National Library of Energy BETA

Sample records for artificial graphite suitable

  1. Efficient graphite ring heater suitable for diamond-anvil cells to 1300 K

    SciTech Connect (OSTI)

    Du Zhixue; Amulele, George; Lee, Kanani K. M.; Miyagi, Lowell

    2013-02-15

    In order to generate homogeneous high temperatures at high pressures, a ring-shaped graphite heater has been developed to resistively heat diamond-anvil cell (DAC) samples up to 1300 K. By putting the heater in direct contact with the diamond anvils, this graphite heater design features the following advantages: (1) efficient heating: sample can be heated to 1300 K while the DAC body temperature remains less than 800 K, eliminating the requirement of a special alloy for the DAC; (2) compact design: the sample can be analyzed with in situ measurements, e.g., x-ray, optical, and electrical probes are possible. In particular, the side access of the heater allows for radial x-ray diffraction (XRD) measurements in addition to traditional axial XRD.

  2. Brazing graphite to graphite

    DOE Patents [OSTI]

    Peterson, George R.

    1976-01-01

    Graphite is joined to graphite by employing both fine molybdenum powder as the brazing material and an annealing step that together produce a virtually metal-free joint exhibiting properties similar to those found in the parent graphite. Molybdenum powder is placed between the faying surfaces of two graphite parts and melted to form molybdenum carbide. The joint area is thereafter subjected to an annealing operation which diffuses the carbide away from the joint and into the graphite parts. Graphite dissolved by the dispersed molybdenum carbide precipitates into the joint area, replacing the molybdenum carbide to provide a joint of virtually graphite.

  3. GRAPHITE EXTRUSIONS

    DOE Patents [OSTI]

    Benziger, T.M.

    1959-01-20

    A new lubricant for graphite extrusion is described. In the past, graphite extrusion mixtures have bcen composed of coke or carbon black, together with a carbonaceous binder such as coal tar pitch, and a lubricant such as petrolatum or a colloidal suspension of graphite in glycerin or oil. Sinee sueh a lubricant is not soluble in, or compatible with the biiider liquid, such mixtures were difficult to extrude, and thc formed pieees lacked strength. This patent teaches tbe use of fatty acids as graphite extrusion lubricants and definite improvemcnts are realized thereby since the fatty acids are soluble in the binder liquid.

  4. Wave propagation in an epoxy-graphite laminate

    SciTech Connect (OSTI)

    Clements, B.E.; Johnson, J.N.; Addessio, F.L.

    1997-11-01

    The third-order, nonhomogenized, dynamic method of cells is used to calculate the particle velocity for a shock wave experiment involving an epoxy{endash}graphite laminate. Constitutive relations suitable for the various materials are used. This includes linear and nonlinear elasticity and, when appropriate, viscoelasticity. It is found to be beneficial to incorporate artificial viscosity into the analysis. Artificial viscosity successfully removes the unphysical high-frequency ringing in the numerical solutions of the theory, while leaving the physical oscillations, characteristic of wave propagation in a periodic laminate, largely undiminished. It also allows the viscoelastic relaxed moduli to be closer to their unrelaxed counterparts than in a previous calculation, thus making them more acceptable. The results agree well with the corresponding plate-impact experiment, and are compared to the second-order theory of Clements, Johnson, and Hixson [Phys. Rev. E, {bold 54}, 6876 (1996)]. {copyright} {ital 1997 American Institute of Physics.}

  5. Preparation of graphitic articles

    DOE Patents [OSTI]

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

    2010-05-11

    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.

  6. Chapter 20: Graphite

    SciTech Connect (OSTI)

    Burchell, Timothy D

    2012-01-01

    Graphite is truly a unique material. Its structure, from the nano- to the millimeter scale give it remarkable properties that lead to numerous and diverse applications. Graphite bond anisotropy, with strong in-plane covalent bonds and weak van der Waals type bonding between the planes, gives graphite its unique combination of properties. Easy shear of the crystal, facilitated by weak interplaner bonds allows graphite to be used as a dry lubricant, and is responsible for the substances name! The word graphite is derived from the Greek to write because of graphites ability to mark writing surfaces. Moreover, synthetic graphite contains within its structure, porosity spanning many orders of magnitude in size. The thermal closure of these pores profoundly affects the properties for example, graphite strength increases with temperature to temperatures in excess of 2200 C. Consequently, graphite is utilized in many high temperature applications. The basic physical properties of graphite are reviewed here. Graphite applications include metallurgical; (aluminum and steel production), single crystal silicon production, and metal casting; electrical (motor brushes and commutators); mechanical (seals, bearings and bushings); and nuclear applications, (see Chapter 91, Nuclear Graphite). Here we discuss the structure, manufacture, properties, and applications of Graphite.

  7. Electrode material comprising graphene-composite materials in a graphite

    Office of Scientific and Technical Information (OSTI)

    network (Patent) | DOEPatents Electrode material comprising graphene-composite materials in a graphite network Title: Electrode material comprising graphene-composite materials in a graphite network 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,

  8. Graphite Technology Development Plan

    SciTech Connect (OSTI)

    W. Windes; T. Burchell; M.Carroll

    2010-10-01

    The Next Generation Nuclear Plant (NGNP) will be a helium-cooled High Temperature Gas Reactor (HTGR) with a large graphite core. Graphite physically contains the fuel and comprises the majority of the core volume. Graphite has been used effectively as a structural and moderator material in both research and commercial high-temperature gas-cooled reactors. This development has resulted in graphite being established as a viable structural material for HTGRs. While the general characteristics necessary for producing nuclear grade graphite are understood, historical nuclear grades no longer exist. New grades must be fabricated, characterized, and irradiated to demonstrate that current grades of graphite exhibit acceptable non-irradiated and irradiated properties upon which the thermomechanical design of the structural graphite in NGNP is based. This Technology Development Plan outlines the research and development (R&D) activities and associated rationale necessary to qualify nuclear grade graphite for use within the NGNP reactor.

  9. Graphite matrix materials for nuclear waste isolation

    SciTech Connect (OSTI)

    Morgan, W.C.

    1981-06-01

    At low temperatures, graphites are chemically inert to all but the strongest oxidizing agents. The raw materials from which artificial graphites are produced are plentiful and inexpensive. Morover, the physical properties of artificial graphites can be varied over a very wide range by the choice of raw materials and manufacturing processes. Manufacturing processes are reviewed herein, with primary emphasis on those processes which might be used to produce a graphite matrix for the waste forms. The approach, recommended herein, involves the low-temperature compaction of a finely ground powder produced from graphitized petroleum coke. The resultant compacts should have fairly good strength, low permeability to both liquids and gases, and anisotropic physical properties. In particular, the anisotropy of the thermal expansion coefficients and the thermal conductivity should be advantageous for this application. With two possible exceptions, the graphite matrix appears to be superior to the metal alloy matrices which have been recommended in prior studies. The two possible exceptions are the requirements on strength and permeability; both requirements will be strongly influenced by the containment design, including the choice of materials and the waste form, of the multibarrier package. Various methods for increasing the strength, and for decreasing the permeability of the matrix, are reviewed and discussed in the sections in Incorporation of Other Materials and Elimination of Porosity. However, it would be premature to recommend a particular process until the overall multi-barrier design is better defined. It is recommended that increased emphasis be placed on further development of the low-temperature compacted graphite matrix concept.

  10. Oxidation Resistant Graphite Studies

    SciTech Connect (OSTI)

    W. Windes; R. Smith

    2014-07-01

    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.

  11. Coating method for graphite

    DOE Patents [OSTI]

    Banker, John G.; Holcombe, Jr., Cressie E.

    1977-01-01

    A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided comprising coating the graphite surface with a suspension of Y.sub.2 O.sub.3 particles in water containing about 1.5 to 4% by weight sodium carboxymethylcellulose.

  12. Coating method for graphite

    DOE Patents [OSTI]

    Banker, J.G.; Holcombe, C.E. Jr.

    1975-11-06

    A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided. The graphite surface is coated with a suspension of Y/sub 2/O/sub 3/ particles in water containing about 1.5 to 4 percent by weight sodium carboxymethylcellulose.

  13. Method for producing dustless graphite spheres from waste graphite fines

    DOE Patents [OSTI]

    Pappano, Peter J (Oak Ridge, TN); Rogers, Michael R (Clinton, TN)

    2012-05-08

    A method for producing graphite spheres from graphite fines by charging a quantity of spherical media into a rotatable cylindrical overcoater, charging a quantity of graphite fines into the overcoater thereby forming a first mixture of spherical media and graphite fines, rotating the overcoater at a speed such that the first mixture climbs the wall of the overcoater before rolling back down to the bottom thereby forming a second mixture of spherical media, graphite fines, and graphite spheres, removing the second mixture from the overcoater, sieving the second mixture to separate graphite spheres, charging the first mixture back into the overcoater, charging an additional quantity of graphite fines into the overcoater, adjusting processing parameters like overcoater dimensions, graphite fines charge, overcoater rotation speed, overcoater angle of rotation, and overcoater time of rotation, before repeating the steps until graphite fines are converted to graphite spheres.

  14. NEW METHOD OF GRAPHITE PREPARATION

    DOE Patents [OSTI]

    Stoddard, S.D.; Harper, W.T.

    1961-08-29

    BS>A method is described for producing graphite objects comprising mixing coal tar pitch, carbon black, and a material selected from the class comprising raw coke, calcined coke, and graphite flour. The mixture is placed in a graphite mold, pressurized to at least 1200 psi, and baked and graphitized by heating to about 2500 deg C while maintaining such pressure. (AEC)

  15. Graphite Gamma Scan Results

    SciTech Connect (OSTI)

    Mark W. Drigert

    2014-04-01

    This report documents the measurement and data analysis of the radio isotopic content for a series of graphite specimens irradiated in the first Advanced Graphite Creep (AGC) experiment, AGC-1. This is the first of a series of six capsules planned as part of the AGC experiment to fully characterize the neutron irradiation effects and radiation creep behavior of current nuclear graphites. The AGC-1 capsule was irradiated in the Advanced Test Reactor (ATR) at INL at approximately 700 degrees C and to a peak dose of 7 dpa (displacements per atom). Details of the irradiation conditions and other characterization measurements performed on specimens in the AGC-1 capsule can be found in “AGC-1 Specimen Post Irradiation Data Report” ORNL/TM 2013/242. Two specimens from six different graphite types are analyzed here. Each specimen is 12.7 mm in diameter by 25.4 mm long. The isotope with the highest activity was 60Co. Graphite type NBG-18 had the highest content of 60Co with an activity of 142.89 µCi at a measurement distance of 47 cm.

  16. Recompressed exfoliated graphite articles

    DOE Patents [OSTI]

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

    2013-08-06

    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.

  17. Irradiation Creep in Graphite

    SciTech Connect (OSTI)

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    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.

  18. Diamond-graphite field emitters

    DOE Patents [OSTI]

    Valone, Steven M.

    1997-01-01

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

  19. Graphite-based photovoltaic cells

    DOE Patents [OSTI]

    Lagally, Max; Liu, Feng

    2010-12-28

    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.

  20. GRAPHITE BONDING METHOD

    DOE Patents [OSTI]

    King, L.D.P.

    1964-02-25

    A process for bonding or joining graphite members together in which a thin platinum foil is placed between the members, heated in an inert atmosphere to a temperature of 1800 deg C, and then cooled to room temperature is described. (AEC)

  1. Artificial photosynthesis

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

    Artificial photosynthesis Authors: Gust, D., Moore, T.A., and Moore, A.L. Title: Artificial photosynthesis Source: Theoretical and Experimental Plant Physiology Year: 2013 Volume: 25 Pages: 182-185 ABSTRACT: Photosynthesis is the largest-scale, longest-tested, and most important solar energy conversion system on earth. Photosynthetic organisms provide fuel for most of the biosphere, and generated the fossil fuels that account for about 85% of the energy used today by human technology. In a time

  2. Characterisation of graphite using boron as a marker element

    SciTech Connect (OSTI)

    Kamble, Granthali S.; Pandey, Shailaja; Thakur, Neha; Kumar, Sanjukta A.; Venkatesh, K.; Kumar, Sangita D.; Kameswaran, R.; Reddy, A. V. R.

