Sample records for melting includes graphite

  1. Self-Consistent-Field Study of Adsorption and Desorption Kinetics of Polyethylene Melts on Graphite and Comparison with Atomistic Simulations

    E-Print Network [OSTI]

    Doros N. Theodorou; Georgios G. Vogiatzis; Georgios Kritikos

    2015-02-20T23:59:59.000Z

    A method is formulated, based on combining self-consistent field theory with dynamically corrected transition state theory, for estimating the rates of adsorption and desorption of end-constrained chains (e.g. by crosslinks or entanglements) from a polymer melt onto a solid substrate. This approach is tested on a polyethylene/graphite system, where the whole methodology is parametrized by atomistically detailed molecular simulations. For short-chain melts, which can still be addressed by molecular dynamics simulations with reasonable computational resources, the self-consistent field approach gives predictions of the adsorption and desorption rate constants which are gratifyingly close to molecular dynamics estimates.

  2. Energy Saving Melting and Revert Reduction Technology: Aging of Graphitic Cast Irons and Machinability

    SciTech Connect (OSTI)

    Von L. Richards

    2012-09-19T23:59:59.000Z

    The objective of this task was to determine whether ductile iron and compacted graphite iron exhibit age strengthening to a statistically significant extent. Further, this effort identified the mechanism by which gray iron age strengthens and the mechanism by which age-strengthening improves the machinability of gray cast iron. These results were then used to determine whether age strengthening improves the machinability of ductile iron and compacted graphite iron alloys in order to develop a predictive model of alloy factor effects on age strengthening. The results of this work will lead to reduced section sizes, and corresponding weight and energy savings. Improved machinability will reduce scrap and enhance casting marketability. Technical Conclusions: ���¢�������¢ Age strengthening was demonstrated to occur in gray iron ductile iron and compacted graphite iron. ���¢�������¢ Machinability was demonstrated to be improved by age strengthening when free ferrite was present in the microstructure, but not in a fully pearlitic microstructure. ���¢�������¢ Age strengthening only occurs when there is residual nitrogen in solid solution in the Ferrite, whether the ferrite is free ferrite or the ferrite lamellae within pearlite. ���¢�������¢ Age strengthening can be accelerated by Mn at about 0.5% in excess of the Mn/S balance Estimated energy savings over ten years is 13.05 trillion BTU, based primarily on yield improvement and size reduction of castings for equivalent service. Also it is estimated that the heavy truck end use of lighter castings for equivalent service requirement will result in a diesel fuel energy savings of 131 trillion BTU over ten years.

  3. Preparation of graphitic articles

    DOE Patents [OSTI]

    Phillips, Jonathan; Nemer, Martin; Weigle, John C.

    2010-05-11T23:59:59.000Z

    Graphitic structures have been prepared by exposing templates (metal, metal-coated ceramic, graphite, for example) to a gaseous mixture that includes hydrocarbons and oxygen. When the template is metal, subsequent acid treatment removes the metal to yield monoliths, hollow graphitic structures, and other products. The shapes of the coated and hollow graphitic structures mimic the shapes of the templates.

  4. Graphite-based photovoltaic cells

    DOE Patents [OSTI]

    Lagally, Max (Madison, WI); Liu, Feng (Salt Lake City, UT)

    2010-12-28T23:59:59.000Z

    The present invention uses lithographically patterned graphite stacks as the basic building elements of an efficient and economical photovoltaic cell. The basic design of the graphite-based photovoltaic cells includes a plurality of spatially separated graphite stacks, each comprising a plurality of vertically stacked, semiconducting graphene sheets (carbon nanoribbons) bridging electrically conductive contacts.

  5. Coated graphite articles useful in metallurgical processes and method for making same

    DOE Patents [OSTI]

    Holcombe, Cressie E. (Knoxville, TN); Bird, Eugene L. (Knoxville, TN)

    1995-01-01T23:59:59.000Z

    Graphite articles including crucibles and molds used in metallurgical processes involving the melting and the handling of molten metals and alloys that are reactive with carbon when in a molten state and at process temperatures up to about 2000.degree. C. are provided with a multiple-layer coating for inhibiting carbon diffusion from the graphite into the molten metal or alloys. The coating is provided by a first coating increment of a carbide-forming metal on selected surfaces of the graphite, a second coating increment of a carbide forming metal and a refractory metal oxide, and a third coating increment of a refractory metal oxide. The second coating increment provides thermal shock absorbing characteristics to prevent delamination of the coating during temperature cycling. A wash coat of unstabilized zirconia or titanium nitride can be applied onto the third coating increment to facilitate release of melts from the coating.

  6. Systems and methods for forming defects on graphitic materials and curing radiation-damaged graphitic materials

    DOE Patents [OSTI]

    Ryu, Sunmin; Brus, Louis E.; Steigerwald, Michael L.; Liu, Haitao

    2012-09-25T23:59:59.000Z

    Systems and methods are disclosed herein for forming defects on graphitic materials. The methods for forming defects include applying a radiation reactive material on a graphitic material, irradiating the applied radiation reactive material to produce a reactive species, and permitting the reactive species to react with the graphitic material to form defects. Additionally, disclosed are methods for removing defects on graphitic materials.

  7. #include #include

    E-Print Network [OSTI]

    Campbell, Andrew T.

    process #12;#include #include pid_t pid = fork(); if (pid () failed */ } else if (pid == 0) { /* parent process */ } else { /* child process */ } #12;thread #12

  8. #include #include

    E-Print Network [OSTI]

    Poinsot, Laurent

    #include #include //Rappels : "getpid()" permet d'obtenir son propre pid // "getppid()" renvoie le pid du père d'un processus int main (void) { pid_t pid_fils; pid_fils = fork(); if(pid_fils==-1) { printf("Erreur de création du processus fils\

  9. Do Ag{sub n} (up to n = 8) clusters retain their identity on graphite? Insights from first-principles calculations including dispersion interactions

    SciTech Connect (OSTI)

    Singh, Akansha; Sen, Prasenjit, E-mail: prasen@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India)] [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India)] [Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India)

    2014-04-28T23:59:59.000Z

    Adsorption of pre-formed Ag{sub n} clusters for n = 1 ? 8 on a graphite substrate is studied within the density functional theory employing the vdW-DF2 functional to treat dispersion interactions. Top sites above surface layer carbon atoms turn out to be most favorable for a Ag adatom, in agreement with experimental observations. The same feature is observed for clusters of almost all sizes which have the lowest energies when the Ag atoms are positioned over top sites. Most gas phase isomers retain their structures over the substrate, though a couple of them undergo significant distortions. Energetics of the adsorption can be understood in terms of a competition between energy cost of disturbing Ag–Ag bonds in the cluster and energy gain from Ag–C interactions at the surface. Ag{sub 3} turns out to be an exceptional candidate in this regard that undergoes significant structural distortion and has only two of the Ag atoms close to surface C atoms in its lowest energy structure.

  10. Melt containment member

    DOE Patents [OSTI]

    Rieken, Joel R.; Heidloff, Andrew J.

    2014-09-09T23:59:59.000Z

    A tubular melt containment member for transient containment of molten metals and alloys, especially reactive metals and alloys, includes a melt-contacting layer or region that comprises an oxygen-deficient rare earth oxide material that is less reactive as compared to the counterpart stoichiometric rare earth oxide. The oxygen-deficient (sub-stoichiometric) rare earth oxide can comprise oxygen-deficient yttria represented by Y.sub.2O.sub.3-x wherein x is from 0.01 to 0.1. Use of the oxygen-deficient rare earth oxide as the melt-contacting layer or region material reduces reaction with the melt for a given melt temperature and melt contact time.

  11. Tomographic location of potential melt-bearing phenocrysts in lunar glass spherules

    SciTech Connect (OSTI)

    Ebel, D.S.; Fogel, R.A.; Rivers, M.L. (AMNH); (UC)

    2005-02-04T23:59:59.000Z

    Apollo 17 orange glass spherules contain olivine phenocrysts with melt inclusions from depth. Tomography (<2micron/pxl) of >200 spherules located 1 phenocryst. We will try to find melt inclusions and obtain original magma volatiles and compositions. In 1971, Apollo 17 astronauts collected a 10 cm soil sample (74220) comprised almost entirely of orange glass spherules. Below this, a double drive-tube core sampled a 68 cm thick horizon comprised of orange glass and black beads (crystallized equivalents of orange glass). Primitive lunar glass spherules (e.g.-A17 orange glasses) are thought to represent ejecta from lunar mare fire fountains. The fire-fountains were apparently driven by a combination of C-O gas exsolution from orange glass melt and the oxidation of graphite. Upon eruption, magmas lost their volatiles (e.g., S, CO, CO{sub 2}) to space. Evidence for volatile escape remains as volatile-rich coatings on the exteriors of many spherules. Moreover, it showed that Type I and II Fe-Ni-rich metal particles found within orange glass olivine phenocrysts, or free-floating in the glass itself, are powerful evidence for the volatile driving force for lunar fire fountains. More direct evidence for the volatile mechanism has yet to be uncovered. Issues remaining include: the exact composition of magmatic volatiles; the hypothesized existence of graphite in the magma; the oxygen fugacity of the magma and of the lunar interior. In 1996 reported a single {approx}450 micron, equant olivine phenocryst, containing four glassy melt inclusions (or inclusion cores), the largest {approx}30micron in size, in a thin section of the 74001/2 drill core. The melt is assumed to sample the parent magma of the lunar basalts at depth, evidenced by the S content of the inclusion (600 ppm) which is 400 ppm greater than that of the orange glass host. Such melts potentially contain a full complement of the volatile components of the parent magma, which can be analyzed by infrared spectroscopy. Although the A17 orange glass magma is thought to derive from {approx} 400 km depth, the calculations imply a 4 km depth of graphite oxidation (and melt saturation in C-O volatiles) during ascent. We have imaged several hundred similar orange glass spherules, from sample 74220,764, using synchrotron x-ray computer-aided microtomography (XRCMT). Our goals: (1) locate similar phenocrysts containing melt inclusions; (2) analyze phenocrysts to understand the evolution of the magma; (3) analyze melt and fluid inclusions using EPMA and FTIR to obtain direct evidence of magmatic volatiles and pristine bulk compositions.

  12. Modeling Fission Product Sorption in Graphite Structures

    SciTech Connect (OSTI)

    Szlufarska, Izabela [University of Wisconsin, Madison, WI (United States); Morgan, Dane [University of Wisconsin, Madison, WI (United States); Allen, Todd [University of Wisconsin, Madison, WI (United States)

    2013-04-08T23:59:59.000Z

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission products on each type of graphite site. The model will include multiple simultaneous adsorbing species, which will allow for competitive adsorption effects between different fission product species and O and OH (for modeling accident conditions).

  13. Oxidation Resistant Graphite Studies

    SciTech Connect (OSTI)

    W. Windes; R. Smith

    2014-07-01T23:59:59.000Z

    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  14. Development of lead-free copper alloy graphite castings. Annual report, January--December 1995

    SciTech Connect (OSTI)

    Rohatgi, P.K.

    1996-10-01T23:59:59.000Z

    The distribution of graphite particles in graphite containing copper alloy was further improved very significantly using several procedures and technological modifications. The developed techniques attacked the graphite distribution problem in two ways. Realizing that clustering of very fine (5um) graphite particles is one of the two major problems, a pretreatment process has been developed using aluminum powders to deagglomerate graphite particles. Along with this, a two-stage stirring technique was used to first incorporate and then to distribute uniformly the deagglomerated particles in the melt. During this year, based on these developments, several components were cast to evaluate the castability of Cu alloy-graphite melts. In addition, machinability tests were done to clearly established that addition of graphite particles improve the machinability of copper MMC alloys over and above that of monolithic copper alloys. The results show that the machining chip sizes and cutting forces of Cu alloys containing graphite particles are smaller than these of the corresponding monolithic Cu alloys. This clearly establishes that the presence of graphite particles in copper alloy improves the machinability in a fashion similar to lead additions to copper alloys. Centrifugal casting of shapes of different sizes appear to be a very attractive method for casting graphite containing copper alloys, since all the graphite particles (regardless of their distribution in the melt) are forced to segregate to the inner periphery of the castings where they impart a very desirable solid lubrication property for bushing and bearing use. A very large number of cylindrical elements of lead bearing copper alloys are now used for similar bearing bushing applications and the manufacturers of these type of bearings are under safety and health hazard pressure to remove lead. This year several parameters for centrifugal casting of copper graphite alloys have been established.

  15. Surface treated natural graphite as anode material for high-power Li-ion battery applications.

    SciTech Connect (OSTI)

    Liu, J.; Vissers, D. R.; Amine, K.; Barsukov, I. V.; Henry, F.; Doniger, J.; Chemical Engineering; Superior Graphite Co.

    2006-01-01T23:59:59.000Z

    High power application of Li-ion battery in hybrid electrical vehicles requires low cost and safe cell materials. Among the various carbon anode materials used in lithium ion batteries, natural graphite shows the most promise with advantages in performance and cost. However, natural graphite is not compatible with propylene carbonate (PC)-based electrolytes, which have a lower melting point and improved safety characteristics. The problem with it is that the molecules of propylene carbonate intercalate with Li+ into graphite, and that frequently leads to the exfoliation of the graphite matrix.

  16. Analysis of Feed Melting Procesess

    SciTech Connect (OSTI)

    Matyas, Josef; Hrma, Pavel R.; Kim, Dong-Sang

    2003-05-12T23:59:59.000Z

    An efficient waste-glass melter with a sustained, high-volume glass throughput will allow a smaller vitrification facility, a shorter lifecycle, and glass with a higher concentration of waste. The vitrification process of two feeds that exhibited different rates of conversion was studied using thermal analyses, including evolved gas analysis with volume-expansion monitoring. Quantitative X-ray diffraction and scanning electron microscopy were performed on quenched samples. The difference in the melting rates was attributed to different melt viscosities at the temperature at which the melt interfaces the cold cap. It was suggested that low viscosity destabilizes foam under the cold cap, thus enhancing the rate of melting.

  17. Graphite Technology Development Plan

    SciTech Connect (OSTI)

    W. Windes; T. Burchell; R. Bratton

    2007-09-01T23:59:59.000Z

    This technology development plan is designed to provide a clear understanding of the research and development direction necessary for the qualification of nuclear grade graphite for use within the Next Generation Nuclear Plant (NGNP) reactor. The NGNP will be a helium gas cooled Very High Temperature Reactor (VHTR) with a large graphite core. Graphite physically contains the fuel and comprises the majority of the core volume. Considerable effort will be required to ensure that the graphite performance is not compromised during operation. Based upon the perceived requirements the major data needs are outlined and justified from the perspective of reactor design, reatcor performance, or the reactor safety case. The path forward for technology development can then be easily determined for each data need. How the data will be obtained and the inter-relationships between the experimental and modeling activities will define the technology development for graphite R&D. Finally, the variables affecting this R&D program are discussed from a general perspective. Factors that can significantly affect the R&D program such as funding, schedules, available resources, multiple reactor designs, and graphite acquisition are analyzed.

  18. Forming gas treatment of lithium ion battery anode graphite powders

    DOE Patents [OSTI]

    Contescu, Cristian Ion; Gallego, Nidia C; Howe, Jane Y; Meyer, III, Harry M; Payzant, Edward Andrew; Wood, III, David L; Yoon, Sang Young

    2014-09-16T23:59:59.000Z

    The invention provides a method of making a battery anode in which a quantity of graphite powder is provided. The temperature of the graphite powder is raised from a starting temperature to a first temperature between 1000 and 2000.degree. C. during a first heating period. The graphite powder is then cooled to a final temperature during a cool down period. The graphite powder is contacted with a forming gas during at least one of the first heating period and the cool down period. The forming gas includes H.sub.2 and an inert gas.

  19. Recompressed exfoliated graphite articles

    DOE Patents [OSTI]

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2013-08-06T23:59:59.000Z

    This invention provides an electrically conductive, less anisotropic, recompressed exfoliated graphite article comprising a mixture of (a) expanded or exfoliated graphite flakes; and (b) particles of non-expandable graphite or carbon, wherein the non-expandable graphite or carbon particles are in the amount of between about 3% and about 70% by weight based on the total weight of the particles and the expanded graphite flakes combined; wherein the mixture is compressed to form the article having an apparent bulk density of from about 0.1 g/cm.sup.3 to about 2.0 g/cm.sup.3. The article exhibits a thickness-direction conductivity typically greater than 50 S/cm, more typically greater than 100 S/cm, and most typically greater than 200 S/cm. The article, when used in a thin foil or sheet form, can be a useful component in a sheet molding compound plate used as a fuel cell separator or flow field plate. The article may also be used as a current collector for a battery, supercapacitor, or any other electrochemical cell.

  20. Irradiation Creep in Graphite

    SciTech Connect (OSTI)

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13T23:59:59.000Z

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  1. Improved graphite furnace atomizer

    DOE Patents [OSTI]

    Siemer, D.D.

    1983-05-18T23:59:59.000Z

    A graphite furnace atomizer for use in graphite furnace atomic absorption spectroscopy is described wherein the heating elements are affixed near the optical path and away from the point of sample deposition, so that when the sample is volatilized the spectroscopic temperature at the optical path is at least that of the volatilization temperature, whereby analyteconcomitant complex formation is advantageously reduced. The atomizer may be elongated along its axis to increase the distance between the optical path and the sample deposition point. Also, the atomizer may be elongated along the axis of the optical path, whereby its analytical sensitivity is greatly increased.

  2. Diamond-graphite field emitters

    DOE Patents [OSTI]

    Valone, Steven M. (Santa Fe, NM)

    1997-01-01T23:59:59.000Z

    A field emission electron emitter comprising an electrode of diamond and a conductive carbon, e.g., graphite, is provided.

  3. Nondestructive evaluation of nuclear-grade graphite

    SciTech Connect (OSTI)

    Kunerth, D. C.; McJunkin, T. R. [Idaho National Laboratory, P.O. Box 1625, MS 2209, Idaho Falls, ID 83415-2209 (United States)

    2012-05-17T23:59:59.000Z

    The material of choice for the core of the high-temperature gas-cooled reactors being developed by the U.S. Department of Energy's Next Generation Nuclear Plant Program is graphite. Graphite is a composite material whose properties are highly dependent on the base material and manufacturing methods. In addition to the material variations intrinsic to the manufacturing process, graphite will also undergo changes in material properties resulting from radiation damage and possible oxidation within the reactor. Idaho National Laboratory is presently evaluating the viability of conventional nondestructive evaluation techniques to characterize the material variations inherent to manufacturing and in-service degradation. Approaches of interest include x-ray radiography, eddy currents, and ultrasonics.

  4. Electroless plating of graphite with copper and nickel

    SciTech Connect (OSTI)

    Caturla, F.; Molina, F.; Molina-Sabio, M.; Rodriguez-Reinoso, F. [Univ. de Alicante (Spain). Dept. de Quimica Inorganica; Esteban, A. [CIEMAT, Madrid (Spain)

    1995-12-01T23:59:59.000Z

    Decommissioning in the European Union of gas-cooled nuclear reactors using graphite as the moderator will generate a large amount of irradiated graphite as waste. Graphite is a radioactive waste of relatively low activity and consequently the options considered for the management of the waste may include: (i) incineration, (ii) ocean bed disposal, (iii) deep geological disposal, and (iv) shallow land burial. In case the last is the selected mode, an appropriate conditioning procedure is necessary before final disposal, by covering the graphite with a material avoiding or reducing the emission of radionuclides to its surrounding. This work analyses the possibility of conditioning graphite pieces (with a large proportion of pores of different sizes up to 100 {micro}m) with a metal coating of copper or nickel produced by electroless plating, with the aim of completely isolating the graphite from its surrounding. Electroless plating with copper results in a very large proportion of pores filled or covered, but a fraction of the pores remain in the graphite, which decreases with increasing thickness of metal deposit. Furthermore, the copper plating is permeable to liquids and consequently the graphite does not become completely isolated from the surrounding. The percentage of porosity filled or covered by nickel deposits is similar to copper, but they are not permeable to liquids, at least when the thickness is relatively high, and consequently the access of the liquids to the graphite is rather limited. However, when electroless plating with copper is followed by nickel deposition the graphite becomes isolated from the exterior.

  5. Heat exchanger using graphite foam

    DOE Patents [OSTI]

    Campagna, Michael Joseph; Callas, James John

    2012-09-25T23:59:59.000Z

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  6. Consequences of melt transport for uranium series disequilibrium in young lavas

    E-Print Network [OSTI]

    Spiegelman, Marc W.

    Consequences of melt transport for uranium series disequilibrium in young lavas Marc Spiegelman do not actu- ally include melt transport. Here we explore the be- haviour of short

  7. Noncovalently functionalized graphitic mesoporous carbon as a...

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

    functionalized graphitic mesoporous carbon as a stable support of Pt nanoparticles for oxygen reduction. Noncovalently functionalized graphitic mesoporous carbon as a stable...

  8. Spent graphite fuel element processing

    SciTech Connect (OSTI)

    Holder, N.D.; Olsen, C.W.

    1981-07-01T23:59:59.000Z

    The Department of Energy currently sponsors two programs to demonstrate the processing of spent graphite fuel elements. General Atomic in San Diego operates a cold pilot plant to demonstrate the processing of both US and German high-temperature reactor fuel. Exxon Nuclear Idaho Company is demonstrating the processing of spent graphite fuel elements from Rover reactors operated for the Nuclear Rocket Propulsion Program. This work is done at Idaho National Engineering Laboratory, where a hot facility is being constructed to complete processing of the Rover fuel. This paper focuses on the graphite combustion process common to both programs.

  9. Graphite electrode DC arc furnace. Innovative technology summary report

    SciTech Connect (OSTI)

    NONE

    1999-05-01T23:59:59.000Z

    The Graphite Electrode DC Arc Furnace (DC Arc) is a high-temperature thermal process, which has been adapted from a commercial technology, for the treatment of mixed waste. A DC Arc Furnace heats waste to a temperature such that the waste is converted into a molten form that cools into a stable glassy and/or crystalline waste form. Hazardous organics are destroyed through combustion or pyrolysis during the process and the majority of the hazardous metals and radioactive components are incorporated in the molten phase. The DC Arc Furnace chamber temperature is approximately 593--704 C and melt temperatures are as high as 1,500 C. The DC Arc system has an air pollution control system (APCS) to remove particulate and volatiles from the offgas. The advantage of the DC Arc is that it is a single, high-temperature thermal process that minimizes the need for multiple treatment systems and for extensive sorting/segregating of large volumes of waste. The DC Arc has the potential to treat a wide range of wastes, minimize the need for sorting, reduce the final waste volumes, produce a leach resistant waste form, and destroy organic contaminants. Although the DC arc plasma furnace exhibits great promise for treating the types of mixed waste that are commonly present at many DOE sites, several data and technology deficiencies were identified by the Mixed Waste Focus Area (MWFA) regarding this thermal waste processing technique. The technology deficiencies that have been addressed by the current studies include: establishing the partitioning behavior of radionuclides, surrogates, and hazardous metals among the product streams (metal, slag, and offgas) as a function of operating parameters, including melt temperature, plenum atmosphere, organic loading, chloride concentration, and particle size; demonstrating the efficacy of waste product removal systems for slag and metal phases; determining component durability through test runs of extended duration, evaluating the effect of feed composition variations on process operating conditions and slag product performance; and collecting mass balance and operating data to support equipment and instrument design.

  10. Macroscopic Properties of Restacked, Redox-Liquid Exfoliated Graphite and Graphite Mimics Produced in Bulk Quantities

    SciTech Connect (OSTI)

    Srivastava, Vikram K [ORNL; Quinlan, Ronald [ORNL; Agapov, Alexander L [ORNL; Dunlap, John R [ORNL; Nelson, Kimberly M [ORNL; Duranty, Edward R [ORNL; Sokolov, Alexei P [ORNL; Bhat, Gajanan [ORNL; Mays, Jimmy [ORNL

    2014-01-01T23:59:59.000Z

    The excellent properties exhibited by monolayer graphene have spurred the development of exfoliation techniques using bulk graphite to produce large quantities of pristine monolayer sheets. Development of simple chemistry to exfoliate and intercalate graphite and graphite mimics in large quantities is required for numerous applications. To determine the macroscopic behavior of restacked, exfoliated bulk materials, a systematic approach is presented using a simple, redox-liquid sonication process along to obtain large quantities of 2D and 3D hexagonally layered graphite, molybdenum disulfi de, and boron nitride, which are subsequently characterized to observe chemical and structural changes. For MoS 2 sonicated with the antioxidant sodium bisulfi te, results from Raman spectroscopy, X-ray diffraction, and electron microscopy indicate the presence of distorted phases from different polymorphs, and apparent nanotube structures in the bulk, restacked powder. Furthermore, using thermograviemtric analysis, the antioxidant enhances the resistance to oxidative degradation of MoS 2 , upon thermal treatment up to 900 C. The addition of the ionic antioxidant decreased dispersion stability in non-polar solvent, suggesting decreased compatibility with non-polar systems. Using simple chemical methods, the ability to generate tailored multidimensional layered materials with unique macroscopic properties is critical for numerous applications, including electrical devices, reinforced polymer composites, lithium ion capacitors, and chemical sensing.

  11. Brookhaven Graphite Research Reactor Workshop

    Broader source: Energy.gov [DOE]

    The Brookhaven Graphite Research Reactor (BGRR) was the first reactor built in the U.S. for peacetime atomic research following World War II.  Construction began in 1947 and the reactor started...

  12. Status of Initial Assessment of Physical and Mechanical Properties of Graphite Grades for NGNP Appkications

    SciTech Connect (OSTI)

    Strizak, Joe P [ORNL; Burchell, Timothy D [ORNL; Windes, Will [Idaho National Laboratory (INL)

    2011-12-01T23:59:59.000Z

    Current candidate graphite grades for the core structures of NGNP include grades NBG-17, NBG-18, PCEA and IG-430. Both NBG-17 and NBG-18 are manufactured using pitch coke, and are vibrationally molded. These medium grain products are produced by SGL Carbon SAS (France). Tayo Tanso (Japan) produces IG-430 which is a petroleum coke, isostatically molded, nuclear grade graphite. And PCEA is a medium grain, extruded graphite produced by UCAR Carbon Co. (USA) from petroleum coke. An experimental program has been initiated to develop physical and mechanical properties data for these current candidate graphites. The results will be judged against the requirements for nuclear grade graphites set forth in ASTM standard D 7219-05 "Standard Specification for Isotropic and Near-isotropic Nuclear Graphites". Physical properties data including thermal conductivity and coefficient of thermal expansion, and mechanical properties data including tensile, compressive and flexural strengths will be obtained using the established test methods covered in D-7219 and ASTM C 781-02 "Standard Practice for Testing Graphite and Boronated Graphite Components for High-Temperature Gas-Cooled Nuclear Reactors". Various factors known to effect the properties of graphites will be investigated. These include specimen size, spatial location within a graphite billet, specimen orientation (ag and wg) within a billet, and billet-to-billet variations. The current status of the materials characterization program is reported herein. To date billets of the four graphite grades have been procured, and detailed cut up plans for obtaining the various specimens have been prepared. Particular attention has been given to the traceability of each specimen to its spatial location and orientation within a billet.

  13. Physics of the Lindemann melting rule

    SciTech Connect (OSTI)

    Lawson, Andrew C [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    We investigate the thermodynamics of melting for 74 distinct chemical elements including several actinides and rare earths. We find that the observed melting points are consistent with a linear relationship between the correlation entropy of the liquid and the Grueneisen constant of the solid, and that the Lindemann rule is well obeyed for the elements with simple structures and less well obeyed for the less symmetric more open structures. No special assumptions are required to explain the melting points of the rare earths or light actinides.

  14. NGNP Graphite Testing and Qualification Specimen Selection Strategy

    SciTech Connect (OSTI)

    Robert Bratton

    2005-05-01T23:59:59.000Z

    The available grades of graphite for the NGNP are reviewed. A selection matrix is presented outlining the available grades for the NGNP graphite irradiation program based upon input from potential NGNP vendors, graphite manufactures, and graphite experts.

  15. Micro Joining of Aluminum Graphite Composites 

    E-Print Network [OSTI]

    Velamati, Manasa

    2012-07-16T23:59:59.000Z

    Advanced aluminum graphite composites have unique thermal properties due to opposing coefficients of thermal expansion of aluminum and graphite. The thermal and mechanical properties of such composites are anisotropic due to directional properties...

  16. Composition and method for brazing graphite to graphite

    DOE Patents [OSTI]

    Taylor, Albert J. (Ten Mile, TN); Dykes, Norman L. (Oak Ridge, TN)

    1984-01-01T23:59:59.000Z

    The present invention is directed to a brazing material for joining graphite structures that can be used at temperatures up to about 2800.degree. C. The brazing material formed of a paste-like composition of hafnium carbide and uranium oxide with a thermosetting resin. The uranium oxide is converted to uranium dicarbide during the brazing operation and then the hafnium carbide and uranium dicarbide form a liquid phase at a temperature about 2600.degree. C. with the uranium diffusing and vaporizing from the joint area as the temperature is increased to about 2800.degree. C. so as to provide a brazed joint consisting essentially of hafnium carbide. This brazing temperature for hafnium carbide is considerably less than the eutectic temperature of hafnium carbide of about 3150.degree. C. The brazing composition also incorporates the thermosetting resin so that during the brazing operation the graphite structures may be temporarily bonded together by thermosetting the resin so that machining of the structures to final dimensions may be completed prior to the completion of the brazing operation. The resulting brazed joint is chemically and thermally compatible with the graphite structures joined thereby and also provides a joint of sufficient integrity so as to at least correspond with the strength and other properties of the graphite.

  17. Graphite in Science and Nuclear Technique

    E-Print Network [OSTI]

    Zhmurikov, E I; Pokrovsky, A S; Harkov, D V; Dremov, V V; Samarin, S I

    2013-01-01T23:59:59.000Z

    The monograph is devoted to the application of graphite and graphite composites in science and technology. The structure and electrical properties, the technological aspects of production of high-strength synthetic graphites, the dynamics of the graphite destruction, traditionally used in the nuclear industry are discussed. It is focuses on the characteristics of graphitization and properties of graphite composites based on carbon isotope 13C. The book is based, generally, on the original results, and concentrated on the actual problems of application and testing of graphite materials in modern nuclear physics, in scientific and technical applications. For scientists and engineers specializing in nuclear physics and engineering, physics of nuclear reactors, condensed matter, for undergraduate, graduate and post-graduate students of universities physical specialties.

  18. Graphite in Science and Nuclear Technique

    E-Print Network [OSTI]

    E. I. Zhmurikov; I. A. Bubnenkov; A. S. Pokrovsky; D. V. Harkov; V. V. Dremov; S. I. Samarin

    2013-07-07T23:59:59.000Z

    The monograph is devoted to the application of graphite and graphite composites in science and technology. The structure and electrical properties, the technological aspects of production of high-strength synthetic graphites, the dynamics of the graphite destruction, traditionally used in the nuclear industry are discussed. It is focuses on the characteristics of graphitization and properties of graphite composites based on carbon isotope 13C. The book is based, generally, on the original results, and concentrated on the actual problems of application and testing of graphite materials in modern nuclear physics, in scientific and technical applications. For scientists and engineers specializing in nuclear physics and engineering, physics of nuclear reactors, condensed matter, for undergraduate, graduate and post-graduate students of universities physical specialties.

  19. Composition and method for brazing graphite to graphite

    DOE Patents [OSTI]

    Taylor, A.J.; Dykes, N.L.

    1982-08-10T23:59:59.000Z

    A brazing material is described for joining graphite structures that can be used up to 2800/sup 0/C. The brazing material is formed of a paste-like composition of hafnium carbide and uranium oxide with a thermosetting resin. The uranium oxide is converted to uranium dicarbide during the brazing operation and then the hafnium carbide and uranium dicarbide form a liquid phase at a temperature about 2600/sup 0/C with the uranium diffusing and vaporizing from the joint area as the temperature is increased to about 2800/sup 0/C so as to provide a brazed joint consisting essentially of hafnium carbide. The resulting brazed joint is chemically and thermally compatible with the graphite structures.

  20. AGC-3 Graphite Preirradiation Data Analysis Report

    SciTech Connect (OSTI)

    William Windes; David Swank; David Rohrbaugh; Joseph Lord

    2013-09-01T23:59:59.000Z

    This report describes the specimen loading order and documents all pre-irradiation examination material property measurement data for the graphite specimens contained within the third Advanced Graphite Capsule (AGC-3) irradiation capsule. The AGC-3 capsule is third in six planned irradiation capsules comprising the Advanced Graphite Creep (AGC) test series. The AGC test series is used to irradiate graphite specimens allowing quantitative data necessary for predicting the irradiation behavior and operating performance of new nuclear graphite grades to be generated which will ascertain the in-service behavior of the graphite for pebble bed and prismatic Very High Temperature Reactor (VHTR) designs. The general design of AGC-3 test capsule is similar to the AGC-2 test capsule, material property tests were conducted on graphite specimens prior to loading into the AGC-3 irradiation assembly. However the 6 major nuclear graphite grades in AGC-2 were modified; two previous graphite grades (IG-430 and H-451) were eliminated and one was added (Mersen’s 2114 was added). Specimen testing from three graphite grades (PCEA, 2114, and NBG-17) was conducted at Idaho National Laboratory (INL) and specimen testing for two grades (IG-110 and NBG-18) were conducted at Oak Ridge National Laboratory (ORNL) from May 2011 to July 2013. This report also details the specimen loading methodology for the graphite specimens inside the AGC-3 irradiation capsule. The AGC-3 capsule design requires "matched pair" creep specimens that have similar dose levels above and below the neutron flux profile mid-plane to provide similar specimens with and without an applied load. This document utilized the neutron flux profile calculated for the AGC-3 capsule design, the capsule dimensions, and the size (length) of the selected graphite and silicon carbide samples to create a stacking order that can produce "matched pairs" of graphite samples above and below the AGC-3 capsule elevation mid-point to provide specimens with similar neutron dose levels.

  1. INITIAL COMPARISON OF BASELINE PHYSICAL AND MECHANICAL PROPERTIES FOR THE VHTR CANDIDATE GRAPHITE GRADES

    SciTech Connect (OSTI)

    Carroll, Mark C

    2014-09-01T23:59:59.000Z

    High-purity graphite is the core structural material of choice in the Very High Temperature Reactor (VHTR) design, a graphite-moderated, helium-cooled configuration that is capable of producing thermal energy for power generation as well as process heat for industrial applications that require temperatures higher than the outlet temperatures of present nuclear reactors. The Baseline Graphite Characterization Program is endeavoring to minimize the conservative estimates of as-manufactured mechanical and physical properties in nuclear-grade graphites by providing comprehensive data that captures the level of variation in measured values. In addition to providing a thorough comparison between these values in different graphite grades, the program is also carefully tracking individual specimen source, position, and orientation information in order to provide comparisons both in specific properties and in the associated variability between different lots, different billets, and different positions from within a single billet. This report is a preliminary comparison between each of the grades of graphite that are considered “candidate” grades from four major international graphite producers. These particular grades (NBG-18, NBG-17, PCEA, IG-110, and 2114) are the major focus of the evaluations presently underway on irradiated graphite properties through the series of Advanced Graphite Creep (AGC) experiments. NBG-18, a medium-grain pitch coke graphite from SGL from which billets are formed via vibration molding, was the favored structural material in the pebble-bed configuration. NBG-17 graphite from SGL is essentially NBG-18 with the grain size reduced by a factor of two. PCEA, petroleum coke graphite from GrafTech with a similar grain size to NBG-17, is formed via an extrusion process and was initially considered the favored grade for the prismatic layout. IG-110 and 2114, from Toyo Tanso and Mersen (formerly Carbone Lorraine), respectively, are fine-grain grades produced via an isomolding process. An analysis of the comparison between each of these grades will include not only the differences in fundamental and statistically-significant individual strength levels, but also the differences in variability in properties within each of the grades that will ultimately provide the basis for the prediction of in-service performance. The comparative performance of the different types of nuclear-grade graphites will continue to evolve as thousands more specimens are fully characterized from the numerous grades of graphite being evaluated.

  2. Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

    SciTech Connect (OSTI)

    Zhamu, Aruna; Jang, Bor Z.

    2014-06-17T23:59:59.000Z

    A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

  3. Modeling pulsed-laser melting of embedded semiconductor nanoparticles

    E-Print Network [OSTI]

    Sawyer, C.A.

    2012-01-01T23:59:59.000Z

    Pulsed-laser melting (PLM) is commonly used to achieve athe size evolution during PLM of nanoparticles con?ned in aextended to include the PLM process. The PLM model includes

  4. Uranium Oxide Aerosol Transport in Porous Graphite

    SciTech Connect (OSTI)

    Blanchard, Jeremy; Gerlach, David C.; Scheele, Randall D.; Stewart, Mark L.; Reid, Bruce D.; Gauglitz, Phillip A.; Bagaasen, Larry M.; Brown, Charles C.; Iovin, Cristian; Delegard, Calvin H.; Zelenyuk, Alla; Buck, Edgar C.; Riley, Brian J.; Burns, Carolyn A.

    2012-01-23T23:59:59.000Z

    The objective of this paper is to investigate the transport of uranium oxide particles that may be present in carbon dioxide (CO2) gas coolant, into the graphite blocks of gas-cooled, graphite moderated reactors. The transport of uranium oxide in the coolant system, and subsequent deposition of this material in the graphite, of such reactors is of interest because it has the potential to influence the application of the Graphite Isotope Ratio Method (GIRM). The GIRM is a technology that has been developed to validate the declared operation of graphite moderated reactors. GIRM exploits isotopic ratio changes that occur in the impurity elements present in the graphite to infer cumulative exposure and hence the reactor’s lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.

  5. Stable aqueous dispersions of graphitic nanoplatelets via the reduction of exfoliated graphite oxide in the presence of poly(sodium

    E-Print Network [OSTI]

    Stable aqueous dispersions of graphitic nanoplatelets via the reduction of exfoliated graphite be prepared via an exfoliation/in-situ reduction of graphite oxide in the presence of poly(sodium 4 prepare graphite nanoplatelets via the chemical reduction of exfoliated graphite oxide nanoplatelets

  6. Graphitized-carbon fiber/carbon char fuel

    DOE Patents [OSTI]

    Cooper, John F. (Oakland, CA)

    2007-08-28T23:59:59.000Z

    A method for recovery of intact graphitic fibers from fiber/polymer composites is described. The method comprises first pyrolyzing the graphite fiber/polymer composite mixture and then separating the graphite fibers by molten salt electrochemical oxidation.

  7. Nuclear Graphite -Fission Reactor Brief Outline of Experience and

    E-Print Network [OSTI]

    McDonald, Kirk

    Nuclear Graphite - Fission Reactor Brief Outline of Experience and Understanding Professor Barry J · Physical Changes ­ to Polycrystalline Graphite due to Fast Neutron Damage and Radiolytic Oxidation ­ Provided channels for control rods and coolant gas · Neutron Shield ­ Boronated graphite · Thermal columns

  8. Graphite Reactor | ornl.gov

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental AssessmentsGeoffrey(SC)Graphite Reactor 'In the early, desperate

  9. Quantum modelling of hydrogen chemisorption on graphene and graphite

    SciTech Connect (OSTI)

    Karlický, František, E-mail: frantisek.karlicky@upol.cz [Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, T?. 17. listopadu 12, 771 46 Olomouc (Czech Republic)] [Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, T?. 17. listopadu 12, 771 46 Olomouc (Czech Republic); Lepetit, Bruno, E-mail: bruno.lepetit@irsamc.ups-tlse.fr; Lemoine, Didier, E-mail: didier.lemoine@irsamc.ups-tlse.fr [Laboratoire Collisions Agrégats Réactivité, IRSAMC and UMR5589 du CNRS, Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse cedex (France)] [Laboratoire Collisions Agrégats Réactivité, IRSAMC and UMR5589 du CNRS, Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse cedex (France)

    2014-03-28T23:59:59.000Z

    The chemisorption of hydrogen on graphene or graphite is studied within a quantum formalism involving a subsystem coupled to a phonon bath. The subsystem includes the hydrogen atom approaching the surface perpendicularly right on top of a carbon atom which puckers out of the surface. The bath includes the acoustic and optical phonon modes vibrating perpendicularly to the surface. Couplings between subsystem and bath are obtained with a periodic density functional theory calculation. Trapping probabilities are obtained as a function of the hydrogen atom kinetic energy. These results are discussed in the light of the experimental hydrogenation studies performed on graphite by Zecho et al. [J. Chem. Phys. 117, 8486 (2002)] and on graphene by Haberer et al. [Adv. Mater. 23, 4497 (2011)].

  10. PIA - 10th International Nuclear Graphite Specialists Meeting...

    Broader source: Energy.gov (indexed) [DOE]

    10th International Nuclear Graphite Specialists Meeting registration web site PIA - 10th International Nuclear Graphite Specialists Meeting registration web site More Documents &...

  11. Exfoliation of Graphite Oxide in Propylene Carbonate and Thermal

    E-Print Network [OSTI]

    Exfoliation of Graphite Oxide in Propylene Carbonate and Thermal Reduction of the Resulting Chemical Society ABSTRACT Graphite oxide was exfoliated and dispersed in propylene carbonate (PC) by bath

  12. Polyelectrolyte-Induced Reduction of Exfoliated Graphite Oxide...

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

    Reduction of Exfoliated Graphite Oxide: A Facile Route to Synthesis of Soluble Graphene Nanosheets. Polyelectrolyte-Induced Reduction of Exfoliated Graphite Oxide: A Facile...

  13. Investigations of Graphite Current Collectors and Metallic Lithium...

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

    Graphite Current Collectors and Metallic Lithium Anodes Investigations of Graphite Current Collectors and Metallic Lithium Anodes Presentation from the U.S. DOE Office of Vehicle...

  14. Establish and Expand Commercial Production of Graphite Anode...

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

    and Expand Commercial Production of Graphite Anode Materials for High Performance Lithium-ion Batteries Establish and Expand Commercial Production of Graphite Anode Materials...

  15. BGRR-048, Rev. C Brookhaven Graphite Research Reactor

    E-Print Network [OSTI]

    BGRR-048, Rev. C Brookhaven Graphite Research Reactor Decommissioning Project DRAFT CANAL AND WATER ....................................................................................... 1 2.2 Brookhaven Graphite Research Reactor

  16. Inhibition of Oxidation in Nuclear Graphite

    SciTech Connect (OSTI)

    Phil Winston; James W. Sterbentz; William E. Windes

    2013-10-01T23:59:59.000Z

    Graphite is a fundamental material of high temperature gas cooled nuclear reactors, providing both structure and neutron moderation. Its high thermal conductivity, chemical inertness, thermal heat capacity, and high thermal structural stability under normal and off normal conditions contribute to the inherent safety of these reactor designs. One of the primary safety issues for a high temperature graphite reactor core is the possibility of rapid oxidation of the carbon structure during an off normal design basis event where an oxidizing atmosphere (air ingress) can be introduced to the hot core. Although the current Generation IV high temperature reactor designs attempt to mitigate any damage caused by a postualed air ingress event, the use of graphite components that inhibit oxidation is a logical step to increase the safety of these reactors. Recent experimental studies of graphite containing between 5.5 and 7 wt% boron carbide (B4C) indicate that oxidation is dramatically reduced even at prolonged exposures at temperatures up to 900°C. The proposed addition of B4C to graphite components in the nuclear core would necessarily be enriched in B-11 isotope in order to minimize B-10 neutron absorption and graphite swelling. The enriched boron can be added to the graphite during billet fabrication. Experimental oxidation rate results and potential applications for borated graphite in nuclear reactor components will be discussed.

  17. Thermal and electrical conduction in the compaction direction of exfoliated graphite

    E-Print Network [OSTI]

    Chung, Deborah D.L.

    Thermal and electrical conduction in the compaction direction of exfoliated graphite in the compaction direction of graphite-flake-based exfoliated graphite have been decoupled. The compact Exfoliated graphite is elongated graphite particles obtained by the exfoliation (typically involving rapid

  18. AGC-2 Graphite Preirradiation Data Analysis Report

    SciTech Connect (OSTI)

    William Windes; W. David Swank; David Rohrbaugh; Joseph Lord

    2013-08-01T23:59:59.000Z

    This report described the specimen loading order and documents all pre-irradiation examination material property measurement data for the graphite specimens contained within the second Advanced Graphite Capsule (AGC-2) irradiation capsule. The AGC-2 capsule is the second in six planned irradiation capsules comprising the Advanced Graphite Creep (AGC) test series. The AGC test series is used to irradiate graphite specimens allowing quantitative data necessary for predicting the irradiation behavior and operating performance of new nuclear graphite grades to be generated which will ascertain the in-service behavior of the graphite for pebble bed and prismatic Very High Temperature Reactor (VHTR) designs. Similar to the AGC-1 specimen pre-irradiation examination report, material property tests were conducted on specimens from 18 nuclear graphite types but on an increased number of specimens (512) prior to loading into the AGC-2 irradiation assembly. All AGC-2 specimen testing was conducted at Idaho National Laboratory (INL) from October 2009 to August 2010. This report also details the specimen loading methodology for the graphite specimens inside the AGC-2 irradiation capsule. The AGC-2 capsule design requires “matched pair” creep specimens that have similar dose levels above and below the neutron flux profile mid-plane to provide similar specimens with and without an applied load. This document utilized the neutron flux profile calculated for the AGC-2 capsule design, the capsule dimensions, and the size (length) of the selected graphite and silicon carbide samples to create a stacking order that can produce “matched pairs” of graphite samples above and below the AGC-2 capsule elevation mid-point to provide specimens with similar neutron dose levels.

  19. Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube

    DOE Patents [OSTI]

    Zhang, Zhiqiang (Lexington, KY); Lockwood, Frances E. (Georgetown, KY)

    2008-03-25T23:59:59.000Z

    A fluid media such as oil or water, and a selected effective amount of carbon nanomaterials necessary to enhance the thermal conductivity of the fluid. One of the preferred carbon nanomaterials is a high thermal conductivity graphite, exceeding that of the neat fluid to be dispersed therein in thermal conductivity, and ground, milled, or naturally prepared with mean particle size less than 500 nm, and preferably less than 200 nm, and most preferably less than 100 nm. The graphite is dispersed in the fluid by one or more of various methods, including ultrasonication, milling, and chemical dispersion. Carbon nanotubes with graphitic structure is another preferred source of carbon nanomaterial, although other carbon nanomaterials are acceptable. To confer long term stability, the use of one or more chemical dispersants is preferred. The thermal conductivity enhancement, compared to the fluid without carbon nanomaterial, is proportional to the amount of carbon nanomaterials (carbon nanotubes and/or graphite) added.

  20. Melt Rate Improvement for DWPF MB3: Foaming Theory and Mitigation Techniques

    SciTech Connect (OSTI)

    Peeler, D.K.

    2001-07-24T23:59:59.000Z

    The objective of this research is to enhance the basic understanding of the role of glass chemistry, including the chemical kinetics of pre-melting, solid state reactions, batch melting, and the reaction pathways in glass and/or acid addition strategy changes on the overall melting process for the Defense Waste Processing Facility (DWPF) Macrobatch 3 (MB3).

  1. Superconductivity in graphite intercalation compounds

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

    Smith, Robert P. [Univ. of Cambridge (United Kingdom); Dean, Mark P. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Weller, Thomas E. [Univ. College of London (United Kingdom); Howard, Christopher A. [Univ. College of London (United Kingdom); Rahnejat, Kaveh C. [Univ. College of London (United Kingdom); Saxena, Siddharth S. [Univ. of Cambridge (United Kingdom); Ellerby, Mark [Univ. College of London (United Kingdom)

    2015-07-01T23:59:59.000Z

    The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s This paper recontextualizes the field in light of the discovery of superconductivity in CaC? and YbC? in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  2. Superconductivity in graphite intercalation compounds

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

    Smith, Robert P.; Dean, Mark P. M.; Weller, Thomas E.; Howard, Christopher A.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-07-01T23:59:59.000Z

    The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s This paper recontextualizes the field in light of the discovery of superconductivity in CaC? and YbC? in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes aremore »most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.« less

  3. Electron beam melting of charge based on titanium sponge

    SciTech Connect (OSTI)

    Tikhonovsky, A.L.; Tikhonovsky, K.A. [JS Co FIKO, Kiev (Ukraine)

    1995-12-31T23:59:59.000Z

    An experience of 0.8 MW consumable box melting furnace operation and theoretical simulation have led to the further development of the FIKO plant under construction on the base of melting of two consumable box-like bullets which move opposite each other and form narrow heated space between melted butt ends. It allows to reduce vaporization, spatter and radiation losses by several times and to reach two times increase in melting rate and 99%(97%) yield for c.p. titanium (alloys) without furnace power add. Future furnace design will provide the optimum protection of vacuum pumps against chlorides, the safety when melting titanium sponge and will permit hot ingots to move to the special furnace for EB surface conditioning. The maximum productivity is to be 18,000 t/year. The furnace can be used for the manufacture of aluminum-, copper-, iron-, nickel-, tungsten-based alloys and others of any charge including salvage.

