap of {approx}1.9 eV for this semiconductor. Very recently, high-quality InN films with much higher mobility have become available by using the molecular beam epitaxy growth method. Optical experiments carried out on these samples reveal a narrow bandgap for InN of 0.77 eV, much lower than the previously accepted value. Optical properties of InGaN and InAlN ternaries on the In rich side have also been characterized and are found to be consistent with the narrow bandgap of InN. The bandgap bowing parameters in these alloys were determined. In the context of these findings, the bandgap energies of InGaN and InAlN were found to cover a wide spectral range from the infrared for InN to the ultraviolet for GaN and deep ultraviolet for AlN. The significance of this work is rooted in many important applications of nitride semiconductors in optoelectronics and solar energy conversion devices.
Wu, Junqiao
Modification of Alloy 706 for High Temperature Steam Turbine Rotor ...
Alloy706 is a gas-turbine disk material. However, since Alloy706 suffers from a solidification defect (freckle defect) due to segregation of Nb, it is difficult to make ...
Alloy Design of 9% Cr Steel for High Efficiency Ultra-Supercritical ...
Presentation Title, Alloy Design of 9% Cr Steel for High Efficiency Ultra- Supercritical Power Plants. Author(s), Fujio Abe. On-Site Speaker (Planned), Fujio Abe.
Processing of High Performance Alloys for A-USC Steam Turbine ...
Fracture Toughness Evaluation of Polymeric Materials for Wind Turbine Blades Using the Spiral Notch Torsion Test · High Performance Alloys for Advanced ...
High strength and density tungsten-uranium alloys
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.
Sheinberg, Haskell (Los Alamos, NM)
(Ni,Pt)Ti High Temperature Shape Memory Alloys
About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Shape Memory Alloys. Presentation Title, Phase Field Modeling of P-Phase ...
Creep Behavior of High Temperature Alloys as Structural Materials ...
Symposium, Materials and Fuels for the Current and Advanced Nuclear Reactors II ... Alloys as Structural Materials in Generation IV Nuclear Power Plant.
PM Alloy 625M for High Strength Corrosion Resistant Applications
Mechanical properties and stress corrosion cracking data of PM 625M are presented ... However, these alloys have shown a tendency to fail by stress corrosion.
High Temperature Degradation of Alloy 718 after Longtime Exposures
Idaho National Engineering Laboratory. Idaho Falls, ID 834152218. Abstract. An isothermal aging study was carried out on alloy 718 for up to 50,000 hours in a.
SCC Initiation in Alloy 600 Heat Affected Zones Exposed to High Temperature Water
Studies have shown that grain boundary chromium carbides improve the stress corrosion cracking (SCC) resistance of nickel based alloys exposed to high temperature, high purity water. However, thermal cycles from welding can significantly alter the microstructure of the base material near the fusion line. In particular, the heat of welding can solutionize grain boundary carbides and produce locally high residual stresses and strains, reducing the SCC resistance of the Alloy 600 type material in the heat affected zone (HAZ). Testing has shown that the SCC growth rate in Alloy 600 heat affected zone samples can be {approx}30x faster than observed in the Alloy 600 base material under identical testing conditions due to fewer intergranular chromium rich carbides and increased plastic strain in the HAZ [1, 2]. Stress corrosion crack initiation tests were conducted on Alloy 600 HAZ samples at 360 C in hydrogenated, deaerated water to determine if these microstructural differences significantly affect the SCC initiation resistance of Alloy 600 heat affected zones compared to the Alloy 600 base material. Alloy 600 to EN82H to Alloy 600 heat-affected-zone (HAZ) specimens where fabricated from an Alloy 600 to Alloy 600 narrow groove weld with EN82H filler metal. The approximate middle third of the specimen gauge region was EN82H such that each specimen had two HAZ regions. Tests were conducted with in-situ monitored smooth tensile specimens under a constant load, and a direct current electric potential drop was used for in-situ detection of SCC. Test results suggest that the SCC initiation resistance of Alloy 600 and its weld metal follows the following order: EN82H > Alloy 600 HAZ > Alloy 600. The high SCC initiation resistance observed to date in Alloy 600 heat affected zones compared to wrought Alloy 600 is unexpected based on the microstructure of HAZ versus wrought material and based on prior SCC growth rate studies. The observed behavior for the HAZ specimens is likely not related to differences in the environment, differences in surface stress/strain between the various specimen regions (weld, HAZ, wrought), differences in surface residual stress, or differences in the microstructure of the various specimen regions (weld, HAZ, wrought). The behavior may be related to differences in the creep behavior of the various weld regions or differences in the surface area of the various materials (weld, HAZ, wrought) exposed to high temperature water.
E Richey; DS Morton; RA Etien; GA Young; RB Bucinell
Phonon Thermodynamics of Binary Fe Alloys
Proceedings Inclusion? Planned: A CD-only volume ... Studies on Vibrational Entropy in Alloys Using Inelastic Neutron Scattering at ORNL · Surface Prefreezing ...
Advanced Alloys for Compact, High-Efficiency, High-Temperature Heat-Exchangers
Oak Ridge National Laboratory (ORNL) has conducted research and development for several years which has been focused on the behavior and performance improvements of sheets and foils of various alloys for compact heat-exchangers (recuperators) for advanced microturbines. The performance and reliability of such thin sections are challenged at 650-750 C by fine grain size causing excessive creep, and by moisture effects greatly enhancing oxidation attack in exhaust gas environments. Standard 347 stainless steel has been used successfully at or below 600 C, but has suffered from both of these kinds of degradation at 650 C and above. Alloys have been identified which can have very good properties for such heat-exchangers, especially with careful control of microstructure during processing, including alloy 625, HR120 and the new AL20-25+Nb. These alloys, and the mechanistic understanding behind their behavior, are also applicable to achieving the better heat-exchanger technology needed for fuel cells or other high-temperature, clean-energy applications.
Maziasz, Philip J [ORNL; Pint, Bruce A [ORNL; Shingledecker, John P [ORNL; Evans, Neal D [ORNL; Yamamoto, Yukinori [ORNL; More, Karren Leslie [ORNL; Lara-Curzio, Edgar [ORNL
Design and Manufacturing Guidelines for High-Strength Components in LWRs--Alloy X-750
Alloy X-750, commonly used in high-strength internal reactor components, occasionally experiences intergranular stress corrosion cracking (IGSCC). EPRI's new design and manufacturing guidelines, specifying parameters that can influence IGSCC resistance, will assist utilities in reducing the probability of in-service failures of alloy X-750 components.
Dynamic compressive behavior of Pr-Nd alloy at high strain rates and temperatures
Based on compressive tests, static on 810 material test system and dynamic on the first compressive loading in split Hopkinson pressure bar (SHPB) tests for Pr-Nd alloy cylinder specimens at high strain rates and temperatures, this study determined a J-C type [G. R. Johnson and W. H. Cook, in Proceedings of Seventh International Symposium on Ballistics (The Hague, The Netherlands, 1983), pp. 541-547] compressive constitutive equation of Pr-Nd alloy. It was recorded by a high speed camera that the Pr-Nd alloy cylinder specimens fractured during the first compressive loading in SHPB tests at high strain rates and temperatures. From high speed camera images, the critical strains of the dynamic shearing instability for Pr-Nd alloy in SHPB tests were determined, which were consistent with that estimated by using Batra and Wei's dynamic shearing instability criterion [R. C. Batra and Z. G. Wei, Int. J. Impact Eng. 34, 448 (2007)] and the determined compressive constitutive equation of Pr-Nd alloy. The transmitted and reflected pulses of SHPB tests for Pr-Nd alloy cylinder specimens computed with the determined compressive constitutive equation of Pr-Nd alloy and Batra and Wei's dynamic shearing instability criterion could be consistent with the experimental data. The fractured Pr-Nd alloy cylinder specimens of compressive tests were investigated by using 3D supper depth digital microscope and scanning electron microscope.
Wang Huanran; Cai Canyuan; Chen Danian [Mechanics and Materials Science Research Center, Ningbo University, Ningbo, Zhejiang 315211 (China); Ma Dongfang [Mechanics and Materials Science Research Center, Ningbo University, Ningbo, Zhejiang 315211 (China); School of Civil Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000 (China)
Copper modified austenitic stainless steel alloys with improved high temperature creep resistance
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.
Swindeman, R.W.; Maziasz, P.J.
Role of Entropy in Protein Thermostability: Folding Kinetics of a Hyperthermophilic Cold Shock Protein at High Temperatures Using 19
and hyperthermophilic cold shock proteins at ambient temperature extend to their temperature depen- dence: the lower The conservation of the temperature dependences of folding and unfolding in this family of small cold shockRole of Entropy in Protein Thermostability: Folding Kinetics of a Hyperthermophilic Cold Shock
Schuler, Ben
Two-phase chromium-niobium alloys exhibiting improved mechanical properties at high temperatures
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.
Liu, Chain T. (Oak Ridge, TN); Takeyama, Masao (Tokyo, JP)
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.
Liu, C.T.; Takeyama, Masao.
Flow Behavior of Three 625-Type Alloys During High Temperature ...
heat exchangers, and piping. The alloy ..... H.H. Ruble and S.L. Semiatin, Metal;s Handbook Ninth Edition (Metals Park, OH: ASM. International, 1988), 261-266.
Deployment of New High Temperature Alloys for Power Generation ...
Abstract Scope, Two Fe-base alloys developed at ORNL, alumina-forming austenitic (AFA) steel and cast austenitic CF8C-Plus, ... Definite: A CD-only volume ...
A High Strength, Oxidation Resistant DS Turbine Airfoil Alloy
Particular thanks go to Dr. Robert E. Allen of EMTL who sustained funding for the development of Rene'142 and led the scale-up and introduction of the alloy ...
HIGH TEMPERATURE BRAZING ALLOY FOR JOINT Fe-Cr-Al MATERIALS AND AUSTENITIC AND FERRITIC STAINLESS STEELS
A new high temperature brazing alloy is described that is particularly suitable for brazing iron-chromiumaluminum alloys. It consists of approximately 20% Cr, 6% Al, 10% Si, and from 1.5 to 5% phosphorus, the balance being iron.
Cost, R.C.
High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerance
9 9 HigH Permeability ternary Palladium alloy membranes witH imProved sulfur and Halide tolerance Description A critical step in the transition to the hydrogen economy is the separation of hydrogen from coal gasification gases (syngas) or methane. This is typically accomplished through membrane separation. Past research has shown that palladium (Pd) alloys possess great potential as robust and economical membranes. However, the search for the optimal binary or ternary alloys is an involved and costly process due to the immense number of alloy variations that could be prepared and tested. Recent modeling work at Georgia Institute of Technology using density functional theory (DFT) identified several promising ternary alloy compositions with improved
Stress corrosion cracking and hydrogen embrittlement of thick section high strength low alloy steel
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 ...
Needham, William Donald
CoNiFe Alloy Powder Synthesis by High Energy Milling
CoNiFe alloy powder was synthesized by high energy milling of mixtures of Co, Ni and Fe powder as a bulk processing method for producing powder. A milling ...
Iron-niobium-aluminum alloy having high-temperature corrosion resistance
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.
Hsu, Huey S.
Candidate alloys for cost-effective, high-efficiency, high-temperature compact/foil heat-exchangers
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.
Evans, Neal D [ORNL; Maziasz, Philip J [ORNL; Shingledecker, John P [ORNL; Pint, Bruce A [ORNL; Yamamoto, Yukinori [ORNL
The factors affecting corrosion resistance both of bare and of clad uranium-base alloys are reviewed and a mechanism proposed for their corrosion behavior. For unclad gamma-phase uranium alloys exposed to a high temperature water corrodent, it is proposed that the corrosion rate is determined primarily by the oxidation of the alloy by water. This behavior is contrary to that of alpha uranium in which the corrosion rate is primarily determined by the formation and subsequent oxidation of a nonadherent hydride layer. In gamma- phase alloys the hydrogen released by the corrosion reaction, rather than forming the thermodynamically stable UH/sub 3/ phase, dissolves (at least in part) in the base metal where it precipitates as a metastable hydride. The amount of hydrogen absorbed by the metal and hence precipitating as the metastable hydride may be markedly reduced by the addition of hydrogen depolarizers such as nickel or platinum to the water or to the metal. Similarly the amount of absorbed hydrogen may be reduced by introducing sinks that preferentially absorb hydrogen. Both alpha uranium and zirconium were shown to be suitable sinks. Precipitated hydride hardens and embrittles the matrix and by its preferential corrosion eventually leads to discontinuous failure. The hydride may be made to precipitate in a less harmful manner by heat treatments which precipitate nucleating and hardening impurities. The mode of the precipitation is shown to be sensitive to stress; in fact, the assumption of elastic stress as contributing to hydride precipitation is considered necessary to explain the distribution of the precipitate during corrosion. In order to apply a gammaphase fuel alloy as a fuel element material, it is necessary primarily to reduce the amount of hydrogen absorbed by the fuel. This can be done by cladding the fuel with a zirconium- base alloy. Under such conditions it has been shown that fuel element lives in excess of 4 years should be obtainable with properly fabricated fuel elements before they are subject to corrosion failure. Optimum fuel element corrosion life can be achieved by decreasing the general corrosion rate, increasing the hydrogen solubility, increasing the hydrogen diffusion rate, and maintaining a proper clad-fuel bond. For uranium-base alloys such as U/sub 3/Si that do not form a hydride during hot water corrosion, use of a Zircaloy clad is unnecessary. Therefore, the development of alternate cladding materials such as Al for corrosion resistant fuel elements is predicted upon the development of uranium- base alloys that do not corrode by a hydride mechanism. In addition to U/sub 3/ both Zr-U alloys and the strained alpha uranium-base alloys do not appear to corrode by a hydride mechanism. (auth)
Burkart, M.W. ed.
Advanced nickel base alloys for high strength, corrosion applications
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.
Flinn, John E. (Idaho Falls, ID)
Pu-Zr alloy for high-temperature foil-type fuel
A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron reflux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.
McCuaig, Franklin D. (LaGrange, IL)
Pu-ZR Alloy high-temperature activation-measurement foil
A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron flux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.
McCuaig, Franklin D. (Westmont, IL)
High-strength, creep-resistant molybdenum alloy and process for producing the same
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 ({approximately}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.
Bianco, Robert; Buckman, Jr. William R.; Geller, Clint B.
High Temperature Corrosion Behavior of Oxidation Resistant Alloys under SOFC Interconnect Dual Exposures
The steady reduction in SOFC operating temperatures has led to increased interest in using metals and alloys to construct the stack interconnects that are exposed simultaneously to a fuel at the anode-side and air at the cathode-side during SOFC operation. Previous work has found that the high temperature oxidation and corrosion behavior of alloys under the dual exposure conditions can be significantly different from that in a single atmosphere exposure. To fully understand the anomalous oxidation and corrosion behavior under the interconnect dual exposure conditions, a number of metals and alloys were investigated under a variety of conditions, including both hydrogen and hydrocarbon fuels. This paper will present details of this work and discuss our current understanding on the anomalous oxidation behavior of metals and alloys observed under the interconnect dual exposure conditions.
Yang, Z Gary; Coffey, Greg W.; Rice, Joseph P.; Singh, Prabhakar; Stevenson, Jeffry W.; Xia, Gordon
Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys
Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepared ribbons. Results show that the amorphous alloys can be exposed to 600 C for 1-hr. without losing the corrosion resistance; however, when the ribbons were exposed at 800 C for 1-hr. their localized corrosion resistance decreased significantly.
Day, S D; Haslam, J J; Farmer, J C; Rebak, R B
Embrittlement and DBTT of High-Burnup PWR Fuel Cladding Alloys | Department
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Embrittlement and DBTT of High-Burnup PWR Fuel Cladding Alloys Embrittlement and DBTT of High-Burnup PWR Fuel Cladding Alloys Embrittlement and DBTT of High-Burnup PWR Fuel Cladding Alloys Structural analyses of high-burnup (HBU) fuel require cladding mechanical properties and failure limits to assess fuel behavior during long-term dry-cask storage and transportation. Pre-storage drying-transfer operations and early stage storage subject cladding to higher temperatures and pressure-induced tensile hoop stresses relative to in-reactor operation and pool storage. Under these conditions, radial hydrides may precipitate during slow cooling and provide an additional embrittlement mechanism as the cladding temperature decreases below the ductile-to-brittle transition temperature (DBTT). Graphic and photographic details of the testing are
Hydrogen induced surface cracking in an 8090 Al-Li alloy during high cycle fatigue
In recent years, there has been an increasing interest in understanding the effects of aggressive or moist environments on the properties of Al-Li alloys. However, most of the existing work has been focused on their stress corrosion cracking resistance. Consequently, only a few reports are available on the environmental fatigue strength of these alloys. Upon exposure to aggressive environments, the fatigue crack propagation resistance can be detrimentally affected. R. Piascik and R. Gangloff found enhanced cyclic crack growth rates in an Al-Li-Cu alloy when a critical water vapor pressure was exceeded. Thermodynamically, at atmospheric pressures, strong interactions between hydrogen and lithium are expected to give rise to stable lithium hydrides. Evidence for the development of hydride phases in Al-Li alloys exposed to hydrogen environments has been reported by various workers. Thus, it is likely that HE via hydride formation can be the relevant mechanisms in Al-Li alloys that have been in contact with hydrogen. Since lithium hydrides are stable up to temperatures of 773 K, previous hydrogen exposure can lead to an irreversible mode of embrittlement. Thus, it was the objective of the present work to investigate the effects of hydrogen during aging on the ensuing high cycle fatigue (HCF) performance of an 8090 Al-Li alloy.
Laffin, C.; Raghunath, C.R.; Lopez, H.F. (Univ. of Wisconsin, Milwaukee, WI (United States). Materials Dept.)
Considerations of Alloy N for Fluoride Salt-Cooled High-Temperature Reactor Applications
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.
Ren, Weiju [ORNL; Muralidharan, Govindarajan [ORNL; Wilson, Dane F [ORNL; Holcomb, David Eugene [ORNL
Response of aluminum and its alloys to exposure in the high flux isotope reactor
Pure aluminum and some aluminum alloys were irradiated to very high neutron fluences in the cooling water at 328 K in the high flux region of HFIR. Displacement levels of 270 dpa and transmutation-produced silicon levels of 7.15 wt % were reached. Damage microstructures consisted of dislocations, cavities, and precipitates which caused substantial strengthening and associated loss in ductility. Formation of cavities and related swelling were considerably reduced by alloying elements and by the presence of fine Mg/sub 2/Si precipitate.
Farrell, K.
Boltzmann Entropy : Probability and Information
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.
C. G. Chakrabarti; Indranil Chakrabarty
Candidate Alloys for Cost-Effective, High-Efficiency, High ... - TMS
Sep 16, 2007... attractive sources for combined heat and power (CHP) cogeneration. ... and suggest that these alloys developed for gas- and micro-turbine ...
Consequences of water injection into high-temperature lithium-lead alloy breeder material
A fusion safety experiment was conducted to determine the consequences of water injection into high-temperature lithium-lead alloy under postulated reactor accident conditions. The temperature and pressure response, fraction of water reacted, quantity of hydrogen produced, and behavior of radioactive species associated with the use of this alloy as a breeder material were determined. The reaction products were identified and the aerosol was characterized for particle size, chemical composition, and deposition rate. The water injection was shown to be self limiting for a blanket module designed to withstand the pressure of the water coolant. Radioactive doses associated with the aerosol release from a high-temperature alloy breeder module were determined to be several orders of magnitude below the dose limit for acute health effects. The results were compared to previous experiments and recommendations were made. 5 refs., 7 figs., 6 tabs.
Jeppson, D.W. (Westinghouse Hanford Co., Richland, WA (USA)); Savatteri, C. (Commission of the European Communities, Ispra (Italy))
Numerical Generation of Entropies
The spurious numerical generation and/or destruction of various types of entropies in models is investigated. It is shown that entropy s? of dry matter tends to be generated if potential temperature is advected by a damping scheme. There is no ...
Joseph Egger
Solidification processing and phase transformations in ordered high temperature alloys. Final report, 30 March 1990-30 September 1992
Useful high temperature alloys generally have microstructures consisting of more than one phase. Multiphase microstructures are necessary to develop acceptable toughness and creep strength in high temperature intermetallic alloy matrices. The optimum microstructures must be developed by a careful selection of processing path that includes both solidification and solid state heat treatment. Research has been conducted on the rapid solidification of selected intermetallic alloys and on the phase transformation paths that occur during cooling, primarily in the Ti-Al-Nb system. This report describes research performed in the Metallurgy Division at NIST under DARPA order 7469 between 1/1/89 and 12/31/92. Various research tasks were completed and the results have been published or have been submitted for publication.... Intermetallics, Ti-Al-Nb Alloys, Phase Diagrams, Phase Transformations, Ti-Al-Ta Alloys, MoSi2 Alloys.
Boettinger, W.J.; Bendersky, L.A.; Kattner, U.R.
High-field superconductivity in some bcc Ti-Mo and Nb-Zr alloys
Zero electrical resistance at unusually high magnetic field strengths has been observed in the bcc alloys Ti-16 a/o (atomic percent) Mo, Nb-12 a/o Zr, and Nb-25 a/o Zr. The maximum highfield zero-resistance current density, Jc, in these ...
R. R. Hake; T. G. Berlincourt; D. H. Leslie
High-power laser and arc welding of thorium-doped iridium alloys
The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.
David, S.A.; Liu, C.T.
Environmental Cracking Resistance of High Nickel Alloys (CRAs
Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well · Evaluation of the Susceptibility to Hydrogen Assisted Cracking in ...
Local entropy generation analysis
Second law analysis techniques have been widely used to evaluate the sources of irreversibility in components and systems of components but the evaluation of local sources of irreversibility in thermal processes has received little attention. While analytical procedures for evaluating local entropy generation have been developed, applications have been limited to fluid flows with analytical solutions for the velocity and temperature fields. The analysis of local entropy generation can be used to evaluate more complicated flows by including entropy generation calculations in a computational fluid dynamics (CFD) code. The research documented in this report consists of incorporating local entropy generation calculations in an existing CFD code and then using the code to evaluate the distribution of thermodynamic losses in two applications: an impinging jet and a magnetic heat pump. 22 refs., 13 figs., 9 tabs.
Drost, M.K.; White, M.D.
Amorphous Alloy Membranes for High Temperature Hydrogen Separations
for High for High Temperature Hydrogen Separations Background Coal and biomass are readily available in the United States and can be mixed for thermal processing to produce hydrogen and power. The produced hydrogen can be sent directly to a fuel cell for highly efficient and environmentally clean power generation. For coal and biomass to become economically viable sources of hydrogen, more efficient production processes need to be developed. To meet this
Processing of Soft Magnetic Alloys in High Magnetic Field
... Magnetic Materials for Use in Energy-efficient Distribution Transformers ... Novel Morphology of Highly Efficient Two-phase Ferrite Cores for Power Systems
Corrosion of Candidate Alloys in High Temperature Supercritical
Materials corrosion in high temperature supercritical CO2 will be an important consideration for this application. The results of corrosion evaluations of a wide ...
Evaluation of High-Temperature Alloys for Helium Gas Turbines
C. 1. Mechanical Property / Status of Metallic Materials Development for Application in Advanced High-Temperature Gas-Cooled Reactor / Material
Wolfgang Jakobeit; Jörn-Peter Pfeifer; Georg Ullrich
High Quality, Dense Thin Films Using Metal/Metal Alloy ...
Berkeley Lab researchers Mike Tucker, Grace Lau, and Craig Jacobson have invented a novel layered structure for preparing a high-operating temperature ...
Characterization of U-7Mo Alloy Microstructure Irradiated to High ...
Abstract Scope, The Reduced Enrichment for Research and Test Reactor ... for use in reactors that currently employ fuels containing highly enriched uranium.
Microstructure Control of Ni Base Alloys with High Volume Fraction ...
hypo-stoichiometric composition of Ni3V, formation of "multi- variant structure ... reasons; one is the high TC (1318 K) at its stoichiometric composition [1, 2], and ...
Copper Casting Alloys
Table 8 Compositions, uses, and characteristics of copper alloy castings...operating at moderate-to-high speeds, as in electric motors and appliances. Alloy C93200 is
Corrosion of Metals and Alloys in High Radiation Fields
This paper rationalizes the impact of high radiation fields on corrosion, hydrogen embrittlement and corrosion fatigue and relates that impact to radiation induced changes in chemical reactivity, hydrogen fugacity, and surface chemistry.
Sindelar, R.L.
Grain growth behavior and high-temperature high-strain-rate tensile ductility of iridium alloy DOP-26
This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the new-process iridium-based DOP-26 alloy used for the Cassini space mission. This alloy was developed at Oak Ridge National Laboratory (ORNL) in the early 1980`s and is currently used by NASA for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. Included within this report are data generated on grain growth in vacuum or low-pressure oxygen environments; a comparison of grain growth in vacuum of the clad vent set cup material with sheet material; effect of grain size, test temperature, and oxygen exposure on high-temperature high-strain-rate tensile ductility; and grain growth in vacuum and high-temperature high-strain-rate tensile ductility of welded DOP-26. The data for the new-process material is compared to available old-process data.
McKamey, C.G.; Gubbi, A.N.; Lin, Y.; Cohron, J.W.; Lee, E.H.; George, E.P.
High-Yield Solvothermal Formation of Magnetic CoPt Alloy Nanowires
One-dimensional (1D) magnetic nanomaterials have attracted much attention recently because of their applications in magnetic recording and spintronics. Nevertheless, it remains a challenge to prepare free-standing magnetic nanowires in high yield. This Communication reports the successful high-yield synthesis of an interesting 1D ferromagnetic CoPt alloy by direct decomposition of platinum acetylacetonate and cobalt carbonyl compound in ethylenediamine solvent through a solvothermal reaction. The CoPt alloy nanowires obtained have a tunable diameter of 10-50 nm and a length along the longitudinal axis of up to several microns, depending on crystallization temperature and reaction time. A unique formation mechanism involving coarsening and ripening under solvothermal conditions was discovered. This research opens new opportunities in synthesizing nanomaterials through low-temperature solvothermal processes.
Zhang, Zongtao [ORNL; Blom, Douglas Allen [ORNL; Gai, Zheng [ORNL; Thompson, James R [ORNL; Shen, Jian [ORNL; Dai, Sheng [ORNL
Quantum Fine-Grained Entropy
Regarding the strange properties of quantum entropy and entanglement, e.g., the negative quantum conditional entropy, we revisited the foundations of quantum entropy, namely, von Neumann entropy, and raised the new method of quantum fine-grained entropy. With the applications in entanglement theory, quantum information processing, and quantum thermodynamics, we demonstrated the capability of quantum fine-grained entropy to resolve some notable confusions and problems, including the measure of entanglement and quantumness, the additivity conjecture of entanglement of formation etc, and the definition of temperature for single quantum system.