    2013-06-12

    Graphite has many industrial applications. Two of the most important applications are as electrodes in industries and as moderator in nuclear industry. Determination of the Boron Equivalent of the impurity elements in graphite is the most important parameter for certifying the grade of graphite electrode [1]. The use of a suitable method with low limits of determination of boron is therefore necessary. A method has been standardised in Analytical Chemistry Division, BARC for determining trace amounts of boron in graphite electrodes. It involves controlled dissolution of graphite sample powder and measurement of boron by Inductively Coupled Plasma Mass Spectrometer (ICP-MS) using matrix matched standards. The method detection limit is 1 {mu}g g{sup -1}. The method Relative Standard Deviation was 5%. The method was verified by spike recovery experiments. Recoveries were found to be within 100{+-}2% in the concentration range of 1 to 100 {mu}g g{sup -1}. The developed method has been adopted for the compositional characterization of several graphite electrode samples.

  3. Heat exchanger using graphite foam

    DOE Patents [OSTI]

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    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.

  4. Graphitic packing removal tool

    DOE Patents [OSTI]

    Meyers, Kurt Edward; Kolsun, George J.

    1997-01-01

    Graphitic packing removal tools for removal of the seal rings in one piece. he packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

  5. Graphitic packing removal tool

    DOE Patents [OSTI]

    Meyers, K.E.; Kolsun, G.J.

    1997-11-11

    Graphitic packing removal tools for removal of the seal rings in one piece are disclosed. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal. 5 figs.

  6. REFRACTORY COATING FOR GRAPHITE MOLDS

    DOE Patents [OSTI]

    Stoddard, S.D.

    1958-06-24

    Refractory coating for graphite molds used in the casting of uranium is described. The coating is an alumino-silicate refractory composition which may be used as a mold surface in solid form or as a coating applied to the graphite mold. The composition consists of a mixture of ball clay, kaolin, alumina cement, alumina, water, sodium silicate, and sodium carbonate.

  7. Baseline Graphite Characterization: First Billet

    SciTech Connect (OSTI)

    Mark C. Carroll; Joe Lords; David Rohrbaugh

    2010-09-01

    The Next Generation Nuclear Plant Project Graphite Research and Development program is currently establishing the safe operating envelope of graphite core components for a very high temperature reactor design. To meet this goal, the program is generating the extensive amount of quantitative data necessary for predicting the behavior and operating performance of the available nuclear graphite grades. In order determine the in-service behavior of the graphite for the latest proposed designs, two main programs are underway. The first, the Advanced Graphite Creep (AGC) program, is a set of experiments that are designed to evaluate the irradiated properties and behavior of nuclear grade graphite over a large spectrum of temperatures, neutron fluences, and compressive loads. Despite the aggressive experimental matrix that comprises the set of AGC test runs, a limited amount of data can be generated based upon the availability of space within the Advanced Test Reactor and the geometric constraints placed on the AGC specimens that will be inserted. In order to supplement the AGC data set, the Baseline Graphite Characterization program will endeavor to provide supplemental data that will characterize the inherent property variability in nuclear-grade graphite without the testing constraints of the AGC program. This variability in properties is a natural artifact of graphite due to the geologic raw materials that are utilized in its production. This variability will be quantified not only within a single billet of as-produced graphite, but also from billets within a single lot, billets from different lots of the same grade, and across different billets of the numerous grades of nuclear graphite that are presently available. The thorough understanding of this variability will provide added detail to the irradiated property data, and provide a more thorough understanding of the behavior of graphite that will be used in reactor design and licensing. This report covers the development of the Baseline Graphite Characterization program from a testing and data collection standpoint through the completion of characterization on the first billet of nuclear-grade graphite. This data set is the starting point for all future evaluations and comparisons of material properties.

  8. Metal-bonded graphite foam composites

    DOE Patents [OSTI]

    Menchhofer, Paul A; Klett, James W

    2015-04-28

    A metal-bonded graphite foam composite includes a ductile metal continuous phase and a dispersed phase that includes graphite foam particles.

  9. Artificial Soiling

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

    Artificial Soiling of Photovoltaic Module Surfaces using Traceable Soil Components Patrick D. Burton and Bruce H. King Sandia National Laboratories Albuquerque NM 87185 USA Email: pdburto@sandia.gov Abstract-Effective evaluation and prediction of photovoltaic performance loss due to soiling requires consistent test methods. Natural grime accumulation is time-consuming and location- specific, and thus does not provide reproducible results across different geographic regions. Therefore, we have

  10. Method of Obtaining Uniform Coatings on Graphite

    DOE Patents [OSTI]

    Campbell, I. E.

    1961-04-01

    A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

  11. METHOD OF OBTAINING UNIFORM COATINGS ON GRAPHITE

    DOE Patents [OSTI]

    Campbell, I.E.

    1961-04-01

    A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

  12. CALANDRIA TYPE SODIUM GRAPHITE REACTOR

    DOE Patents [OSTI]

    Peterson, R.M.; Mahlmeister, J.E.; Vaughn, N.E.; Sanders, W.J.; Williams, A.C.

    1964-02-11

    A sodium graphite power reactor in which the unclad graphite moderator and fuel elements are contained within a core tank is described. The core tank is submersed in sodium within the reactor vessel. Extending longitudinally through the core thnk are process tubes with fuel elements positioned therein. A bellows sealing means allows axial expansion and construction of the tubes. Within the core tank, a leakage plenum is located below the graphite, and above the graphite is a gas space. A vent line regulates the gas pressure in the space, and another line removes sodium from the plenum. The sodium coolant flows from the lower reactor vessel through the annular space between the fuel elements and process tubes and out into the reactor vessel space above the core tank. From there, the heated coolant is drawn off through an outlet line and sent to the heat exchange. (AEC)

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

    DOE Patents [OSTI]

    Hoenig, Clarence L.

    1994-01-01

    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.

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

    DOE Patents [OSTI]

    Hoenig, C.L.

    1994-08-09

    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. GRAFEC: A New Spanish Program to Investigate Waste Management Options for Radioactive Graphite - 12399

    SciTech Connect (OSTI)

    Marquez, Eva; Pina, Gabriel; Rodriguez, Marina; Fachinger, Johannes; Grosse, Karl-Heinz; Leganes Nieto, Jose Luis; Quiros Gracian, Maria

    2012-07-01

    Spain has to manage about 3700 tons of irradiated graphite from the reactor Vandellos I as radioactive waste. 2700 tons are the stack of the reactor and are still in the reactor core waiting for retrieval. The rest of the quantities, 1000 tons, are the graphite sleeves which have been already retrieved from the reactor. During operation the graphite sleeves were stored in a silo and during the dismantling stage a retrieval process was carried out separating the wires from the graphite, which were crushed and introduced into 220 cubic containers of 6 m{sup 3} each and placed in interim storage. The graphite is an intermediate level radioactive waste but it contains long lived radionuclides like {sup 14}C which disqualifies disposal at the low level waste repository of El Cabril. Therefore, a new project has been started in order to investigate two new options for the management of this waste type. The first one is based on a selective decontamination of {sup 14}C by thermal methods. This method is based on results obtained at the Research Centre Juelich (FZJ) in the Frame of the EC programs 'Raphael' and 'Carbowaste'. The process developed at FZJ is based on a preferential oxidation of {sup 14}C in comparison to the bulk {sup 12}C. Explanations for this effect are the inhomogeneous distribution and a weaker bounding of {sup 14}C which is not incorporated in the graphite lattice. However these investigations have only been performed with graphite from the high temperature reactor Arbeitsgemeinschaft Versuchsreaktor Juelich AVR which has been operated in a non-oxidising condition or research reactor graphite operated at room temperature. The reactor Vandellos I has been operated with CO{sub 2} as coolant and significant amounts of graphite have been already oxidised. The aim of the project is to validate whether a {sup 14}C decontamination can also been achieved with graphite from Vandellos I. A second possibility under investigation is the encapsulation of the graphite in a long term stable glass matrix. The principal applicability has been already proved by FNAG. Crushed graphite mixed with a suitable glass powder has been pressed at elevated temperature under vacuum. The vacuum is required to avoid gas enclosures in the obtained product. The obtained products, named IGM for 'Impermeable Graphite Matrix', have densities above 99% of theoretical density. The amount of glass has been chosen with respect to the pore volume of the former graphite parts. The method allows the production of encapsulated graphite without increasing the disposal volume. This paper will give a short overview of characterisation results of different irradiated graphite materials obtained at CIEMAT and in the Carbowaste project as well as the proposed methods and the actual status of the program including first results about leaching of non-radioactive IGM samples and hopefully first tendencies concerning the C-14 separation from graphite of Vandellos I by thermal treatment. Both processes, the thermal treatment as well as the IGM, have the potential to solve problems related to the management of irradiated graphite in Spain. However the methods have only been tested with different types of i-graphite and virgin graphite, respectively. Only investigations with real i-graphite from Spain will reveal whether the described methods are applicable to graphite from Vandellos I. However all partners are convinced that one of these new methods or a combination of them will lead to a feasible option to manage i-graphite in Spain on an industrial scale. (authors)

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

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

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

  17. Composition and method for brazing graphite to graphite

    DOE Patents [OSTI]

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

    1984-01-01

    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.

  18. 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

    2012-09-25

    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.

  19. RECOVERY OF VALUABLE MATERIAL FROM GRAPHITE BODIES

    DOE Patents [OSTI]

    Fromm, L.W. Jr.

    1959-09-01

    An electrolytic process for recovering uranium from a graphite fuel element is described. The uraniumcontaining graphite body is disposed as the anode of a cell containing a nitric acid electrolyte and a 5 amp/cm/sup 2/ current passed to induce a progressive disintegration of the graphite body. The dissolved uranium is quickly and easily separated from the resulting graphite particles by simple mechanical means, such as centrifugation, filtration, and decontamination.

  20. X-10 Graphite Reactor | Department of Energy

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

    X-10 Graphite Reactor X-10 Graphite Reactor X-10 Graphite Reactor When President Roosevelt in December 1942 authorized the Manhattan Project, the Oak Ridge site in eastern Tennessee had already been obtained and plans laid for an air-cooled experimental pile, a pilot chemical separation plant, and support facilities. The X-10 Graphite Reactor, designed and built in ten months, went into operation on November 4, 1943. The X-10 used neutrons emitted in the fission of uranium-235 to convert

  1. Slurry Molding Technologies for Novel Carbon and Graphite Materials

    SciTech Connect (OSTI)

    Burchell, T.D.

    2004-06-30

    The Oak Ridge National Laboratory (ORNL) has developed a slurry molding technology for the manufacture of porous, high surface area, carbon fiber composites molecular sieves, and carbon-carbon composite preforms. Potentially, this technology could be applied to the manufacture of a host of novel carbon materials including porous adsorbent carbons, low-pressure drop adsorbent carbon composites, ultra-fine-grained graphite, and carbon fiber reinforced graphite. New opportunities for high surface carbon fiber composite molecular sieve (CFCMS) materials are now emerging. Many of these opportunities are driven by increasingly harsh environmental pressures. Traditional granular activated carbon (GAC) is not suitable for many of these applications because of the difficulties encountered with attrition and in forming ''structures'' which have the necessary mechanical and physical properties. In addition, the electrical desorption of adsorbed species is not possible with GAC due to its low bulk electrical conductivity. Activated carbon fibers have been found to be useful in some applications. Work by ORNL has shown, for example, that CFCMS materials are capable of adsorbing various gases and desorbing them under electrical stimulation. For some applications these fibers have to be formed into a structure that can offer the desired mechanical integrity and pressure drop characteristics. To date, the work by ORNL has focused on the use of a single manufacturer's isotropic pitch fibers which, when activated, may be cost prohibitive for many applications. Fine-grained graphite is attractive for many applications including the chemical processing industry where their unique combination of properties--including high strength and chemical inertness, are particularly attractive. However, a lack of toughness can limit their utility in certain applications. The use of ultra-fine powders in conjunction with slurry molding and hot pressing offers the possibility of higher strength graphite. Moreover, the inclusion of carbon fibers may provide a toughening mechanism, resulting in tougher, stronger graphite at an attractive cost. The objective of this work was to further develop the ORNL slurry molding technology and apply it to the following tasks: (1) the development of low cost, high surface area CFCMS materials and structures; (2) the development of ultra-fine-grained graphite; and (3) to identify suitable applications for the materials developed in (1) and (2). The work was conducted jointly by SGL and ORNL.