  4. Polymer graphite composite anodes for Li-ion batteries

    E-Print Network [OSTI]

    Popov, Branko N.

    Polymer graphite composite anodes for Li-ion batteries Basker Veeraraghavan, Bala Haran, Ralph for the graphite particles by in-situ polymerization #12;Experimental Preparation of PPy/Graphite composites Dropwise addition of pyrrole into aqueous slurry of graphite at 0 °C with nitric acid acting as an oxidizer

  5. Method for molding threads in graphite panels

    DOE Patents [OSTI]

    Short, W.W.; Spencer, C.

    1994-11-29T23:59:59.000Z

    A graphite panel with a hole having a damaged thread is repaired by drilling the hole to remove all of the thread and making a new hole of larger diameter. A bolt with a lubricated thread is placed in the new hole and the hole is packed with graphite cement to fill the hole and the thread on the bolt. The graphite cement is cured, and the bolt is unscrewed therefrom to leave a thread in the cement which is at least as strong as that of the original thread. 8 figures.

  6. Method for molding threads in graphite panels

    DOE Patents [OSTI]

    Short, William W. (Livermore, CA); Spencer, Cecil (Silverton, OR)

    1994-01-01T23:59:59.000Z

    A graphite panel (10) with a hole (11) having a damaged thread (12) is repaired by drilling the hole (11) to remove all of the thread and make a new hole (13) of larger diameter. A bolt (14) with a lubricated thread (17) is placed in the new hole (13) and the hole (13) is packed with graphite cement (16) to fill the hole and the thread on the bolt. The graphite cement (16) is cured, and the bolt is unscrewed therefrom to leave a thread (20) in the cement (16) which is at least as strong as that of the original thread (12).

  7. Superhydrophilic graphite surfaces and water-dispersible graphite colloids by electrochemical exfoliation

    SciTech Connect (OSTI)

    Li, Yueh-Feng [Department of Chemical and Materials Engineering, National Central University, Jhongli, 320 Taiwan (China)] [Department of Chemical and Materials Engineering, National Central University, Jhongli, 320 Taiwan (China); Chen, Shih-Ming; Lai, Wei-Hao [Materials and Chemical Research Laboratories, Industrial Technology Research Institute, Chutung, Hsinchu, 31040 Taiwan (China)] [Materials and Chemical Research Laboratories, Industrial Technology Research Institute, Chutung, Hsinchu, 31040 Taiwan (China); Sheng, Yu-Jane [Department of Chemical Engineering, National Taiwan University, Taipei, 106 Taiwan (China)] [Department of Chemical Engineering, National Taiwan University, Taipei, 106 Taiwan (China); Tsao, Heng-Kwong [Department of Chemical and Materials Engineering, Department of Physics, National Central University, Jhongli, 320 Taiwan (China)] [Department of Chemical and Materials Engineering, Department of Physics, National Central University, Jhongli, 320 Taiwan (China)

    2013-08-14T23:59:59.000Z

    Superhydrophilic graphite surfaces and water-dispersible graphite colloids are obtained by electrochemical exfoliation with hydrophobic graphite electrodes. Such counterintuitive characteristics are caused by partial oxidation and investigated by examining both graphite electrodes and exfoliated particles after electrolysis. The extent of surface oxidation can be explored through contact angle measurement, scanning electron microscope, electrical sheet resistance, x-ray photoelectron spectroscopy, zeta-potential analyzer, thermogravimetric analysis, UV-visible, and Raman spectroscopy. The degree of wettability of the graphite anode can be altered by the electrolytic current and time. The water contact angle declines generally with increasing the electrolytic current or time. After a sufficient time, the graphite anode becomes superhydrophilic and its hydrophobicity can be recovered by peeling with adhesive tape. This consequence reveals that the anodic graphite is oxidized by oxygen bubbles but the oxidation just occurs at the outer layers of the graphite sheet. Moreover, the characteristics of oxidation revealed by UV peak shift, peak ratio between D and G bands, and negative zeta-potential indicate the presence of graphite oxide on the outer shell of the exfoliated colloids. However, thermogravimetric analysis for the extent of decomposition of oxygen functional groups verifies that the amount of oxygen groups is significantly less than that of graphite oxide prepared via Hummer method. The structure of this partially oxidized graphite may consist of a graphite core covered with an oxidized shell. The properties of the exfoliated colloids are also influenced by pH of the electrolytic solution. As pH is increased, the extent of oxidation descends and the thickness of oxidized shell decreases. Those results reveal that the degree of oxidation of exfoliated nanoparticles can be manipulated simply by controlling pH.

  8. Laboratory for Characterization of Irradiated Graphite

    SciTech Connect (OSTI)

    Karen A. Moore

    2010-03-01T23:59:59.000Z

    The newly completed Idaho National Laboratory (INL) Carbon Characterization Laboratory (CCL) is located in Labs C19 and C20 of the Idaho National Laboratory Research Center (IRC). The CCL was established under the Next Generation Nuclear Plant (NGNP) Project to support graphite and ceramic composite research and development activities. The research is in support of the Advanced Graphite Creep (AGC) experiment — a major material irradiation experiment within the NGNP Graphite program. The CCL is designed to characterize and test low activated irradiated materials such as high purity graphite, carbon-carbon composites, and silicon-carbide composite materials. The laboratory is fully capable of characterizing material properties for both irradiated and nonirradiated materials.

  9. Pyrolytic graphite production : automation of material placement

    E-Print Network [OSTI]

    Olle, Chase R

    2014-01-01T23:59:59.000Z

    This research examines the process and challenges associated with the addition of an autonomous transfer robot to a manufacturing line for AvCarb Material Solutions for use in production of pyrolytic graphite. Development ...

  10. Immobilization of Rocky Flats Graphite Fines Residue

    SciTech Connect (OSTI)

    Rudisill, T.S.

    1999-04-06T23:59:59.000Z

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  11. Core-melt source reduction system

    DOE Patents [OSTI]

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1995-04-25T23:59:59.000Z

    A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results. 4 figs.

  12. Core-melt source reduction system

    DOE Patents [OSTI]

    Forsberg, Charles W. (Oak Ridge, TN); Beahm, Edward C. (Oak Ridge, TN); Parker, George W. (Concord, TN)

    1995-01-01T23:59:59.000Z

    A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results.

  13. High pressure melt ejection

    SciTech Connect (OSTI)

    Tarbell, W.W.; Brockmann, J.E.; Pilch, M.

    1983-01-01T23:59:59.000Z

    Recent probabilistic risk assessments have identified the potential for reactor pressure vessel failure while the reactor coolant system is at elevated pressure. The analyses postulate that the blowdown of steam and hydrogen into the reactor cavity will cause the core material to be swept from the cavity region into the containment building. The High Pressure Melt Streaming (HIPS) program is an experimental study of the high pressure ejection of molten material and subsequent interactions within a concrete cavity. The program focuses on using prototypic system conditions and scaled models of reactor geometries to accurately simulate the ex-vessel processes during high-pressure accident sequences. Scaling analyses of the experiment show that the criteria established for core debris removal from the cavity are met or exceeded. Tests are performed at two scales, representing 1/10th and 1/20th linear reproductions of the Zion reactor plant. Results of the 1/20th scale tests are presented.

  14. Behavior of melts during softening and melting down of iron ore sinter under load

    SciTech Connect (OSTI)

    Cho, Y.H. [Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of)

    1995-12-01T23:59:59.000Z

    In order to achieve effective operation in the blast furnace, the distribution control and quality improvement of burden materials are very important. In spite of the difficulties in obtaining suitable samples and making direct observation, significant progress including the placement of probes into the stack, tuyere drilling and laboratory simulation studies has been made. Investigation of the behavior of melts during softening and melting down was carried out in the temperature range of 800 C to 1,515 C. In this report, emphasis is given to investigating the mineral formation and properties of melts during softening and melting down of the iron ore sinter. Sized coke layers were placed above and below the sample to maintain uniform upward flow of gas and insure a smooth downward flow of melts. When the temperature of the sample reached the set point during the test the power was shut off and the sample was cooled in the furnace air. The weight, the height, porosity and contraction of each sample were measured. Chemical composition, observation of microstructures, SEM analysis and X-ray diffraction analysis were conducted. Results are presented.

  15. Low-melting point heat transfer fluid

    DOE Patents [OSTI]

    Cordaro, Joseph Gabriel (Oakland, CA); Bradshaw, Robert W. (Livermore, CA)

    2010-11-09T23:59:59.000Z

    A low-melting point, heat transfer fluid made of a mixture of five inorganic salts including about 29.1-33.5 mol % LiNO.sub.3, 0-3.9 mol % NaNO.sub.3, 2.4-8.2 mol % KNO.sub.3, 18.6-19.9 mol % NaNO.sub.2, and 40-45.6 mol % KNO.sub.2. These compositions can have liquidus temperatures below 80.degree. C. for some compositions.

  16. Method of producing exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

    DOE Patents [OSTI]

    Zhamu, Aruna (Centerville, OH); Shi, Jinjun (Columbus, OH); Guo, Jiusheng (Centerville, OH); Jang, Bor Z. (Centerville, OH)

    2010-11-02T23:59:59.000Z

    The present invention provides a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

  17. Removal of {sup 14}C from Irradiated Graphite for Graphite Recycle and Waste Volume Reduction

    SciTech Connect (OSTI)

    Dunzik-Gougar, Mary Lou; Windes, Will; Marsden, Barry

    2014-06-10T23:59:59.000Z

    The aim of the research presented here was to identify the checmical from of {sup 14}C inirradiated graphite. A greater understanding of the chemical form of this longest-lived isotope in irradiated graphite will inform not only management of legacy waste, but also development of next generation gas-cooled reactors. Approimately 250,000 metric tons of irradiated graphite waste exists worldwide, with the largest single quantity originating in the Magnox and AGR reactors of UK. The waste quantity is expected to increase with decommissioning of Generation II reactors and deployment of Generation I gas-cooled, graphite moderated reactors. Of greatest concern for long-term disposal of irradiated graphite is carbon-14 ({sup 14}C), with a half-life of 5730 years.

  18. Calving on tidewater glaciers amplified by submarine frontal melting

    E-Print Network [OSTI]

    O'Leary, Martin

    2012-01-01T23:59:59.000Z

    While it has been shown repeatedly that ocean conditions exhibit an important control on the behaviour of grounded tidewater glaciers, modelling studies have focused largely on the effects of basal and surface melting. Here, a finite-element model of stresses near the front of a tidewater glacier is used to investigate the effects of frontal melting on calving, independently of the calving criterion used. Applications of the stress model to idealized scenarios reveal that undercutting of the ice front due to frontal melting can drive calving at up to ten times the mean melt rate. Factors which cause increased frontal melt-driven calving include a strong thermal gradient in the ice, and a concentration of frontal melt at the base of the glacier. These properties are typical of both Arctic and Antarctic tidewater glaciers. The finding that frontal melt near the base is a strong driver of calving leads to the conclusion that water temperatures near the bed of the glacier are critically important to the glacier f...

  19. Method for producing thin graphite flakes with large aspect ratios

    DOE Patents [OSTI]

    Bunnell, L. Roy (Kennewick, WA)

    1993-01-01T23:59:59.000Z

    A method for making graphite flakes of high aspect ratio by the steps of providing a strong concentrated acid and heating the graphite in the presence of the acid for a time and at a temperature effective to intercalate the acid in the graphite; heating the intercalated graphite at a rate and to a temperature effective to exfoliate the graphite in discrete layers; subjecting the graphite layers to ultrasonic energy, mechanical shear forces, or freezing in an amount effective to separate the layes into discrete flakes.

  20. Plasma arc melting of zirconium

    SciTech Connect (OSTI)

    Tubesing, P.K.; Korzekwa, D.R.; Dunn, P.S.

    1997-12-31T23:59:59.000Z

    Zirconium, like some other refractory metals, has an undesirable sensitivity to interstitials such as oxygen. Traditionally, zirconium is processed by electron beam melting to maintain minimum interstitial contamination. Electron beam melted zirconium, however, does not respond positively to mechanical processing due to its large grain size. The authors undertook a study to determine if plasma arc melting (PAM) technology could be utilized to maintain low interstitial concentrations and improve the response of zirconium to subsequent mechanical processing. The PAM process enabled them to control and maintain low interstitial levels of oxygen and carbon, produce a more favorable grain structure, and with supplementary off-gassing, improve the response to mechanical forming.

  1. Thermally efficient melting for glass making

    DOE Patents [OSTI]

    Chen, Michael S. K. (Zionsville, PA); Painter, Corning F. (Allentown, PA); Pastore, Steven P. (Allentown, PA); Roth, Gary (Trexlertown, PA); Winchester, David C. (Allentown, PA)

    1991-01-01T23:59:59.000Z

    The present invention is an integrated process for the production of glass utilizing combustion heat to melt glassmaking materials in a glassmaking furnace. The fuel combusted to produce heat sufficient to melt the glassmaking materials is combusted with oxygen-enriched oxidant to reduce heat losses from the offgas of the glassmaking furnace. The process further reduces heat losses by quenching hot offgas from the glassmaking furnace with a process stream to retain the heat recovered from quench in the glassmaking process with subsequent additional heat recovery by heat exchange of the fuel to the glassmaking furnace, as well as the glassmaking materials, such as batch and cullet. The process includes recovery of a commercially pure carbon dioxide product by separatory means from the cooled, residual offgas from the glassmaking furnace.

  2. Melting efficiency in fusion welding

    SciTech Connect (OSTI)

    Fuerschbach, P.W.

    1991-01-01T23:59:59.000Z

    Basic to our knowledge of the science of welding is an understanding of the melting efficiency, which indicates how much of the heat deposited by the welding process is used to produce melting. Recent calorimetric studies of GTAW, PAW, and LBW processes have measured the net heat input to the part thereby quantifying the energy transfer efficiency and in turn permitting an accurate determination of the melting efficiency. It is indicated that the weld process variables can dramatically affect the melting efficiency. This limiting value is shown to depend on the weld heat flow geometry as predicted by analytical solutions to the heat flow equation and as demonstrated by the recent empirical data. A new dimensionless parameter is used to predict the melting efficiency and is shown to correlate extremely well with recent empirical data. This simple prediction methodology is notable because it requires only a knowledge of the weld schedule and the material properties in order to estimate melting efficiency. 22 refs., 16 figs.

  3. Graphite oxidation modeling for application in MELCOR.

    SciTech Connect (OSTI)

    Gelbard, Fred

    2009-01-01T23:59:59.000Z

    The Arrhenius parameters for graphite oxidation in air are reviewed and compared. One-dimensional models of graphite oxidation coupled with mass transfer of oxidant are presented in dimensionless form for rectangular and spherical geometries. A single dimensionless group is shown to encapsulate the coupled phenomena, and is used to determine the effective reaction rate when mass transfer can impede the oxidation process. For integer reaction order kinetics, analytical expressions are presented for the effective reaction rate. For noninteger reaction orders, a numerical solution is developed and compared to data for oxidation of a graphite sphere in air. Very good agreement is obtained with the data without any adjustable parameters. An analytical model for surface burn-off is also presented, and results from the model are within an order of magnitude of the measurements of burn-off in air and in steam.

  4. First Direct Evidence of Dirac Fermions in Graphite

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

    in Graphite Print The recent surge of interest in the electronic properties of graphene-that is, isolated layers of graphite just one atomic layer thick-has largely been...

  5. Piezoreslstive graphite/polyimide thin films for micromachining applications

    E-Print Network [OSTI]

    Piezoreslstive graphite/polyimide thin films for micromachining applications A. Bruno Frazier) In this work, graphite/polyimide composite thin films are introduced and characterized for micromachining tetracarboxylic dianhydride+xydianiline/metaphenylene diamine polyimide matrix. The resultant material represents

  6. NOVEL SALTS OF GRAPHITE AND A BORON NITRIDE SALT

    E-Print Network [OSTI]

    Bartlett, Neil

    2011-01-01T23:59:59.000Z

    ~ i\\f'{y AND DOCUMENTS SECTION NOVEL SALTS OF GRAPHITE ANDA BORON NITRIDE SALT Neil Bartlett, R. N. Biagioni, B. W.privately owned rights. Novel Salts of Graphite and a Boron

  7. Imparting Electrical Conductivity into Asphalt Composites Using Graphite 

    E-Print Network [OSTI]

    Baranikumar, Aishwarya

    2013-07-09T23:59:59.000Z

    publications showed the potential of graphite in mitigating the sudden transition. The study presented herein investigates possibility of precisely controlling the electrical conductivity of asphalt concrete only by adding filler size graphite powder. Nine...

  8. Chemically modified graphite for electrochemical cells

    DOE Patents [OSTI]

    Greinke, R.A.; Lewis, I.C.

    1998-05-26T23:59:59.000Z

    This invention relates to chemically modified graphite particles: (a) that are useful in alkali metal-containing electrode of a electrochemical cell comprising: (1) the electrode, (2) a non-aqueous electrolytic solution comprising an organic aprotic solvent which solvent tends to decompose when the electrochemical cell is in use, and an electrically conductive salt of an alkali metal, and (3) a counter electrode; and (b) that are chemically modified with fluorine, chlorine, iodine or phosphorus to reduce such decomposition. This invention also relates to electrodes comprising such chemically modified graphite and a binder and to electrochemical cells containing such electrodes. 3 figs.

  9. Characteristics of Graphitic Films for Carbon Based Magnetism and Electronics

    E-Print Network [OSTI]

    Hong, Jeongmin

    2009-01-01T23:59:59.000Z

    the nineteenth century to exfoliate graphene, is now used tolayers of graphite to exfoliate the graphene sheets. This

  10. Effect of Vinylene Carbonate on Graphite Anode Cycling Efficiency

    E-Print Network [OSTI]

    Ridgway, Paul

    2010-01-01T23:59:59.000Z

    graphite formulations in particular, are the current standard for battery anodes in electric vehicle lithium-ion batteries (

  11. Lattice Monte Carlo Simulations of Polymer Melts

    E-Print Network [OSTI]

    Hsiao-Ping Hsu

    2015-03-03T23:59:59.000Z

    We use Monte Carlo simulations to study polymer melts consisting of fully flexible and moderately stiff chains in the bond fluctuation model at a volume fraction $0.5$. In order to reduce the local density fluctuations, we test a pre-packing process for the preparation of the initial configurations of the polymer melts, before the excluded volume interaction is switched on completely. This process leads to a significantly faster decrease of the number of overlapping monomers on the lattice. This is useful for simulating very large systems, where the statistical properties of the model with a marginally incomplete elimination of excluded volume violations are the same as those of the model with strictly excluded volume. We find that the internal mean square end-to-end distance for moderately stiff chains in a melt can be very well described by a freely rotating chain model with a precise estimate of the bond-bond orientational correlation between two successive bond vectors in equilibrium. The plot of the probability distributions of the reduced end-to-end distance of chains of different stiffness also shows that the data collapse is excellent and described very well by the Gaussian distribution for ideal chains. However, while our results confirm the systematic deviations between Gaussian statistics for the chain structure factor $S_c(q)$ [minimum in the Kratky-plot] found by Wittmer et al.~\\{EPL {\\bf 77} 56003 (2007).\\} for fully flexible chains in a melt, we show that for the available chain length these deviations are no longer visible, when the chain stiffness is included. The mean square bond length and the compressibility estimated from collective structure factors depend slightly on the stiffness of the chains.

  12. Method of making segmented pyrolytic graphite sputtering targets

    DOE Patents [OSTI]

    McKernan, M.A.; Alford, C.S.; Makowiecki, D.M.; Chen, C.W.

    1994-02-08T23:59:59.000Z

    Anisotropic pyrolytic graphite wafers are oriented and bonded together such that the graphite's high thermal conductivity planes are maximized along the back surface of the segmented pyrolytic graphite target to allow for optimum heat conduction away from the sputter target's sputtering surface and to allow for maximum energy transmission from the target's sputtering surface. 2 figures.

  13. Nanometal-Decorated Exfoliated Graphite Nanoplatelet Based Glucose

    E-Print Network [OSTI]

    Lee, Ilsoon

    Nanometal-Decorated Exfoliated Graphite Nanoplatelet Based Glucose Biosensors with High Sensitivity demonstrated for the first time that exfoli- ated graphite nanoplatelets (xGnPs), which are 1 10 nm, and affordable amperometric glucose biosensor using exfoliated graphite nanoplatelets (xGnPs) decorated with Pt

  14. Engineering of Ferrite-Graphite Composite Media for Microwave Shields

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    Engineering of Ferrite-Graphite Composite Media for Microwave Shields Marina Koledintseva, PoornaAA@mpei.ru Abstract-- An electromagnetic shielding of objects using ferrite-graphite composites is considered- shielding; dielectric base material; ferrite- graphite composite, Maxwell Garnett formulation I

  15. Glass science tutorial: Lecture No. 4, commercial glass melting and associated air emission issues

    SciTech Connect (OSTI)

    Kruger, A.A.

    1995-01-01T23:59:59.000Z

    This document serves as a manual for a workshop on commercial glass melting and associated air emission issues. Areas covered include: An overview of the glass industry; Furnace design and construction practices; Melting furnace operation; Energy input methods and controls; Air legislation and regulations; Soda lime emission mechanisms; and, Post furnace emission controls. Supporting papers are also included.

  16. US graphite reactor D&D experience

    SciTech Connect (OSTI)

    Garrett, S.M.K.; Williams, N.C.

    1997-02-01T23:59:59.000Z

    This report describes the results of the U.S. Graphite Reactor Experience Task for the Decommissioning Strategy Plan for the Leningrad Nuclear Power Plant (NPP) Unit 1 Study. The work described in this report was performed by the Pacific Northwest National Laboratory (PNNL) for the Department of Energy (DOE).

  17. Graphite formation in the Hiroshima fire storm

    SciTech Connect (OSTI)

    Fields, D.E.; Crenshaw, M.; Yalcintas, M.G.; Strehlow, R.A. (Oak Ridge National Lab., TN (USA)); Cole, L.L. (Prairie View A and M Univ., TX (USA))

    1991-01-01T23:59:59.000Z

    In order to investigate what might be the composition and optical properties of particles that could lead to a nuclear winter, a search has been made for particles that had been generated in urban fire storms. Deposits containing small amounts of graphite have been found on an artifact from the Hiroshima fire storm. The fire storm was initiated on August 6, 1945, by the atomic bomb detonation. The particles were rained out of the atmosphere in the black rain that commenced following the urban fire storm. Initial studies using electron microscopy have revealed that the particles consist of a mixture of clay and amorphous sooty carbon. Scanning electron photomicrographs have suggested the presence of graphite. Its presence has been confirmed using laser Raman spectroscopy (LRS), surface ionization mass spectroscopy (SIMS), and electron scattering for chemical analysis (ESCA). Significant amounts of the sooty material consist of clay, and the graphite is probably present as short-range ordered structure in sooty microspheres. The results of this study are presented with a discussion of conditions that may lead to graphite formation.

  18. Graphite Oxidation Simulation in HTR Accident Conditions

    SciTech Connect (OSTI)

    El-Genk, Mohamed

    2012-10-19T23:59:59.000Z

    Massive air and water ingress, following a pipe break or leak in steam-generator tubes, is a design-basis accident for high-temperature reactors (HTRs). Analysis of these accidents in both prismatic and pebble bed HTRs requires state-of-the-art capability for predictions of: 1) oxidation kinetics, 2) air ?helium gas mixture stratification and diffusion into the core following the depressurization, 3) transport of multi-species gas mixture, and 4) graphite corrosion. This project will develop a multi-dimensional, comprehensive oxidation kinetics model of graphite in HTRs, with diverse capabilities for handling different flow regimes. The chemical kinetics/multi-species transport model for graphite burning and oxidation will account for temperature-related changes in the properties of graphite, oxidants (O2, H2O, CO), reaction products (CO, CO2, H2, CH4) and other gases in the mixture (He and N2). The model will treat the oxidation and corrosion of graphite in geometries representative of HTR core component at temperatures of 900°C or higher. The developed chemical reaction kinetics model will be user-friendly for coupling to full core analysis codes such as MELCOR and RELAP, as well as computational fluid dynamics (CFD) codes such as CD-adapco. The research team will solve governing equations for the multi-dimensional flow and the chemical reactions and kinetics using Simulink, an extension of the MATLAB solver, and will validate and benchmark the model's predictions using reported experimental data. Researchers will develop an interface to couple the validated model to a commercially available CFD fluid flow and thermal-hydraulic model of the reactor , and will perform a simulation of a pipe break in a prismatic core HTR, with the potential for future application to a pebble-bed type HTR.

  19. Conversion of lignin precursors to carbon fibers with nanoscale graphitic domains

    SciTech Connect (OSTI)

    Chatterjee, Sabornie [ORNL; Jones, Eric B [ORNL; Clingenpeel, Amy [National High Magnetic Field Laboratory (Magnet Lab), Florida; McKenna, Amy [National High Magnetic Field Laboratory (Magnet Lab), Florida; Rios, Orlando [ORNL; McNutt, Nicholas W [ORNL; Keffer, David J. [University of Tennessee, Knoxville (UTK); Johs, Alexander [ORNL

    2014-01-01T23:59:59.000Z

    Lignin is one of the most abundant and inexpensive natural biopolymers. It can be efficiently converted to low cost carbon fiber, monolithic structures or powders that could be used directly in the production of anodes for lithium-ion batteries. In this work, we report processing parameters relevant for the conversion of lignin precursors into electrochemically active carbon fibers, the impact of lignin precursor modification on melt processing and the microstructure of the final carbon material. The conversion process encompasses melt spinning of the lignin precursor, oxidative stabilization and a low temperature carbonization step in a nitrogen/hydrogen atmosphere. To assess electrochemical performance, we determined resistivities of individual carbon fiber samples and characterized the microstructure by scanning electron microscopy and neutron diffraction. The chemical modification and subsequent thermomechanical processing methods reported here are effective for conversion into carbon fibers while preserving the macromolecular backbone structure of lignin. Modification of softwood lignin produced functionalities and rheological properties that more closely resemble hardwood lignin thereby enabling the melt processing of softwood lignin in oxidative atmospheres (air). Structural characterization of the carbonized fibers reveals nanoscale graphitic domains that are linked to enhanced electrochemical performance.

  20. Status of the NGNP graphite creep experiments AGC-1 and AGC-2 irradiated in the advanced test reactor

    SciTech Connect (OSTI)

    S. Blaine Grover

    2014-05-01T23:59:59.000Z

    The United States Department of Energy's Next Generation Nuclear Plant (NGNP) Program will be irradiating six nuclear graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the next generation nuclear plant (NGNP) very high temperature gas reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six peripheral stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six peripheral stacks will have three different compressive loads applied to the top half of three diametrically opposite pairs of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during irradiation of the experiment.

  1. Dry melting of high albite

    SciTech Connect (OSTI)

    Anovitz, L.M.: Blencoe, J.G.

    1999-12-01T23:59:59.000Z

    The properties of albitic melts are central to thermodynamic models for synthetic and natural granitic liquids. The authors have analyzed published phase-equilibrium and thermodynamic data for the dry fusion of high albite to develop a more accurate equation for the Biggs free energy of this reaction to 30 kbar and 1,400 C. Strict criteria for reaction reversal were sued to evaluate the phase-equilibrium data, and the thermodynamic properties of solid and liquid albite were evaluated using the published uncertainties in the original measurements. Results suggest that neither available phase-equilibrium experiments nor thermodynamic data tightly constrain the location of the reaction. Experimental solidus temperatures at 1 atm range from 1,100 to 1,120 C. High-pressure experiments were not reversed completely and may have been affected by several sources of error, but the apparent inconsistencies among the results of the various experimentalists are eliminated when only half-reversal data are considered. Uncertainties in thermodynamic data yield large variations in permissible reaction slopes. Disparities between experimental and calculated melting curves are, therefore, largely attributable to these difficulties, and there is no fundamental disagreement between the available phase-equilibrium and thermodynamic data for the dry melting of albite. Consequently, complex speciation models for albitic melts, based on the assumption that these discrepancies represent a real characteristic of the system, are unjustified at this time.

  2. Stability and breakdown of Ca{sup 13}CO{sub 3} melt associated with formation of {sup 13}C-diamond in static high pressure experiments up to 43 GPa and 3900 K

    SciTech Connect (OSTI)

    Spivak, A.V., E-mail: spivak@iem.ac.ru [Institute of Experimental Mineralogy of the Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation); Litvin, Yu.A. [Institute of Experimental Mineralogy of the Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation); Ovsyannikov, S.V. [Bayerishes Geoinstitut, University of Bayreuth, Bayreuth (Germany); Dubrovinskaia, N.A. [Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, Bayreuth (Germany); Dubrovinsky, L.S. [Bayerishes Geoinstitut, University of Bayreuth, Bayreuth (Germany)

    2012-07-15T23:59:59.000Z

    Melting of calcium carbonate Ca{sup 13}CO{sub 3}, stability of the melt and its decomposition were studied in static high pressure experiments at pressures of 11-43 GPa and temperatures of 1600-3900 K using diamond anvil cell technique with laser heating. We observed formation of {sup 13}C-graphite (below 16 GPa) and {sup 13}C-diamond (between 16 and 43 GPa) on decomposition of the Ca{sup 13}CO{sub 3} melt at temperatures above 3400 K. At temperatures below 3400 K congruent melting of calcium carbonate was confirmed. The experimental results were applied to construction of the phase diagram of CaCO{sub 3} up to 43 GPa and 3900 K focusing at the melting curve of calcium carbonate and the decomposition phase boundary of CaCO{sub 3} melt. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer Phase states of CaCO{sub 3} were studied at P=11-43 GPa and T=1600-3900 K. Black-Right-Pointing-Pointer {sup 13}C-diamond easily crystallizes in carbonate-carbon (Ca{sup 13}CO{sub 3-}{sup 13}C-graphite) melt-solutions. Black-Right-Pointing-Pointer Ca-carbonate melts congruently that was observed in experiments in DAC with laser heating. Black-Right-Pointing-Pointer Decomposition of CaCO{sub 3} melt, indicated by formation of graphite and/or diamond. Black-Right-Pointing-Pointer Decomposition of CaCO{sub 3} was observed at temperatures above 3400 K in the pressure interval studied.

  3. The core structure of presolar graphite onions

    E-Print Network [OSTI]

    P. Fraundorf; Martin Wackenhut

    2001-10-28T23:59:59.000Z

    Of the ``presolar particles'' extracted from carbonaceous chondrite dissolution residues, i.e. of those particles which show isotopic evidence of solidification in the neighborhood of other stars prior to the origin of our solar system, one subset has an interesting concentric graphite-rim/graphene-core structure. We show here that single graphene sheet defects in the onion cores (e.g. cyclopentane loops) may be observable edge-on by HREM. This could allow a closer look at models for their formation, and in particular strengthen the possibility that growth of these assemblages proceeds atom-by-atom with the aid of such in-plane defects, under conditions of growth (e.g. radiation fluxes or grain temperature) which discourage the graphite layering that dominates subsequent formation of the rim.

  4. Atomic resolution images of graphite in air

    SciTech Connect (OSTI)

    Grigg, D.A.; Shedd, G.M.; Griffis, D.; Russell, P.E.

    1988-12-01T23:59:59.000Z

    One sample used for proof of operation for atomic resolution in STM is highly oriented pyrolytic graphite (HOPG). This sample has been imaged with many different STM`s obtaining similar results. Atomic resolution images of HOPG have now been obtained using an STM designed and built at the Precision Engineering Center. This paper discusses the theoretical predictions and experimental results obtained in imaging of HOPG.

  5. Nondestructive Evaluation of Nuclear-Grade Graphite

    SciTech Connect (OSTI)

    Dennis C. Kunerth; Timothy R. McJunkin

    2011-07-01T23:59:59.000Z

    Nondestructive Evaluation of Nuclear Grade Graphite Dennis C. Kunerth and Timothy R. McJunkin Idaho National Laboratory Idaho Falls, ID, 83415 This paper discusses the nondestructive evaluation of nuclear grade graphite performed at the Idaho National Laboratory. Graphite is a composite material highly dependent on the base material and manufacturing methods. As a result, material variations are expected within individual billets as well billet to billet and lot to lot. Several methods of evaluating the material have been explored. Particular technologies each provide a subset of information about the material. This paper focuses on techniques that are applicable to in-service inspection of nuclear energy plant components. Eddy current examination of the available surfaces provides information on potential near surface structural defects and although limited, ultrasonics can be utilized in conventional volumetric inspection. Material condition (e.g. micro-cracking and porosity induced by radiation and stress) can be derived from backscatter or acousto-ultrasound (AU) methods. Novel approaches utilizing phased array ultrasonics have been attempted to expand the abilities of AU techniques. By combining variable placement of apertures, angle and depth of focus, the techniques provide the potential to obtain parameters at various depths in the material. Initial results of the study and possible procedures for application of the techniques are discussed.

  6. Vapor deposition of water on graphitic surfaces: Formation of amorphous ice, bilayer ice, ice I, and liquid water

    SciTech Connect (OSTI)

    Lupi, Laura; Kastelowitz, Noah; Molinero, Valeria, E-mail: Valeria.Molinero@utah.edu [Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850 (United States)

    2014-11-14T23:59:59.000Z

    Carbonaceous surfaces are a major source of atmospheric particles and could play an important role in the formation of ice. Here we investigate through molecular simulations the stability, metastability, and molecular pathways of deposition of amorphous ice, bilayer ice, and ice I from water vapor on graphitic and atomless Lennard-Jones surfaces as a function of temperature. We find that bilayer ice is the most stable ice polymorph for small cluster sizes, nevertheless it can grow metastable well above its region of thermodynamic stability. In agreement with experiments, the simulations predict that on increasing temperature the outcome of water deposition is amorphous ice, bilayer ice, ice I, and liquid water. The deposition nucleation of bilayer ice and ice I is preceded by the formation of small liquid clusters, which have two wetting states: bilayer pancake-like (wetting) at small cluster size and droplet-like (non-wetting) at larger cluster size. The wetting state of liquid clusters determines which ice polymorph is nucleated: bilayer ice nucleates from wetting bilayer liquid clusters and ice I from non-wetting liquid clusters. The maximum temperature for nucleation of bilayer ice on flat surfaces, T{sub B}{sup max} is given by the maximum temperature for which liquid water clusters reach the equilibrium melting line of bilayer ice as wetting bilayer clusters. Increasing water-surface attraction stabilizes the pancake-like wetting state of liquid clusters leading to larger T{sub B}{sup max} for the flat non-hydrogen bonding surfaces of this study. The findings of this study should be of relevance for the understanding of ice formation by deposition mode on carbonaceous atmospheric particles, including soot.

  7. Flexible graphite modified by carbon black paste for use as a thermal interface material

    E-Print Network [OSTI]

    Chung, Deborah D.L.

    graphite is a material that is made by the com- pression of exfoliated graphite, which is in turn made by the exfoliation of intercalated graphite flake [3]. Due to the accordion-like microstructure of exfoliated graphite, mechan- ical interlocking between pieces of exfoliated graphite (each piece obtained from a flake

  8. Technical and economical considerations of new DRI melting process

    SciTech Connect (OSTI)

    Ito, Shuzo; Tokuda, Koji; Sammt, F.; Gray, R.

    1997-12-31T23:59:59.000Z

    The new DRI melting process can effectively and economically produce high quality molten iron. This process utilizes hot charging of DRI directly from a reduction furnace into a dedicated new melting furnace. The molten iron from this DRI premelter can be charged into a steelmaking furnace, such as an electric arc furnace (EAF), where the molten iron, together with other iron sources, can be processed to produce steel. Alternatively the molten iron can be pigged or granulated for off-site merchant sales. Comprehensive research and development of the new process has been conducted including operational process simulation, melting tests using FASTMET DRI, slag technology development, and refractory corrosion testing. This paper describes the process concept, its operational characteristics and further applications of the process.

  9. Resonating Valence Bonds and Mean-Field d-Wave Superconductivity in Graphite

    SciTech Connect (OSTI)

    Black-Schaffer, Annica M.

    2010-04-27T23:59:59.000Z

    We investigate the possibility of inducing superconductivity in a graphite layer by electronic correlation effects. We use a phenomenological microscopic Hamiltonian which includes nearest neighbor hopping and an interaction term which explicitly favors nearest neighbor spin-singlets through the well-known resonance valence bond (RVB) character of planar organic molecules. Treating this Hamiltonian in mean-field theory, allowing for bond-dependent variation of the RVB order parameter, we show that both s- and d-wave superconducting states are possible. The d-wave solution belongs to a two-dimensional representation and breaks time reversal symmetry. At zero doping there exists a quantum critical point at the dimensionless coupling J/t = 1.91 and the s- and d-wave solutions are degenerate for low temperatures. At finite doping the d-wave solution has a significantly higher T{sub c} than the s-wave solution. By using density functional theory we show that the doping induced from sulfur absorption on a graphite layer is enough to cause an electronically driven d-wave superconductivity at graphite-sulfur interfaces. We also discuss applying our results to the case of the intercalated graphites as well as the validity of a mean-field approach.

  10. Advanced Surface and Microstructural Characterization of Natural Graphite Anodes for Lithium Ion Batteries

    SciTech Connect (OSTI)

    Gallego, Nidia C [ORNL] [ORNL; Contescu, Cristian I [ORNL] [ORNL; Meyer III, Harry M [ORNL] [ORNL; Howe, Jane Y [ORNL] [ORNL; Meisner, Roberta Ann [ORNL] [ORNL; Payzant, E Andrew [ORNL] [ORNL; Lance, Michael J [ORNL] [ORNL; Yoon, Steve [A123 Systems, Inc.] [A123 Systems, Inc.; Denlinger, Matthew [A123 Systems, Inc.] [A123 Systems, Inc.; Wood III, David L [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Natural graphite powders were subjected to a series of thermal treatments in order to improve the anode irreversible capacity loss (ICL) and capacity retention during long-term cycling of lithium ion batteries. A baseline thermal treatment in inert Ar or N2 atmosphere was compared to cases with a proprietary additive to the furnace gas environment. This additive substantially altered the surface chemistry of the natural graphite powders and resulted in significantly improved long-term cycling performance of the lithium ion batteries over the commercial natural graphite baseline. Different heat-treatment temperatures were investigated ranging from 950-2900 C with the intent of achieving the desired long-term cycling performance with as low of a maximum temperature and thermal budget as possible. A detailed summary of the characterization data is also presented, which includes X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and temperature-programed desorption mass spectroscopy (TPD-MS). This characterization data was correlated to the observed capacity fade improvements over the course of long-term cycling at high charge-discharge rates in full lithium-ion coin cells. It is believed that the long-term performance improvements are a result of forming a more stable solid electrolyte interface (SEI) layer on the anode graphite surfaces, which is directly related to the surface chemistry modifications imparted by the proprietary gas environment during thermal treatment.

  11. Nucleation and growth in electrodeposition of thin copper films on pyrolytic graphite

    SciTech Connect (OSTI)

    Kinaci, F.S.; Muller, R.H.

    1992-05-01T23:59:59.000Z

    Electrodeposition of Cu on graphite electrodes was studied, with emphasis on nucleation. Various ex-situ and in-situ methods were investigated for determining the number density of nuclei. Two direct methods were studied (scanning electron microscopy and scanning tunneling microscopy); indirect determinations included Raman spectroscopy and analysis of potentiostatic current transients. Though some of the techniques correctly predicted the nucleation densities under special conditions, SEM was the most reliable tool. The large scatter in the data necessitated steps to minimize this effect. To electrodeposit Cu on graphite, a nucleation overpotential of 250 mV was measured with cyclic voltammetry; such a large overpotential does not occur on a Pt or on a Cu-covered graphite electrode. The deposition potential is the dominant parameter governing nucleation density. There is a sharp increase in the nucleation density with applied potential. Cu can be deposited on highly oriented pyrolytic graphite only between the nucleation overpotential and the hydrogen evolution potential. To increase the Cu nucleation density, while avoiding excessive H evolution, a double pulse potential technique was used; nucleation densities on the order of 10{sup 10} nuclei/cm{sup 2} were achieved. The use of inhibitors (PVA, benzotriazole) was also investigated. Deposition on conducting polymer electrodes was also studied; initial results with polyaniline show promise. 57 figs, 6 tabs, refs. (DLC)

  12. Direct printing and reduction of graphite oxide for flexible supercapacitors

    SciTech Connect (OSTI)

    Jung, Hanyung [Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul (Korea, Republic of); Ve Cheah, Chang [Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Jeong, Namjo [Energy Materials and Convergence Research Department, Korea Institute of Energy Research, Daejeon (Korea, Republic of); Lee, Junghoon, E-mail: jleenano@snu.ac.kr [Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul (Korea, Republic of); Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of)

    2014-08-04T23:59:59.000Z

    We report direct printing and photo-thermal reduction of graphite oxide (GO) to obtain a highly porous pattern of interdigitated electrodes, leading to a supercapacitor on a flexible substrate. Key parameters optimized include the amount of GO delivered, the suitable photo-thermal energy level for effective flash reduction, and the substrate properties for appropriate adhesion after reduction. Tests with supercapacitors based on the printed-reduced GO showed performance comparable with commercial supercapacitors: the energy densities were 1.06 and 0.87 mWh/cm{sup 3} in ionic and organic electrolytes, respectively. The versatility in the architecture and choice of substrate makes this material promising for smart power applications.

  13. austempered spheroidal graphite: Topics by E-print Network

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

    Office of Environmental Management U.S. Department of Energy BNL): - Remove the graphite pile - Construct an engineered cap - Remove the bioshield Environmental...

  14. Putting the Spin on Graphite: Observing the Spins of Impurity...

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

    the Spins of Impurity Atoms Align Friday, February 28, 2014 The existence of magnetism in graphite is a very intriguing subject. The possibility to exploit the magnetic...

  15. Role of Nuclear Grade Graphite in Oxidation in Modular HTGRs

    SciTech Connect (OSTI)

    Willaim Windes; G. Strydom; J. Kane; R. Smith

    2014-11-01T23:59:59.000Z

    The passively safe High Temperature Gas-cooled Reactor (HTGR) design is one of the primary concepts considered for Generation IV and Small Modular Reactor (SMR) programs. The helium cooled, nuclear grade graphite moderated core achieves extremely high operating temperatures allowing either industrial process heat or electricity generation at high efficiencies. In addition to their neutron moderating properties, nuclear grade graphite core components provide excellent high temperature stability, thermal conductivity, and chemical compatibility with the high temperature nuclear fuel form. Graphite has been continuously used in nuclear reactors since the 1940’s and has performed remarkably well over a wide range of core environments and operating conditions. Graphite moderated, gas-cooled reactor designs have been safely used for research and power production purposes in multiple countries since the inception of nuclear energy development. However, graphite is a carbonaceous material, and this has generated a persistent concern that the graphite components could actually burn during either normal or accident conditions [ , ]. The common assumption is that graphite, since it is ostensibly similar to charcoal and coal, will burn in a similar manner. While charcoal and coal may have the appearance of graphite, the internal microstructure and impurities within these carbonaceous materials are very different. Volatile species and trapped moisture provide a source of oxygen within coal and charcoal allowing them to burn. The fabrication process used to produce nuclear grade graphite eliminates these oxidation enhancing impurities, creating a dense, highly ordered form of carbon possessing high thermal diffusivity and strongly (covalently) bonded atoms.

  16. Chemistry modification of high oxygen-carbon powder by plasma melting: Follow up to complete the story

    SciTech Connect (OSTI)

    Dunn, P.S.; Korzekwa, D.R.; Garcia, F.G. [Los Alamos National Lab., NM (United States); Michaluk, C.A. [Cabot Performance Materials (United States)

    1998-03-01T23:59:59.000Z

    State of the art melting of tantalum and tantalum alloys has relied on electron beam (EB) or vacuum arc remelting (VAR) for commercial ingot production. Plasma arc melting (PAM) provides an alternative for melting tantalum that contains very high levels of interstitials where other melting techniques can not be applied. Previous work in this area centered on plasma arc melt quality and final interstitial content of tantalum feedstock containing excessive levels of interstitial impurities as a function of melt rate and plasma gas. This report is an expansion of this prior study and provides the findings from the analysis of second phase components observed in the microstructure of the PAM tantalum. In addition, results from subsequent EB melting trials of PAM tantalum are included.

  17. Letter to the Editor Microwave assisted exfoliation and reduction of graphite

    E-Print Network [OSTI]

    Letter to the Editor Microwave assisted exfoliation and reduction of graphite oxide yet versatile method to simultaneously achieve the exfoliation and reduction of graphite oxide of crumpled, few-layer thick and electronically conductive graphitic sheets. Using the microwave exfoliated

  18. Low-cost and durable catalyst support for fuel cells: graphite...

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

    cost and durable catalyst support for fuel cells: graphite submicronparticles. Low-cost and durable catalyst support for fuel cells: graphite submicronparticles. Abstract: Low-cost...

  19. Safety aspects of EB melting

    SciTech Connect (OSTI)

    Hainz, L.C. [Hainz Engineering Services, Inc., Albany, OR (United States)

    1994-12-31T23:59:59.000Z

    Electron Beam melting technology, along with other vacuum metallurgical technologies, requires special attention to safety involving operation and maintenance of the EB furnace and systems. Although the EB industry has been relatively accident free, the importance of safety awareness and compliance becomes increasingly important. It is very important to provide a safe work environment for employees and economically important to protect the equipment from damage and potential downtime. Safety and accident prevention directly affects overhead costs by keeping accident insurance rates at a minimum. Routine safety requirements will be reviewed and safety aspects requiring extra attention will be addressed. Safety improvements and experiences of furnace users will be shared as examples.

  20. On the formation of continental silicic melts in thermo-chemical

    E-Print Network [OSTI]

    van Thienen, Peter

    Chapter 7 On the formation of continental silicic melts in thermo-chemical mantle convection models-consistently produced by numerical thermo- chemical mantle convection models, presented in this paper, including partial

  1. Multiscale modeling of polyisoprene on graphite

    SciTech Connect (OSTI)

    Pandey, Yogendra Narayan; Brayton, Alexander; Doxastakis, Manolis, E-mail: edoxastakis@uh.edu [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States)] [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States); Burkhart, Craig; Papakonstantopoulos, George J. [Global Materials Science Division, The Goodyear Tire and Rubber Company, Akron, Ohio 44305 (United States)] [Global Materials Science Division, The Goodyear Tire and Rubber Company, Akron, Ohio 44305 (United States)

    2014-02-07T23:59:59.000Z

    The local dynamics and the conformational properties of polyisoprene next to a smooth graphite surface constructed by graphene layers are studied by a multiscale methodology. First, fully atomistic molecular dynamics simulations of oligomers next to the surface are performed. Subsequently, Monte Carlo simulations of a systematically derived coarse-grained model generate numerous uncorrelated structures for polymer systems. A new reverse backmapping strategy is presented that reintroduces atomistic detail. Finally, multiple extensive fully atomistic simulations with large systems of long macromolecules are employed to examine local dynamics in proximity to graphite. Polyisoprene repeat units arrange close to a parallel configuration with chains exhibiting a distribution of contact lengths. Efficient Monte Carlo algorithms with the coarse-grain model are capable of sampling these distributions for any molecular weight in quantitative agreement with predictions from atomistic models. Furthermore, molecular dynamics simulations with well-equilibrated systems at all length-scales support an increased dynamic heterogeneity that is emerging from both intermolecular interactions with the flat surface and intramolecular cooperativity. This study provides a detailed comprehensive picture of polyisoprene on a flat surface and consists of an effort to characterize such systems in atomistic detail.