Wang, Dong-Sheng
High Temperature Corrosion Resistance of Fe-Ni-Cr Alloys in CO2 ...
Austenitic Steel Oxidation in Steam: Alloy Composition and Surface Modification ... Ni-Base Alloys for Use as Components in Advanced-USC Steam Turbines.
Corrosion of high temperature alloys in solar salt at 400, 500, and 680%C2%B0C.
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.
Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth
This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.
Smith, K.F.; Van Thyne, R.J.
Strees Corrosion Cracking Initiation of Ni-Bassed Alloys in High Temperature Water
The goal of the work is to provide stress corrosion cracking (SCC) initiation data for Alloy 600 that is not compromised by (1) specimens that suffer from stress relaxation, (2) specimens which have an unknown stress state, (3) specimens which are tested at unknown positions electrochemically relative to the Ni/NiO phase transition, and (4) testing which relies on the period of time between specimen inspection intervals to estimate SCC initiation times. The current study was aimed at studying the effects of temperature and coolant hydrogen concentration on SCC initiation in high purity, high temperature water.
E Richey; D Morton
Deterministic Complexity and Entropy
Lempel and Ziv (1976) proposed a computable string production-complexity. In this paper, our emphasis is on providing the rigorous development, where possible, for the theoretical aspects of a more recent and contrasting measure of string complexity. ... Keywords: Formal languages, T-codes, complexity measures, entropy, generative systems, information, prefix codes
Mark R. Titchener; Radu Nicolescu; Ludwig Staiger; Aaron Gulliver; Ulrich Speidel
Computational Thermodynamics of CoNiGa High Temperature Shape Memory Alloys
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 Temperature Shape Memory Alloys (HTSMAs), with possible applications in the aerospace and automotive industries. Although the CoNiGa system shows significant promise for its use as HTSMAs, limited studies are available on them. Hence, a more intensive investigation of these alloys is necessary to understand their phase stability over a wide range of temperature and compositions in order for further development of CoNiGabased HTSMAs and future use of the model in alloy design. This formed the basis of motivation for the present work. In this work, a thermodynamic model of the ternary system is calculated based on the CALPHAD approach, to investigate the thermodynamic properties, phase stability and shape memory properties of these alloys. The CALPHAD approach is a computational method that enables the calculations of thermodynamic properties of systems. This method uses all available experimental and theoretical data in order to calculate the Gibbs energies of the phases in the system. The software used to carry out the calculations is "ThermoCalc," which is a computational software using CALPHAD principles, based on the minimization of Gibbs energy, and is enhanced by a global minimization technique on the system. The stability of the beta phase at high temperatures was enforced accurately by remodeling the CoGa system. The binary CoGa system that makes up the ternary was remodeled, as the beta phase (which is very important as it dominates the central region of the ternary CoNiGa system where the shape memory effect is observed), re-stabilizes as the temperature increases above the liquidus in the CoGa system. Phase relations and thermodynamic properties of the CoNiGa system based on all experimental information were evaluated. Different properties like enthalpies, activities, sublattice site fraction of vacancies and phase fractions calculated in the system matched well compared to the experimental information used to model the system. Also, the phase equilibria among the gamma (fcc), beta, gamma'(Ni3Ga), delta (Ni5Ga3) and epsilon (Ni13Ga9) were determined at various temperatures.
Chari, Arpita
This report summarizes progress made during the first year of research funding from DOE Grant No. DE-FG26-03NT41792 at the Colorado School of Mines. The period of performance was September 1, 2003 through August of 2004. Composite membranes, consisting of a thin Pd alloy film supported on a porous substrate have been investigated as a means of reducing the membrane cost and improving H{sub 2} flux. An electroless plating technique was utilized to deposit subsequent layers of palladium and copper over zirconia and alumina-based microfilters. The composite membranes thus made were annealed and tested at temperatures ranging from 250 to 500 C, under very high feed pressures (up to 450 psig) using pure gases and gaseous mixtures containing H{sub 2}, CO, CO{sub 2}, H{sub 2}O and H{sub 2}S, with the purpose of determining the effects these variables had on the H{sub 2} permeation rate, selectivity and percent recovery. The inhibition caused by CO/CO{sub 2} gases on a 7 {micro}m thick Pd-Cu composite membrane was less than 17% over a wide range of compositions at 350 C. H{sub 2}S caused a strong inhibition of the H{sub 2} flux of the same Pd-Cu composite membrane, which is accentuated at levels of 100 ppm or higher. The membrane was exposed to 50 ppm three times without permanent damage. At higher H{sub 2}S levels, above 100 ppm the membrane suffered some physical degradation and its performances was severely affected. The use of sweep gases improved the hydrogen flux and recovery of a Pd-Cu composite membrane. Recently, we have been able to dramatically reduce the thickness of these Pd alloy membranes to approximately one micron. This is significant because at this thickness, it is the cost of the porous support that controls the materials cost of a composite Pd alloy membrane, not the palladium inventory. Very recent results show that the productivity of our membranes is very high, essentially meeting the DOE pure hydrogen flux target value set by the DOE Hydrogen Program. These results were obtained when a 1.3-micron-thick Pd{sub 95}Cu{sub 5} (composition given in mass %) alloy film was coated on a Pall Corporation Membralox{reg_sign} T1-70 tubular ceramic substrate. The flux of this membrane would be even higher if the alloy composition was 40 wt. % Cu.
J. Douglas Way
Stress corrosion cracking behavior of Alloy 600 in high temperature water
SCC susceptibility of Alloy 600 in deaerated water at 360 C (statically loaded U-bend specimens) is dependent on microstructure and whether the material was cold-worked and annealed (CWA) or hot-worked and annealed (HWA). All cracking was intergranular, and materials lacking grain boundary carbides were most susceptible to SCC initiation. CWA tubing materials are more susceptible to SCC initiation than HWA ring-rolled forging materials with similar microstructures (optical metallography). In CWA tubing materials, one crack dominated and grew to a visible size. HWA materials with a low hot-working finishing temperature (980 C) and a high-temperature final anneal (>1040 C), with grain boundaries that are fully decorated, developed only microcracks in all specimens. These materials did not develop large, visually detectable cracks, even after more than 300 weeks exposure. A low-temperature thermal treatment (610 C for 7h), which reduces or eliminates SCC in Alloy 600, did not eliminate microcrack formation in high temperature processed HWA materials. Conventional metallographic and analytical electron microscopy (AEM) were done on selected materials to identify the factors responsible for the observed differences in cracking behavior. Major difference between high-temperature HWA and low-temperature HWA and CWA materials was that the high temperature processing and final annealing produced predominantly ``semi-continuous`` dendritic M{sub 7}C{sub 3} carbides along grain boundaries with a minimal amount of intragranular carbides. Lower temperature processing produced intragranular M7C3 carbides, with less intergranular carbides.
Webb, G.L.; Burke, M.G.
Development of Advanced Corrosion-Resistant Fe-Cr-Ni Austenitic Stainless Steel Alloy with Improved High Temperature Strenth and Creep-Resistance
In February of 1999, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Special Metals Corporation-Huntington Alloys (formerly INCO Alloys International, Inc.) to develop a modified wrought austenitic stainless alloy with considerably more strength and corrosion resistance than alloy 800H or 800HT, but with otherwise similar engineering and application characteristics. Alloy 800H and related alloys have extensive use in coal flue gas environments, as well as for tubing or structural components in chemical and petrochemical applications. The main concept of the project was make small, deliberate elemental microalloying additions to this Fe-based alloy to produce, with proper processing, fine stable carbide dispersions for enhanced high temperature creep-strength and rupture resistance, with similar or better oxidation/corrosion resistance. The project began with alloy 803, a Fe-25Cr-35NiTi,Nb alloy recently developed by INCO, as the base alloy for modification. Smaller commercial developmental alloy heats were produced by Special Metals. At the end of the project, three rounds of alloy development had produced a modified 803 alloy with significantly better creep resistance above 815EC (1500EC) than standard alloy 803 in the solution-annealed (SA) condition. The new upgraded 803 alloy also had the potential for a processing boost in that creep resistance for certain kinds of manufactured components that was not found in the standard alloy. The upgraded 803 alloy showed similar or slightly better oxidation and corrosion resistance relative to standard 803. Creep strength and oxidation/corrosion resistance of the upgraded 803 alloy were significantly better than found in alloy 800H, as originally intended. The CRADA was terminated in February 2003. A contributing factor was Special Metals Corporation being in Chapter 11 Bankruptcy. Additional testing, further commercial scale-up, and any potential invention disclosures were not pursued. One objective of this project was to improve the high temperature creep resistance of the recently developed 803 alloy, while another was to have a wrought modified 803 alloy with significantly better creep resistance and corrosion resistance than the commonly used alloy 800H. The project was intended to use the established expertise at ORNL to design specific microalloying element additions to appropriately tailor the microstructure during aging or creep so that fine, stable carbides develop for strength. If possible, oxidation/corrosion resistance at high temperatures would also be enhanced. Optimum processing was to be developed for plate and tube products.
Maziasz, PJ
Renyi Entropy and Free Energy
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.
John C. Baez
A High-Strength Ni-Cr-Mo Alloy for Severe Oil and Gas Environments
About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Development of Advanced Alloys and Coating Systems for Demanding Oil and ...
High-temperature corrosion behavior of iron-aluminide alloys and coatings
An Fe-28 at.% Al-2% Cr alloy doped with Y{sub 2}O{sub 3} showed improved scale adhesion relative to a dispersion-free form of the same composition. However, doping with CeO{sub 2} or La{sub 2}O{sub 3} was detrimental to oxidation behavior. A study of weld-overlay iron-aluminide coatings showed that, those with sufficiently high aluminum concentrations had sulfidation resistance in H{sub 2}S-H{sub 2}-H{sub 2}O-Ar at 800 C equivalent to the most resistant bulk iron aluminides. These corrosion-resistant coatings have the potential to be effective barriers in high-temperature sulfidizing environments provided the appropriate combinations of filler metal, process parameters, and substrate are used to produce adequate aluminum concentrations and minimal chromium contents. Exposures in an oxidizing/sulfidizing environment containing varying amounts of HCI at 450 and 550 C showed that Fe{sub 3}Al alloys had good corrosion resistance.
Tortorelli, P.F.; DeVan, J.H.; Pint, B.A.; Wright, I.G. [Oak Ridge National Lab., TN (United States); Saunders, S.R.J. [National Physical Lab., Teddington (United Kingdom)
Influence of dissolved hydrogen on nickel alloy SCC in high temperature water
Stress corrosion crack growth rate (SCCGR) tests of nickel alloys were conducted at 338 C and 360 C as a function of the hydrogen concentration in high purity water. Test results identified up to a 7 x effect of hydrogen levels in the water on crack growth rate, where the lowest growth rates were associated with the highest hydrogen levels. At 338 C, the crack growth rate decreased as the hydrogen levels were increased. However, different results were observed for the test conducted at 360 C. As the hydrogen level was increased in the 360 C tests, the crack growth rate initially increased, a maximum was exhibited at a hydrogen level of {approximately} 20 scc/kg, and thereafter the crack growth rate decreased. Based on this testing and a review of the commercial literature, the thermodynamic stability of nickel oxide, not the dissolved hydrogen concentration, was identified as a fundamental parameter influencing the susceptibility of nickel alloys to SCC. These test results are discussed in relation to the accuracy of extrapolating high temperature SCC results to lower temperatures.
Morton, D.S.; Attanasio, S.A.; Fish, J.S.; Schurman, M.K. [Lockheed Martin, Schenectady, NY (United States)
Synthesis and optical properties of II-O-VI highly mismatched alloys
We have synthesized ternary and quaternary diluted II-VI oxides using the combination of O ion implantation and pulsed laser melting. CdO{sub x}Te{sub 1-x} thin films with x up to 0.015, and the energy gap reduced by 150 meV were formed by O{sup +}-implantation in CdTe followed by pulsed laser melting. Quaternary Cd{sub 0.6}Mn{sub 0.4}O{sub x}Te{sub 1-x} and Zn{sub 0.88}Mn{sub 0.12}O{sub x}Te{sub 1-x} with mole fraction of incorporated O as high as 0.03 were also formed. The enhanced O incorporation in Mn-containing alloys is believed to be due to the formation of relatively strong Mn-O bonds. Optical transitions associated with the lower (E{sub -}) and upper (E{sub +}) conduction subbands resulting from the anticrossing interaction between the localized O states and the extended conduction states of the host are clearly observed in these quaternary diluted II-VI oxides. These alloys fulfill the criteria for a multiband semiconductor that has been proposed as a material for making high efficiency, single-junction solar cells.
Yu, K.M.; Walukiewicz, W.; Shan, W.; Wu, J.; Beeman, J.W.; Scarpulla, M.A.; Dubon, O.D.; Becla, P.
Entropy of singularities in self-gravitating radiation
The Bekenstein-Hawking entropy suggests that thermodynamics is an intrinsic ingredient of gravity. Here, we explore the idea that requirements of thermodynamic consistency could determine the gravitational entropy in other set-ups. We implement this idea in a simple model: static, spherically symmetric solutions to Einstein's equations corresponding to self-gravitating radiation. We find that the principle of maximum entropy provides a consistent thermodynamic description of the system, only if the entropy includes a contribution from the spacetime singularities that appear in the solutions of Einstein's equations. The form of the singularity entropy is stringently constrained from consistency requirements, so that the existence of a simple expression satisfying these constraints is highly non-trivial, and suggests of a fundamental origin. We find that the system is characterized by three equilibrium phases, and we conduct a preliminary investigation of the associated phase transitions. These results demonstrate the point that gravitational entities other than horizons are endowed with thermodynamic properties.
Charis Anastopoulos; Ntina Savvidou
Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation
This report summarizes progress made during the a three year University Coal Research grant (DEFG26-03NT41792) at the Colorado School of Mines. The period of performance was September 1, 2003 through August of 2006. We made excellent progress toward our goal of contributing to the development of high productivity, sulfur tolerant composite metal membranes for hydrogen production and membrane reactors. Composite Pd and Pd alloy metal membranes with thin metal films (1-7 {micro}m) were prepared on porous stainless steel and ceramic supports that meet or exceed the DOE 2010 and 2015 pure hydrogen flux targets at differential pressure of only 20 psi. For example, a 2 {micro}m pure Pd membrane on a Pall AccuSep{reg_sign} substrate achieved an ideal H{sub 2}/N{sub 2} separation factor of over 6000, with a pure hydrogen flux of 210 SCFH/ft{sup 2} at only 20 psig feed pressure. Similar performance was achieved with a Pd{sub 80}Au{sub 20} composite membrane on a similar stainless steel substrate. Extrapolating the pure hydrogen flux of this PdAu membrane to the DOE Fossil Energy target conditions of 150 psia feed pressure and 50 psia permeate pressure gives a value of 508 SCFH/ft{sup 2}, exceeding the 2015 target. At these thicknesses, it is the support cost that will dominate the cost of a large scale module. In a direct comparison of FCC phase PdCu and PdAu alloys on identical supports, we showed that a Pd{sub 85}Au{sub 15} (mass %) alloy membrane is not inhibited by CO, CO{sub 2}, or steam present in a water-gas shift feed mixture at 400 C, has better resistance to sulfur than a Pd{sub 94}Cu{sub 6} membrane, and has over twice the hydrogen permeance.
J. Douglas Way; Paul M. Thoen
Solid State Joining of High Temperature Alloy Tubes for USC and Heat-Exchanger Systems
The principal objective of this project was to develop materials enabling joining technologies for use in forward looking heat-exchanger fabrication in Brayton cycle HIPPS, IGCC, FutureGen concepts capable of operating at temperatures in excess of 1000{degree}C as well as conventional technology upgrades via Ultra Super-Critical (USC) Rankine-cycle boilers capable of operating at 760{degree}C (1400F)/38.5MPa (5500psi) steam, while still using coal as the principal fossil fuel. The underlying mission in Rankine, Brayton or Brayton-Rankine, or IGCC combined cycle heat engine is a steady quest to improving operating efficiency while mitigating global environmental concerns. There has been a progressive move to higher overall cycle efficiencies, and in the case of fossil fuels this has accelerated recently in part because of concerns about greenhouse gas emissions, notably CO{sub 2}. For a heat engine, the overall efficiency is closely related to the difference between the highest temperature in the cycle and the lowest temperature. In most cases, efficiency gains are prompted by an increase in the high temperature, and this in turn has led to increasing demands on the materials of construction used in the high temperature end of the systems. Our migration to new advanced Ni-base and Oxide Dispersion Strengthened (ODS) alloys poses significant fabrication challenges, as these materials are not readily weldable or the weld performs poorly in the high temperature creep regime. Thus the joining challenge is two-fold to a) devise appropriate joining methodologies for similar/dissimilar Ni-base and ODS alloys while b) preserving the near baseline creep performance in the welded region. Our program focus is on solid state joining of similar and dissimilar metals/alloys for heat exchanger components currently under consideration for the USC, HIPPS and IGCC power systems. The emphasis is to manipulate the joining methods and variables available to optimize joint creep performance compared to the base material creep performance. Similar and dissimilar butt joints were fabricated of MA956, IN740 alloys and using inertia welding techniques. We evaluated joining process details and heat treatments and its overall effect on creep response. Fixed and incrementally accelerated temperature creep tests were performed for similar and dissimilar joints and such incremental creep life data is compiled and reported. Long term MA956-MA556 joint tests indicate a firm 2Ksi creep stress threshold performance at 850{degree}C with a maximum exposure of over 9725 hours recorded in the current program. A Larsen Miller Parameter (LMP) of 48.50 for a 2Ksi test at 850{degree}C was further corroborated with tests at 2Ksi stress at 900{degree}C yielding a LMP=48.80. Despite this threshold the joints exhibit immense temperature sensitivity and fail promptly when test temperature raised above 900{degree}C. In comparison the performance of dissimilar joints was inferior, perhaps dictated by the creep characteristics of the mating nickel-base alloys. We describe a parametric window of joint development, and post weld heat treatment (PWHT) in dissimilar joints with solid solution (IN601, IN617) and precipitate strengthened (IN740) materials. Some concerns are evident regarding the diffusion of aluminum in dissimilar joints during high temperature recrystallization treatments. It is noted that aggressive treatments rapidly deplete the corrosion protecting aluminum reservoir in the vicinity of the joint interface. Subsequently, the impact of varying PWHT has been evaluated in the context on ensuing creep performance.
Bimal Kad
Microstructure and High Temperature Oxidation Behavior of Cr-W Alloys
Cr alloys containing 0-30%W by weight were investigated for use in elevated temperature applications. The alloys were melted in a water-cooled, copper-hearth arc furnace. Microstructure of the alloys was characterized using x-ray diffraction, scanning electron microscopy, and light microscopy. A pseudocyclic oxidation test was employed to study scale formation at 1000şC in dry air. The scale was predominantly chromia and spalled upon cooling. Alloying with aluminum up to 8 weight percent reduced the spalling drastically. Furthermore, aluminizing the surface of the Cr-W alloys completely stopped the spalling.
Dogan, O.N.
Energy, Entropy, Information, and Intelligence
The paper presents a lightweight discussion of relations between energy, entropy, information, and intelligence, based on an analysis of the energy needed for computation.
Cerny, Vladimir
Structure of cadmium selen-telluride alloy films grown by the thermal-screen method under highly nonequilibrium conditions
The results of technological experiments and structural investigations of films of CdSe{sub x}Te{sub 1-x} alloys synthesized by the thermal-screen method on heated and cooled substrates (under highly nonequilibrium conditions) are presented. It is shown that the synthesis of the entire range of compositions of alloy films with the structure from epitaxial to amorphous is possible from the mechanical mixture of CdSe and CdTe powders of the same composition under highly nonequilibrium conditions. The electron diffraction patterns and the microphotographs of film surfaces are reported.
Belyaev, A. P., E-mail: firstname.lastname@example.com; Rubets, V. P.; Antipov, V. V.; Toshkhodzhaev, Kh. A. [St. Petersburg State Technological Institute (Technical University) (Russian Federation)
The alloying of zirconium to improve corrosion resistance has an empirical basis, and satisfactory explanations for the alloying effects are not available. A theory of compensating valencies in the corrosion oxide is proposed, in which cations of lower and higher valence than zirconium (+4) are present in ratios such that electrostatic neutrality is ensured. An example is an alloy containing equimolar amounts of scandium (+3) and niobium (+5). A number of zirconium alloys were prepared in which scandium or yttrium were paired with elements capable of a +5 or +6 valence. The ternary alloys containing scanadium were superior to the alloys combining yttrium. The alloys containing scandium plus molybdenum, tantalum, or tungsten had relatively long lifetimes in steam at 540 deg C and 600 psi as compared with other alloy combinations, including Zircaloy-2. A quenched alloy containing 0.025 wt% Sc and 0.053 at.% Mlo, that is, 0.05 mol.% of each additive, corroded approximately according to a cubic law up to 758 hr, at which potnt the rate suddenly increased in a manner suggesting hydrogen damage. Examination of the oxide film from alloys containing scandium and molybdenum showed only monoclinic ZrO/sub 2/. It is believed that stabilization of this form of ZrO/sub 2/ instead of the cubic or tetragonal forms is a factor in promoting corrosion resistance. In this way the protective character of the film can be improved independently of the addition of cathodes. (auth)
Misch, R.D.; Van Drunen, C.
Cluster formula of Fe-containing Monel alloys with high corrosion-resistance
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.
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: firstname.lastname@example.com [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: email@example.com [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)
Atmospheric Entropy. Part I: Climate Dissipation Structure
Atmospheric entropy and its association with climate dissipation are investigated. The balance equation for entropy is derived through the mean and transient thermal and moisture equations. The entropy production contains the internal and external ...
Jiangnan Li; Petr Chylek
The influence of FeTi and NiTi intermetallide additions on high-temperature oxidation of permalloy alloy
As a rule powder metallurgy Permalloy alloys are used in production of parts for electronic instruments. For the purpose of controlling the magnetic and electrical properties and also the wear (in the case of production of magnetic heads) and corrosion resistance appropriate additions of metals or such compounds as carbides and oxides are added to the alloy. In this work use of FeTi and NiTi intermetallides produced by reaction sintering of powders of pure metals in a protective atmosphere as alloying additions to Permalloy is recommended. The size of the original powders is less than 100 {mu}m. For reaction sintering at temperature 50{degrees}C above the eutectic temperature in the Ti-TiFe and TiNi-Ni systems was selected. The contents of titanium, iron, and oxygen in the FeTi alloy is 51.9, 45.7, and 2.4 wt.%, respectively, and of titanium, nickel, and oxygen in the NiTi alloy 59.6, 31.9, and 4.6 wt.%. High-temperature oxidation in air up to 1300{degrees}C with a rate of change in temperature of 15{degrees}C of type 78N Permalloy with additions of FeTi and NiTi alloys was investigated with use of methods of differential thermal and differential thermogravimetric analyses on an OD-103 derivatograph under nonisothermal conditions. The reaction products were studied by x-ray diffraction phase analysis on a DRON-3 instrument in CoK{sub {alpha}}-radiation. Pure 78N alloy powder with a composition of 78.1% Ni + 19.3% Fe (specimen 1) and also with additions of 1% FeTi (specimen 2) and 1% NiTi (specimen 3) were subjected to oxidation.
Klimenko, V.N.; Lavrenko, V.A.; Panasyuk, O.A.; Blasova, O.V.; Protsenko, T.G. [Inst. of Materials Science, Kiev (Ukraine)
High mobility two-dimensional electron gases in nitride heterostructures with high Al composition AlGaN alloy barriers
We report high-electron mobility nitride heterostructures with >70% Al composition AlGaN alloy barriers grown by molecular beam epitaxy. Direct growth of such AlGaN layers on GaN resulted in hexagonal trenches and a low mobility polarization-induced charge. By applying growth interruption at the heterojunction, the surface morphology improved dramatically and the room temperature two-dimensional electron gas (2DEG) mobility increased by an order of magnitude, exceeding 1300 cm{sup 2}/V s. The 2DEG density was tunable at 0.4-3.7x10{sup 13}/cm{sup 2} by varying the total barrier thickness (t). Surface barrier heights of the heterostructures were extracted and exhibited dependence on t.
Li Guowang; Cao Yu; Xing Huili Grace; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)
Quantum games and minimum entropy
This paper analyze Nash's equilibrium (maximum utility MU) and its relations with the order state(minimum entropy ME). I introduce the concept of minimum entropy as a paradigm of both Nash-Hayek's equilibrium. The ME concept is related to Quantum Games. ...
Edward Jiménez
design of new mg lean alloys with high formability and strength ...
Jul 20, 2012 ... In the last decade, thermodynamic databases for Mg alloys have ... of all available thermodynamic and phase diagram data in literature. As the ...
High capacity, reversible alloying reactions in SnSb/C nanocomposites for Na-ion battery applications
A new SnSb/C nanocomposite based on Na alloying reactions is demonstrated as anode for Na-ion battery applications. The electrode can achieve an exceptionally high capacity (544 mA h g{sup -1}, almost double that of intercalation carbon materials), good rate capacity and cyclability (80% capacity retention over 50 cycles) for Na-ion storage.
Xiao, Lifen; Cao, Yuliang; Xiao, Jie; Wang, Wei; Kovarik, Libor; Nie, Zimin; Liu, Jun
High Temperature Oxidation of Silicon Carbide and Advanced Iron-Based Alloys in Steam-Hydrogen Environments
A side by side comparison of the oxidation behavior of zirconium alloys with SiC materials and advanced iron-based alloys is provided. Oxidation tests were conducted in steam and steam-hydrogen environments at 800-1350 C and 0.34-2MPa for durations up to 48 hours. Monolithic SiC specimens as well as SiC/SiC composites were examined during the study where the material recession mechanism appeared to be governed by silica layer volatilization at the surface for CVD SiC. A wide set of austenitic and ferritic steels were also examined where a critical Cr content (>20 wt.%) was shown to be necessary to achieve oxidation resistance at high temperatures. SiC materials and alumina-forming ferritic steels exhibited slowest oxidation kinetics; roughly two orders of magnitude lower than zirconium alloys.
Terrani, Kurt A [ORNL; Keiser, James R [ORNL; Brady, Michael P [ORNL; Cheng, Ting [ORNL; Silva, G W Chinthaka M [ORNL; Pint, Bruce A [ORNL; Snead, Lance Lewis [ORNL
Properties of Ultra-High-Strength Custom Age 625 Plus Alloy
testing. Alloy. 718 bars were cold drawn 26% to O-758-inch. (19.3-mm) ..... and Aaed Bars. 0.2% Y.S.. U.T.S.. Elong. R.A.. Notch T.S.*. NTS/UTS. Alloy ksi. (MPa).