  2. Composition and method for brazing graphite to graphite

    DOE Patents [OSTI]

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

    1982-08-10

    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.

  3. Electrode material comprising graphene-composite materials in a graphite network

    DOE Patents [OSTI]

    Kung, Harold H.; Lee, Jung K.

    2014-07-15

    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.

  4. Fission Product Sorptivity in Graphite

    SciTech Connect (OSTI)

    Tompson, Jr., Robert V.; Loyalka, Sudarshan; Ghosh, Tushar; Viswanath, Dabir; Walton, Kyle; Haffner, Robert

    2015-04-01

    Both adsorption and absorption (sorption) of fission product (FP) gases on/into graphite are issues of interest in very high temperature reactors (VHTRs). In the original proposal, we proposed to use packed beds of graphite particles to measure sorption at a variety of temperatures and to use an electrodynamic balance (EDB) to measure sorption onto single graphite particles (a few ?m in diameter) at room temperature. The use of packed beds at elevated temperature is not an issue. However, the TPOC requested revision of this initial proposal to included single particle measurements at elevated temperatures up to 1100 C. To accommodate the desire of NEUP to extend the single particle EDB measurements to elevated temperatures it was necessary to significantly revise the plan and the budget. These revisions were approved. In the EDB method, we levitate a single graphite particle (the size, surface characteristics, morphology, purity, and composition of the particle can be varied) or agglomerate in the balance and measure the sorption of species by observing the changes in mass. This process involves the use of an electron stepping technique to measure the total charge on a particle which, in conjunction with the measured suspension voltages for the particle, allows for determinations of mass and, hence, of mass changes which then correspond to measurements of sorption. Accommodating elevated temperatures with this type of system required a significant system redesign and required additional time that ultimately was not available. These constraints also meant that the grant had to focus on fewer species as a result. Overall, the extension of the original proposed single particle work to elevated temperatures added greatly to the complexity of the proposed project and added greatly to the time that would eventually be required as well. This means that the bulk of the experimental progress was made using the packed bed sorption systems. Only being able to recruit one graduate student meant that data acquisition with the packed bed systems ended up competing for the graduate students available time with the electrodynamic balance redesign and assembly portions of the project. This competition for available time was eventually mitigated to some extent by the later recruitment of an undergraduate student to help with data collection using the packed bed system. It was only the recruitment of the second student that allowed the single particle balance design and construction efforts to proceed as far as they did during the project period. It should be added that some significant time was also spent by the graduate student cataloging previous work involving graphite. This eventually resulted in a review paper being submitted and accepted (Adsorption of Iodine on Graphite in High Temperature Gas-Cooled Reactor Systems: A Review, Kyle L. Walton, Tushar K. Ghosh, Dabir S. Viswanath, Sudarshan K. Loyalka, Robert V. Tompson). Our specific revised objectives in this project were as follows: Experimentally obtain isotherms of Iodine for reactor grade IG-110 samples of graphite particles over a range of temperatures and pressures using an EDB and a temperature controlled EDB; Experimentally obtain isotherms of Iodine for reactor grade IG-110 samples of graphite particles over a range of temperatures and pressures using a packed column bed apparatus; Explore the effect that charge has on the adsorption isotherms of iodine by varying the charges on and the voltages used to suspend the microscopic particles in the EDB; and To interpret these results in terms of the existing models (Langmuir, BET, Freundlich, and others) which we will modify as necessary to include charge related effects.

  5. AGC-3 Graphite Preirradiation Data Analysis Report

    SciTech Connect (OSTI)

    William Windes; David Swank; David Rohrbaugh; Joseph Lord

    2013-09-01

    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.

  6. 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.

    2012-01-23

    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 reactors lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.

  7. Using Graphite to view network data

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

    Graphite to Visualize Network Data Jon Dugan <jdugan@es.net> Summer ESCC 2010, Columbus, OH Lawrence Berkeley National Laboratory U.S. Department of Energy | Office of Science ESnet Statistics Overview ESxSNMP (Data Collection) ESxSNMP (Data Collection) Graphite (Visualization) Graphite (Visualization) Analytics (Custom Reports) Analytics (Custom Reports) Net Almanac (Metadata) Net Almanac (Metadata) Lawrence Berkeley National Laboratory U.S. Department of Energy | Office of Science What

  8. Graphite and its Hidden Superconductivity | Stanford Synchrotron...

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

    located at certain surfaces or interfaces between semiconducting crystalline regions with Bernal stacking order inside graphite samples. Recently published theoretical works...

  9. Graphite and its Hidden Superconductivity | Stanford Synchrotron...

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

    located at certain surfaces or interfaces between semiconducting crystalline regions with Bernal stacking order inside graphite samples. Recently published theoretical works 9,10...

  10. Determining whether metals nucleate homogeneously on graphite...

    Office of Scientific and Technical Information (OSTI)

    on surface terraces of graphite as a result of physical vapor deposition in ultrahigh vacuum. We show that the observation is incompatible with a variety of models incorporating...

  11. Graphitized-carbon fiber/carbon char fuel

    DOE Patents [OSTI]

    Cooper, John F.

    2007-08-28

    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.

  12. SIMPLIFIED SODIUM GRAPHITE REACTOR SYSTEM

    DOE Patents [OSTI]

    Dickinson, R.W.

    1963-03-01

    This patent relates to a nuclear power reactor comprising a reactor vessel, shielding means positioned at the top of said vessel, means sealing said reactor vessel to said shielding means, said vessel containing a quantity of sodium, a core tank, unclad graphite moderator disposed in said tank, means including a plurality of process tubes traversing said tank for isolating said graphite from said sodium, fuel elements positioned in said process tubes, said core tank being supported in spaced relation to the walls and bottom of said reactor vessel and below the level of said sodium, neutron shielding means positioned adjacent said core tank between said core tank and the walls of said vessel, said neutron shielding means defining an annuiar volume adjacent the inside wall of said reactor vessel, inlet plenum means below said core tank for providing a passage between said annular volume and said process tubes, heat exchanger means removably supported from the first-named shielding means and positioned in said annular volume, and means for circulating said sodium over said neutron shielding means down through said heat exchanger, across said inlet plenum and upward through said process tubes, said last-named means including electromagnetic pumps located outside said vessel and supported on said vessel wall between said heat exchanger means and said inlet plenum means. (AEC)

  13. PLASMA PHYSICS AND FUSION TECHNOLOGY; GRAPHITE; CREEP; PHYSICAL...

    Office of Scientific and Technical Information (OSTI)

    creep of graphite) Kennedy, C.R. 36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; GRAPHITE; CREEP; PHYSICAL RADIATION EFFECTS; JAPAN; MEETINGS; TRAVEL; ASIA; CARBON;...

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

    Energy Savers [EERE]

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

  15. Characterization of structural defects in nuclear graphite IG...

    Office of Scientific and Technical Information (OSTI)

    Characterization of structural defects in nuclear graphite IG-110 and NBG-18 Citation Details In-Document Search Title: Characterization of structural defects in nuclear graphite ...

  16. First Direct Evidence of Dirac Fermions in Graphite

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

    of finite effective mass and defect-induced localized states. Goodbye Silicon Valley, Hello Graphite Gulch? Why are scientists suddenly interested in graphite? It is, after all,...

  17. Modeling Fission Product Sorption in Graphite Structures

    SciTech Connect (OSTI)

    Szlufarska, Izabela; Morgan, Dane; Allen, Todd

    2013-04-08

    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).

  18. AGC-2 Graphite Preirradiation Data Analysis Report

    SciTech Connect (OSTI)

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

    2013-08-01

    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. Superconductivity in graphite intercalation compounds

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

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

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ 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 statesmore » 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.« less

  20. Realizing artificial photosynthesis

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

    Artificial photosynthesis comprises the design of systems for converting solar energy into ... In this report, the emphasis is on molecule-based systems for photochemical production ...

  1. Method for molding threads in graphite panels

    DOE Patents [OSTI]

    Short, W.W.; Spencer, C.

    1994-11-29

    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.

  2. Method for molding threads in graphite panels

    DOE Patents [OSTI]

    Short, William W.; Spencer, Cecil

    1994-01-01

    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).

  3. X-10 Graphite Reactor | Department of Energy

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

    in eastern Tennessee had already been obtained and plans laid for an air-cooled experimental pile, a pilot chemical separation plant, and support facilities. The X-10 Graphite...

  4. Immobilization of Rocky Flats Graphite Fines Residue

    SciTech Connect (OSTI)

    Rudisill, T.S.

    1999-04-06

    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.

  5. Analysis of Picosecond Pulsed Laser Melted Graphite

    DOE R&D Accomplishments [OSTI]

    Steinbeck, J.; Braunstein, G.; Speck, J.; Dresselhaus, M. S.; Huang, C. Y.; Malvezzi, A. M.; Bloembergen, N.

    1986-12-01

    A Raman microprobe and high resolution TEM have been used to analyze the resolidified region of liquid carbon generated by picosecond pulse laser radiation. From the relative intensities of the zone center Raman-allowed mode for graphite at 1582 cm{sup -1} and the disorder-induced mode at 1360 cm{sup -1}, the average graphite crystallite size in the resolidified region is determined as a function of position. By comparison with Rutherford backscattering spectra and Raman spectra from nanosecond pulsed laser melting experiments, the disorder depth for picosecond pulsed laser melted graphite is determined as a function of irradiating energy density. Comparisons of TEM micrographs for nanosecond and picosecond pulsed laser melting experiments show that the structure of the laser disordered regions in graphite are similar and exhibit similar behavior with increasing laser pulse fluence.

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

    SciTech Connect (OSTI)

    Stevenson, Cynthia; Hardwick, Laurence J.; Marcinek, Marek; Beer, Leanne; Kerr, John B.; Kostecki, Robert

    2008-03-03

    The effect of surface structural damage on graphitic anodes, commonly observed in tested Li-ion cells, was investigated. Similar surface structural disorder was artificially induced in Mag-10 synthetic graphite anodes using argon-ion sputtering. Raman microscopy, scanning electron microscopy (SEM) and Brunauer Emmett Teller (BET) measurements confirmed that Ar-ion sputtered Mag-10 electrodes display similar degree of surface degradation as the anodes from tested Li-ion cells. Artificially modified Mag-10 anodes showed double the irreversible charge capacity during the first formation cycle, compared to fresh un-altered anodes. Impedance spectroscopy and Fourier transform infrared (FTIR) spectroscopy on surface modified graphite anodes indicated the formation of a thicker and slightly more resistive SEI layer. Gas chromatography/mass spectroscopy (GC/MS) analysis of solvent extracts from the electrodes detected the presence of new compounds with M{sub w} on the order of 1600 g mol{sup -1} for the surface modified electrode with no evidence of elevated M{sub w} species for the unmodified electrode. The structural disorder induced in the graphite during long-term cycling maybe responsible for the slow and continuous SEI layer reformation, and consequently, the loss of reversible capacity due to the shift of lithium inventory in cycled Li-ion cells.

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

    SciTech Connect (OSTI)

    Jung, Hanyung; Ve Cheah, Chang; Jeong, Namjo; Lee, Junghoon

    2014-08-04

    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.

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

    DOE Patents [OSTI]

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

    2010-11-02

    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.

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

    DOE Patents [OSTI]

    Bunnell, L. Roy (Kennewick, WA)

    1993-01-01

    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.

  10. Kelvin probe characterization of buried graphitic microchannels in single-crystal diamond

    SciTech Connect (OSTI)

    Bernardi, E. Battiato, A.; Olivero, P.; Vittone, E.; Picollo, F.

    2015-01-14

    In this work, we present an investigation by Kelvin Probe Microscopy (KPM) of buried graphitic microchannels fabricated in single-crystal diamond by direct MeV ion microbeam writing. Metal deposition of variable-thickness masks was adopted to implant channels with emerging endpoints and high temperature annealing was performed in order to induce the graphitization of the highly-damaged buried region. When an electrical current was flowing through the biased buried channel, the structure was clearly evidenced by KPM maps of the electrical potential of the surface region overlying the channel at increasing distances from the grounded electrode. The KPM profiling shows regions of opposite contrast located at different distances from the endpoints of the channel. This effect is attributed to the different electrical conduction properties of the surface and of the buried graphitic layer. The model adopted to interpret these KPM maps and profiles proved to be suitable for the electronic characterization of buried conductive channels, providing a non-invasive method to measure the local resistivity with a micrometer resolution. The results demonstrate the potential of the technique as a powerful diagnostic tool to monitor the functionality of all-carbon graphite/diamond devices to be fabricated by MeV ion beam lithography.