  2. Low melting high lithia glass compositions and methods

    DOE Patents [OSTI]

    Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

    2003-09-23T23:59:59.000Z

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste uranium oxides The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  3. Carbon Characterization Laboratory Readiness to Receive Irradiated Graphite Samples

    SciTech Connect (OSTI)

    Karen A. Moore

    2011-05-01T23:59:59.000Z

    The Carbon Characterization Laboratory (CCL) is located in Labs C19 and C20 of the Idaho National Laboratory Research Center. The CCL was established under the Next Generation Nuclear Plant Project to support graphite and ceramic composite research and development activities. The research conducted in this laboratory will support the Advanced Graphite Creep experiments—a major series of material irradiation experiments within the Next Generation Nuclear Plant Graphite program. The CCL is designed to characterize and test low activated irradiated materials such as high purity graphite, carbon-carbon composites, silicon-carbide composite, and ceramic materials. The laboratory is fully capable of characterizing material properties for both irradiated and nonirradiated materials. Major infrastructural modifications were undertaken to support this new radiological facility at Idaho National Laboratory. Facility modifications are complete, equipment has been installed, radiological controls and operating procedures have been established and work management documents have been created to place the CCL in readiness to receive irradiated graphite samples.

  4. EPAC02_graphite.doc STUDY OF GRAPHITE TARGETS INTERACTING WITH THE 24 GeV PROTON

    E-Print Network [OSTI]

    McDonald, Kirk

    materials selected for the experiment are ATJ graphite and the anisotropic carbon-carbon composite. Each, in the first phase of the E951 experiment, graphite and carbon-carbon composite targets were exposed to the AGS to evaluate candidate target materials for the future muon collider/neutrino factory carbon-based solid

  5. Geothermal: Sponsored by OSTI -- Pavement Snow Melting

    Office of Scientific and Technical Information (OSTI)

    Pavement Snow Melting Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us HomeBasic Search About Publications Advanced Search New Hot Docs News Related...

  6. Plasma Sprayed Pour Tubes and Other Melt Handling Components for Use in Gas Atomization

    SciTech Connect (OSTI)

    Byrd, David; Rieken, Joel; Heidloff, Andy; Besser, Matthew; Anderson, Iver

    2011-04-01T23:59:59.000Z

    Ames Laboratory has successfully used plasma sprayed ceramic components made from yttria stabilized zirconia as melt pouring tubes for gas atomization for many years. These tubes have proven to be strong, thermal shock resistant and versatile. Various configurations are possible both internally and externally. Accurate dimensions are achieved internally with a machined fugitive graphite mandrel and externally by diamond grinding. The previous study of the effect of spray parameters on density was extended to determine the effect of the resulting density on the thermal shock characteristics on down-quenching and up-quenching. Encouraging results also prompted investigation of the use of plasma spraying as a method to construct a melt pour exit stopper that is mechanically robust, thermal shock resistant, and not susceptible to attack by reactive melt additions. The Ames Laboratory operates two close-coupled high pressure gas atomizers. These two atomizers are designed to produce fine and coarse spherical metal powders (5{mu} to 500{mu} diameter) of many different metals and alloys. The systems vary in size, but generally the smaller atomizer can produce up to 5 kg of powder whereas the larger can produce up to 25 kg depending on the charge form and density. In order to make powders of such varying compositions, it is necessary to have melt systems capable of heating and containing the liquid charge to the desired superheat temperature prior to pouring through the atomization nozzle. For some metals and alloys this is not a problem; however for some more reactive and/or high melting materials this can pose unique challenges. Figure 1 is a schematic that illustrates the atomization system and its components.

  7. Volatilization of Fission Products from Metallic Melts in the Melt-Dilute Treatment Technology Development for Al-Based DOE Spent Nuclear Fuels

    SciTech Connect (OSTI)

    Adams, T.

    1999-11-18T23:59:59.000Z

    The melt-dilute treatment technology is being developed to facilitate the ultimate disposition of highly enriched Al-Base DOE spent nuclear fuels in a geologic repository such as that proposed for Yucca Mountain. Currently, approximately 28 MTHM is expected to be returned to the Savannah River Site from domestic and foreign research reactors. The melt-dilute treatment technology will melt the fuel assemblies to reduce their volume and alloys them with depleted uranium to isotopically dilute the 235U concentration. The resulting alloy is cast into a form for long term geologic repository storage. Benefits accrued from the melt-dilute process include the potential for significant volume reduction; reduced criticality potential, and proliferation concerns. A critical technology element in the development of the melt-dilute process is the development of offgas system requirements. The volatilization of radioactive species during the melting stage of the process primarily constitutes the offgas in this process. Several of the species present following irradiation of a fuel assembly have been shown to be volatile or semi-volatile under reactor core melt-down conditions. Some of the key species that have previously been studied are krypton, iodine, and cesium. All of these species have been shown to volatilize during melting experiments however, the degree to which they are released is highly dependent upon atmosphere, fuel burnup, temperature, and fuel composition. With this in mind an analytical and experimental program has been undertaken to assess the volatility and capture of species under the melt-dilute operating conditions.

  8. Safety evaluation for packaging (onsite) plutonium recycle test reactor graphite cask

    SciTech Connect (OSTI)

    Romano, T.

    1997-09-29T23:59:59.000Z

    This safety evaluation for packaging (SEP) provides the evaluation necessary to demonstrate that the Plutonium Recycle Test Reactor (PRTR) Graphite Cask meets the requirements of WHC-CM-2-14, Hazardous Material Packaging and Shipping, for transfer of Type B, fissile, non-highway route controlled quantities of radioactive material within the 300 Area of the Hanford Site. The scope of this SEP includes risk, shieldling, criticality, and.tiedown analyses to demonstrate that onsite transportation safety requirements are satisfied. This SEP also establishes operational and maintenance guidelines to ensure that transport of the PRTR Graphite Cask is performed safely in accordance with WHC-CM-2-14. This SEP is valid until October 1, 1999. After this date, an update or upgrade to this document is required.

  9. Reduced Energy Consumption for Melting in Foundries

    E-Print Network [OSTI]

    ­ 336 ­ 007 TM 06 ­ 07 Department of Manufacturing Engineering and Management Technical University at the Technical University of Denmark, DTU. The project has been financed by the Danish transmission system-melted, and hence reduce the energy consumption for melting in foundries. Traditional gating systems are known

  10. Purification of tantalum by plasma arc melting

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Korzekwa, Deniece R. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    Purification of tantalum by plasma arc melting. The level of oxygen and carbon impurities in tantalum was reduced by plasma arc melting the tantalum using a flowing plasma gas generated from a gas mixture of helium and hydrogen. The flowing plasma gases of the present invention were found to be superior to other known flowing plasma gases used for this purpose.

  11. The Melting of Greenland William H. Lipscomb

    E-Print Network [OSTI]

    Born, Andreas

    ). AnAn ice capice cap is a mass of glacier ice smaller than 50,000 kmis a mass of glacier ice smaller is negligibleSurface melting is negligible Antarctic ice thicknessAntarctic ice thickness (British Antarctic of the Greenland iceMuch of the Greenland ice sheet may have meltedsheet may have melted Greenland minimum extent

  12. DOI: 10.1002/adma.200702672 Intact Pattern Transfer of Conductive Exfoliated Graphite

    E-Print Network [OSTI]

    Lee, Ilsoon

    DOI: 10.1002/adma.200702672 Intact Pattern Transfer of Conductive Exfoliated Graphite Nanoplatelet as biosensors[8,9] or in drug deliv- ery.[10,11] Exfoliated graphite has been incorporated into PEM and other incorporated into PEM.[15­18] Oxidized graphite is created by the acid treatment of graphite, which exfoliates

  13. Elastomeric behavior of exfoliated graphite, as shown by instrumented indentation testing

    E-Print Network [OSTI]

    Chung, Deborah D.L.

    Elastomeric behavior of exfoliated graphite, as shown by instrumented indentation testing Po for the first time the elastomeric behavior of a non-polymeric material, as observed in exfoliated graphite sliding of the graphite layers within the cell wall of exfoliated graphite. The reversibility is probably

  14. The contribution of glacier melt to streamflow

    SciTech Connect (OSTI)

    Schaner, Neil; Voisin, Nathalie; Nijssen, Bart; Lettenmaier, D. P.

    2012-09-13T23:59:59.000Z

    Ongoing and projected future changes in glacier extent and water storage globally have lead to concerns about the implications for water supplies. However, the current magnitude of glacier contributions to river runoff is not well known, nor is the population at risk to future glacier changes. We estimate an upper bound on glacier melt contribution to seasonal streamflow by computing the energy balance of glaciers globally. Melt water quantities are computed as a fraction of total streamflow simulated using a hydrology model and the melt fraction is tracked down the stream network. In general, our estimates of the glacier melt contribution to streamflow are lower than previously published values. Nonetheless, we find that globally an estimated 225 (36) million people live in river basins where maximum seasonal glacier melt contributes at least 10% (25%) of streamflow, mostly in the High Asia region.

  15. Nanotexturing of surfaces to reduce melting point.

    SciTech Connect (OSTI)

    Garcia, Ernest J.; Zubia, David (University of Texas at El Paso El Paso, TX); Mireles, Jose (Universidad Aut%C3%94onoma de Ciudad Ju%C3%94arez Ciudad Ju%C3%94arez, Mexico); Marquez, Noel (University of Texas at El Paso El Paso, TX); Quinones, Stella (University of Texas at El Paso El Paso, TX)

    2011-11-01T23:59:59.000Z

    This investigation examined the use of nano-patterned structures on Silicon-on-Insulator (SOI) material to reduce the bulk material melting point (1414 C). It has been found that sharp-tipped and other similar structures have a propensity to move to the lower energy states of spherical structures and as a result exhibit lower melting points than the bulk material. Such a reduction of the melting point would offer a number of interesting opportunities for bonding in microsystems packaging applications. Nano patterning process capabilities were developed to create the required structures for the investigation. One of the technical challenges of the project was understanding and creating the specialized conditions required to observe the melting and reshaping phenomena. Through systematic experimentation and review of the literature these conditions were determined and used to conduct phase change experiments. Melting temperatures as low as 1030 C were observed.

  16. Mechanism of sulfate segregation during glass melting

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Vienna, John D.; Ricklefs, Joel S.

    2005-02-13T23:59:59.000Z

    Sulfate retention in glass during the vitrification process can be as low as 1/3 of the solubility limit, or can exceed the solubility limit if suspended in the glass in the form of droplets. This study is focused on the mechanism of incorporating and segregating sodium sulfate during the melting of an alkali-alumino-borosilicate glass batch. Batches were ramp heated at 4°C/min to temperatures ranging from 600°C to 1050°C and fractured for examination. Observation of the melts showed that as the batch temperature increases and the primary oxo-anionic, predominantly nitrate melt decomposes, the sulfate residue accumulates inside gas bubbles and is transported in them to the melt surface, where it remains segregated. The degree of sulfate incorporation into the final glass depends on the relative rates of sulfate dissolution in the borosilicate melt and sulfate lifting inside bubbles.

  17. Internship Contract (Includes Practicum)

    E-Print Network [OSTI]

    Thaxton, Christopher S.

    Internship Contract (Includes Practicum) Student's name-mail: _________________________________________ Internship Agency Contact Agency Name: ____________________________________ Address-mail: __________________________________________ Location of Internship, if different from Agency: ________________________________________________ Copies

  18. Status of the NGNP Graphite Creep Experiments AGC-1 and AGC-2 Irradiated in the Advanced Test Reactor

    SciTech Connect (OSTI)

    Blaine Grover

    2012-10-01T23:59:59.000Z

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six nuclear graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant (NGNP) Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six peripheral stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six peripheral stacks will have different compressive loads applied to the top half of each pair of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during irradiation of the experiment. The first experiment, AGC-1, started its irradiation in September 2009, and the irradiation was completed in January 2011. The second experiment, AGC-2, started its irradiation in April 2011 and completed its irradiation in May 2012. This paper will briefly discuss the design of the experiment and control systems, and then present the irradiation results for each experiment to date.

  19. Pump apparatus including deconsolidator

    DOE Patents [OSTI]

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07T23:59:59.000Z

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  20. First Direct Evidence of Dirac Fermions in Graphite

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

    27 June 2007 00:00 The recent surge of interest in the electronic properties of graphene-that is, isolated layers of graphite just one atomic layer thick-has largely been...

  1. Mechanics of fatigue damage in titanium-graphite hybrid laminates

    E-Print Network [OSTI]

    Burianek, Dennis Arthur

    2001-01-01T23:59:59.000Z

    Titanium-graphite hybrid laminates are being developed for high-temperature aerospace applications. Experimental observations have indicated that cracks in the titanium facesheets initiate at free edges as well as in areas ...

  2. TRACES Centre Thermo GFS35 Graphite Furnace Spectrometer

    E-Print Network [OSTI]

    Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

    TRACES Centre Thermo GFS35 Graphite Furnace Spectrometer Standard Operating Procedure 1. Turn. Click on the lamp icon a. ID the lamp of choice and click the `Off' button to `On' b. Non-Thermo lamps

  3. BGRR-039, Rev. 0 Brookhaven Graphite Research Reactor

    E-Print Network [OSTI]

    ........................................................................................................ 17 4.0 Waste Management 17 5.0 Lessons Learned 18 6.0 REFERENCES 19 Appendix A Action MemorandumBGRR-039, Rev. 0 Brookhaven Graphite Research Reactor Decommissioning Project FINAL COMPLETION

  4. Direct exfoliation of natural graphite into micrometer size few...

    Office of Scientific and Technical Information (OSTI)

    Direct exfoliation of natural graphite into micrometer size few layers graphene sheets using ionic liquids Re-direct Destination: Stable high-concentration suspensions (up to 0.95...

  5. Dry synthesis of lithium intercalated graphite powders and carbon fibers

    SciTech Connect (OSTI)

    Sacci, Robert L [ORNL; Adamczyk, Leslie A [ORNL; Veith, Gabriel M [ORNL; Dudney, Nancy J [ORNL

    2014-01-01T23:59:59.000Z

    Herein we describe the direct synthesis of lithium intercalated graphite by heating under vacuum or ball milling under pressurized Ar(g). Both methods allow for stoichometric control of Li-C ratio in batter-grade graphites and carbon fibers prior formation of a solid electrolyte interphase. The products' surface chemistries, as probed by XPS, suggest that LiC6 are extremely reactive with trace amounts of moisture or oxygen. The open circuit potential and SEM data show that the reactivity of the lithiated battery-grade graphite and the carbon fiber can be related to the density of edge/defect sites on the surfaces. Preliminary results of spontaneous SEI formation on Li-graphite in electrolyte are also given.

  6. The dependence of natural graphite anode performance on electrode density

    SciTech Connect (OSTI)

    Shim, Joongpyo; Striebel, Kathryn A.

    2003-11-01T23:59:59.000Z

    The effect of electrode density for lithium intercalation and irreversible capacity loss on the natural graphite anode in lithium ion batteries was studied by electrochemical methods. Both the first-cycle reversible and irreversible capacities of the natural graphite anode decreased with an increase in the anode density though compression. The reduction in reversible capacity was attributed to a reduction in the chemical diffusion coefficient for lithium though partially agglomerated particles with a larger stress. For the natural graphite in this study the potentials for Li (de)insertion shifted between the first and second formation cycles and the extent of this shift was dependent on electrode density. The relation between this peak shift and the irreversible capacity loss are probably both due to the decrease in graphite surface area with compression.

  7. ams graphite target: Topics by E-print Network

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

    OF THE BNL, in the first phase of the E951 experiment, graphite and carbon-carbon composite targets were exposed to the AGS materials selected for the experiment are ATJ...

  8. arak iran graphite: Topics by E-print Network

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

    OF THE BNL, in the first phase of the E951 experiment, graphite and carbon-carbon composite targets were exposed to the AGS materials selected for the experiment are ATJ...

  9. astm graphite oxidation: Topics by E-print Network

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

    OF THE BNL, in the first phase of the E951 experiment, graphite and carbon-carbon composite targets were exposed to the AGS materials selected for the experiment are ATJ...

  10. Experimental thermal conductivity and contact conductance of graphite composites 

    E-Print Network [OSTI]

    Jackson, Marian Christine

    1998-01-01T23:59:59.000Z

    Graphite fiber organic matrix composites were reviewed ics. for potential heat sink applications in the electronics packaging determined the effective transverse and longitudinal thermal industry. This experimental investigation conductivity...

  11. The preliminary feasibility of intercalated graphite railgun armatures

    SciTech Connect (OSTI)

    Gaier, J.R. (National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center); Gooden, C.E. (Air Force Armament Lab., Eglin AFB, FL (United States)); Yashan, D. (Cleveland State Univ., OH (United States)); Naud, S. (Naval Coastal Systems Lab., Panama City, FL (United States))

    1991-01-01T23:59:59.000Z

    This paper reports on graphite intercalation compounds which may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  12. Experimental thermal conductivity and contact conductance of graphite composites

    E-Print Network [OSTI]

    Jackson, Marian Christine

    1998-01-01T23:59:59.000Z

    Graphite fiber organic matrix composites were reviewed ics. for potential heat sink applications in the electronics packaging determined the effective transverse and longitudinal thermal industry. This experimental investigation conductivity...

  13. Coal precursors for production of carbon and graphite products. Final report

    SciTech Connect (OSTI)

    Lewis, I.C.; Lewis, R.T.; Mayer, H.K. [Ucar Carbon Co., Inc., Parma, OH (United States)

    1996-04-08T23:59:59.000Z

    The main goal of this program was to demonstrate the utility of coal extracts from the West Virginia University (WVU) extraction process as suitable base raw materials for the carbon products encompassed by the Carbon Products Consortium (CPC) team. These include binder and impregnation pitches, Coke for graphite electrodes, Cokes for anodes and specialty graphite, matrices for C/C composites and raw material for mesophase pitch fibers. Previous work in this program has shown that the WVU coal extraction process coupled with hydrotreatment, does have the potential for achieving this objective. The current effort involved screening and evaluation of extracts produced by the WVU Group and recommending appropriate materials for scaleup for subsequent evaluation by Consortium Team members. The program involved an initial characterization of small-scale extracts using standard analytical methods and mesophase formation studies. This was followed by feedback to the WVU Group and to the CPC partners with recommendation of material for scaleup. Similar analytical and mesophase studies on some of the scaled-up extracts was performed. The activation of the coal extraction residues for the purpose of producing a useful active carbon was investigated. A further task was to fabricate a small graphite artifact using Coke derived from coal extract as the filler and the coal extract itself as a binder. The results of the studies are summarized in this report.

  14. Optimized Operating Range for Large-Format LiFePO4/Graphite Batteries

    SciTech Connect (OSTI)

    Jiang, Jiuchun; Shi, Wei; Zheng, Jianming; Zuo, Pengjian; Xiao, Jie; Chen, Xilin; Xu, Wu; Zhang, Jiguang

    2014-06-01T23:59:59.000Z

    e investigated the long-term cycling performance of large format 20Ah LiFePO4/graphite batteries when they are cycled in various state-of-charge (SOC) ranges. It is found that batteries cycled in the medium SOC range (ca. 20~80% SOC) exhibit superior cycling stability than batteries cycled at both ends (0-20% or 80-100%) of the SOC even though the capcity utilized in the medium SOC range is three times as large as those cycled at both ends of the SOC. Several non-destructive techniques, including a voltage interruption approach, model-based parameter identification, electrode impedance spectra analysis, ?Q/?V analysis, and entropy change test, were used to investigate the performance of LiFePO4/graphite batteries within different SOC ranges. The results reveal that batteries at the ends of SOC exhibit much higher polarization impedance than those at the medium SOC range. These results can be attributed to the significant structural change of cathode and anode materials as revealed by the large entropy change within these ranges. The direct correlation between the polarization impedance and the cycle life of the batteries provides an effective methodology for battery management systems to control and prolong the cycle life of LiFePO4/graphite and other batteries.

  15. Compression induced delamination in a unidirectional graphite/epoxy composite 

    E-Print Network [OSTI]

    Earley, John W.

    1981-01-01T23:59:59.000Z

    December 1981 Major Subject: Civil Engineering COMPRESSION INDUCED DELAMINATION IN A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by JOHN W. EARLEY Approved as to style and content by: (K. L. Jerina, Chairman) (R, A. Schape y', MemP ) W. L.... Bradley, Me er Il. 8 0 1d, O. pa t~tH d December 1981 ABSTRACT Compression Induced Delamination in a Unidirectional Graphite/Epoxy Composite (December 1981) John William Earley, B. S. Aeronautical Engineering California Polytechnic State University...

  16. Slow, stable delamination in graphite/epoxy composites 

    E-Print Network [OSTI]

    Razi, Hamid

    1982-01-01T23:59:59.000Z

    SLOB, STABLE DELAFIINATION IN GRAPHITE/EPOXY COMPOSITES A Thesis by HAMID RA2I Submitted to the Graduate College of Texas ASM University in partial fulfillment of the reouirement for the degree of MASTER OF SCIENCE December 1982 Major... Subject: Mechanical Engineering SLOW, STABLE DELAMINATION IN GRAPHITE/EPOXY COMPOSITES A Thesis by HAMID RAZI Approved as to style and content by: (R. A. Schapery, hair (J. R. Wa ton, Member) (W. L. Bradley, Membe . R. Hopkins, ead of Department...

  17. An investigation of damage accumulation in graphite/epoxy laminates 

    E-Print Network [OSTI]

    Norvell, Robert Gerald

    1985-01-01T23:59:59.000Z

    AN INVESTIGATION OF DAMAGE ACCUMULATION IN GRAPHITE/EPOXY LAMINATES A Thesis by ROBERT GERALD NORVELL Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 1985 Major Subject: Aerospace Engineering AN INVESTIGATION OF DAMAGE ACCUMULATION IN GRAPHITE/EPOXY LAMINATES A Thesis by ROBERT GERALD NORVELL Approved as to style and content by: David H. Allen (Co-Chair of C mmitt. ) Richard A. Schap...

  18. Energy-Efficient Melting and Direct Delivery of High Quality...

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

    Energy-Efficient Melting and Direct Delivery of High Quality Molten Aluminum Energy-Efficient Melting and Direct Delivery of High Quality Molten Aluminum itmdelivery.pdf More...

  19. ITP Metal Casting: Advanced Melting Technologies: Energy Saving...

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

    Advanced Melting Technologies: Energy Saving Concepts and Opportunities for the Metal Casting Industry ITP Metal Casting: Advanced Melting Technologies: Energy Saving Concepts and...

  20. alkali carbonate melts: Topics by E-print Network

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

    8 Glass Transition and Melting Behavior of Carbon Fiber Reinforced Thermoplastic Composite, Studied by Materials Science Websites Summary: Glass Transition and Melting...

  1. Complex systems influence melting of Greenland ice sheet

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

    Complex systems influence melting of Greenland ice sheet Complex systems influence melting of Greenland ice sheet International research team's field work shows that, well, things...

  2. Design of the Next Generation Nuclear Plant Graphite Creep Experiments for Irradiation in the Advanced Test Reactor

    SciTech Connect (OSTI)

    S. Blaine Grover

    2009-05-01T23:59:59.000Z

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six gas reactor graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These graphite irradiations are being accomplished to support development of the next generation reactors in the United States. The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain seven separate stacks of graphite specimens. Six of the specimen stacks will have half of their graphite specimens under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six stacks will be organized into pairs with a different compressive load being applied to the top half of each pair of specimen stacks. The seventh stack will not have a compressive load on the graphite specimens during irradiation. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be the capability of sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during initial start-up of the experiment. The final design phase for the first experiment was completed in September 2008, and the fabrication and assembly of the experiment test train as well as installation and testing of the control and support systems that will monitor and control the experiment during irradiation are being completed in early calendar 2009. The first experiment is scheduled to be ready for insertion in the ATR by April 30, 2009. This paper will discuss the design of the experiment including the test train and the temperature and compressive load monitoring, control, and data collection systems.

  3. Living Expenses (includes approximately

    E-Print Network [OSTI]

    Maroncelli, Mark

    & engineering programs All other programs Graduate: MBA/INFSY at Erie & Harrisburg (12 credits) Business Guarantee 3 (Does not include Dependents Costs4 ) Altoona, Berks, Erie, and Harrisburg 12-Month Estimated

  4. Electrical and thermal properties of graphite/polyaniline composites

    SciTech Connect (OSTI)

    Bourdo, Shawn E., E-mail: sxbourdo@ualr.edu [Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Warford, Brock A.; Viswanathan, Tito [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)] [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)

    2012-12-15T23:59:59.000Z

    A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

  5. Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures

    SciTech Connect (OSTI)

    Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau

    2014-06-01T23:59:59.000Z

    There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.

  6. Melt and vapor characteristics in an electron beam evaporator

    SciTech Connect (OSTI)

    Blumenfeld, L.; Fleche, J.L.; Gonella, C. [DCC/DPE/SPEA Centre d`Etudes de Saclay, Gif-sur-Yvette (France)

    1994-12-31T23:59:59.000Z

    We compare the free surface temperatures T{sub s}, calculated by two methods, in cerium or copper evaporation experiments. The first method considers properties of the melt: by an empirical law we take into account turbulent thermal convection, instabilities and craterization of the free surface. The second method considers the vapor flow expansion and connects T{sub s} to the measured terminal parallel temperature and the terminal mean parallel velocity of the vapor jet, by Direct Simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high craterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that T{sub s} and the Knudsen number at the vapor source reach a threshold when the beam power increases.

  7. Draft report on melt point as a function of composition for urania-based systems

    SciTech Connect (OSTI)

    Valdez, James A [Los Alamos National Laboratory; Byler, Darrin D [Los Alamos National Laboratory

    2012-06-08T23:59:59.000Z

    This report documents the testing of a urania (UO{sub 2.00}) sample as a baseline and the attempt to determine the melt point associated with 4 compositions of urania-ceria and urania-neodymia pseudo binaries provided by ORNL, with compositions of 95/5, and 80/20 and of (U/Ce)O{sub 2.00} and (U/Nd)O{sub 2.00} in the newly developed ceramic melt point determination system. A redesign of the system using parts fabricated from tungsten was undertaken in order to help prevent contamination and tungsten carbide formation in the crucibles. The previously developed system employed mostly graphite parts that were shown to react with the sample containment black-body crucible leading to unstable temperature readings and crucible failure, thus the redesign. Measured melt point values of UO{sub 2.00} and U{sub 0.95}Ce{sub 0.05}O{sub 2.00}, U{sub 0.80}Ce{sub 0.20}O{sub 2.00}, U{sub 0.95}Nd{sub 0.05}O{sub 2.00} and U{sub 0.80}Nd{sub 0.20}O{sub 2.00} were measured using a 2-color pyrometer. The value measured for UO{sub 2.00} was consistent with the published accepted value 2845 C {+-} 25 C, although a wide range of values has been published by researchers and will be discussed later in the text. For comparison, values obtained from a published binary phase diagram of UO{sub 2}-Nd{sub 2}O{sub 3} were used for comparison with our measure values. No literature melt point values for comparison with the measurements performed in this study were found for (U/Ce)O{sub 2.00} in our stoichiometry range.

  8. Approaches to Deal with Irradiated Graphite in Russia - Proposal for New IAEA CRP on Graphite Waste Management - 12364

    SciTech Connect (OSTI)

    Kascheev, Vladimir; Poluektov, Pavel; Ustinov, Oleg [JSC 'VNIINM', Center of SNF and RW Management, 5A Rogova st., Moscow 123060 (Russian Federation)

    2012-07-01T23:59:59.000Z

    The problems of spent reactor graphite are being shown, the options of its disposal is considered. Burning method is selected as the most efficient and waste-free. It is made a comparison of amounts of {sup 14}C that entering the environment in a natural way during the operation of nuclear power plants (NPPs) and as a result of the proposed burning of spent reactor graphite. It is shown the possibility of burning graphite with the arrival of {sup 14}C into the atmosphere within the maximum allowable emissions. This paper analyzes the different ways of spent reactor graphite treatment. It is shown the possibility of its reprocessing by burning method in the air flow. It is estimated the effect of this technology to the overall radiation environment and compared its contribution to the general background radiation due to cosmic radiation and NPPs emission. It is estimated the maximum permissible speeds of burning reactor graphite (for example, RBMK graphite) for areas with different conditions of agricultural activities. (authors)

  9. Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Melting Efficiency Improvement

    SciTech Connect (OSTI)

    Principal Investigator Kent Peaslee; Co-PIà ƒ  ¢Ã ‚  € à ‚  ™ s: Von Richards, Jeffrey Smith

    2012-07-31T23:59:59.000Z

    Steel foundries melt recycled scrap in electric furnaces and typically consume 35-100% excess energy from the theoretical energy requirement required to pour metal castings. This excess melting energy is multiplied by yield losses during casting and finishing operations resulting in the embodied energy in a cast product typically being three to six times the theoretical energy requirement. The purpose of this research project was to study steel foundry melting operations to understand energy use and requirements for casting operations, define variations in energy consumption, determine technologies and practices that are successful in reducing melting energy and develop new melting techniques and tools to improve the energy efficiency of melting in steel foundry operations.

  10. PURIFICATION OF IRIDIUM BY ELECTRON BEAM MELTING

    SciTech Connect (OSTI)

    Ohriner, Evan Keith [ORNL

    2008-01-01T23:59:59.000Z

    The purification of iridium metal by electron beam melting has been characterized for 48 impurity elements. Chemical analysis was performed by glow discharge mass spectrographic (GDMS) analysis for all elements except carbon, which was analyzed by combustion. The average levels of individual elemental impurities in the starting powder varied from 37 g/g to 0.02 g/g. The impurity elements Li, Na, Mg, P, S, Cl, K, Ca, Mn, Co, Ni, Cu, Zn, As, Pd, Ag, Cd, Sn, Sb, Te, Ba, Ce, Tl, Pb, and Bi were not detectable following the purification. No significant change in concentration of the elements Ti, V, Zr, Nb, Mo, and Re was found. The elements B, C, Al, Si, Cr, Fe, Ru, Rh, and Pt were partially removed by vaporization during electron beam melting. Langmuir's equation for ideal vaporization into a vacuum was used to calculate for each impurity element the expected ratio of impurity content after melting to that before melting. Equilibrium vapor pressures were calculated using Henry's law, with activity coefficients obtained from published data for the elements Fe, Ti, and Pt. Activity coefficients were estimated from enthalpy data for Al, Si, V, Cr, Mn, Co, Ni, Zr, Nb, Mo, and Hf and an ideal solution model was used for the remaining elements. The melt temperature was determined from measured iridium weight loss. Excellent agreement was found between measured and calculated impurity ratios for all impurity elements. The results are consistent with some localized heating of the melt pool due to rastering of the electron beam, with an average vaporization temperature of 3100 K as compared to a temperature of 2965 K calculated for uniform heating of the melt pool. The results are also consistent with ideal mixing in the melt pool.

  11. SILICATE MELT PROPERTIES AND VOLCANIC Youxue Zhang,1,2

    E-Print Network [OSTI]

    Zhang, Youxue

    SILICATE MELT PROPERTIES AND VOLCANIC ERUPTIONS Youxue Zhang,1,2 Zhengjiu Xu,2 Mengfan Zhu,1 2007. [1] Knowledge about the properties of silicate melts is needed by volcanologists and petrologists and diffusivity of volatile components in silicate melts, silicate melt viscosity, and the fragmentation condition

  12. Consequences of diffusive reequilibration for the interpretation of melt inclusions

    E-Print Network [OSTI]

    Langmuir, Charles H.

    are commonly used to interpret melting and melt extraction processes. These interpretations, however, often-diffusing elements with high mineral/melt partition coefficients are modified rapidly, particularly in small inclusions. Because minerals have very different Dmineral/melt for the various elements, the effects

  13. Treatment of Irradiated Graphite from French Bugey Reactor - 13424

    SciTech Connect (OSTI)

    Brown, Thomas [Studsvik, Inc., 5605 Glenridge Drive NE, Suite 705, Atlanta, GA (United States)] [Studsvik, Inc., 5605 Glenridge Drive NE, Suite 705, Atlanta, GA (United States); Poncet, Bernard [electricite de France, 154 Avenue Thiers, CS 60018, 69458 Lyon Cedex 06 (France)] [electricite de France, 154 Avenue Thiers, CS 60018, 69458 Lyon Cedex 06 (France)

    2013-07-01T23:59:59.000Z

    Beginning in 2009, in order to determine an alternative to direct disposal for decommissioned irradiated graphite from EDF's Bugey NPP, Studsvik and EDF began a test program to determine if graphite decontamination and destruction were practicable using Studsvik's thermal organic reduction (THOR) technology. The testing program focused primarily on the release of C-14, H-3, and Cl-36 and also monitored graphite mass loss. For said testing, a bench-scale steam reformer (BSSR) was constructed with the capability of flowing various compositions of gases at temperatures up to 1300 deg. C over uniformly sized particles of graphite for fixed amounts of time. The BSSR was followed by a condenser, thermal oxidizer, and NaOH bubbler system designed to capture H-3 and C-14. Also, in a separate series of testing, high concentration acid and peroxide solutions were used to soak the graphite and leach out and measure Cl-36. A series of gasification tests were performed to scope gas compositions and temperatures for graphite gasification using steam and oxygen. Results suggested higher temperature steam (1100 deg. C vs. 900 deg. C) yielded a practicable gasification rate but that lower temperature (900 deg. C) gasification was also a practicable treatment alternative if oxygen is fed into the process. A series of decontamination tests were performed to determine the release behavior of and extent to which C-14 and H-3 were released from graphite in a high temperature (900-1300 deg. C), low flow roasting gas environment. In general, testing determined that higher temperatures and longer roasting times were efficacious for releasing H-3 completely and the majority (80%) of C-14. Manipulating oxidizing and reducing gas environments was also found to limit graphite mass loss. A series of soaking tests was performed to measure the amount of Cl-36 in the samples of graphite before and after roasting in the BSSR. Similar to C-14 release, these soaking tests revealed that 70-80% Cl-36 is released during roasting tests. (authors)

  14. Method for wetting a boron alloy to graphite

    DOE Patents [OSTI]

    Storms, E.K.

    1987-08-21T23:59:59.000Z

    A method is provided for wetting a graphite substrate and spreading a a boron alloy over the substrate. The wetted substrate may be in the form of a needle for an effective ion emission source. The method may also be used to wet a graphite substrate for subsequent joining with another graphite substrate or other metal, or to form a protective coating over a graphite substrate. A noneutectic alloy of boron is formed with a metal selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt) with excess boron, i.e., and atomic percentage of boron effective to precipitate boron at a wetting temperature of less than the liquid-phase boundary temperature of the alloy. The alloy is applied to the substrate and the graphite substrate is then heated to the wetting temperature and maintained at the wetting temperature for a time effective for the alloy to wet and spread over the substrate. The excess boron is evenly dispersed in the alloy and is readily available to promote the wetting and spreading action of the alloy. 1 fig.

  15. Ultra slow EB melting to reduce reactor cladding

    SciTech Connect (OSTI)

    Worcester, S.A.; Woods, C.R.; Galer, G.S.; Propst, R.L.

    1989-03-28T23:59:59.000Z

    A process is described for making an electron beam melted fuel element liner material from sponge zirconium, the process comprising: electron beam melting sponge zirconium at a melting rate of less than 1 inch per hour to form an electron beam melted zirconium material containing less than 300 ppm iron, less than 400 ppm oxygen, and less than 5 ppm aluminum; and alloying the electron beam melted zirconium in a vacuum arc furnace with 0.1-2.0 weight percent of tin.

  16. Electroanalytical applications of screen-printable surfactant-induced sol-gel graphite composites

    DOE Patents [OSTI]

    Guadalupe, Ana R. (San Juan, PR); Guo, Yizhu (San Juan, PR)

    2001-05-15T23:59:59.000Z

    A process for preparing sol-gel graphite composite electrodes is presented. This process preferably uses the surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) and eliminates the need for a cosolvent, an acidic catalyst, a cellulose binder and a thermal curing step from prior art processes. Fabrication of screen-printed electrodes by this process provides a simple approach for electroanalytical applications in aqueous and nonaqueous solvents. Examples of applications for such composite electrodes produced from this process include biochemical sensors such as disposable, single-use glucose sensors and ligand modified composite sensors for metal ion sensitive sensors.

  17. Energy Saving Melting and Revert Reduction Technology: Melting Efficiency in Die Casting Operations

    SciTech Connect (OSTI)

    David Schwam

    2012-12-15T23:59:59.000Z

    This project addressed multiple aspects of the aluminum melting and handling in die casting operations, with the objective of increasing the energy efficiency while improving the quality of the molten metal. The efficiency of melting has always played an important role in the profitability of aluminum die casting operations. Consequently, die casters need to make careful choices in selecting and operating melting equipment and procedures. The capital cost of new melting equipment with higher efficiency can sometimes be recovered relatively fast when it replaces old melting equipment with lower efficiency. Upgrades designed to improve energy efficiency of existing equipment may be well justified. Energy efficiency is however not the only factor in optimizing melting operations. Melt losses and metal quality are also very important. Selection of melting equipment has to take into consideration the specific conditions at the die casting shop such as availability of floor space, average quantity of metal used as well as the ability to supply more metal during peaks in demand. In all these cases, it is essential to make informed decisions based on the best available data.

  18. Effect of Graphitic Content on Carbon Supported Catalyst Performance

    SciTech Connect (OSTI)

    A. Patel; K. Artyushkova; P. Atanassov; David Harvey; M. Dutta; V. Colbow; S. Wessel

    2011-07-01T23:59:59.000Z

    The effect of graphitic content on carbon supported platinum catalysts was investigated in order to investigate its influence on catalyst performance. Four catalysts of varying surface areas and graphitic content were analyzed using XPS, HREELS, and tested using RDE experiments. The catalysts were also heat treated at 150 C and 100%RH as means to uniformly age them. The heat treated samples were analyzed using the same methods to determine what changes had occurred due to this aging process. When compared to the BOL catalysts, heat treated catalysts displayed increased graphitic carbon and platinum metallic content, however they also showed depressed catalytic activity. The primary cause is still under investigation, though it is believed to be related to loss of amorphous carbon content.

  19. Effect of Vinylene Carbonate on Graphite Anode Cycling Efficiency

    SciTech Connect (OSTI)

    Ridgway, Paul; Zheng, Honghe; Liu, Gao; Song, Xiangun; Ross, Philip; Battaglia, Vincent

    2009-05-05T23:59:59.000Z

    Vinylene Carbonate (VC) was added to the electrolyte in graphite-lithium half-cells. We report its effect on the coulombic efficiency (as capacity shift) of graphite electrodes under various formation cycling conditions. Cyclic voltammetry on glassy carbon showed that VC passivates the electrode against electrolyte reduction. The dQ/dV plots of the first lithiation of the graphite suggest that VC alters the SEI layer, and that by varying the cell formation rate, the initial ratio of ethylene carbonate to VC in the SEI layer can be controlled. VC was found to decrease first cycle efficiency and reversible capacity (in ongoing cycling) when used to excess. However, experiments with VC additive used with various formation rates did not show any decrease in capacity shift.

  20. Graphite Foams for Lithium-Ion Battery Current Collectors

    SciTech Connect (OSTI)

    Dudney, Nancy J [ORNL; Tiegs, Terry N [ORNL; Kiggans, Jim [ORNL; Jang, Young-Il [ORNL; Klett, James William [ORNL

    2007-01-01T23:59:59.000Z

    Graphite open-cell foams, with their very high electronic and thermal conductivities, may serve as high surface area and corrosion resistant current collectors for lithium-ion batteries. As a proof of principle, cathodes were prepared by sintering carbon-coated LiFePO4 particles into the porous graphite foams. Cycling these cathodes in a liquid electrolyte cell showed promising performance even for materials and coatings that have not been optimized. The specific capacity is not limited by the foam structure, but by the cycling performance of the coated LiFePO4 particles. Upon extended cycling for more than 100 deep cycles, no loss of capacity is observed for rates of C/2 or less. The uncoated graphite foams will slowly intercalate lithium reversibly at potentials less than 0.2 volts versus lithium.

  1. Graphit-ceramic RF Faraday-thermal shield and plasma limiter

    DOE Patents [OSTI]

    Hwang, David L. (Princeton Junction, NJ); Hosea, Joel C. (Princeton, NJ)

    1989-01-01T23:59:59.000Z

    The present invention is directed to a process of brazing a ceramic mater to graphite. In particular, the brazing procedure is directed to the production of a novel brazed ceramic graphite product useful as a Faraday shield.

  2. Enhanced performance of graphite anode materials by AlF3 coating...

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

    performance of graphite anode materials by AlF3 coating for lithium-ion batteries. Enhanced performance of graphite anode materials by AlF3 coating for lithium-ion batteries....

  3. Chemical and Physical Modification of Graphitic Materials by Oxidative Processes and Solvent Intercalation 

    E-Print Network [OSTI]

    Werke, Carrie Beth

    2014-08-27T23:59:59.000Z

    Graphene and graphite are materials of high interest for many applications. In order to increase the possible uses of these materials, more must be understood about how their properties can be modified. One way to modify graphitic properties...

  4. Low-Cost Graphite and Olivine-Based Materials for Li-Ion Batteries...

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

    Graphite and Olivine-Based Materials for Li-Ion Batteries Low-Cost Graphite and Olivine-Based Materials for Li-Ion Batteries Presentation from the U.S. DOE Office of Vehicle...

  5. The evaluation of cleanness by electron beam button melting and other methods - a review

    SciTech Connect (OSTI)

    Quested, P.N.; Hayes, D.M. [National Physical Lab., Middlesex (United Kingdom)

    1994-12-31T23:59:59.000Z

    The accurate determination of both the number and size distribution of inclusions in superclean materials is difficult. Some of the methods used for nickel-base alloys and steels are briefly reviewed; all the methods have problems associated with them. Electron Beam Button Melting (EBBM) and the new technique of Cold Crucible Melting (CCM) as methods of concentrating the inclusions offer the advantage of sampling large volumes of material quickly. The number, size and composition of the entrapped particles can be determined using Scanning Electron Microscopy, (SEM). Both techniques may be used for semi-quantitative assessment such as ranking different heats of materials but care is required with quantitative evaluation. The mechanisms controlling inclusion collection efficiency for EBBM are reviewed including investigations with samples doped with particles of known size and number and assessing recovery rates on button rafts. In EBBM low power melting and solidification programmes are recommended to minimise the melting or sintering of the inclusions and melt compositions, particularly sulphur, have a major effect on the efficiency of inclusion collection. Under favourable conditions collection efficiencies of 90-95% can be achieved. As a result of these types of studies a draft code of practice for the evaluation of alloy cleanness by EBBM has been prepared. Cold crucible melting is an attractive alternative to EBBM for cleanness evaluation. Trials have established that collection efficiencies of 80-85% can be achieved with this method but SEM examination of the buttons is more time consuming compared with EBBM.

  6. Investigation of MSWI fly ash melting characteristic by DSC-DTA

    SciTech Connect (OSTI)

    Li, Rundong [Institute of Clean Energy and Environmental Engineering, Liaoning Key Laboratory of Clean Energy, Shenyang Institute of Aeronautical Engineering, Shenyang 110136 (China)], E-mail: leerd@mail.tsinghua.edu.cn; Wang, Lei; Yang, Tianhua; Raninger, Bernhard [Institute of Clean Energy and Environmental Engineering, Liaoning Key Laboratory of Clean Energy, Shenyang Institute of Aeronautical Engineering, Shenyang 110136 (China)

    2007-07-01T23:59:59.000Z

    The melting process of MSWI (Municipal Solid Waste Incineration) fly ash has been studied by high-temperature DSC-DTA experiments. The experiments were performed at a temperature range of 20-1450 deg. C, and the considerable variables included atmosphere (O{sub 2} and N{sub 2}), heating rates (5 deg. C/min, 10 deg. C/min, 20 deg. C/min) and CaO addition. Three main transitions were observed during the melting process of fly ash: dehydration, polymorphic transition and fusion, occurring in the temperature range of 100-200 deg. C, 480-670 deg. C and 1101-1244 deg. C, respectively. The apparent heat capacity and heat requirement for melting of MSWI fly ash were obtained by DSC (Differential Scanning Calorimeter). A thermodynamic modeling to predict the heat requirements for melting process has been presented, and it agrees well with the experimental data. Finally, a zero-order kinetic model of fly ash melting transition was established. The apparent activation energy of MSWI fly ash melting transition was obtained.

  7. Microfabrication of freestanding metal structures released from graphite substrates.

    SciTech Connect (OSTI)

    Makarova, O. V.; Tang, C.-M.; Mancini, D. C.; Moldovan, N.; Divan, R.; Ryding, D. G.; Lee, R. H.

    2002-02-22T23:59:59.000Z

    A sacrificial layer is usually used to release electroformed microstructures. Because of the chemistry applied to the sacrificial layer, only a limited number of metals can be used for electroforming. A novel method to fabricate freestanding electroformed copper structures is presented. A graphite substrate allows the release of the metal part, by abrasive removal of the graphite after electroforming. Results on fabrication of high-aspect-ratio freestanding copper grids are presented; these can be used as x-ray collimator in medical imaging to reduce scattered radiation. This process has potential application to the fabrication of injection molds and microparts on pick-and-place carriers for microelectromechanical systems (MEMS).

  8. Equation of State of Graphite-like BC,

    SciTech Connect (OSTI)

    Solozhenko,V.; Kurakevych, O.; Solozhenko, E.; Chen, J.; Parise, J.

    2006-01-01T23:59:59.000Z

    The compressibility of turbostratic boron-substituted graphite (t-BC) was measured up to 12 GPa at room temperature using energy-dispersive X-ray powder diffraction with synchrotron radiation. A fit to the experimental p-V data using Birch-Murnaghan equation of state gives values of the t-BC bulk modulus 23(2) GPa and its pressure derivative 8.0(6). These values point to a higher compressibility of t-BC as compared to turbostratic graphite.

  9. Delamination fracture toughness of a unidirectional graphite/epoxy composite 

    E-Print Network [OSTI]

    Hulsey, Roy Charles

    1980-01-01T23:59:59.000Z

    DELAMINATION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOS ITE A Thesis by ROY CHARLES HULSEY Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1980 Major Subject: Mechanical Engineering DELAMINA. ION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by ROY CHARLES HULSEY Approved as to sty1e and content by: +alter L. Brad1ey, C airman TR. A. S p...

  10. Gelcasting polymeric precursors for producing net-shaped graphites

    DOE Patents [OSTI]

    Klett, James W. (Knoxville, TN); Janney, Mark A. (Knoxville, TN)

    2002-01-01T23:59:59.000Z

    The present invention discloses a method for molding complex and intricately shaped high density monolithic carbon, carbon-carbon, graphite, and thermoplastic composites using gelcasting technology. The method comprising a polymeric carbon precursor, a solvent, a dispersant, an anti-foaming agent, a monomer system, and an initiator system. The components are combined to form a suspension which is poured into a mold and heat-treated to form a thermoplastic part. The thermoplastic part can then be further densified and heat-treated to produce a high density carbon or graphite composite. The present invention also discloses the products derived from this method.

  11. Gelcasting polymeric precursors for producing net-shaped graphites

    DOE Patents [OSTI]

    Klett, James W.; Janney, Mark A.

    2005-02-15T23:59:59.000Z

    The present invention discloses a method for molding complex and intricately shaped high density monolithic carbon, carbon-carbon, graphite, and thermoplastic composites using gelcasting technology. The method comprising a polymeric carbon precursor, a solvent, a dispersant, an anti-foaming agent, a monomer system, and an initiator system. The components are combined to form a suspension which is poured into a mold and heat-treated to form a thermoplastic part. The thermoplastic part can then be further densified and heat-treated to produce a high density carbon or graphite composite. The present invention also discloses the products derived from this method.

  12. Performance of Lithium Ion Cell Anode Graphites Under Various Cycling Conditions

    E-Print Network [OSTI]

    Ridgway, Paul

    2010-01-01T23:59:59.000Z

    graphite formulations in particular, are the current standard for lithium-ion anodes for electric vehicle batteries(

  13. Scrap uranium recycling via electron beam melting

    SciTech Connect (OSTI)

    McKoon, R.