High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability
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.
Maziasz, Philip J. (Oak Ridge, TN); Goodwin, Gene M. (Lenoir City, TN); Liu, Chain T. (Oak Ridge, TN)
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.
Maziasz, P.J.; Goodwin, G.M.; Liu, C.T.
High Efficiency Triple-Junction Amorphous Silicon Alloy Photovoltaic Technology, Final Technical Report, 6 March 1998 - 15 October 2001
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.
Guha, S.
A history of graph entropy measures
This survey seeks to describe methods for measuring the entropy of graphs and to demonstrate the wide applicability of entropy measures. Setting the scene with a review of classical measures for determining the structural information content of graphs, ... Keywords: Entropy, Graph complexity, Graph entropy, Graphs, Information inequalities, Information measures, Information theory, Structural complexity
Matthias Dehmer; Abbe Mowshowitz
Valence Band Structure of Highly Efficient p-type Thermoelectric PbTe-PbS Alloys
New experimental evidence is given relevant to the temperature-dependence of valence band structure of PbTe and PbTe1-xSx alloys (0.04 x 0.12), and its effect on the thermoelectric figure of merit zT. The x = 0.08 sample has zT ~ 1.55 at 773K. The magnetic field dependence of the high-temperature Hall resistivity of heavily p-type (> 1019 cm-3) Na-doped PbTe1-xSx reveals the presence of high-mobility electrons. This put in question prior analyses of the Hall coefficient and the conclusion that PbTe would be an indirect gap semiconductor at temperatures where its zT is optimal. Possible origins for these electrons are discussed: they can be induced by photoconductivity, or by the topology of the Fermi surface when the L and -bands merge. Negative values for the low-temperature thermopower are also observed. Our data show that PbTe continues to be a direct gap semiconductor at temperatures where the zT and S2 of p-type PbTe are optimal e.g. 700-900K. The previously suggested temperature induced rapid rise in energy of the heavy hole LVB relative to the light hole UVB is not supported by the experimental data.
Jaworski, C. M. [Ohio State University; Nielsen, Mechele [Ohio State University; Wang, Hsin [ORNL; Girard, Steven N. [Northwestern University, Evanston; Cai, Wei [ORNL; Porter, Wallace D [ORNL; Kanatzidis, Mercouri G. [Northwestern University, Evanston; Heremans, J. P. [Ohio State University
Ultrasonic properties of low solvus high refractory (LSHR) super alloy disk material
Measurements are made for ultrasonic linear and nonlinear properties of the powder metallurgy disk alloy LSHR material designed with a relatively low {gamma}' precipitate solvus temperature and high refractory element content. This allows versatile heat treatment processing which results in high tensile, creep and fatigue properties depending on the grain size controlled through proper selection of solution heat treatment temperatures relative to the {gamma}' precipitate solvus temperature. Sound velocity and attenuation for both longitudinal and shear modes at various frequencies from 5 to 20 MHz help to identify and quantify the size of transition zone nondestructively between the small grain ({approx}10 {mu}m) and the large grain ({approx}100 {mu}m) zones. The shear wave velocity measurements taken by aligning the transducer polarization direction parallel and perpendicular to the grain transition direction reveal some results that we do not fully understand at this time and will be the basis of future research. Similarly, measurements of the acoustic nonlinearity parameter show some variations that may originate from uncertain sources.
Na, Jeong K. [University of Dayton Research Institute, 300 College Park, Dayton, OH 45469 (United States); Blodgett, Mark [Air Force Research Laboratory (AFRL/RXLP) Wright-Patterson AFB, OH 45433 (United States)
Deformation, Damage, and Fracture of Light Metals and Alloys
The three most highly used light metals and alloys are magnesium, aluminum, and titanium alloys. These alloys are widely utilized to manufacture structural ...
Accelerating Observers, Area and Entropy
We consider an explicit example of a process, where the entropy carried by radiation through an accelerating two-plane is proportional to the decrease in the area of that two-plane even when the two-plane is not a part of any horizon of spacetime. Our results seem to support the view that entropy proportional to area is possessed not only by horizons but by all spacelike two-surfaces of spacetime.
Makela, J
Jarmo Makela
NiTiHf High-Temperature Shape-Memory Alloys for near Term ...
Development of a SMA-Based Drive Unit for Prehension Orthoses to Support Disabled People · Effect of H in Metals and Alloys: An Application to bcc W and NiTi ...
Solid state thin film battery having a high temperature lithium alloy anode
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.
Hobson, David O. (Oak Ridge, TN)
Metallic interconnects in SOFC stacks, perform in challenging environment, as they are simultaneously exposed to a reducing environment (e.g. hydrogen, reformate) on one side and an oxidizing environment (e.g. air) on the other side at elevated temperatures. To understand the oxidation/corrosion behavior of metals and alloys under the dual exposures and assess their suitability, selected metals and alloys, including nickel, Fe-Cr and Ni-Cr base chromia forming alloys, alumina forming Fecralloy®, were investigated. It was found that the oxidation/corrosion behavior of metals and alloys in the presence of dual environment can be significantly different in terms of scale structure and/or chemistry from their exposure in a single oxidizing or reducing atmosphere. The anomalous oxidization/corrosion is attributed to the presence of hydrogen diffusion flux from the fuel side to the air side under the influence of a hydrogen gradient across the metallic substrates.
Yang, Z Gary; Xia, Gordon; Walker, Matthew S.; Wang, Chong M.; Stevenson, Jeffry W.; Singh, Prabhakar
High Growth Rate of Epitaxial Silicon-Carbon Alloys by High-Order Silane Precursor and Chemical Vapor Deposition
rates typically achieved by disilane and silane, respectively, at 575o C. The rate at present is limited precursor HOS than disilane in CVD, even at lower temperatures. Our current growth rates of Si1-yCy alloys
Entropy in Climate Models. Part I: Vertical Structure of Atmospheric Entropy Production
The vertical atmospheric entropy structure has been investigated using one-dimensional radiative–convective models. A method for evaluating radiation entropy is proposed. In the models, the entropy radiation is dealt with in a way parallel to the ...
J. Li; Petr Chýlek; G. B. Lesins
Entropy in Climate Models. Part II: Horizontal Structure of Atmospheric Entropy Production
The global horizontal structure of atmospheric entropy has been investigated. In energy balance models, the horizontal distribution of the atmospheric internal entropy production rate has been obtained. Based on the entropy balance relation, this ...
J. Li; Petr Chylek
All Inequalities for the Relative Entropy
The relative entropy of two n-party quantum states is an important quantity exhibiting, for example, the extent to which the two states are different. The relative entropy of the states formed by reducing two n-party to a smaller number $m$ of parties is always less than or equal to the relative entropy of the two original n-party states. This is the monotonicity of relative entropy. Using techniques from convex geometry, we prove that monotonicity under restrictions is the only general inequality satisfied by relative entropies. In doing so we make a connection to secret sharing schemes with general access structures. A suprising outcome is that the structure of allowed relative entropy values of subsets of multiparty states is much simpler than the structure of allowed entropy values. And the structure of allowed relative entropy values (unlike that of entropies) is the same for classical probability distributions and quantum states.
Ben Ibinson; Noah Linden; Andreas Winter
X-ray-induced dissociation of H.sub.2O and formation of an O.sub.2-H.sub.2 alloy at high pressure
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.
Mao, Ho-kwang (Washington, DC); Mao, Wendy L. (Washington, DC)
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.
Hobson, D.O.
High post-irradiation ductility thermomechanical treatment for precipitation strengthened austenitic alloys
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.
Laidler, James J. (Richland, WA); Borisch, Ronald R. (Kennewick, WA); Korenko, Michael K. (Rockville, MD)
Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems
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) .
G. RObert Odette; Takuya Yamamoto
-phase strengthened Fe-base alloys for improved elevated temperature strength in fossil energy system components-temperature strength is a major issue for hot components in advanced fossil energy conversion and combustion systems-containing environments such as those encountered in advanced fossil energy steam plants. Controlled Oxidation for Near
High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances
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.
K. Coulter
On Entropy Transmission for Quantum Channels
In this paper a notion of entropy transmission of quantum channels is introduced as a natural extension of Ohya's entropy. Here by quantum channel is meant unital completely positive mappings (ucp) of $B(H)$ into itself, where $H$ is an infinite dimensional Hilbert space. Using a representation theorem of ucp mapping we associate to every ucp map a uniquely determined state, and prove that entropy of ucp map is less then Ohya's entropy of the associated state.
Nasir Ganikhodjaev; Farrukh Mukhamedov
Standard practice for evaluation of disbonding of bimetallic stainless alloy/steel plate for use in high-pressure, high-temperature refinery hydrogen service
1.1 This practice covers a procedure for the evaluation of disbonding of bimetallic stainless alloy/steel plate for use in refinery high-pressure/high-temperature (HP/HT) gaseous hydrogen service. It includes procedures to (1) produce suitable laboratory test specimens, (2) obtain hydrogen charging conditions in the laboratory that are similar to those found in refinery HP/HT hydrogen gas service for evaluation of bimetallic specimens exposed to these environments, and (3) perform analysis of the test data. The purpose of this practice is to allow for comparison of data among test laboratories on the resistance of bimetallic stainless alloy/steels to hydrogen-induced disbonding (HID). 1.2 This practice applies primarily to bimetallic products fabricated by weld overlay of stainless alloy onto a steel substrate. Most of the information developed using this practice has been obtained for such materials. The procedures described herein, may also be appropriate for evaluation of hot roll bonded, explosive bonded...
American Society for Testing and Materials. Philadelphia
This report summarizes progress made during the second year of research funding from DOE Grant DE-FG26-03NT41792 at the Colorado School of Mines. The period of performance was September 1, 2004 through August of 2005. We have reformulated our Pd plating process to minimize the presence of carbon contamination in our membranes. This has improved durability and increased permeability. We have developed techniques for plating the outside diameter of ceramic and metal substrate tubes. This configuration has numerous advantages including a 40% increase in specific surface area, the ability to assay the alloy composition non-destructively, the ability to potentially repair defects in the plated surface, and the ability to visually examine the plated surfaces. These improvements have allowed us to already meet the 2007 DOE Fossil Energy pure H{sub 2} flux target of 100 SCFH/ft{sup 2} for a hydrogen partial pressure difference of 100 psi with several Pd-Cu alloy membranes on ceramic microfilter supports. Our highest pure H{sub 2} flux on inexpensive, porous alumina support tubes at the DOE target conditions is 215 SCFH/ft{sup 2}. Progress toward meeting the other DOE Fossil Energy performance targets is also summarized. Additionally, we have adapted our membrane fabrication procedure to apply Pd and Pd alloy films to commercially available porous stainless steel substrates. Stable performance of Pd-Cu films on stainless steel substrates was demonstrated over a three week period at 400 C. Finally, we have fabricated and tested Pd-Au alloy membranes. These membranes also exceed both the 2007 and 2010 DOE pure H{sub 2} flux targets and exhibit ideal H{sub 2}/N{sub 2} selectivities of over 1000 at partial pressure difference of 100 psi.
High strength Sn-Mo-Nb-Zr alloy tubes and method of making same
Tubes for use in nuclear reactors fabricated from a quaternary alloy comprising 2.5-4.0 wt% Sn, 0.5-1.5 wt% Mo, 0.5-1.5 wt% Nb, balance essentially Zr. The tubes are fabricated by a process of hot extrusion, heat treatment, cold working to size and age hardening, so as to produce a microstructure comprising elongated .alpha. grains with an acicular transformed .beta. grain boundary phase.
Cheadle, Brian A. (Deep River, CA)
Intracluster gas pressure, entropy injection and redshift evolution
We study the effect of entropy injection in the intracluster medium (ICM) in light of the recent observationally determined universal pressure profile of the ICM. Beginning with a power-law entropy profile that is expected in the absence of any feedback, we show that a simple universal prescription of entropy injection results in the final, observed universal pressure profile. This simple prescription has two components, one associated with an overall increase in entropy and another associated with injection in the central parts of the cluster. Importantly, both the components of entropy injection are needed to produce the final universal pressure profile. This is indicative of a need of both preheating the ICM as well {\\it in situ} AGN/SNe heating. We demonstrate the usefulness of the method by extending the calculations to clusters at high redshift, and predict redshift evolution of cluster scaling relations that can be tested against data. We show that the self-similar evolution of the universal pressure p...
Nath, Biman B
Ductile transplutonium metal alloys
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.
Conner, W.V.
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.
Titanium Alloys
Table 5(c)Â Â Â Compositions of various beta titanium alloys...of various beta titanium alloys Designation Specifications Impurity limits,
Alloy Designations
Table 1Â Â Â Nominal composition and composition limits of aluminum alloy castings...of aluminum alloy castings Based on industry handbooks, notably Aluminum Association
Stoichiometric growth of high Curie temperature heavily alloyed GaMnAs
Heavily alloyed, 100 nm Ga{sub 1-x}Mn{sub x}As (x>0.1) films are obtained via low-temperature molecular beam epitaxy by utilizing a combinatorial technique which allows systematic control of excess arsenic during growth. Reproducible electronic, magnetic, and structural properties are optimized in a narrow range of stoichiometric growth conditions. In contrast to a prediction of the Zener model of hole-mediated ferromagnetism, the Curie temperature of the stoichiometric material is independent of x (for x>0.1), while substitutional Mn content is proportional to x within a large window of growth conditions.
Mack, S.; Myers, R. C.; Heron, J. T.; Gossard, A. C.; Awschalom, D. D. [Center for Spintronics and Quantum Computation, University of California, Santa Barbara, California 93106 (United States)
Entropy Production in Simple Special Relativistic Fluids
It is well known that, in the absence of external forces, simple non-relativistic fluids involve entropy production only through heat conduction and shear viscosity. In this work, it is shown that a number density gradient contributes to the local entropy production of a simple relativistic fluid using special relativistic kinetic theory. Also, the presence of an external field may cause strictly relativistic contributions to the entropy production, a fact not widely recognized. The implications of these effects are thoroughly discussed.
D. Brun-Battistini; A. Sandoval-Villalbazo; A. L. Garcia-Perciante
An Improved CVM Entropy Functional for BCC Alloys
Materials Genomics Past & Future: From CALPHAD to Flight · Microstructure Stability of Multi-Materials Systems with Adaptive Microstructures · Modeling of ...
Multi-Objective Optimization of a Wrought Magnesium Alloy for High Strength and Ductility
An optimization technique is coupled with crystal plasticity based finite element (CPFE) computations to aid the microstructural design of a wrought magnesium alloy for improved strength and ductility. The initial microstructure consists of a collection of sub-micron sized grains containing deformation twins. The variables used in the simulations are crystallographic texture, and twin spacing within the grains. It is assumed that plastic deformation occurs mainly by dislocation slip on two sets of slip systems classified as hard and soft modes. The hard modes are those slip systems that are inclined to the twin planes and the soft mode consists of dislocation glide along the twin plane. The CPFE code calculates the stress-strain response of the microstructure as a function of the microstructural parameters and the length-scale of the features. A failure criterion based on a critical shear strain and a critical hydrostatic stress is used to define ductility. The optimization is based on the sequential generation of an initial population defined by the texture and twin spacing variables. The CPFE code and the optimizer are coupled in parallel so that new generations are created and analyzed dynamically. In each successive generation, microstructures that satisfy at least 90% of the mean strength and mean ductility in the current generation are retained. Multiple generation runs based on the above procedure are carried out in order to obtain maximum strength-ductility combinations. The implications of the computations for the design of a wrought magnesium alloy are discussed. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.
Radhakrishnan, Balasubramaniam [ORNL; Gorti, Sarma B [ORNL; Patton, Robert M [ORNL; Simunovic, Srdjan [ORNL
Alloy materials
An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.
Hans Thieme, Cornelis Leo (Westborough, MA); Thompson, Elliott D. (Coventry, RI); Fritzemeier, Leslie G. (Acton, MA); Cameron, Robert D. (Franklin, MA); Siegal, Edward J. (Malden, MA)
Development of high stable-efficiency, triple-junction a-Si alloy solar cells. Annual subcontract report, July 18, 1994--July 17, 1995
This report describes work performed by Energy Conversion Devices, Inc. (ECD) under a 3-year, cost-shared amorphous silicon (a-Si) research program to develop advanced technologies and to demonstrate stable 14%-efficient, triple-junction a-Si alloy solar cells. The technologies developed under the program will then be incorporated into ECD`s continuous roll-to-roll deposition process to further enhance ECD`s photovoltaic manufacturing technology. In ECD`s solar cell design, triple-junction a-Si alloy solar cells are deposited onto stainless-steel substrates coated with Ag/ZnO back-reflector layers. This type of cell design enabled ECD to use a continuous roll- to-roll deposition process to manufacture a-Si PV materials in high volume at low cost. Using this cell design, ECD previously achieved 13.7% initial solar cell efficiency using the following features: (1) a triple-junction, two-band-gap, spectrum-splitting solar cell design; (2) a microcrystalline silicon p-layer; (3) a band-gap-profiled a- SiGe alloy as the bottom cell i-layer; (4) a high-performance AgZnO back-reflector; and (5) a high-performance tunnel junction between component cells. ECD also applied the technology into its 2-MW/yr a- Si production line and achieved the manufacturing of 4-ft{sup 2} PV modules with 8% stable efficiency. During this program, ECD is also further advancing its existing PV technology toward the goal of 14% stable solar cells by performing the following four tasks: (1) improving the stability of the intrinsic a-Si alloy materials; (2) improving the quality of low-band-gap a-SiGe alloy; (3) improving p{sup +} window layers, and (4) developing high stable-efficiency triple-junction a-Si alloy solar cells.
Deng, X. [Energy Conversion Devices, Inc., Troy, MI (United States)
Maximum entropy distribution of stock price fluctuations
The principle of absence of arbitrage opportunities allows obtaining the distribution of stock price fluctuations by maximizing its information entropy. This leads to a physical description of the underlying dynamics as a random walk characterized by a stochastic diffusion coefficient and constrained to a given value of the expected volatility, taking in this way into account the information provided by the existence of an option market. This model is validated by a comprehensive comparison with observed distributions of both price return and diffusion coefficient. Expected volatility is the only parameter in the model and can be obtained by analysing option prices. We give an analytic formulation of the probability density function for price returns which can be used to extract expected volatility from stock option data. This distribution is of high practical interest since it should be preferred to a Gaussian when dealing with the problem of pricing derivative financial contracts.
Bartiromo, Rosario
Influence of Irradiation and Stress/Strain on the In-Reactor Behavior of High-Purity Stainless Steels and Ni-Base Alloys -- Task B.
Annealed austenitic stainless steels and nickel-base alloys that are stressed close to or above their yield strength at significant neutron fluence can become susceptible to irradiation assisted stress corrosion cracking (IASCC). This report continues an earlier study examining the effect of coolant chemistry and high fluence on the susceptibility of several heats of austenitic materials in both the PWR and BWR environments.
Development of high, stable-efficiency triple-junction a-Si alloy solar cells. Final technical report
This report summarizes Energy Conversion Devices, Inc.`s (ECD) research under this program. ECD researchers explored the deposition of a-Si at high rates using very-high-frequency plasma MHz, and compared these VHF i-layers with radio-frequency (RF) plasma-deposited i-layers. ECD conducted comprehensive research to develop a {mu}c-Si p{sup +} layer using VHF deposition process with the objectives of establishing a wider process window for the deposition of high-quality p{sup +} materials and further enhancing their performance of a-Si solar cells by improving its p-layers. ECD optimized the deposition of the intrinsic a-Si layer and the boron-doped {mu}c-Si p{sup +} layer to improve the V{sub oc}. Researchers deposited wide-bandgap a-Si films using high hydrogen dilution; investigated the deposition of the ZnO layer (for use in back-reflector) using a sputter deposition process involving metal Zn targets; and obtained a baseline fabrication for single-junction a-Si n-i-p devices with 10.6% initial efficiency and a baseline fabrication for triple-junction a-Si devices with 11.2% initial efficiency. ECD researchers also optimized the deposition parameters for a-SiGe with high Ge content; designed a novel structure for the p-n tunnel junction (recombination layer) in a multiple-junction solar cell; and demonstrated, in n-i-p solar cells, the improved stability of a-Si:H:F materials when deposited using a new fluorine precursor. Researchers investigated the use of c-Si(n{sup +})/a-Si alloy/Pd Schottky barrier device as a tool for the effective evaluation of photovoltaic performance on a-Si alloy materials. Through alterations in the deposition conditions and system hardware, researchers improved their understanding for the deposition of uniform and high-quality a-Si and a-SiGe films over large areas. ECD researchers also performed extensive research to optimize the deposition process of the newly constructed 5-MW back-reflector deposition machine.
Deng, X.; Jones, S.J.; Liu, T.; Izu, M. [Energy Conversion Devices, Inc., Troy, MI (United States)
Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt
Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.
Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV
The Behaviour Of Zirconium Alloys In Santowax OM Organic Coolant At High Temperature
Zirconium alloys have been exposed to Santowax OM at temperatures of 320 to 400 deg C for times as long as 5000 hours. Short-term experiments (less than 2 weeks) were done in stainless-steel bombs and small out-of-pile loops. The X-7 organic loop in the NRX reactor was used to study long-term oxidation and hydriding both in-flux and out-of-flux. The results obtained lead to several tentative conclusions. 1. Aluminum cladding serves as an effective hydrogen barrier. 2. Considerable protection against hydriding is given by zirconium oxide, provided impurities in the organic are carefully controlled. Hydriding is greatly enhanced by the presence of chlorine in the coolant. 4. Hydriding is somewhat enhanced by neutron irradiation. Of considerable significance is the fact that a Zircaloy-4 in-reactor test section of the X-7 loop was exposed to Santowax OM at 320 to 400 deg C for more than 5000 hours without excessive hydriding. (auth)
Sawatzky, A.
Entanglement Entropy at Large Central Charge
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.
Hartman, Thomas
Thomas Hartman
A high-density quaternary tungsten-base alloy having high mechanical strength and good machinability composed of about 2 wt.% Ni, 3 wt.% Cu, 5 wt.% Pb, and 90wt.% W is described. This alloy can be formed by the powder metallurgy technique of hot pressing in a graphite die without causing a reaction between charge and the die and without formation of a carbide case on the final compact, thereby enabling re-use of the graphite die. The alloy is formable at hot- pressing temperatures of from about 1200 to about 1350 deg C. In addition, there is little component shrinkage, thereby eliminating the necessity of subsequent extensive surface machining.
Schell, D.H.; Sheinberg, H.
Highly Scalable Genotype Phasing by Entropy Minimization
A Single Nucleotide Polymorphism (SNP) is a positionin the genome at which two or more of the possible fournucleotides occur in a large percentage of the population. SNPsaccount for most of the genetic variability between individuals,and mapping SNPs ... Keywords: Single Nucleotide Polymorphism, haplotype, genotype phasing, algorithm.
Alexander Gusev; Ion I. M?ndoiu; Bogdan Pa?aniuc
Corrosion Behavior of NiCrFe Alloy 600 in High Temperature, Hydrogenated Water
The corrosion behavior of Alloy 600 (UNS N06600) is investigated in hydrogenated water at 260 C. The corrosion kinetics are observed to be parabolic, the parabolic rate constant being determined by chemical descaling to be 0.055 mg dm{sup -2} hr{sup -1/2}. A combination of scanning and transmission electron microscopy, supplemented by energy dispersive X-ray spectroscopy and grazing incidence X-ray diffraction, are used to identify the oxide phases present (i.e., spinel) and to characterize their morphology and thickness. Two oxide layers are identified: an outer, ferrite-rich layer and an inner, chromite-rich layer. X-ray photoelectron spectroscopy with argon ion milling and target factor analysis is applied to determine spinel stoichiometry; the inner layer is (Ni{sub 0.7}Fe{sub 0.3})(Fe{sub 0.3}Cr{sub 0.7}){sub 2}O{sub 4}, while the outer layer is (Ni{sub 0.9}Fe{sub 0.1})(Fe{sub 0.85}Cr{sub 0.15}){sub 2}O{sub 4}. The distribution of trivalent iron and chromium cations in the inner and outer oxide layers is essentially the same as that found previously in stainless steel corrosion oxides, thus confirming their invariant nature as solvi in the immiscible spinel binary Fe{sub 3}O{sub 4}-FeCr{sub 2}O{sub 4} (or NiFe{sub 2}O{sub 4}-NiCr{sub 2}O{sub 4}). Although oxidation occurred non-selectively, excess quantities of nickel(II) oxide were not found. Instead, the excess nickel was accounted for as recrystallized nickel metal in the inner layer, as additional nickel ferrite in the outer layer, formed by pickup of iron ions from the aqueous phase, and by selective release to the aqueous phase.
SE Ziemniak; ME Hanson
This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.
G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua
The High Cycle Fatigue and Final Fracture Behavior of Alloy Steel ...
Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable ...
Mechanical Properties of Welds in Commercial Alloys for High-Temperature Gas-Cooled Reactor Components
James R. Lindgren; Brian E. Thurgood; Robin H. Ryder; Chia-Chuan Li
Spark Plasma Sintering of Tungsten-Rhenium Alloys for Very High ...
In this study, the tungsten-rhenium microstructure was optimized using alternative techniques such as high energy ball milling and spark plasma sintering, which ...
High-temperature Creep-Fatigue Behavior Study of INCONEL Alloy ...
Abstract Scope, Spallation-neutron-source-yielded multiple diffraction combining with the in-situ high-temperature experimental environment was applied to ...
High Temperature Aging Study on Long-Term Aged Alloy 617 and ...
In order to gain a better understanding of the high-temperature degradation process of these materials, long-term (up to 10000 hours) aging experiments have ...
Influence of Water Chemistry on Copper Alloy Corrosion in High Purity Feedwater
Uncontrolled copper transport activity represents a potentially significant source of performance and reliability loss to fossil plants with mixed-metallurgy feedwater systems. Continuing utility experiences with severe copper fouling on high pressure turbines identified the need for fundamental research to improve control of copper corrosion in low pressure (LP) and high pressure (HP) feedwater heater environments.
The Quantum Entropy Cone of Stabiliser States
We investigate the universal linear inequalities that hold for the von Neumann entropies in a multi-party system, prepared in a stabiliser state. We demonstrate here that entropy vectors for stabiliser states satisfy, in addition to the classic inequalities, a type of linear rank inequalities associated with the combinatorial structure of normal subgroups of certain matrix groups. In the 4-party case, there is only one such inequality, the so-called Ingleton inequality. For these systems we show that strong subadditivity, weak monotonicity and Ingleton inequality exactly characterize the entropy cone for stabiliser states.
Noah Linden; František Matúš; Mary Beth Ruskai; Andreas Winter
Decrease of Entropy and Chemical Reactions
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.
Yi-Fang Chang
Co-Cr-Mo Alloys Production by Self Propagating High Temperature ...