  11. Nondestructive evaluation of nuclear-grade graphite

    SciTech Connect (OSTI)

    Kunerth, D. C.; McJunkin, T. R.

    2012-05-17

    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.

  12. Immobilization of Rocky Flats graphite fines residues

    SciTech Connect (OSTI)

    Rudisill, T.S.; Marra, J.C.; Peeler, D.K.

    1999-07-01

    The Savannah River Technology Center (SRTC) is developing an immobilization process for graphite fines residues generated during nuclear materials production activities at the Rocky Flats Environmental Technology Site (Rocky Flats). The continued storage of this material has been identified as an item of concern. The residue was generated during the cleaning of graphite casting molds and potentially contains reactive plutonium metal. The average residue composition is 73 wt% graphite, 15 wt% calcium fluoride (CaF{sub 2}), and 12 wt% plutonium oxide (PuO{sub 2}). Approximately 950 kg of this material are currently stored at Rocky Flats. The strategy of the immobilization process is to microencapsulate the residue by mixing with a sodium borosilicate (NBS) glass frit and heating at nominally 700 C. The resulting waste form would be sent to the Waste Isolation Pilot Plant (WIPP) for disposal. Since the PuO{sub 2} concentration in the residue averages 12 wt%, the immobilization process was required to meet the intent of safeguards termination criteria by limiting plutonium recoverability based on a test developed by Rocky Flats. The test required a plutonium recovery of less than 4 g/kg of waste form when a sample was leached using a nitric acid/CaF{sub 2} dissolution flowsheet. Immobilization experiments were performed using simulated graphite fines with cerium oxide (CeO{sub 2}) as a surrogate for PuO{sub 2} and with actual graphite fines residues. Small-scale surrogate experiments demonstrated that a 4:1 frit to residue ratio was adequate to prevent recovery of greater than 4 g/kg of cerium from simulated waste forms. Additional experiments investigated the impact of varying concentrations of CaF{sub 2} and the temperature/heating time cycle on the cerium recovery. Optimal processing conditions developed during these experiments were subsequently demonstrated at full-scale with surrogate materials and on a smaller scale using actual graphite fines.

  13. Chemically modified graphite for electrochemical cells

    DOE Patents [OSTI]

    Greinke, Ronald Alfred (Medina, OH); Lewis, Irwin Charles (Strongsville, OH)

    1998-01-01

    This invention relates to chemically modified graphite particles: (a) that are useful in alkali metal-containing electrode of a electrochemical cell comprising: (i) the electrode, (ii) 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 (iii) a counterelectrode; 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.

  14. HIGH TEMPERATURE REFRACTORY COATING FOR GRAPHITE MOLDS

    DOE Patents [OSTI]

    Stoddard, S.D.

    1958-10-21

    An improved foundry mold coating for use with graphite molds used in the casting of uranium is presented. The refractory mold coating serves to keep the molten uranium from contact with graphite of the mold and thus prevents carbon pickup by the molten metal. The refractory coating is made by dry mixing certain specific amounts of aluminum oxide, bentonite, Tennessee ball clay, and a soluble silicate salt. Water is then added to the mixture and the suspension thus formed is applied by spraying onto the mold.

  15. Chemically modified graphite for electrochemical cells

    DOE Patents [OSTI]

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

    1998-05-26

    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.

  16. 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...

  17. High order reflectivity of graphite (HOPG) crystals for x ray...

    Office of Scientific and Technical Information (OSTI)

    High order reflectivity of graphite (HOPG) crystals for x ray energies up to 22 keV Citation Details In-Document Search Title: High order reflectivity of graphite (HOPG) crystals ...

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

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

    web site | Department of Energy 10th International Nuclear Graphite Specialists Meeting registration web site PIA - 10th International Nuclear Graphite Specialists Meeting registration web site PIA - 10th International Nuclear Graphite Specialists Meeting registration web site PDF icon PIA - 10th International Nuclear Graphite Specialists Meeting registration web site More Documents & Publications Integrated Safety Management Workshop Registration, PIA, Idaho National Laboratory

  19. Method of making segmented pyrolytic graphite sputtering targets

    DOE Patents [OSTI]

    McKernan, Mark A. (Livermore, CA); Alford, Craig S. (Tracy, CA); Makowiecki, Daniel M. (Livermore, CA); Chen, Chih-Wen (Livermore, CA)

    1994-01-01

    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.

  20. METHOD OF COATING GRAPHITE WITH STABLE METAL CARBIDES AND NITRIDES

    DOE Patents [OSTI]

    Gurinsky, D.H.

    1959-10-27

    A method is presented for forming protective stable nitride and carbide compounds on the surface of graphite. This is accomplished by contacting the graphite surface with a fused heavy liquid metal such as bismuth or leadbismuth containing zirconium, titanium, and hafnium dissolved or finely dispersed therein to form a carbide and nitride of at least one of the dissolved metals on the graphite surface.

  1. Method of making segmented pyrolytic graphite sputtering targets

    DOE Patents [OSTI]

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

    1994-02-08

    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.

  2. US graphite reactor D&D experience

    SciTech Connect (OSTI)

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

    1997-02-01

    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).

  3. Graphite Oxidation Simulation in HTR Accident Conditions

    SciTech Connect (OSTI)

    El-Genk, Mohamed

    2012-10-19

    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.

  4. Analysis of Natural Graphite, Synthetic Graphite, and Thermosetting Resin Candidates for Use in Fuel Compact Matrix

    SciTech Connect (OSTI)

    Trammell, Michael P; Pappano, Peter J

    2011-09-01

    The AGR-1 and AGR-2 compacting process involved overcoating TRISO particles and compacting them in a steel die. The overcoating step is the process of applying matrix to the OPyC layer of TRISO particles in a rotating drum in order to build up an overcoat layer of desired thickness. The matrix used in overcoating is a mixture of natural graphite, synthetic graphite, and thermosetting resin in the ratio, by weight, of 64:16:20. A wet mixing process was used for AGR-1 and AGR-2, in that the graphites and resin were mixed in the presence of ethyl alcohol. The goal of the wet mixing process was to 'resinate' the graphite particles, or coat each individual graphite particle with a thin layer of resin. This matrix production process was similar to the German, Chinese, Japanese, and South African methods, which also use various amount of solvent during mixing. See Appendix 1 for information on these countries matrix production techniques. The resin used for AGR-1 and AGR-2 was provided by Hexion, specifically Hexion grade Durite SC1008. Durite SC1008 is a solvated (liquid) resole phenolic resin. A resole resin does not typically have a hardening agent added. The major constituent of SC1008 is phenol, with minor amounts of formaldehyde. Durite SC1008 is high viscosity, so additional ethyl alcohol was added during matrix production in order to reduce its viscosity and enhance graphite particle resination. The current compacting scale up plan departs from a wet mixing process. The matrix production method specified in the scale up plan is a co-grinding jet mill process where powdered phenolic resin and graphite are all fed into a jet mill at the same time. Because of the change in matrix production style, SC1008 cannot be used in the jet milling process because it is a liquid. The jet milling/mixing process requires that a suite of solid or powdered resins be investigated. The synthetic graphite used in AGR-1 and AGR-2 was provided by SGL Carbon, grade KRB2000. KRB2000 is a graphitized petroleum coke. The availability of KRB2000 is perhaps in question, so a replacement synthetic graphite may need to be identified. This report presents data on potential replacements for KRB2000.

  5. Temperature Dependence of Phonons in Pyrolitic Graphite

    DOE R&D Accomplishments [OSTI]

    Brockhouse, B. N.; Shirane, G.

    1977-01-01

    Dispersion curves for longitudinal and transverse phonons propagating along and near the c-axis in pyrolitic graphite at temperatures between 4°K and 1500°C have been measured by neutron spectroscopy. The observed frequencies decrease markedly with increasing temperature (except for the transverse optical ''rippling'' modes in the hexagonal planes). The neutron groups show interesting asymmetrical broadening ascribed to interference between one phonon and many phonon processes.

  6. Atomic resolution images of graphite in air

    SciTech Connect (OSTI)

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

    1988-12-01

    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.

  7. Differentiating the role of lithium and oxygen in retaining deuterium on lithiated graphite plasma-facing components

    SciTech Connect (OSTI)

    C.N. Taylor; J. P. Allain; P. S. Krstic; J. Dadras; C. H. Skinner; K. E. Luitjohan

    2013-11-01

    Laboratory experiments have been used to investigate the fundamental interactions responsible for deuterium retention in lithiated graphite. Oxygen was found to be present and play a key role in experiments that simulated NSTX lithium conditioning, where the atomic surface concentration can increase to >40% when deuterium retention chemistry is observed. Quantum-classical molecular dynamic simulations elucidated this oxygen-deuterium effect and showed that oxygen retains significantly more deuterium than lithium in a simulated matrix with 20% lithium, 20% oxygen, and 60% carbon. Simulations further show that deuterium retention is even higher when lithium is removed from the matrix. Experiments artificially increased the oxygen content in graphite to approximately 16% and then bombarded with deuterium. XPS showed depletion of the oxygen and no enhanced deuterium retention, thus demonstrating that lithium is essential in retaining the oxygen that thereby retains deuterium.

  8. Differentiating the role of lithium and oxygen in retaining deuterium on lithiated graphite plasma-facing components

    SciTech Connect (OSTI)

    Taylor, C. N. [Fusion Safety Program, Idaho National Laboratory, P.O. Box 1625-7113, Idaho Falls, Idaho 83415 (United States) [Fusion Safety Program, Idaho National Laboratory, P.O. Box 1625-7113, Idaho Falls, Idaho 83415 (United States); School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, Indiana 47907 (United States); Allain, J. P. [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, Indiana 47907 (United States) [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, Indiana 47907 (United States); Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Illinois 61801 (United States); Luitjohan, K. E. [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, Indiana 47907 (United States)] [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, Indiana 47907 (United States); Krstic, P. S. [Institute for Advanced Computational Science, Stony Brook University, New York 11794 (United States) [Institute for Advanced Computational Science, Stony Brook University, New York 11794 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); TheoretiK, Knoxville, Tennessee 379XX (United States); Dadras, J. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States) [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095 (United States); Skinner, C. H. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-05-15

    Laboratory experiments have been used to investigate the fundamental interactions responsible for deuterium retention in lithiated graphite. Oxygen was found to be present and play a key role in experiments that simulated NSTX lithium conditioning, where the atomic surface concentration can increase to >40% when deuterium retention chemistry is observed. Quantum-classical molecular dynamic simulations elucidated this oxygen-deuterium effect and showed that oxygen retains significantly more deuterium than lithium in a simulated matrix with 20% lithium, 20% oxygen, and 60% carbon. Simulations further show that deuterium retention is even higher when lithium is removed from the matrix. Experiments artificially increased the oxygen content in graphite to ?16% and then bombarded with deuterium. X-ray photoelectron spectroscopy showed depletion of the oxygen and no enhanced deuterium retention, thus demonstrating that lithium is essential in retaining the oxygen that thereby retains deuterium.

  9. Immobilization of Rocky Flats Graphite Fines Residues

    SciTech Connect (OSTI)

    Rudisill, T. S.