    1993-11-01T23:59:59.000Z

    A program is underway at the Lawrence Livermore National Laboratory (LLNL) to recycle scrap uranium metal. Currently, much of the material from forging and machining processes is considered radioactive waste and is disposed of by oxidation and encapsulation at significant cost. In the recycling process, uranium and uranium alloys in various forms will be processed by electron beam melting and continuously cast into ingots meeting applicable specifications for virgin material. Existing vacuum processing facilities at LLNL are in compliance with all current federal and state environmental, safety and health regulations for the electron beam melting and vaporization of uranium metal. One of these facilities has been retrofitted with an auxiliary electron beam gun system, water-cooled hearth, crucible and ingot puller to create an electron beam melt furnace. In this furnace, basic process R&D on uranium recycling will be performed with the goal of eventual transfer of this technology to a production facility.

  14. A model for melting of confined DNA

    E-Print Network [OSTI]

    Werner, E; Ambjörnsson, T; Mehlig, B

    2015-01-01T23:59:59.000Z

    When DNA molecules are heated they denature. This occurs locally so that loops of molten single DNA strands form, connected by intact double-stranded DNA pieces. The properties of this "melting" transition have been intensively investigated. Recently there has been a surge of interest in this question, caused by experiments determining the properties of partially bound DNA confined to nanochannels. But how does such confinement affect the melting transition? To answer this question we introduce, and solve a model predicting how confinement affects the melting transition for a simple model system by first disregarding the effect of self-avoidance. We find that the transition is smoother for narrower channels. By means of Monte-Carlo simulations we then show that a model incorporating self-avoidance shows qualitatively the same behaviour and that the effect of confinement is stronger than in the ideal case.

  15. Low melting high lithia glass compositions and methods

    DOE Patents [OSTI]

    Jantzen, Carol M. (Aiken, SC); Pickett, John B. (Aiken, SC); Cicero-Herman, Connie A. (Aiken, SC); Marra, James C. (Aiken, SC)

    2000-01-01T23:59:59.000Z

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  16. Low melting high lithia glass compositions and methods

    DOE Patents [OSTI]

    Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

    2004-11-02T23:59:59.000Z

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  17. Low melting high lithia glass compositions and methods

    DOE Patents [OSTI]

    Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

    2003-10-07T23:59:59.000Z

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  18. Status of ASME Section III Task Group on Graphite Support Core Structures

    SciTech Connect (OSTI)

    Robert L. Bratton; Tim D. Burchell

    2005-08-01T23:59:59.000Z

    This report outlines the roadmap that the ASME Project Team on Graphite Core Supports is pursuing to establish design codes for unirradiated and irradiated graphite core components during its first year of operation. It discusses the deficiencies in the proposed Section III, Division 2, Subsection CE graphite design code and the different approaches the Project Team has taken to address those deficiencies.

  19. Non-oxidative intercalation and exfoliation of graphite by Brnsted acids

    E-Print Network [OSTI]

    Non-oxidative intercalation and exfoliation of graphite by Brønsted acids Nina I. Kovtyukhova1 and the polarizable graphene sheets. The intercalated graphites readily exfoliate in dimethylformamide to give, with loss of conductivity9,10. These highly oxidized graphite compounds can be exfoliated to form

  20. Rock melting tool with annealer section

    DOE Patents [OSTI]

    Bussod, Gilles Y. (Santa Fe, NM); Dick, Aaron J. (Oakland, CA); Cort, George E. (Montrose, CO)

    1998-01-01T23:59:59.000Z

    A rock melting penetrator is provided with an afterbody that rapidly cools a molten geological structure formed around the melting tip of the penetrator to the glass transition temperature for the surrounding molten glass-like material. An annealing afterbody then cools the glass slowly from the glass transition temperature through the annealing temperature range to form a solid self-supporting glass casing. This allows thermally induced strains to relax by viscous deformations as the molten glass cools and prevents fracturing of the resulting glass liner. The quality of the glass lining is improved, along with its ability to provide a rigid impermeable casing in unstable rock formations.

  1. Pressurized melt ejection into scaled reactor cavities

    SciTech Connect (OSTI)

    Tarbell, W.W.; Pilch, M.; Brockmann, J.E.; Ross, J.W.; Gilbert, D.W.

    1986-10-01T23:59:59.000Z

    This report describes four tests performed in the High-Pressure Melt Streaming Program (HIPS) using linear-scaled cavities of the Zion Nuclear Power Plant. These experiments were conducted to study the phenomena involved in high-pressure ejection of core debris into the cavity beneath the reactor pressure vessel. One-tenth and one-twentieth linear scale models of reactor cavities were constructed and instrumented. The first test used an apparatus constructed of alumina firebrick to minimize the potential interaction between the ejected melt and cavity material. The remaining three experiments used scaled representations of the Zion nuclear plant geometry, constructed of prototypic concrete composition.

  2. Method and apparatus for melting metals

    DOE Patents [OSTI]

    Moore, Alan F.; Schechter, Donald E.; Morrow, Marvin Stanley

    2006-03-14T23:59:59.000Z

    A method and apparatus for melting metals uses microwave energy as the primary source of heat. The metal or mixture of metals are placed in a ceramic crucible which couples, at least partially, with the microwaves to be used. The crucible is encased in a ceramic casket for insulation and placed within a microwave chamber. The chamber may be evacuated and refilled to exclude oxygen. After melting, the crucible may be removed for pouring or poured within the chamber by dripping or running into a heated mold within the chamber. Apparent coupling of the microwaves with softened or molten metal produces high temperatures with great energy savings.

  3. Brazing of ceramic and graphite to metal in the fabrication of ICRF (ion cyclotron range of frequencies) antenna and feedthrough components

    SciTech Connect (OSTI)

    Schechter, D.E.; Sluss, F.; Hoffman, D.J.

    1987-01-01T23:59:59.000Z

    Fabrication of some of the more critical components of ion cyclotron range of frequencies (ICRF) antenna and feedthrough assemblies has involved the brazing of alumina ceramic and graphite to various metals. Copper end pieces have been successfully brazed to alumina cylinders for use in feedthroughs for TEXTOR and in feedthroughs and capacitors for a Tokamak Fusion Test Reactor (TFTR) antenna. Copper-plated Inconel rods and tubes have been armored with graphite for construction of Faraday shields on antennas for Doublet III-D and TFTR. Details of brazing procedures and test results, including rf performance, mechanical strength, and thermal capabilities, are presented. 14 figs.

  4. Method for melting glass by measurement of non-bridging oxygen

    DOE Patents [OSTI]

    Jantzen, Carol M. (3922 Wood Valley Dr., Aiken, SC 29801)

    1992-01-01T23:59:59.000Z

    A method for making better quality molten glass in a glass melter, the glass having the desired viscosity and, preferably, also the desired resistivity so that the glass melt can be established effectively and the product of the glass melter will have the desired level of quality. The method includes the adjustment of the composition of the glass constituents that are fed into the melter in accordance with certain correlations that reliably predict the viscosity and resistivity from the melter temperature and the melt composition, then heating the ingredients to the melter's operating temperature until they melt and homogenize. The equations include the calculation of a "non-bridging oxygen" term from the numbers of moles of the various ingredients, and then the determination of the viscosity and resistivity from the operating temperature of the melter and the non-bridging oxygen term.

  5. Method for melting glass by measurement of non-bridging oxygen

    DOE Patents [OSTI]

    Jantzen, C.M.

    1992-04-07T23:59:59.000Z

    A method is described for making better quality molten glass in a glass melter, the glass having the desired viscosity and, preferably, also the desired resistivity so that the glass melt can be established effectively and the product of the glass melter will have the desired level of quality. The method includes the adjustment of the composition of the glass constituents that are fed into the melter in accordance with certain correlations that reliably predict the viscosity and resistivity from the melter temperature and the melt composition, then heating the ingredients to the melter's operating temperature until they melt and homogenize. The equations include the calculation of a non-bridging oxygen' term from the numbers of moles of the various ingredients, and then the determination of the viscosity and resistivity from the operating temperature of the melter and the non-bridging oxygen term. 4 figs.

  6. Krypton adsorption on (0001) graphite pre-plated with cyclohexane

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    91 Krypton adsorption on (0001) graphite pre-plated with cyclohexane A. Razafitianamaharavo (1), N étudiée par volumétrie entre 71 et 83 K. L'adsorption de krypton, fortement inhibée par la présence du physisorbed has been studied between 71 and 83 K by means of classical volumetric methods. Krypton adsorption

  7. A neutron diffraction study of nano-crystalline graphite oxide

    E-Print Network [OSTI]

    and regions containing oxidized chain-like structures. The neutron scattering pair distribution function is heterogeneous, the total neutron scattering data presented in this paper gives a statistically averagedA neutron diffraction study of nano-crystalline graphite oxide J.A. Johnsona,b,*, C.J. Benmoreb , S

  8. Author's personal copy Reactivity of lithium exposed graphite surface

    E-Print Network [OSTI]

    Harilal, S. S.

    on the surface [18]. Hence the effect of lithium on plasma­wall interactions is expected to dependAuthor's personal copy Reactivity of lithium exposed graphite surface S.S. Harilal a, *, J in fusion devices [1­5]. For example, wall conditioning with thin lithium layers gives rise to low hydrogen

  9. Progress in Developing Finite Element Models Replicating Flexural Graphite Testing

    SciTech Connect (OSTI)

    Robert Bratton

    2010-06-01T23:59:59.000Z

    This report documents the status of flexural strength evaluations from current ASTM procedures and of developing finite element models predicting the probability of failure. This work is covered under QLD REC-00030. Flexural testing procedures of the American Society for Testing and Materials (ASTM) assume a linear elastic material that has the same moduli for tension and compression. Contrary to this assumption, graphite is known to have different moduli for tension and compression. A finite element model was developed and demonstrated that accounts for the difference in moduli tension and compression. Brittle materials such as graphite exhibit significant scatter in tensile strength, so probabilistic design approaches must be used when designing components fabricated from brittle materials. ASTM procedures predicting probability of failure in ceramics were compared to methods from the current version of the ASME graphite core components rules predicting probability of failure. Using the ASTM procedures yields failure curves at lower applied forces than the ASME rules. A journal paper was published in the Journal of Nuclear Engineering and Design exploring the statistical models of fracture in graphite.

  10. THORIUM FUEL CYCLES: A GRAPHITE-MODERATED MOLTEN SALT REACTOR

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    THORIUM FUEL CYCLES: A GRAPHITE-MODERATED MOLTEN SALT REACTOR VERSUS A FAST SPECTRUM SOLID FUEL is to compare two main options dedicated to long-term energy production with Thorium: solid fuel with fast its be- haviour until it reaches the 232Th/233U equilibrium from two di erent starting fuels: 232Th

  11. Nuclear reactor melt-retention structure to mitigate direct containment heating

    DOE Patents [OSTI]

    Tutu, Narinder K. (Manorville, NY); Ginsberg, Theodore (East Setauket, NY); Klages, John R. (Mattituck, NY)

    1991-01-01T23:59:59.000Z

    A light water nuclear reactor melt-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten core material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the melt-retention chamber there is provided a passageway that includes molten core droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten core droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the melt-retention structure to direct the flow of molten core material and help retain it within the melt-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the melt-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten core droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.

  12. Pulsed-electron-beam melting of Fe

    SciTech Connect (OSTI)

    Knapp, J.A.; Follstaedt, D.M.

    1981-01-01T23:59:59.000Z

    Pulsed (50 nsec) electron beams with deposited energies of 1.1 to 2.3 J/cm/sup 2/ have been used to rapidly melt a surface layer of Fe. Calculations show that this range of energies produces melt depths from 0.4 to 1.2 ..mu..m and melt times of 100 to 500 nsec. Optical microscopy and SEM of pulse treated polycrystalline foils show slip traces, as well as a general smoothing of surface features which shows that melting has occurred. TEM shows that the resolidified material is bcc, and that the material within a grain is epitaxial with the substrate. TEM also shows slip traces along (110) planes, as well as a high density of dislocations, both extended and loop. At the highest energy, subgrain boundaries are observed. Some samples were implanted with 1 x 10/sup 16/ Sn/cm/sup 2/ at 150 keV. After pulse treatment, the Sn depth profile was observed to have broadened, consistent with liquid phase diffusion. The Sn had the unexpected effect of suppressing slip at the sample surface.

  13. Analysis of an EBeam melting process

    SciTech Connect (OSTI)

    Schunk, P.R.

    1991-01-01T23:59:59.000Z

    Electron-Beam (EBeam) melting furnaces are routinely used to minimize the occurrence of second-phase particles in the processing of segregation-sensitive alloys. As one part of the process, a circulating electron beam impinges the surface of a crucible melt pool to help control the shape of the solidification front below. By modeling melt pool hydrodynamics, heat transfer, and the shape of solidification boundaries, we plan to optimize the dwell pattern of the beam so that the material solidifies with a composition as spatially homogeneous as possible. Both two-and three-dimensional models are being pursued with FIDAP 5.02, the former serving as a test bed for various degrees of model sophistication. A heat flux distribution is specified on the top of the domain to simulate the EBeam dwell pattern. In two dimensions it is found that an inertially-driven recirculation in the melt pool interacts with a counter-rotating buoyancy-driven recirculation, and that both recirculation influence heavily the shape of the solidification front. In three dimensions the inertial cell decays quickly with distance from the position of the inlet stream. Because the Rayleigh number can exceed 10{sup 7} for materials and operating conditions of interest, stability and the possibility of spontaneous transients are explored. 1 refs., 3 figs.

  14. Energy Savings in Electric Arc Furnace Melting

    E-Print Network [OSTI]

    Lubbeck, W.

    1982-01-01T23:59:59.000Z

    Arc furnace melting which at one time was almost exclusively used to produce alloy steel and steel castings is now widely accepted in the industry as an efficient process to produce all types of steel and iron. Presently, about 28% of steel...

  15. Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

    DOE Patents [OSTI]

    Makowiecki, Daniel M. (Livermore, CA); Ramsey, Philip B. (Livermore, CA); Juntz, Robert S. (Hayward, CA)

    1995-01-01T23:59:59.000Z

    An improved method for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite's high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding.

  16. Melt spreading code assessment, modifications, and application to the EPR core catcher design.

    SciTech Connect (OSTI)

    Farmer, M. T .; Nuclear Engineering Division

    2009-03-30T23:59:59.000Z

    The Evolutionary Power Reactor (EPR) is under consideration by various utilities in the United States to provide base load electrical production, and as a result the design is undergoing a certification review by the U.S. Nuclear Regulatory Commission (NRC). The severe accident design philosophy for this reactor is based upon the fact that the projected power rating results in a narrow margin for in-vessel melt retention by external cooling of the reactor vessel. As a result, the design addresses ex-vessel core melt stabilization using a mitigation strategy that includes: (1) an external core melt retention system to temporarily hold core melt released from the vessel; (2) a layer of 'sacrificial' material that is admixed with the melt while in the core melt retention system; (3) a melt plug in the lower part of the retention system that, when failed, provides a pathway for the mixture to spread to a large core spreading chamber; and finally, (4) cooling and stabilization of the spread melt by controlled top and bottom flooding. The overall concept is illustrated in Figure 1.1. The melt spreading process relies heavily on inertial flow of a low-viscosity admixed melt to a segmented spreading chamber, and assumes that the melt mass will be distributed to a uniform height in the chamber. The spreading phenomenon thus needs to be modeled properly in order to adequately assess the EPR design. The MELTSPREAD code, developed at Argonne National Laboratory, can model segmented, and both uniform and nonuniform spreading. The NRC is thus utilizing MELTSPREAD to evaluate melt spreading in the EPR design. MELTSPREAD was originally developed to support resolution of the Mark I containment shell vulnerability issue. Following closure of this issue, development of MELTSPREAD ceased in the early 1990's, at which time the melt spreading database upon which the code had been validated was rather limited. In particular, the database that was utilized for initial validation consisted of: (1) comparison to an analytical solution for the dam break problem, (2) water spreading tests in a 1/10 linear scale model of the Mark I containment by Theofanous et al., and (3) steel spreading tests by Suzuki et al. that were also conducted in a geometry similar to the Mark I. The objective of this work was to utilize the MELTSPREAD code to check the assumption of uniform melt spreading in the EPR core catcher design. As a starting point for the project, the code was validated against the worldwide melt spreading database that emerged after the code was originally written in the very early 1990's. As part of this exercise, the code was extensively modified and upgraded to incorporate findings from these various analytical and experiment programs. In terms of expanding the ability of the code to analyze various melt simulant experiments, the options to input user-specified melt and/or substrate material properties was added. The ability to perform invisicid and/or adiabatic spreading analysis was also added so that comparisons with analytical solutions and isothermal spreading tests could be carried out. In terms of refining the capability to carry out reactor material melt spreading analyses, the code was upgraded with a new melt viscosity model; the capability was added to treat situations in which solid fraction buildup between the liquidus-solidus is non-linear; and finally, the ability to treat an interfacial heat transfer resistance between the melt and substrate was incorporated. This last set of changes substantially improved the predictive capability of the code in terms of addressing reactor material melt spreading tests. Aside from improvements and upgrades, a method was developed to fit the model to the various melt spreading tests in a manner that allowed uncertainties in the model predictions to be statistically characterized. With these results, a sensitivity study was performed to investigate the assumption of uniform spreading in the EPR core catcher that addressed parametric variations in: (1) melt pour mass, (2) melt composition, (3) me

  17. ELECTRICAL CONDUCTIVITY OF A GRAPHITE BASED COMPOSITE AS AFFECTED BY THE DEGREE OF MIXEDNESS OF GRAPHITE IN

    E-Print Network [OSTI]

    filled polymers and the mechanisms involved in the formation of conductive composites of polymerELECTRICAL CONDUCTIVITY OF A GRAPHITE BASED COMPOSITE AS AFFECTED BY THE DEGREE OF MIXEDNESS of the volume conductivity of the composite. Background Electrically conductive nonmetallic materials are used

  18. Melt generation, crystallization, and extraction beneath segmented oceanic transform faults

    E-Print Network [OSTI]

    Gregg, Patricia M.

    We examine mantle melting, fractional crystallization, and melt extraction beneath fast slipping, segmented oceanic transform fault systems. Three-dimensional mantle flow and thermal structures are calculated using a ...

  19. Experimental studies of melting and crystallization processes in planetary interiors

    E-Print Network [OSTI]

    Krawczynski, Michael James

    2011-01-01T23:59:59.000Z

    Melting and crystallization processes on the Earth and Moon are explored in this thesis, and the topics of melt generation, transport, and crystallization are discussed in three distinct geologic environments: the Moon's ...

  20. Depleted uranium dioxide melting in cold crucible melter and production of granules from the melt for use in casks for spent nuclear fuel and radioactive wastes

    SciTech Connect (OSTI)

    Gotovchikov, Vitaly; Seredenko, V.A.; Shatalov, V.V.; Mironov, B.S.; Kaplenkov, V.N.; Seredenko, A.V.; Saranchin, V.K.; Shulgin, A.S.; Kalmakov, Danila [All-Russian Research Institute of Chemical Technology (ARRICT), Kashirskoe Shosse 33, Moscow 115230 (Russian Federation); Haire, M.J.; Forsberg, C.W. [Oak Ridge National Laboratory - ORNL, 1 Bethel Valley Rd, Oak Ridge, TN 37830 (United States)

    2007-07-01T23:59:59.000Z

    Available in abstract form only. Full text of publication follows: This paper describes the results of joint research program of Russian Research Institute of Chemical Technology and Oak Ridge National Laboratory to develop new materials for build spent nuclear fuel (SNF) storage, transport, and disposal casks using shielding made with depleted uranium dioxide (DUO{sub 2}) in a DUO{sub 2}-steel cermet or a DUCRETE with DUAGG (DUO{sub 2} aggregate) with selective additives in cement matrix. The preparation of DUO{sub 2} particles and aggregates for shielding could be produced from technologies that are extrapolated from the costly multi-step nuclear fuel pellet technologies. Melting the DUO{sub 2} and allowing it to freeze will produce a product near 100% theoretical density and assure that the product produces no volatile materials upon subsequent heating. Melting is a one step process that provides an opportunity to include additives in the DUO{sub 2} to modify its chemical or nuclear properties. The proposed work is directed to develop cold-wall induction heated melters (ICCM) for this specific application. Experiments on melting DUO{sub 2} were carried out in high frequency ICCM with cold crucible. It was experimentally proved an opportunity to produce molten DUO{sub 2} from mixed oxides (DU{sub 3}O{sub 8}) by reducing melting in ICCM. This will allow using DU{sub 3}O{sub 8} generated in direct conversion of depleted uranium hexafluoride as source material for melted and granulated DUO{sub 2} production. Experiments on the addition of alloying components - gadolinium oxide and others into DUO{sub 2} melt while in crucible to improve neutron and gamma radiation-shielding and operation properties of the final solids were carried out. (authors)

  1. An Investigation of the Effect of Graphite Degradation on the Irreversible Capacity in Lithium-ion Cells

    E-Print Network [OSTI]

    Hardwick, Laurence

    2008-01-01T23:59:59.000Z

    graphite anodes suffer severe surface structural damage upon prolonged cycling in rechargeable lithium-ion batteries.

  2. OECD MCCI project Melt Eruption Test (MET) design report, Rev. 2. April 15, 2003.

    SciTech Connect (OSTI)

    Farmer, M. T.; Lomperski, S.; Kilsdonk, D. J.; Aeschlimann, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)

    2011-05-23T23:59:59.000Z

    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. The Melt Coolability and Concrete Interaction (MCCI) program is pursuing separate effect tests to examine the viability of the melt coolability mechanisms identified as part of the MACE program. These mechanisms include bulk cooling, water ingression, volcanic eruptions, and crust breach. At the second PRG meeting held at ANL on 22-23 October 2002, a preliminary design1 for a separate effects test to investigate the melt eruption cooling mechanism was presented for PRG review. At this meeting, NUPEC made several recommendations on the experiment approach aimed at optimizing the chances of achieving a floating crust boundary condition in this test. The principal recommendation was to incorporate a mortar sidewall liner into the test design, since data from the COTELS experiment program indicates that corium does not form a strong mechanical bond with this material. Other recommendations included: (i) reduction of the electrode elevation to well below the melt upper surface elevation (since the crust may bond to these solid surfaces), and (ii) favorably taper the mortar liner to facilitate crust detachment and relocation during the experiment. Finally, as a precursor to implementing these modifications, the PRG recommended the development of a design for a small-scale scoping test intended to verify the ability of the mortar liner to preclude formation of an anchored bridge crust under core-concrete interaction conditions. This revised Melt Eruption Test (MET) plan is intended to satisfy these PRG recommendations. Specifically, the revised plan focuses on providing data on the extent of crust growth and melt eruptions as a function of gas sparging rate under well-controlled experiment conditions, including a floating crust boundary condition. The overall objective of MET is to determine to what extent core debris is rendered coolable by eruptive-type processes that breach the crust that rests upon the melt. The specific objectives of this test are as follows: (1) Evaluate the augmentation in surface heat flux during periods of melt eruption; (2) Evaluate the melt entrainment coefficient from the heat flux and gas flow rate data for input into models that calculate ex-vessel debris coolability; (3) Characterize the morphology and coolability of debris resulting from eruptive processes that transport melt into overlying water; and (4) Discriminate between periods when eruptions take the form of particle ejections into overlying water, leading to a porous particle bed, and single-phase extrusions, which lead to volcano-type structures.

  3. Hydrous silicate melt at high pressure Mainak Mookherjee1

    E-Print Network [OSTI]

    Stixrude, Lars

    LETTERS Hydrous silicate melt at high pressure Mainak Mookherjee1 , Lars Stixrude2 & Bijaya Karki3 The structure and physical properties of hydrous silicate melts and the solubility of water in melts over most in structure to our finding that the water­silicate system becomes increasingly ideal at high pressure: we find

  4. A Simple Thermodynamic Model for Melting of Peridotite in the System NCFMASOCr

    E-Print Network [OSTI]

    Jennings, Eleanor S.; Holland, Tim J. B.

    2015-05-25T23:59:59.000Z

    not included and melting was not considered. The consequences of adding Fe3þ and Cr to peridotites and their constituent phases is exam- ined here, particularly with respect to the effects on the spinel–garnet transition and on melting at depth. Addition of Fe3... þ and Cr in garnet is done via the end- members andradite (andr, Ca3Fe2Si3O12) and knorrin- gite (knor, Mg3Cr2Si3O12), both of which exist already in the dataset of Holland & Powell (2011). The mixing model for garnets is an extension of that used...

  5. Evaluation of replacement thread lubricants for red lead and graphite in mineral oil

    SciTech Connect (OSTI)

    Jungling, T.L.; Rauth, D.R.; Goldberg, D.

    1998-04-30T23:59:59.000Z

    Eight commercially available thread lubricants were evaluated to determine the best replacement for Red Lead and Graphite in Mineral Oil (RLGMO). The evaluation included coefficient of friction testing, high temperature anti-seizing testing, room temperature anti-galling testing, chemical analysis for detrimental impurities, corrosion testing, off-gas testing, and a review of health and environmental factors. The coefficient of friction testing covered a wide variety of factors including stud, nut, and washer materials, sizes, manufacturing methods, surface coatings, surface finishes, applied loads, run-in cycles, and relubrication. Only one lubricant, Dow Corning Molykote P37, met all the criteria established for a replacement lubricant. It has a coefficient of friction range similar to RLGMO. Therefore, it can be substituted directly for RLGMO without changing the currently specified fastener torque values for the sizes, materials and conditions evaluated. Other lubricants did not perform as well as Molykote P37 in one or more test or evaluation categories.

  6. Decontamination of metals by melt refinings/slagging: An annotated bibliography

    SciTech Connect (OSTI)

    Mizia, R.E. [ed.; Worcester, S.A.; Twidwell, L.G.; Paolini, D.J.; Weldon, T.A.

    1993-07-01T23:59:59.000Z

    As the number of nuclear installations undergoing decontamination and decommissioning (D&D) increases, current radioactive waste storage space is consumed and establishment of new waste storage areas becomes increasingly difficult, the problem of handling and storing radioactive scrap metal (RSM) gains increasing importance in the DOE Environmental Restoration and Waste Management Program. To alleviate present and future waste storage problems, Westinghouse Idaho Nuclear Company (WINCO) is managing a program for the recycling of RSM for beneficial use within the DOE complex. As part of that effort, Montana Tech has been awarded a contract to help optimize melting and refining technology for the recycling of stainless steel RSM. The scope of the Montana Tech program includes a literature survey, a decontaminating slag design study, small scale melting studies to determine optimum slag compositions for removal of radioactive contaminant surrogates, analysis of preferred melting techniques, and coordination of large scale melting demonstrations (100--500 lbs) to be conducted at selected facilities. The program will support recycling and decontaminating stainless steel RSM for use in waste canisters for Idaho Waste Immobilization Facility densified high level waste. This report is the result of the literature search conducted to establish a basis for experimental melt/slag program development.

  7. Lattice model of linear telechelic polymer melts. II. Influence of chain stiffness on basic thermodynamic properties

    E-Print Network [OSTI]

    Wen-Sheng Xu; Karl F. Freed

    2015-06-26T23:59:59.000Z

    The lattice cluster theory (LCT) for semiflexible linear telechelic melts, developed in paper I, is applied to examine the influence of chain stiffness on the average degree of self-assembly and the basic thermodynamic properties of linear telechelic polymer melts. Our calculations imply that chain stiffness promotes self-assembly of linear telechelic polymer melts that assemble on cooling when either polymer volume fraction $\\phi$ or temperature $T$ is high, but opposes self-assembly when both $\\phi$ and $T$ are sufficiently low. This allows us to identify a boundary line in the $\\phi$-$T$ plane that separates two regions of qualitatively different influence of chain stiffness on self-assembly. The enthalpy and entropy of self-assembly are usually treated as adjustable parameters in classical Flory-Huggins type theories for the equilibrium self-assembly of polymers, but they are demonstrated here to strongly depend on chain stiffness. Moreover, illustrative calculations for the dependence of the entropy density of linear telechelic polymer melts on chain stiffness demonstrate the importance of including semiflexibility within the LCT when exploring the nature of glass formation in models of linear telechelic polymer melts.

  8. USING THE UTAH ENERGY BALANCE SNOW MELT MODEL TO QUANTIFY SNOW AND GLACIER MELT IN THE HIMALAYAN REGION

    E-Print Network [OSTI]

    Tarboton, David

    USING THE UTAH ENERGY BALANCE SNOW MELT MODEL TO QUANTIFY SNOW AND GLACIER MELT IN THE HIMALAYAN on a distributed version of the Utah Energy Balance (UEB) snowmelt model, referred to as UEBGrid, which was adapted: glacier and snow melt, Energy balance, model, remote sensing) INTRODUCTION Countries in Hindu Kush

  9. Systematic prediction of high-pressure melting curves of transition metals

    SciTech Connect (OSTI)

    Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)

    2014-10-28T23:59:59.000Z

    The pressure effects on melting temperatures of transition metals have been studied based on the combination of the modified Lindemann criterion with statistical moment method in quantum statistical mechanics. Numerical calculations have been performed for five transition metals including Cu, Pd, Pt, Ni, and Mn up to pressure 100?GPa. Our results are in good and reasonable agreements with available experimental data. This approach gives us a relatively simple method for qualitatively calculating high-pressure melting temperature. Moreover, it can be used to verify future experimental and theoretical works. This research proposes the potential of the combination of statistical moment method and the modified Lindemann criterion on predicting high-pressure melting of materials.

  10. Evaluation of feeds for melt and dilute process using an analytical hierarchy process

    SciTech Connect (OSTI)

    Krupa, J.F.

    2000-03-22T23:59:59.000Z

    Westinghouse Savannah River Company was requested to evaluate whether nuclear materials other than aluminum-clad spent nuclear fuel should be considered for treatment to prepare them for disposal in the melt and dilute facility as part of the Treatment and Storage Facility currently projected for construction in the L-Reactor process area. The decision analysis process used to develop this analysis considered many variables and uncertainties, including repository requirements that are not yet finalized. The Analytical Hierarchy Process using a ratings methodology was used to rank potential feed candidates for disposition through the Melt and Dilute facility proposed for disposition of Savannah River Site aluminum-clad spent nuclear fuel. Because of the scoping nature of this analysis, the expert team convened for this purpose concentrated on technical feasibility and potential cost impacts associated with using melt and dilute versus the current disposition option. This report documents results of the decision analysis.

  11. On the preparation of TiAl alloy by direct reduction of the oxide mixtures in calcium chloride melt

    SciTech Connect (OSTI)

    Prabhat K. Tripathy; Derek J. Fray

    2011-11-01T23:59:59.000Z

    In recent years, TiAl-based intermetallic alloys are being increasingly considered for application in areas such as (i) automobile/transport sector (passenger cars, trucks and ships) (ii) aerospace industry (jet engines and High Speed Civil Transport propulsion system) and (iii) industrial gas turbines. These materials offer excellent (i) high temperature properties (at higher than 6000C) (ii) mechanical strength and (iii) resistance to corrosion and as a result have raised renewed interest. The combination of these properties make them possible replacement materials for traditional nickel-based super-alloys, which are nearly as twice as dense (than TiAl based alloys). Since the microstructures of these intermetallic alloys affect, to a significant extent, their ultimate performance, further improvements (by way of alteration/modification of these microstructures), have been the subject matter of intense research investigations. It has now been established that the presence of alloy additives, such as niobium, tantalum, manganese, boron, chromium, silicon, nickel and yttrium etc, in specific quantities, impart marked improvement to the properties, viz. fatigue strength, fracture toughness, oxidation resistance and room temperature ductility, of these alloys. From a number of possible alloy compositions, {gamma}-TiAl and Ti-Al-Nb-Cr have, of late, emerged as two promising engineering alloys/materials. . The conventional fabrication process of these alloys include steps such as melting, forging and heat treatment/annealing of the alloy compositions. However, an electrochemical process offers an attractive proposition to prepare these alloys, directly from the mixture of the respective oxides, in just one step. The experimental approach, in this new process, was, therefore, to try to electrochemically reduce the (mixed) oxide pellet to an alloy phase. The removal of oxygen, from the (mixed) oxide pellet, was effected by polarizing the oxide pellet against a graphite electrode in a pool of molten calcium chloride at a temperature of 9000C. The dominant mechanism of the oxygen removal was the ionization of oxygen followed by its subsequent discharge, as CO2/CO, at the anode surface. The removal of oxygen from the oxide mixture helped form the alloy in situ. The presentation shall cover the detailed experimental results pertaining to the preparation, evaluation and characterization of Ti-47Al-2Nb-2Cr (atom%) alloy.

  12. Regelation: why does ice melt under pressure?

    E-Print Network [OSTI]

    Chang Q Sun

    2015-01-28T23:59:59.000Z

    Unlike other unusual materials whose bonds contract under compression, the O:H nonbond undergoes contraction and the H-O bond elongation towards O:H and H-O length symmetry in water and ice. The energy drop of the H-O bond dictates the melting point Tm depression of ice. Once the pressure is relieved, the O:H-O bond fully recovers its initial state, resulting in Regelation.

  13. Regelation: why does ice melt under pressure?

    E-Print Network [OSTI]

    Sun, Chang Q

    2015-01-01T23:59:59.000Z

    Unlike other unusual materials whose bonds contract under compression, the O:H nonbond undergoes contraction and the H-O bond elongation towards O:H and H-O length symmetry in water and ice. The energy drop of the H-O bond dictates the melting point Tm depression of ice. Once the pressure is relieved, the O:H-O bond fully recovers its initial state, resulting in Regelation.

  14. Blow molding of melt processible rubber

    SciTech Connect (OSTI)

    Abell, W.R.; Stuart, R.E.; Myrick, R.E.

    1991-07-01T23:59:59.000Z

    This article discusses the advantages of making hollow rubber parts by blow molding thermoplastic elastomers (TPEs) versus conventional rubber processing. It describes the various types of blow molding processes and it provides some insight into the rheological properties of melt processible rubber (MPR) and how MPR should be molded by each of these processes. A number of blow molded applications for MPR are also discussed.

  15. B{sub 4}C-SiC reaction-sintered coatings on graphite plasma facing components

    SciTech Connect (OSTI)

    Valentine, P.G.; Trester, P.W. [General Atomics, San Diego, CA (United States); Winter, J. [Kernforschungsanlage Juelich GmbH (Germany)] [and others

    1994-05-01T23:59:59.000Z

    Boron carbide plus silicon carbide (B{sub 4}C-SiC) reaction-sintered coatings for use on graphite plasma-facing components were developed. Such coatings are of interest in TEXTOR tokamak limiter-plasma interactions as a means of reducing carbon erosion, of providing a preferred release of boron for oxygen gettering, and of investigating silicon`s effect on radiative edge phenomena. Specimens evaluated had (a) either Ringsdorfwerke EK 98 graphite or Le Carbon Lorraine felt-type AEROLOR A05 CFC substrates; (b) multiphase coatings, comprised of B{sub 4}C, Sic, and graphite; (c) nominal coating compositions of 69 wt.-% B{sub 4}C + 31 wt.-% SiC; and (d) nominal coating thicknesses between 250 and 775 {mu}m. Coated coupons were evaluated by high heat flux experiments in the JUDITH (electron beam) test facility at KFA. Simulated disruptions, with energy densities up to 10 MJm{sup {minus}2}, and normal operation simulations, with power densities up to 12 MWm{sup {minus}2}, were conducted. The coatings remained adherent; at the highest levels tested, minor changes occurred, including localized remelting, modification of the crystallographic phases, occasional microcracking, and erosion.

  16. Topological Constraints in Directed Polymer Melts

    E-Print Network [OSTI]

    Serna, Pablo; Nahum, Adam

    2015-01-01T23:59:59.000Z

    Polymers in a melt may be subject to topological constraints, as in the example of unlinked polymer rings. How to do statistical mechanics in the presence of such constraints remains a fundamental open problem. We study the effect of topological constraints on a melt of directed polymers using simulations of a simple quasi-2D model. We find that fixing the global topology of the melt to be trivial changes the polymer conformations drastically. Polymers of length $L$ wander in the transverse direction only by a distance of order $(\\ln L)^\\zeta$ with $\\zeta \\simeq 1.5$. This is strongly suppressed in comparison with the Brownian scaling $L^{1/2}$ which holds in the absence of the topological constraint. It is also much less than the prediction $L^{1/4}$ of a mean-field-like `array of obstacles' model: thus we rule out such a model in the present setting. Dynamics are also strongly affected by the constraints, and a tagged monomer in an infinite system performs logarithmically slow subdiffusion. To cast light on...

  17. Low cation coordination in oxide melts

    SciTech Connect (OSTI)

    Skinner, Lawrie [State University of New York, Stony Brook] [State University of New York, Stony Brook; Benmore, Chris J [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Du, Jincheng [University of North Texas] [University of North Texas; Weber, Richard [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Neuefeind, Joerg C [ORNL] [ORNL; Tumber, Sonia [Materials Development, Inc., Evanston, IL] [Materials Development, Inc., Evanston, IL; Parise, John B [Stony Brook University (SUNY)] [Stony Brook University (SUNY)

    2014-01-01T23:59:59.000Z

    The complete set of Faber-Ziman partial pair distribution functions for a rare earth oxide liquid were measured for the first time by combining aerodynamic levitation, neutron diffraction, high energy x-ray diffraction and isomorphic substitution using Y2 O3 and Ho2 O3 melts. The average Y- O coordination is measured to be 5.5(2), which is significantly less than the octahedral coordination of crystalline Y2 O3 (or Ho2 O3 ). Investigation of high temperature La2 O3 , ZrO2 , SiO2 , and Al2 O3 melts by x-ray diffraction and molecular dynamics simulations also show lower-than-crystal cation- oxygen coordination. These measurements suggest a general trend towards lower M-O coordination compared to their crystalline counterparts. It is found that this coordination number drop is larger for lower field strength, larger radius cations and is negligible for high field strength (network forming) cations. These findings have broad implications for predicting the local structure and related physical properties of metal-oxide melts and oxide glasses.

  18. Local diamagnetic susceptibility of quasi-two-dimensional graphite

    SciTech Connect (OSTI)

    Nikolaev, E. G., E-mail: nikolaev@kapitza.ras.ru [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation); Kotosonov, A. S. [OAO NIIgrafit (Russian Federation)] [OAO NIIgrafit (Russian Federation); Shalashugina, E. A.; Troyanovskii, A. M. [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation)] [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation); Tsebro, V. I. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2013-08-15T23:59:59.000Z

    A sample of quasi-two-dimensional graphite (QTDG) whose magnetic properties are described within the Dirac fermion model is investigated by the nuclear magnetic resonance (NMR) and scanning tunneling microscopy (STM) techniques. The broad spectrum of the sample points to a large dispersion of crystallite sizes in this system, which is also confirmed by STM data. It is established that the local diamagnetic susceptibility may substantially exceed the average value over the sample and reaches an abnormally high value of -1.3 Multiplication-Sign 10{sup -4} emu/g at T = 4.2 K, which is greater than the corresponding value of highly oriented graphite by a factor of four.

  19. Catalytic graphitization of carbon aerogels by transition metals

    SciTech Connect (OSTI)

    Maldonado-Hodar, F.J.; Moreno-Castilla, C.; Rivera-Utrilla, J.; Hanzawa, Y.; Yamada, Y.

    2000-05-02T23:59:59.000Z

    Carbon aerogels and Cr-, Fe-, Co-, and Ni-containing carbon aerogels were obtained by pyrolysis, at temperatures between 500 and 1,800 C, of the corresponding aerogels prepared by the sol-gel method from polymerization of resorcinol with formaldehyde. All samples were characterized by mercury porosimetry, nitrogen adsorption, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. Results obtained show that carbon aerogels are, essentially, macroporous materials that maintain large pore volumes even after pyrolysis at 1,800 C. For pyrolysis at temperatures higher than 1,000 C, the presence of the transition metals produced graphitized areas with three-dimensional stacking order, as shown by HRTEM, XRD, and Raman spectroscopy. HRTEM also showed that the metal-carbon containing aerogels were formed by polyhedral structures. Cr and Fe seem to be the best catalysts for graphitization of carbon aerogels.

  20. Testing of Small Graphite Samples for Nuclear Qualification

    SciTech Connect (OSTI)

    Julie Chapman

    2010-11-01T23:59:59.000Z

    Accurately determining the mechanical properties of small irradiated samples is crucial to predicting the behavior of the overal irradiated graphite components within a Very High Temperature Reactor. The sample size allowed in a material test reactor, however, is limited, and this poses some difficulties with respect to mechanical testing. In the case of graphite with a larger grain size, a small sample may exhibit characteristics not representative of the bulk material, leading to inaccuracies in the data. A study to determine a potential size effect on the tensile strength was pursued under the Next Generation Nuclear Plant program. It focuses first on optimizing the tensile testing procedure identified in the American Society for Testing and Materials (ASTM) Standard C 781-08. Once the testing procedure was verified, a size effect was assessed by gradually reducing the diameter of the specimens. By monitoring the material response, a size effect was successfully identified.

  1. Shallow melt apparatus for semicontinuous czochralski crystal growth

    DOE Patents [OSTI]

    Wang, Tihu; Ciszek, Theodore F.

    2006-01-10T23:59:59.000Z

    In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt crucible (20) to eliminate the necessity supplying a large quantity of feed stock materials that had to be preloaded in a deep crucible to grow a large ingot, comprising a gas tight container a crucible with a deepened periphery (25) to prevent snapping of a shallow melt and reduce turbulent melt convection; source supply means for adding source material to the semiconductor melt; a double barrier (23) to minimize heat transfer between the deepened periphery (25) and the shallow melt in the growth compartment; offset holes (24) in the double barrier (23) to increase melt travel length between the deepened periphery (25) and the shallow growth compartment; and the interface heater/heat sink (22) to control the interface shape and crystal growth rate.

  2. Graphite having improved thermal stress resistance and method of preparation

    DOE Patents [OSTI]

    Kennedy, Charles R. (Oak Ridge, TN)

    1980-01-01T23:59:59.000Z

    An improved method for fabricating a graphite article comprises the steps of impregnating a coke article by first heating the coke article in contact with a thermoplastic pitch at a temperature within the range of 250.degree.-300.degree. C. at a pressure within the range of 200-2000 psig for at least 4-10 hours and then heating said article at a temperature within the range of 450.degree.-485.degree. C. at a pressure of 200-2000 psig for about 16-24 hours to provide an impregnated article; heating the impregnated article for sufficient time to carbonize the impregnant to provide a second coke article, and graphitizing the second coke article. A graphite having improved thermal stress resistance results when the coke to be impregnated contains 1-3 wt.% sulfur and no added puffing inhibitors. An additional improvement in thermal stress resistance is achieved when the second coke article is heated above about 1400.degree. C. at a rate of at least 10.degree. C./minute to a temperature above the puffing temperature.

  3. Laser-excited atomic fluorescence of atoms produced in a graphite furnace

    SciTech Connect (OSTI)

    Goforth, D.; Winefordner, J.D.

    1986-11-01T23:59:59.000Z

    Laser-excited atomic fluorescence in a graphite furnace gives detection limits for Pb, Cu, Mn, Sn, Al, In, Li, and Pt, in the picogram to sub-picogram range. The linear dynamic range for these elements varies from 3 to 7 orders of magnitude. A graphite rod, a plain graphite cup, and a slotted graphite cup are compared as the cuvette in the fluorescence system. Detection limits for a pyrolytic coating, a tantalum foil liner, and a tantalum carbide coating of the graphite cuvette are compared. A hydrogen-argon atmosphere, a low-pressure atmosphere, and an argon atmosphere are compared as the atmosphere surrounding the graphite cuvette. Lastly, Cu and Mn are determined in several standard reference materials.

  4. Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

    DOE Patents [OSTI]

    Makowiecki, D.M.; Ramsey, P.B.; Juntz, R.S.

    1995-07-04T23:59:59.000Z

    An improved method is disclosed for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite`s high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding. 11 figs.

  5. Understanding Creep Mechanisms in Graphite with Experiments, Multiscale Simulations, and Modeling

    SciTech Connect (OSTI)

    Eapen, Jacob; Murty, Korukonda; Burchell, Timothy

    2014-06-02T23:59:59.000Z

    Disordering mechanisms in graphite have a long history with conflicting viewpoints. Using Raman and x-ray photon spectroscopy, electron microscopy, x-ray diffraction experiments and atomistic modeling and simulations, the current project has developed a fundamental understanding of early-to-late state radiation damage mechanisms in nuclear reactor grade graphite (NBG-18 and PCEA). We show that the topological defects in graphite play an important role under neutron and ion irradiation.

  6. Laser-induced dehydration of graphite oxide coatings on polymer substrates

    SciTech Connect (OSTI)

    Longo, Angela, E-mail: angela.longo@cnr.it; Palomba, Mariano; Carotenuto, Gianfranco; Nicolais, Luigi [Institute for Composite and Biomedical Materials, National Research Council, Viale Kennedy, 54, Mostra d'Oltremare Padiglione 20, 80125 Napoli (Italy); Orabona, Emanuele; Maddalena, Pasqualino [Department of Physics, University of Naples, Federico II, via cintia, 80126, Naples, Italy and SPIN Institute, National Research Council, UOS Naples, via cintia, 80126, Naples (Italy); Ambrosio, Antonio [SPIN Institute, National Research Council, UOS Naples, via cintia, 80126, Naples (Italy)

    2014-05-15T23:59:59.000Z

    Nanosized graphite has been oxidized by the Hummers method to give high quality graphite oxide. This reaction is characterized by a very fast kinetic behavior and a high yield. The produced graphite oxide has been conveniently used to pattern graphene by using a standard photolithographic method, and the resulting systems have been characterized by optical microscopy (OM), scanning electron microscopy (SEM) and by Fourier transform infrared spectroscopy (FT-IR) and Visible-Near Infrared spectroscopy (Vis-NIR)

  7. advanced gas cooled graphite moderated reactor: Topics by E-print...

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

    temperatures during normal (more) Moore, Eugene James Thomas 2006-01-01 2 THORIUM FUEL CYCLES: A GRAPHITE-MODERATED MOLTEN SALT REACTOR Physics Websites Summary: ,...

  8. air-cooled graphite reactors: Topics by E-print Network

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

    an estimated 1,282 cubic yards of contaminated steel and filter elements from 4 THORIUM FUEL CYCLES: A GRAPHITE-MODERATED MOLTEN SALT REACTOR Physics Websites Summary: ,...

  9. Environmental and health effects review for obscurant graphite flakes. Final report, 1991 July--1993 May

    SciTech Connect (OSTI)

    Driver, C.J.; Ligotke, M.W.; Landis, W.G.; Downs, J.L.; Tiller, B.L.; Moore, E.B. Jr.; Cataldo, D.A.

    1993-07-01T23:59:59.000Z

    The health and environmental effects of obscurant graphite flakes were reviewed and compared to predicted levels of graphite flake material in the field during typical testing and training scenarios. Graphite flake dispersion and deposition for simulated mechanical and pyrotechnic releases were determined using a modified Gaussian atmospheric plume-dispersion model. The potential for wind resuspension of graphite flakes is controlled by weathering processes and incorporation rates in soil. Chemically, graphite flakes pose little risk to aquatic or terrestrial systems. Mechanical damage to plants and invertebrate and vertebrate organisms from the flakes is also minimal. In humans, the pathological and physiological response to inhaled graphite flake is similar to that induced by nuisance dusts and cause only transient pulmonary changes. Repeated exposure to very high concentrations (such as those near the source generator) may overwhelm the clearance mechanisms of the lung and result in pulmonary damage from the retained particles in unprotected individuals. However, these lesions either resolve with time or are of limited severity. Health effects of mixed aerosols of mixed aerosols of graphite and fog oil are similar to those produced by graphite flakes alone. Environmental impacts of fog oil-coated graphite flakes are not well known.

  10. Melting a granular glass by cooling

    E-Print Network [OSTI]

    Jan Plagge; Claus Heussinger

    2013-02-05T23:59:59.000Z

    Driven granular systems readily form glassy phases at high particle volume fractions and low driving amplitudes. We use computer simulations of a driven granular glass to evidence a re-entrance melting transition into a fluid state, which, contrary to intuition, occurs by \\emph{reducing} the amplitude of the driving. This transition is accompanied by anomalous particle dynamics and super-diffusive behavior on intermediate time-scales. We highlight the special role played by frictional interactions, which help particles to escape their glassy cages. Such an effect is in striking contrast to what friction is expected to do: reduce particle mobility by making them stick.