Chemical Enrichment of Precious Metals in Iron Sulfides Using Microwave Energy · Chloridizing ... Co-Gasification Behavior of Metallurgical Coke with High and Low Reactivity .... Thermal Plasma Torches for Metallurgical Applications.
Short-Crack Response of Alloy 182 Weld Metal Undergoing Stress Corrosion Cracking in High-Temperature PWR Primary Water
Mechanistic investigations of environmentally assisted cracking (EAC), to date, have focused more on propagation relative to initiation. At the same time, components spend most of their life in the initiation and "short-crack" growth regimes. Prior exploratory work conducted at General Electric Global Research Center (GE GRC) showed that stainless steels, Alloy 600, and Alloy 182 weld metal exhibit lower average growth rates when the cracks are very short or small (1050 m). In those tests, the transition...
Some calculable contributions to entanglement entropy
Entanglement entropy appears as a central property of quantum systems in broad areas of physics. However, its precise value is often sensitive to unknown microphysics, rendering it incalculable. By considering parametric ...
Hertzberg, Mark Peter
Entropy Generation Analysis of Desalination Technologies
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 ...
Mistry, Karan Hemant
Algorithmic entropy, phase transition, and smart systems
A smart system exhibits the three important properties: (i) interactive, collective, coordinated and parallel operation (ii) self-organization through emergent properties (iii) adaptive and flexible operation. A hierarchy based on metric entropy is suggested ...
E. V. Krishnamurthy
Transfer Entropy Analysis of the Stock Market
In terms of transfer entropy, we investigated the strength and the direction of information transfer in the US stock market. Through the directionality of the information transfer, the more influential company between the correlated ones can be found and also the market leading companies are selected. Our entropy analysis shows that the companies related with energy industries such as oil, gas, and electricity influence the whole market.
Baek, S K; Kwon, O; Moon, H T; Baek, Seung Ki; Jung, Woo-Sung; Kwon, Okyu; Moon, Hie-Tae
Uncontrolled copper transport represents a potentially significant source of performance and reliability loss to fossil plants with mixed-metallurgy feedwater systems. Recent utility experiences with severe copper turbine fouling identified the need for fundamental research to improve control of copper corrosion in low-pressure (LP) and high-pressure (HP) feedwater heater environments.
Entropy Perturbations in N-flation Model
In this paper we study the entropy perturbations in the N-flation model by using the $\\d\\ma{N}$ formalism. We calculate the entropy corrections to the power spectrum of the overall curvature perturbation $P_{\\z}$. We obtain an analytic form of transfer coefficient $T^2_{\\ma{R}\\ma{S}}$, which describes the correlations between the curvature and entropy perturbations, and investigate its numerical behavior. Our results show that the entropy perturbations cannot be neglected in the N-flation model, because the amplitude of entropy components is approximately in the same order as the adiabatic one at the end of inflation $T^2_{\\ma{R}\\ma{S}}\\sim\\ma{O}(1)$. Then the spectral index $n_S$ is calculated and it is found that the index becomes smaller after the entropy modes are taken into account, i.e., the spectrum becomes redder than the pure adiabatic one. Finally we study the modified consistency relation of the N-flation model, and find that the tensor-to-scalar ratio ($r\\simeq0.006$) is greatly suppressed by the ...
Cai, Rong-Gen; Piao, Yun-Song
High Accuracy U-235 Enrichment Verification Station for Low Enriched Uranium Alloys
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.
Lillard, C. R.; Hayward, J. P.; Williamson, M. R.
Amorphous metal alloy and composite
Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.
Wang, Rong (Richland, WA); Merz, Martin D. (Richland, WA)
A brazing alloy which, in the molten state, is characterized by excellent wettability and flowability, said alloy being capable of forming a corrosion resistant brazed joint wherein at least one component of said joint is graphite and the other component is a corrosion resistant refractory metal, said alloy consisting essentially of 20 to 50 per cent by weight of gold, 20 to 50 per cent by weight of nickel, and 15 to 45 per cent by weight of molybdenum. (AEC)
Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.
Welding of dissimilar alloys for high temperature heat exchangers for SOFC
Reduction in the cost of balance of plant applications is one of the top priority focus areas for the successful implementation of solid oxide fuel cell technology. High temperature heat exchangers are employed to heat cathode air utilizing either hot gases coming from the anode side of the stack or other hot gases generated by external processes. In order to reduce the cost of heat exchangers, it may be necessary to apply several different materials, each in a different temperature zone, for the construction of the heat exchanger. This technique would require the joining of dissimilar materials in the construction. In this work, welding of commercial candidate dissimilar materials is explored. Filler materials were identified using equilibrium phase diagrams and thermodynamic simulation software. Autogenous welding was performed and the welding defects were characterized. Finally, experimental weld microstructures were compared to phases predicted by the simulations.
Wilson, R.D.; Hatem, J.; Dogan, O.N.; King, P.E.
Entanglement, Purity, and Information Entropies in Continuous Variable Systems
Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal ({\\em i.e.}referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss of information about the state makes it impossible to distinguish between quantum and classical correlations. Here we show how the joint knowledge of the global and marginal degrees of information of a quantum state, quantified by the purities or in general by information entropies, provides an accurate characterization of its entanglement. In particular, for Gaussian states of continuous variable systems, we classify the entanglement of two--mode states according to their degree of total and partial mixedness, comparing the different roles played by the purity and the generalized $p-$entropies in quantifying the mixedness and bounding the entanglement. We prove the existence of strict upper and lower bounds on the entanglement and the existence of extremally (maximally and minimally) entangled states at fixed global and marginal degrees of information. This results allow for a powerful, operative method to measure mixed-state entanglement without the full tomographic reconstruction of the state. Finally, we briefly discuss the ongoing extension of our analysis to the quantification of multipartite entanglement in highly symmetric Gaussian states of arbitrary $1 \\times N$-mode partitions.
Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati
Maximum entropy principal for transportation
In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.
Bilich, F. [University of Brasilia (Brazil); Da Silva, R. [National Research Council (Brazil)
Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration
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.
Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen
A binary zirconiuin--antimony alloy is presented which is corrosion resistant and hard containing from 0.07% to 1.6% by weight of Sb. The alloys have good corrosion resistance and are useful in building equipment for the chemical industry.
Wilhelm, H.A.; Ames, D.P.
Entropy generation minimization of a heat and mass exchanger for use in a humidification-dehumidification desalination system
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 ...
Thiel, Gregory P
New concept for quantification of similarity relates entropy and energy of objects: First and Second Law entangled, equivalence of temperature and time proposed
When the difference between changes in energy and entropy at a given temperature is correlated with the ratio between the same changes in energy and entropy at zero average free energy of an ensemble of similar but distinct molecule-sized objects, a highly significant linear dependence results from which a relationship between energy and entropy is derived and the degree of similarity between the distinctly different members within the group of objects can be quantified. This fundamental energy-entropy relationship is likely to be of general interest in physics, most notably in particle physics and cosmology. We predict a consistent and testable way of classifying mini black holes, to be generated in future Large Hadron Collider experiments, by their gravitational energy and area entropy. For any isolated universe we propose absolute temperature and absolute time to be equivalent, much in the same way as energy and entropy are for an isolated ensemble of similar objects. According to this principle, the cosmo...
Zimak, Petr; Strazewski, Peter
Benefits of rapid solidification processing of modified LaNi{sub 5} alloys by high pressure gas atomization for battery applications
A high pressure gas atomization approach to rapid solidification has been employed to investigate simplified processing of Sn modified LaNi{sub 5} powders that can be used for advanced Ni/metal hydride (Ni/MH) batteries. The current industrial practice involves casting large ingots followed by annealing and grinding and utilizes a complex and costly alloy design. This investigation is an attempt to produce powders for battery cathode fabrication that can be used in an as-atomized condition without annealing or grinding. Both Ar and He atomization gas were tried to investigate rapid solidification effects. Sn alloy additions were tested to promote subambient pressure absorption/desorption of hydrogen at ambient temperature. The resulting fine, spherical powders were subject to microstructural analysis, hydrogen gas cycling, and annealing experiments to evaluate suitability for Ni/MH battery applications. The results demonstrate that a brief anneal is required to homogenize the as-solidified microstructure of both Ar and He atomized powders and to achieve a suitable hydrogen absorption behavior. The Sn addition also appears to suppress cracking during hydrogen gas phase cycling in particles smaller than about 25 {micro}m. These results suggest that direct powder processing of a LaNi{sub 5{minus}x}Sn{sub x} alloy has potential application in rechargeable Ni/MH batteries.
Anderson, I.E.; Pecharsky, V.K.; Ting, J. [Ames Lab., IA (United States); Witham, C.; Bowman, R.C. [California Inst. of Tech., Pasadena, CA (United States)
Entropy signature of the running cosmological constant
Renormalization group (RG) improved cosmologies based upon a RG trajectory of Quantum Einstein Gravity (QEG) with realistic parameter values are investigated using a system of cosmological evolution equations which allows for an unrestricted energy exchange between the vacuum and the matter sector. It is demonstrated that the scale dependence of the gravitational parameters, the cosmological constant in particular, leads to an entropy production in the matter system. The picture emerges that the Universe started out from a state of vanishing entropy, and that the radiation entropy observed today is essentially due to the coarse graining (RG flow) in the quantum gravity sector which is related to the expansion of the Universe. Furthermore, the RG improved field equations are shown to possess solutions with an epoch of power law inflation immediately after the initial singularity. The inflation is driven by the cosmological constant and ends automatically once the RG running has reduced the vacuum energy to the...
Bonanno, Alfio
How to interpret black hole entropy?
We consider a possibility that the entropy of a Schwarzschild black hole has two different interpretations: The black hole entropy can be understood either as an outcome of a huge degeneracy in the mass eigenstates of the hole, or as a consequence of the fact that the interior region of black hole spacetime is separated from the exterior region by a horizon. In the latter case, no degeneracy in the mass eigenstates needs to be assumed. Our investigation is based on calculations performed with Lorentzian partition functions obtained for a whole maximally extended Schwarzschild spacetime, and for its right-hand-side exterior region. To check the correctness of our analysis we reproduce, in the leading order approximation, the Bekenstein--Hawking entropy of the Schwarzschild black hole.
J. Makela; P. Repo
On relation between emotion and entropy
The ways of modelling some of the most profound effects of emotion and arousal on cognition are discussed. Entropy reduction is used to measure quantitatively the learning speed in a cognitive model under different parameters ' conditions. It is noticed that some settings facilitate the learning in particular stages of problem solving more than others. The entropy feedback is used to control these parameters and strategy, which in turn improves greatly the learning in the model as well as the model match with the data. This result may explain the reasons behind some of the neurobiological changes, associated with emotion and its control of the decision making strategy and behaviour. 1
Roman V. Belavkin
Phonon densities of states of face-centered-cubic Ni-Fe alloys
Inelastic neutron scattering and nuclear resonant inelastic x-ray scattering were used to determine the phonon densities of states of face-centered-cubic Ni-Fe alloys. Increasing Fe concentration results in an average softening of the phonon modes. Chemical ordering of the Ni0.72Fe0.28 alloy results in a reduction of the partial vibrational entropy of the Fe atoms but does not significantly change the partial vibrational entropy of the Ni atoms. Changes in the phonon densities of states with composition and chemical ordering are discussed and analyzed with a cluster expansion method.
Lucas, Matthew [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Mauger, L [California Institute of Technology, W. M. Keck Laboratory, Pasadena] [California Institute of Technology, W. M. Keck Laboratory, Pasadena; Munoz, Jorge A. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Halevy, I [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Horwath, J [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Semiatin, S L [United States Air Force Research Laboratory, Wright-Patterson Air Force Base] [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Leontsev, S. O. [University of Kentucky, Lexington] [University of Kentucky, Lexington; Stone, Matthew B [ORNL] [ORNL; Abernathy, Douglas L [ORNL] [ORNL; Xiao, Yuming [Carnegie Institution of Washington] [Carnegie Institution of Washington; Chow, P [HPCAT Geophysical Lab, Argonne, IL] [HPCAT Geophysical Lab, Argonne, IL; Fultz, B. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena
Entropy Sources in Equilibrium Conditions over a Tropical Ocean
Confusion has existed as to sources of entropy due to irreversible processes in the atmosphere, the total of which matches the export of entropy by radiation. What is the mechanical efficiency of convection? For an ideal tropical oceanic system ...
Charles Warner
Smooth Renyi Entropies and the Quantum Information Spectrum
Many of the traditional results in information theory, such as the channel coding theorem or the source coding theorem, are restricted to scenarios where the underlying resources are independent and identically distributed (i.i.d.) over a large number of uses. To overcome this limitation, two different techniques, the information spectrum method and the smooth entropy framework, have been developed independently. They are based on new entropy measures, called spectral entropy rates and smooth entropies, respectively, that generalize Shannon entropy (in the classical case) and von Neumann entropy (in the more general quantum case). Here, we show that the two techniques are closely related. More precisely, the spectral entropy rate can be seen as the asymptotic limit of the smooth entropy. Our results apply to the quantum setting and thus include the classical setting as a special case.
Nilanjana Datta; Renato Renner
IMBALANCED RADIATION ENTROPY AND IMPLICATIONS FOR REMOTE SENSING Yangang Liu, Wei Wu and Warren and radiation entropy is needed to close the system. A new remote sensing approach is presented
Johnson, Peter D.
The Dry-Entropy Budget of a Moist Atmosphere
The entropy budget has been a popular starting point for theories of the work, or dissipation, performed by moist atmospheres. For a dry atmosphere, the entropy budget provides a theory for the dissipation in terms of the imposed diabatic heat ...
David M. Romps
High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005
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.
Guha, S.; Yang, J.
A new inequality for the von Neumann entropy
Strong subadditivity of von Neumann entropy, proved in 1973 by Lieb and Ruskai, is a cornerstone of quantum coding theory. All other known inequalities for entropies of quantum systems may be derived from it. Here we prove a new inequality for the von Neumann entropy which we prove is independent of strong subadditivity: it is an inequality which is true for any four party quantum state, provided that it satisfies three linear relations (constraints) on the entropies of certain reduced states.
Noah Linden; Andreas Winter
The preparation of low-melting-point plutonium alloys is described. In a MgO crucible Pu is placed on top of the lighter alloying metal (Fe, Co, or Ni) and the temperature raised to 1000 or 1200 deg C. Upon cooling, the alloy slug is broke out of the crucible. With 14 at. % Ni the m.p. is 465 deg C; with 9.5 at. % Fe the m.p. is 410 deg C; and with 12.0 at. % Co the m.p. is 405 deg C. (T.R.H.) l6262 l6263 ((((((((Abstract unscannable))))))))
Chynoweth, W.
Numerical Investigation of Wall Temperature and Entropy Layer Effects on Double Wedge Shock /
Numerical Investigation of Wall Temperature and Entropy Layer Effects on Double Wedge Shock of a strongly curved shock in front of the leading edge causing a layer of high-temperature and high the separation shock, reaching a plateau value which is only slightly affected by the increasing wall temperature
Chemical thermodynamics of nuclear materials. IX. High temperature heat capacity of plutonium-3. 2 at. % gallium alloy
The heat capacity of delta-stabilized plutonium (Pu - 3.2 at. % Ga) has been determined from 330 to 700/sup 0/K by an adiabatic calorimeter. The heat capacity for this alloy may be expressed by: Cp (Pu-3.2 at. % Ga)/(J K/sup -1/ mol/sup -1/) = 39.249 - 0.0264 (T/K) + 3.595 x 10/sup 5/ (T/K)/sup 2/ - 2.506 x 10/sup 5/ (K/T)/sup 2/. It was found that a large contribution to the heat capacity is due to the electronic heat capacity. The thermal functions for this plutonium-gallium alloy are calculated to 700/sup 0/K.
Adams, R.O.; Oetting, F.L.
A 2-Source Almost-Extractor for Linear Entropy
We give an explicit construction of a function that is almost a 2-source extractor for linear entropy, it is a condenser where the output has almost full entropy. Given 2 sources with entropy ďľżn, the output of the condenser ...
Anup Rao
A data streaming algorithm for estimating entropies of od flows
Entropy has recently gained considerable significance as an important metric for network measurement. Previous research has shown its utility in clustering traffic and detecting traffic anomalies. While measuring the entropy of the traffic observed at ... Keywords: data streaming, entropy estimation, network measurement, stable distributions, traffic matrix
Haiquan (Chuck) Zhao; Ashwin Lall; Mitsunori Ogihara; Oliver Spatscheck; Jia Wang; Jun Xu
Computer Simulation and Experimental Validation on the Oxidation and Sulfate Corrosion Resistance of Novel Chromium-Based High-temperature Alloys
Computer Simulation and Experimental Computer Simulation and Experimental Validation on the Oxidation and Sulfate Corrosion Resistance of Novel Chromium-Based High-temperature Alloys Background Advanced coal power generation is a critical component of the U.S. energy portfolio. The U.S. Department of Energy (DOE) is committed to supporting research that will increase the efficiency and decrease the environmental impact of coal-fired plants, thus enabling the long term use of a low cost domestic fuel source. One key factor to
Information entropy based methods for genome comparison
A plethora of biologically useful information lies obscured in the genomes of organisms. Encoded within the genome of an organism is the information about its evolutionary history. Evolutionary signals are scattered throughout the genome. Bioinformatics ... Keywords: clustering, genome comparison, segmentation, sequence alignment, shannon entropy
Mehul Jani; Rajeev K. Azad
Maximum Entropy Production in Climate Theory
R. D. Lorenz et al. claim that recent data on Mars and Titan show that planetary atmospheres are in unconstrained states of maximum entropy production (MEP). Their model as it applies to Venus, Earth, Mars, and Titan is reexamined, and it is ...
Richard Goody
Entanglement Entropy in Scalar Field Theory
Understanding the dependence of entanglement entropy on the renormalized mass in quantum field theories can provide insight into phenomena such as quantum phase transitions, since the mass varies in a singular way near the transition. Here we perturbatively calculate the entanglement entropy in interacting scalar field theory, focussing on the dependence on the field's mass. We study lambda phi^4 and g phi^3 theories in their ground state. By tracing over a half space, using the replica trick and position space Green's functions on the cone, we show that space-time volume divergences cancel and renormalization can be consistently performed in this conical geometry. We establish finite contributions to the entanglement entropy up to two-loop order, involving a finite area law. The resulting entropy is simple and intuitive: the free theory result in d=3 (that we included in an earlier publication) Delta S ~ A m^2 ln(m^2) is altered, to leading order, by replacing the bare mass m by the renormalized mass m_r eva...
Hertzberg, Mark P
Integrating Correlated Bayesian Networks Using Maximum Entropy
We consider the problem of generating a joint distribution for a pair of Bayesian networks that preserves the multivariate marginal distribution of each network and satisfies prescribed correlation between pairs of nodes taken from both networks. We derive the maximum entropy distribution for any pair of multivariate random vectors and prescribed correlations and demonstrate numerical results for an example integration of Bayesian networks.
Jarman, Kenneth D.; Whitney, Paul D.
A uranium alloy is reported containing from 0.1 to 5 per cent by weight of molybdenum and from 0.1 to 5 per cent by weight of silicon, the balance being uranium.
Colbeck, E.W.
A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)
Hydrogen in titanium alloys
The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500/sup 0/C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150/sup 0/C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement.
Wille, G.W.; Davis, J.W.
HIGH CREEP-STRENGTH ALLOYS P.J. Maziasz, J.P Shingledecker, R.W. Swindeman, R.L. Klueh and N.D. Evans
power plants [1-3]. While such alloys for boiler application must also be construction-code approved resistance in ultra- supercritical (USC) boiler conditions at 700o C and above [1,2]. This new alloy is also one of the candidate alloys being studied by the U.S. USC Boiler Consortium for steam temperatures
Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.
The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.
Dulikravich, George S.; Sikka, Vinod K.; Muralidharan, G.
Unusual Capacitance Emission Transients in CIGS Caused by Large Defect Entropy Changes
Capacitance transient data from bias-pulse experiments on CdS/CIGS solar cells show an unusual behavior at high temperatures. Above 350 K, a minority-carrier trap, with a larger activation energy than a majority-carrier trap, emits faster than the lower activation-energy minority trap. A simple enthalpy model for trap emission cannot explain this counterintuitive behavior; but the more complete Gibbs free-energy model that includes entropy can explain it. We show that entropy plays a major role in carrier emission from traps in CIGS.
Young, D. L.; Ramanathan, K.; Crandall, R. S.
Phase transformations in the Zn-Al eutectoid alloy after quenching from the high temperature triclinic beta phase
Ribbons of the Zn-Al eutectoid alloy obtained by melt-spinning, were heat treated at 350 deg. C during 30 min in a free atmosphere furnace, and then quenched in liquid nitrogen. The temperature correspond to {beta} phase zone, which has a triclinic crystalline structure [1, 2]. Some evidence, obtained by X-ray diffraction, show that the structures present in the just quenched material are both close-packed hexagonal ({eta}-phase) and rhombohedral (R-phase). X-ray diffractograms taken in the same ribbons after annealed 500 h at room temperature, show that the R phase its transform to {alpha} and {eta} phases.
Sandoval-Jimenez, A., E-mail: firstname.lastname@example.com [Instituto Nacional de Investigaciones Nucleares, Dpto. de Aceleradores, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Mexico, C.P. 52750, ESIME, Unidad Culhuacan, Dpto. Ing. Mecanica, IPN (Mexico); Negrete, J. [Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, SLP 78210 (Mexico); Torres-Villasenor, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-360, Mexico D.F. 04510 (Mexico)
Controlled Temperature Shape Rolling of Alloy 718
Incentive. Program (IMIP) to develop a bar mill for high temperature alloys .... and energy can be saved and that tool life ... enough to achieve steady-state.
Mechanical Behavior of Bulk Nanocrystalline Copper Alloys ...
Presentation Title, Mechanical Behavior of Bulk Nanocrystalline Copper Alloys Produced by High Energy Ball Milling. Author(s), Hamed Bahmanpour, Khaled M.
Alumina-forming Austenitic Alloys Licensed | ORNL
for alumina scales to form on the exterior of the steel, which provides significant oxidation resistance. In addition, the alloy displays excellent creep strength at high...
Li-Mg Solid Solution Alloy for Reversible Hydrogen Storage
Symposium, Hydrogen Storage in Materials: Theory and Experiment ... processes such as rapid solidification and high energy mechanical alloying. The results ...
Statistical entropy of the Schwarzschild black hole
We derive the statistical entropy of the Schwarzschild black hole by considering the asymptotic symmetry algebra near the $\\cal{I^{-}}$ boundary of the spacetime at past null infinity. Using a two-dimensional description and the Weyl invariance of black hole thermodynamics this symmetry algebra can be mapped into the Virasoro algebra generating asymptotic symmetries of anti-de Sitter spacetime. Using lagrangian methods we identify the stress-energy tensor of the boundary conformal field theory and we calculate the central charge of the Virasoro algebra. The Bekenstein-Hawking result for the black hole entropy is regained using Cardy's formula. Our result strongly supports a non-local realization of the holographic principle
Mariano Cadoni
Entropy Production during Asymptotically Safe Inflation
The Asymptotic Safety scenario predicts that the deep ultraviolet of Quantum Einstein Gravity is governed by a nontrivial renormalization group fixed point. Analyzing its implications for cosmology using renormalization group improved Einstein equations we find that it can give rise to a phase of inflationary expansion in the early Universe. Inflation is a pure quantum effect here and requires no inflaton field. It is driven by the cosmological constant and ends automatically when the renormalization group evolution has reduced the vacuum energy to the level of the matter energy density. The quantum gravity effects also provide a natural mechanism for the generation of entropy. It could easily account for the entire entropy of the present Universe in the massless sector.
Discontinuities in the Maximum-Entropy Inference
We revisit the maximum-entropy inference of the state of a finite-level quantum system under linear constraints. The constraints are specified by the expected values of a set of fixed observables. We point out the existence of discontinuities in this inference method. This is a pure quantum phenomenon since the maximum-entropy inference is continuous for mutually commuting observables. The question arises why some sets of observables are distinguished by a discontinuity in an inference method which is still discussed as a universal inference method. In this paper we make an example of a discontinuity and we explain a characterization of the discontinuities in terms of the openness of the (restricted) linear map that assigns expected values to states.
Stephan Weis
A Fast Hybrid Decision Algorithm for H.264/AVC Intra Prediction Based on Entropy Theory
Rate Distortion Optimization based spatial intra coding is a new feature of H.264/AVC standard. It efficiently improves the video coding performance by brutally utilizing variable block sizes and multiple prediction modes. Thus, extremely high computation ... Keywords: Block Size Decision, Entropy Theory, H.264/AVC, Intra Prediction, Mode Decision
Guifen Tian; Tianruo Zhang; Takeshi Ikenaga; Satoshi Goto
Entropy driven multi-photon frequency up-conversion
Frequency up-conversion of few low-energy photons into a single high-energy photon, greatly contributes to imaging, light sources, detection and other fields of research. However, it offers negligible efficiency when up-converting many photons. This is because coherent process are fundamentally limited due to momentum conservation requirements, while in incoherent up-conversion the finite intermediate states lifetime requires huge intensities. Thermodynamically, conventional incoherent up-conversion is driven by the internal energy of the incoming photons. However, a system can also drive work through change in its collective properties such as entropy. Here we experimentally demonstrate entropy driven ten-fold up-conversion from 10.6{\\mu} to 1{\\mu}m at internal efficiency above 27% and total efficiency above 10%. In addition, the emitted radiance at 1{\\mu}m exceeds the maximal possible Black-Body radiance of our device, indicating emitter's effective-temperature that is considerably above the bulk-temperatur...
Manor, Assaf; Rotschild, Carmel
Alloy nanoparticle synthesis using ionizing radiation
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.
Nenoff, Tina M. (Sandia Park, NM); Powers, Dana A. (Albuquerque, NM); Zhang, Zhenyuan (Durham, NC)
Status of Testing and Characterization of CMS Alloy 617 and Alloy 230
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.
Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)
Passive Corrosion Behavior of Alloy 22
Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.