    1998-11-06

    The Savannah River Technology Center (SRTC) is developing an immobilization process for graphite fines residues generated during nuclear materials production activities at the Rocky Flats Environmental Technology Site (Rocky Flats). The continued storage of this material has been identified as an item of concern. The residue was generated during the cleaning of graphite casting molds and potentially contains reactive plutonium metal. The average residue composition is 73 wt percent graphite, 15 wt percent calcium fluoride (CaF2), and 12 wt percent plutonium oxide (PuO2). Approximately 950 kilograms of this material are currently stored at Rocky Flats. The strategy of the immobilization process is to microencapsulate the residue by mixing with a sodium borosilicate (NBS) glass frit and heating at nominally 700 degrees C. The resulting waste form would be sent to the Waste Isolation Pilot Plant (WIPP) for disposal. Since the PuO2 concentration in the residue averages 12 wt percent, the immobilization process was required to meet the intent of safeguards termination criteria by limiting plutonium recoverability based on a test developed by Rocky Flats. The test required a plutonium recovery of less than 4 g/kg of waste form when a sample was leached using a nitric acid/CaF2 dissolution flowsheet. Immobilization experiments were performed using simulated graphite fines with cerium oxide (CeO2) as a surrogate for PuO2 and with actual graphite fines residues. Small-scale surrogate experiments demonstrated that a 4:1 frit to residue ratio was adequate to prevent recovery of greater than 4 g/kg of cerium from simulated waste forms. Additional experiments investigated the impact of varying concentrations of CaF2 and the temperature/heating time cycle on the cerium recovery. Optimal processing conditions developed during these experiments were subsequently demonstrated at full-scale with surrogate materials and on a smaller scale using actual graphite fines.In general, the recovery of cerium from the full-scale waste forms was higher than for smaller scale experiments. The presence of CaF2 also caused a dramatic increase in cerium recovery not seen in the small-scale experiments. However, the results from experiments with actual graphite fines were encouraging. A 4:1 frit to residue ratio, a temperature of 700 degrees C, and a 2 hr heating time produced waste forms with plutonium recoveries of 4 plus/minus 1 g/kg. With an increase in the frit to residue ratio, waste forms fabricated at this scale should meet the Rocky Flats product specification. The scale-up of the waste form fabrication process to nominally 3 kg is expected to require a 5:1 to 6:1 frit to residue ratio and maintaining the waste form centerline temperature at 700 degrees C for 2 hr.

  10. Comparison between the Strength Levels of Baseline Nuclear-Grade Graphite and Graphite Irradiated in AGC-2

    SciTech Connect (OSTI)

    Carroll, Mark Christopher

    2015-07-01

    This report details the initial comparison of mechanical strength properties between the cylindrical nuclear-grade graphite specimens irradiated in the second Advanced Graphite Creep (AGC-2) experiment with the established baseline, or unirradiated, mechanical properties compiled in the Baseline Graphite Characterization program. The overall comparative analysis will describe the development of an appropriate test protocol for irradiated specimens, the execution of the mechanical tests on the AGC-2 sample population, and will further discuss the data in terms of developing an accurate irradiated property distribution in the limited amount of irradiated data by leveraging the considerably larger property datasets being captured in the Baseline Graphite Characterization program. Integrating information on the inherent variability in nuclear-grade graphite with more complete datasets is one of the goals of the VHTR Graphite Materials program. Between “sister” specimens, or specimens with the same geometry machined from the same sub-block of graphite from which the irradiated AGC specimens were extracted, and the Baseline datasets, a comprehensive body of data will exist that can provide both a direct and indirect indication of the full irradiated property distributions that can be expected of irradiated nuclear-grade graphite while in service in a VHTR system. While the most critical data will remain the actual irradiated property measurements, expansion of this data into accurate distributions based on the inherent variability in graphite properties will be a crucial step in qualifying graphite for nuclear use as a structural material in a VHTR environment.

  11. Suitability of Varicose Veins for Endovenous Treatments

    SciTech Connect (OSTI)

    Goode, S. D.; Kuhan, G.; Altaf, N.; Simpson, R.; Beech, A.; Richards, T.; MacSweeney, S. T.; Braithwaite, B. D.

    2009-09-15

    The aim of the study was to assess the suitability of radiofrequency ablation (RFA), endovenous laser ablation (EVLA), and foam sclerotherapy (FS) for patients with symptomatic varicose veins (VVs). The study comprised 403 consecutive patients with symptomatic VVs. Data on 577 legs from 403 consecutive patients with symptomatic VVs were collected for the year 2006. Median patient age was 55 years (interquartile range 45-66), and 62% patients were women. A set of criteria based on duplex ultrasonography was used to select patients for each procedure. Great saphenous vein (GSV) reflux was present in 77% (446 of 577) of legs. Overall, 328 (73%) of the legs were suitable for at least one of the endovenous options. Of the 114 legs with recurrent GSV reflux disease, 83 (73%) were suitable to receive endovenous therapy. Patients with increasing age were less likely to be suitable for endovenous therapy (P = 0.03). Seventy-three percent of patients with VVs caused by GSV incompetence are suitable for endovenous therapy.

  12. Characterization of structural defects in nuclear graphite IG-110 and

    Office of Scientific and Technical Information (OSTI)

    NBG-18 (Journal Article) | SciTech Connect Characterization of structural defects in nuclear graphite IG-110 and NBG-18 Citation Details In-Document Search Title: Characterization of structural defects in nuclear graphite IG-110 and NBG-18 Nuclear graphite IG-110 and NBG-18 were examined using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM) and high resolution transmission electron microscope (HR-TEM) to understand the structure and microstructure of nuclear

  13. Brookhaven Graphite Research Reactor Workshop | Department of Energy

    Energy Savers [EERE]

    Services » Site & Facility Restoration » Deactivation & Decommissioning (D&D) » D&D Workshops » Brookhaven Graphite Research Reactor Workshop Brookhaven Graphite Research Reactor Workshop 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 operating in August 1950. In the next 18 years, an estimated 25,000 scientific experiments were

  14. Tritium Related Material Research -Irradiation Effect on Isotropic Graphite

    Office of Environmental Management (EM)

    Utilizing Heavy Ion-Irradiation- | Department of Energy Related Material Research -Irradiation Effect on Isotropic Graphite Utilizing Heavy Ion-Irradiation- Tritium Related Material Research -Irradiation Effect on Isotropic Graphite Utilizing Heavy Ion-Irradiation- Presentation from the 34th Tritium Focus Group Meeting held in Idaho Falls, Idaho on September 23-25, 2014. PDF icon Tritium Related Material Research -Irradiation Effect on Isotropic Graphite Utilizing Heavy Ion-Irradiation- More

  15. Transition metals on the (0001) surface of graphite: Fundamental...

    Office of Scientific and Technical Information (OSTI)

    metals on the (0001) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology Citation Details In-Document Search Title: Transition metals on the...

  16. 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

    2014-09-16

    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.

  17. PROCESS OF COATING GRAPHITE WITH NIOBIUM-TITANIUM CARBIDE

    DOE Patents [OSTI]

    Halden, F.A.; Smiley, W.D.; Hruz, F.M.

    1961-07-01

    A process of coating graphite with niobium - titanium carbide is described. It is found that the addition of more than ten percent by weight of titanium to niobium results in much greater wetting of the graphite by the niobium and a much more adherent coating. The preferred embodiment comprises contacting the graphite with a powdered alloy or mixture, degassing simultaneously the powder and the graphite, and then heating them to a high temperature to cause melting, wetting, spreading, and carburization of the niobium-titanium powder.

  18. Toughened Graphite Electrode for High Heat Electric Arc Furnaces...

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

    Technology Marketing SummaryA tougher and more resilient graphite electrode was developed at ORNL to melt steel, titanium, and other scrap metal in industrial electric arc ...

  19. Novel Electrolyte Enables Stable Graphite Anodes in Lithium Ion...

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

    Novel Electrolyte Enables Stable Graphite Anodes in Lithium Ion Batteries Lawrence ... Coulombic Efficiency for Lithium Ion Batteries," Journal of the Electrochemical ...

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

    SciTech Connect (OSTI)

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

    2014-11-01

    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.

  1. Nanoscale, multidimensional artificial magnet created

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

    Nanoscale, multidimensional artificial magnet created Nanoscale, multidimensional artificial magnet created Applications might range from general magnetism, such as developing sensors, to information encoding. October 26, 2015 Researchers have created a nanoscale, artificial magnet by arranging an array of magnetic nano-islands along a geometry that is not found in natural magnets. As temperature is reduced, magnetic nanoislands (in blue) reach a one-dimensional static, ordered state, while

  2. JACKETED FUEL ELEMENTS FOR GRAPHITE MODERATED REACTORS

    DOE Patents [OSTI]

    Szilard, L.; Wigner, E.P.; Creutz, E.C.

    1959-05-12

    Fuel elements for a heterogeneous, fluid cooled, graphite moderated reactor are described. The fuel elements are comprised of a body of natural uranium hermetically sealed in a jacket of corrosion resistant material. The jacket, which may be aluminum or some other material which is non-fissionable and of a type having a low neutron capture cross-section, acts as a barrier between the fissioning isotope and the coolant or moderator or both. The jacket minimizes the tendency of the moderator and coolant to become radioactive and/or contaminated by fission fragments from the fissioning isotope.

  3. The shear fracture toughness, KIIc, of graphite

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

    Burchell, Timothy D.; Erdman, III, Donald L.

    2015-11-05

    In this study, the critical shear stress intensity factor, KIIc, here-in referred to as the shear fracture toughness, KIIc (MPa m), of two grades of graphite are reported. The range of specimen volumes was selected to elucidate any specimen size effect, but smaller volume specimen tests were largely unsuccessful, shear failure did not occur between the notches as expected. This was probably due to the specimen geometry causing the shear fracture stress to exceed the compressive failure stress. In subsequent testing the specimen geometry was altered to reduce the compressive footprint and the notches (slits) made deeper to reduce themore » specimen's ligament length. Additionally, we added the collection of Acoustic Emission (AE) during testing to assist with the identification of the shear fracture load. The means of KIIc from large specimens for PCEA and NBG-18 are 2.26 MPa m with an SD of 0.37 MPa m and 2.20 MPa m with an SD of 0.53 MPa m, respectively. The value of KIIc for both graphite grades was similar, although the scatter was large. In this work we found the ratio of KIIc/KIc ≈ 1.6. .« less

  4. Method of forming impermeable carbide coats on graphite

    DOE Patents [OSTI]

    Wohlberg, C.

    1973-12-11

    A method of forming an impermeable refractory metal carbide coating on graphite is described in which a metal containing oxidant and a carbide former are applied to the surface of the graphite, heated to a temperature of between 1200 and 1500 deg C in an inert gas, under a vacuum and continuing to heat to about 2300 deg C. (Official Gazette)

  5. Pyrotek Graphitization Facility Expansion Project | Department of Energy

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

    1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon arravt016_es_sekedat_2011_p.pdf More Documents & Publications Pyrotek Graphitization Facility Expansion Project Pyrotek Graphitization Facility Expansion Project EA-1720: Finding of No Significant Impact

  6. Carbon Characterization Laboratory Readiness to Receive Irradiated Graphite Samples

    SciTech Connect (OSTI)

    Karen A. Moore

    2011-05-01

    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.

  7. Removal of 14C from Irradiated Graphite for Graphite Recycle and Waste Volume Reduction

    SciTech Connect (OSTI)

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

    2014-06-10

    The aim of the research presented here was to identify the chemical form of 14C in irradiated 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. Approximately 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 14C, with a half-life of 5730 years.

  8. Effects of Oxidation on Oxidation-Resistant Graphite

    SciTech Connect (OSTI)

    Windes, William; Smith, Rebecca; Carroll, Mark

    2015-05-01

    The Advanced Reactor Technology (ART) Graphite Research and Development Program is investigating doped nuclear graphite grades that exhibit oxidation resistance through the formation of protective oxides on the surface of the graphite material. In the unlikely event of an oxygen ingress accident, graphite components within the VHTR core region are anticipated to oxidize so long as the oxygen continues to enter the hot core region and the core temperatures remain above 400C. For the most serious air-ingress accident which persists over several hours or days the continued oxidation can result in significant structural damage to the core. Reducing the oxidation rate of the graphite core material during any air-ingress accident would mitigate the structural effects and keep the core intact. Previous air oxidation testing of nuclear-grade graphite doped with varying levels of boron-carbide (B4C) at a nominal 739C was conducted for a limited number of doped specimens demonstrating a dramatic reduction in oxidation rate for the boronated graphite grade. This report summarizes the conclusions from this small scoping study by determining the effects of oxidation on the mechanical strength resulting from oxidation of boronated and unboronated graphite to a 10% mass loss level. While the B4C additive did reduce mechanical strength loss during oxidation, adding B4C dopants to a level of 3.5% or more reduced the as-fabricated compressive strength nearly 50%. This effectively minimized any benefits realized from the protective film formed on the boronated grades. Future work to infuse different graphite grades with silicon- and boron-doped material as a post-machining conditioning step for nuclear components is discussed as a potential solution for these challenges in this report.