  11. Reuse of steel and aluminium without melting

    E-Print Network [OSTI]

    Cooper, Daniel

    2014-01-07T23:59:59.000Z

    -of-life metal components that could be reused for each product, the catalogue formed the basis of a set of semi-structured interviews with industrial experts. The results suggest that approximately 30% of steel and aluminium used in current products could... Allwood J.M., Cullen J.M., Cooper D.R., Milford R.L., Patel A.C.H., Carruth M.A., McBrien M., 2010. Conserving our metal energy: avoiding melting steel and aluminium scrap to save energy and carbon. University of Cambridge, ISBN 978-0-903428-30-9 Allwood...

  12. Melting Instantons, Domain Walls, and Large N

    E-Print Network [OSTI]

    H. B. Thacker

    2008-10-22T23:59:59.000Z

    Monte Carlo studies of $CP^{N-1}$ sigma models have shown that the structure of topological charge in these models undergoes a sharp transition at $N=N_c\\approx 4$. For $NN_c$ it is dominated by extended, thin, 1-dimensionally coherent membranes of topological charge, which can be interpreted as domain walls between discrete quasi-stable vacua. These vacua differ by a unit of background electric flux. The transition can be identified as the delocalization of topological charge, or "instanton melting," a phenomenon first suggested by Witten to resolve the conflict between instantons and large $N$ behavior. Implications for $QCD$ are discussed.

  13. ARM - Lesson Plans: When Land Ice Melts

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow, AlaskaWhen Floating Ice Melts in the SeaWhen

  14. Microwave Melting | Y-12 National Security Complex

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTION A. Revised:7, at 3:00 pmYourMicrowave Melting

  15. Shallow Melt Apparatus for Semicontinuous Czochralski Crystal Growth

    DOE Patents [OSTI]

    Wang, T.; Ciszek, T. F.

    2006-01-10T23:59:59.000Z

    In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt crucible (20) to eliminate the necessity supplying a large quantity of feed stock materials that had to be preloaded in a deep crucible to grow a large ingot, comprising a gas tight container a crucible with a deepened periphery (25) to prevent snapping of a shallow melt and reduce turbulent melt convection; source supply means for adding source material to the semiconductor melt; a double barrier (23) to minimize heat transfer between the deepened periphery (25) and the shallow melt in the growth compartment; offset holes (24) in the double barrier (23) to increase melt travel length between the deepened periphery (25) and the shallow growth compartment; and the interface heater/heat sink (22) to control the interface shape and crystal growth rate.

  16. Retrograde Melting and Internal Liquid Gettering in Silicon

    SciTech Connect (OSTI)

    Hudelson, Steve; Newman, Bonna K.; Bernardis, Sarah; Fenning, David P.; Bertoni, Mariana I.; Marcus, Matthew A.; Fakra, Sirine C.; Lai, Barry; Buonassisi, Tonio

    2011-07-01T23:59:59.000Z

    Retrograde melting (melting upon cooling) is observed in silicon doped with 3d transition metals, via synchrotron-based temperature-dependent X-ray microprobe measurements. Liquid metal-silicon droplets formed via retrograde melting act as efficient sinks for metal impurities dissolved within the silicon matrix. Cooling results in decomposition of the homogeneous liquid phase into solid multiple-metal alloy precipitates. These phenomena represent a novel pathway for engineering impurities in semiconductor-based systems.

  17. Evolution of shear-induced melting in dusty plasma

    E-Print Network [OSTI]

    Yan Feng; J. Goree; Bin Liu

    2010-04-05T23:59:59.000Z

    The spatiotemporal development of melting is studied experimentally in a 2D dusty plasma suspension. Starting with an ordered lattice, and then suddenly applying localized shear, a pair of counter-propagating flow regions develop. A transition between two melting stages is observed before a steady state is reached. Melting spreads with a front that propagates at the transverse sound speed. Unexpectedly, coherent longitudinal waves are excited in the flow region.

  18. Electron beam skull melting and refining of secondary copper

    SciTech Connect (OSTI)

    Bychkov, Y.; Ladokhin, S. [Donetskvtortsvetmet, Donetsk (Ukraine)

    1995-12-31T23:59:59.000Z

    Electron Beam Melting is the most efficient technology for metals and alloys refining. For secondary metals processing the Electron Beam Skull Melting (EBSM) with the electromagnetic stirring (EMS) of melt in the crucible was shown to be the most appropriate. The copper produced by EBSM with EMS possesses higher density and electric conductivity in comparison with other refining methods. The details for high power electrical machines were cast of the copper waste refined by EBSM technology.

  19. Electron beam melting state-of-the-art 1984

    SciTech Connect (OSTI)

    Bakish, R.

    1984-06-01T23:59:59.000Z

    In 1984 electron beam melting and refining appear poised for an important new growth phase. The driving force for this phase is improved production economics made possible by technological advances. There is also a new and exciting growth application for electron beam melting: its use for surface properties beneficiation. This article is based in part on the content of the Conference on Electron Beam Melting and Refining, The State-of-the-Art 1983, held in November 1983 in Reno, Nevada.

  20. Molecular thermodynamics of polymer melts at interfaces

    SciTech Connect (OSTI)

    Theodorou, D.N.

    1988-09-01T23:59:59.000Z

    A lattice model is developed for the prediction of structure and thermodynamic properties at free polymer melt surfaces and polymer melt/solid interfaces. Density variations in the interfacial region are taken into account by introducing voids in the lattice, in the spirit of the equation of state theory of Sanchez and Lacombe. Intramolecular energy (chain stiffness) effects are explicitly incorporated. The model is derived through a rigorous statistical mechanical and thermodynamic analysis, which is based on the concept of availability. Two cases are considered: ''full equilibrium,'' whereby the interfacial polymer is taken as free to exchange heat, work and mass with a bulk polymer phase at given temperature and pressure; and ''restricted equilibrium,'' whereby a thin polymer film is allowed to equilibrate locally in response to ambient temperature and pressure, but in which chains do not necessarily have the same chemical potential as in the unconstrained bulk. Techniques are developed for calculating surface tension, adhesion tension, density profiles, chain shape, bond orientation, as well as the distribution of segments of various orders in the interfacial region. 28 refs., 6 figs.

  1. The influence of melting process and parameters on the structure and homogeneity of titanium-tantalum alloys

    SciTech Connect (OSTI)

    Dunn, P.S.; Korzewka, D.; Garcia, F. [Los Alamos National Lab., NM (United States); Damkroger, B.K.; Van Den Avyle, J.A.; Tissot, R.G. [Sandia National Labs., Albuquerque, NM (United States)

    1995-12-31T23:59:59.000Z

    Alloys of titanium with refractory metals are attractive materials for applications requiring high temperature strength and corrosion resistance. However, the widely different characteristics of the component elements have made it difficult to produce sound, compositionally homogeneous ingots using traditional melting techniques. This is particularly critical because the compositional ranges spanned by the micro- and macrosegregation in theses systems can easily encompass a number of microconstituents which are detrimental to mechanical properties. This paper presents results of a study of plasma (PAM) and vacuum-arc (VAR) melting of a 60 wt% tantalum, 40 wt% titanium binary alloy. The structural and compositional homogeneity of both PAM consolidated + PAM remelted, and PAM consolidated + VAR remelted ingots were characterized and compared using optical and electron microscopy and x-ray fluorescence microanalysis. Additionally, the effect of melting parameter, including melt rate and magnetic stirring, was studied. Results indicate that PAM remelting achieves more complete dissolution of lie starting electrode, due to greater local superheat, than does VAR remelting. PAM remelting also produces a finer as-solidified grain structure, due to the smaller molten pool and lower local solidification times. Conversely, VAR remelting produces an ingot with a more uniform macrostructure, due to the more stable movement of the solidification interface and more uniform material feed rate. Based on these results, a three-step process of PAM consolidation, followed by a PAM intermediate melt and a VAR final melt, has been selected for further development of the alloy and processing sequence.

  2. Enhanced performance of graphite anode materials by AlF3 coating for lithium-ion batteries

    SciTech Connect (OSTI)

    Ding, Fei; Xu, Wu; Choi, Daiwon; Wang, Wei; Li, Xiaolin; Engelhard, Mark H.; Chen, Xilin; Yang, Zhenguo; Zhang, Jiguang

    2012-04-27T23:59:59.000Z

    In order to form the stable surface film and to further enhance the long-term cycling stability of the graphite anodes of lithium-ion batteries, the surface of graphite powders has been modified by AlF3 coating through chemical precipitation method. The AlF3-coated graphite shows no evident changes in the bulk structure and a thin AlF3-coating layer of about 2 nm thick is found to uniformly cover the graphite particles with 2 wt% AlF3 content. However, it delivers a higher initial discharge capacity and largely improved rate performances compared to the pristine graphite. Remarkably, AlF3 coated graphite demonstrated a much better cycle life. After 300 cycles, AlF3 coated graphite and uncoated graphite show capacity retention of 92% and 81%, respectively. XPS measurement shows that a more conductive solid electrode interface (SEI) layer was formed on AlF3 coated graphite as compared to uncoated graphite. SEM monograph also reveals that the AlF3-coated graphite particles have a much more stable surface morphology after long-term cycling. Therefore, the improved electrochemical performance of AlF3 coated graphite can be attributed to a more stable and conductive SEI formed on coated graphite anode during cycling process.

  3. Plasma arc melting of titanium-tantalum alloys

    SciTech Connect (OSTI)

    Dunn, P.; Patterson, R.A. [Los Alamos National Lab., NM (United States); Haun, R. [Retech, Inc., Ukiah, CA (United States)

    1994-08-01T23:59:59.000Z

    Los Alamos has several applications for high temperature, oxidation and liquid-metal corrosion resistant materials. Further, materials property constraints are dictated by a requirement to maintain low density; e.g., less than the density of stainless steel. Liquid metal compatibility and density requirements have driven the research toward the Ti-Ta system with an upper bound of 60 wt% Ta-40 wt% Ti. Initial melting of these materials was performed in a small button arc melter with several hundred grams of material; however, ingot quantities were soon needed. But, refractory metal alloys whose constituents possess very dissimilar densities, melting temperatures and vapor pressures pose significant difficulty and require specialized melting practices. The Ti-Ta alloys fall into this category with the density of tantalum 16.5 g/cc and that of titanium 4.5 g/cc. Melting is further complicated by the high melting point of Ta(3020 C) and the relatively low boiling point of Ti(3287 C). Previous electron beam melting experience with these materials resulted, in extensive vaporization of the titanium and poor chemical homogeneity. Vacuum arc remelting(VAR) was considered as a melting candidate and discarded due to density and vapor pressure issues associated with electron beam. Plasma arc melting offered the ability to supply a cover gas to deal with vapor pressure issues as well as solidification control to help with macrosegregation in the melt and has successfully produced high quality ingots of the Ti-Ta alloys.

  4. Atomistic Study of the Melting Behavior of Single Crystalline...

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

    and 110-oriented lateral facets, respectively. Citation: Wang Z, X Zu, F Gao, and WJ Weber.2007."Atomistic Study of the Melting Behavior of Single Crystalline Wurtzite Gallium...

  5. Beam-induced graphitic carbon cage transformation from sumanene aggregates

    SciTech Connect (OSTI)

    Fujita, Jun-ichi, E-mail: fujita@bk.tsukuba.ac.jp; Tachi, Masashi; Murakami, Katsuhisa [Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573 (Japan); Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Tsukuba 305-8573 (Japan); Sakurai, Hidehiro; Morita, Yuki; Higashibayashi, Shuhei [Research Center of Integrative Molecular Systems, Institute for Molecular Science, Myodaiji, Okazaki 444-8787 (Japan); Takeguchi, Masaki [Transmission Electron Microscopy Station, National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    2014-01-27T23:59:59.000Z

    We found that electron-beam irradiation of sumanene aggregates strongly enhanced their transformation into a graphitic carbon cage, having a diameter of about 20?nm. The threshold electron dose was about 32 mC/cm{sup 2} at 200?keV, but the transformation is still induced at 20?keV. The transformation sequence suggested that the cage was constructed accompanied by the dynamical movement of the transiently linked sumanene molecules in order to pile up inside the shell. Thus, bond excitation in the sumanene molecules rather than a knock-on of carbon atoms seems to be the main cause of the cage transformation.

  6. Molecular Dynamics Simulation of Collisions between Hydrogen and Graphite

    E-Print Network [OSTI]

    A. Ito; H. Nakamura

    2006-04-26T23:59:59.000Z

    Hydrogen adsorption by graphite is examined by classical molecular dynamics simulation using a modified Brenner REBO potential. Such interactions are typical in chemical sputtering experiments, and knowledge of the fundamental behavior of hydrogen and graphene in collisional conditions is essential for modeling the sputtering mechanism. The hydrogen adsorption rate is found to be dependent on the incident hydrogen energy and not on graphene temperature. Rather than destroying the graphene, hydrogen incidence at energies of less than 100 eV can be classified into three regimes of adsorption, reflection and penetration through one or more graphene layers. Incidence at the lowest energies is shown to distort the graphene structure.

  7. An investigation of damage accumulation in graphite/epoxy laminates

    E-Print Network [OSTI]

    Norvell, Robert Gerald

    1985-01-01T23:59:59.000Z

    in Specimen A-4, [0/90?] , 98$ Ft s tu Crack Angle and Length Distribution in Specimen 8-5, [0/90, ] , 94$ s tu Crack Angle and Length Distribution in Specimen C-S, [0/90, ] , 91$ Ft . . ~ Crack Angle and Length Distribution in Specimen E-9, tO /90... August 1985 Major Subject: Aerospace Engineering AN INVESTIGATION OF DAMAGE ACCUMULATION IN GRAPHITE/EPOXY LAMINATES A Thesis by ROBERT GERALD NORVELL Approved as to style and content by: David H. Allen (Co-Chair of C mmitt. ) Richard A. Schap...

  8. Dynamic scanning probe microscopy of adsorbed molecules on graphite

    E-Print Network [OSTI]

    N. Berdunov; A. J. Pollard; P. H. Beton

    2009-01-08T23:59:59.000Z

    We have used a combined dynamic scanning tunneling and atomic force microscope to study the organisation of weakly bound adsorbed molecules on a graphite substrate. Specifically we have acquired images of islands of the perylene derivative molecules. These weakly bound molecules may be imaged in dynamic STM, in which the probe is oscillated above the surface. We show that molecular resolution may be readily attained and that a similar mode of imaging may be realised using conventional STM arrangement. We also show, using tunnelling spectroscopy, the presence of an energy gap for the adsorbed molecules confirming a weak molecule-substrate interaction.

  9. Method of fabricating silicon carbide coatings on graphite surfaces

    DOE Patents [OSTI]

    Varacalle, Jr., Dominic J. (Idaho Falls, ID); Herman, Herbert (Port Jefferson, NY); Burchell, Timothy D. (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    The vacuum plasma spray process produces well-bonded, dense, stress-free coatings for a variety of materials on a wide range of substrates. The process is used in many industries to provide for the excellent wear, corrosion resistance, and high temperature behavior of the fabricated coatings. In this application, silicon metal is deposited on graphite. This invention discloses the optimum processing parameters for as-sprayed coating qualities. The method also discloses the effect of thermal cycling on silicon samples in an inert helium atmosphere at about 1600.degree.C. which transforms the coating to silicon carbide.

  10. Optical and electronic properties of two dimensional graphitic silicon carbide

    E-Print Network [OSTI]

    Lin, Xiao; Lin, Shisheng; Hakro, Ayaz Ali; Cao, Te; Chen, Hongsheng; Zhang, Baile

    2012-01-01T23:59:59.000Z

    Optical and electronic properties of two dimensional few layers graphitic silicon carbide (GSiC), in particular monolayer and bilayer, are investigated by density functional theory and found different from that of graphene and silicene. Monolayer GSiC has direct bandgap while few layers exhibit indirect bandgap. The bandgap of monolayer GSiC can be tuned by an in-plane strain. Properties of bilayer GSiC are extremely sensitive to the interlayer distance. These predictions promise that monolayer GSiC could be a remarkable candidate for novel type of light-emitting diodes utilizing its unique optical properties distinct from graphene, silicene and few layers GSiC.

  11. Method of fabricating silicon carbide coatings on graphite surfaces

    DOE Patents [OSTI]

    Varacalle, D.J. Jr.; Herman, H.; Burchell, T.D.

    1994-07-26T23:59:59.000Z

    The vacuum plasma spray process produces well-bonded, dense, stress-free coatings for a variety of materials on a wide range of substrates. The process is used in many industries to provide for the excellent wear, corrosion resistance, and high temperature behavior of the fabricated coatings. In this application, silicon metal is deposited on graphite. This invention discloses the optimum processing parameters for as-sprayed coating qualities. The method also discloses the effect of thermal cycling on silicon samples in an inert helium atmosphere at about 1,600 C which transforms the coating to silicon carbide. 3 figs.

  12. Graphite and its Hidden Superconductivity | Stanford Synchrotron Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental AssessmentsGeoffrey(SC)Graphite Reactor 'In the early,

  13. Graphite and its Hidden Superconductivity | Stanford Synchrotron Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental AssessmentsGeoffrey(SC)Graphite Reactor 'In the

  14. Monash researchers led by Dr. Dan Li have developed a novel method for converting natural graphite into highly porous

    E-Print Network [OSTI]

    Albrecht, David

    natural graphite into highly porous graphene film for advanced applications. Figure 1: illustrates the conversion of inexpensive & abundant graphite into highly porous, mechanically robust conductive films (eg capacitors, batteries and fuel cells) n LCD displays and photovoltaic devices n Composites

  15. Redox reaction and foaming in nuclear waste glass melting

    SciTech Connect (OSTI)

    Ryan, J.L.

    1995-08-01T23:59:59.000Z

    This document was prepared by Pacific Northwest Laboratory (PNL) and is an attempt to analyze and estimate the effects of feed composition variables and reducing agent variables on the expected chemistry of reactions occurring in the cold cap and in the glass melt in the nuclear waste glass Slurry-fed, joule-heated melters as they might affect foaming during the glass-making process. Numerous redox reactions of waste glass components and potential feed additives, and the effects of other feed variables on these reactions are reviewed with regard to their potential effect on glass foaming. A major emphasis of this report is to examine the potential positive or negative aspects of adjusting feed with formic acid as opposed to other feed modification techniques including but not limited to use of other reducing agents. Feed modification techniques other than the use of reductants that should influence foaming behavior include control of glass melter feed pH through use of nitric acid. They also include partial replacement of sodium salts by lithium salts. This latter action (b) apparently lowers glass viscosity and raises surface tension. This replacement should decrease foaming by decreasing foam stability.

  16. Hydrogen storage material and process using graphite additive with metal-doped complex hydrides

    DOE Patents [OSTI]

    Zidan, Ragaiy (Aiken, SC); Ritter, James A. (Lexington, SC); Ebner, Armin D. (Lexington, SC); Wang, Jun (Columbia, SC); Holland, Charles E. (Cayce, SC)

    2008-06-10T23:59:59.000Z

    A hydrogen storage material having improved hydrogen absorbtion and desorption kinetics is provided by adding graphite to a complex hydride such as a metal-doped alanate, i.e., NaAlH.sub.4. The incorporation of graphite into the complex hydride significantly enhances the rate of hydrogen absorbtion and desorption and lowers the desorption temperature needed to release stored hydrogen.

  17. Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide

    E-Print Network [OSTI]

    for the preparation of graphene sheets from graphite. After numerous failed attempts to create graphene-based sheetsSynthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide Sasha of a colloidal suspension of exfoliated graphene oxide sheets in water with hydrazine hydrate results

  18. Adsorption of supramolecular building blocks on graphite: A force field and density functional theory study

    E-Print Network [OSTI]

    Pfeifer, Holger

    Adsorption of supramolecular building blocks on graphite: A force field and density functional-mail: axel.gross@uni-ulm.de The adsorption of the oligopyridine isomers 2,4'-BTP and 3,3'- BTP on graphite with an C6R-6-type dispersion correction, and the calculated adsorption energies are compared to the results

  19. Adsorption of the first layer of argon on graphite (*) Laboratoire des Composs non St0153chiomtriques,

    E-Print Network [OSTI]

    Boyer, Edmond

    L-9 Adsorption of the first layer of argon on graphite (*) F. Millot Laboratoire des Composés non déterminé des isothermes d'adsorption d'argon sur le graphite entre 55 et 62 K. Nous proposons une interprétation de nos résultats. Abstract. 2014 I have determined a set of adsorption isotherms for argon

  20. Relative stability of nanosized wurtzite and graphitic ZnO from density functional theory

    E-Print Network [OSTI]

    Melnik, Roderick

    Relative stability of nanosized wurtzite and graphitic ZnO from density functional theory Bin Wen to determine the relative stability of wurtzite and graphitic phases of ZnO nanostructures. Our results the threshold number, the relative stability of the wurtzite phase is observed. Finally, we discuss

  1. Effect of the graphite electrode material on the characteristics of molten salt electrolytically produced carbon nanomaterials

    SciTech Connect (OSTI)

    Kamali, Ali Reza, E-mail: ark42@cam.ac.uk; Schwandt, Carsten; Fray, Derek J.

    2011-10-15T23:59:59.000Z

    The electrochemical erosion of a graphite cathode during the electrolysis of molten lithium chloride salt may be used for the preparation of nano-structured carbon materials. It has been found that the structures and morphologies of these carbon nanomaterials are dependent on those of the graphite cathodes employed. A combination of tubular and spherical carbon nanostructures has been produced from a graphite with a microstructure of predominantly planar micro-sized grains and a minor fraction of more irregular nano-sized grains, whilst only spherical carbon nanostructures have been produced from a graphite with a microstructure of primarily nano-sized grains. Based on the experimental results, a best-fit regression equation is proposed that relates the crystalline domain size of the graphite reactants and the carbon products. The carbon nanomaterials prepared possess a fairly uniform mesoporosity with a sharp peak in pore size distribution at around 4 nm. The results are of crucial importance to the production of carbon nanomaterials by way of the molten salt electrolytic method. - Highlights: {yields} Carbon nanomaterials are synthesised by LiCl electrolysis with graphite electrodes. {yields} The degree of crystallinity of graphite reactant and carbon product are related. {yields} A graphite reactant is identified that enables the preparation of carbon nanotubes. {yields} The carbon products possess uniform mesoporosity with narrow pore size distribution.

  2. Direct Physical Exfoliation of Few-Layer Graphene from Graphite Grown on a Nickel Foil Using

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Direct Physical Exfoliation of Few-Layer Graphene from Graphite Grown on a Nickel Foil Using Physical graphene exfoliation from graphite using optimized PDMS PACS codes: 68.65.Pq, 81.05.ue, 81.05.uf for the site-specific direct physical exfoliation of few-layer graphene sheets from cheap and easily

  3. Simple Fabrication of a Highly Sensitive Glucose Biosensor Using Enzymes Immobilized in Exfoliated Graphite Nanoplatelets Nafion

    E-Print Network [OSTI]

    Lee, Ilsoon

    Simple Fabrication of a Highly Sensitive Glucose Biosensor Using Enzymes Immobilized in Exfoliated for the development of a glucose biosensor. Exfoliated graphite nanoplatelets (xGnP) were tested to enhance to 100s of dollars per gram) often makes them cost-prohibitive for some applications. Exfoliated graphite

  4. Study of polypyrrole graphite composite as anode material for secondary lithium-ion batteries

    E-Print Network [OSTI]

    Popov, Branko N.

    Study of polypyrrole graphite composite as anode material for secondary lithium-ion batteries of the composite. The composite material has been studied for specific discharge capacity, coulombic efficiency for the Li-ion battery. Of various carbon materials that have been tried, graphite is favored because it (i

  5. Emission characteristics and dynamics of C2 from laser produced graphite plasma

    E-Print Network [OSTI]

    Harilal, S. S.

    Emission characteristics and dynamics of C2 from laser produced graphite plasma S. S. Harilal, Riju 1996; accepted for publication 20 December 1996 The emission features of laser ablated graphite plume diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity

  6. Diffusion within a Layered, Graphite-Like, Spherical Electrode Theoretical Aspects

    E-Print Network [OSTI]

    Taylor, Philip L.

    Diffusion within a Layered, Graphite-Like, Spherical Electrode Theoretical Aspects Paul B. Antohi. Within this model, which mimics a layered, graphite-like spherical electrode, species can enter or leave further performance optimization of Li+ batteries have generated renewed interest into experimental

  7. Edge-Enriched Graphitic Anodes by KOH Activation for Higher Rate Capability Lithium Ion Batteries

    E-Print Network [OSTI]

    UG-36 Edge-Enriched Graphitic Anodes by KOH Activation for Higher Rate Capability Lithium Ion Batteries D. Zakhidov,1,2 R. Sugamata,3 T. Yasue,3 T. Hayashi,3 Y. A. Kim,3 and M. Endo4 1 for Exotic Nanocarbons (JST), Shinshu University, Nagano, Japan\\ Natural graphite is the most commercially

  8. Study of Sn-Coated Graphite as Anode Material for Secondary Lithium-Ion Batteries

    E-Print Network [OSTI]

    Popov, Branko N.

    Study of Sn-Coated Graphite as Anode Material for Secondary Lithium-Ion Batteries Basker Sandia National Laboratories, Albuquerque, New Mexico, USA Tin-graphite composites have been developed as an alternate anode material for Li-ion batteries using an autocatalytic deposition technique. The specific

  9. Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

    SciTech Connect (OSTI)

    Chang Ho Oh; Eung Soo Kim; Hee Cheon No; Nam Zin Cho

    2008-12-01T23:59:59.000Z

    The US Department of Energy is performing research and development (R&D) that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP) Program / GEN-IV Very High Temperature Reactor (VHTR). Phenomena identification and ranking studies (PIRT) to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Schultz et al., 2006). Consequently, the development of advanced air ingress-related models and verification and validation (V&V) are very high priority for the NGNP program. Following a loss of coolant and system depressurization, air will enter the core through the break. Air ingress leads to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heat-up of the bottom reflector and the reactor core and will cause the release of fission products eventually. The potential collapse of the bottom reflector because of burn-off and the release of CO lead to serious safety problems. For estimation of the proper safety margin we need experimental data and tools, including accurate multi-dimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model. We also need to develop effective strategies to mitigate the effects of oxidation. The results from this research will provide crucial inputs to the INL NGNP/VHTR Methods R&D project. This project is focused on (a) analytical and experimental study of air ingress caused by density-driven, stratified, countercurrent flow, (b) advanced graphite oxidation experiments, (c) experimental study of burn-off in the bottom reflector, (d) structural tests of the burnt-off bottom reflector, (e) implementation of advanced models developed during the previous tasks into the GAMMA code, (f) full air ingress and oxidation mitigation analyses, (g) development of core neutronic models, (h) coupling of the core neutronic and thermal hydraulic models, and (i) verification and validation of the coupled models.

  10. Benchmarking of Graphite Reflected Critical Assemblies of UO2

    SciTech Connect (OSTI)

    Margaret A. Marshall; John D. Bess

    2011-11-01T23:59:59.000Z

    A series of experiments were carried out in 1963 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for use in space reactor research programs. A core containing 93.2% enriched UO2 fuel rods was used in these experiments. The first part of the experimental series consisted of 253 tightly-packed fuel rods (1.27 cm triangular pitch) with graphite reflectors [1], the second part used 253 graphite-reflected fuel rods organized in a 1.506 cm triangular pitch [2], and the final part of the experimental series consisted of 253 beryllium-reflected fuel rods with a 1.506 cm triangular pitch. [3] Fission rate distribution and cadmium ratio measurements were taken for all three parts of the experimental series. Reactivity coefficient measurements were taken for various materials placed in the beryllium reflected core. The first part of this experimental series has been evaluated for inclusion in the International Reactor Physics Experiment Evaluation Project (IRPhEP) [4] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbooks, [5] and is discussed below. These experiments are of interest as benchmarks because they support the validation of compact reactor designs with similar characteristics to the design parameters for a space nuclear fission surface power systems. [6

  11. Generation of graphitic soot by an urban fire storm

    SciTech Connect (OSTI)

    Fields, D.E.; Cole, L.L.

    1987-01-01T23:59:59.000Z

    The authors have obtained samples of aerosols deposited during the Hiroshima fire storm that was initiated by the atomic bomb detonated on August 6, 1945. These particles, which we extracted from streaks of black rain found on a plaster wall, are being studied. Initial studies show that the artifact appears to contain aerosol particles that may be representative of the aerosols that may lead to a nuclear winter. Aerosol generation in urban fire storms have been considered by studying these particles. The presence of graphite as a component of these particles is suggested by electron photomicrographs and has been confirmed using Raman spectroscopy, surface ionization mass spectroscopy, and electron scattering for chemical analysis. Several hypotheses are being considered to explain the presence of this form of carbon. Among these are generation in sooty clouds, in raindrops, in the interior of the first storm, and on the wall surface itself. The distribution of particle sizes suggests that the residence time of particles in the atmosphere would be long if they were not removed by rainout. An experimental and theoretical examination of the conditions necessary to produce graphitic soot is in progress.

  12. Surface hardening of titanium alloys with melting depth controlled by heat sink

    DOE Patents [OSTI]

    Oden, Laurance L. (Albany, OR); Turner, Paul C. (Albany, OR)

    1995-01-01T23:59:59.000Z

    A process for forming a hard surface coating on titanium alloys includes providing a piece of material containing titanium having at least a portion of one surface to be hardened. The piece having a portion of a surface to be hardened is contacted on the backside by a suitable heat sink such that the melting depth of said surface to be hardened may be controlled. A hardening material is then deposited as a slurry. Alternate methods of deposition include flame, arc, or plasma spraying, electrodeposition, vapor deposition, or any other deposition method known by those skilled in the art. The surface to be hardened is then selectively melted to the desired depth, dependent on the desired coating thickness, such that a molten pool is formed of the piece surface and the deposited hardening material. Upon cooling a hardened surface is formed.

  13. Preliminary analysis of graphite dust releasing behavior in accident for HTR

    SciTech Connect (OSTI)

    Peng, W.; Yang, X. Y.; Yu, S. Y.; Wang, J. [Inst. of Nuclear and New Energy Technology, Tsinghua Univ., Beijing100084 (China)

    2012-07-01T23:59:59.000Z

    The behavior of the graphite dust is important to the safety of High Temperature Gas-cooled Reactors. This study investigated the flow of graphite dust in helium mainstream. The analysis of the stresses acting on the graphite dust indicated that gas drag played the absolute leading role. Based on the understanding of the importance of gas drag, an experimental system is set up for the research of dust releasing behavior in accident. Air driven by centrifugal fan is used as the working fluid instead of helium because helium is expensive, easy to leak which make it difficult to seal. The graphite particles, with the size distribution same as in HTR, are added to the experiment loop. The graphite dust releasing behavior at the loss-of-coolant accident will be investigated by a sonic nozzle. (authors)

  14. Low-melting point heat transfer fluid

    DOE Patents [OSTI]

    Cordaro, Joseph G. (Oakland, CA); Bradshaw, Robert W. (Livermore, CA)

    2011-04-12T23:59:59.000Z

    A low-melting point, heat transfer fluid comprising a mixture of LiNO.sub.3, NaNO.sub.3, KNO.sub.3, NaNO.sub.2 and KNO.sub.2 salts where the Li, Na and K cations are present in amounts of about 20-33.5 mol % Li, about 18.6-40 mol % Na, and about 40-50.3 mol % K and where the nitrate and nitrite anions are present in amounts of about 36-50 mol % NO.sub.3, and about 50-62.5 mol % NO.sub.2. These compositions can have liquidus temperatures between 70.degree. C. and 80.degree. C. for some compositions.

  15. Detection of Nonthermal Melting by Ultrafast X-ray

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    of super- heating of the interface but limited by the speed of sound. Typically, a layer a few tens, if a solid is heated to or above the melting temperature, nucleation of the liquid phase occurs around), which exceeds the melting temperature within several picoseconds. After nucleation of the liquid phase

  16. Electron beam melting and casting of zirconium and titanium alloys

    SciTech Connect (OSTI)

    Arzhakova, V.M.; Popov, E.I. [A.A. Bochvar All Union Scientific and Research Institute of Inorganic Materials, Moscow (Russian Federation); Dubrovski, V.A.; Frolov, V.I. [PO ChMZ, Glazov (Russian Federation); Ladohin, S.V.; Levitsky, N.I.; Chernyavsky, V.B. [Scientific and Research Institute of Casting, Kiev (Ukraine)

    1994-12-31T23:59:59.000Z

    The results of electron beam melting (EBM) and casting Zirconium and Titanium alloys are discussed. The data on different schedules used for EBM of this metals as well as equipment for crucible melting and special equipment for casting are described. The results of production of Zirconium and Titanium alloy mold castings for various purposes are presented.

  17. Electron beam melting and refining state of the art 1995

    SciTech Connect (OSTI)

    Bakish, R. [ed.

    1995-12-31T23:59:59.000Z

    This is the proceedings of the Electron Beam Melting and Refining - State of the Art 1995 Conference. It contains 23 of the 30 scheduled papers. Papers cover an array of electron beam melting applications, from industrial plating of metal strip, through government work on manufacturing and processing fissile alloys. Separate abstracts have been prepared for articles from this proceedings.

  18. ARTICLE IN PRESS Kinetics of convective crystal dissolution and melting,

    E-Print Network [OSTI]

    Zhang, Youxue

    Department of Geological Sciences, The University of Michigan, Ann Arbor, MI 48109-1063, USA5 Received 25 instability (similar to melting of ice) with or 14 without water (although presence of warm water may increase the dissociation rate). Dissociation of methane hydrate 15 into gas and water is similar to ice melting

  19. An analysis of variations in isentropic melt productivity

    E-Print Network [OSTI]

    Asimow, Paul D.

    An analysis of variations in isentropic melt productivity B y P. D. Asimow1 , M. M. Hirschmann1 productivity, cannot be determined directly from experiments and is commonly assumed to be constant on a ther- modynamic model of peridotite partial melting, we show that productivity for re- versible

  20. Electron-beam scull melting with electromagnetic stirring of melt in crucible

    SciTech Connect (OSTI)

    Ladokhin, S.V. [Institute for Casting Problems, Kiev (Ukraine)

    1994-12-31T23:59:59.000Z

    The technologies and equipment have been developed for electron-beam scull melting with electromagnetic stirring of melt for some Ni-based superalloys as well as for multi-component Ti-, Zr-, Nb-, and Mo-based alloys. Two types of scull crucible sets with electromagnetic stirring systems have been constructed, with the metal pouring by the crucible tilting or through the hole in the crucible bottom. In the second case slag does not fall into a mold, and the electron beam may be used for metal heating in the costing head, thus improving the quality of castings. The technologies developed allow to utilize scrap, cost part reverts, chips etc. thus saving virgin alloys. The electromagnetic stirring application permits to product multi-component alloys, to increase the mass of the metal poured, and to reduce the specific energy expenditure and metal loss through evaporation.

  1. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

    DOE Patents [OSTI]

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-04-08T23:59:59.000Z

    A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  2. Oxidation of PCEA nuclear graphite by low water concentrations in helium

    SciTech Connect (OSTI)

    Contescu, Cristian I [ORNL; Mee, Robert [University of Tennessee (UT); Wang, Peng [ORNL; Romanova, Anna V [University of Tennessee, Knoxville (UTK); Burchell, Timothy D [ORNL

    2014-10-01T23:59:59.000Z

    Accelerated oxidation tests were performed to determine kinetic parameters of the chronic oxidation reaction of PCEA graphite in contact with helium coolant containing low moisture concentrations in high temperature gas-cooled reactors. To the authors best knowledge such a study has not been done since the detailed analysis of reaction of H-451 graphite with steam [Velasquez, Hightower, Burnette, 1978]. Since that H-451 graphite is now unavailable, it is urgently needed to characterize chronic oxidation behavior of new graphite grades under qualification for gas-cooled reactors. The Langmuir-Hinshelwood mechanism of carbon oxidation by water results in a non-linear reaction rate expression, with at least six different parameters. They were determined in accelerated oxidation experiments that covered a large range of temperatures (800 to 1100 oC), and partial pressures of water (15 to 850 Pa) and hydrogen (30 to 150 Pa) and used graphite specimens thin enough (4 mm) in order to avoid diffusion effects. Data analysis employed a statistical method based on multiple likelihood estimation of parameters and simultaneous fitting of non-linear equations. The results show significant material-specific differences between graphite grades PCEA and H-451 which were attributed to microstructural dissimilarity of the two materials. It is concluded that kinetic data cannot be transferred from one graphite grade to another.

  3. Capacitance of edge plane of pyrolytic graphite in acetonitrile solutions

    SciTech Connect (OSTI)

    Minick, S.K.; Ishida, Takanobu

    1991-05-01T23:59:59.000Z

    The capacitance of the edge plane of pyrolytic graphite electrodes, in acetonitrile solutions, is measured by recording the current response to an applied triangular voltage sweep; TVS, and then fitting the current response with an appropriate function, (via a set of adjustable parameters). The pretreatment of the electrodes, the supporting electrolyte concentration used, and the frequency of the input TVS, were all found to affect the measured capacitance. In these experiments, a background current was also seen and the shape of the current output for the TVS; the charging/discharging curve, is shown to correlate with the magnitude of this background current. In addition, the size of the background current was found to have some dependence on the type of electrode pretreatment procedure used. 60 refs., 49 figs., 3 tabs.

  4. Countries Gasoline Prices Including Taxes

    Gasoline and Diesel Fuel Update (EIA)

    Selected Countries (U.S. dollars per gallon, including taxes) Date Belgium France Germany Italy Netherlands UK US 51115 6.15 6.08 6.28 6.83 6.96 6.75 3.06 5415 6.14 6.06...

  5. Sponsorship includes: Agriculture in the

    E-Print Network [OSTI]

    Nebraska-Lincoln, University of

    Sponsorship includes: · Agriculture in the Classroom · Douglas County Farm Bureau · Gifford Farm · University of Nebraska Agricultural Research and Development Center · University of Nebraska- Lincoln Awareness Coalition is to help youth, primarily from urban communities, become aware of agriculture

  6. Assessment of ceramic coatings for metal fuel melting crucible

    SciTech Connect (OSTI)

    Kim, Ki-Hwan; Song, Hoon; Kim, Jong-Hwan; Oh, Seok-Jin; Kim, Hyung-Tae; Lee, Chan-Bock [Korea Atomic Energy Research Institute, Yuseong, Daejeon 305-600 (Korea, Republic of)

    2013-07-01T23:59:59.000Z

    The objective of this study is to develop a coating method and material for crucibles to prevent material interactions with the U-Zr/U-TRU-Zr fuels during the manufacturing of SFR fuels. Refractory coatings were applied to niobium substrates by vacuum plasma-spray coating method. Melt dipping tests conducted were the coated rods lowered into the fuel melt at 1600 C. degrees, and withdrawn and cooled outside the crucible in the inert atmosphere of the induction furnace. Melt dipping tests of the coated Nb rods indicated that plasma-sprayed Y{sub 2}O{sub 3} coating doesn't form significant reaction layer between fuel melt and coating layer. Melt dipping tests of the coated Nb rods showed that TiC, TaC, and Y{sub 2}O{sub 3} coatings exhibited the promising performance among other ceramic coatings. These materials could be promising candidate materials for the reusable melt crucible of metal fuel for SFR. In addition, in order to develop the vacuum plasma-spray coating method for re-usable crucible of metal fuel slugs to be overcome the issue of thermal expansion mismatch between coating material and crucible, various combinations of coating conditions were investigated to find the bonding effect on the substrate in pursuit of more effective ways to withstand the thermal stresses. It is observed that most coating methods maintained sound coating state in U-Zr melt. (authors)

  7. Evolution of Shear-Induced Melting in a Dusty Plasma Yan Feng,* J. Goree, and Bin Liu

    E-Print Network [OSTI]

    Goree, John

    is reached. Melting spreads with a front that propagates at the transverse sound speed. Unexpectedly essentially on a 2D plane include a Wigner lattice of electrons on a liquid-He surface [8], ions confined to a crystalline solid or a liquid [17]. Coulomb repulsion is shielded with a screening length D [27]. Dusty

  8. Exploration of Melt Spinning as a Route to Large Volume Production...

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

    Exploration of Melt Spinning as a Route to Large Volume Production of Skutterudite Thermoelectric Materials Exploration of Melt Spinning as a Route to Large Volume Production of...

  9. 2013 American Geophysical Union. All Rights Reserved. High resolution imaging of the melt distribution in 1

    E-Print Network [OSTI]

    © 2013 American Geophysical Union. All Rights Reserved. High resolution imaging of the melt;© 2013 American Geophysical Union. All Rights Reserved. Abstract We determine the 3-D melt geometry

  10. Geek-Up: K East Reactor Demolition, Retrograde Melting and Cloud Pattern Tracking

    Broader source: Energy.gov [DOE]

    Recovery Act funds help clean up the Hanford site, retrograde melting (melting as something cools) and how open-cell clouds could help predict climate change.

  11. Graphite fuels combustion off-gas treatment options

    SciTech Connect (OSTI)

    Kirkham, R.J.; Lords, R.E.

    1993-03-01T23:59:59.000Z

    Scenarios for burning bulk graphite and for burning crushed fuel particles from graphite spent nuclear fuels have been considered. Particulates can be removed with sintered metal filters. Subsequent cooling would then condense semi-volatile fission products into or onto a particulate. These particulates would be trapped by a second sintered metal filter or downstream packed bed. A packed bed scrub column can be used to eliminate most of the iodine-129 and tritium. A molecular sieve bed is proposed to collect the residual {sup 129}I and other tramp radionuclides downstream (Ruthenium, etc.). Krypton-85 can be recovered, if need be, either by cryogenics or by the KALC process (Krypton Adsorption in Liquid Carbon dioxide). Likewise carbon-14 in the form of carbon dioxide could be collected with a caustic or lime scrub solution and incorporated into a grout. Sulfur dioxide present will be well below regulatory concern level of 4.0 tons per year and most of it would be removed by the scrubber. Carbon monoxide emissions will depend on the choice of burner and start-up conditions. Should the system exceed the regulatory concern level, a catalytic converter in the final packed bed will be provided. Radon and its daughters have sufficiently short half-lives (less than two minutes). If necessary, an additional holdup bed can be added before the final HEPA filters or additional volume can be added to the molecular sieve bed to limit radon emissions. The calculated total effective dose equivalent at the Idaho National Engineering Laboratory boundary from a single release of all the {sup 3}, {sup 14}C, {sup 85}Kr, and {sup 129}I in the total fuel mass if 0.43 mrem/year.

  12. Diffusion and Interdiffusion in Binary Metallic Melts

    E-Print Network [OSTI]

    P. Kuhn; J. Horbach; F. Kargl; A. Meyer; Th. Voigtmann

    2014-08-09T23:59:59.000Z

    We discuss the dependence of self- and interdiffusion coefficients on temperature and composition for two prototypical binary metallic melts, Al-Ni and Zr-Ni, in molecular-dynamics (MD) computer simulations and the mode-coupling theory of the glass transition (MCT). Dynamical processes that are mainly entropic in origin slow down mass transport (as expressed through self diffusion) in the mixture as compared to the ideal-mixing contribution. Interdiffusion of chemical species is a competition of slow kinetic modes with a strong thermodynamic driving force that is caused by non-entropic interactions. The combination of both dynamic and thermodynamic effects causes qualitative differences in the concentration dependence of self-diffusion and interdiffusion coefficients. At high temperatures, the thermodynamic enhancement of interdiffusion prevails, while at low temperatures, kinetic effects dominate the concentration dependence, rationalized within MCT as the approach to its ideal-glass transition temperature $T_c$. The Darken equation relating self- and interdiffusion qualitatively reproduces the concentration-dependence in both Zr-Ni and Al-Ni, but quantitatively, the kinetic contributions to interdiffusion can be slower than the lower bound suggested by the Darken equation. As temperature is decreased, the agreement with Darken's equation improves, due to a strong coupling of all kinetic modes that is a generic feature predicted by MCT.

  13. String melting in a photon bath

    SciTech Connect (OSTI)

    Karouby, Johanna, E-mail: karoubyj@mit.edu [Center for Theoretical Physics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachussetts 02139 (United States)

    2013-10-01T23:59:59.000Z

    We compute the decay rate of a metastable cosmic string in contact with a thermal bath by finding the instanton solution. The new feature is that this decay rate is found in the context of non thermal scalar fields in contact with a thermal bath of photons. In general, to make topologically unstable strings stable, one can couple them to such a bath. The resulting plasma effect creates metastable configurations which can decay from the false vacuum to the true vacuum. In our specific set-up, the instanton computation is realized for the case of two out-of-equilibrium complex scalar fields: one is charged and coupled to the photon field, and the other is neutral. New effects coming from the thermal bath of photons make the radius of the nucleated bubble and most of the relevant physical quantities temperature-dependent. However, the temperature appears in a different way than in the purely thermal case, where all scalar fields are in thermal equilibrium. As a result of the tunneling, the core of the initial string melts while bubbles of true vacuum expand at the speed of light.

  14. High density-high purity graphite prepared by hot isostatic pressing in refractory metal containers

    DOE Patents [OSTI]

    Hoenig, C.L.

    1994-08-09T23:59:59.000Z

    Porous graphite in solid form is hot isostatically pressed in a refractory metal container to produce a solid graphite monolith with a bulk density greater than or equal to 2.10 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed, chemically vapor deposited, or coated by some other suitable means onto graphite. Hot isostatic pressing at 2,200 C and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. Complex shapes can be made. 1 fig.

  15. High density-high purity graphite prepared by hot isostatic pressing in refractory metal containers

    DOE Patents [OSTI]

    Hoenig, Clarence L. (Livermore, CA)

    1994-01-01T23:59:59.000Z

    Porous graphite in solid form is hot isostatically pressed in a refractory metal container to produce a solid graphite monolith with a bulk density greater than or equal to 2.10 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed, chemically vapor deposited, or coated by some other suitable means onto graphite. Hot isostatic pressing at 2200.degree. C. and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. Complex shapes can be made.

  16. Graphite-ceramic rf Faraday-thermal shield and plasma limiter

    DOE Patents [OSTI]

    Hwang, D.L.Q.; Hosea, J.C.

    1983-05-05T23:59:59.000Z

    The present invention is directed to a brazing procedure for joining a ceramic or glass material (e.g., Al/sub 2/O/sub 3/ or Macor) to graphite. In particular, the present invention is directed to a novel brazing procedure for the production of a brazed ceramic graphite product useful as a Faraday shield. The brazed ceramic graphite Faraday shield of the present invention may be used in Magnetic Fusion Devices (e.g., Princeton Large Torus Tokamak) or other high temperature resistant apparatus.

  17. Method for synthesizing extremely high-temperature melting materials

    DOE Patents [OSTI]

    Saboungi, Marie-Louise (Chicago, IL); Glorieux, Benoit (Perpignan, FR)

    2007-11-06T23:59:59.000Z

    The invention relates to a method of synthesizing high-temperature melting materials. More specifically the invention relates to a containerless method of synthesizing very high temperature melting materials such as carbides and transition-metal, lanthanide and actinide oxides, using an aerodynamic levitator and a laser. The object of the invention is to provide a method for synthesizing extremely high-temperature melting materials that are otherwise difficult to produce, without the use of containers, allowing the manipulation of the phase (amorphous/crystalline/metastable) and permitting changes of the environment such as different gaseous compositions.

  18. Method For Synthesizing Extremely High-Temperature Melting Materials

    DOE Patents [OSTI]

    Saboungi, Marie-Louise (Chicago, IL); Glorieux, Benoit (Perpignan, FR)

    2005-11-22T23:59:59.000Z

    The invention relates to a method of synthesizing high-temperature melting materials. More specifically the invention relates to a containerless method of synthesizing very high temperature melting materials such as borides, carbides and transition-metal, lanthanide and actinide oxides, using an Aerodynamic Levitator and a laser. The object of the invention is to provide a method for synthesizing extremely high-temperature melting materials that are otherwise difficult to produce, without the use of containers, allowing the manipulation of the phase (amorphous/crystalline/metastable) and permitting changes of the environment such as different gaseous compositions.