R.B. Rebak; J.H. Payer
The Importance of the Entropy Inequality on Numerical Simulations Using Reduced Methane-air Reaction Mechanisms
Many reaction mechanisms have been developed over the past few decades to predict flame characteristics. A detailed reaction mechanism can predict flame characteristics well, but at a high computational cost. The reason for reducing reaction mechanisms is to reduce the computational time needed to simulate a problem. The focus of this work is on the validity of reduced methane-air combustion mechanisms, particularly pertaining to satisfying the entropy inequality. While much of this work involves a two-step reaction mechanism developed by Dr. Charles Westbrook and Dr. Frederick Dryer, some consideration is given to the four-step and three-step mechanisms of Dr. Norbert Peters. These mechanisms are used to simulate the Flame A experiment from Sandia National Laboratories. The two-step mechanism of Westbrook and Dryer is found to generate results that violate the entropy inequality. Modifications are made to the two-step mechanism simulation in an effort to reduce these violations. Two new mechanisms, Mech 1 and Mech 2, are developed from the original two-step reaction mechanism by modifying the empirical data constants in the Arrhenius reaction form. The reaction exponents are set to the stoichiometric coefficients of the reaction, and the concentrations computed from a one-dimensional flame simulation are matched by changing the Arrhenius parameters. The new mechanisms match experimental data more closely than the original two-step mechanism and result in a significant reduction in entropy inequality violations. The solution from Mech 1 had only 9 cells that violated the entropy inequality, while the original two-step mechanism of Westbrook and Dryer had 22,016 cells that violated the entropy inequality. The solution from Mech 2 did not have entropy inequality violations. The method used herein for developing the new mechanisms can be applied to more complex reaction mechanisms.
Jones, Nathan
Fracture Toughness Characterization of 304L and 316L and Alloy 718 After Irradiation in High-Energy, Mixed Proton/Neutron Spectrum
This paper describes the fracture toughness characterization of annealed 304L and 316L stainless steels and precipitation hardened Alloy 718, performed at the Oak Ridge National Laboratory as a part of the experimental design and development for the Accelerator Production of Tritium (APT) target/blanket system. Materials were irradiated at 25 to 200 C by high-energy protons and neutrons from an 800-MeV, 1-mA proton beam at the Los Alamos Neutron Science Center (LANSCE). The proton flux produced in LANSCE is nearly prototypic of anticipated conditions for significant portions of the APT target/blanket system. The objective of this testing program was to determine the change in crack-extension resistance of candidate APT materials from irradiation at prototypic APT temperatures and proton and neutron fluxes. J-integral-resistance (J-R) curve toughness tests were conducted in general accordance with the American Society for Testing and Materials Standard Test Method for Measurement of Fracture Toughness, E 1820-99, with a computer-controlled test and data acquisition system. J-R curves were obtained from subsize disk-shaped compact tension specimens (12.5 mm in diameter) with thicknesses of 4 mm or 2 mm. Irradiation up to 12 dpa significantly reduced the fracture toughness of these materials. Alloy 718 had the lowest fracture toughness in both the unirradiated and irradiated conditions. All irradiated specimens of Alloy 718 failed by sudden unstable crack extension regardless of dose or test temperature. Type 304L and 316L stainless steels had a high level of fracture toughness in the unirradiated condition and exhibited reduction in fracture toughness to saturation levels of 65 to 100 MPa{radical}m. The present reduction in fracture toughness is similar to changes reported from fission reactor studies. However, the currently observed losses in toughness appear to saturate at doses slightly lower than the dose required for saturation in reactor-irradiated steels. This difference might be attributed to the increased helium and hydrogen production associated with irradiation in the high-energy, mixed proton/neutron spectrum.
Sokolov, M.A.
Electrical Conduction, Heat Conduction, Shear Viscosity and Entropy
We present here how to study steady linear transport phenomena by using entropy. We study the system and the environment together and identify their entropies. Concerning their interaction, quantum mechanics is considered. A time parameter $\\tau$ is therefore introduced to characterize the discrete nature of the quantum interactions. By combining $\\tau$ and the entropy, an approach is constructed successfully to study electrical conduction, heat conduction and shear viscosity
Zhang, Yong-Jun
Holographic Entanglement Entropy for 4D Conformal Gravity
Using the proposal for holographic entanglement entropy in higher derivative gravities, we compute holographic entanglement entropy for the conformal gravity in four dimensions which turns out to be finite. However, if one subtracts the contribution of the four dimensional Gauss-Bonnet term, the corresponding entanglement entropy has a divergent term and indeed restricted to an Einstein solution of the conformal gravity, the resultant entanglement entropy is exactly the same as that in the Einstein gravity. We will also make a comment on the first law of the entanglement thermodynamics for the conformal gravity in four dimensions.
Mohsen Alishahiha; Amin Faraji Astaneh; M. Reza Mohammadi Mozaffar
Microscopic diagonal entropy and its connection to basic thermodynamic relations
We define a diagonal entropy (d-entropy) for an arbitrary Hamiltonian system as S{sub d}=-{Sigma}{sub n{rho}nn}ln{rho}{sub nn} with the sum taken over the basis of instantaneous energy states. In equilibrium this entropy coincides with the conventional von Neumann entropy S{sub n} = -Tr{rho} ln {rho}. However, in contrast to S{sub n}, the d-entropy is not conserved in time in closed Hamiltonian systems. If the system is initially in stationary state then in accord with the second law of thermodynamics the d-entropy can only increase or stay the same. We also show that the d-entropy can be expressed through the energy distribution function and thus it is measurable, at least in principle. Under very generic assumptions of the locality of the Hamiltonian and non-integrability the d-entropy becomes a unique function of the average energy in large systems and automatically satisfies the fundamental thermodynamic relation. This relation reduces to the first law of thermodynamics for quasi-static processes. The d-entropy is also automatically conserved for adiabatic processes. We illustrate our results with explicit examples and show that S{sub d} behaves consistently with expectations from thermodynamics.
Polkovnikov, Anatoli, E-mail: firstname.lastname@example.com [Department of Physics, Boston University, Boston, MA 02215 (United States)
2 Renyi's Entropy, Divergence and Their Nonparametric Estimators
Then a new estimator for Renyi's quadratic entropy is developed using kernel density estimation. With cost functions for adapta- tion in mind, the properties of ...
Casimir energy and entropy in the sphere-sphere geometry
We calculate the Casimir energy and entropy for two spheres described by the perfect-metal model, plasma model, and Drude model in the large-separation limit. We obtain nonmonotonic behavior of the Helmholtz free energy as a function of separation and temperature for the perfect-metal and plasma models, leading to parameter ranges with negative entropy, and also we obtain nonmonotonic behavior of the entropy as a function of temperature and the separation between the spheres. This nonmonotonic behavior has not been found for the Drude model. The appearance of this anomalous behavior of the entropy as well as its thermodynamic consequences are discussed.
Rodriguez-Lopez, Pablo [Departamento de Fisica Aplicada I and GISC, Facultad de Ciencias Fisicas, Universidad Complutense, ES-28040 Madrid (Spain)
Mutual Entropy in Quantum Information and Information Genetics
After Shannon, entropy becomes a fundamental quantity to describe not only uncertainity or chaos of a system but also information carried by the system. Shannon's important discovery is to give a mathematical expression of the mutual entropy (information), information transmitted from an input system to an output system, by which communication processes could be analyzed on the stage of mathematical science. In this paper, first we review the quantum mutual entropy and discuss its uses in quantum information theory, and secondly we show how the classical mutual entropy can be used to analyze genomes, in particular, those of HIV.
Masanori Ohya
Moderate Degree of Input Negative Entropy Flow and Decrease of Entropy in Astrophysics, Biology, Psychology and Social Systems
Thermodynamics have been applied to astronomy, biology, psychology, some social systems and so on. But, various evolutions from astronomy to biology and social systems cannot be only increase of entropy. When fluctuations are magnified due to internal interactions, the statistical independence and the second law of the thermodynamics are not hold. The existence of internal interactions is necessary condition of decrease of entropy in isolated system. We calculate quantitatively the entropy of plasma. Then we discuss the thermodynamics of biology, and obtain a mathematical expression on moderate degree of input negative entropy flow, which is a universal scientific law. Further, the thermodynamics of physiology and psychology, and the thought field are introduced. Qigong and various religious practices are related to these states of order, in which decrease of entropy is shown due to internal interactions of the isolated systems. Finally we discuss possible decrease of entropy in some social systems.
Black Hole Radiation and Volume Statistical Entropy
The simplest possible equation for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius which is similar to the Compton wavelength relation.
Mario Rabinowitz
Characterization of High Strain Rate Mechanical behavior of AZ31 magnesium alloy using 3D Digital Image Correlation
Characterization of the material mechanical behavior at sub-Hopkinson regime (0.1 to 1000 s{sup -1}) is very challenging due to instrumentation limitations and the complexity of data analysis involved in dynamic loading. In this study, AZ31 magnesium alloy sheet specimens are tested using a custom designed servo-hydraulic machine in tension at nominal strain rates up to 1000 s{sup -1}. In order to resolve strain measurement artifacts, the specimen displacement is measured using 3D Digital Image correlation instead from actuator motion. The total strain is measured up to {approx} 30%, which is far beyond the measurable range of electric resistance strain gages. Stresses are calculated based on the elastic strains in the tab of a standard dog-bone shaped specimen. Using this technique, the stresses measured for strain rates of 100 s{sup -1} and lower show little or no noise comparing to load cell signals. When the strain rates are higher than 250 s{sup -1}, the noises and oscillations in the stress measurements are significantly decreased from {approx} 250 to 50 MPa. Overall, it is found that there are no significant differences in the elongation, although the material exhibits slight work hardening when the strain rate is increased from 1 to 100 s{sup -1}.
Wang, Yanli [ORNL; Xu, Hanbing [ORNL; ERDMAN III, DONALD L [ORNL; Starbuck, J Michael [ORNL; Simunovic, Srdjan [ORNL
Tritium Production from Palladium Alloys
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.
Claytor, T.N.; Schwab, M.J.; Thoma, D.J.; Teter, D.F.; Tuggle, D.G.
Discretization of continuous ECG based risk metrics using asymmetric and warped entropy measures
We investigate several entropy based approaches to finding cut points for discretizing continuous ECG-based risk metrics. We describe two existing approaches, Shannon entropy and asymmetric entropy, and one new approach, ...
Singh, Anima
An Equation for Moist Entropy in a Precipitating and Icy Atmosphere
This paper addresses an equation for moist entropy in the framework of cloud-resolving models. After rewriting the energy equation with moist entropy in the place of temperature, an equation for moist entropy is obtained. The equation expresses ...
Xiping Zeng; Wei-Kuo Tao; Joanne Simpson
Entropy of Chaotic Oscillations of Currents in the Chua Circuit and its HMM Analysis
We study entropy of chaotic oscillation of electrical currents in the Chua's circuit controlled by triggering a pulse that brings the orbit that goes onto an unstable branch back to a stable branch. A numerical simulation of the voltage of the two capacitors and the current that flows on an inductor of the Chua's circuit reveals various oscillation patterns as the conductance that is connected between the two capacitors and directly connected to an inductor is varied. At small conductance, the Lissajous graph of the voltage of the two capacitors shows a spiral, while at high conductance a double scroll pattern appears. The entropy of the current that flows on the inductor is alocal minimum in the spiral state which is in the steady state, while it is maximum in the stable double scroll state. The stable double scroll samples are analyzed by using the Hidden Markov Model (HMM) and the eigenvectors of the transition matrix of long time series are found to be strictly positive but those of unstable short time series have negative components. We thus confirm maximum entropy production in the double scroll of the longest time series around the right fixed point, while the local minimum entropy production occurs in the spiral around the left fixed point.
Sadataka Furui
Temporal Entropy Generation in the Viscous Layers of Laterally-converging Duct Flows
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.
Donald M. McEligot; Robert S. Brodkey; Helmut Eckelmann
Intracluster and Intragroup Entropy from Quasar Activity
We investigate how the hierarchical merging of dark matter halos, the radiative cooling of baryons, and the energy feedback from supernovae and active galactic nuclei or quasars combine to govern the amount and the thermal state of the hot plasma pervading groups and clusters of galaxies. We show that, by itself, supernova preheating of the external gas flowing into clusters falls short of explaining the observed X-ray scaling relations of the plasma luminosity L_X or the plasma entropy K versus the X-ray temperature T. To account for the scaling laws from rich to poor clusters takes preheating enhanced by the energy input from active galactic nuclei. In groups, on the other hand, the internal impacts of powerful quasars going off in member galaxies can blow some plasma out of the structure. So they depress L_X and raise K to the observed average levels; meanwhile, the sporadic nature of such impulsive events generates the intrinsic component of the wide scatter apparent in the data. The same quasar feedback gives rise in groups to entropy profiles as steep as observed, a feature hard to explain with simple preheating schemes. Finally, we argue a close connection of the L_X-T or the K-T relation with the M_{\\bullet}-\\sigma correlation between the host velocity dispersion and the masses of the black holes, relics of the quasar activity.
A. Lapi; A. Cavaliere; N. Menci
The continuity of the output entropy of positive maps
Global and local continuity conditions for the output von Neumann entropy for positive maps between Banach spaces of trace-class operators in separable Hilbert spaces are obtained. Special attention is paid to completely positive maps: infinite dimensional quantum channels and operations. It is shown that as a result of some specific properties of the von Neumann entropy (as a function on the set of density operators) several results on the output entropy of positive maps can be obtained, which cannot be derived from the general properties of entropy type functions. In particular, it is proved that global continuity of the output entropy of a positive map follows from its finiteness. A characterization of positive linear maps preserving continuity of the entropy (in the following sense: continuity of the entropy on an arbitrary subset of input operators implies continuity of the output entropy on this subset) is obtained. A connection between the local continuity properties of two completely positive complementary maps is considered. Bibliography: 21 titles.
Shirokov, Maxim E [Steklov Mathematical Institute, Russian Academy of Sciences, Moscow (Russian Federation)
Positive and negative entropy production in thermodynamic systems
This article presents a heuristic combination of the local and global formulations of the second law of thermodynamics that suggests the possibility of theoretical existence of thermodynamic processes with positive and negative entropy production.Such processes may exhibit entropy couplings that reveal an unusual behavior from the point of view of conventional thermodynamics.
Belandria, Jose Iraides
Surface alloying of silicon into aluminum substrate.
Aluminum alloys that are easily castable tend to have lower silicon content and hence lower wear resistance. The use of laser surface alloying to improve the surface wear resistance of 319 and 320 aluminum alloys was examined. A silicon layer was painted onto the surface to be treated. A high power pulsed Nd:YAG laser with fiberoptic beam delivery was used to carry out the laser surface treatment to enhance the silicon content. Process parameters were varied to minimize the surface roughness from overlap of the laser beam treatment. The surface-alloyed layer was characterized and the silicon content was determined.
Xu, Z.
Effect of aluminizing of Cr-containing ferritic alloys on the seal strength of a novel high-temperature solid oxide fuel cell sealing glass
A novel high-temperature alkaline-earth silicate sealing glass was developed for solid oxide fuel cell (SOFC) applications. The glass was used to join two metallic coupons of Cr-containing ferritic stainless steel for seal strength evaluation. In previous work, SrCrO4 was found to form along the glass/steel interface, which led to severe strength degradation. In the present study, aluminization of the steel surface was investigated as a remedy to minimize or prevent the strontium chromate formation. Three different processes for aluminization were evaluated with Crofer22APU stainless steel: pack cementation, vapor phase deposition, and aerosol spraying. It was found that pack cementation resulted in a rough surface with occasional cracks in the Al-diffused region. Vapor phase deposition yielded a smoother surface, but the resulting high Al content increased the coefficient of thermal expansion (CTE), resulting in failure of joined coupons. Aerosol spraying of an Al-containing salt resulted in formation of a thin aluminum oxide layer without any surface damage. The room temperature seal strength was evaluated in the as-fired state and in environmentally aged conditions. In contrast to earlier results with uncoated Crofer22APU, the aluminized samples showed no strength degradation even for samples aged in air. Interfacial and chemical compatibility was also investigated. The results showed aluminization to be a viable candidate approach to minimize undesirable chromate formation between alkaline earth silicate sealing glass and Cr-containing interconnect alloys for SOFC applications.
Chou, Y. S.; Stevenson, Jeffry W.; Singh, Prabhakar
Metal alloy identifier
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.
Riley, William D. (Avondale, MD); Brown, Jr., Robert D. (Avondale, MD)
High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium
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.
Lechtenberg, T.A.; Stevenson, R.D.; Johnson, W.R.
Hardfacing with cobalt and nickel alloys
The use of cobalt or nickel alloys for added wear resistance was initiated in the early 1900s with the development of the cobalt-chromium-tungsten family of alloys. The cobalt alloys were called the Stellite'' because of their bright, shiny, nontarnished appearance. Further development and characterization of this alloy system established its usage in unlubricated metal-to-metal contact or erosion by high-velocity fluid or solid particulate impingement. Initially, the alloys were used as solid castings but later were applied by welding to tougher or more ductile substrates, hence the birth of the hardfacing industry. Many of the original Stellite compositions are still in use, but many others, including the nickel and iron alloys, have been developed for special applications or for use by newer application procedures. Examining the microstructural features and wear properties of these families of hardfacing alloys can help in choosing the right alloy for the job. Various cobalt and nickel alloys, their available product forms and the corresponding hardfacing methods, are reviewed in this article.
Wu, J.B.C. (Stoody Deloro Stellite, Inc., St. Louis, MO (United States)); Redman, J. (Redman (James), Los Angles, CA (United States))
Infinitely many constrained inequalities for the von Neumann entropy
We exhibit infinitely many new, constrained inequalities for the von Neumann entropy, and show that they are independent of each other and the known inequalities obeyed by the von Neumann entropy (basically strong subadditivity). The new inequalities were proved originally by Makarychev et al. [Commun. Inf. Syst., 2(2):147-166, 2002] for the Shannon entropy, using properties of probability distributions. Our approach extends the proof of the inequalities to the quantum domain, and includes their independence for the quantum and also the classical cases.
Josh Cadney; Noah Linden; Andreas Winter
Induced gravity and entanglement entropy of 2D black holes
Using the fact that 2D Newton constant is wholly induced by a conformal field theory, we derive a formula for the entanglement entropy of the anti-de Sitter black hole in two spacetime dimensions. The leading term in the large black hole mass expansion of our formula reproduces exactly the Bekenstein-Hawking entropy S_{BH}, whereas the subleading term behaves as ln S_{BH}. This subleading term has the universal form typical for the entanglement entropy of physical systems described by effective conformal fields theories (e.g. one-dimensional statistical models at the critical point).
Welding and Repair Technology Center: Evaluation of High-Chromium Nickel-Base Welding Alloys, Resistance to Solidification Cracking - Update
One of the challenges faced by nuclear power industry engineers and managers responsible for making welding and repair decisions is selection of weld metals that have adequate resistance to stress corrosion cracking (SCC) with acceptable resistance to other forms of cracking. Continued testing and evaluation of new and enhanced high-chromium nickel-base filler metals is important to understanding the influence of slight composition changes on sensitivity to known cracking mechanisms and general ...
Triple Ion-Beam Studies of Radiation Damage Effects in a 316LN Austenitic Alloy for a High Power Spallation Neutron Source
Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe{sup 2}, 360 keV He{sup +}, and 180 keV H{sup +} to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of {approx} 1 {micro}m. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss.
Lee, EH
On the inverse problem of entropy maximizations (Corresp.)
The inverse isoperimetric problem of the entropy functional is considered in this Correspondence. This problem can be stated as follows: Given a known probability density function (pdf), what prior constraints are needed in order for this pdf to be the ...
J. Noonan; N. Tzannes; T. Costello
On the Relationship between Radiative Entropy and Temperature Distributions
The Earth can be viewed as a complex nonequilibrium system that exchanges primarily radiative energy and entropy with its surroundings. The energy balance equation provides an important constraint on the distribution of outgoing radiation since ...
Glen B. Lesins
Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal (i.e. referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss ...
A Remark on the Strict Positivity of the Entropy Production
We establish an algebraic criterion which ensures the strict positivity of the entropy production in quantum models consisting of a small system coupled to thermal reservoirs at different temperatures.
Walter H. Aschbacher; Herbert Spohn
Entropy production for mechanically or chemically driven biomolecules
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.
Tim Schmiedl; Thomas Speck; Udo Seifert
A new entropy based method for computing software structural complexity
In this paper a new methodology for the evaluation of software structural complexity is described. It is based on the entropy evaluation of the random uniform response function associated with the so called software characteristic function SCF. The behavior of the SCF with the different software structures and their relationship with the number of inherent errors is investigated. It is also investigated how the entropy concept can be used to evaluate the complexity of a software structure considering the SCF as a canonical representation of the graph associated with the control flow diagram. The functions, parameters and algorithms that allow to carry out this evaluation are also introduced. After this analytic phase follows the experimental phase, verifying the consistency of the proposed metric and their boundary conditions. The conclusion is that the degree of software structural complexity can be measured as the entropy of the random uniform response function of the SCF. That entropy is in direct relation...
Roca, J L
Evaluating Ontology Modules Using an Entropy Inspired Metric
The focus of ontology modularization to date has largely been on the creation of techniques to carry out ontology modularization. This creates a problem in evaluating the results of the different techniques. Ontology modularization techniques cannot ... Keywords: Ontology modularization, entropy
Paul Doran; Valentina Tamma; Ignazio Palmisano; Terry R. Payne; Luigi Iannone
Entropy Generation In the Ocean by Small-Scale Mixing
An expression that includes salt diffusion was developed and evaluated for the rate of entropy production ? in the ocean. The evaluation was done for mixing events produced by turbulent overturns and double diffusion. Temperature and salinity ...
M. C. Gregg
Humidity Profile Retrieval Using a Maximum Entropy Principle
A satellite data inversion method based on a maximum entropy principle is presented. The method is both physical since a radiative transfer model with its adjoint is needed, and also statistical since errors of the observed radiances and of a ...
Bernard Urban
Entropy production at freeze-out from dissipative fluids
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.
E. Molnar
Entropy of 2D black holes from counting microstates
We present a microscopical derivation of the entropy of the black hole solutions of the Jackiw-Teitelboim theory. We show that the asymptotic symmetry of two-dimensional (2D) Anti-de Sitter space is generated by a central extension of the Virasoro algebra. Using a canonical realization of this symmetry and Cardy's formula we calculate the statistical entropy of 2D black holes, which turns out to agree, up to a factor $\\sqrt 2$, with the thermodynamical result.
Mariano Cadoni; Salvatore Mignemi
Unification of Maximum Entropy and Bayesian Inference via Plausible Reasoning
This paper modifies Jaynes's axioms of plausible reasoning and derives the minimum relative entropy principle as well as Bayes's rule from first principles. The new axioms, which I call the Optimum Information Principle, is applicable whenever the decision maker is given the data and the relevant background information. Given that the maximum entropy principle and Bayesian inference are useful methods, the Optimum Information Principle is at least as useful.
Toda, Alexis Akira
The Monotonicity of the Gravitational Entropy Scalar within Quiescent Cosmology
In this paper we show that Quiescent Cosmology [1, 2, 3] is consistent with Penrose's Weyl Curvature Hypothesis and the notion of gravitational entropy [4]. Gravitational entropy, from a conceptual point of view, acts in an opposite fashion to the more familiar notion of entropy. A closed system of gravitating particles will coalesce whereas a collection of gas particles will tend to diffuse; regarding increasing entropy, these two scenarios are identical. What has been shown previously [2, 3] is that gravitational entropy at the initial singularity predicted by Quiescent Cosmology - the Isotropic Past Singularity (IPS) - tends to zero. The results from this paper show that not only is this the case but that gravitational entropy increases as this singularity evolves. In the first section of this paper we present relevant background information and motivation. In the second section of this paper we present the main results of this paper. Our third section contains a discussion of how this result will inspire future research before we make concluding remarks in our final section.
Philip Threlfall; Susan M. Scott
We investigate how the hierarchical merging of dark matter halos, the radiative cooling of baryons, and the energy feedback from supernovae and active galactic nuclei or quasars combine to govern the amount and the thermal state of the hot plasma pervading groups and clusters of galaxies. We show that by itself supernova preheating of the external gas flowing into clusters falls short of explaining the observed X-ray scaling relations of the plasma luminosity L_X or the plasma entropy K vs. the X-ray temperature T. To account for the scaling laws from rich to poor clusters it takes preheating enhanced by the energy input from active galactic nuclei. In groups, on the other hand, the internal impacts of powerful quasars going off in member galaxies can blow some plasma out of the structure. So they depress L_X and raise K to the observed average levels; meanwhile, the sporadic nature of such impulsive events generates the intrinsic component of the wide scatter apparent in the data. The same quasar feedback gi...
Lapi, A; Menci, N
Refractory Alloy Welding [Laser Applications Laboratory] - Nuclear
Refractory Alloy Welding Refractory Alloy Welding Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Refractory Alloy Welding Project description: Welding of refractory metals such as vanadium alloys. Category: internal R&D project Bookmark and Share Butt weld of two 4 mm thick V-4Cr-4Ti plates made by a pulsed Nd:YAG laser
Improved Martensitic Steel for High Temperature Applications
NETL has developed a stainless steel composition and heat treatment process for a high-temperature, titanium alloyed 9 Cr-1 molybdenum alloy ...
"Electroless" E-Coating for Mg Alloys
... be a cost-effective surface preparation/treatment process for the "electroless" ... High-Capacity Hydrogen-Based Green-Energy Storage Solutions for the Grid Balancing ... K-22: Insights into the Nucleation of Extension Twins in Mg Alloys.
Corrosion fatigue crack growth in clad low-alloy steel. Part 2, Water flow rate effects in high sulfur plate steel
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.
James, L.A; Lee, H.B.; Wire, G.L.; Novak, S.R. [Bettis Atomic Power Lab., West Mifflin, PA (United States); Cullen, W.H. [Materials Engineering Associates, Inc., Lanham, MD (United States)
Production of Copper Alloy Sheet by Twin-roll Casting
K2: Microstructural Development of Plutonium Alloys via Cooling Curve Analysis · K3: Preparation of High Purity Tellurium by Zone Refining Process.
Through-process Modeling for Cold Spray Alloy Optimization
Presentation Title, Through-process Modeling for Cold Spray Alloy Optimization ... repairability, and energy efficiency are highly desirable in many industries.
Recycling alloy for structural applications in the automotive industry
High Strength Aluminum Brazing Sheets for Condenser Fins of Automotive ... predictions for the phase formation in a wide range of commercial aluminum alloys.
Rene 220: 100 F Improvement Over Alloy 718
Through an unconventional approach, a successful alloy design project has been accom- plished to develop a weldable high-strength cast superalloy with ...
Compression Behavior and Energy Absorption of Aluminum Alloys ...
Presentation Title, Compression Behavior and Energy Absorption of ... Abstract Scope, The usage of advanced high strength steels and Aluminum Alloys as ...
Constitution Diagram for Dissimilar Metal Welds in Alloy Steels and ...
Explosive Bonding of 316L to C18150 CuCrZr Alloy for ITER Applications · Failure Mechanisms of Dissimilar Metal Welds During High Temperature Service.
Preparations of rare earth-iron alloys by thermite reduction
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.