  9. Recent developments in graphite. [Use in HTGR and aerospace

    SciTech Connect (OSTI)

    Cunningham, J.E.

    1983-01-01

    Overall, the HTGR graphite situation is in excellent shape. In both of the critical requirements, fuel blocks and support structures, adequate graphites are at hand and improved grades are sufficiently far along in truncation. In the aerospace field, GraphNOL N3M permits vehicle performance with confidence in trajectories unobtainable with any other existing material. For fusion energy applications, no other graphite can simultaneously withstand both extreme thermal shock and neutron damage. Hence, the material promises to create new markets as well as to offer a better candidate material for existing applications.

  10. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions in Graphite First Direct Evidence of Dirac Fermions in Graphite Print Wednesday, 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute

  11. One approach to artificial photosynthesis

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

    Authors: Llansola-Portols, M.J., Palacios, R.E., Kodis, G., Megiatto, J.D., Moore, A.L., Moore, T. A., and Gust, D. Title: One approach to artificial photosynthesis...

  12. Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report

    SciTech Connect (OSTI)

    Bruce G. Schnitzler

    2012-01-01

    Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse ({approx}900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal alloy fuel types were pursued. The primary and significantly larger Rover/NERVA program focused on graphite type fuels. Research, development, and testing of high temperature graphite fuels was conducted. Reactors and engines employing these fuels were designed, built, and ground tested. The GE-710 and ANL programs focused on an alternative ceramic-metallic 'cermet' fuel type consisting of UO2 (or UN) fuel embedded in a refractory metal matrix such as tungsten. The General Electric program examined closed loop concepts for space or terrestrial applications as well as open loop systems for direct nuclear thermal propulsion. Although a number of fast spectrum reactor and engine designs suitable for direct nuclear thermal propulsion were proposed and designed, none were built. This report summarizes status results of evaluations of small nuclear reactor designs suitable for direct nuclear thermal propulsion.

  13. Graphite fiber as a positive electrode of rechargeable lithium cells

    SciTech Connect (OSTI)

    Matsuda, Y.; Katsuma, H.; Morita, M.

    1984-01-01

    Graphite compounds have gained interest as possible positive electrodes for rechargeable lithium cells. Their charge-discharge characteristics have been studied in organic electrolytic solutions such as sulfolane dimethylsulfite, and propylene carbonate.

  14. Understanding Interfaces in Metal-Graphitic Hybrid Nanostructures

    SciTech Connect (OSTI)

    Ding, Mengning; Tang, Yifan; Star, Alexander

    2013-01-03

    Metalgraphitic interfaces formed between metal nanoparticles (MNPs) and carbon nanotubes (CNTs) or graphene play an important role in the properties of such hybrid nanostructures. This Perspective summarizes different types of interfaces that exist within the metalcarbon nanoassemblies and discusses current efforts on understanding and modeling the interfacial conditions and interactions. Characterization of the metalgraphitic interfaces is described here, including microscopy, spectroscopy, electrochemical techniques, and electrical measurements. Recent studies on these nanohybrids have shown that the metalgraphitic interfaces play critical roles in both controlled assembly of nanoparticles and practical applications of nanohybrids in chemical sensors and fuel cells. Better understanding, design, and manipulation of metalgraphitic interfaces could therefore become the new frontier in the research of MNP/CNT or MNP/graphene hybrid systems.

  15. Aluminum for bonding Si-Ge alloys to graphite

    DOE Patents [OSTI]

    Eggemann, Robert V.

    1976-01-13

    Improved thermoelectric device and process, comprising the high-temperature, vacuum bonding of a graphite contact and silicon-germanium thermoelectric element by the use of a low void, aluminum, metallurgical shim with low electrical resistance sandwiched therebetween.

  16. Brookhaven Lab Completes Decommissioning of Graphite Research Reactor:

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

    Reactor core and associated structures successfully removed; waste shipped offsite for disposal | Department of Energy Brookhaven Lab Completes Decommissioning of Graphite Research Reactor: Reactor core and associated structures successfully removed; waste shipped offsite for disposal Brookhaven Lab Completes Decommissioning of Graphite Research Reactor: Reactor core and associated structures successfully removed; waste shipped offsite for disposal September 1, 2012 - 12:00pm Addthis The

  17. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger

  18. GUM Analysis for TIMS and SIMS Isotopic Ratios in Graphite

    SciTech Connect (OSTI)

    Heasler, Patrick G.; Gerlach, David C.; Cliff, John B.; Petersen, Steven L.

    2007-04-01

    This report describes GUM calculations for TIMS and SIMS isotopic ratio measurements of reactor graphite samples. These isotopic ratios are used to estimate reactor burn-up, and currently consist of various ratios of U, Pu, and Boron impurities in the graphite samples. The GUM calculation is a propagation of error methodology that assigns uncertainties (in the form of standard error and confidence bound) to the final estimates.

  19. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger

  20. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger

  1. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger

  2. First Direct Evidence of Dirac Fermions in Graphite

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

    Direct Evidence of Dirac Fermions 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 driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger

  3. Graphitic biocarbon from metal-catalyzed hydrothermal carbonization of lignin

    SciTech Connect (OSTI)

    Demir, Muslum; Kahveci, Zafer; Aksoy, Burak; Palapati, Naveen K. R.; Subramanian, Arunkumar; Cullinan, Harry T.; El-Kaderi, Hani M.; Harris, Charles T.; Gupta, Ram B.

    2015-10-09

    Lignin is a high-volume byproduct from the pulp and paper industry and is currently burned to generate electricity and process heat. Moreover, the industry has been searching for high value-added uses of lignin to improve the process economics. In addition, battery manufacturers are seeking nonfossil sources of graphitic carbon for environmental sustainability. In our work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce biochar, which is then graphitized using a metal nitrate catalyst at 900–1100 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts—iron, cobalt, and manganese nitrates—is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was obtained using catalysis by Mn(NO3)2 at 900 °C and Co(NO3)2 at 1100 °C.

  4. Graphitic biocarbon from metal-catalyzed hydrothermal carbonization of lignin

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

    Demir, Muslum; Kahveci, Zafer; Aksoy, Burak; Palapati, Naveen K. R.; Subramanian, Arunkumar; Cullinan, Harry T.; El-Kaderi, Hani M.; Harris, Charles T.; Gupta, Ram B.

    2015-10-09

    Lignin is a high-volume byproduct from the pulp and paper industry and is currently burned to generate electricity and process heat. Moreover, the industry has been searching for high value-added uses of lignin to improve the process economics. In addition, battery manufacturers are seeking nonfossil sources of graphitic carbon for environmental sustainability. In our work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce biochar, which is then graphitized using a metal nitratemore » catalyst at 900–1100 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts—iron, cobalt, and manganese nitrates—is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was obtained using catalysis by Mn(NO3)2 at 900 °C and Co(NO3)2 at 1100 °C.« less

  5. Feasibility of monitoring the strength of HTGR core support graphite: Part III

    SciTech Connect (OSTI)

    Morgan, W.C.; Davis, T.J.; Thomas, M.T.

    1983-02-01

    Methods are being developed to monitor, in-situ, the strength changes of graphite core-support components in a High-Temperature Gas-Cooled Reactor (HTGR). The results reported herein pertain to the development of techniques for monitoring the core-support blocks; the PGX graphite used in these studies is the grade used for the core-support blocks of the Fort St. Vrain HTGR, and is coarser-grained than the grades used in our previous investigations. The through-transmission ultrasonic velocity technique, developed for monitoring strength of the core-support posts, is not suitable for use on the core-support blocks. Eddy-current and ultrasonic backscattering techniques have been shown to be capable of measuring the density-depth profile in oxidized PGX and, combined with a correlation of strength versus density, could yield an estimate of the strength-depth profile of in-service HTGR core support blocks. Correlations of strength versus density and other properties, and progress on the development of the eddy-current and ultrasonic backscattering techniques are reported.

  6. Joint Center for Artificial Photosynthesis

    ScienceCinema (OSTI)

    Koval, Carl; Lee, Kenny; Houle, Frances; Lewis, Nate

    2013-12-19

    The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP brings together more than 140 top scientists and researchers from the California Institute of Technology and its lead partner, Berkeley Lab, along with collaborators from the SLAC National Accelerator Laboratory, and the University of California campuses at Irvine and San Diego.

  7. Method for wetting a boron alloy to graphite

    DOE Patents [OSTI]

    Storms, E.K.

    1987-08-21

    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.

  8. Artificial Solid Electrolyte Interphase to Address the Electrochemical Degradation of Silicon Electrodes

    SciTech Connect (OSTI)

    Dudney, Nancy J; Nanda, Jagjit; Liang, Chengdu; Li, Juchuan

    2014-01-01

    Electrochemical degradation on Si anodes prevents them from being successfully used in lithium-ion full cells. Unlike the case of graphite anodes, natural solid electrolyte interphase (SEI) films generated from carbonate electrolyte do not self-passivate on Si and causes continuous electrolyte decomposition. In this work we aim at solving the issue of electrochemical degradation by fabricating artificial SEI films using a solid electrolyte material, lithium phosphor oxynitride (Lipon), that conducts Li ions and blocks electrons. For Si anodes coated with Lipon of 50 nm or thicker, significant effect is observed in suppressing the electrolyte decomposition, while Lipon of thinner than 40 nm has little effect. Ionic and electronic conductivity measurement reveals that the artificial SEI is effective when it is a pure ionic conductor, and the electrolyte decomposition is not suppressed when the artificial SEI is a mixed electronic-ionic conductor. The critical thickness for this transition in conducting behavior is found to be 40~50 nm. This work provides guidance for designing artificial SEI for high capacity lithium-ion battery electrodes using solid electrolyte materials.

  9. Graphitization of polymer surfaces by scanning ion irradiation

    SciTech Connect (OSTI)

    Koval, Yuri [Department of Physics, Universitt Erlangen-Nrnberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany)

    2014-10-20

    Graphitization of polymer surfaces was performed by low-energy Ar{sup +} and He{sup +} ion irradiation. A method of scanning irradiation was implemented. It was found that by scanning ion irradiation, a significantly higher electrical conductivity in the graphitized layers can be achieved in comparison with a conventional broad-beam irradiation. The enhancement of the conductance becomes more pronounced for narrower and better collimated ion beams. In order to analyze these results in more detail, the temperature dependence of conductance of the irradiated samples was investigated. The results of measurements are discussed in terms of weak localization corrections to conductance in disordered metals. The observed effects can be explained by enlargement of graphitic patches, which was achieved with the scanning ion irradiation method.

  10. Artificial photosynthesis combines biology with technology for...

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

    Artificial photosynthesis combines biology with technology for sustainable energy ... photosynthetic net primary production (NPP) to support our GDP and nutrition. ...

  11. Agronomic Suitability of Bioenergy Crops in Mississippi

    SciTech Connect (OSTI)

    Lemus, Rocky; Baldwin, Brian; Lang, David

    2011-10-01

    In Mississippi, some questions need to be answered about bioenergy crops: how much suitable land is available? How much material can that land produce? Which production systems work best in which scenarios? What levels of inputs will be required for productivity and longterm sustainability? How will the crops reach the market? What kinds of infrastructure will be necessary to make that happen? This publication helps answer these questions: • Which areas in the state are best for bioenergy crop production? • How much could these areas produce sustainably? • How can bioenergy crops impact carbon sequestration and carbon credits? • How will these crops affect fertilizer use and water quality? • What kind of water management is needed to maintain a productive crop? The answers to these questions will help supporting institutions across the state to improve land assessment and agronomic management practices for biomass production. In the last decade, energy supply has become a worldwide problem. Bioenergy crops could supply energy in the future. Bioenergy crops are plants, usually perennial grasses and trees, that produce a lot of biomass that can be converted into energy. Bioenergy crops can be grown for two energy markets: power generation, such as heat and electricity, or liquid fuel, such as cellulosic ethanol. These resources could reduce petroleum dependency and greenhouse gas production. Woody plants and herbaceous warm-season grasses, such as switchgrass, giant miscanthus,energy cane, and high yielding sorghums, could be major sources of biomass in Mississippi.