  19. Energy Efficient Glass Melting - The Next Generation Melter

    SciTech Connect (OSTI)

    David Rue

    2008-03-01T23:59:59.000Z

    The objective of this project is to demonstrate a high intensity glass melter, based on the submerged combustion melting technology. This melter will serve as the melting and homogenization section of a segmented, lower-capital cost, energy-efficient Next Generation Glass Melting System (NGMS). After this project, the melter will be ready to move toward commercial trials for some glasses needing little refining (fiberglass, etc.). For other glasses, a second project Phase or glass industry research is anticipated to develop the fining stage of the NGMS process.

  20. Dissolution retardation of solid silica during glass batch-melting

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Marcial, Jose

    2011-07-15T23:59:59.000Z

    During glass-batch melting, solid silica (quartz) usually dissolves last. A retardation function was defined as a measure of the progressive inhibition of silica dissolution that occurs during batch melting. This function is based on the comparison of the measured rate of dissolution of silica particles with the hypothetical diffusion-controlled volume flux from regularly distributed particles with uniform concentration layers around them. The severe inhibition of silica dissolution has been attributed to the irregular spatial distribution of silica particles that is associated with the formation of nearly saturated melt at a portion of their surfaces. Irregular shapes and unequal sizes of particles also contribute to their extended lifetime.

  1. Melt-band instabilities with two-phase damage

    E-Print Network [OSTI]

    Rudge, John F.; Bercovici, David

    2015-03-09T23:59:59.000Z

    . Petrol., 151, 101–111. Holtzman, B.K., Groebner, N.J., Zimmerman, M.E., Ginsberg, S. & Kohlst- edt, D., 2003. Stress-driven melt segregation in partially molten rocks, Geochem. Geophys. Geosyst., 4, 8607, doi:10.1029/2001GC000258. Karato, S., 1989. Grain... olivine-rich rocks deformed in torsion, J. Petrol., 51, 21–42. Kohlstedt, D.L. & Holtzman, B.K., 2009. Shearing melt out of the Earth: an experimentalist’s perspective on the influence of deformation on melt extraction, Ann. Rev. Earth planet. Sci., 37...

  2. Method for Synthesizing Extremeley High Temperature Melting Materials

    DOE Patents [OSTI]

    Saboungi, Marie-Louise and Glorieux, Benoit

    2005-11-22T23:59:59.000Z

    The invention relates to a method of synthesizing high-temperature melting materials. More specifically the invention relates to a containerless method of synthesizing very high temperature melting materials such as borides, carbides and transition-metal, lanthanide and actinide oxides, using an Aerodynamic Levitator and a laser. The object of the invention is to provide a method for synthesizing extremely high-temperature melting materials that are otherwise difficult to produce, without the use of containers, allowing the manipulation of the phase (amorphous/crystalline/metastable) and permitting changes of the environment such as different gaseous compositions.

  3. Proceedings of the conference on electron beam melting and refining - state of the art 1994

    SciTech Connect (OSTI)

    Bakish, R. [ed.

    1994-12-31T23:59:59.000Z

    The volume: Proceedings of the Conference on Electron Beam Melting and Refining-State of the Art 1994 covers many aspects of electron beam production, process control, components, and applications. Included were several papers from the defunct Soviet Bloc nations concerning the specifications and uses for their electron beam furnaces. Main topics of the conference were: Electron Beam (EB) Equipment; Safety and Analytical Aspects related to EB Melting; Material Processing with EB; Other Applications for EB; and A Look at EB in the East. EB has many uses, several papers mentioned the recycling of uranium scrap, the casting of heat resistant or corrosion resistant alloys, or the improved microstructure of alloys with the technique.

  4. Melt-castable energetic compounds comprising oxadiazoles and methods of production thereof

    DOE Patents [OSTI]

    Pagoria, Philip F; Zhang, Mao X

    2013-11-12T23:59:59.000Z

    In one embodiment, a melt-castable energetic material comprises at least one of: 3,5-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazole (DNFO), and 3-(4-amino-1,2,5-oxadiazol-3-yl)-5-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2- ,4-oxadiazole (ANFO). In another embodiment, a method for forming a melt-castable energetic material includes reacting 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazole (DAFO) with oxygen or an oxygen-containing compound to form a mixture of at least: DNFO, and ANFO.

  5. Simulation of the temperature distribution in the selective beam melting process for polymer material

    SciTech Connect (OSTI)

    Riedlbauer, D., E-mail: daniel.riedlbauer@ltm.uni-erlangen.de, E-mail: julia.mergheim@ltm.uni-erlangen.de, E-mail: paul.steinmann@ltm.uni-erlangen.de; Mergheim, J., E-mail: daniel.riedlbauer@ltm.uni-erlangen.de, E-mail: julia.mergheim@ltm.uni-erlangen.de, E-mail: paul.steinmann@ltm.uni-erlangen.de; Steinmann, P., E-mail: daniel.riedlbauer@ltm.uni-erlangen.de, E-mail: julia.mergheim@ltm.uni-erlangen.de, E-mail: paul.steinmann@ltm.uni-erlangen.de [Chair of Applied Mechanics, Friedrich-Alexander-Universität Erlangen-Nürnberg (Germany)

    2014-05-15T23:59:59.000Z

    In the present contribution the temperature distribution in the selective beam melting process for polymer materials is simulated to better understand the influence of process parameters on the properties of the produced part. The basis for the developed simulation tool is the nonlinear heat equation including temperature dependent functions for the heat capacity and the heat conduction which were obtained by experimental measurements. The effect of latent heat occurring in the process is also taken into account. The heat equation is discretized in time and space where a Runge-Kutta method of Radau IIA type is used for time integration. An adaptive finite element method is applied for the discretization in space and the model is implemented into the finite element library deal.II. The heat and cooling rate as important process parameters are simulated for different beam velocities. The ability for computing these process parameters makes the simulation tool suited for optimizing the process management of selective beam melting plants.

  6. High-Pressure Melt Streaming (HIPS) program plan

    SciTech Connect (OSTI)

    Tarbell, W.; Brockmann, J.; Pilch, M.

    1984-08-01T23:59:59.000Z

    The Zion Probabilistic Safety Study (ZPSS) envisions accident sequences that could lead to failure of the reactor vessel while the primary system is pressurized. The resulting ejection of molten core material into the reactor cavity followed by the blowdown of steam and hydrogen is shown to cause the debris to enter into the containment region. The High Pressure Melt Streaming (HIPS) program has been developed to provide an experimental and analytical investigation of the scenario described above. One-tenth linear scale models of the Zion cavity region will be used to investigate the debris dispersal phenomena. Smaller-scale experiments (SPIT-tests) are also used to study high-velocity jets, jet-water interactions, and 1/20th scale cavity geometries. Both matrices are developed using a factorial design approach. The document describes certain aspects of the ZPSS ex-vessel phenomena, the experimental matrices, test equipment, and instrumentation, and the program's analytical efforts. Preliminary data from SPIT testing are included.

  7. Melt extrusion and continuous manufacturing of pharmaceutical materials

    E-Print Network [OSTI]

    Bell, Erin R

    2011-01-01T23:59:59.000Z

    Melt extrusion is an alternative processing technique that operates continuously, reduces the total number of unit operations, allows for incorporation of difficult-to-process drug substances, and has the potential to ...

  8. Variational bounds for the shear viscosity of gelling melts

    E-Print Network [OSTI]

    Claas H. Köhler; Henning Löwe; Peter Müller; Annette Zippelius

    2007-05-03T23:59:59.000Z

    We study shear stress relaxation for a gelling melt of randomly crosslinked, interacting monomers. We derive a lower bound for the static shear viscosity $\\eta$, which implies that it diverges algebraically with a critical exponent $k\\ge 2\

  9. Melt generation in the Earth's mantle at Convergent Plate Margins

    E-Print Network [OSTI]

    Till, Christy B

    2011-01-01T23:59:59.000Z

    The five geologic studies presented in this thesis document how the recycling of tectonic plates at subduction zones has a profound effect on the melting behavior of the Earth's mantle. Two experimental studies (Chapters ...

  10. Characterization of electron beam melted uranium - 6% niobium ingots

    SciTech Connect (OSTI)

    McKoon, R.H.

    1997-10-31T23:59:59.000Z

    A study was undertaken at Lawrence Livermore National Laboratory to characterize uranium, 6{percent} niobium ingots produced via electron beam melting,hearth refining and continuous casting and to compare this material with conventional VIM/skull melt /VAR material. Samples of both the ingot and feed material were analyzed for niobium, trace metallic elements, carbon, oxygen and nitrogen. Ingot samples were also inspected metallographically and via microprobe analysis.

  11. Apparatus for melt growth of crystalline semiconductor sheets

    DOE Patents [OSTI]

    Ciszek, Theodore F. (Evergreen, CO); Hurd, Jeffery L. (Golden, CO)

    1986-01-01T23:59:59.000Z

    An economical method is presented for forming thin sheets of crystalline silicon suitable for use in a photovoltaic conversion cell by solidification from the liquid phase. Two spatially separated, generally coplanar filaments wettable by liquid silicon and joined together at the end by a bridge member are immersed in a silicon melt and then slowly withdrawn from the melt so that a silicon crystal is grown between the edge of the bridge and the filaments.

  12. Method and apparatus for melt growth of crystalline semiconductor sheets

    DOE Patents [OSTI]

    Ciszek, T.F.; Hurd, J.L.

    1981-02-25T23:59:59.000Z

    An economical method is presented for forming thin sheets of crystalline silicon suitable for use in a photovoltaic conversion cell by solidification from the liquid phase. Two spatially separated, generally coplanar filaments wettable by liquid silicon and joined together at the end by a bridge member are immersed in a silicon melt and then slowly withdrawn from the melt so that a silicon crystal is grown between the edge of the bridge and the filaments.

  13. Velocity of sound in solid methane near melting temperatures

    E-Print Network [OSTI]

    Whitehead, John Martin

    1968-01-01T23:59:59.000Z

    VELOCITY OF SOUND IN SOLID METHANE NEAR MELTING TEMPERATURES A Thesis By JOHN MARTIN WHITEHEAD Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May... 1968 Ma)or Sub)ect: Physics VELOCITY OF SOVND IN SOLID METHANE NEAR MELTING TEMPERATURES A Thesis By JOHN MARTIN WHITEHEAD Approved as to style and content by& (Chairman of Committee) (Head of Departsmnt) (Mem er (Member) May 1968...

  14. The addition of a calender machine to a pyrolytic graphite sheet production plant

    E-Print Network [OSTI]

    Svenson, Ernest Knute

    2014-01-01T23:59:59.000Z

    This thesis documents the process and challenges of adding a new calender machine to AvCarb Material Solutions' pyrolytic graphite production plant. Before the machine could be used for mass production, several experiments ...

  15. Oxidation of hydrocarbons over ordered arrays of heteropolyacids and polyoxoanions on graphite

    DOE Patents [OSTI]

    Shaikh, Shahid N. (Media, PA); Ellis, Jr., Paul E. (Downingtown, PA); Lyons, James E. (Wallingford, PA)

    1994-01-01T23:59:59.000Z

    Alkanes are catalytically oxidized using heteropolyacids (HPAs) or polyoxoanions (POAs) deposited on a graphite surface. The HPAs and POAs are framework-substituted with a different metal in place of a metal-oxygen unit.

  16. Large-scale preparation of graphene by high temperature insertion of hydrogen into graphite

    E-Print Network [OSTI]

    Kamali, Ali Reza; Fray, Derek J.

    2015-05-14T23:59:59.000Z

    Experimental evidence for high temperature diffusion of hydrogen into the interlayer space of graphite is provided. This process is discussed as a possible method for the rapid production of high-quality, inexpensive graphene in large quantities...

  17. Low-Cost Graphite and Olivine-Based Materials for Li-Ion Batteries

    Broader source: Energy.gov (indexed) [DOE]

    Graphite and Olivine-Based Materials for Li-Ion Batteries K. Zaghib Hydro-Qubec (IREQ), 1800 Lionel-Boulet Varennes, QC, Canada, J3X 1S1 BATT Review Meeting February 25 - 28,...

  18. Thermodynamic and kinetic properties of the Li-graphite system from first-principles calculations

    E-Print Network [OSTI]

    Ceder, Gerbrand

    We present an ab initio study of the thermodynamics and kinetics of Li [subscript x]C[subscript 6], relevant for anode Li intercalation in rechargeable Li batteries. In graphite, the interlayer interactions are dominated ...

  19. Claisen Rearrangement of Graphite Oxide: A Route to Covalently Functionalized Graphenes

    E-Print Network [OSTI]

    Collins, William R.

    On the GO: The basal plane allylic alcohol functionality of graphite oxide (GO) can be converted into N,N-dimethylamide groups through an Eschenmoser–Claisen sigmatropic rearrangement by using N,N-dimethylacetamide dimethyl ...

  20. Direct Observation of Optically Induced Transient Structures in Graphite Using Ultrafast Electron Crystallography

    E-Print Network [OSTI]

    initio density functional calculations, we trace the governing mechanism back to electronic structure changes in the electronic properties, direct de- termination of lattice structural dynamics from opticalDirect Observation of Optically Induced Transient Structures in Graphite Using Ultrafast Electron

  1. The effects of marine microorganisms on the mechanical properties of graphite/epoxy composites 

    E-Print Network [OSTI]

    Puh, John Shui-Ming

    1997-01-01T23:59:59.000Z

    with two different lay-ups were conditioned in natural seawater and then tensile tested while simultaneously monitored for acoustic emission activity. Graphite/epoxy composite specimens were fabricated from prepreg tape and then conditioned for 4 and I I...

  2. Wetting transition behavior of Xe on Cs and Cs/graphite Stefano Curtarolo,1,

    E-Print Network [OSTI]

    Curtarolo, Stefano

    Wetting transition behavior of Xe on Cs and Cs/graphite Stefano Curtarolo,1, * Milton W. Cole,2 surface, covered by a monolayer of Cs. With data obtained from grand canonical Monte Carlo simulations

  3. Absolute x-ray dosimetry on a synchrotron medical beam line with a graphite calorimeter

    SciTech Connect (OSTI)

    Harty, P. D., E-mail: Peter.Harty@arpansa.gov.au; Ramanathan, G.; Butler, D. J.; Johnston, P. N. [Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085 (Australia)] [Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085 (Australia); Lye, J. E. [Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085, Australia and Australian Clinical Dosimetry Service, Yallambie, Victoria 3085 (Australia)] [Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085, Australia and Australian Clinical Dosimetry Service, Yallambie, Victoria 3085 (Australia); Hall, C. J. [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168 (Australia)] [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168 (Australia); Stevenson, A. W. [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168, Australia and CSIRO, Materials Science and Engineering, Clayton Sth Victoria 3169 (Australia)] [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168, Australia and CSIRO, Materials Science and Engineering, Clayton Sth Victoria 3169 (Australia)

    2014-05-15T23:59:59.000Z

    Purpose: The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and provide confidence in the first implementation of a graphite calorimeter on a synchrotron medical beam line. Methods: The graphite calorimeter has a core which rises in temperature when irradiated by the beam. A collimated x-ray beam from the synchrotron with well-defined edges was used to partially irradiate the core. Two filtration sets were used, one corresponding to an average beam energy of about 80 keV, with dose rate about 50?Gy/s, and the second filtration set corresponding to average beam energy of 90 keV, with dose rate about 20 Gy/s. The temperature rise from this beam was measured by a calibrated thermistor embedded in the core which was then converted to absorbed dose to graphite by multiplying the rise in temperature by the specific heat capacity for graphite and the ratio of cross-sectional areas of the core and beam. Conversion of the measured absorbed dose to graphite to absorbed dose to water was achieved using Monte Carlo calculations with the EGSnrc code. The air kerma measurements from the free-air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. Results: Absolute measurements of the IMBL dose rate were made using the graphite calorimeter and compared to measurements with the free-air chamber. The measurements were at three different depths in graphite and two different filtrations. The calorimetry measurements at depths in graphite show agreement within 1% with free-air chamber measurements, when converted to absorbed dose to water. The calorimetry at the surface and free-air chamber results show agreement of order 3% when converted to absorbed dose to water. The combined standard uncertainty is 3.9%. Conclusions: The good agreement of the graphite calorimeter and free-air chamber results indicates that both devices are performing as expected. Further investigations at higher dose rates than 50?Gy/s are planned. At higher dose rates, recombination effects for the free-air chamber are much higher and expected to lead to much larger uncertainties. Since the graphite calorimeter does not have problems associated with dose rate, it is an appropriate primary standard detector for the synchrotron IMBL x rays and is the more accurate dosimeter for the higher dose rates expected in radiotherapy applications.

  4. Melt Rate Improvement for High-Level Waste Glass

    SciTech Connect (OSTI)

    Matyas, Josef; Hrma, Pavel R.; Kim, Dong-Sang

    2002-09-09T23:59:59.000Z

    This report summarizes results of research accomplished during the first year of the 3-year project. The data presented in this report have been gathered to support work on the mathematical modeling of waste-glass melters. At this stage, only a qualitative description and interpretation of the observed phenomena has been attempted. Two Savannah Rive feeds were used for the study. These feeds were subjected to thermal gravimetric analysis, differential thermal analysis, differential scanning calorimetry, evolved gas analysis with volume-expansion monitoring, modified reboil test, quantitative X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, wet chemical analysis, and M?ssbauer spectroscopy. Glass viscosity was also measured. Finally, it was recommended to use melt-rate furnace test data to measure thermal diffusivity of the feed. Though both feed were reduced to prevent oxygen evolution from the melt, oxygen evolved form one of the melts and COx evolved from both. Hence, foam is likely to form under the cold cap even when the feed is reduced. An important difference between the feeds was in the melt viscosity at the temperature at which the melt interfaces the cold cap. It was suggested that low viscosity destabilizes foam under the cold cap, thus enhancing the rate of melting.

  5. Solidification microstructures in single-crystal stainless steel melt pools

    SciTech Connect (OSTI)

    Sipf, J.B.; Boatner, L.A.; David, S.A.

    1994-03-01T23:59:59.000Z

    Development of microstructure of stationary melt pools of oriented stainless steel single crystals (70%Fe-15%Ni-15%Cr was analyzed. Stationary melt pools were formed by electron-beam and gas-tungsten-arc heating on (001), (011), and (111) oriented planes of the austenitic, fcc-alloy crystals. Characterization and analysis of resulting microstructure was carried out for each crystallographic plane and welding method. Results showed that crystallography which favors ``easy growth`` along the <100> family of directions is a controlling factor in the microstructural formation along with the melt-pool shape. The microstructure was found to depend on the melting method, since each method forms a unique melt-pool shape. These results are used in making a three-dimensional reconstruction of the microstructure for each plane and melting method employed. This investigation also suggests avenues for future research into the microstructural properties of electron-beam welds as well as providing an experimental basis for mathematical models for the prediction of solidification microstructures.

  6. Effect of graphite properties in thermal analysis of CHTR: A parametric study

    SciTech Connect (OSTI)

    Kaushik, Ankur; Basak, Abhishek; Dulera, I. V.; Vijayan, P. K. [Reactor Engineering Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

    2013-06-12T23:59:59.000Z

    Compact High Temperature Reactor (CHTR) is a {sup 233}U-Thorium fuelled, lead-bismuth cooled reactor. The CHTR core mainly consists of graphite and beryllium oxide (BeO). The CHTR core consists of nineteen prismatic beryllium oxide (BeO) moderator blocks. These 19 blocks contain centrally located graphite fuel tubes. The BeO moderator blocks are surrounded by reflector blocks (partially graphite and partially BeO). The nuclear heat from the core is removed passively by natural circulation of the coolant between top and bottom plenums, upward through the fuel tubes and returning through the downcomer tubes at the periphery. The temperature gradient in fuel tubes, downcomer tubes and BeO is very high and therefore, to take care of the differential thermal expansion, gaps are provided in the core between the tubes and other core components. These gaps affect the heat transfer through the core in radial direction. In addition, there is a large variation in thermal properties of graphite which in turn affects the thermal behaviour of the core in various operating conditions. The fuel of CHTR is TRISO coated particle fuel. These particles are packed in with graphite powder as matrix and made into cylindrical compacts these compacts are packed in the bores of fuel tube. In this study, the effect of the thermal conductivity variation of the graphite on the temperature distribution of the core and density variation of the matrix graphite material in fuel compact on the maximum fuel kernel temperature is studied along with the overall role of graphite properties variation in heat transfer.

  7. Evaluation of hole quality and bit life in graphite epoxy composites using video scanning

    E-Print Network [OSTI]

    Lednicky, Thomas Edward

    1985-01-01T23:59:59.000Z

    . Hough J (Chairman of Commit ee) D . R. M. Alexander (Member) ( e&/ Dr, J. Bo sford (Memb r) W. . Turner (Head o Department) December 1985 ABSTRACT EVALUATION OF HOLE QUALITY AND BIT LIFE IN GRAPHITE EPOXY COMPOSITES USING VIDEO SCANNING... extensively in graphite epoxy composite material. This evaluation was accomplished by measuring the hole quality and also the wear land development. Two methods were used to determine the hole quality on a computer vision system: the hole size...

  8. Mode II delamination fracture toughness of unidirectional graphite/epoxy composites 

    E-Print Network [OSTI]

    Corleto Mena, Carlos Roberto

    1986-01-01T23:59:59.000Z

    MODE II DELAMINATION FRACTURE TOUGHNESS OF UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITES A Thesis by CARLOS ROBERTO CORLETO MENA Submitted to the Graduate College of TEXAS ASM UNIVERSITY in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1986 Major Subject: Mechanical Engineering MODE II DELAMINATION FRACTURE TOUGHNESS OF UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITES A Thesis by CARLOS ROBERTO CORLETO MENA Approved as to style and content by: Walter L. Bra...

  9. The effect of graphite nodules on fracture behavior of ductile iron 

    E-Print Network [OSTI]

    Tanner, Glenn Mark

    1986-01-01T23:59:59.000Z

    THE EFFECT OF GRAPHITE NODULES ON FRACTURE BEHAVIOR OF DUCTILE IRON A Thesis By GLENN NARK TANNER Suhmitted to the Graduate College of Texas A&K University in partial fulfillment of the requirements for the degree of RASTER OF SCIENCE Nay... 1986 Kajor Subject: Nechanical Engineering THE EFFECT OF GRAPHITE NODULES ON FRACTURE BEHAVIOR OF DUCTILE IRON A Thesis by GLENN MARK TANNER Approved as to style and content by: Halter L. Bradley (Chairman of Committee) pl...

  10. Residual thermal stresses in an unsymmetrical cross-ply graphite/epoxy laminate 

    E-Print Network [OSTI]

    Harper, Brian Douglas

    1980-01-01T23:59:59.000Z

    RESIDUAL THERMAL STRESSES IN AN UNSYMMETRICAL CROSS-PLY GRAPHITE/EPOXY LAMINATE A Thesis by BRIAN DOUGLAS HARPER Submitted to the Graduate College of Texas A&M University in parrial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1980 Major Subject: Mechanical Engineering RESIDUAL THERMAL STRESSES IN AN UNSYMMETRICAL CROSS-PLY GRAPHITE/EPOXY LAMINATE A Thesis by BRIAN DOUGLAS HARPER Approved as to style and content by: r. Y. N itsman (Chair of Committee) Dr...

  11. Nondestructive evaluation of distributed damage in graphite/epoxy beams using modal parameters 

    E-Print Network [OSTI]

    Kim, Young Ik

    1989-01-01T23:59:59.000Z

    NONDESTRUCTIVE EVALUATIOV OF DISTRIBUTED DAMAGE IN GRAPHITE/EPOXY BEAMS USING MODAL PARAMETERS A Thesis YOUNG IK KIM Submitted to the Office of Graduate Studies of Texas AkM University in partial fulfillment of the requirement for the degree... of ItIASTER OF SCIEVCE August 1989 Major Subject: Aerospace Engineering NONDESTRI. 'CTIVE EVALUATION OF DISTRIBUTED DAMAGE IN GRAPHITE/EPOXY BEAMS USING MODAL PARAMETERS A Thesis by YOUNG IK KIM Approved as to style and content by: Duane R...

  12. Mode I - mode II delamination fractrue toughness of a unidirectional graphite/epoxy composite 

    E-Print Network [OSTI]

    Vanderkley, Peter Stephen

    1981-01-01T23:59:59.000Z

    MODE I - MODE II DELAMINATION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by PETER STEPHEN VANDERKLEY Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE Demember 1981 Najor Subject: Mechanical Engineering MODE I - MODE II DELAMINATION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by PETER STEPHEN VANDERKLEY Approved as to style and content by...

  13. Effect of resin toughness on fracture behavior of graphite/epoxy composites 

    E-Print Network [OSTI]

    Cohen, Ronald Nelson

    1982-01-01T23:59:59.000Z

    EFFECT OF RESIN TOUGHNESS ON FRACTURE BEHAVIOR OF GRAPHITE/EPOXY COMPOSITES A Thesis Dy RONALD NELSON COHEN Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1982 Mlajor Subject: Interdisciplinary Enqi neeri ng EFFECT OF RESIN TOUGHNESS ON FRACTURE BEHAVIOR OF GRAPHITE/EPOXY COMPOSITES A Thesis by RONALD NELSON COHEN Approved as to style and content by: (N. L. Bradley, Cha man) (R. A...

  14. Nonlinear viscoelastic characterization of AS-3502 graphite/epoxy composite material 

    E-Print Network [OSTI]

    Kerstetter, Michael Scott

    1980-01-01T23:59:59.000Z

    NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis MICHAEL SCOTT KERSTETTER Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1980 Major Subject: Aerospace Engineering NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis by MICHAEL SCOTT KERSTETTER Approved as to style and content by: Dr. Kenneth L...

  15. Measurements of the diffusion coefficient of silver 110-m in a nuclear grade graphite 

    E-Print Network [OSTI]

    McMillan, Thad Calhoun

    1980-01-01T23:59:59.000Z

    MEASUREMENTS OF TEE DIFFUSION COEFFICIENT OF SILVER 110-m IN A NUCLEAR GRADE. GRAPHITE A Thesis by THAD CALHOUN MCMILLAN, Jr. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1980 Major Subject: Nuclear Engineering MEASUREMENTS OF THE DIFFUSION COEFFICIENT OF SILVER 110-m IN A NUCLEAR GRADE GRAPHITE A Thesis by THAD CALHOUN MCMILLAN, Jr. Approved as to style and content by: (Chairman...

  16. Stresses due to environmental conditioning of cross-ply graphite/epoxy laminates 

    E-Print Network [OSTI]

    Douglass, David Alan

    1979-01-01T23:59:59.000Z

    STRESSES DUE TO ENVIRONMENTAL CONDITIONING OF CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by DAVID ALAN DOUGLASS Submitted to the Graduate College of Texas AIM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1979 Major Subject: Aerospace Engineering STRESSES DUE TO ENVIRONMENTAL CONDITIONING OF CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by DAVID ALAN DOUGLASS Approved as to style and content by: Dr. . Weitsman Chasrm n of Comittee g...

  17. Melt segregation under compaction and shear channelling: Application to granitic magma segregation in a continental crust

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Melt segregation under compaction and shear channelling: Application to granitic magma segregation in a mush submitted to both compaction and shear. It applies to a granitic melt imbedded within of melt to about 20 % in total to be extracted from the matrix. Abridged title Granitic melt segregation

  18. Method for processing aluminum spent potliner in a graphite electrode arc furnace

    DOE Patents [OSTI]

    O'Connor, William K.; Turner, Paul C.; Addison, G.W. (AJT Enterprises, Inc.)

    2002-12-24T23:59:59.000Z

    A method of processing spent aluminum pot liner containing carbon, cyanide compositions, fluorides and inorganic oxides. The spend aluminum pot liner is crushed, iron oxide is added to form an agglomerated material. The agglomerated material is melted in an electric arc furnace having the electrodes submerged in the molten material to provide a reducing environment during the furnace operation. In the reducing environment, pot liner is oxidized while the iron oxides are reduced to produce iron and a slag substantially free of cyanide compositions and fluorides. An off-gas including carbon oxides and fluorine is treated in an air pollution control system with an afterburner and a scrubber to produce NaF, water and a gas vented to the atmosphere free of cyanide compositions, fluorine, and CO.

  19. Method for processing aluminum spent potliner in a graphite electrode ARC furnace

    DOE Patents [OSTI]

    O'Connor, William K. (Lebanon, OR); Turner, Paul C. (Independence, OR); Addison, Gerald W. (St. Stephen, SC)

    2002-12-24T23:59:59.000Z

    A method of processing spent aluminum pot liner containing carbon, cyanide compositions, fluorides and inorganic oxides. The spent aluminum pot liner is crushed iron oxide is added to form an agglomerated material. The agglomerated material is melted in an electric arc furnace having the electrodes submerged in the molten material to provide a reducing environment during the furnace operation. In the reducing environment, pot liner is oxidized while the iron oxides are reduced to produce iron and a slag substantially free of cyanide compositions and fluorides. An off-gas including carbon oxides and fluorine is treated in an air pollution control system with an afterburner and a scrubber to produce NaF, water and a gas vented to the atmosphere free of cyanide compositions, fluorine and CO.

  20. NMR studies of molecules in liquid crystals and graphite

    SciTech Connect (OSTI)

    Rosen, M.E.

    1992-06-01T23:59:59.000Z

    NMR experiments to measure proton dipole couplings were performed on a series of n-alkanes (n-hexane through n-decane) dissolved in nematic liquid crystals. Computer modeling of the experimental NMR-spectra was done using several different models for intermolecular interactions in these systems. The model of Photinos et al. was found to be best in describing the intermolecular interactions in these systems and can provide a statistical picture of the conformation and orientation of the alkane molecules in their partially-oriented environment. Order parameters and conformational distributions for the alkanes can be calculated from the modeling. The alkanes are found to have conformational distributions very much like those found in liquid alkanes. Proton NMR spectra of tetrahydrofuran (THF) intercalated in two graphite intercalation compounds were also measured. Computer simulations of these spectra provide a picture of THF in the constrained environment between the graphene layers where the THF is oriented at a particular angle, can translate and rotate freely, but does not appear to pseudorotate.

  1. Internal degrees of freedom and transport of benzene on graphite

    E-Print Network [OSTI]

    Astrid S. de Wijn

    2011-07-13T23:59:59.000Z

    In this paper, the chaotic internal degrees of freedom of a benzene molecule adsorbed on a graphite substrate, their interplay with thermal noise, and their effects on the diffusion and drift are investigated analytically by making use of the presence of two different time scales as well as by molecular-dynamics simulations. The effects of thermal noise are investigated, and it is found that noise does not significantly alter the dynamics of the internal degrees of freedom, yet affects the friction and diffusion of the center of mass. Qualitative and quantitative theoretical predictions for the friction and diffusion of the molecule on the substrate are made and are compared to molecular-dynamics simulations. Contributions to the friction and diffusion from the finite heat bath as well as the slow dynamics of the center of mass are formally identified. It is shown that the torsion in benzene, which dominates the nonlinear coupling, significantly affects the friction of the molecule on the surface. The results compare favorably with recent results from He/neutron spin echo experiments on this system. Based on the analytical and numerical results, some suggestions are made for experimental conditions under which the effects of internal degrees of freedom might be observable.

  2. Graphite electrode arc melter demonstration Phase 2 test results

    SciTech Connect (OSTI)

    Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; O`Connor, W.K.; Oden, L.L.; Turner, P.C.

    1996-06-01T23:59:59.000Z

    Several U.S. Department of Energy organizations and the U.S. Bureau of Mines have been collaboratively conducting mixed waste treatment process demonstration testing on the near full-scale graphite electrode submerged arc melter system at the Bureau`s Albany (Oregon) Research Center. An initial test series successfully demonstrated arc melter capability for treating surrogate incinerator ash of buried mixed wastes with soil. The conceptual treatment process for that test series assumed that buried waste would be retrieved and incinerated, and that the incinerator ash would be vitrified in an arc melter. This report presents results from a recently completed second series of tests, undertaken to determine the ability of the arc melter system to stably process a wide range of {open_quotes}as-received{close_quotes} heterogeneous solid mixed wastes containing high levels of organics, representative of the wastes buried and stored at the Idaho National Engineering Laboratory (INEL). The Phase 2 demonstration test results indicate that an arc melter system is capable of directly processing these wastes and could enable elimination of an up-front incineration step in the conceptual treatment process.

  3. Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Clean Steel Casting Production

    SciTech Connect (OSTI)

    Kuyucak, Selcuk [CanmetMATERIALS; Li, Delin [CanmetMATERIALS

    2013-12-31T23:59:59.000Z

    Inclusions in steel castings can cause rework, scrap, poor machining, and reduced casting performance, which can obviously result in excess energy consumption. Significant progress in understanding inclusion source, formation and control has been made. Inclusions can be defined as non-metallic materials such as refractory, sand, slag, or coatings, embedded in a metallic matrix. This research project has focused on the mold filling aspects to examine the effects of pouring methods and gating designs on the steel casting cleanliness through water modeling, computer modeling, and melting/casting experiments. Early in the research project, comprehensive studies of bottom-pouring water modeling and low-alloy steel casting experiments were completed. The extent of air entrainment in bottom-poured large castings was demonstrated by water modeling. Current gating systems are designed to prevent air aspiration. However, air entrainment is equally harmful and no prevention measures are in current practice. In this study, new basin designs included a basin dam, submerged nozzle, and nozzle extension. The entrained air and inclusions from the gating system were significantly reduced using the new basin method. Near the end of the project, there has been close collaboration with Wescast Industries Inc., a company manufacturing automotive exhaust components. Both computer modeling using Magma software and melting/casting experiments on thin wall turbo-housing stainless steel castings were completed in this short period of time. Six gating designs were created, including the current gating on the pattern, non-pressurized, partially pressurized, naturally pressurized, naturally pressurized without filter, and radial choke gating without filter, for Magma modeling. The melt filling velocity and temperature were determined from the modeling. Based on the simulation results, three gating designs were chosen for further melting and casting experiments on the same casting pattern using the lip pouring method. It was observed again that gating designs greatly influenced the melt filling velocity and the number of inclusion defects. The radial choked gating showed improvements in casting cleanliness and yield over the other gatings, even though no mold filters were used in the gating system.

  4. Graphite grains in supernova ejecta Insights from a noble gas study of 91 individual KFC1 presolar graphite grains from the

    E-Print Network [OSTI]

    Graphite grains in supernova ejecta ­ Insights from a noble gas study of 91 individual KFC1 Zu¨rich, Switzerland b Lund University, Department of Geology, So¨lvegatan 12, SE-22362 Lund, Sweden Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA d Chicago Center

  5. 07/06/2009 Melting Ice Could Lead to Massive Waves of Climate Refugees Treehugger 06/30/2009 MELTING GREENLAND ICE SHEETS MAY THREATEN

    E-Print Network [OSTI]

    Hu, Aixue

    /30/2009 MELTING GREENLAND ICE SHEETS MAY THREATEN NORTHEAST U.S., CANADA Federal News Service 06/30/2009 Sea raises spectre of displaced humanity peopleandplanet.net 06/16/2009 Melting Greenland Ice Sheets May Report - Online 06/02/2009 Melting Greenland Ice Sheets May Threaten Northeast, Canada usagnet 06

  6. Device and method for skull-melting depth measurement

    DOE Patents [OSTI]

    Lauf, Robert J. (Oak Ridge, TN); Heestand, Richard L. (Oak Ridge, TN)

    1993-01-01T23:59:59.000Z

    A method of skull-melting comprises the steps of: a. providing a vessel adapted for a skull-melting process, the vessel having an interior, an underside, and an orifice in connecting the interior and the underside; b. disposing a waveguide in the orifice so that the waveguide protrudes sufficiently into the interior to interact with the skull-melting process; c. providing a signal energy transducer in signal communication with the waveguide; d. introducing into the vessel a molten working material; e. carrying out the skull-melting process so that a solidified skull of the working material is formed, the skull and the vessel having an interface therebetween, the skull becoming fused to the waveguide so the signal energy can be transmitted through the waveguide and the skull without interference from the interface; f. activating the signal energy transducer so that a signal is propagated through the waveguide; and, g. controlling at least one variable of the skull-melting process utilizing feedback information derived from the propagated signal energy.

  7. Device and method for skull-melting depth measurement

    DOE Patents [OSTI]

    Lauf, R.J.; Heestand, R.L.

    1993-02-09T23:59:59.000Z

    A method of skull-melting comprises the steps of: (a) providing a vessel adapted for a skull-melting process, the vessel having an interior, an underside, and an orifice connecting the interior and the underside; (b) disposing a waveguide in the orifice so that the waveguide protrudes sufficiently into the interior to interact with the skull-melting process; (c) providing a signal energy transducer in signal communication with the waveguide; (d) introducing into the vessel a molten working material; (e) carrying out the skull-melting process so that a solidified skull of the working material is formed, the skull and the vessel having an interface therebetween, the skull becoming fused to the waveguide so the signal energy can be transmitted through the waveguide and the skull without interference from the interface; (f) activating the signal energy transducer so that a signal is propagated through the waveguide; and, (g) controlling at least one variable of the skull-melting process utilizing feedback information derived from the propagated signal energy.

  8. Validation of the THIRMAL-1 melt-water interaction code

    SciTech Connect (OSTI)

    Chu, C.C.; Sienicki, J.J.; Spencer, B.W.

    1995-05-01T23:59:59.000Z

    The THIRMAL-1 computer code has been used to calculate nonexplosive LWR melt-water interactions both in-vessel and ex-vessel. To support the application of the code and enhance its acceptability, THIRMAL-1 has been compared with available data from two of the ongoing FARO experiments at Ispra and two of the Corium Coolant Mixing (CCM) experiments performed at Argonne. THIRMAL-1 calculations for the FARO Scoping Test and Quenching Test 2 as well as the CCM-5 and -6 experiments were found to be in excellent agreement with the experiment results. This lends confidence to the modeling that has been incorporated in the code describing melt stream breakup due to the growth of both Kelvin-Helmholtz and large wave instabilities, the sizes of droplets formed, multiphase flow and heat transfer in the mixing zone surrounding and below the melt stream, as well as hydrogen generation due to oxidation of the melt metallic phase. As part of the analysis of the FARO tests, a mechanistic model was developed to calculate the prefragmentation as it may have occurred when melt relocated from the release vessel to the water surface and the model was compared with the relevant data from FARO.

  9. Curvature fluctuations and the Lyapunov exponent at melting

    SciTech Connect (OSTI)

    Mehra, V.; Ramaswamy, R. [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)] [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)

    1997-09-01T23:59:59.000Z

    We calculate the maximal Lyapunov exponent in constant-energy molecular-dynamics simulations at the melting transition for finite clusters of 6{endash}13 particles (model rare-gas and metallic systems) as well as for bulk rare-gas solids. For clusters, the Lyapunov exponent generally varies linearly with the total energy, but the {ital slope} changes sharply at the melting transition. In the bulk system, melting corresponds to a jump in the Lyapunov exponent, and this corresponds to a singularity in the variance of the curvature of the potential-energy surface. In these systems there are two mechanisms of chaos{emdash}local instability and parametric instability. We calculate the contribution of the parametric instability toward the chaoticity of these systems using a recently proposed formalism. The contribution of parametric instability is a continuous function of energy in small clusters but not in the bulk where the melting corresponds to a decrease in this quantity. This implies that the melting in small clusters does not lead to enhanced local instability. {copyright} {ital 1997} {ital The American Physical Society}

  10. Characterization of Porosity Development in Oxidized Graphite using Automated Image Analysis Techniques

    SciTech Connect (OSTI)

    Contescu, Cristian I [ORNL; Burchell, Timothy D [ORNL

    2009-09-01T23:59:59.000Z

    This document reports on initial activities at ORNL aimed at quantitative characterization of porosity development in oxidized graphite specimens using automated image analysis (AIA) techniques. A series of cylindrical shape specimens were machined from nuclear-grade graphite (type PCEA, from GrafTech International). The specimens were oxidized in air to various levels of weight loss (between 5 and 20 %) and at three oxidation temperatures (between 600 and 750 oC). The procedure used for specimen preparation and oxidation was based on ASTM D-7542-09. Oxidized specimens were sectioned, resin-mounted and polished for optical microscopy examination. Mosaic pictures of rectangular stripes (25 mm x 0.4 mm) along a diameter of sectioned specimens were recorded. A commercial software (ImagePro) was evaluated for automated analysis of images. Because oxidized zones in graphite are less reflective in visible light than the pristine, unoxidized material, the microstructural changes induced by oxidation can easily be identified and analyzed. Oxidation at low temperatures contributes to development of numerous fine pores (< 100 m2) distributed more or less uniformly over a certain depth (5-6 mm) from the surface of graphite specimens, while causing no apparent external damage to the specimens. In contrast, oxidation at high temperatures causes dimensional changes and substantial surface damage within a narrow band (< 1 mm) near the exposed graphite surface, but leaves the interior of specimens with little or no changes in the pore structure. Based on these results it appears that weakening and degradation of mechanical properties of graphite materials produced by uniform oxidation at low temperatures is related to the massive development of fine pores in the oxidized zone. It was demonstrated that optical microscopy enhanced by AIA techniques allows accurate determination of oxidant penetration depth and of distribution of porosity in oxidized graphite materials.

  11. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

    DOE Patents [OSTI]

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-05-20T23:59:59.000Z

    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  12. Precambrian coal or anthraxolite: A source for graphite in high-grade schists and gneisses-a reply

    SciTech Connect (OSTI)

    Mancuso, J.J.; Seavoy, R.E.

    1982-08-01T23:59:59.000Z

    Argues that without considering data for igneous carbon (carbonatites) or for ultrahigh metamorphic calcareous gneisses such as are found in the Grenville province of North America, the conclusion that the source of carbon for vein graphite is magmatic or carbonate carbon is not justified. Points out that marbles and calc-silicate gneisses occur with the graphite-bearing granulite facies rocks in Sri Lanka. Calcite may also be seen in the veins with the graphite. Concludes that whether the graphite in epigenetic veins in high grade schists and gneisses has variable carbon isotope ratios depends on whether it was derived from organic material in carbonate or noncarbonate metasediments.

  13. Effect of electrode density on cycle performance and irreversible capacity loss for natural graphite anode in lithium ion batteries

    SciTech Connect (OSTI)

    Shim, Joongpyo; Striebel, Kathryn A.

    2002-12-02T23:59:59.000Z

    The effect of electrode thickness and density for unpressed and pressed natural graphite electrodes were studied using electrochemical characterization. Pressing the graphite electrode decreases the reversible capacity and the irreversible capacity loss during formation. As electrode density increased, the capacity retention at high rate increased until 0.9g/cm{sup 3}, and then decreased. The cycle performances of the pressed graphite electrodes were more stable than the unpressed one. Pressing graphite electrode affected on its electrochemical characterization such as irreversible capacity loss, high rate cycling and cycle performance.

  14. FINAL REPORT on Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

    SciTech Connect (OSTI)

    Chang H. Oh; Eung S. Kim; Hee C. NO; Nam Z. Cho

    2011-01-01T23:59:59.000Z

    The U.S. Department of Energy is performing research and development that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP)/Generation IV very high temperature reactor (VHTR). Phenomena Identification and Ranking studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important. Consequently, the development of advanced air ingress-related models and verification & validation are of very high priority for the NGNP Project. Following a loss of coolant and system depressurization incident, air ingress will occur through the break, leading to oxidation of the in-core graphite structure and fuel. This study indicates that depending on the location and the size of the pipe break, the air ingress phenomena are different. In an effort to estimate the proper safety margin, experimental data and tools, including accurate multidimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model are required. It will also require effective strategies to mitigate the effects of oxidation, eventually. This 3-year project (FY 2008–FY 2010) is focused on various issues related to the VHTR air-ingress accident, including (a) analytical and experimental study of air ingress caused by density-driven, stratified, countercurrent flow, (b) advanced graphite oxidation experiments, (c) experimental study of burn-off in the core bottom structures, (d) structural tests of the oxidized core bottom structures, (e) implementation of advanced models developed during the previous tasks into the GAMMA code, (f) full air ingress and oxidation mitigation analyses, (g) development of core neutronic models, (h) coupling of the core neutronic and thermal hydraulic models, and (i) verification and validation of the coupled models.

  15. Melt processing of Bi--2212 superconductors using alumina

    DOE Patents [OSTI]

    Holesinger, Terry G. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    Superconducting articles and a method of forming them, where the superconducting phase of an article is Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.y (Bi-2212). Alumina is combined with Bi-2212 powder or Bi-2212 precursor powder and, in order to form an intimate mixture, the mixture is melted and rapidly cooled to form a glassy solid. The glassy solid is comminuted and the resulting powder is combined with a carrier. An alternative to melting is to form the mixture of nanophase alumina and material having a particle size of less than about 10 microns. The powder, with the carrier, is melt processed to form a superconducting article.

  16. Plasma arc melting of a 80 wt % tantalum-20 wt % titanium alloy

    SciTech Connect (OSTI)

    Dunn, P.S.; Patterson, R.A.

    1994-10-01T23:59:59.000Z

    An alloy of 80wt% tantalum-20wt% titanium is being considered for use in an oxidizing and highly corrosive liquid metal application. The high melting point of the alloy, 2400 C, and other physical properties narrowed the possible melting techniques. Previous melting experience with these materials by electron beam resulted in extensive vaporization of the titanium during the melt and poor chemical homogeneity. A technique has been developed using plasma arc melting to melt refractory alloys with very dissimilar densities and vapor pressures. The 80Ta--20Ti alloy falls into this category with the density of tantalum 16.5 g/cc and that of titanium 4.5 g/cc. The melting of these materials is further complicated by the high melting point of tantalum( 3020 C) and the relatively low boiling point of titanium( 3287 C). The plasma arc melting technique described results in good chemical homogeneity with ingot size quantities of material.

  17. Lattice cluster theory for polymer melts with specific interactions

    E-Print Network [OSTI]

    Wen-Sheng Xu; Karl F. Freed

    2014-07-12T23:59:59.000Z

    Despite the long-recognized fact that chemical structure and specific interactions greatly influence the thermodynamic properties of polymer systems, a predictive molecular theory that enables systematically addressing the role of chemical structure and specific interactions has been slow to develop even for polymer melts. While the lattice cluster theory (LCT) provides a powerful vehicle for understanding the influence of various molecular factors, such as monomer structure, on the thermodynamic properties of polymer melts and blends, the application of the LCT has heretofore been limited to the use of the simplest polymer model in which all united atom groups within the monomers of a species interact with a common monomer averaged van der Waals energy. Thus, the description of a compressible polymer melt involves a single van der Waals energy. As a first step towards developing more realistic descriptions to aid in the analysis of experimental data and the design of new materials, the LCT is extended here to treat models of polymer melts in which the backbone and side groups have different interaction strengths, so three energy parameters are present, namely, backbone-backbone, side group-side group, and backbone-side group interaction energies. Because of the great algebraic complexity of this extension, we retain maximal simplicity within this class of models by further specializing this initial study to models of polymer melts comprising chains with poly($n$-$\\alpha$-olefin) structures where only the end segments on the side chains may have different, specific van der Waals interaction energies with the other united atom groups. An analytical expression for the LCT Helmholtz free energy is derived for the new model. Illustrative calculations are presented to demonstrate the degree to which the thermodynamic properties of polymer melts can be controlled by specific interactions.

  18. Effect of glass-batch makeup on the melting process

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Schweiger, Michael J.; Humrickhouse, Carissa J.; Moody, J. Adam; Tate, Rachel M.; Rainsdon, Timothy T.; Tegrotenhuis, Nathan E.; Arrigoni, Benjamin M.; Marcial, Jose; Rodriguez, Carmen P.; Tincher, Benjamin

    2010-03-29T23:59:59.000Z

    The response of a glass batch to heating is determined by the batch makeup and in turn determines the rate of melting. Batches formulated for a high-alumina nuclear waste to be vitrified in an all-electric melter were heated at a constant temperature-increase rate to determine changes in melting behavior in response to the selection of batch chemicals and silica grain-size as well as the addition of heat-generating reactants. The type of batch materials and the size of silica grains determine how much, if any, primary foam occurs during melting. Small quartz grains, 5-?m in size, caused extensive foaming because their major portion dissolved at temperatures <800°C, contributing to the formation of viscous glass-forming melt that trapped evolving batch gases. Primary foam did not occur in batches with larger quartz grains, ?75 ?m in size, because their major portion dissolved at temperatures >800°C when batch gases no longer evolved. The exothermal reaction of nitrates with sucrose was ignited at a temperature as low as 160°C and caused a temporary jump in temperature of several hundred degrees. Secondary foam, the source of which is oxygen from redox reactions, occurred in all batches of a limited composition variation involving five oxides, B2O3, CaO, Li2O, MgO, and Na2O. The foam volume at the maximum volume-increase rate was a weak function of temperature and melt basicity. Neither the batch makeup nor the change in glass composition had a significant impact on the dissolution of silica grains. The impacts of primary foam generation on glass homogeneity and the rate of melting in large-scale continuous furnaces have yet to be established via mathematical modeling and melter experiments.