Schmidt, Frederick A. (Ames, IA); Peterson, David T. (Ames, IA); Wheelock, John T. (Nevada, IA)
Qualms concerning Tsallis ' Use of the Maximum Entropy Formalism
Tsallis ' 'statistical thermodynamic ' formulation of the nonadditive entropy of degree-? is neither correct nor self-consistent. It is well known that the maximum entropy formalism [1], the minimum discrimination information [2], and Gauss ' principle [3, 4] all lead to the same results when a certain condition on the prior probability distribution is imposed [5]. All these methods lead to the same form of the posterior probability distribution; namely, the exponential family of distributions. Tsallis and collaborators [6] have tried to adapt the maximum entropy formalism that uses the Shannon entropy to one that uses a nonadditive entropy of degree-?. In order to come out with analytic expressions for the probabilities that maximize the nonadditive entropy they found it necessary to use 'escort probabilities'[7] of the same power as the nonadditive entropy. If the procedure they use is correct then it follows that Gauss ' principle should give the same optimum probabilities. Yet, we will find that the Tsallis result requires that the prior probability distribution be given by the same unphysical condition as the maximum entropy formalism and, what is worse, the potential of the error law be required to vanish. The potential of the error law is what information theory refers to as the error [8]; that is, the difference between the inaccuracy and the entropy. Unless the 'true ' probability distribution, P = (p(x1), p(x2)...,p(xm)) coincides with the estimated probability distribution, Q = (q(x1), q(x2),...q(xm)), the error does not vanish. Moreover, we shall show that two procedures of averaging, one using the escort probabilities explicitly, do not give the same result, and the relation between the potential of the error law and the nonadditive entropy requires the latter to vanish when the former vanishes. Let X be a random variable whose values x1, x2,..., xm are obtained at m independent trials. Prior to the observations the distribution is Q, and after the observations the unknown probability distribution is P. The observer has 1 at his disposal the statistic â = 1
B. H. Lavenda; J. Dunning-davies
Acceleration of ordering transformation of a new Fe{sub 2}(Mn,Cr)Si Heusler-alloy film by very high frequency plasma irradiation process during radio frequency sputter deposition
A new Heusler alloy, Fe{sub 2}(Mn,Cr)Si, that is likely to have high spin polarization (P) and high damping constant ({alpha}) was proposed to obtain high magneto-resistance ratio and low spin torque noise in a magnetic read head with a current-perpendicular-to-plane (CPP) giant magneto-resistance (GMR) multilayer. A very high frequency (VHF) plasma irradiation process during radio frequency (RF) sputter deposition was investigated to form the highly ordered structure of the Heusler alloy film with low thermal treatment temperature. The main results are as follows: (1) P and magnetic moment of Fe{sub 2}(Mn{sub 0.5}Cr{sub 0.5})Si with an L2{sub 1} structure were estimated at 0.99 and 2.49 {mu}{sub B}/f.u., respectively, and {alpha} was also estimated to be larger compared with the case of Co{sub 2}MnSi, according to density of states (DOS) calculations. (2) The ordering (at least B2 structure) temperature of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film decreased from 500 to 300 deg. C by using the VHF plasma irradiation process with optimized condition. (3) The surface roughness of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film also reduced from 1.7 to 0.5 nm by using the VHF plasma irradiation process. It is found that the Fe{sub 2}(Mn,Cr)Si Heusler alloy and the VHF plasma irradiation process with optimized condition seems to be applicable for fabrication of high-performance magnetic read head with CPP-GMR device.
Yoshimura, S.; Kobayashi, H.; Egawa, G.; Saito, H. [Center for Geo-environmental Science, Graduate School of Engineering and Resource Science, Akita University, Akita, 010-8502 (Japan); Ishida, S. [Department of Physics, Graduate School of Science and Engineering, Kagoshima University, Kagoshima, 890-8580 (Japan)
Program on Technology Innovation: Liquid Precursor High-Velocity Oxy-Fuel Spray Process for Making Fine Structured and Highly Bonded Alloy Coatings
High velocity oxygen-fuel (HVOF) thermal spray processes are used in applications requiring the highest density and adhesion strength, which is not achievable in most other thermal spray processes. Like other thermal spray processes, however, a normal HVOF process is not able to apply fine powders less than 10m via a conventional powder feeder like other thermal spray processes. The advantages of using smaller nano-sized particles in a HVOF process include uniform coating, uniform microstructure, higher ...
Delta-phase plutonium alloys were developed suitable for use as reactor fuels. The alloys consist of from 1 to 4 at.% zinc and the balance plutonium. The alloys have good neutronic, corrosion, and fabrication characteristics snd possess good dimensional characteristics throughout an operating temperature range from 300 to 490 deg C.
Cramer, E.M.; Ellinger, F.H.; Land. C.C.
New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.
Schonfeld, F.W.
A new vanadium-base alloy which possesses remarkable superconducting properties is presented. The alloy consists of approximately one atomic percent of palladium, the balance being vanadium. The alloy is stated to be useful in a cryotron in digital computer circuits.
Cleary, H.J.
Characterization of High Performance Alloys
Mar 6, 2013 ... The current methods investigated will supply information of local spacing ... were used to determine phase compositions and lattice parameters.
Thermodynamics and Structure of Plutonium Alloys
The goal of this project was to investigate the chemical and structural effects of gallium and impurity elements, iron and nickel, on the phase behavior and crystallography of Pu-Ga alloys. This was done utilizing a theoretical chemical approach to predict binary and ternary alloy energetics, phase stability, and transformations. The modeling results were validated with experimental data derived from the synthesis of selected alloys and advanced characterization tools. The ultimate goal of this work was to develop a robust predictive capability for studying the thermodynamics and the structure-properties relationships in complex materials of high relevance to the Laboratory and DOE mission.
Allen, P G; Turchi, P A; Gallegos, G F
Physical and Mechanical Properties of Copper and Copper Alloys
High strength, high conductivity copper alloys are prime candidates for high heat flux applications in fusion energy systems. This chapter reviews the physical and mechanical properties of pure copper and copper alloys with the focus on precipitation-hardened CuCrZr and dispersion-strengthened CuAl25 alloys. The effect of neutron irradiation on copper and copper alloys is reviewed in terms of radiation effects on physical properties and mechanical properties (tensile properties, fracture toughness, fatigue and creep-fatigue), irradiation creep and void swelling. The effect of irradiation on the microstructure of copper and copper alloys and dislocation channeling is also presented. Joining techniques for copper alloys in fusion plasma facing components are briefly discussed.
Li, Meimei [Argonne National Laboratory (ANL); Zinkle, Steven J [ORNL
Solid solution lithium alloy cermet anodes
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.
Richardson, Thomas J.
Aluminum Alloys
High Thermal Energy Storage Density LiNO3-KNO3-NaNO2-KNO2 Quaternary Molten Salt System for Parabolic Trough Concentrating Solar Power Generation.
Dispersoid reinforced alloy powder and method of making
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.
Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)
Fano type quantum inequalities in terms of $q$-entropies
Generalizations of the quantum Fano inequality are considered. The notion of $q$-entropy exchange is introduced. This quantity is concave in each of its two arguments. For $q\\geq0$, the inequality of Fano type with $q$-entropic functionals is established. The notion of coherent information and the perfect reversibility of a quantum operation are discussed in the context of $q$-entropies. By the monotonicity property, the lower bound of Pinsker type in terms of the trace norm distance is obtained for the Tsallis relative $q$-entropy of order $q=1/2$. For $0\\leq{q}\\leq2$, Fano type quantum inequalities with freely variable parameters are obtained.
Alexey E. Rastegin
Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal ({\\em i.e.}referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss of information about the state makes it impossible to distinguish between quantum and classical correlations. Here we show how the joint knowledge of the global and marginal degrees of information of a quantum state, quantified by the purities or in general by information entropies, provides an accurate characterization of its entanglement. In particular, for Gaussian states of continuous variable systems, we classify the entanglement of two--mode states according to their degree of total and partial mixedness, comparing the different roles played by the purity and the generalized $p-$entropies in quantifying the mixedness and bounding the entanglement. We prove the existence of strict upper and lower bounds on the entanglement and the existence of extremally (maximally and minimally) entang...
Adesso, G; Illuminati, F; Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio
Microscopic entropy of nondilatonic branes: A 2D approach
We investigate nondilatonic p-branes in the near-extremal, near-horizon regime. A two-dimensional gravity model, obtained from dimensional reduction, gives an effective description of the brane. We show that the AdS{sub p+2}/CFT{sub p+1} correspondence at finite temperature admits an effective description in terms of a AdS{sub 2}/CFT{sub 1} duality endowed with a scalar field, which breaks the conformal symmetry and generates a nonvanishing central charge. The entropy of the CFT{sub 1} is computed using Cardy formula. Fixing in a natural way a free, dimensionless, parameter introduced in the model by a renormalization procedure, we find exact agreement between the CFT{sub 1} entropy and the Bekenstein-Hawking entropy of the brane.
Cadoni, Mariano; Serra, Nicola [Dipartimento di Fisica, Universita di Cagliari, and INFN sezione di Cagliari, Cittadella Universitaria 09042 Monserrato (Italy)
Time Evolution of Entanglement Entropy from Black Hole Interiors
We compute the time-dependent entanglement entropy of a CFT which starts in relatively simple initial states. The initial states are the thermofield double for thermal states, dual to eternal black holes, and a particular pure state, dual to a black hole formed by gravitational collapse. The entanglement entropy grows linearly in time. This linear growth is directly related to the growth of the black hole interior measured along "nice" spatial slices. These nice slices probe the spacelike direction in the interior, at a fixed special value of the interior time. In the case of a two-dimensional CFT, we match the bulk and boundary computations of the entanglement entropy. We briefly discuss the long time behavior of various correlators, computed via classical geodesics or surfaces, and point out that their exponential decay comes about for similar reasons. We also present the time evolution of the wavefunction in the tensor network description.
Thomas Hartman; Juan Maldacena
Oxidation of alloys for advanced steam turbines
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.
Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, M.
Oxidation of advanced steam turbine alloys
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.
Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.
Cold worked ferritic alloys and components
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.
Korenko, Michael K. (Wexford, PA)
Query on Negative Temperature, Internal Interactions and Decrease of Entropy
After negative temperature is restated, we find that it will derive necessarily decrease of entropy. Negative temperature is based on the Kelvin scale and the condition dU>0 and dS0. But, negative temperature is contradiction with usual meaning of temperature and with some basic concepts of physics and mathematics. It is a question in nonequilibrium thermodynamics. We proposed a possibility of decrease of entropy due to fluctuation magnified and internal interactions in some isolated systems. From this we discuss some possible examples and theories.
Information loss and entropy conservation in quantum corrected Hawking radiation
It was found in [Phys.Lett.B 675 (2009) 98] that information is conserved in the process of black hole evaporation, by using the tunneling formulism and considering the correlations between emitted particles. In this Letter, we shall include quantum gravity effects, by taking into account of the log-area correction to Bekenstein-Hawking entropy. The correlation between successively emitted particles is calculated, with Planck-scale corrections. By considering the black hole evaporation process, entropy conservation is checked, and the existence of black hole remnant is emphasized. We conclue in this case information can leak out through the radiation and black hole evaporation is still a unitary process.
Yi-Xin Chen; Kai-Nan Shao
Applications of lattice dynamics theory: Calculating vibrational entropy in alloys and dielectric losses in ceramics
W. Simmons 1988 John Crawford, Jr. Spencer F. Eccles Tom C. Korologos Dorothy Snow 1989 Bruce L Spencer Williams 1963 Grant Johannesen V. Fae Thomas Wallace Stegner G. Stanley McAllister 1964 Homer R W. Burt Robert L. Chambers Bryon A. Hunter #12;1979 Bernard P. Brockbank R. Adams Cowley, M
Ceder, Gerbrand
The band structure-matched and highly spin-polarized Co{sub 2}CrZ/Cu{sub 2}CrAl Heusler alloys interface
Here we present a lattice- and band-matched nonmagnetic L21 Heusler alloy spacer for Co{sub 2}CrZ Heusler alloys where Z=Si or Al. By first principle calculations, we find that the band structure matching is almost perfectly satisfied when they are interfaced with Cu{sub 2}CrAl. Despite the loss of half-metallicity due to interface states, our calculations show that the spin polarization at these band-matched (001) interfaces is higher than 80%. These lattice-matched Co{sub 2}CrZ/Cu{sub 2}CrAl interfaces with excellent band matching and enhanced spin scattering asymmetry are promising for all-metallic current-perpendicular-to-plane giant magnetoresistance device applications.
Ko, V.; Han, G.; Qiu, J. [Data Storage Institute, Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608 (Singapore); Feng, Y. P. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
First second- and third-order entropies of Arabic text (Corresp.)
The first- second- and third-order entropies of written Arabic text are calculated. The calculated value of the third-order entropy shows that a redundancy of more than 50 percent is exhibited by the text.
M. Wanas; A. Zayed; M. Shaker; E. Taha
Synthesis of molybdenum disilicide by mechanical alloying
We have used mechanical alloying (MA), a high-energy ball-milling process, to prepare MoSi{sub 2} and MoSi{sub 2}-based alloys starting from mixtures of the pure elements. This synthesis route has the potential for preparing oxygen-free MoSi{sub 2} and the flexibility for close control of second-phase additions. MA, first developed for producing oxide-dispersions in Ni-based superalloys, takes advantage of the atomic-level mixing accomplished by the intense mechanical working of the alloy constituents. All the alloying reactions during the process occur in the solid-state. This technique is thus well-suited for synthesizing high melting point materials such as MoSi{sub 2}. The product of the MA process is a highly homogeneous and fine-grained powder. Its purity is determined by the purity of the starting materials and possible impurities introduced during processing. However, a careful control of the MA process enables a minimization of the impurities. We also report here the consolidation of the mechanically alloyed powder and the characterization of the MoSi{sub 2} alloys by optical and transmission electron microscopy, x-ray diffraction, and mechanical property measurements. 21 refs., 9 figs.
Schwarz, R.B.; Srinivasan, S.R.; Petrovic, J.J.; Maggiore, C.J.
Oxidation Potential of the Pu(III)-Pu(IV) Couple in Percloric Acid So lution. Heat Content and Entropy Change
the three oxidation states of plutonium compare very closelyemployed in the calculation of the Plutonium entropies. Thevalues for uranium and' plutonium entropy is much closer-
Connick, Robert E.
The effect of the shape function on small-angle scattering analysis by the maximum entropy method
Analysis of small-angle scattering data to obtain a particle size distribution is dependent upon the shape function used to model the scattering. Using a maximum entropy analysis of small-angle scattering data, the effect of shape function selection on obtained size distribution is demonstrated using three different shape functions to describe the same scattering data from each of two steels. The alloys have been revealed by electron microscopy to contain a distribution of randomly oriented and mainly non-interacting, irregular, ellipsoidal precipitates. Comparison is made between the different forms of the shape function. Effect of an incident wavelength distribution is also shown. The importance of testing appropriate shape functions and validating these against other microstructural studies is discussed.
Jemian, P.R. [Argonne National Lab., IL (United States); Allen, A.J. [Univ. of Maryland, College Park, MD (United States). Department of Physics]|[National Inst. of Standards and Technology, Gaithersburg, MD (United States)
The production rate of the coarse grained Gibbs entropy and the Kolmogorov-Sinai entropy: a real connection ?
We discuss the connection between the Kolmogorov-Sinai entropy, $h_{KS}$, and the production rate of the coarse grained Gibbs entropy, $r_G$. Detailed numerical computations show that the (often accepted) identification of the two quantities does not hold in systems with intermittent behavior and/or very different characteristic times and in systems presenting pseudo-chaos. The basic reason of this fact is in the asymptotic (with respect to time) nature of $h_{KS}$, while $r_G$ is a quantity related to short time features of a system.
Massimo Falcioni; Luigi Palatella; Angelo Vulpiani
Acoustic and entropy waves in a combustion MHD generator
Simultaneous, sensitive, high frequency measurements of pressure and temperature fluctuations associated with traveling acoustic and entropy pulses were made in a combustion MHD generator under conditions of applied magnetic field (up to 2.2 Tesla) and moderate current density (up to 1.0 amp per square centimeter). The experimental observations and a closed form analytical description of the magneto-acoustic interaction suggest that non-ideal phenomena, including near electrode phenomena, heat transfer, and possible secondary flows can substantially inhibit wave growth or attenuation caused by magneto-acoustic instabilities. Disturbances in the plasma temperature and pressure were created by the rapid discharge of a capacitor into the moving conducting plasma. Inside the generator, transient measurements were taken at three locations using a probe-tube microphone for pressure measurements, a fiber-optic luminosity probe for relative temperature measurements, and transverse mounted voltage pins to measure local voltage profiles. The pressure waves in a laboratory scale generator are not appreciably affected by MHD phenomena, as anticipated from analytical predictions. Temperature waves are affected by the presence of magnetic field and current, showing small attenuation at low currents, greater attenuation at higher currents, and greatest attenuation when either or both magnetic field or currents are absent. These data are explained by a model for secondary flows which affects heat transfer from the plasma. Application of a model for the magneto-acoustic phenomena in large scale MHD generators indicates that property fluctuations may grow appreciably if the electrical resistance in the electrode boundary layers is small with respect to the resistance of the plasma core.
Simons, T.D.
Information-theoretic CAD system in mammography: Entropy-based indexing for computational efficiency and robust performance
We have previously presented a knowledge-based computer-assisted detection (KB-CADe) system for the detection of mammographic masses. The system is designed to compare a query mammographic region with mammographic templates of known ground truth. The templates are stored in an adaptive knowledge database. Image similarity is assessed with information theoretic measures (e.g., mutual information) derived directly from the image histograms. A previous study suggested that the diagnostic performance of the system steadily improves as the knowledge database is initially enriched with more templates. However, as the database increases in size, an exhaustive comparison of the query case with each stored template becomes computationally burdensome. Furthermore, blind storing of new templates may result in redundancies that do not necessarily improve diagnostic performance. To address these concerns we investigated an entropy-based indexing scheme for improving the speed of analysis and for satisfying database storage restrictions without compromising the overall diagnostic performance of our KB-CADe system. The indexing scheme was evaluated on two different datasets as (i) a search mechanism to sort through the knowledge database, and (ii) a selection mechanism to build a smaller, concise knowledge database that is easier to maintain but still effective. There were two important findings in the study. First, entropy-based indexing is an effective strategy to identify fast a subset of templates that are most relevant to a given query. Only this subset could be analyzed in more detail using mutual information for optimized decision making regarding the query. Second, a selective entropy-based deposit strategy may be preferable where only high entropy cases are maintained in the knowledge database. Overall, the proposed entropy-based indexing scheme was shown to reduce the computational cost of our KB-CADe system by 55% to 80% while maintaining the system's diagnostic performance.
Tourassi, Georgia D.; Harrawood, Brian; Singh, Swatee; Lo, Joseph Y. [Digital Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Digital Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27710 (United States)
Properties of Conventionally Alloyed and Powder Alloyed Nano ...
Presentation Title, Properties of Conventionally Alloyed and Powder Alloyed Nano-Crystalline Titanium Consolidated Via Spark Plasma Sintering. Author(s) ...
Ductile filler metal alloys for welding nickel aluminide alloys
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.
Santella, Michael L. (Knoxville, TN); McNabb, Jeffrey D. (Lenoir City, TN); Sikka, Vinod K. (Oak Ridge, TN)
Uranium-titanium-niobium alloy
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.
Ludtka, Gail M. (Oak Ridge, TN); Ludtka, Gerard M. (Oak Ridge, TN)
Distribution of Entropy of Bardeen Regular Black Hole with Corrected State Density
We consider corrections to all orders in the Planck length on the quantum state density, and calculate the statistical entropy of the scalar field on the background of the Bardeen regular black hole numerically. We obtain the distribution of entropy which is inside the horizon of black hole and the contribution of the vicinity of horizon takes a great part of the whole entropy.
Hai Huang; Juhua Chen; Yongjiu Wang
Relative Entropy and Free Energy Dualities: Connections to Path Integral and KL control
Relative Entropy and Free Energy Dualities: Connections to Path Integral and KL control Evangelos A and the fundamental dualities between free energy and relative entropy. We derive the path integral optimal control on Dynamic Programming with PI based on the duality between free energy and relative entropy. Moreover we
Anderson, Richard
Low activation ferritic alloys
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.
Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.
A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.
Schonfeld, F.W.; Waber, J.T.
Gelles, David S. (West Richland, WA); Ghoniem, Nasr M. (Granada Hills, CA); Powell, Roger W. (Pasco, WA)
Breakthrough Research on Platinum-Nickel Alloys
Breakthrough Research on Platinum-Nickel Alloys Print Breakthrough Research on Platinum-Nickel Alloys Print Two out of three of the kinetic barriers to the practical use of polymer electrolyte membrane (PEM) hydrogen fuel cells in automobiles have been breached: the impractically high amount of extra energy needed for the oxidation reduction reaction (ORR) on the catalyst and the loss of catalytic surface areas available for ORR. Using a combination of probes and calculations, a group of scientists has demonstrated that the Pt3Ni(111) alloy is ten times more active for ORR than the corresponding Pt(111) surface and ninety times more active than the current state-of-the-art Pt/C catalysts used in existing PEM fuel cells. This new variation of the platinum-nickel alloy is the most active oxygen-reducing catalyst ever reported.
Breakthrough Research on Breakthrough Research on Platinum-Nickel Alloys Breakthrough Research on Platinum-Nickel Alloys Print Wednesday, 28 February 2007 00:00 Two out of three of the kinetic barriers to the practical use of polymer electrolyte membrane (PEM) hydrogen fuel cells in automobiles have been breached: the impractically high amount of extra energy needed for the oxidation reduction reaction (ORR) on the catalyst and the loss of catalytic surface areas available for ORR. Using a combination of probes and calculations, a group of scientists has demonstrated that the Pt3Ni(111) alloy is ten times more active for ORR than the corresponding Pt(111) surface and ninety times more active than the current state-of-the-art Pt/C catalysts used in existing PEM fuel cells. This new variation of the platinum-nickel alloy is the most active oxygen-reducing catalyst ever reported.
Entropy Growth and the Dark Energy Equation of State
We revisit the conjecture of a generalized second law of thermodynamics which states that the combined entropy of matter and horizons must grow. In an expanding universe a generalized second law restricts the equation of state. In particular, it conflicts with long phases of a phantom, wstate.
Wilfried Buchmuller; Joerg Jaeckel
CONSTRAINED MINIMUM ENTROPY AND MAXIMUM NEGENTROPY BLIND DECONVOLUTION AND EQUALIZATION Seungjin on the variance of decon volved signal. We also consider the maximum negen tropy principle and show that the CME version, without any prior knowledge (such as channel impulse response, training data). As the demand
Choi, Seungjin
Non-dissipative hydrodynamics: Effective actions versus entropy current
While conventional hydrodynamics incorporating dissipative effects is hard to derive from an action principle, it is nevertheless possible to construct classical actions when the dissipative terms are switched off. In this note we undertake a systematic exploration of such constructions from an effective field theory approach and argue for the existence of non-trivial second order non-dissipative hydrodynamics involving pure energy-momentum transport. We find these fluids to be characterized by five second-order transport coefficients based on the effective action (a three parameter family is Weyl invariant). On the other hand since all flows of such fluids are non-dissipative, they entail zero entropy production; one can therefore understand them using the entropy current formalism which has provided much insight into hydrodynamic transport. An analysis of the most general stress tensor with zero entropy production however turns out to give a seven parameter family of non-dissipative hydrodynamics (a four parameter sub-family being Weyl invariant). The non-dissipative fluids derived from the effective action approach are a special case of the fluid dynamics constrained by conservation of the entropy current. We speculate on the reasons for the mismatch and potential limitations of the effective action approach.
Jyotirmoy Bhattacharya; Sayantani Bhattacharyya; Mukund Rangamani
Identification of probable real words: an entropy-based approach
This paper proposes a method for identifying probable real words among out-of-vocabulary (OOV) words in text. The identification of real words is done based on entropy of probability of character trigrams as well as the morphological rules of English. ...
Youngja Park
Entropy of Spacelike Two-Surfaces of Spacetime
We argue that every finite piecewise smooth spacelike two-surface of spacetime possesses an entropy which is, in natural units, one quarter of its area. However, the thermodynamical properties of a two-surface become apparent only to the observers having that two-surface as a horizon. Consequences of this result are discussed.
J. Makela; A. Peltola
Entropy production determination of the ambipolar solution nearest equilibrium
A general derivation of the steady state entropy production equation is presented for a confined plasma which loses particles and energy via radial transport and, perhaps, end loss. The resulting equation is employed to determine which root or solution is closest to thermodynamic equilibrium when more than one self-consistent or ambipolar solution is possible.
Catto, P.J.; Myra, J.R.
Aluminum Extrusion Alloys
Table 1Â Â Â Aluminum extrusion alloys by series...6063 (1944), 6066, 6070, 6082 (1972), 6101 (1954), 6105 (1965),
Shape Memory Alloys
Scope, Shape memory alloys (SMA) have received widespread attention from ... The symposium focuses on shape memory and superelastic materials and their ...
(HSBC) of Aluminum Alloy
Effect of Fe Doping on the Mechanical Properties of TiNi Alloys · Electromagnetic Stirring of Plutonium Metal Part I: Theoretical Calculations and System Design ...
Grain Refining Aluminum Alloys
He has had responsibility within Alcoa for optimizing grain refining and alloying ... of grain refinement; Methods of grain refining; Attributes of chemical inoculants ...
Blade Alloys - TMS
PDF PRESENTATION: Evolution of Ni-Based Superalloy Turbine Blades Highlights alloy development programs, as well as various processes, 1, 1272, Lynette ...
Ductile nickel-silicon alloy
An improvement over prior compositions wherein the ductility of Ni-Si alloys are improved with minor alloying additions of hafnium or zirconium.
Oliver, W.C.
Electron Metallography of Alloy 718
Electron Metallography of Alloy 718. John F. Radavich. Emeritus Professor. Purdue University. West Lafayette, IN 47907. Abstract. Alloy 718 is unique in that it ...
Alloy 740 Weld Strength Optimization
Symposium, Properties, Processing, and Performance of Steels and Ni-Based Alloys for Advanced Steam Conditions. Presentation Title, Alloy 740 Weld ...
Numerical Approach for Development of High Elastic Casting ...
This study is suggested how to make high elastic aluminum alloys using ... Frequency Modulation Effect on the Solidification of Alloy 718 Fusion Zone.
Processing of High-temperature Structural Materials I
Subsurface Alloy Microstructural Changes During High Temperature Reaction of Fe-Cr Alloys in CO2: David Young1; Thuan Nguyen1; Jianqiang Zhang1; ...
Rare event simulation and combinatorial optimization using cross entropy: estimation of rare event probabilities using cross-entropy
This paper deals with estimation of probabilities of rare events in static simulation models using a fast adaptive two-stage procedure based on importance sampling and Kullback-Liebler's cross-entropy (CE). More specifically, at the first stage we estimate ...