  12. Graphite fiber reinforced structure for supporting machine tools

    DOE Patents [OSTI]

    Knight, Jr., Charles E.; Kovach, Louis; Hurst, John S.

    1978-01-01

    Machine tools utilized in precision machine operations require tool support structures which exhibit minimal deflection, thermal expansion and vibration characteristics. The tool support structure of the present invention is a graphite fiber reinforced composite in which layers of the graphite fibers or yarn are disposed in a 0/90.degree. pattern and bonded together with an epoxy resin. The finished composite possesses a low coefficient of thermal expansion and a substantially greater elastic modulus, stiffness-to-weight ratio, and damping factor than a conventional steel tool support utilized in similar machining operations.

  13. Early Damage Mechanisms in Nuclear Grade Graphite under Irradiation

    SciTech Connect (OSTI)

    Eapen, Dr. Jacob [North Carolina State University] [North Carolina State University; Krishna, Dr Ram [North Carolina State University] [North Carolina State University; Burchell, Timothy D [ORNL] [ORNL; Murty, Prof K.L. [North Carolina State University] [North Carolina State University

    2014-01-01

    Using Raman and X-ray photoelectron spectroscopy,we delineate the bond and defect structures in nuclear block graphite (NBG-18) under neutron and ion irradiation. The strengthening of the defect (D) peak in the Raman spectra under irradiation is attributed to an increase in the topological, sp2-hybridized defects. Using transmission electron microscopy, we provide evidence for prismatic dislocations as well as a number of basal dislocations dissociating into Shockley partials. The non-vanishing D peak in the Raman spectra, together with a generous number of dislocations, even at low irradiation doses, indicates a dislocation-mediated amorphization process in graphite.

  14. Gelcasting polymeric precursors for producing net-shaped graphites

    DOE Patents [OSTI]

    Klett, James W.; Janney, Mark A.

    2005-02-15

    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.

  15. Gelcasting polymeric precursors for producing net-shaped graphites

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  16. High strength graphite and method for preparing same

    DOE Patents [OSTI]

    Overholser, Lyle G.; Masters, David R.; Napier, John M.

    1976-01-01

    High strength graphite is manufactured from a mixture of a particulate filler prepared by treating a particulate carbon precursor at a temperature in the range of about 400.degree. to 1000.degree. C., an organic carbonizable binder, and green carbonizable fibers in a concentration of not more than 2 weight per cent of the filler. The use of the relatively small quantity of green fibers provides a substantial increase in the flexural strength of the graphite with only a relatively negligible increase in the modulus of elasticity.

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

    DOE Patents [OSTI]

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

    1989-01-01

    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.

  18. Analysis of a graphite foam-NaCl latent heat storage system for...

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

    Analysis of a graphite foam-NaCl latent heat storage system for supercritical CO2 power cycles for concentrated solar power Title Analysis of a graphite foam-NaCl latent heat...

  19. Artificial leaf jumps developmental hurdle

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

    Center Objective The Science Center Publications Graduate Research opportunities Undergraduate research opportunities EFRC-501 graduate class Seminar schedules Center News Research Highlights Center Research News Media about Center Center Video Library Bisfuel Picture Gallery Artificial leaf jumps developmental hurdle 18 Feb 2014 by Jenny Green: In a recent early online edition of Nature Chemistry, ASU scientists, along with colleagues at Argonne National Laboratory, have reported advances

  20. Solar Fuels via Artificial Photosynthesis

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

    Solar Fuels via Artificial Photosynthesis 24 Aug 2010 Devens Gust, Thomas Moore and Ana Moore are the authors of one of 10 Most-Accessed Articles from one of the Highest Impact Journals in Multidisciplinary Chemistry. Because sunlight is diffuse and intermittent, substantial use of solar energy to meet humanity's needs will probably require energy storage in dense, transportable media via chemical bonds. Practical, cost effective technologies for conversion of sunlight directly into useful fuels

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

    SciTech Connect (OSTI)

    Robert L. Bratton; Tim D. Burchell

    2005-08-01

    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.

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

    SciTech Connect (OSTI)

    Robert Bratton

    2010-06-01

    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.

  3. Method of coating graphite tubes with refractory metal carbides

    DOE Patents [OSTI]

    Wohlberg, C.

    1973-12-11

    A method of coating graphite tubes with a refractory metal carbide is described. An alkali halide is reacted with a metallic oxide, the metallic portion being selected from the IVth or Vth group of the Periodic Table, the resulting salt reacting in turn with the carbon to give the desired refractory metal carbide coating. (Official Gazette)

  4. Solid Lithium Ion Conducting Electrolytes Suitable for Manufacturing...

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

    Lithium Ion Conducting Electrolytes Suitable for Manufacturing Processes Oak Ridge National Laboratory Contact ORNL About This Technology Technology Marketing SummaryThe lithium ...

  5. AMO Requests Technical Topics Suitable for a Manufacturing Innovation...

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

    Innovation Institute AMO Requests Technical Topics Suitable for a Manufacturing Innovation Institute April 17, 2014 - 12:23pm Addthis The Advanced Manufacturing Office...

  6. High elastic modulus polymer electrolytes suitable for preventing...

    Office of Scientific and Technical Information (OSTI)

    in lithium batteries Citation Details In-Document Search Title: High elastic modulus polymer electrolytes suitable for preventing thermal runaway in lithium batteries A polymer ...

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

    DOE Patents [OSTI]

    Makowiecki, Daniel M.; Ramsey, Philip B.; Juntz, Robert S.

    1995-01-01

    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.

  8. Suitability, Position Sensitivity Designations, and Related Personnel Matters

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1989-12-19

    The order identifies the interrelationships among suitability, security and access authorizations; to establish guidance and policy regarding position sensitivity designations, certain background investigations, and suitability determinations; and to establish the policies and procedures regarding waivers of pre-employment investigations. Chg 1, dated 7-8-92 supersedes DOE 3731.1.

  9. Recovery of flake graphite from steelmaking kish. Report of investigations/1994

    SciTech Connect (OSTI)

    Laverty, P.D.; Nicks, L.J.; Walters, L.A.

    1994-01-01

    As part of its research efforts to encourage conservation and reuse of natural resources, the Bureau of Mines has developed a processing method to produce high-quality flake graphite from the steelmaking waste known as kish. The kish produced by current steelmaking practices is a mixture of graphite, desulfurization slag, and iron that is skimmed from the molten iron feed to the basic oxygen furnace. It is estimated that the graphite content of kish discarded by American steel plants is more than sufficient to meet the total U.S. demand for flake graphite. That need is now filled by natural graphite from foreign sources. Kish was treated by a combination of screening and hydraulic classification to produce a concentrate containing greater than 70 pct graphite. Leaching of the concentrate with hydrochloric acid solution gave a graphite product with 95 pct purity.

  10. Artificial Muscle Inc | Open Energy Information

    Open Energy Info (EERE)

    Inc Place: California Zip: CA 94085 Product: Artificial Muscle develops electroactive polymer technology used for sensing, actuating and electric power generation applications....

  11. Carbon K-Edge XANES Spectromicroscopy of Natural Graphite

    SciTech Connect (OSTI)

    Brandes,J.; Cody, G.; Rumble, D.; Haberstroh, P.; Wirick, S.; Gelinas, Y.; Morais-Cabral, J.

    2008-01-01

    The black carbon continuum is composed of a series of carbon-rich components derived from combustion or metamorphism and characterized by contrasting environmental behavior and susceptibility to oxidation. In this work, we present a micro-scale density fractionation method that allows isolating the small quantities of soot-like and graphitic material usually found in natural samples. Organic carbon and {delta}{sup 13}C mass balance calculations were used to quantify the relative contributions of the two fractions to thermally-stable organic matter from a series of aquatic sediments. Varying proportions of soot-like and graphitic material were found in these samples, with large variations in {delta}{sup 13}C signatures suggesting important differences in their origin and/or dynamics in the environment.

  12. 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.

    2000-05-02

    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.

  13. Graphite and its Hidden Superconductivity | Stanford Synchrotron Radiation

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

    Lightsource powders [7]. Special emphasis will be given to the possible ways to differentiate between ferromagnetic- from superconducting-like signals when the magnetic moments of interest remain small in comparison with the large diamagnetic backgrounds. Recently done transport and persistent currents experiments at room temperature on graphite flakes embedded in alkanes and their reproducibility. All the experimental evidence as a whole suggests the existence of superconductivity at very

  14. Graphitized Conductive Carbon Coatings for Composite Electrodes - Energy

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

    Innovation Portal Energy Storage Energy Storage Advanced Materials Advanced Materials Find More Like This Return to Search Graphitized Conductive Carbon Coatings for Composite Electrodes Lawrence Berkeley National Laboratory Contact LBL About This Technology Technology Marketing SummaryRobert Kostecki and Marek Marcinek of Lawrence Berkeley National Laboratory have developed a method to improve the performance and operational life of composite electrodes by direct deposition of a continuous,

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

    DOE Patents [OSTI]

    Kennedy, Charles R.

    1980-01-01

    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.

  16. METAL ALLOY SUITABLE FOR CONTROLLING THERMAL NEUTRON REACTORS

    DOE Patents [OSTI]

    Schier, R.J.

    1963-11-26

    A homogeneous arc-melted alloy suitable for nuclear reactor control material consisting essentially of titanium and up to about 8 wt% gadolinium as gadolinium oxide is described. (AEC)

  17. Assessment of Small Modular Reactor Suitability for Use On or...

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

    This report assesses the suitability of using US-developed light water SMR technology to provide energy for Schriever Air Force Base, CO and Clear Air Force Station, AK, as well as ...

  18. High elastic modulus polymer electrolytes suitable for preventing thermal

    Office of Scientific and Technical Information (OSTI)

    runaway in lithium batteries (Patent) | SciTech Connect electrolytes suitable for preventing thermal runaway in lithium batteries Citation Details In-Document Search Title: High elastic modulus polymer electrolytes suitable for preventing thermal runaway in lithium batteries A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not

  19. Mapping suitability areas for concentrated solar power plants using remote

    Office of Scientific and Technical Information (OSTI)

    sensing data (Journal Article) | DOE PAGES DOE PAGES Search Results Accepted Manuscript: Mapping suitability areas for concentrated solar power plants using remote sensing data Title: Mapping suitability areas for concentrated solar power plants using remote sensing data The political push to increase power generation from renewable sources such as solar energy requires knowing the best places to site new solar power plants with respect to the applicable regulatory, operational, engineering,

  20. Request for Information (RFI): Clean Energy Manufacturing Topics Suitable

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

    for a Manufacturing Innovation Institute | Department of Energy Clean Energy Manufacturing Topics Suitable for a Manufacturing Innovation Institute Request for Information (RFI): Clean Energy Manufacturing Topics Suitable for a Manufacturing Innovation Institute April 17, 2014 - 11:04am Addthis Funding: This RFI is not a Funding Opportunity Announcement (FOA); therefore, EERE is not accepting applications at this time. Open Date: 04/17/2014 Close Date: 05/20/2014 Funding Organization: The

  1. Conformationally Constrained Macrocyclic Diporphyrin-Fullerene Artificial

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

    Photosynthetic Reaction Center Conformationally Constrained Macrocyclic Diporphyrin-Fullerene Artificial Photosynthetic Reaction Center Authors: Garg, V., Kodis, G., Chachisvilis, M., Hambourger, M., Moore, A. L., Moore, T. A., and Gust, D. Title: Conformationally Constrained Macrocyclic Diporphyrin-Fullerene Artificial Photosynthetic Reaction Center Source: Journal of the American Chemical Society Year: 2011 Volume: 133 Pages: 2944-2954 ABSTRACT: Photosynthetic reaction centers convert

  2. High temperature gas-cooled reactor (HTGR) graphite pebble fuel: Review of technologies for reprocessing

    SciTech Connect (OSTI)

    Mcwilliams, A. J.

    2015-09-08

    This report reviews literature on reprocessing high temperature gas-cooled reactor graphite fuel components. A basic review of the various fuel components used in the pebble bed type reactors is provided along with a survey of synthesis methods for the fabrication of the fuel components. Several disposal options are considered for the graphite pebble fuel elements including the storage of intact pebbles, volume reduction by separating the graphite from fuel kernels, and complete processing of the pebbles for waste storage. Existing methods for graphite removal are presented and generally consist of mechanical separation techniques such as crushing and grinding chemical techniques through the use of acid digestion and oxidation. Potential methods for reprocessing the graphite pebbles include improvements to existing methods and novel technologies that have not previously been investigated for nuclear graphite waste applications. The best overall method will be dependent on the desired final waste form and needs to factor in the technical efficiency, political concerns, cost, and implementation.