  19. EFFECT OF GLASS-BATCH MAKEUP ON THE MELTING PROCESS

    SciTech Connect (OSTI)

    KRUGER AA; HRMA P

    2010-12-07T23:59:59.000Z

    The response of a glass batch to heating is determined by the batch makeup and in turn determines the rate of melting. Batches formulated for a high-alumina nuclear waste to be vitrified in an all-electric melter were heated at a constant temperature-increase rate to determine changes in melting behavior in response to the selection of batch chemicals and silica grain-size as well as the addition of heat-generating reactants. The type of batch materials and the size of silica grains determine how much, if any, primary foam occurs during melting. Small quartz grains, 5 {micro}m in size, caused extensive foaming because their major portion dissolved at temperatures <800 C, contributing to the formation of viscous glass forming melt that trapped evolving batch gases. Primary foam did not occur in batches with larger quartz grains, {+-}75 {micro}m in size, because their major portion dissolved at temperatures >800 C when batch gases no longer evolved. The exothermal reaction of nitrates with sucrose was ignited at a temperature as low as 160 C and caused a temporary jump in temperature of several hundred degrees. Secondary foam, the source of which is oxygen from redox reactions, occurred in all batches of a limited composition variation involving five oxides, B{sub 2}O{sub 3}, CaO, Li{sub 2}O, MgO, and Na{sub 2}O. The foam volume at the maximum volume-increase rate was a weak function of temperature and melt basicity. Neither the batch makeup nor the change in glass composition had a significant impact on the dissolution of silica grains. The impacts of primary foam generation on glass homogeneity and the rate of melting in large-scale continuous furnaces have yet to be established via mathematical modeling and melter experiments.

  20. Methods of vitrifying waste with low melting high lithia glass compositions

    DOE Patents [OSTI]

    Jantzen, Carol M. (Aiken, SC); Pickett, John B. (Aiken, SC); Cicero-Herman, Connie A. (Aiken, SC); Marra, James C. (Aiken, SC)

    2001-01-01T23:59:59.000Z

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  1. Decontamination and decarburization of stainless and carbon steel by melt refining

    SciTech Connect (OSTI)

    Mizia, R.E.; Worcester, S.A.; Twidwell, L.G.; Webber, D.; Paolini, D.J.; Weldon, T.A.

    1996-09-05T23:59:59.000Z

    With many nuclear reactors and facilities being decommissioned in the next ten to twenty years the concern for handling and storing Radioactive Scrap Metal (RSM) is growing. Upon direction of the DOE Office of Environmental Restoration and Waste Management, Lockheed Idaho Technology Company (LITCO) is developing technologies for the conditioning of spent fuels and high-level wastes for interim storage and repository acceptance, including the recycling of Radioactive Scrap Metals (RSM) for beneficial reuse with the DOE complex. In February 1993, Montana Tech of the University of Montana was contracted to develop and demonstrate technologies for the decontamination of stainless steel RSM. The general objectives of the Montana Tech research program included conducting a literature survey, performing laboratory scale melt refining experiments to optimize decontaminating slag compositions, performing an analysis of preferred melting techniques, coordinating pilot scale and commercial scale demonstrations, and producing sufficient quantities of surrogate-containing material for all of the laboratory, pilot and commercial scale test programs. Later on, the program was expanded to include decontamination of carbon steel RSM. Each research program has been completed, and results are presented in this report.

  2. Improving interface through surface modification by plasma polymerization, in carbon/graphite fiber reinforced polymeric composites

    SciTech Connect (OSTI)

    Dagli, N.G.

    1986-01-01T23:59:59.000Z

    Carbon/graphite fiber surfaces were modified by plasma polymerization. An inductively coupled electrodeless glow-discharge system was utilized to treat the surfaces with acrylonitrile or styrene at the established operating conditions. Critical surface erosion for wetting measured by the sessile drop method, of plasma treated pyrolytic graphite blocks, used as a model surface for carbon/graphite fibers, were lower than of untreated block. Contact angles on plasma polymers deposited on different substrates had similar values. Contact angle, measured by Wilhelmy balance method of water, on untreated Fortafil 3 carbon/graphite fiber was 55.1/sup 0/, whereas the commercially treated one was 43.7/sup 0/. Plasma treatments reduced the contact angle to 44.3/sup 0/ in An and 47.3/sup 0/ in styrene monomer cases. Thicknesses of plasma polymers deposited under the established optimum conditions, measured by ellipsometer, were 840 A for PPAN and 2192 A for PPST after one hour treatment. In conclusion, plasma treatments of carbon/graphite fibers are an effective alternative to existing methods for improving interfacial shear strengths and maintaining or improving the tensile strengths of the fibers.

  3. Hybrid redox polyether melts based on polyether-tailed counterions

    SciTech Connect (OSTI)

    Dickinson, E. V; Williams, M.E.; Hendrickson, S.M.; Masui, Hitoshi; Murray, R.W.

    1999-02-03T23:59:59.000Z

    Interesting ionic materials can be transformed into room temperature molten salts by combining them with polyether-tailed counterions such as polyether-tailed 2-sulfobenzoate (MePEG-BzSO{sub 3}{sup {minus}}) and polyethertailed triethylammonium (MePEG-Et{sub 3}N{sup +}). Melts containing ruthenium hexamine, metal trisbipyridines, metal trisphenanthrolines, and ionic forms of aluminum quinolate, anthraquinone, phthalocyanine, and porphyrins are described. These melts exhibit ionic conductivities in the 7 x 10{sup {minus}5} to 7 x 10{sup {minus}10} {Omega}{sup {minus}1} cm{sup {minus}1} range, which permit microelectrode voltammetry in the undiluted materials, examples of which are presented.

  4. Aerosol source term in high pressure melt ejection

    SciTech Connect (OSTI)

    Brockmann, J.E.; Tarbell, W.W.

    1984-11-01T23:59:59.000Z

    Pressurized ejection of melt from a reactor pressure vessel has been identified as an important element of a severe reactor accident. Copious aerosol production is observed when thermitically generated melts pressurized with nitrogen or carbon dioxide to 1.3 to 17 MPa are ejected into an air atmosphere. Aerosol particle size distributions measured in the tests have modes of about 0.5, 5, and > 10 ..mu..m. Mechanisms leading to formation of these multimodal size distributions are suggested. This aerosol is a potentially important fission product source term that has not been considered in previous severe accident analyses.

  5. FY-09 Report: Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

    SciTech Connect (OSTI)

    Chang H. Oh; Eung S. Kim

    2009-12-01T23:59:59.000Z

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in the Next Generation Nuclear Plant (NGNP)/Gen-IV very high temperature reactor (VHTR). Phenomena Identification and Ranking Studies to date have identified that an air ingress event following on the heels of a VHTR depressurization is a very important incident. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority for the NGNP Project. Following a loss of coolant and system depressurization incident, air will enter the core through the break, leading to oxidation of the in-core graphite structure and fuel. If this accident occurs, the oxidation will accelerate heat-up of the bottom reflector and the reactor core and will eventually cause the release of fission products. The potential collapse of the core bottom structures causing the release of CO and fission products is one of the concerns. Therefore, experimental validation with the analytical model and computational fluid dynamic (CFD) model developed in this study is very important. Estimating the proper safety margin will require experimental data and tools, including accurate multidimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model. It will also require effective strategies to mitigate the effects of oxidation. The results from this research will provide crucial inputs to the INL NGNP/VHTR Methods Research and Development project. The second year of this three-year project (FY-08 to FY-10) was focused on (a) the analytical, CFD, and experimental study of air ingress caused by density-driven, stratified, countercurrent flow; (b) advanced graphite oxidation experiments and modeling; (c) experimental study of burn-off in the core bottom structures, (d) implementation of advanced graphite oxidation models into the GAMMA code, and (f) air ingress and oxidation mitigation analyses of the whole air-ingress scenario.

  6. Woven graphite fiber structures for use in ultra-light weigth heat exchangers

    SciTech Connect (OSTI)

    Hemrick, James Gordon [ORNL; Lara-Curzio, Edgar [ORNL; Loveland, Erick R [ORNL; Sharp, Keith W [ORNL; Schartow, Robert [3TEX Incorporated

    2011-01-01T23:59:59.000Z

    As part of U.S. Department of Energy efforts to find novel approaches for thermal management and heat recovery, work was undertaken at Oak Ridge National Laboratory (ORNL) to investigate the use of graphite-based materials for heat exchanger and thermal management devices. From this effort, lightweight, robust woven graphite-fiber structures were developed which provide high conductivity paths along the direction of the graphite fibers. These structures were produced and characterized for air permeability/pressure drop and thermal (heat transfer) performance. Results have been shown to be favorable for using such structures in ultra-light weight heat exchanger applications such as vehicle radiators or other areas where light weight, compact, conformable heat transfer devices are needed.

  7. Phase transformations of nano-sized cubic boron nitride to white graphene and white graphite

    SciTech Connect (OSTI)

    Dang, Hongli; Liu, Yingdi; Xue, Wenhua; Anderson, Ryan S.; Sewell, Cody R. [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Xue, Sha; Crunkleton, Daniel W. [Department of Chemical Engineering, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Shen, Yaogen [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon (Hong Kong); Wang, Sanwu, E-mail: sanwu-wang@utulsa.edu [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States)

    2014-03-03T23:59:59.000Z

    We report quantum-mechanical investigations that predict the formation of white graphene and nano-sized white graphite from the first-order phase transformations of nano-sized boron nitride thin-films. The phase transformations from the nano-sized diamond-like structure, when the thickness d?>?1.4?nm, to the energetically more stable nano-sized white graphite involve low activation energies of less than 1.0?eV. On the other hand, the diamond-like structure transforms spontaneously to white graphite when d???1.4?nm. In particular, the two-dimensional structure with single-layer boron nitride, the so-called white graphene, could be formed as a result of such transformation.

  8. A one-group parametric sensitivity analysis for the graphite isotope ratio method and other related techniques using ORIGEN 2.2 

    E-Print Network [OSTI]

    Chesson, Kristin Elaine

    2009-06-02T23:59:59.000Z

    Several methods have been developed previously for estimating cumulative energy production and plutonium production from graphite-moderated reactors. The Graphite Isotope Ratio Method (GIRM) is one well-known technique. This method is based...

  9. Electrochemical and structural characterization of ordered graphite electrodes

    SciTech Connect (OSTI)

    McDermott, M.T.

    1993-01-01T23:59:59.000Z

    Highly oriented pyrolytic graphite (HOPG) was utilized to examine the structure/reactivity relationships for carbon electrodes in a well-defined matter. The basal plane of HOPG is ideal for this type of study due to its well-ordered surface structure. The electrochemical reactivity of basal plane HOPG was determined in terms of adsorption of anthraquinone 2,6-desulfonate ([Gamma][sub 2,6-AQDS]), the heterogeneous electron transfer rate constant of the ferro/ferricyanide redox couple (k[degrees] for Fe(CN)[sup [minus]3/[minus]4][sub 6]) and electrode capacitance (C[degrees]). [Gamma][sub 2,6-AQDS] tracks defects at basal plane HOPG electrodes indicating that the adsorption of 2,6-AQDS is a good marker for defects on the surface of basal plane HOPG. When measured on the same basal plane surface, k[degrees] for Fe(CN)[sup [minus]3/[minus]4][sub 6] and C[degrees] correlate with [Gamma][sub 2,6-AQDS] indicating that all three electrochemical observables are controlled by the same surface variables. This illustrates the importance of surface defects on electrochemical activity at basal plane HOPG electrodes. The correlation between k[degrees] for Fe(CN)[sup [minus]3/[minus]4][sub 6], C[degrees] and [Gamma][sub 2,6-AQDS] enabled the evaluation of these parameters at near-perfect basal plane. The data indicate that basal plane HOPG exhibits anomalously low electrochemical reactivity. An investigation of basal plane HOPG electrodes with scanning tunneling microscopy (STM) revealed that defects, in the form of cleavage steps, cover 1% of the surface for the HOPG sample studied. Atomic scale STM images of step edges revealed that structural defects induce an electronic perturbation of the surface which occupies a significant area near the defect. [Gamma][sub 2,6-AQDS], k[degrees] for Fe(CN)[sup [minus]3/[minus]4][sub 6] and C[degrees] are influenced not only by the structural defect but also by the defect induced electronic perturbation.

  10. Network Modeling of Arctic Melt Ponds Meenakshi Barjatiaa

    E-Print Network [OSTI]

    Golden, Kenneth M.

    . In late spring and summer, the albedo of the ice pack is determined primarily by melt ponds that form­albedo feedback [7], and has played a significant role in the decline of the summer Arctic ice pack [8]. Sea ice precipitous losses of summer Arctic sea ice have outpaced the pro- jections of most climate models. Efforts

  11. The effect of pressure upon the melting transition of polyethylene

    E-Print Network [OSTI]

    Mroz, George Joseph

    1961-01-01T23:59:59.000Z

    THE EFFECT OF PRESSURE UPON THE MELTING TRANSITION OF POLYETHYLENE o m vS n Z 8 i c6 C 0 A Thesis By George Joseph Nros Approved as to style and content by: C a rman o Comm ttee (Head of Department) August 1961 ACKNOWLEDGEMENT...

  12. Buoyant melting instabilities beneath extending lithosphere: 1. Numerical models

    E-Print Network [OSTI]

    Tackley, Paul J.

    Buoyant melting instabilities beneath extending lithosphere: 1. Numerical models John W. Hernlund,1,2 Paul J. Tackley,1,3 and David J. Stevenson4 Received 18 November 2006; revised 18 October 2007 diffusely extending lithosphere is studied using numerical convection models covering a wide range

  13. Feasibility of re-melting NORM-contaminated scrap metal

    SciTech Connect (OSTI)

    Winters, S. J.; Smith, K. P.

    1999-10-26T23:59:59.000Z

    Naturally occurring radioactive materials (NORM) sometimes accumulate inside pieces of equipment associated with oil and gas production and processing activities. Typically, the NORM accumulates when radium that is present in solution in produced water precipitates out in scale and sludge deposits. Scrap equipment containing residual quantities of these NORM-bearing scales and sludges can present a waste management problem if the radium concentrations exceed regulatory limits or activate the alarms on radiation screening devices installed at most scrap metal recycling facilities. Although NORM-contaminated scrap metal currently is not disposed of by re-melting, this form of recycling could present a viable disposition option for this waste stream. Studies indicate that re-melting NORM-contaminated scrap metal is a viable recycling option from a risk-based perspective. However, a myriad of economic, regulatory, and policy issues have caused the recyclers to turn away virtually all radioactive scrap metal. Until these issues can be resolved, re-melting of the petroleum industry's NORM-impacted scrap metal is unlikely to be a widespread practice. This paper summarizes the issues associated with re-melting radioactive scrap so that the petroleum industry and its regulators will understand the obstacles. This paper was prepared as part of a report being prepared by the Interstate Oil and Gas Compact Commission's NORM Subcommittee.

  14. Laser thermoelastic generation in metals above the melt threshold

    SciTech Connect (OSTI)

    Every, A. G. [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa)] [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa); Utegulov, Z. N. [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan)] [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan); Veres, I. A. [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)] [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)

    2013-11-28T23:59:59.000Z

    An approach is presented for calculating thermoelastic generation of ultrasound in a metal plate exposed to nanosecond pulsed laser heating, sufficient to cause melting but not ablation. Detailed consideration is given to the spatial and temporal profiles of the laser pulse, penetration of the laser beam into the sample, the appearance and subsequent growth and then contraction of the melt pool, and the time dependent thermal conduction in the melt and surrounding solid throughout. The excitation of the ultrasound takes place during and shortly after the laser pulse and occurs predominantly within the thermal diffusion length of a micron or so beneath the surface. It is shown how, because of this, the output of the thermal simulations can be expressed as axially symmetric transient radial and normal surface force distributions. The epicentral displacement response to these force distributions is obtained by two methods, the one based on the elastodynamic Green's functions for plate geometry determined by the Cagniard generalized ray method and the other using a finite element numerical method. The two approaches are in very close agreement. Numerical simulations are reported on the epicentral displacement response of a 3.12 mm thick tungsten plate irradiated with a 4 ns pulsed laser beam with Gaussian spatial profile, at intensities below and above the melt threshold.

  15. Seasonal glacier melt contribution to streamflow Neil Schaner

    E-Print Network [OSTI]

    Washington at Seattle, University of

    1 Seasonal glacier melt contribution to streamflow Neil Schaner Department of Civil of Washington Seattle, WA 98195 dennisl@u.washington.edu #12;2 Ongoing and projected future changes in glacier. However, the current magnitude of glacier contributions to river runoff is not well known, nor

  16. Glacier melt contribution to streamflow1 Neil Schaner1

    E-Print Network [OSTI]

    Washington at Seattle, University of

    1 Glacier melt contribution to streamflow1 Neil Schaner1 , Nathalie Voisin2 , Bart Nijssen1 12 * Corresponding author13 Abstract. Ongoing and projected future changes in glacier extent and water storage14 globally have led to concerns about the implications for water supplies. Glacier15

  17. Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive

    E-Print Network [OSTI]

    Williamson, Craig E.

    Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen J A S M I N E E . S A R received May 26, 2010. Accepted May 28, 2010. Alpine glaciers have receded substantially over the last. Our results demonstrate that the presence of glaciers on alpine watersheds more strongly influences NO

  18. THE CONTRIBUTION OF GREENLAND ICE SHEET MELTING TO

    E-Print Network [OSTI]

    THE CONTRIBUTION OF GREENLAND ICE SHEET MELTING TO GLOBAL SEA-LEVEL CHANGE Conor Mc three major sources, the Greenland ice sheet, Antarctica, and other eustatic components. Each has its own predictable spatial signal, and particular attention was paid to the Greenland ice sheet, given

  19. Potential for tunneling based on rock and soil melting. Abstracts

    SciTech Connect (OSTI)

    Rowley, J.C.

    1985-01-01T23:59:59.000Z

    The rock-melting drill was invented at Los Alamos Scientific Laboratory in 1960. Electrically heated, laboratory-scale drills were subsequently shown to penetrate igneous rocks at usefully high rates, with moderate power consumptions. The development of compact nuclear reactors and of heat pipes now makes possible the extension of this technology to much larger melting penetrators, potentially capable of producing holes up to several meters in diameter and several tens of kilometers long or deep. Development of a rapid, versatile, economical method of boring large, long shafts and tunnels offers solutions to many of man's most urgent ecological, scientific, raw-materials, and energy-supply problems. A melting method appears to be the most promising and flexible means of producing such holes. It is relatively insensitive to the composition, hardness, structure, and temperature of the rock, and offers the possibilities of producing self-supporting, glass-lined holes in almost any formation and (using a technique called lithofracturing) of eliminating the debris-removal problem by forcing molten rock into cracks created in the bore wall. Large rock-melting penetrators, called Electric Subterrenes or Nuclear Subterrenes according to the energy source used, are discussed in this report, together with problems anticipated in their development. It is concluded that this development is within the grasp of present technology.

  20. Beryllium and Graphite Neutron Total Cross-Section Measurements from 0.4 to 20 MeV

    E-Print Network [OSTI]

    Danon, Yaron

    Beryllium and Graphite Neutron Total Cross-Section Measurements from 0.4 to 20 MeV M. J. Rapp,* Y of the neutron total cross section of natural beryllium and carbon (graphite) in the energy range of 0.4 to 20 Me a verification of the accuracy in the measurement and analytical methods used. The measurements of beryllium

  1. Latex and two-roll mill processing of thermally-exfoliated graphite oxide/natural rubber nanocomposites

    E-Print Network [OSTI]

    Latex and two-roll mill processing of thermally-exfoliated graphite oxide/natural rubber t Thermally-exfoliated graphite oxide (TEGO) is a graphene-based material that has been previously shown to graphene-based materials [4]. GO can be exfoliated in water into single-layer graphene oxide platelets

  2. STUDY OF GRAPHITE TARGETS INTERACTING WITH THE 24 GeV PROTON BEAM OF THE BNL MUON TARGET EXPERIMENT*

    E-Print Network [OSTI]

    McDonald, Kirk

    experiment, graphite and carbon-carbon composite targets were exposed to the AGS beam and their response materials for the future muon collider/neutrino factory carbon-based solid targets have been considered for the experiment are ATJ graphite and the anisotropic carbon-carbon composite. Each target consists of a pair of 16

  3. Improved Lithium Ion Behavior Properties of TiO2@Graphitic-like Carbon Core@Shell Nanostructure

    E-Print Network [OSTI]

    Cao, Guozhong

    Improved Lithium Ion Behavior Properties of TiO2@Graphitic-like Carbon Core@Shell Nanostructure Min Intercalation Electrochemistry Capacitance Lithium Ion batteries A B S T R A C T We demonstrate TiO2@graphitic on the electrode surface and enhanced lithium ion intercalation, leading to lower charge transfer resistance

  4. A Simplified Electrochemical and Thermal Aging Model of LiFePO4-Graphite Li-ion Batteries

    E-Print Network [OSTI]

    1 A Simplified Electrochemical and Thermal Aging Model of LiFePO4-Graphite Li-ion Batteries: Power of a commercial LiFePO4-graphite Li-ion battery. Compared to the isothermal reference, the mechanism of porosity;2 Due to their high power and energy densities, Li-ion technologies are the leading battery systems

  5. Simplified Electrochemical and Thermal Model of LiFePO4-Graphite Li-Ion Batteries for Fast Charge Applications

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Simplified Electrochemical and Thermal Model of LiFePO4- Graphite Li-Ion Batteries for Fast Charge, a simplified electrochemical and thermal model of LiFePO4-graphite based Li-ion batteries is developed for battery management system (BMS) applications and comprehensive aging investigations. Based on a modified

  6. Comparison of beryllium oxide and pyrolytic graphite crucibles for boron doped silicon epitaxy

    SciTech Connect (OSTI)

    Ali, Dyan; Richardson, Christopher J. K. [Laboratory for Physical Sciences, University of Maryland, College Park, Maryland 20740 (United States)

    2012-11-15T23:59:59.000Z

    This article reports on the comparison of beryllium oxide and pyrolytic graphite as crucible liners in a high-temperature effusion cell used for boron doping in silicon grown by molecular beam epitaxy. Secondary ion mass spectroscopy analysis indicates decomposition of the beryllium oxide liner, leading to significant incorporation of beryllium and oxygen in the grown films. The resulting films are of poor crystal quality with rough surfaces and broad x-ray diffraction peaks. Alternatively, the use of pyrolytic graphite crucible liners results in higher quality films.

  7. Analysis of the effect of matrix degradation on fatigue behavior of a graphite/epoxy laminate

    E-Print Network [OSTI]

    Arenburg, Robert Thomas

    1982-01-01T23:59:59.000Z

    ANALYSIS OF THE EFFECT OF MATRIX DEGRADATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Major Subject: Civil Engineering ANALYSiS OF THE EFFECT OF MATRIX DEGRAOATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Approved as to style and content by: (Chairman...

  8. Analysis of the effect of matrix degradation on fatigue behavior of a graphite/epoxy laminate 

    E-Print Network [OSTI]

    Arenburg, Robert Thomas

    1982-01-01T23:59:59.000Z

    ANALYSIS OF THE EFFECT OF MATRIX DEGRADATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Major Subject: Civil Engineering ANALYSiS OF THE EFFECT OF MATRIX DEGRAOATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Approved as to style and content by: (Chairman...

  9. Hygrothermal effects in an anti-symmetric cross-ply graphite/epoxy material 

    E-Print Network [OSTI]

    Jackson, Steven Paul

    1984-01-01T23:59:59.000Z

    HYGROTHERMAL EFFECTS IN AN ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY MATERIAL A Thesis STEVEN PAUL JACKSON Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SC...'IENCE May 1984 Major Subject: Aerospace Engineering HYGROTHERMAL ~S IN AN ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY LAMINATE A Thesis STEVE? PAUL JACKSON Approved as to style and content by: (Y. eitsman, Charrman) (W. L. Bradley, M (W. E. Haisler...

  10. Mode I transverse cracking in an epoxy and a graphite fiber reinforced epoxy 

    E-Print Network [OSTI]

    Williams, David Robert

    1981-01-01T23:59:59.000Z

    iNIODE I TRAiUSVERSE CRACKING IN AN EPOXY AUD A GRAPHITE FIBER REINFORCED EPOXY A Thesis by DAVID ROBERT l7ILLIAMS Submitted to the Graduate College of Texas A6M University ir. partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1981 Major Subject: Interdisciplinary Engineering NODE I TRAiUSVERSE CRACKING IN AN EPOXY AiND A GRAPHITE FIBER REINFORCED EPOXY A Thesis by DAVID ROBERT WILLIAMS Approved as to style and content by: (Walter L. Bradley, Char man...

  11. Near-field thermal radiation between hyperbolic metamaterials: Graphite and carbon nanotubes

    SciTech Connect (OSTI)

    Liu, X. L.; Zhang, R. Z.; Zhang, Z. M., E-mail: zhuomin.zhang@me.gatech.edu [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2013-11-18T23:59:59.000Z

    The near-field radiative heat transfer for two hyperbolic metamaterials, namely, graphite and vertically aligned carbon nanotubes (CNTs), is investigated. Graphite is a naturally existing uniaxial medium, while CNT arrays can be modeled as an effective anisotropic medium. Different hyperbolic modes can be separately supported by these materials in certain infrared regions, resulting in a strong enhancement in near-field heat transfer. It is predicted that the heat flux between two CNT arrays can exceed that between SiC plates at any vacuum gap distance and is about 10 times higher with a 10?nm gap.

  12. Decontamination of metals by melt refining/slagging. An annotated bibliography: Update on stainless steel and steel

    SciTech Connect (OSTI)

    Worchester, S.A.; Twidwell, L.G.; Paolini, D.J.; Weldon, T.A. [Montana Tech of the Univ., of Montana (United States); Mizia, R.E. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

    1995-01-01T23:59:59.000Z

    The following presentation is an update to a previous annotation, i.e., WINCO-1138. The literature search and annotated review covers all metals used in the nuclear industries but the emphasis of this update is directed toward work performed on mild steels. As the number of nuclear installations undergoing decontamination and decommissioning (D&D) increases, current radioactive waste storage space is consumed and establishment of new waste storage areas becomes increasingly difficult, the problem of handling and storing radioactive scrap metal (RSM) gains increasing importance in the DOE Environmental Restoration and Waste Management Program. To alleviate present and future waste problems, Lockheed Idaho Technologies Co (LITCO) is managing a program for the recycling of RSM for beneficial use within the DOE complex. As part of that effort, Montana Tech has been awarded a contract to help optimize melting and refining technology for the recycling of stainless steel RSM. The scope of the Montana Tech program includes a literature survey, a decontaminating slag design study, small wide melting studies to determine optimum slag compositions for removal of radioactive contaminant surrogates, analysis of preferred melting techniques, and coordination of large scale melting demonstrations (100--2,000 lbs) to be conducted at selected facilities. The program will support recycling and decontaminating stainless steel RSM for use in waste canisters for Idaho Waste Immobilization Facility densified high level waste and Pit 9/RWMC boxes. This report is the result of the literature search conducted to establish a basis for experimental melt/slag program development. The program plan will be jointly developed by Montana Tech and LITCO.

  13. Analysis of volumetric changes through melting using a dilatometer

    SciTech Connect (OSTI)

    Frankel, Jay I [ORNL; Porter, Wallace D [ORNL; Sabau, Adrian S [ORNL

    2005-01-01T23:59:59.000Z

    A conventional push-rod dilatometer is modified in order to accurately correlate the measured density to the predicted sample temperature of alloys in the phase-change regime. This new configuration makes use of a standard furnace assembly; however, the specimen is now symmetrically encased in a well-instrumented, graphite cylindrical shell. The combination of system geometry and high-conductivity sample holder material promotes the development of a simplified heat transfer model. The solution of this model properly correlates the measured density to that of the actual sample temperature based on using remote, sample-holder temperature measurements. Preliminary results using aluminum A356 provide insight into the proposed configuration.

  14. Application of a Barrier Filter at a High Purity Synthetic Graphite Plant, CRADA 99-F035, Final Report

    SciTech Connect (OSTI)

    National Energy Technology Laboratory

    2000-08-31T23:59:59.000Z

    Superior Graphite Company and the US Department of Energy have entered into a Cooperative Research and Development Agreement (CRADA) to study the application of ceramic barrier filters at its Hopkinsville, Kentucky graphite plant. Superior Graphite Company is a worldwide leader in the application of advanced thermal processing technology to produce high purity graphite and carbons. The objective of the CRADA is to determine the technical and economic feasibility of incorporating the use of high-temperature filters to improve the performance of the offgas treatment system. A conceptual design was developed incorporating the ceramic filters into the offgas treatment system to be used for the development of a capital cost estimate and economic feasibility assessment of this technology for improving particulate removal. This CRADA is a joint effort of Superior Graphite Company, Parsons Infrastructure and Technology Group, and the National Energy Technology Laboratory (NETL) of the US Department of Energy (DOE).

  15. Geek-Up: K East Reactor Demolition, Retrograde Melting and Cloud...

    Broader source: Energy.gov (indexed) [DOE]

    Geek-Up: K East Reactor Demolition, Retrograde Melting and Cloud Pattern Tracking Geek-Up: K East Reactor Demolition, Retrograde Melting and Cloud Pattern Tracking August 13, 2010...

  16. CATALYTIC LIQUEFACTION BY ZINC CHLORIDE MELTS AT PRE-PYROLYSIS TEMPERATURE

    E-Print Network [OSTI]

    Vermeulen, T.

    2012-01-01T23:59:59.000Z

    stream. Plug flow of melt/coal slurry is projected, becauseviscosity of the melt/coal slurry would always be less thanscheme, raw coal is blended into a slurry with ZnCl2/CH30H

  17. PHYSICAL REVIEW B 84, 092102 (2011) Melting temperature of tungsten from two ab initio approaches

    E-Print Network [OSTI]

    Alfè, Dario

    2011-01-01T23:59:59.000Z

    PHYSICAL REVIEW B 84, 092102 (2011) Melting temperature of tungsten from two ab initio approaches L the melting temperature of tungsten by two ab initio approaches. The first approach can be divided into two

  18. Shear wave attenuation and dispersion in melt-bearing olivine polycrystals

    E-Print Network [OSTI]

    interpretation and seismological implications Ulrich H. Faul, John D. Fitz Gerald, and Ian Jackson Research: seismic wave attenuation, olivine, partial melting, grain boundary sliding, grain boundary structure and dispersion in melt-bearing olivine polycrystals: 2. Microstructural interpretation and seismological

  19. Crustal structure beneath the gravity lineations in the Gravity Lineations, Intraplate Melting, Petrologic and Seismic Expedition

    E-Print Network [OSTI]

    Webb, Spahr C.

    , Petrologic and Seismic Expedition (GLIMPSE) study area from seismic refraction data R. Chadwick Holmes,1, Intraplate Melting, Petrologic and Seismic Expedition (GLIMPSE) experiment investigated the velocity in the Gravity Lineations, Intraplate Melting, Petrologic and Seismic Expedition (GLIMPSE) study area from

  20. Effect of grain size on the melting point of confined thin aluminum films

    SciTech Connect (OSTI)

    Wejrzanowski, Tomasz; Lewandowska, Malgorzata; Sikorski, Krzysztof; Kurzydlowski, Krzysztof J. [Materials Design Division, Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw (Poland)

    2014-10-28T23:59:59.000Z

    The melting of aluminum thin film was studied by a molecular dynamics (MD) simulation technique. The effect of the grain size and type of confinement was investigated for aluminum film with a constant thickness of 4?nm. The results show that coherent intercrystalline interface suppress the transition of solid aluminum into liquid, while free-surface gives melting point depression. The mechanism of melting of polycrystalline aluminum thin film was investigated. It was found that melting starts at grain boundaries and propagates to grain interiors. The melting point was calculated from the Lindemann index criterion, taking into account only atoms near to grain boundaries. This made it possible to extend melting point calculations to bigger grains, which require a long time (in the MD scale) to be fully molten. The results show that 4?nm thick film of aluminum melts at a temperature lower than the melting point of bulk aluminum (933?K) only when the grain size is reduced to 6?nm.

  1. The SF6 monolayer on graphite by X-ray diffraction C. Marti, T. Ceva, B. Croset, C. De Beauvais and A. Thomy (*)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1517 The SF6 monolayer on graphite by X-ray diffraction C. Marti, T. Ceva, B. Croset, C. De) Résumé. 2014 La structure du film de SF6 adsorbé sur graphite a été étudiée entre 35 et 180 K par du cristal 3D, ce qui explique le mouillage imparfait du graphite par SF6. Dans le domaine où la

  2. Trace element partitioning during high-P partial melting and melt-rock interaction; an example from northern Fiordland,

    E-Print Network [OSTI]

    Daczko, Nathan

    reaction zones. New data acquired using a Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LA to sites of partial melting in the dioritic gneiss. Key words: garnet granulite; Laser Ablation Inductively-clinopyroxene assemblage. In this paper, we present geochemical data obtained by an in-situ Laser Ablation Inductively

  3. Adiabat_1ph: A new public front-end to the MELTS, pMELTS, and pHMELTS models

    E-Print Network [OSTI]

    Asimow, Paul D.

    and Petrology: Geochemical modeling (1009, 8410); 3611 Mineralogy and Petrology: Thermodynamics (0766, 1011, 8411); 3612 Mineralogy and Petrology: Reactions and phase equilibria (1012, 8412); 3618 Mineralogy and Petrology: Magma chamber processes (1036); 3619 Mineralogy and Petrology: Magma genesis and partial melting

  4. METHODOLOGICAL RE-EVALUATION OF THE ELECTRICAL CONDUCTIVITY OF SILICATE MELTS

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Revised ms METHODOLOGICAL RE-EVALUATION OF THE ELECTRICAL CONDUCTIVITY OF SILICATE MELTS A in laboratory on silicate melts are used to interpret magnetotelluric anomalies. On the basis of two- and four to small chemical and physical changes, it represents a subtle probe for studying silicate melts properties

  5. Blast from the Past: Melting Glaciers as a Relevant Source for

    E-Print Network [OSTI]

    Wehrli, Bernhard

    Blast from the Past: Melting Glaciers as a Relevant Source for Persistent Organic Pollutants C H R, 2009. Accepted August 31, 2009. In this study, the hypothesis that melting Alpine glaciers may organic chemicals from melting Alpine glaciers. Considering ongoing global warming and accelerated massive

  6. A NEW METHOD FOR MELT DETECTION ON ANTARCTIC ICE-SHELVES AND SCATTEROMETER CALIBRATION

    E-Print Network [OSTI]

    Long, David G.

    A NEW METHOD FOR MELT DETECTION ON ANTARCTIC ICE-SHELVES AND SCATTEROMETER CALIBRATION VERIFICATION of Engineering and Technology #12;ABSTRACT A NEW METHOD FOR MELT DETECTION ON ANTARCTIC ICE-SHELVES to determine periods of surface melt and freeze in the Antarctic ice-shelves. The normalized radar backscatter

  7. Ion fractionation and percolation in ice cores with seasonal melting John C. Moore*, Aslak Grinsted **

    E-Print Network [OSTI]

    Moore, John

    and with the type of data that was expected to come from ice caps with seasonal melt. The objective of this paperIon fractionation and percolation in ice cores with seasonal melting John C. Moore*, Aslak Grinsted that suffer limited seasonal melting. We show that the impact in the case of at least one Svalbard ice core

  8. Basal melting of snow on early Mars: A possible origin of some valley Michael H. Carr

    E-Print Network [OSTI]

    Head III, James William

    that valley networks could have formed as a result of basal melting of thick snow and ice deposits. Depending in part by basal melting of the south polar cap [Clifford, 1987], this cannot be the only mechanismBasal melting of snow on early Mars: A possible origin of some valley networks Michael H. Carr U. S

  9. Melting of small Arctic ice caps observed from ERS scatterometer time series

    E-Print Network [OSTI]

    Smith, Laurence C.

    Melting of small Arctic ice caps observed from ERS scatterometer time series Laurence C. Smith,1 of melt onset can be observed over small ice caps, as well as the major ice sheets and multi-year sea ice for 14 small Arctic ice caps from 1992­2000. Interannual and regional variability in the timing of melt

  10. CO2 isotopes as tracers of firn air diffusion and age in an Arctic ice cap with summer melting, Devon Island, Canada

    E-Print Network [OSTI]

    Chappellaz, Jérôme

    and the effects of summer melting. The 14 CO2 profile from the permeable firn includes the 1963 thermonuclear peak, and accumulation rates were calibrated with the depth of the 1963 thermonuclear 3 H peak. The average ages for CO2 and the ice matrix. Calibrated with the 1963 peak for thermonuclear 14 CO2, a 21.2-year reaction halftime

  11. The probability of Mark-I containment failure by melt-attack of the liner

    SciTech Connect (OSTI)

    Theofanous, T.G.; Yan, H. [California Univ., Santa Barbara, CA (United States). Dept. of Chemical and Nuclear Engineering; Podowski, M.Z. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Nuclear Engineering and Engineering Physics] [and others

    1993-11-01T23:59:59.000Z

    This report is a followup to the work presented in NUREG/CR-5423 addressing early failure of a BWR Mark I containment by melt attack of the liner, and it constitutes a part of the implementation of the Risk-Oriented Accident Analysis Methodology (ROAAM) employed therein. In particular, it expands the quantification to include four independent evaluations carried out at Rensselaer Polytechnic Institute, Argonne National Laboratories, Sandia National Laboratories and ANATECH, Inc. on the various portions of the phenomenology involved. These independent evaluations are included here as Parts II through V. The results, and their integration in Part I, demonstrate the substantial synergism and convergence necessary to recognize that the issue has been resolved.

  12. Jaszczak et al. 1 MICRO-AND NANO-SCALE GRAPHITE CONES AND TUBES FROM HACKMAN

    E-Print Network [OSTI]

    Jaszczak, John A.

    of micro- and nano-scale RGS. The largest of the RGS are hollow scrolls, with the c-axis predominantly at the micro- and nano-scales. The nano-scale cones tend not to be hollow and may have a cone-helix structureJaszczak et al. 1 MICRO- AND NANO-SCALE GRAPHITE CONES AND TUBES FROM HACKMAN VALLEY, KOLA

  13. MTHODE D'OSCILLATION DANS LA PILE, APPLIQUE A LA COMPARAISON D'CHANTILLONS DE GRAPHITE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    784. MÉTHODE D'OSCILLATION DANS LA PILE, APPLIQUÉE A LA COMPARAISON D'ÉCHANTILLONS DE GRAPHITE Par aux Roses. Sommaire. 2014 On fait osciller lentement dans le réflecteur d'une pile un échantillon de'une pile de l'oscillation d'un absorbeur a été étudié théoriquement par A. M. Weinberg et H. C. Schweinler

  14. Graphite and Hexagonal Boron-Nitride have the Same Interlayer Distance. Why?

    E-Print Network [OSTI]

    Hod, Oded

    -8 In recent years, the most prominent member of the family of layered materials has been graphene,9-12 which serves as a building block for few-layered graphene and graphite as well as for single- and multi the material into a semimetal. The main factors expected to dominate graphene interlayer binding

  15. Low-Temperature Phase Transformation from Graphite to sp3 Orthorhombic Carbon

    E-Print Network [OSTI]

    Wang, Wei Hua

    Low-Temperature Phase Transformation from Graphite to sp3 Orthorhombic Carbon Jian-Tao Wang,1, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2 Department of Physics and High February 2011) We identify by ab initio calculations an orthorhombic carbon polymorph in Pnma symmetry

  16. Laser-excited atomic fluorescence spectrometry in a graphite furnace with an

    E-Print Network [OSTI]

    Michel, Robert G.

    must provide high peak energy above sequentially with the analysis time determined primarilyLaser-excited atomic fluorescence spectrometry in a graphite furnace with an optical parametric for electrothermal atomic excited atomic ¯ uorescence spectrometry (LEAFS ) in a absorption spectrometry (ETAAS

  17. THE SYNTHESIS AND CHARACTERIZATION OF GRAPHITE-METAL FLUORIDE INTERCALATION COMPOUNDS

    E-Print Network [OSTI]

    McQuillan, Barry William

    2014-01-01T23:59:59.000Z

    inside graphite, except for UF6 which has ~s.1 A. The -6H 0that the lattice energy U(NO+UF6(c)) =- 152 kcal mole- 1 • Asince PtF6 is smaller than UF6, the electron affinity of PtF

  18. Electrode material comprising graphene-composite materials in a graphite network

    SciTech Connect (OSTI)

    Kung, Harold H.; Lee, Jung K.

    2014-07-15T23:59:59.000Z

    A durable electrode material suitable for use in Li ion batteries is provided. The material is comprised of a continuous network of graphite regions integrated with, and in good electrical contact with a composite comprising graphene sheets and an electrically active material, such as silicon, wherein the electrically active material is dispersed between, and supported by, the graphene sheets.

  19. Photoexfoliation of Graphene from Graphite: An Ab Initio Study Yoshiyuki Miyamoto,1

    E-Print Network [OSTI]

    exfoliation process follows exposure to femtosecond laser pulses with a wavelength of 800 nm and the full and intensity speed up the exfoliation and cause transient contraction in subsurface layers. Photoexfoliation] or chemical [3­7] exfoliation of graphite, or may form by annealing SiC single crystals [8], or by chemical

  20. Self-assembly of long chain alkanes and their derivatives on graphite Teng Yang,1

    E-Print Network [OSTI]

    , University of New Hampshire, Durham, New Hampshire 03824, USA Received 5 November 2007; accepted 16 January the energetic origin of the domain formation observed in the STM images. Our results for the hierarchy­8 Although many patterns have been reported even for alkane films on graphite, the energetic grounds

  1. Layering and orientational ordering of propane on graphite: An experimental and simulation study

    E-Print Network [OSTI]

    Borguet, Eric

    Layering and orientational ordering of propane on graphite: An experimental and simulation study 2002; accepted 30 July 2002 We report the results of an experimental and theoretical study of propane and experiments show that propane adsorbs in a layer-by-layer fashion and exhibits continuous growth beyond

  2. On the Origin of High-Density Graphite Grains from the Murchison Meteorite

    E-Print Network [OSTI]

    of the mineral types that carry isotopically anomalous noble gases [7]. Graphite grains extracted from) stars. s-Process Kr in KFC1 is best explained with 5M8 stars of solar and/or half-solar metallicities. Keywords: Presolar Grains; Dust; Meteorites; AGB stars, s-process. PACS: 26.20.Fj; 26.20.Kn; 91.65.Dt; 96

  3. Influence of the solvent on the stability of bis(terpyridine) structures1 on graphite2

    E-Print Network [OSTI]

    Ulm, Universität

    . Although electronic structure calculations based on48 density functional theory can reproduce Influence of the solvent on the stability of bis(terpyridine) structures1 on graphite2 Daniela molecular dynamics simulations. As a model system, the sol-9 vation of a bis(terpyridine) (BTP) isomer

  4. Electropolymerization kinetics of pyrrole in aqueous solution on graphite felt electrodes

    E-Print Network [OSTI]

    Otero, Toribio Fernández

    Electropolymerization kinetics of pyrrole in aqueous solution on graphite felt electrodes I. depends on the synthesis conditions, such as the nature of the solvent, the electro- synthesis method®c properties, the synthesis conditions play a vital role in the performance of the material. In this work, we

  5. Graphitic Phase of NaCl. Bulk Properties and Nanoscale Stability Alexander G. Kvashnin,,,

    E-Print Network [OSTI]

    Tománek, David

    Graphitic Phase of NaCl. Bulk Properties and Nanoscale Stability Alexander G. Kvashnin,,,§ Pavel B approach to evaluate the stability and physical properties of the nanometer-thickness NaCl layered films and found that the rock salt films with a (111) surface become unstable with thickness below 1 nm

  6. Graphite Waste Tank Cleanup and Decontamination under the Marcoule UP1 D and D Program - 13166

    SciTech Connect (OSTI)

    Thomasset, Philippe [AREVA D and D BU, Marcoule (France)] [AREVA D and D BU, Marcoule (France); Chabeuf, Jean-Michel [AREVA D and D BU, La Hague (France)] [AREVA D and D BU, La Hague (France); Thiebaut, Valerie [CEA/DEN/DAPD/CPUP, Marcoule (France)] [CEA/DEN/DAPD/CPUP, Marcoule (France); Chambon, Frederic [AREVA FEDERAL SERVICES, Columbia, MD (United States)] [AREVA FEDERAL SERVICES, Columbia, MD (United States)

    2013-07-01T23:59:59.000Z

    The UP1 plant in Marcoule reprocessed nearly 20,000 tons of used natural uranium gas cooled reactor fuel coming from the first generation of civil nuclear reactors in France. During more than 40 years, the decladding operations produced thousands of tons of processed waste, mainly magnesium and graphite fragments. In the absence of a French repository for the graphite waste, the graphite sludge content of the storage pits had to be retrieved and transferred into a newer and safer pit. After an extensive R and D program, the equipment and process necessary for retrieval operations were designed, built and tested. The innovative process is mainly based on the use of two pumps (one to capture and the other one to transfer the sludge) working one after the other and a robotic arm mounted on a telescopic mast. A dedicated process was also set up for the removal of the biggest fragments. The retrieval of the most irradiating fragments was a challenge. Today, the first pit is totally empty and its stainless steel walls have been decontaminated using gels. In the second pit, the sludge retrieval and transfer operations have been almost completed. Most of the non-pumpable graphite fragments has been removed and transferred to a new storage pit. After more than 6 years of operations in sludge retrieval, a lot of experience was acquired from which important 'lessons learned' could be shared. (authors)

  7. Polymer-Graphite Nanocomposites: Effective Dispersion and Major Property Enhancement via

    E-Print Network [OSTI]

    Polymer-Graphite Nanocomposites: Effective Dispersion and Major Property Enhancement via SolidVed NoVember 2, 2007 Introduction. Polymer nanocomposites are of scientific and commercial interest-hybridized carbon layers termed "graphene sheets" are isolated or in "paper" form.20-23 Chemi- cally similar

  8. Synthesis, characterization, and magnetic properties of room-temperature nanofluid ferromagnetic graphite

    E-Print Network [OSTI]

    de Lima, Oscar Ferreira

    Synthesis, characterization, and magnetic properties of room-temperature nanofluid ferromagnetic characterization, and physical properties of nanofluid magnetic graphite NFMG obtained from the previously. © 2009 American Institute of Physics. doi:10.1063/1.3265945 Nanofluids can be defined as fluids

  9. BrickandMortar SelfAssembly Approach to Graphitic Mesoporous...

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

    percolation. 11 Carbon materials that are used for applications such as supercapacitor electrodes include activated carbon, carbide derived carbon, templated carbon, ...

  10. Vacancies in Al after pulsed electron beam melting

    SciTech Connect (OSTI)

    Follstaedt, D.M.; Wampler, W.R.

    1981-02-01T23:59:59.000Z

    We have used transmission electron microscopy (TEM) to study the retention of vacancies in Al after rapid melting and resolidification of a thin (approx. 3 ..mu..m) surface layer using a pulsed (approx.50 ns) electron beam. After pulsing and aging at room temperature, TEM examination showed dislocation loops, which are interpreted to be due to the coalescence of the quenched-in vacancies on )111) planes as is the case for the loops observed in earlier furnace quenching studies. Our results indicate that the rapid melting and resolidification leaves a high vacancy concentration (approx.100 ppm) in the resolidified Al. Heat transport calculations show that cooling rates for the pulse heated samples (approx.10/sup 8/ K/s) are much higher than those achieved by conventional quenching techniques (approx. 10/sup 4/ K/s).