Tito Homem-de-Mello; Reuven Y. Rubinstein
Tribo-Mechanical Evaluations of Cobalt-Based (Stellite 4) Alloys Manufactured via HIPing and Casting
Abstract — Cobalt-based alloys are known for their excellent wear resistance, particularly under high temperature and corrosive environments. However the cast cobalt-based alloys have relatively high brittleness, and low toughness, due to their coarse carbide structure. This paper aims to comprehend if carbide refinement, caused by changing the processing route from sand casting to powder consolidated Hot Isostatic Pressing (HIPing), can improve the tribo-mechanical properties of cobalt-based alloys. The alloy selected for this investigation had a nominal wt. % composition of Co-30Cr-14W-1C, which is similar to the composition of the commercially available Stellite®4 alloy. The Hot Isostatic Pressed (HIPed) alloy had a much finer microstructure than the cast alloy, which showed a typical hypoeutectic dendritic microstructure. Both alloys had similar hardness. Although the cast alloy showed slightly better abrasive and sliding wear resistance than the HIPed alloy due to their coarser eutectic carbides, the HIPed alloy had a significant advantage on the impact toughness and contact fatigue performance. The results of this comparative investigation indicated that the HIPed alloy had an attractive combination of tribo-mechanical properties, i.e. improved impact and fatigue resistance, whilst preserving the high hardness and good wear resistance associated with the cast alloy, making it suitable for relatively higher stress applications.
H. Yu; R. Ahmed; H. De Villiers Lovelock; S. Davies
Intermetallic alloy welding wires and method for fabricating the same
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.
Santella, M.L.; Sikka, V.K.
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.
Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)
Shape memory alloys
A shape memory alloy is disclosed consisting essentially of, by weight ratio, 2 to 15% aluminium, 0.01 to 3% beryllium and the balance being substantially copper, with impurities being inevitably present in the process of preparation, and a shape memory alloy further including 0.05 to 15% zinc, both including composition ranges which allows cold work.
Suzuki, K.
Aluminum battery alloys
Aluminum alloys suitable for use as anode structures in electrochemical cells are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.
Thompson, D.S.; Scott, D.H.
Neutron Absorbing Alloys
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.
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)
Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.
Thompson, David S. (Richmond, VA); Scott, Darwin H. (Mechanicsville, VA)
An alloy is presented for use as a reactor fuel. The binary alloy consists essentially of from about 5 to 90 atomic per cent cerium and the balance being plutonium. A complete phase diagram for the cerium--plutonium system is given.
Coffinberry, A.S.
Copper-tantalum alloy
A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.
Schmidt, Frederick A. (Ames, IA); Verhoeven, John D. (Ames, IA); Gibson, Edwin D. (Ames, IA)
Microstructure and Mechanical Properties of 3003 Aluminum Alloy ...
... reason of property improvement, especially high temperature performance. ... High Strength Aluminum Brazing Sheets for Condenser Fins of Automotive ... predictions for the phase formation in a wide range of commercial aluminum alloys.
Structural alloy with a protective coating containing silicon or silicon-oxide
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.
Natesan, K.
Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion
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.
Steeves, Arthur F. (Schenectady, NY); Bibb, Albert E. (Clifton Park, NY)
Hawking radiation and total entropy change as tunneling
In the frame of Hamilton-Jacobi method, the back-reactions of the radiating particles together with the total entropy change of the whole system are investigated. The emission probability from this processing is found to be equivalent to the null geodesic method. However the total entropy of the system, particles and black hole, is increased yet very little, which is a little different. This method can be applied to any sort of horizons and particles without a specific choice of (regular-across-the-horizon) coordinates. Its physical meaning is more obvious: the negative energy one of a virtual particle pair is absorbed by the black hole, resulting in the temperature, electric potential and angular velocity increase; then the black hole amount of heat, electric charge and angular momentum can spontaneously transfer to the positive energy particle; when obtaining enough energy, it can escape away to infinity, visible to distant observers.
Ding, Chikun
Time and Entropy in the Foundations of Mechanics
This contribution analyses the classical laws of motion by means of an approach relating time and entropy. We argue that adopting the notion of change of states as opposed to the usual derivation of Newton's laws in terms of fields a broader picture is obtained, suggesting that diverse branches of physics- classical, quantum, relativistic and statistical mechanics - turn out to be related by a common foundation.
R Assumpcao
Th, Si, anol Bt alloys where Be and Si are each present in anmounts between 0.1 and 3.5% by weight and the total weight per cent of the minor alloying elements is between 1.5 and 4.5% are discussed. These ternary alloys show increased hardness and greater resistant to aqueous corrosion than is found in pure Th, Th-Si alloys, or Th-Be alloys.
Foote, F.G.
Dynamical horizon entropy and equilibrium thermodynamics of generalized gravity theories
We study the relation between the thermodynamics and field equations of generalized gravity theories on the dynamical trapping horizon with sphere symmetry. We assume the entropy of a dynamical horizon as the Noether charge associated with the Kodama vector and point out that it satisfies the second law when a Gibbs equation holds. We generalize two kinds of Gibbs equations to Gauss-Bonnet gravity on any trapping horizon. Based on the quasilocal gravitational energy found recently for f(R) gravity and scalar-tensor gravity in some special cases, we also build up the Gibbs equations, where the nonequilibrium entropy production, which is usually invoked to balance the energy conservation, is just absorbed into the modified Wald entropy in the Friedmann-Robertson-Walker spacetime with slowly varying horizon. Moreover, the equilibrium thermodynamic identity remains valid for f(R) gravity in a static spacetime. Our work provides an alternative treatment to reinterpret the nonequilibrium correction and supports the idea that the horizon thermodynamics is universal for generalized gravity theories.
Wu Shaofeng; Ge Xianhui; Yang Guohong [Department of Physics, Shanghai University, Shanghai, 200444 (China); Shanghai Key Lab of Astrophysics, Shanghai, 200234 (China); Zhang Pengming [Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Institute of Modern Physics, Lanzhou, 730000 (China)
The hydrogen embrittlement of Ni-Cr-Fe alloys
It has been proposed that the stress corrosion cracking (SCC) of nickel-based alloys in low-temperature hydrogenated water is due to hydrogen embrittlement. The purpose of this work was to investigate the role of chromium on hydrogen embrittlement of Ni-Cr-Fe alloys and thus develop a better understanding of the low-temperature SCC phenomenon. The effect of chromium on the hydrogen embrittlement was examined using tensile tests followed by material evaluation via scanning electron microscopy and light optical microscopy. Four alloys were prepared with chromium contents ranging from 6 wt. percent to 35 wt. percent. In the noncharged condition, ductility, as measured by the percent elongation or reduction in area, increased as the alloy chromium content increased. Hydrogen appeared to have only minor effects on the mechanical properties of the low chromium alloys. The addition of hydrogen had a marked effect on the ductility of the higher chromium alloys. In the 26% chromium alloy, the elongation to failure was reduced from 53% to 14% with a change in fracture mode from ductile dimple to intergranular failure. A maximum in embrittlement was observed in the 26% Cr alloy. The maximum in embrittlement coincided with the minimum in stacking-fault energy. It is proposed that the increased hydrogen embrittlement in the high-chromium alloys is due to increased slip planarity caused by the low stacking-fault energy. Slip planarity did not appear to affect the fracture of the noncharged specimens.
Symons, D.M.
Rare Earth Metals and Alloys | Ames Laboratory
Mpc » Rare Earth Metals and Alloys Mpc » Rare Earth Metals and Alloys Rare Earth Metals and Alloys Terbium (Tb) and Cerium (Ce) phosphors in your computer screen allow you to see GREEN. Europium (Eu) is the source of the RED light and BLUE emitted by our display. The Ames Laboratory has been actively involved in the preparation of very pure rare earth metals since the early 1940's when Dr. Frank H. Spedding and his group of pioneers developed the ion-exchange process, a technique that separates the "fraternal fifteen" plus yttrium and scandium. As a result of this and subsequent work, high-purity oxides are available from which high-purity rare earth metals can be prepared. In most cases, the rare earth oxides are first converted to their respective fluorides and are then reduced metallothermicaly on a kilogram
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
with silicon carbide hollow spheres (SiCHS) is investigated for quasi-static (10-3 s-1 ) and high strain rate in increased interest in these materials. Particles, whiskers, short fibers, and continuous fibers of SiC have
Gupta, Nikhil
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
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.
Wang Wenhong; Sukegawa, Hiroaki; Shan Rong; Furubayashi, Takao; Inomata, Koichiro [Magnetic Materials Center, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan)
Magnesium - Rare Earth Alloys
Feb 16, 2010 ... Location: Washington State Convention Center ... The Use of Computer Modeling for Producing DC Cast WE43 Magnesium Alloy Slab: ... However, there is a limited operating window within which favourable textures arise.
Subtyping in alloy
A type system for the Alloy modelling language is described that supports subtypes and allows overloading of relation names. No special syntactic features needed to be added to the language to support the type system; there ...
Torlak, Emina, 1979-
Diffraction Analysis of Alloys
Feb 18, 2010 ... Neutron and X-Ray Studies of Advanced Materials III : Diffraction Analysis of Alloys .... at the Advanced Photon Source at Argonne National Laboratory in .... pure Zirconium was performed with the D-DIA apparatus at the APS.
Pu-U-Fe and Pu-U-Co alloys suitable for use as fuel elements tn fast breeder reactors are described. The advantages of these alloys are ease of fabrication without microcracks, good corrosion restatance, and good resistance to radiation damage. These advantages are secured by limitation of the zeta phase of plutonium in favor of a tetragonal crystal structure of the U/sub 6/Mn type.
Coffinberry, A.S.; Schonfeld, F.W.
Alloy 690 Procurement Specification
The metallurgical characteristics of Alloy 690 can play a role in its resistance to a propensity for primary water stress corrosion cracking (PWSCC) and its ultrasonic testing (UT) inspectability. More than 20 years of experience in building Alloy 690 components for pressurized water reactor replacement hardware and laboratory testing have generated a significant body of knowledge on material manufacturing practices and material attributes that optimize performance potential and inspectability. This spec...
Entropy production along a stochastic trajectory and an integral fluctuation theorem
For stochastic non-equilibrium dynamics like a Langevin equation for a colloidal particle or a master equation for discrete states, entropy production along a single trajectory is studied. It involves both genuine particle entropy and entropy production in the surrounding medium. The integrated sum of both $\\Delta s\\t$is shown to obey a fluctuation theorem $ =1$ for arbitrary initial conditions and arbitrary time-dependent driving over a finite time interval.
Udo Seifert
Laser welding of aluminum alloys
Recent interest in reducing the weight of automobiles to increase fuel mileage has focused attention on the use of aluminum and associated joining technologies. Laser beam welding is one of the more promising methods for high speed welding of aluminum. Consequently, substantial effort has been expended in attempting to develop a robust laser beam welding process. Early results have not been very consistent in the process requirements but more definitive data has been produced recently. This paper reviews the process parameters needed to obtain consistent laser welds on 5,000 series aluminum alloys and discusses the research necessary to make laser processing of aluminum a reality for automotive applications.
Leong, K.H.; Sabo, K.R.; Sanders, P.G. [Argonne National Lab., IL (United States). Technology Development Div.; Spawr, W.J.
Thermophysical Properties of U-10MO Alloy
This report provides an overview of thermophysical properties of unirradiated uranium alloyed with ten weight percent molybdenum (U 10Mo), with particular focus on those material properties needed for modeling of new fuels for HPRRs (High Performance Research Reactors). The report contains both historical data available in the literature on U-10Mo, as well as more recent results conducted by the Global Threat Reduction Initiative fuel development program. The main use of the report is intended as a standard U-10Mo alloy properties reference for reactor models and simulations.
A. M. Phillips; G. S. Mickum; D. E. Burkes
Range-Renewal Speed and Entropy for I.I.D Models
In this note the relation between the range-renewal speed and entropy for i.i.d. models is discussed.
Xin-Xing Chen; Jian-Sheng Xie; Jiangang Ying
Quantum substitutions of Pisot type, their quantum topological entropy and their use for optimal spacing
Quantum substitutions of Pisot type (and their quantum topological entropy) are introduced. Their utility as algorithms for optimal spacing is analyzed.
Gavriel Segre
CD2Alloy: class diagrams analysis using alloy revisited
We present CD2Alloy, a novel, powerful translation of UML class diagrams (CDs) to Alloy. Unlike existing translations, which are based on a shallow embedding strategy, and are thus limited to checking consistency and generating conforming object models ...
Shahar Maoz; Jan Oliver Ringert; Bernhard Rumpe
Development of Advanced Alloys and Coating Systems for ...
Oct 8, 2012 ... Oil drilling bit cutting inserts, made of cemented tungsten carbide, are prone to ... Nickel alloys cost 40-50X as much as high strength steel.
Current Production Status of Alloy 718 Turbine Disks in China
For the past few years the production of high quality alloy 7 18 turbine disks has made great strides ... The main technology studies which led to the production of.
Potential Next Generation Airfoil Alloys for Advanced Land-Base ...
... state-of-the-art Ni-base superalloys (i.e., hydrogen or oxy-combustion firing conditions). ... High-Temperature Oxidation Behaviour of Co-Re-Cr-Based Alloys.
Solid State Phase Transformations in Uranium-Zirconium Alloys
Uranium-10wt% zirconium (U-10Zr) alloy nuclear fuels have been used for decades and new variations are under consideration ranging from U-5Zr to U-50Zr. As a precursor to understanding the fission gas behavior in U-Zr alloys using ion implantation, a basic study on the U-Zr metallurgy was completed using EPMA, DSC, XRD, Optical microscopy, and TEM with a focus on solid state phase transformations in alloys containing 2, 5, 10, 20, 30, and 50wt% zirconium. Alloys were cast by crucible melting using high temperature furnace under argon atmosphere in yttrium oxide crucibles and various thermal profiles were used to study phase transformations in these alloys. Using TEM, XRD, and DSC data, it was ascertained that athermal-?, along with martensitic ?1, formed in all alloys quenched from ? phase. XRD could detect the presence of athermal-? only in U-20, 30 and 50wt%Zr alloys. BSE images for as-cast alloys of 2, 5, 10, 20, and 30wt%Zr had lamellar microstructure with lamellae rich in zirconium. All alloy samples clearly showed a heating transformation pertaining to ? ? ? in DSC data while XRD could only confirm the presence of ? phase in U-20, 30, and 50wt%Zr alloys. An explanation is offered for the absence of ? phase peaks in uranium-rich alloys based on its formation mechanism. Alloy samples of U-2, 5, and 10wt%Zr were step-cooled from ? phase by annealing in the (? + ?) phase field before cooling to room temperature revealed broad peaks for ? phase indicating incomplete collapse of {111}? planes. Both as cast and ?- quenched alloys were annealed at 600degreeC, in the (? + ?) phase field for 1, 3, 7, and 30 days. Microstructures of the samples in both cases contained uranium-rich matrix and zirconium-rich precipitates and WDS analyses were consistent with their being ?-U and ? phase respectively. However, XRD data for annealed alloys never showed peaks for ? phase even though it's area fraction was within the detection limits. Moreover, the peaks which were present in U-20wt%Zr vanished after annealing for 7 days. Based on the data obtained, it is suggested that it is more appropriate to consider the presence of metastable diffusional-? instead of a stable ? in the as-cast alloys and that it is not stable at 600degreeC.
Irukuvarghula, Sandeep
Single Min-Entropy Random Source can be Amplified
Expansion and amplification of weak randomness with the help of untrusted quantum devices is a hot topic of current research. Here we contribute with a procedure for amplifying a single weak random source with the help of tri-partite GHZ-type entangled states. If the quality of the source measured in min-entropy rate reaches a fixed threshold $log_2(\\sqrt{3})$, perfect random bits can be produced. Presented procedure works well also on locally bit-fixing random sources, which cannot be characterized as Santha--Vazirani sources and thus using existing amplification procedures cannot be applied.
Martin Plesch; Matej Pivoluska
Entropy, Entanglement, and Transition Probabilities in Neutrino Oscillations
We show that the phenomenon of flavor oscillations can be described in terms of entangled flavor states belonging to the classes of Bell and W states. We analyze bipartite and multipartite flavor entanglements as measured by the reduced linear entropies of all possible bipartitions. Such entanglement monotones are found to be essentially equivalent to the flavor transition probabilities, that are experimentally accessible quantities. Therefore entanglement acquires a novel, operational physical characterization in the arena of elementary particle physics. We discuss in detail the fundamental cases of two- and three-flavor neutrino oscillations.
Blasone, Massimo; De Siena, Silvio; Illuminati, Fabrizio
Validity and failure of some entropy inequalities for CAR systems
Basic properties of von Neumann entropy such as the triangle inequality and what we call MONO-SSA are studied for CAR systems. We show that both inequalities hold for any even state. We construct a certain class of noneven states giving counter examples of those inequalities. It is not always possible to extend a set of prepared states on disjoint regions to some joint state on the whole region for CAR systems. However, for every even state, we have its `symmetric purification' by which the validity of those inequalities is shown. Some (realized) noneven states have peculiar state correlations among subsystems and induce the failure of those inequalities.
Hajime Moriya
Development of Novel Gamma TiAl Alloys and Their Joining ...
The master alloys having ultimate strength as high as 560 MPa at 900 oC are fabricated by ... Processing and Mechanical Behavior of Unalloyed Plutonium.
Development of Heusler-type Fe 2 VAl alloys for thermoelectric ...
Abstract Scope, A Heusler alloy, Fe2VAl, is a promising candidate for thermoelectric power generation because of its high thermoelectric power ...
TEM Study on Microstructure Behavior of Alloy 718 After Long Time ...
Besides 6 phase formation, y" , y' and 6 coarsening and solution were observed. The softening mechanisms of. Alloy 718 at high temperatures have been ...
Microstructures and oxidation behavior of some Molybdenum based alloys
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.
Ray, Pratik Kumar
Entropy In The Present And Early Universe: New Small Parameters And Dark Energy Problem
It is demonstrated that entropy and its density play a significant role in solving the problem of the vacuum energy density (cosmological constant) of the Universe and hence the dark energy problem. Taking this in mind, two most popular models for dark energy - Holographic Dark Energy Model and Agegraphic Dark Energy Model - are analyzed. It is shown that the fundamental quantities in the first of these models may be expressed in terms of a new small dimensionless parameter. It is revealed that this parameter is naturally occurring in High Energy Gravitational Thermodynamics and Gravitational Holography (UV-limit). On this basis the possibility of a new approach to the problem of Quantum Gravity is discussed. Besides, the results obtained on the uncertainty relation of the pair "cosmological constant - volume of space-time", where the cosmological constant is a dynamic quantity, are reconsidered and generalized up to the Generalized Uncertainty Relation.
A. E. Shalyt-Margolin
Entropy In The Present And Early Universe, New Small Parameters And Dark Energy Problem
It is demonstrated that entropy and its density play a significant role in solving the problem of the vacuum energy density (cosmological constant) of the Universe and hence the dark energy problem. Taking this in mind, two most popular models for dark energy - Holographic Dark Energy Model and Agegraphic Dark Energy Model - are analyzed. It is shown that the fundamental quantities in the first of these models may be expressed in terms of a new small dimensionless parameter. It is revealed that this parameter is naturally occurring in High Energy Gravitational Thermodynamics and Gravitational Holography (UV-limit). On this basis the possibility of a new approach to the problem of Quantum Gravity is discussed. Besides, the results obtained on the uncertainty relation of the pair "cosmological constant - volume of space-time", where the cosmological constant is a dynamic quantity, are reconsidered and generalized up to the Generalized Uncertainty Relation
Shalyt-Margolin, A E
Precipitation-Hardenable Nickel Alloys
Table 4Â Â Â Properties of selected mechanically alloyed materials...intended application temperature for
Physical Metallurgy and Alloy Development
FORUMS > PHYSICAL METALLURGY AND ALLOY DEVELOPMENT ... A TMS Knowledge Packet on the Physical Metallurgy of Solders and Solder Interfaces
Method of making active magnetic refrigerant materials based on Gd-Si-Ge alloys
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.
Pecharsky, Alexandra O. (Ames, IA); Gschneidner, Jr., Karl A. (Ames, IA); Pecharsky, Vitalij K. (Ames, IA)
De-alloyed platinum nanoparticles
A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.
Strasser, Peter (Houston, TX); Koh, Shirlaine (Houston, TX); Mani, Prasanna (Houston, TX); Ratndeep, Srivastava (Houston, TX)
Entropy production for an interacting quark-gluon plasma
We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D Bjorken scenario, appropriate for the early longitudinal expansion stage of the collision. Going beyond the standard simplification of a massless ideal gas we consider a realistic equation of state consistently derived within a virial expansion. The EoS used is well in line with recent three-flavor QCD lattice data for the pressure, speed of sound, and interaction measure at nonzero temperature and vanishing chemical potential ($\\mu_{\\rm q} = 0$). The shear viscosity has been consistently calculated within this formalism using a kinetic approach in the ultra-relativistic regime with an explicit and systematic evaluation of the transport cross section as function of temperature. We investigate the influence of the viscosity and the initial condition, i.e. formation time, initial temperature, and pressure anisotropy for the entropy production at RHIC at $\\sqrt{s_{\\rm NN}}=130$ GeV. We find that the interplay between effects of the viscosity and of the realistic EoS can not be neglected in the reconstruction of the initial state from experimental data. Therefore, from the experimental findings it is very hard to derive unambiguous information about the initial conditions and/or the evolution of the system.
Stefano Mattiello
Photosynthetic models with maximum entropy production in irreversible charge transfer steps
Steady-state bacterial photosynthesis is modelled as cyclic chemical reaction and is examined with respect to overall efficiency, power transfer efficiency, and entropy production. A nonlinear flux-force relationship is assumed. The simplest two-state ... Keywords: Bacterial photosynthesis, Efficiency, Entropy production, Kinetic models, Power
Davor Jureti?; PašKo Upanovi?
Parametric analysis of entropy generation in a channel filled with a porous medium
The entropy generation of a mixed convection flow in an inclined channel filled with a porous medium, is studied in the present paper. The constant flow rate is considered upward and the uniform wall heat flux is into the channel. The analytical solutions ... Keywords: differential equations, entropy generation, mixed convection, porous medium
Dalia Sabina Cimpean; Ioan Pop
The Application of Unascertained Measure Model in Bofang Coal Mine Evaluation Based on Information Entropy
In recent years, coal mine safety is an urgent problem needs to be solved in China. The article takes into account the impact of the safety evaluation factors of traditional coal mines (taking the Bofang mine as an example), using information entropy ... Keywords: information entropy, safety evaluation index, unascertained measure model, Bofang mine
Zhanglin Guo; Zhaopeng Liu
Inference of restricted stochastic boolean GRN's by Bayesian error and entropy based criteria
This work compares two frequently used criterion functions in inference of gene regulatory networks (GRN), one based on Bayesian error and another based on conditional entropy. The network model utilized was the stochastic restricted Boolean network ... Keywords: Bayesian error, entropy, feature selection, gene regulatory networks inference, stochastic restricted Boolean network models
David Correa Martins, Jr.; Evaldo Araújo De Oliveira; Vitor Hugo Louzada; Ronaldo Fumio Hashimoto
Cobalt-Base Alloys
Table 4Â Â Â Nominal compositions of various cobalt-base alloys...Si Mn Others Cobalt-base wear-resistant alloys Stellite 1 bal 31 12.5 1 (max) 2.4 3 (max) 3 (max) 2 (max) 1 (max) â?¦ Stellite 6 bal 28 4.5 1 (max) 1.2 3 (max) 3 (max) 2 (max) 1 (max) â?¦ Stellite 12 bal 30 8.3 1 (max) 1.4 3 (max) 3 (max) 2 (max) 1 (max) â?¦ Stellite 21 bal 28 â?¦ 5.5 0.25 2 (max) 2.5 2 (max) 1...
Determination of the Heat-Transport Coefficient in Energy-Balance Climate Models by Extremization of Entropy Production
Entropy production has been calculated as a function of the coefficient of meridional heat transfer for two seasonal energy-balance climate models. Both models display extrema in entropy production at values of the coefficient appropriate to the ...
P. H. Wyant; A. Mongroo; S. Hameed
Entropy Budget of an Atmosphere in Radiative–Convective Equilibrium. Part I: Maximum Work and Frictional Dissipation
The entropy budget of an atmosphere in radiative–convective equilibrium is analyzed here. The differential heating of the atmosphere, resulting from surface heat fluxes and tropospheric radiative cooling, corresponds to a net entropy sink. In ...
Olivier Pauluis; Isaac M. Held
Logarithmic Corrections to N=2 Black Hole Entropy: An Infrared Window into the Microstates
Logarithmic corrections to the extremal black hole entropy can be computed purely in terms of the low energy data -- the spectrum of massless fields and their interaction. The demand of reproducing these corrections provides a strong constraint on any microscopic theory of quantum gravity that attempts to explain the black hole entropy. Using quantum entropy function formalism we compute logarithmic corrections to the entropy of half BPS black holes in N=2 supersymmetric string theories. Our results allow us to test various proposals for the measure in the OSV formula, and we find agreement with the measure proposed by Denef and Moore if we assume their result to be valid at weak topological string coupling. Our analysis also gives the logarithmic corrections to the entropy of extremal Reissner-Nordstrom black holes in ordinary Einstein-Maxwell theory.
Ashoke Sen
Entanglement entropy of two-dimensional Anti-de Sitter black holes
Using the AdS/CFT correspondence we derive a formula for the entanglement entropy of the anti-de Sitter black hole in two spacetime dimensions. The leading term in the large black hole mass expansion of our formula reproduces exactly the Bekenstein-Hawking entropy S_{BH}, whereas the subleading term behaves as ln S_{BH}. This subleading term has the universal form typical for the entanglement entropy of physical systems described by effective conformal fields theories (e.g. one-dimensional statistical models at the critical point). The well-known form of the entanglement entropy for a two-dimensional conformal field theory is obtained as analytic continuation of our result and is related with the entanglement entropy of a black hole with negative mass.
Report on Characterization of U-10 wt.% Zr Alloy
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.
McKeown, J; Wall, M; Hsiung, L; Turchi, P
Improved oxidation sulfidation resistance of Fe-Cr-Ni alloys
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.
Natesan, K.; Baxter, D.J.
The oxidation resistance of binary and ternary zirconium alloys containing 0.5 to 5 wt% niobium and ternary additions of Sn, Cu, W, Mo, Sb, V, Ge, Pd, Pt, Fe, and Mn was studied in steam and air. The lowest oxidation rate was achieved with a Zr--1% Nb--1% Cu alloy. A study of the effect of heat treatment on the alloys showed that either a 24 hour anneal at 580 deg C, or cold-working of the material will result in good oxidation resistance. Some alloys containing high percentages of niobium (20-60 wt%) were examined. All the alloys were susceptible to non-uniform oxidation at long times, leading (in some instances) to cracking of the specimen. Such alloys are not considered reliable for use as structural materials involving long exposures to high temperature water or steam. The rate of hydrogen absorption by alloys containing small additions of niobium was very much less than that found for Zircaloy-2. (auth)
Cox, B.; Chadd, P.G.; Short, J.F.
Entropy and Free Energy of a Mobile Protein Loop in Explicit Water Srinath Cheluvaraja, Mihail Mihailescu, and Hagai Meirovitch*
Entropy and Free Energy of a Mobile Protein Loop in Explicit Water Srinath Cheluvaraja, Mihail of the absolute entropy, S (hence the absolute free energy F) is difficult because it depends on the entire at 300 K. As in paper I, we are mainly interested in entropy and free energy differences between the free
Meirovitch, Hagai
Absolute entropy and free energy of fluids using the hypothetical scanning method. I. Calculation of transition probabilities from local grand
Absolute entropy and free energy of fluids using the hypothetical scanning method. I. Calculation the absolute entropy and free energy from a Boltzmann sample generated by Monte Carlo, molecular dynamics for the free energy. We demonstrate that very good results for the entropy and the free energy can be obtained
1 Underwater 3D SLAM through Entropy Minimization J.M. Sez, A. Hogue, F. Escolano and M. Jenkin
1 Underwater 3D SLAM through Entropy Minimization J.M. Sáez, A. Hogue, F. Escolano and M. Jenkin Underwater 3D SLAM through Entropy Minimization J.M. Sáez*, A. Hogue**, F. Escolano* and M. Jenkin** Underwater 3D SLAM through Entropy Minimization *Robot Vision Group, Dept. de Ciencia de la Computación e
Escolano, Francisco
Translating z to alloy
Few tools are available to help with the difficult task of validating that a Z specification captures its intended meaning. One tool that has been proven to be useful for validating specifications is the Alloy Analyzer, an interactive tool for checking ...
Petra Malik; Lindsay Groves; Clare Lenihan
Quinary metallic glass alloys
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.
Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)
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.
Lin, X.; Johnson, W.L.
Multi-range force sensors utilizing shape memory alloys
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.
Varma, Venugopal K. (Knoxville, TN)
Models, Entropy and Information of Temporal Social Networks
Temporal social networks are characterized by {heterogeneous} duration of contacts, which can either follow a power-law distribution, such as in face-to-face interactions, or a Weibull distribution, such as in mobile-phone communication. Here we model the dynamics of face-to-face interaction and mobile phone communication by a reinforcement dynamics, which explains the data observed in these different types of social interactions. We quantify the information encoded in the dynamics of these networks by the entropy of temporal networks. Finally, we show evidence that human dynamics is able to modulate the information present in social network dynamics when it follows circadian rhythms and when it is interfacing with a new technology such as the mobile-phone communication technology.
Zhao, Kun; Bianconi, Ginestra
In the frame of Hamilton-Jacobi method, the back-reactions of the radiating particles together with the total entropy change of the whole system are investigated. The emission probability from this process is found to be equivalent to the null geodesic method. However its physical picture is more clear: the negative energy one of a virtual particle pair is absorbed by the black hole, resulting in the temperature, electric potential and angular velocity increase; then the black hole amount of heat, electric charge and angular momentum can spontaneously transfer to the positive energy particle; when obtaining enough energy, it can escape away to infinity, visible to distant observers. And this method can be applied to any sort of horizons and particles without a specific choice of (regular-across-the-horizon) coordinates.
Chikun Ding
Copper Alloy Corrosion in High Purity Feedwater: Admiralty Brass, Aluminum Brass, and 90/10 Copper/Nickel at 95 °C (203 °F)
Uncontrolled copper transport activity represents a potentially significant source of performance and reliability loss to fossil plants with mixed-metallurgy feedwater systems. Continuing utility experiences with severe copper fouling on high pressure (HP) turbines identified the need for fundamental research to improve control of copper corrosion in low pressure (LP) feedwater heater environments.
Corrosion Evaluation of Stellite Alloys 12 and 712
The High Level Waste Division requested the Materials Technology Section (MTS) to evaluate the use of Waukesha Metal 88 (WM88) and Stellite alloys 12 (S12) and 712 (S712) as materials of construction for slurry pumps. As candidate materials, WM88 was chosen for the tilt pad column bearings and S12 and S712 were selected for the impeller bearings. The Stellite alloys are cobalt-based alloys typically used for their resistance to both corrosion and wear. WM88 is noted for resistance to galling and seizing. These materials, however, had not been evaluated for use in high level radioactive waste, which have a high pH. A series of electrochemical corrosion tests were performed in support of this evaluation to determine the general corrosion rate and corrosion characteristics of these alloys. The tests were conducted at room temperature in simulated three waste tank environments. For WM88, the test solution was inhibited water, which is commonly used in the tank farm. For S12 and S712, the test solutions were a simulated Tank 8 waste solution and a 3 M sodium hydroxide solution. The general corrosion rates of all alloys in these solutions were less than 0.1 mils per year (mpy). The alloys displayed passive behavior in these solutions due to the protective nature of their oxides.
Mickalonis, J.I.
Development of vanadium base alloys for fusion first-wall/blanket applications
Vanadium alloys have been identified as a leading candidate material for fusion first-wall/blanket applications. Certain vanadium alloys exhibit favorable safety and environmental characteristics, good fabricability, high temperature and heat load capability, good compatibility with liquid metals and resistance to irradiation damage effects. The current focus is on vanadium alloys with (3-5)% Cr and (3-5)% Ti with a V-4Cr-4Ti alloy as the leading candidate. Preliminary results indicate that the crack-growth rates of certain alloys are not highly sensitive to irradiation. Results from the Dynamic Helium Charging Experiment (DHCE) which simulates fusion relevant helium/dpa ratios are similar to results from neutron irradiated material. This paper presents an overview of the recent results on the development of vanadium alloys for fusion first wall/blanket applications.
Smith, D.L.; Chung, H.M.; Loomis, B.A. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ., Sendai (Japan); Votinov, S. [Bochvar Institute of Inorganic Materials (Russia); VanWitzenburg, W. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands)
Development of high, stable-efficiency triple-junction a-Si alloy solar cells. Annual technical progress report, October 1995--October 1996
The overall objective of this amorphous silicon research program is to develop high efficiency a-Si solar cells and to develop and improve processes for large area deposition of a-Si solar cells and modules. The knowledge obtained and technologies demonstrated in this program will be incorporated into ECD`s continuous roll-to-roll deposition process to further enhance its photovoltaic manufacturing technology.
Deng, X.; Izu, M.; Jones, S.J.; Kopf, R. [Energy Conversion Devices, Troy, MI (United States)] [and others
Filler metal alloy for welding cast nickel aluminide alloys
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.
N=4 Superconformal Algebra and the Entropy of HyperKahler Manifolds
We study the elliptic genera of hyperKahler manifolds using the representation theory of N=4 superconformal algebra. We consider the decomposition of the elliptic genera in terms of N=4 irreducible characters, and derive the rate of increase of the multiplicities of half-BPS representations making use of Rademacher expansion. Exponential increase of the multiplicity suggests that we can associate the notion of an entropy to the geometry of hyperKahler manifolds. In the case of symmetric products of K3 surfaces our entropy agrees with the black hole entropy of D5-D1 system.
Tohru Eguchi; Kazuhiro Hikami
Thermal Hawking Broadening and Statistical Entropy of Black Hole Wave Packet
The quantum mechanical structure of Schwarzschild black hole is probed, in the mini super spacetime, by means of a non-singular minimal uncertainty Hartle-Hawking wave packet. The Compton width of the microstate probability distribution is translated into a thermal Hawking broadening of the mass spectrum. The statistical entropy is analytically calculated using the Fowler prescription. While the exact Bekenstein-Hawking entropy is recovered at the semi classical limit, the accompanying logarithmic tail gives rise to a Planck size minimal entropy black wave packet.
Aharon Davidson; Ben Yellin
Entanglement Entropy in Holographic P-Wave Superconductor/Insulator Model
We continue our study of entanglement entropy in the holographic superconducting phase transitions. In this paper we consider the holographic p-wave superconductor/insulator model, where as the back reaction increases, the transition is changed from second order to first order. We find that unlike the s-wave case, there is no additional first order transition in the superconducting phase. We calculate the entanglement entropy for two strip geometries. One is parallel to the super current, and the other is orthogonal to the super current. In both cases, we find that the entanglement entropy monotonically increases with respect to the chemical potential.
Rong-Gen Cai; Li Li; Li-Fang Li; Ru-Keng Su
What is the maximum rate at which entropy of a string can increase?
According to Susskind, a string falling toward a black hole spreads exponentially over the stretched horizon due to repulsive interactions of the string bits. In this paper such a string is modeled as a self-avoiding walk and the string entropy is found. It is shown that the rate at which information/entropy contained in the string spreads is the maximum rate allowed by quantum theory. The maximum rate at which the black hole entropy can increase when a string falls into a black hole is also discussed.
Ropotenko, Kostyantyn [State Administration of Communications, Ministry of Transport and Communications of Ukraine 22, Khreschatyk, 01001, Kyiv (Ukraine)
Ternary alloys of uranium and plutonium containing as the third element either molybdenum or zirconium are reported. Such alloys are particularly useful as reactor fuels in fast breeder reactors. The alloy contains from 2 to 25 at.% of molybdenum or zirconium, the balance being a combination of uranium and plutonium in the ratio of from 1 to 9 atoms of uranlum for each atom of plutonium. These alloys are prepared by melting the constituent elements, treating them at an elevated temperature for homogenization, and cooling them to room temperature, the rate of cooling varying with the oomposition and the desired phase structure. The preferred embodiment contains 12 to 25 at.% of molybdenum and is treated by quenching to obtain a body centered cubic crystal structure. The most important advantage of these alloys over prior binary alloys of both plutonium and uranium is the lack of cracking during casting and their ready machinability.
Waber, J.T.
Mold, flow, and economic considerations in high temperature precision casting
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 ...
Humbert, Matthew S
2013 JOM TEC_Final_v9.xlsx
Jan 1, 2013 ... Materials and Processes for Renewable Energy. Technologies. Materials in Nuclear Waste Disposal. Progress in High-Entropy Alloys.
Structures and Mechanical Properties
Mar 7, 2013... Refractory High-entropy Alloy: Chien-Chang Juan1; Jien-Wei Yeh1; ... The main wear mechanism was adhesive wear in deionized water, ...
Theoretical Studies of Hydrogen Storage Alloys.
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.
Jonsson, Hannes
Shape memory alloy actuator
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.
Heat-Resistant Alloys
Table 1Â Â Â Nominal compositions of selected heat-resistant nickel alloys...max 0.15 max Cu Gas turbines, rocket engines, nuclear applications N07750 Inconel X-750 15.5 73.0 â?¦ â?¦ 1.0 2.5 0.7 7.0 0.04 0.25 max Cu Gas turbine components, pressure vessels,
Titanium and Titanium Alloys
Table 15   Ranges and effects of some alloying elements used in titanium...% Effect on structure Aluminum 3â??8 α stabilizer Tin 2â??4 α stabilizer Vanadium 2â??15 β stabilizer Molybdenum 2â??15 β stabilizer Chromium 2â??12 β stabilizer Copper ~2 β stabilizer Zirconium 2â??5 α and β strengthener Silicon 0.05â??0.5 Improves creep resistance...
Duct and cladding alloy
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.
Korenko, Michael K. (Rockville, MD)
A Computationally Based Approach to Homogenizing Advanced Alloys
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.
Jablonski, P D; Cowen, C J
Ductile tungsten-nickel alloy and method for making same
The present invention is directed to a ductile, high-density tungsten-nickel alloy which possesses a tensile strength in the range of 100,000 to 140,000 psi and a tensile elongation of 3.1 to 16.5 percent in 1 inch at 25.degree.C. This alloy is prepared by the steps of liquid phase sintering a mixture of tungsten-0.5 to 10.0 weight percent nickel, heat treating the alloy at a temperature above the ordering temperature of approximately 970.degree.C. to stabilize the matrix phase, and thereafter rapidly quenching the alloy in a suitable liquid to maintain the matrix phase in a metastable, face-centered cubic, solid- solution of tungsten in nickel.
Snyder, Jr., William B. (Knoxville, TN)
Castability of HAYNES 282 Alloy
Austenitic Steel Oxidation in Steam: Alloy Composition and Surface ... Castability of Traditionally Wrought Ni-Based Superalloys for USC Steam Turbines.
Applications of Shape Memory Alloys
Mar 3, 2011 ... More than 50 years after the discovery of shape memory alloys, and after investments of millions of dollars, there are very few successful ...
Aluminum Alloys for Packaging III
Feb 1, 1998... of aluminum can stock, lid stock, and tab stock alloys; coatings; and their related applications to can, lid, and tab making could be presented.
Lightweight Alloys for Aerospace Application
C.R. Hutchinson, X. Fan, S.J. Pennycook and G.J. Shiflet. Improving Recrystallization Resistance in Wrought Aluminum Alloys with. Scandium Addition .
Alloy and Materials Preparation II
Mar 5, 2013 ... Copper-Based Multi-Component Alloys by Vacuum Distillation to Separate Copper Enriched Lead, Silver and Other Valuable Metals Research: ...
Surface Studies of HSLA [high strength low alloy] Steel after Electrochemical Corrosion in Supercritical CO{sub 2}-H{sub 2}O Environment
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.
Ziomek-Moroz, M. Holcomb, G. Tylczak, J Beck, J Fedkin, M. Lvov, S.
Precipitate Phases in Several High Temperature Shape Memory ...
About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Shape Memory Alloys. Presentation Title, Precipitate Phases in Several High ...
Effect of Environment and Microstructure on the High Temperature ...
EFFECT OF ENVIRONMENT AND MICROSTRUCTURE ON THE HIGH. TEMPERATURE BEHAVIOR OF ALLOY 718. E. Andrieu",. R. Cozar** and A. Pineau".
High Temperature Fatigue Life of Coated and Uncoated Valve ...
Symposium, Properties, Processing, and Performance of Steels and Ni-Based Alloys for Advanced Steam Conditions. Presentation Title, High Temperature ...
Production Evaluation of 718-ER Alloy - TMS
A fill-scale production trial was conducted to evaluate 718-ER in comparison with standard alloy 718. The processing characteristics of both alloys in.
Solid Solution Lithium Alloy Cermet Anodes
Solid Solution Lithium Alloy Cermet Anodes Thomas J.94720 USA Abstract Lithium-magnesium solid solution alloysHeating mixtures of lithium nitride and magnesium provides a
Richardson, Thomas J.; Chen, Guoying
TABLE OF CONTENTS Aluminum Alloys: Fabrication
Preparation of Al-Li Alloys by Molten Salts Electrolysis ..................................91. Jidong Li, Mingjie Zhang, Tingan Zhang, and Dan Li. Preparation of Al-Sc Alloys by ...
Proceedings of the Conference on Coal Feeding Systems, HeldWear Resistant Alloys for Coal Handling Equipment", proposalWear Resistant Alloys for Coal Handling Equi pment". The
Bhat, M.S.
Amorphous Aluminum Alloys—Synthesis and Stability
Recent innovations in metallic glasses have led to new alloy classes that may be vitrified and a re-examination of the key alloying factors influencing glass ...
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.
J.K. Wright; L.J. Carroll; C.J. Cabet; T. Lillo; J.K. Benz; J.A. Simpson; A. Chapman; R.N. Wright
Numerical Uncertainties in Simulation of Reversible Isentropic Processes and Entropy Conservation: Part II
The objectives of this study are 1) to provide the framework for an in-depth statistical analysis of the numerical uncertainties in the simulation of conservation of entropy, potential vorticity, and like properties under appropriate modeling ...
Donald R. Johnson; Allen J. Lenzen; Tom H. Zapotocny; Todd K. Schaack
An Entropy Approach to Tuning Weights and Smoothing in the Generalized Inversion
Weak constraint data assimilation involves a certain number of weighting and smoothing parameters. The authors present an approach to estimate them based on maximizing the entropy. Because application of this rigorous scheme to large-dimensional ...
Gennady A. Kivman; Alexandre L. Kurapov; Alina V. Guessen
Cloud and Water Vapor Feedbacks in a Vertical Energy-Balance Model with Maximum Entropy Production
A vertically one-dimensional model is developed with cloud fraction constrained by the maximum entropy production (MEP) principle. The model reasonably reproduces the global mean climate with its surface temperature, radiation and heat fluxes, ...
Biao Wang; Teruyuki Nakajima; Guangyu Shi
Energy and Enstrophy Spectra of Geostrophic Turbulent Flows Derived from a Maximum Entropy Principle
The principle of maximum entropy is used to obtain energy and enstrophy spectra as well as average relative vorticity fields in the context of geostrophic turbulence on a rotating sphere. In the unforced-undamped (inviscid) case, the maximization ...
W. T. M. Verkley; Peter Lynch
Optimising maximum power output and minimum entropy generation of Atkinson cycle using mutable smart bees algorithm
The purpose of this article is optimising maximum power output (MPO) and minimum entropy generation (MEG) of an Atkinson cycle as a multi-objective constraint thermodynamic problem by a new improved artificial bee colony algorithm which utilises 'mutable ...
Mofid Gorji; Ahmad Mozaffari; Sina Mohammadrezaei Noudeh
Examining Information Entropy Approaches as Wind Power Forecasting Performance Metrics: Preprint
In this paper, we examine the parameters associated with the calculation of the Renyi entropy in order to further the understanding of its application to assessing wind power forecasting errors.
Hodge, B. M.; Orwig, K.; Milligan, M.
Numerical Uncertainties in the Simulation of Reversible Isentropic Processes and Entropy Conservation
A challenge common to weather, climate, and seasonal numerical prediction is the need to simulate accurately reversible isentropic processes in combination with appropriate determination of sources/sinks of energy and entropy. Ultimately, this ...
Notes on the equality in SSA of entropy on CAR algebra
We prove a necessary an sufficient condition for the states which satisfy strong subadditivity of von Neumann entropy with equality on CAR algebra and we show an example when the equality holds but the state is not separable.
J. Pitrik; V. P. Belavkin
Hamiltonian surface shaping with information theory and exergy#47;entropy control for collective plume tracing
The goal of this paper is to design and analyse distributed decentralised control laws for a team of robots performing collective plume tracing based on Hamiltonian surface shaping, information theory, and exergy/entropy control. The process ... Keywords: Fisher information, Hamiltonian systems, collective plume tracing, collective systems, decentralised control, distributed control, entropy control, exergy control, information theory, kinetic control, robot collaboration, robot control, robot kinematics, robots, surface shaping
Rush D. Robinett, III; David G. Wilson
We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D Bjorken scenario, appropriate for the early longitudinal expansion stage of the collision. Going beyond the standard simplification of a massless ideal gas we consider a realistic equation of state consistently derived within a virial expansion. The EoS used is well in line with recent three-flavor QCD lattice data for the pressure, speed of sound, and interaction measure at nonzero temperature and vanishing chemical potential ($\\mu_{\\rm q} = 0$). The shear viscosity has been consistently calculated within this formalism using a kinetic approach in the ultra-relativistic regime with an explicit and systematic evaluation of the transport cross section as function of temperature. We investigate the influence of the viscosity and the initial condition, i.e. formation time, initial ...
Mattiello, Stefano
Observables and Microscopic Entropy of Higher Spin Black Holes
In the context of recently proposed holographic dualities between higher spin theories in AdS3 and 1+1-dimensional CFTs with W-symmetry algebras, we revisit the definition of higher spin black hole thermodynamics and the dictionary between bulk fields and dual CFT operators. We build a canonical formalism based on three ingredients: a gauge-invariant definition of conserved charges and chemical potentials in the presence of higher spin black holes, a canonical definition of entropy in the bulk, and a bulk-to-boundary dictionary aligned with the asymptotic symmetry algebra. We show that our canonical formalism shares the same formal structure as the so-called holomorphic formalism, but differs in the definition of charges and chemical potentials and in the bulk-to-boundary dictionary. Most importantly, we show that it admits a consistent CFT interpretation. We discuss the spin-2 and spin-3 cases in detail and generalize our construction to theories based on the hs[\\lambda] algebra, and on the sl(N,R) algebra for any choice of sl(2,R) embedding.
Geoffrey Compčre; Juan I. Jottar; Wei Song
Potential automotive uses of wrought magnesium alloys
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.
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)
Radiation resistant austenitic stainless steel alloys
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.
Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.
A theoretical examination of the growth and attenuation of acoustic and entropy waves in ideal MHD generators
Results of a theoretical investigation of the interaction between electromagnetic fields and acoustic and entropy waves in a partially ionized gas are presented. The effects of this interaction for combustion-driven magnetohydrodynamic (MHD) generators are provided in terms of nine frequency-dependent transmission and reflection coefficients. The important finding is that generators having certain configurations will be subjected to large increases in amplitude of at least one of the traveling waves, and thus lead to large fluctuations in plasma properties with a consequent degradation of generator performance. This is especially true for the downstream propagating temperature (entropy) fluctuation, which creates rather significant amounts of fluctuations in the acoustic (pressure) waves. Previous theoretical studies have indicated that the Faraday generators which are stable at low magnetic field strength may be unstable at high magnetic field strength. In this study, such adverse effect on stability is observed for both the Faraday and the DCW generators. The results were obtained at four different frequencies of perturbation varying from 1 to 1000 Hz.
Kulkarni, M.R.
Shape memory alloy thaw sensors
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.
Shahinpoor, Mohsen (Albuquerque, NM); Martinez, David R. (Albuquerque, NM)
A low melting point plutonium alloy useful as fuel is a homogeneous liquid metal fueled nuclear reactor is described. Vessels of tungsten or tantalum are useful to contain the alloy which consists essentially of from 10 to 30 atomic per cent copper and the balance plutonium and cerium. with the plutontum not in excess of 50 atomic per cent.
Local phase transformation in alloys during charged-particle irradiation
Among the various mechanisms and processes by which energetic irradiation can alter the phase stability of alloys, radiation-induced segregation is one of the most important phenomena. Radiation-induced segregation in alloys occurs as a consequence of preferential coupling between persistent fluxes of excess defects and solute atoms, leading to local enrichment or depletion of alloying elements. Thus, this phenomenon tends to drive alloy systems away from thermodynamic equilibrium, on a local scale. During charged-particle irradiations, the spatial nonuniformity in the defect production gives rise to a combination of persistent defect fluxes, near the irradiated surface and in the peak-damage region. This defect-flux combination can modify the alloy composition in a complex fashion, i.e., it can destabilize pre-existing phases, causing spatially- and temporally-dependent precipitation of new metastable phases. The effects of radiation-induced segregation on local phase transformations in Ni-based alloys during proton bombardment and high-voltage electron-microscope irradiation at elevated temperatures are discussed.
Lam, N.Q.; Okamoto, P.R.
Thermomechanical treatment of alloys
An article of an alloy of AISI 316 stainless steel is reduced in size to predetermined dimensions by cold working in repeated steps. Before the last reduction step the article is annealed by heating within a temperature range, specifically between 1010.degree. C. and 1038.degree. C. for a time interval between 90 and 60 seconds depending on the actual temperature. By this treatment the swelling under neutron bombardment by epithermal neutrons is reduced while substantial recrystallization does not occur in actual use for a time interval of at least of the order of 5000 hours.
Bates, John F. (Ogden, UT); Brager, Howard R. (Richland, WA); Paxton, Michael M. (Gaithersburg, MD)
Microstructure and Mechanical Property of Cu-40%Zn-0.5%Cr Alloy ...
Yield stress of extruded P/M Cu-40Zn-0.5Cr brass alloy at 773 K was 514.6 MPa, high value of 54.7% of the conventional P/M Cu60-Zn40 brass alloy at same ...
High-density Fuel Development for High Performance Research ...
Abstract Scope, High density UMo (7-12wt% Mo) fuel for high performance research ... High Energy X-ray Diffraction Study of Deformation Behavior of Alloy HT9.
Multi-fluid shocks in clusters of galaxies: entropy, sigma_ v-T, M-T and L_x-T scalings
The nonthermal phenomena in clusters of galaxies are considered in the context of the hierarchical model of cosmic structure formation by accretion and merging of the dark matter (DM) substructures.Accretion and merging processes produce large-scale gas shocks. The plasma shocks are expected to be collisionless. In the course of cluster's aggregation, the shocks, being the main gas-heating agent, generate turbulent magnetic fields and accelerate energetic particles via collisionless multi-fluid plasma relaxation processes. The intracluster gas heating and entropy production rate by a collisionless shock may differ significantly from that in a single-fluid collisional shock. Simple scaling relations for postshock ion temperature and entropy as functions of shock velocity in strong collisionless multi-fluid shocks are presented. We show that the multi-fluid nature of the collisionless shocks results in high gas compression, reduced entropy production and modified sigma_v-T, M-T and L_x-T scalings. The scaling i...
Bykov, A M
The nonthermal phenomena in clusters of galaxies are considered in the context of the hierarchical model of cosmic structure formation by accretion and merging of the dark matter (DM) substructures.Accretion and merging processes produce large-scale gas shocks. The plasma shocks are expected to be collisionless. In the course of cluster's aggregation, the shocks, being the main gas-heating agent, generate turbulent magnetic fields and accelerate energetic particles via collisionless multi-fluid plasma relaxation processes. The intracluster gas heating and entropy production rate by a collisionless shock may differ significantly from that in a single-fluid collisional shock. Simple scaling relations for postshock ion temperature and entropy as functions of shock velocity in strong collisionless multi-fluid shocks are presented. We show that the multi-fluid nature of the collisionless shocks results in high gas compression, reduced entropy production and modified sigma_v-T, M-T and L_x-T scalings. The scaling indexes estimated for a simple model of a strong accretion multi-fluid shock are generally consistent with observations. Soft X-ray and extreme ultraviolet photons dominate the emission of strong accretion shock precursors that appear as large-scale filaments. Magnetic fields, turbulence and energetic particles constitute the nonthermal components contributing into the pressure balance, energy transport and emission of clusters. Nonthermal emission of energetic particles could be a test to constrain the cluster properties.
A. M. Bykov
Titanium Alloys Production for High Temperature Applications
Lignocellulosic-Based Carbon Fibers from Biofuel Production Wastes · Magnesium Sheets Produced by Extrusion · Magnetite Formation Observed with TEM on ...
high temperature intergranular oxidation of alloy 718
Framatome ANP Fuel Division ; 10, rue J. Récamier ; 69456 Lyon Cedex, France. 2. Centre Inter-Universitaire de Recherche et d'Ingénierie des Matériaux ...