  11. Simulation of multicomponent evaporation in electron beam melting and refining

    SciTech Connect (OSTI)

    Powell, A.; Szekely, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Van Den Avyle, J.; Damkroger, B. [Sandia National Labs., Albuquerque, NM (United States)

    1996-06-01T23:59:59.000Z

    Experimental results and a mathematical model are presented to describe differential evaporation rates in electron beam melting of titanium alloys containing aluminum and vanadium. Experiments characterized the evaporation rate of commercially pure titanium, and vapor composition over titanium with up to 6% Al and 4.5% V content as a function of beam power, scan frequency and background pressure. The model is made up of a steady-state heat and mass transport model of a melting hearth and a model of transient thermal and flow behavior near the surface. Activity coefficients for aluminum and vanadium in titanium are roughly estimated by fitting model parameters to experimental results. Based on the ability to vary evaporation rate by 10-15% using scan frequency alone, we discuss the possibility of on-line composition control by means of intelligent manipulation of the electron beam.

  12. Hydrodynamic coarsening in phase-separated silicate melts

    E-Print Network [OSTI]

    David Bouttes; Océane Lambert; Corinne Claireaux; William Woelffel; Davy Dalmas; Emmanuelle Gouillart; Pierre Lhuissier; Luc Salvo; Elodie Boller; Damien Vandembroucq

    2015-02-12T23:59:59.000Z

    Using in-situ synchrotron tomography, we investigate the coarsening dynamics of barium borosilicate melts during phase separation. The 3-D geometry of the two interconnected phases is determined thanks to image processing. We observe a linear growth of the size of domains with time, at odds with the sublinear diffusive growth usually observed in phase-separating glasses or alloys. Such linear coarsening is attributed to viscous flow inside the bicontinuous phases, and quantitative measurements show that the growth rate is well explained by the ratio of surface tension over viscosity. The geometry of the domains is shown to be statistically similar at different times, provided that the microstructure is rescaled by the average domain size. Complementary experiments on melts with a droplet morphology demonstrate that viscous flow prevails over diffusion in the large range of domain sizes measured in our experiments (1 - 80 microns).

  13. Impact of graphite gasket/duplex stainless steel couples on crevice chemistry and likelihood of crevice attack in seawater

    SciTech Connect (OSTI)

    Turnbull, A. [National Physical Lab., Teddington (United Kingdom). Centre for Materials Measurement and Technology

    1998-12-31T23:59:59.000Z

    Electrochemical polarization measurements have been made on a graphite laminate gasket and a super-duplex stainless steel (DSS) in deaerated IM NaCl solution over a range of pH. The open circuit potential of the graphite is significantly more noble than that of the duplex stainless steel and the kinetics of the hydrogen ion reduction are greater at potentials more positive than about 0.0 V SCE. The data were used as input to a model of crevice chemistry and predictions made for potentials up to +0.4 V SCE. For crevices of parallel plates of DSS-DSS and DSS-Plastic, the usual acidic conditions were predicted but for a DSS-Graphite combination the pH was predicted to be alkaline. The latter is a consequence of the enhanced kinetics for cathodic reduction of hydrogen ions and water on the graphite which, when contained within the crevice, act to elevate the pH. The predictions suggest that coupling to graphite, contained within the crevice, may act to prevent crevice corrosion initiation in contrast to the usual perception of behavior when coupling to more noble materials. In practice, there have been significant crevice corrosion failures of a super-duplex stainless steel associated with graphite gaskets. However, in all cases, the failures were in chlorinated systems for which the corrosion potentials are particularly high and beyond the range for which a benefit from graphite could be anticipated.

  14. Removing a sheet from the surface of a melt using gas jets

    DOE Patents [OSTI]

    Kellerman, Peter L; Thronson, Gregory D; Sun, Dawei

    2014-04-01T23:59:59.000Z

    In one embodiment, a sheet production apparatus comprises a vessel configured to hold a melt of a material. A cooling plate is disposed proximate the melt and is configured to form a sheet of the material on the melt. A first gas jet is configured to direct a gas toward an edge of the vessel. A sheet of a material is translated horizontally on a surface of the melt and the sheet is removed from the melt. The first gas jet may be directed at the meniscus and may stabilize this meniscus or increase local pressure within the meniscus.

  15. Advanced coal-fired glass melting development program

    SciTech Connect (OSTI)

    Not Available

    1991-05-01T23:59:59.000Z

    The objective of Phase 1 of the current contract was to verify the technical feasibility and economic benefits of Vortec's advanced combustion/melting technology using coal as the fuel of choice. The objective of the Phase 2 effort was to improve the performance of the primary components and demonstrate the effective operation of a subscale process heater system integrated with a glass separator/reservoir. (VC)

  16. Proceedings of ALGORITMY 2005 BOUNDARY CONTROL OF SEMICONDUCTOR MELTS

    E-Print Network [OSTI]

    Hinze, Michael

    -type functionals of the form J(u, c) = 1 2 T 0 |u - u|2 ddt + 2 T 0 c (2 c + 2 ct ) ddt,(1) whereas goal (ii) may be related to minimal values of vorticity-type functionals of the form J(u, c) = 1 2 T 0 |curlu|2 ddt + 2 T 0 c (2 c + 2 ct ) ddt .(2) Above, u denotes the flow velocity vector field in the melt, and u

  17. Release of Residues from Melting NORM-Contaminated Steel Scrap - A German Approach

    SciTech Connect (OSTI)

    Quade, U.; Thierfeldt, S.; Wvrlen, S.

    2003-02-24T23:59:59.000Z

    As many raw materials like crude oil, natural gas, mineral sands, phosphor ores and others are contaminated by radionuclides from the Uranium and/or Thorium decay chain (NORM), also plants for processing these materials became contaminated during operation. When plants are shut down, large quantities of pipes, valves, pumps and other components have to be scrapped. As scrap yards and steel mills are equipped by large detector systems to avoid an input of radioactivity into the steel cycle, decontamination is required before recycling. Siempelkamp is operating a melting plant for processing NORM and/or chemically/ toxically contaminated steel scrap. Beside the decontaminated steel as output, residues like slag and filter dust have to be managed within the range of licensed values. Based on the European Safety Standard the European member states have to implement radiation exposure from work activities with NORM in their Radiation Protection Ordinances (RPO). The German government revised the RPO in July 2001. Part 3 describes exposure limits for workers and for the public. Exposures from residues management have to meet 1 mSv/year. Brenk Systemplanung has performed calculations for assessing the radiation exposure from residues of the Siempelkamp melting plant. These calculations have been based on the input of metal from different origins and include all relevant exposure pathways in a number of scenarios. The calculations have been based on the dose criterion of 1 mSv/y as required by the German RPO. The methods and results will be presented.

  18. Novel Phases and Reentrant Melting of Two Dimensional Colloidal Crystals

    E-Print Network [OSTI]

    Leo Radzihovsky; Erwin Frey; David R. Nelson

    2000-08-11T23:59:59.000Z

    We investigate two-dimensional (2d) melting in the presence of a one-dimensional (1d) periodic potential as, for example, realized in recent experiments on 2d colloids subjected to two interfering laser beams. The topology of the phase diagram is found to depend primarily on two factors: the relative orientation of the 2d crystal and the periodic potential troughs, which select a set of Bragg planes running parallel to the troughs, and the commensurability ratio p= a'/d of the spacing a' between these Bragg planes to the period d of the periodic potential. The complexity of the phase diagram increases with the magnitude of the commensurabilty ratio p. Rich phase diagram, with ``modulated liquid'', ``floating'' and ``locked floating'' solid and smectic phases are found. Phase transitions between these phases fall into two broad universality classes, roughening and melting, driven by the proliferation of discommensuration walls and dislocations, respectively. We discuss correlation functions and the static structure factor in these phases and make detailed predictions of the universal features close to the phase boundaries. We predict that for charged systems with highly screened short-range interactions these melting transitions are generically reentrant as a function of the strength of the periodic potential, prediction that is in accord with recent 2d colloid experiments. Implications of our results for future experiments are also discussed.

  19. A computational model for viscous fluid flow, heat transfer, and melting in in situ vitrification melt pools

    SciTech Connect (OSTI)

    McHugh, P.R.; Ramshaw, J.D.

    1991-11-01T23:59:59.000Z

    MAGMA is a FORTRAN computer code designed to viscous flow in in situ vitrification melt pools. It models three-dimensional, incompressible, viscous flow and heat transfer. The momentum equation is coupled to the temperature field through the buoyancy force terms arising from the Boussinesq approximation. All fluid properties, except density, are assumed variable. Density is assumed constant except in the buoyancy force terms in the momentum equation. A simple melting model based on the enthalpy method allows the study of the melt front progression and latent heat effects. An indirect addressing scheme used in the numerical solution of the momentum equation voids unnecessary calculations in cells devoid of liquid. Two-dimensional calculations can be performed using either rectangular or cylindrical coordinates, while three-dimensional calculations use rectangular coordinates. All derivatives are approximated by finite differences. The incompressible Navier-Stokes equations are solved using a new fully implicit iterative technique, while the energy equation is differenced explicitly in time. Spatial derivatives are written in conservative form using a uniform, rectangular, staggered mesh based on the marker and cell placement of variables. Convective terms are differenced using a weighted average of centered and donor cell differencing to ensure numerical stability. Complete descriptions of MAGMA governing equations, numerics, code structure, and code verification are provided. 14 refs.

  20. Author's personal copy Coexisting silicate melt inclusions and H2O-bearing, CO2-rich fluid inclusions in mantle

    E-Print Network [OSTI]

    Bodnar, Robert J.

    Author's personal copy Coexisting silicate melt inclusions and H2O-bearing, CO2-rich fluid­Pannonian region Hungary C­O­H­S fluid inclusions Peridotite xenoliths Silicate melt inclusions Volatile (fluid)­silicate melt immiscibility Coexisting fluid inclusions and silicate melt inclusions, trapped as primary

  1. On the Disposition of Graphite Containing TRISO Particles and the Aqueous Transport of Radionuclides via Heterogeneous Geological Formations

    E-Print Network [OSTI]

    van den Akker, Bret Patrick

    2012-01-01T23:59:59.000Z

    element) 0.225 (compact only) 5.144 Graphite CSNF 21-PWR12-PWR 44-BWR 24-BWR UO2 21 PWR fuel assemblies 12 PWR fuel assemblies, 44

  2. Use of coal tar pitch and petroleum bitumen in the production of thermally expanded graphite (Short Communication)

    SciTech Connect (OSTI)

    T.P. Miloshenko; O.Yu. Fetisova; M.L. Shchipko; B.N. Kuznetsov [Russian Academy of Sciences, Krasnoyarsk (Russia). Institute of Chemistry and Chemical Technology

    2008-06-15T23:59:59.000Z

    The applicability of coal tar pitch and petroleum bitumen to the production of thermally expanded graphite was studied. The dependence of the coefficient of thermal expansion and the specific surface area on the amount of added substances was examined.

  3. Abundances of presolar graphite and SiC from supernovae and AGB stars in the Murchison meteorite

    SciTech Connect (OSTI)

    Amari, Sachiko; Zinner, Ernst [McDonnell Center for the Space Sciences and the Physics Department, Washington University, One Brookings Dr., St. Louis, MO 63130 (United States); Gallino, Roberto [Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, I-10125 Torino (Italy)

    2014-05-02T23:59:59.000Z

    Pesolar graphite grains exhibit a range of densities (1.65 – 2.20 g/cm{sup 3}). We investigated abundances of presolar graphite grains formed in supernovae and in asymptotic giant branch (AGB) stars in the four density fractions KE3, KFA1, KFB1 and KFC1 extracted from the Murchison meteorite to probe dust productions in these stellar sources. Seventy-six and 50% of the grains in the low-density fractions KE3 and KFA1, respectively, are supernova grains, while only 7.2% and 0.9% of the grains in the high-density fractions KFB1 and KFC1 have a supernova origin. Grains of AGB star origin are concentrated in the high-density fractions KFB1 and KFC1. From the C isotopic distributions of these fractions and the presence of s-process Kr with {sup 86}Kr/{sup 82}Kr?=?4.43±0.46 in KFC1, we estimate that 76% and 80% of the grains in KFB1 and KFC1, respectively, formed in AGB stars. From the abundance of graphite grains in the Murchison meteorite, 0.88 ppm, the abundances of graphite from supernovae and AGB stars are 0.24 ppm and 0.44 ppm, respectively: the abundances of graphite in supernovae and AGB stars are comparable. In contrast, it has been known that 1% of SiC grains formed in supernovae and 95% formed in AGB stars in meteorites. Since the abundance of SiC grains is 5.85 ppm in the Murchison meteorite, the abundances of SiC from supernovae and AGB stars are 0.063 ppm and 5.6 ppm, respectively: the dominant source of SiC grains is AGB stars. Since SiC grains are harder and likely to survive better in space than graphite grains, the abundance of supernova graphite grains, which is higher than that of supernova SiC grains, indicates that supernovae proficiently produce graphite grains. Graphite grains from AGB stars are, in contrast, less abundant that SiC grains from AGB stars (0.44 ppm vs. 5.6 ppm). It is difficult to derive firm conclusions for graphite and SiC formation in AGB stars due to the difference in susceptibility to grain destruction. Metallicity of the parent AGB stars of graphite grains is much lower than that of SiC grains and the difference in metallicity might also have affected to the difference in the abundances in the Murchison meteorite.

  4. Effect of glass composition on activation energy of viscosity in glass-melting-temperature range

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Han, Sang Soo

    2012-08-01T23:59:59.000Z

    In the high-temperature range, where the viscosity (Eta) of molten glass is <10{sup 3} Pa s, the activation energy (B) is virtually ln(Eta) = A + B/T, is nearly independent of melt composition. Hence, the viscosity-composition relationship for Eta < 10{sup 3} Pa s is defined by B as a function of composition. Using a database encompassing over 1300 compositions of high-level waste glasses with nearly 7000 viscosity data, we developed mathematical models for B(x), where x is the composition vector in terms of mass fractions of components. In this paper, we present 13 versions of B(x) as first- and second-order polynomials with coefficients for 15 to 39 components, including Others, a component that sums constituents having little effect on viscosity.

  5. Experimental investigation of moisture and temperature conditioning of C600/5208 graphite/epoxy composite material 

    E-Print Network [OSTI]

    Grieger, Kenneth Allen

    1979-01-01T23:59:59.000Z

    I XPERIMENTAI INVESTIGATION OF MOI TURE AND TE11PERATURF CONDITIONING OF CGOO/5208 GRAPHITE/EPOXY COMPOSITE MATL'RIAL KENNETH AILEN GRIFGFR Su5&ritted to the Graduate College of Texa. s AQh University in partial fulfillment of the requirement... for the degree of MASTER OF SCIFNCE December 1979 Majo, Subject: Ae&ospace Engineering EXPERINENTAL INVESTIGATION OF MOISTURE AND TENPERATURE CONDITIONING OF C600/5208 GRAPHITE/EPOXY COMPOSITE HATERIAL A Thesis by -KENNETH ALLEN GRIEGER Approved...

  6. The determination of some anions using ion chromatography and ion chromatography-graphite furnace atomic absorption spectrometry 

    E-Print Network [OSTI]

    Hillman, Daniel C

    1981-01-01T23:59:59.000Z

    THE DETERMINATION OF SOME ANIONS USING ION CHROMATOGRAPHY AND ION CHROMATOGRAPHY-GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY A Thesis by DANIEL C. J. HILLMAN Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE August 1981 Major Subject: Chemistry THE DETERMINATION OF SOME ANIONS USING ION CHROMATOGRAPHY AND ION CHROMATOGRAPHY-GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY A Thesis by DANIEL C. J. HILLMAN...

  7. Moisture and temperature effects on curvature of anti-symmetric cross-ply graphite/epoxy laminates 

    E-Print Network [OSTI]

    Lott, Randall Stephen

    1980-01-01T23:59:59.000Z

    MOISTURE AND TEMPERATURE EFFECTS ON CURVATURE OF ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by RANDALL STEPHEN LOTT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1980 Major Subject: Mechanical Engineering MOISTURE AND TEMPERATURE EFFECTS ON CURVATURE OF ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by RANDALL STEPHEN LOTT Approved as to style and content...

  8. Hierarchical mesoporous/microporous carbon with graphitized frameworks for high-performance lithium-ion batteries

    SciTech Connect (OSTI)

    Lv, Yingying; Fang, Yin; Qian, Xufang; Tu, Bo [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China); Wu, Zhangxiong [Department of Chemical Engineering, Monash University, Clayton, VIC 3800 (Australia); Asiri, Abdullah M. [Chemistry Department and The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Zhao, Dongyuan, E-mail: dyzhao@fudan.edu.cn [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China); Department of Chemical Engineering, Monash University, Clayton, VIC 3800 (Australia)

    2014-11-01T23:59:59.000Z

    A hierarchical meso-/micro-porous graphitized carbon with uniform mesopores and ordered micropores, graphitized frameworks, and extra-high surface area of ?2200 m{sup 2}/g, was successfully synthesized through a simple one-step chemical vapor deposition process. The commercial mesoporous zeolite Y was utilized as a meso-/ micro-porous template, and the small-molecule methane was employed as a carbon precursor. The as-prepared hierarchical meso-/micro-porous carbons have homogeneously distributed mesopores as a host for electrolyte, which facilitate Li{sup +} ions transport to the large-area micropores, resulting a high reversible lithium ion storage of 1000 mA h/g and a high columbic efficiency of 65% at the first cycle.

  9. Examination of the solidification macrostructure of spheroidal and flake graphite cast irons using DAAS and ESBD

    SciTech Connect (OSTI)

    Rivera, G. [Metallurgy Division INTEMA, National University of Mar del Plata, CONICET, J. B. Justo 4302 (B7608FDQ) Mar del Plata (Argentina); Calvillo, P.R. [Department of Metallurgy and Materials Science, Ghent University (Belgium); Boeri, R. [Metallurgy Division INTEMA, National University of Mar del Plata, CONICET, J. B. Justo 4302 (B7608FDQ) Mar del Plata (Argentina)], E-mail: boeri@fi.mdp.edu.ar; Houbaert, Y. [Department of Metallurgy and Materials Science, Ghent University (Belgium); Sikora, J. [Metallurgy Division INTEMA, National University of Mar del Plata, CONICET, J. B. Justo 4302 (B7608FDQ) Mar del Plata (Argentina)], E-mail: jsikora@fi.mdp.edu.ar

    2008-09-15T23:59:59.000Z

    This investigation focuses on the study of the solidification macrostructure of sand cast flake and spheroidal graphite cast irons. The macrostructure is revealed by using a special technique developed earlier by the authors, called Direct Austempering After Solidification. The observations make use of conventional metallography and Electron Back Scattering Diffraction. The latter technique allows a more detailed observation of the morphology of the austenite grains and the microstructure of the matrix. The results of Electron Back Scattering Diffraction validate the observations made using the macrographic technique. It is verified that the solidification of both flake and spheroidal graphite cast irons is dominated by the growth of large austenite dendrites that form a grain pattern similar to that usually found in most metallic alloys.

  10. Composition monitoring of electron beam melting processes using diode lasers

    SciTech Connect (OSTI)

    Berzins, L.V.

    1991-11-20T23:59:59.000Z

    Electron beam melting processes are used to produce high purity alloys for a wide range of applications. Real time monitoring of the alloy constituents, however, has historically been difficult. Absorption spectroscopy using diode lasers provides a means for measuring constituent densities, and hence alloy composition, in real time. Diode lasers are suggested because they are inexpensive and require little maintenance. There is increasing interest in the composition and quality control of titanium alloys used in aircraft parts. For this reason we describe a proposed system for composition monitoring of titanium alloys. Performance and cost of the proposed system is addressed. We discuss the applicability of this approach to other alloys.

  11. Melt coolability modeling and comparison to MACE test results

    SciTech Connect (OSTI)

    Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.

    1992-04-01T23:59:59.000Z

    An important question in the assessment of severe accidents in light water nuclear reactors is the ability of water to quench a molten corium-concrete interaction and thereby terminate the accident progression. As part of the Melt Attack and Coolability Experiment (MACE) Program, phenomenological models of the corium quenching process are under development. The modeling approach considers both bulk cooldown and crust-limited heat transfer regimes, as well as criteria for the pool thermal hydraulic conditions which separate the two regimes. The model is then compared with results of the MACE experiments.

  12. Melt coolability modeling and comparison to MACE test results

    SciTech Connect (OSTI)

    Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.

    1992-01-01T23:59:59.000Z

    An important question in the assessment of severe accidents in light water nuclear reactors is the ability of water to quench a molten corium-concrete interaction and thereby terminate the accident progression. As part of the Melt Attack and Coolability Experiment (MACE) Program, phenomenological models of the corium quenching process are under development. The modeling approach considers both bulk cooldown and crust-limited heat transfer regimes, as well as criteria for the pool thermal hydraulic conditions which separate the two regimes. The model is then compared with results of the MACE experiments.

  13. Creep measuring device for low melting point metals

    E-Print Network [OSTI]

    Portal, Marc-Emmanuel Gilbert

    1987-01-01T23:59:59.000Z

    that there is little concern about the mechanical interaction of the coolant in the solid state and the walls. Because of its suitable thermophysicsl properties, lithium has been selected for the coolant in the SP-100 space reactor design. During launch, the lithium... properties of lithium. An experiment was conducted on lead at 90% of melting temperature (541 K). The results of this experiment agreed well with theoretical predictions of the Harper-Dorn creep model. The three predicted stages of creep were observed...

  14. Low-melting point inorganic nitrate salt heat transfer fluid

    DOE Patents [OSTI]

    Bradshaw, Robert W. (Livermore, CA); Brosseau, Douglas A. (Albuquerque, NM)

    2009-09-15T23:59:59.000Z

    A low-melting point, heat transfer fluid made of a mixture of four inorganic nitrate salts: 9-18 wt % NaNO.sub.3, 40-52 wt % KNO.sub.3, 13-21 wt % LiNO.sub.3, and 20-27 wt % Ca(NO.sub.3).sub.2. These compositions can have liquidus temperatures less than 100 C; thermal stability limits greater than 500 C; and viscosity in the range of 5-6 cP at 300 C; and 2-3 cP at 400 C.

  15. Sedimentation profiles of systems with reentrant melting behavior

    E-Print Network [OSTI]

    J. Dzubiella; H. M. Harreis; C. N. Likos; H. Lowen

    2001-01-26T23:59:59.000Z

    We examine sedimentation density profiles of star polymer solutions as an example of colloidal systems in sedimentation equilibrium which exhibit reentrant melting in their bulk phase diagram. Phase transitions between a fluid and a fluid with an intercalated solid are observed below a critical gravitational strength $\\alpha^{*}$. Characteristics of the two fluid-solid interfaces in the density profiles occurring in Monte Carlo simulations for $\\alpha laws put forth in the framework of a phenomenological theory. Furthermore we detect density oscillations at the fluid-gas interface at high altitudes for high gravitational fields, which are verified with density functional theory and should be observable in surface scattering experiments.

  16. ARM - Lesson Plans: When Floating Ice Melts in the Sea

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow, AlaskaWhen Floating Ice Melts in the Sea

  17. Measurements of the diffusion coefficient of silver 110-m in a nuclear grade graphite

    E-Print Network [OSTI]

    McMillan, Thad Calhoun

    1980-01-01T23:59:59.000Z

    in HTGRs. . . II. B Cesium Research. II. C Silver Research. 5 6 8 II. C. 1 Recognition of Importance of 110 m Ag II. C. 2 Current Work on 110 m Ag Diffusion in Structural Graphites. . . . . . . . . . . II. D Diffusion Theory. 10 10 II. D. 1... contaminating various reactor components can make their main- tainance costly and difficult. Additionally from the radiological safety viewpoint, in the event of a severe reactor transient it is essential to understand how fast fission products will leave...

  18. Method to Assess the Radionuclide Inventory of Irradiated Graphite from Gas-Cooled Reactors - 13072

    SciTech Connect (OSTI)

    Poncet, Bernard [EDF-CIDEN, 154 Avenue Thiers, CS 60018, F-69458 LYON cedex 06 (France)] [EDF-CIDEN, 154 Avenue Thiers, CS 60018, F-69458 LYON cedex 06 (France)

    2013-07-01T23:59:59.000Z

    About 17,000 t of irradiated graphite waste will be produced from the decommissioning of the six French gas-cooled nuclear reactors. Determining the radionuclide (RN) content of this waste is of relevant importance for safety reasons and in order to determine the best way to manage them. For many reasons the impurity content that gave rise to the RNs in irradiated graphite by neutron activation during operation is not always well known and sometimes actually unknown. So, assessing the RN content by the use of traditional calculation activation, starting from assumed impurity content, leads to a false assessment. Moreover, radiochemical measurements exhibit very wide discrepancies especially on RN corresponding to precursor at the trace level such as natural chlorine corresponding to chlorine 36. This wide discrepancy is unavoidable and is due to very simple reasons. The level of impurity is very low because the uranium fuel used at that very moment was not enriched, so it was a necessity to have very pure nuclear grade graphite and the very low size of radiochemical sample is a simple technical constraint because device size used to get mineralization product for measurement purpose is limited. The assessment of a radionuclide inventory only based on few number of radiochemical measurements lead in most cases, to a gross over or under-estimation that is detrimental for graphite waste management. A method using an identification calculation-measurement process is proposed in order to assess a radiological inventory for disposal sizing purpose as precise as possible while guaranteeing its upper character. This method present a closer approach to the reality of the main phenomenon at the origin of RNs in a reactor, while also incorporating the secondary effects that can alter this result such as RN (or its precursor) release during reactor operation. (authors)

  19. Recapturing Graphite-Based Fuel Element Technology for Nuclear Thermal Propulsion

    SciTech Connect (OSTI)

    Trammell, Michael P [ORNL; Jolly, Brian C [ORNL; Miller, James Henry [ORNL; Qualls, A L [ORNL; Harrison, Thomas J [ORNL

    2013-01-01T23:59:59.000Z

    ORNL is currently recapturing graphite based fuel forms for Nuclear Thermal Propulsion (NTP). This effort involves research and development on materials selection, extrusion, and coating processes to produce fuel elements representative of historical ROVER and NERVA fuel. Initially, lab scale specimens were fabricated using surrogate oxides to develop processing parameters that could be applied to full length NTP fuel elements. Progress toward understanding the effect of these processing parameters on surrogate fuel microstructure is presented.

  20. A solution to level 3 dismantling of gas-cooled reactors: Graphite incineration

    SciTech Connect (OSTI)

    Dubourg, M. [FRAMATOME, Paris-La Defense (France)

    1993-12-31T23:59:59.000Z

    This paper presents an approach developed to solve the specific decommissioning problems of the G2 and G3 gas cooled reactors at Marcoule and the strategy applied with emphasis in incinerating the graphite core components, using a fluidized-bed incinerator developed jointly between the CEA and FRAMATOME. The incineration option was selected over subsurface storage for technical and economic reasons. Studies have shown that gaseous incineration releases are environmentally acceptable.

  1. Direct exfoliation of natural graphite into micrometer size few layers graphene sheets using ionic liquids

    SciTech Connect (OSTI)

    Wang, X.; Fulvio, P. F.; Baker, G. A.; Veith, G. M.; Unocic, R. R.; Mahurin, S., M.; Chi, M.; Dai, S.

    2010-01-01T23:59:59.000Z

    Stable high-concentration suspensions (up to 0.95 mg mL{sup ?1}) of non-oxidized few layer graphene (FLG), five or less sheets, with micrometre-long edges were obtained via direct exfoliation of natural graphite flakes in ionic liquids, such as 1-butyl-3-methyl-imidazolium bis(trifluoro-methane-sulfonyl)imide ([Bmim]-[Tf{sub 2}N]), by tip ultrasonication.

  2. Chemical Distribution and Bonding of Lithium in Intercalated Graphite: Identification with Optimized Electron Energy Loss Spectroscopy

    SciTech Connect (OSTI)

    Wang, Feng; Graetz, Jason; Moreno, M. Sergio; Ma, Chao; Wu, Lijun; Volkov, Vyacheslav; Zhu, Yimei

    2011-01-01T23:59:59.000Z

    Direct mapping of the lithium spatial distribution and the chemical state provides critical information on structure-correlated lithium transport in electrode materials for lithium batteries. Nevertheless, probing lithium, the lightest solid element in the periodic table, poses an extreme challenge with traditional X-ray or electron scattering techniques due to its weak scattering power and vulnerability to radiation damage. Here, we report nanoscale maps of the lithium spatial distribution in electrochemically lithiated graphite using electron energy loss spectroscopy in the transmission electron microscope under optimized experimental conditions. The electronic structure of the discharged graphite was obtained from the near-edge fine structure of the Li and C K-edges and ab initio calculations. A 2.7 eV chemical shift of the Li K-edge, along with changes in the density of states, reveals the ionic nature of the intercalated lithium with significant charge transfer to the graphene sheets. Direct mapping of lithium in graphite revealed nanoscale inhomogeneities (nonstoichiometric regions), which are correlated with local phase separation and structural disorder (i.e., lattice distortion and dislocations) as observed by high-resolution transmission electron microscopy. The surface solid?electrolyte interphase (SEI) layer was also imaged and determined to have a thickness of 10?50 nm, covering both edge and basal planes with LiF as its primary inorganic component. The Li K-edge spectroscopy and mapping, combined with electron microscopy-based structural analysis provide a comprehensive view of the structure-correlated lithium intercalation in graphite and of the formation of the SEI layer.

  3. Chemical Distribution and Bonding of Lithium in Intercalated Graphite: Identification with Optimized Electron Energy Loss Spectroscopy

    SciTech Connect (OSTI)

    Zhu, Y.; Wang, F.; Graetz, J.; Moreno, M.S.; Ma, C.; Wu, L.; Volkov, V.

    2011-02-01T23:59:59.000Z

    Direct mapping of the lithium spatial distribution and the chemical state provides critical information on structure-correlated lithium transport in electrode materials for lithium batteries. Nevertheless, probing lithium, the lightest solid element in the periodic table, poses an extreme challenge with traditional X-ray or electron scattering techniques due to its weak scattering power and vulnerability to radiation damage. Here, we report nanoscale maps of the lithium spatial distribution in electrochemically lithiated graphite using electron energy loss spectroscopy in the transmission electron microscope under optimized experimental conditions. The electronic structure of the discharged graphite was obtained from the near-edge fine structure of the Li and C K-edges and ab initio calculations. A 2.7 eV chemical shift of the Li K-edge, along with changes in the density of states, reveals the ionic nature of the intercalated lithium with significant charge transfer to the graphene sheets. Direct mapping of lithium in graphite revealed nanoscale inhomogeneities (nonstoichiometric regions), which are correlated with local phase separation and structural disorder (i.e., lattice distortion and dislocations) as observed by high-resolution transmission electron microscopy. The surface solid-electrolyte interphase (SEI) layer was also imaged and determined to have a thickness of 10-50 nm, covering both edge and basal planes with LiF as its primary inorganic component. The Li K-edge spectroscopy and mapping, combined with electron microscopy-based structural analysis provide a comprehensive view of the structure-correlated lithium intercalation in graphite and of the formation of the SEI layer.

  4. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect (OSTI)

    Duffy, Stephen

    2013-09-09T23:59:59.000Z

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  5. C, N, AND O ISOTOPIC HETEROGENEITIES IN LOW-DENSITY SUPERNOVA GRAPHITE GRAINS FROM ORGUEIL

    SciTech Connect (OSTI)

    Groopman, Evan; Bernatowicz, Thomas; Zinner, Ernst, E-mail: eegroopm@physics.wustl.edu [Laboratory for Space Sciences, Washington University, One Brookings Drive, Campus Box 1105, Saint Louis, MO 63130 (United States)

    2012-07-20T23:59:59.000Z

    We report on the results of NanoSIMS isotope imaging of low-density supernova graphite grains from the Orgueil meteorite. 70 nm thick microtomed sections of three supernova graphite grains were deposited on Si wafers and isotopically imaged in the NanoSIMS. These sections contain hotspots of excesses in {sup 18}O and {sup 15}N, which are spatially well correlated, and are likely carried by internal TiC subgrains. These hotspots are considerably more enriched in {sup 18}O and {sup 15}N than the host graphite grain. Correlations between {sup 18}O and {sup 15}N excesses indicate that the grains incorporated material from the He/C supernova zone. Isotope images of the surfaces of some grains show heterogeneities in their N and O isotope compositions, with extreme excesses in {sup 15}N and {sup 18}O. In the microtome sections, we also observe two types of heterogeneities in the grains' C isotopic compositions: smooth, radial gradients in {sup 12}C/{sup 13}C, with this ratio trending toward solar with increasing radius; and highly anomalous pockets up to 2 {mu}m in size with {sup 12}C/{sup 13}C >> solar that are located near the centers of the grain sections. Partial isotopic equilibration does not likely explain the C isotopic heterogeneities. These grains and their constituent parts probably formed in a stellar environment with changing isotopic composition.

  6. Controlling the number of graphene sheets exfoliated from graphite by designed normal loading and frictional motion

    SciTech Connect (OSTI)

    Lee, Seungjun; Lu, Wei, E-mail: weilu@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-07-14T23:59:59.000Z

    We use molecular dynamics to study the exfoliation of patterned nanometer-sized graphite under various normal loading conditions for friction-induced exfoliation. Using highly ordered pyrolytic graphite (HOPG) as well as both amorphous and crystalline SiO{sub 2} substrate as example systems, we show that the exfoliation process is attributed to the corrugation of the HOPG surface and the atomistic roughness of the substrate when they contact under normal loading. The critical normal strain, at which the exfoliation occurs, is higher on a crystalline substrate than on an amorphous substrate. This effect is related to the atomistic flatness and stiffness of the crystalline surface. We observe that an increase of the van der Waals interaction between the graphite and the substrate results in a decrease of the critical normal strain for exfoliation. We find that the magnitude of the normal strain can effectively control the number of exfoliated graphene layers. This mechanism suggests a promising approach of applying designed normal loading while sliding to pattern controlled number of graphene layers or other two-dimensional materials on a substrate surface.

  7. MHK technologies include current energy conversion

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

    research leverages decades of experience in engineering and design and analysis (D&A) of wind power technologies, and its vast research complex, including high-performance...

  8. Quantitative estimates of velocity sensitivity to surface melt variations at a large Greenland outlet glacier

    E-Print Network [OSTI]

    Anderson, M.L.; Nettles, M.; Larsen, T.B.; Hamilton, Gordon S.; Stearns, Leigh

    2011-09-01T23:59:59.000Z

    front. Calving events at the glacier front produce tsunami signals in the tide-gauge record, which we use to verify our visual and seismic detections of major calving events. The combined calving dataset for 2008 that we use to correct the velocity... evolution in sensitivity to melt input indicates a nonlinear velocity response to surface melt, and points to the need for a better understanding of the response to melting, particularly as atmospheric temperatures rise. We believe that our results...

  9. Removing a sheet from the surface of a melt using elasticity and buoyancy

    DOE Patents [OSTI]

    Kellerman, Peter L.; Sun, Dawei; Helenbrook, Brian; Harvey, David S.

    2014-07-01T23:59:59.000Z

    Embodiments related to sheet production are disclosed. A melt of a material is cooled to form a sheet of the material on the melt. The sheet is formed in a first region at a first sheet height. The sheet is translated to a second region such that it has a second sheet height higher than the first sheet height. The sheet is then separated from the melt. A seed wafer may be used to form the sheet.

  10. A model for the latent heat of melting in free standing metal nanoparticles

    SciTech Connect (OSTI)

    Shin, Jeong-Heon; Deinert, Mark R., E-mail: mdeinert@mail.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78715 (United States)

    2014-04-28T23:59:59.000Z

    Nanoparticles of many metals are known to exhibit scale dependent latent heats of melting. Analytical models for this phenomenon have so far failed to completely capture the observed phenomena. Here we present a thermodynamic analysis for the melting of metal nanoparticles in terms of their internal energy and a scale dependent surface tension proposed by Tolman. The resulting model predicts the scale dependence of the latent heat of melting and is confirmed using published data for tin and aluminum.

  11. Interfacial tension between aluminum and chloride-fluoride melts

    SciTech Connect (OSTI)

    Silny, A. [Slovak Academy of Sciences, Bratislava (Slovakia). Inst. of Inorganic Chemistry] [Slovak Academy of Sciences, Bratislava (Slovakia). Inst. of Inorganic Chemistry; Utigard, T.A. [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science] [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science

    1996-11-01T23:59:59.000Z

    Scrap and recycled aluminum have to be remelted and refined before being made into useful new products. This often involves melting the aluminum under a molten salt cover in order to prevent oxidation and to enhance the coalescence and recovery of the molten metal. A technique was developed for the measurement of the interfacial tension between liquid metals and molten salts at elevated temperatures. The technique is based on the measurement of the capillary depression occurring when a capillary, which is moved vertically down through the molten salt layer, passes through the salt/metal interface. The depression is measured by simultaneous video recording of the immersion height of the alumina capillary and the position of a liquid meniscus in a horizontal tube connected to the alumina capillary. The interfacial tension was measured for (a) aluminum and an equimolar melt of NaCl + KCl with several salt additions at 1,000 K, (b) aluminum and NaCl + NaF at 1,123 K, and (c) aluminum and NaCl + KF at 1,123 K. It was found that the interfacial tension decreases with increasing amount of NaF, increases with the increasing amount of MgCl{sub 2} additions, remains unchanged with AlF{sub 3} additions, and slightly decreases with the addition of MgF{sub 2} and Na{sub 3}AlF{sub 6}.

  12. Microwires fabricated by glass-coated melt spinning

    SciTech Connect (OSTI)

    Zhao, Y. Y.; Li, H.; Hao, H. Y.; Li, M.; Zhang, Y. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, No. 30, Xueyuan Road, Beijing 100083 (China)] [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, No. 30, Xueyuan Road, Beijing 100083 (China); Liaw, P. K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200 (United States)] [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200 (United States)

    2013-07-15T23:59:59.000Z

    The glass-coated melt spinning method offers a route for the manufacture of metal filaments with a few micrometers in diameter in a single operation directly from the melt. Cobalt-based amorphous wires, Cu-15.0 atomic percent (at. %) Sn shape-memory wires, and Ni{sub 2}MnGa (atomic percent) ferromagnetic wires were successfully produced by this method. The cobalt-based amorphous wire is flexible, and Cu-15.0 at. % Sn shape-memory wires have the tensile elongation of 14%. However, because of chemical reaction with glass and oxidation, it is hard to make Cu–Al–Ni shape-memory wires and Ni–Nb–Sn amorphous wires. Conditions for preparing these materials were summarized, and the differences of the solidification processes among glass-coated amorphous cobalt-based wires, Cu-15.0 at. % Sn shape-memory wires, and Ni{sub 2}MnGa wires were analyzed and discussed.

  13. Mobile Melt-Dilute Technology Development Project FY 2005 Test Report

    SciTech Connect (OSTI)

    David A. Sell; Donald Fisher

    2006-01-01T23:59:59.000Z

    The adaptation of Melt-Dilute technology to a mobile and deployable platform progressed with the installation of the prototype air-cooled induction furnace and power generator in an ISO cargo container. Process equipment tests were conducted in FY’05 on two fronts: the melt container and its associated hardware and the mobile furnace and generator. Container design was validated through tests at elevated temperature and pressure, under vacuum, and subjected to impact. The Mobile Melt-Dilute (MMD) furnace and power source tests were completed per the plan. The tests provided information necessary to successfully melt and dilute HEU research reactor fuel assemblies.

  14. Ex-Vessel Core Melt Modeling Comparison between MELTSPREAD-CORQUENCH and MELCOR 2.1

    SciTech Connect (OSTI)

    Robb, Kevin R [ORNL; Farmer, Mitchell [Argonne National Laboratory (ANL); Francis, Matthew W [ORNL

    2014-03-01T23:59:59.000Z

    System-level code analyses by both United States and international researchers predict major core melting, bottom head failure, and corium-concrete interaction for Fukushima Daiichi Unit 1 (1F1). Although system codes such as MELCOR and MAAP are capable of capturing a wide range of accident phenomena, they currently do not contain detailed models for evaluating some ex-vessel core melt behavior. However, specialized codes containing more detailed modeling are available for melt spreading such as MELTSPREAD as well as long-term molten corium-concrete interaction (MCCI) and debris coolability such as CORQUENCH. In a preceding study, Enhanced Ex-Vessel Analysis for Fukushima Daiichi Unit 1: Melt Spreading and Core-Concrete Interaction Analyses with MELTSPREAD and CORQUENCH, the MELTSPREAD-CORQUENCH codes predicted the 1F1 core melt readily cooled in contrast to predictions by MELCOR. The user community has taken notice and is in the process of updating their systems codes; specifically MAAP and MELCOR, to improve and reduce conservatism in their ex-vessel core melt models. This report investigates why the MELCOR v2.1 code, compared to the MELTSPREAD and CORQUENCH 3.03 codes, yield differing predictions of ex-vessel melt progression. To accomplish this, the differences in the treatment of the ex-vessel melt with respect to melt spreading and long-term coolability are examined. The differences in modeling approaches are summarized, and a comparison of example code predictions is provided.

  15. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Final Summary Report

    SciTech Connect (OSTI)

    White, Thornton C [SCRA Appiled R& D

    2014-03-31T23:59:59.000Z

    Energy-Saving Melting and Revert Reduction Technology (E-SMARRT) is a balanced portfolio of R&D tasks that address energy-saving opportunities in the metalcasting industry. E-SMARRT was created to: • Improve important capabilities of castings • Reduce carbon footprint of the foundry industry • Develop new job opportunities in manufacturing • Significantly reduce metalcasting process energy consumption and includes R&D in the areas of: • Improvements in Melting Efficiency • Innovative Casting Processes for Yield Improvement/Revert Reduction • Instrumentation and Control Improvement • Material properties for Casting or Tooling Design Improvement The energy savings and process improvements developed under E-SMARRT have been made possible through the unique collaborative structure of the E-SMARRT partnership. The E-SMARRT team consisted of DOE’s Office of Industrial Technology, the three leading metalcasting technical associations in the U.S: the American Foundry Society; the North American Die Casting Association; and the Steel Founders’ Society of America; and SCRA Applied R&D, doing business as the Advanced Technology Institute (ATI), a recognized leader in distributed technology management. This team provided collaborative leadership to a complex industry composed of approximately 2,000 companies, 80% of which employ less than 100 people, and only 4% of which employ more than 250 people. Without collaboration, these new processes and technologies that enable energy efficiencies and environment-friendly improvements would have been slow to develop and had trouble obtaining a broad application. The E-SMARRT R&D tasks featured low-threshold energy efficiency improvements that are attractive to the domestic industry because they do not require major capital investment. The results of this portfolio of projects are significantly reducing metalcasting process energy consumption while improving the important capabilities of metalcastings. Through June 2014, the E-SMARRT program predicts an average annual estimated savings of 59 Trillion BTUs per year over a 10 year period through Advanced Melting Efficiencies and Innovative Casting Processes. Along with these energy savings, an estimated average annual estimate of CO2 reduction per year over a ten year period is 3.56 Million Metric Tons of Carbon Equivalent (MM TCE).

  16. Energy Saving Melting and Revert Reduction Technology: Innovative Semi-Solid Metal (SSM) Processing

    SciTech Connect (OSTI)

    Diran Apelian

    2012-08-15T23:59:59.000Z

    Semi-solid metal (SSM) processing has emerged as an attractive method for near-net-shape manufacturing due to the distinct advantages it holds over conventional near-net-shape forming technologies. These advantages include lower cycle time, increased die life, reduced porosity, reduced solidification shrinkage, improved mechanical properties, etc. SSM processing techniques can not only produce the complex dimensional details (e.g. thin-walled sections) associated with conventional high-pressure die castings, but also can produce high integrity castings currently attainable only with squeeze and low-pressure permanent mold casting processes. There are two primary semi-solid processing routes, (a) thixocasting and (b) rheocasting. In the thixocasting route, one starts from a non-dendritic solid precursor material that is specially prepared by a primary aluminum manufacturer, using continuous casting methods. Upon reheating this material into the mushy (a.k.a. "two-phase") zone, a thixotropic slurry is formed, which becomes the feed for the casting operation. In the rheocasting route (a.k.a. "slurry-on-demand" or "SoD"), one starts from the liquid state, and the thixotropic slurry is formed directly from the melt via careful thermal management of the system; the slurry is subsequently fed into the die cavity. Of these two routes, rheocasting is favored in that there is no premium added to the billet cost, and the scrap recycling issues are alleviated. The CRP (Trade Marked) is a process where the molten metal flows through a reactor prior to casting. The role of the reactor is to ensure that copious nucleation takes place and that the nuclei are well distributed throughout the system prior to entering the casting cavity. The CRP (Trade Marked) has been successfully applied in hyper-eutectic Al-Si alloys (i.e., 390 alloy) where two liquids of equal or different compositions and temperatures are mixed in the reactor and creating a SSM slurry. The process has been mostly used for hypo-eutectic Al-Si alloys (i.e., 356, 357, etc.) where a single melt passes through the reactor. In addition, the CRP (Trade Marked) was designed to be flexible for thixocasting or rheocasting applications as well as batch or continuous casting. Variable heat extraction rates can be obtained by controlling either the superheat of the melt, the temperature of the channel system, or the temperature of the reactor. This program had four main objectives all of which were focused on a mechanistic understanding of the process in order to be able to scale it up, to develop it into a robust process,and for SSM processing to be commercially used.

  17. A meteorological experiment in the melting zone of the Greenland ice sheet

    SciTech Connect (OSTI)

    Oerlemans, J. (Utrecht Univ. (Netherlands)); Vugts, H.F. (Free Univ. of Amsterdam (Netherlands))

    1993-03-01T23:59:59.000Z

    Preliminary results are described from a glaciometeorological experiment carried out in the margin (melting zone) of the Greenland ice sheet in the summers of 1990 and 1991. This work was initiated within the framework of a Dutch research program on land ice and sea level change. Seven meteostations were operated along a transect running from the tundra well onto the ice sheet. At the ice edge, humidity, temperature, and wind profiles were obtained with a tethered balloon. On the ice sheet, 90 km from the edge, a boundary-layer research unit, including a sound detecting and ranging system (SODAR) and a radio acoustic sounding system (RASS), was established. Although focusing on the relation between surface energy balance, glacier mass balance, and ice flow, the experiment has also delivered a unique dataset on the dynamics of the atmospheric boundary layer around the warm tundra-cold ice sheet transition. Unexpected behavior was found for the surface albedo during the melt season. Lowest values are not found close to the ice edge, which is usual for glaciers, but higher on the ice sheet. Meltwater accumulation due to inefficient surface drainage was found to be the cause for this. The wind regime is dominated by katabatic flow from the ice sheet. The katabatic layer is typically 100-200 m thick. Close to the ice edge, the flow exhibits a very regular daily rhythm, with maximum wind speed in the afternoon. Farther on the ice sheet, the regime changes, and wind speed reaches maximum values in late night/early morning.

  18. EE Regional Technology Roadmap Includes comparison

    E-Print Network [OSTI]

    EE Regional Technology Roadmap Includes comparison against 6th Power Plan (Update cyclically Data Clearinghouse BPA/RTF NEEA/Regional Programs Group Update Regional EE Technology Roadmap Lighting

  19. DIDACTICAL HOLOGRAPHIC EXHIBIT INCLUDING (HOLOGRAPHIC TELEVISION)

    E-Print Network [OSTI]

    de Aguiar, Marcus A. M.

    DIDACTICAL HOLOGRAPHIC EXHIBIT INCLUDING HoloTV (HOLOGRAPHIC TELEVISION) José J. Lunazzi , DanielCampinasSPBrasil Abstract: Our Institute of Physics exposes since 1980 didactical exhibitions of holography in Brazil where

  20. Sessions include: Beginning Farmer and Rancher

    E-Print Network [OSTI]

    Watson, Craig A.

    Sessions include: ­ Beginning Farmer and Rancher ­ New Markets and Regulations ­ Food Safety ­ Good Bug, Bad Bug ID ­ Horticulture ­ Hydroponics ­ Livestock and Pastured Poultry ­ Mushrooms ­ Organic ­ Live animal exhibits ­ Saturday evening social, and ­ Local foods Florida Small Farms and Alternative