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

    DOE Patents [OSTI]

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

    1995-07-04

    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.

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

    SciTech Connect (OSTI)

    Eapen, Jacob; Murty, Korukonda; Burchell, Timothy

    2014-06-02

    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.

  5. Kinetics of Chronic Oxidation of NBG-17 Nuclear Graphite by Water Vapor

    SciTech Connect (OSTI)

    Contescu, Cristian I; Burchell, Timothy D; Mee, Robert

    2015-05-01

    This report presents the results of kinetic measurements during accelerated oxidation tests of NBG-17 nuclear graphite by low concentration of water vapor and hydrogen in ultra-high purity helium. The objective is to determine the parameters in the Langmuir-Hinshelwood (L-H) equation describing the oxidation kinetics of nuclear graphite in the helium coolant of high temperature gas-cooled reactors (HTGR). Although the helium coolant chemistry is strictly controlled during normal operating conditions, trace amounts of moisture (predictably < 0.2 ppm) cannot be avoided. Prolonged exposure of graphite components to water vapor at high temperature will cause very slow (chronic) oxidation over the lifetime of graphite components. This behavior must be understood and predicted for the design and safe operation of gas-cooled nuclear reactors. The results reported here show that, in general, oxidation by water of graphite NBG-17 obeys the L-H mechanism, previously documented for other graphite grades. However, the characteristic kinetic parameters that best describe oxidation rates measured for graphite NBG-17 are different than those reported previously for grades H-451 (General Atomics, 1978) and PCEA (ORNL, 2013). In some specific conditions, certain deviations from the generally accepted L-H model were observed for graphite NBG-17. This graphite is manufactured in Germany by SGL Carbon Group and is a possible candidate for the fuel elements and reflector blocks of HTGR.

  6. Method of fabricating graphite for use as a skeletal prosthesis and product thereof

    DOE Patents [OSTI]

    Eatherly, Walter P.; Robbins, J. M.; Rosson, Sr., David E.

    1978-01-01

    A method for producing porous graphite for use as bone replacement with a structure for osteon penetration. Graphite is produced with ordered circular pores of 100 to 1000 microns in diameter covering at least 25% of the exposed surfaces. A cylindrical fiber is coated with a carbon flour-pitch mix and is then wound on a bobbin in a predetermined manner. The product of winding is dried, pressed, carbonized, and then graphitized. The fibers are removed either chemically or by volatilization during carbonization or graphitization.

  7. Photo of the Week: The Brookhaven Graphite Research Reactor | Department of

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

    Energy The Brookhaven Graphite Research Reactor Photo of the Week: The Brookhaven Graphite Research Reactor May 30, 2014 - 1:12pm Addthis The Brookhaven Graphite Research Reactor (BGRR) was the first reactor built in the U.S. for peacetime atomic research following World War II. Over 18 years, an estimated 25,000 scientific experiments were carried out using the neutrons produced in the facility's 700-ton graphite core. In addition to advancing the understanding of atomic nuclei and the

  8. Tunable Graphitic Carbon Nano-Onions Development in Carbon Nanofibers for Multivalent Energy Storage

    SciTech Connect (OSTI)

    Schwarz, Haiqing L.

    2016-01-01

    We developed a novel porous graphitic carbon nanofiber material using a synthesis strategy combining electrospinning and catalytic graphitization. RF hydrogel was used as carbon precursors, transition metal ions were successfully introduced into the carbon matrix by binding to the carboxylate groups of a resorcinol derivative. Transition metal particles were homogeneously distributed throughout the carbon matrix, which are used as in-situ catalysts to produce graphitic fullerene-like nanostructures surrounding the metals. The success design of graphitic carbons with enlarged interlayer spacing will enable the multivalent ion intercalation for the development of multivalent rechargeable batteries.

  9. Zhejiang DunAn Artificial Environmental Equipment Co Ltd | Open...

    Open Energy Info (EERE)

    DunAn Artificial Environmental Equipment Co Ltd Jump to: navigation, search Name: Zhejiang DunAn Artificial Environmental Equipment Co Ltd Place: Zhuji, Zhejiang Province, China...

  10. Artificial oxygen transport protein (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Patent: Artificial oxygen transport protein Citation Details In-Document Search Title: Artificial oxygen transport protein This invention provides heme-containing peptides capable...

  11. Real and effective thermal equilibrium in artificial square spin...

    Office of Scientific and Technical Information (OSTI)

    Real and effective thermal equilibrium in artificial square spin ices Citation Details In-Document Search Title: Real and effective thermal equilibrium in artificial square spin ...

  12. Artificial Photosynthesis: An Alternative to Fuel Cell Development...

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

    Artificial Photosynthesis: An Alternative to Fuel Cell Development December 15, 2015 Artificial Photosynthesis: An Alternative to Fuel Cell Development Photosynthesis research at ...

  13. Artificial Lift Technology | GE Global Research

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

    Technology: Driving the Artificial Lift Market Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new window) Click to share on LinkedIn (Opens in new window) Click to share on Tumblr (Opens in new window) Technology: Driving the Artificial Lift Market Gary Ford, president and CEO of GE Artificial Lift, discusses what the equipment does, the current state of the market and the importance of working with GE's Global Research

  14. Method of fabricating silicon carbide coatings on graphite surfaces

    DOE Patents [OSTI]

    Varacalle, Jr., Dominic J.; Herman, Herbert; Burchell, Timothy D.

    1994-01-01

    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.

  15. Method of fabricating silicon carbide coatings on graphite surfaces

    DOE Patents [OSTI]

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

    1994-07-26

    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.

  16. Cryogenic Thermal Expansion of Y-12 Graphite Fuel Elements

    SciTech Connect (OSTI)

    Eash, D. T.

    2013-07-08

    Thermal expansion measurements betwccn 20°K and 300°K were made on segments of three uranium-loaded Y-12 uncoated graphite fuel elements. The thermal expansion of these fuel elements over this temperature range is represented by the equation: {Delta}L/L = -39.42 x 10{sup -5} + 1.10 x 10{sup -7} T + 6.47 x 10{sup -9} T{sup 2} - 8.30 x 10{sup -12} T{sup 3}.

  17. Exploration of Artificial Frustrated Magnets

    SciTech Connect (OSTI)

    Samarth, Nitin; Schiffer, Peter

    2015-02-17

    This program encompasses experimental and theoretical studies of arrays of nanometer-scale magnets known as “artificial frustrated magnets”. These magnets are small and closely spaced, so that their behavior as a collective group is complex and reveals insights into how such collections of interacting objects behave as a group. In particular, the placement of the magnets is such that the interactions between them are “frustrated”, in that they compete with each other. These systems are analogs to a class of magnetic materials in which the lattice geometry frustrates interactions between individual atomic moments, and in which a wide range of novel physical phenomena have been recently observed. The advantage to studying the arrays is that they are both designable and resolvable: i.e., the experiments can control all aspects of the array geometry, and can also observe how individual elements of the arrays behave. This research program demonstrated a number of phenomena including the role of multiple collective interactions, the feasibility of using systems with their magnetism aligned perpendicular to the plane of the array, the importance of disorder in the arrays, and the possibility of using high temperatures to adjust the magnet orientations. All of these phenomena, and others explored in this program, add to the body of knowledge around collective magnetic behavior and magnetism in general. Aside from building scientific knowledge in an important technological area, with relevance to computing and memory, the program also gave critical support to the education of students working on the experiments.

  18. Suitability for 3D Printed Parts for Laboratory Use

    SciTech Connect (OSTI)

    Zwicker, Andrew P.; Bloom, Josh; Albertson, Robert; Gershman, Sophia

    2014-08-01

    3D printing has become popular for a variety of users, from industrial to the home hobbyist, to scientists and engineers interested in producing their own laboratory equipment. In order to determine the suitability of 3D printed parts for our plasma physics laboratory, we measured the accuracy, strength, vacuum compatibility, and electrical properties of pieces printed in plastic. The flexibility of rapidly creating custom parts has led to the 3D printer becoming an invaluable resource in our laboratory and is equally suitable for producing equipment for advanced undergraduate laboratories.

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

    SciTech Connect (OSTI)

    Strizak, Joe P; Burchell, Timothy D; Windes, Will

    2011-12-01

    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.

  20. Carotenoid Photoprotection in Artificial Photosynthetic Antennas

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

    Carotenoid Photoprotection in Artificial Photosynthetic Antennas Authors: Kloz, M., Pillai, S., Kodis, G., Gust, D., Moore, T. A., Moore, A. L., van Grondelle, R., and Kennis, J. T. M. Title: Carotenoid Photoprotection in Artificial Photosynthetic Antennas Source: Journal of the American Chemical Society Year: 2011 Volume: 133 Pages: 7007-7015 ABSTRACT: A series of phthalocyanine-carotenoid dyads in which a phenylamino group links a phthalocyanine to carotenoids having 8-11 backbone double bonds

  1. Fully Integrated Nanosystem for Artificial Photosynthesis - Energy

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

    Innovation Portal Advanced Materials Advanced Materials Find More Like This Return to Search Fully Integrated Nanosystem for Artificial Photosynthesis Lawrence Berkeley National Laboratory Contact LBL About This Technology Publications: PDF Document Publication Liu, C., Dasgupta, N. P., Yang, P., "Semiconductor Nanowires for Artificial Photosynthesis," Chemistry of Materials, 2014, 26(1), 415-422, DOI: 10.1021/cm4023198. (1,285 KB) PDF Document Publication Liu, C., Tang, J., Chen,

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

    DOE Patents [OSTI]

    Zidan, Ragaiy; Ritter, James A.; Ebner, Armin D.; Wang, Jun; Holland, Charles E.

    2008-06-10

    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.

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

    SciTech Connect (OSTI)

    Carroll, Mark C

    2014-09-01

    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.

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

    SciTech Connect (OSTI)

    Peng, W.; Yang, X. Y.; Yu, S. Y.; Wang, J.

    2012-07-01

    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)

  5. Effects of Stone-Wales and vacancy defects in atomic-scale friction on defective graphite

    SciTech Connect (OSTI)

    Sun, Xiao-Yu; Wu, RunNi; Xia, Re; Chu, Xi-Hua; Xu, Yuan-Jie

    2014-05-05

    Graphite is an excellent solid lubricant for surface coating, but its performance is significantly weakened by the vacancy or Stone-Wales (SW) defect. This study uses molecular dynamics simulations to explore the frictional behavior of a diamond tip sliding over a graphite which contains a single defect or stacked defects. Our results suggest that the friction on defective graphite shows a strong dependence on defect location and type. The 5-7-7-5 structure of SW defect results in an effectively negative slope of friction. For defective graphite containing a defect in the surface, adding a single vacancy in the interior layer will decrease the friction coefficients, while setting a SW defect in the interior layer may increase the friction coefficients. Our obtained results may provide useful information for understanding the atomic-scale friction properties of defective graphite.

  6. Comparison of Prime Movers Suitable for USMC Expeditionary Power Sources

    SciTech Connect (OSTI)

    Theiss, T.J.

    2000-04-18

    This report documents the results of the ORNL investigation into prime movers that would be desirable for the construction of a power system suitable for the United States Marine Corps (USMC) expeditionary forces under Operational Maneuvers From The Sea (OMFTS) doctrine. Discrete power levels of {approx}1, 5, 15, and 30 kW are considered. The only requirement is that the prime mover consumes diesel fuel. A brief description is given for the prime movers to describe their basic scientific foundations and relative advantages and disadvantages. A list of key attributes developed by ORNL has been weighted by the USMC to indicate the level of importance. A total of 14 different prime movers were scored by ORNL personnel in four size ranges (1,5, 15, & 30 kW) for their relative strength in each attribute area. The resulting weighted analysis was used to indicate which prime movers are likely to be suitable for USMC needs. No single engine or prime mover emerged as the clear-cut favorite but several engines scored as well or better than the diesel engine. At the higher load levels (15 & 30 kW), the results indicate that the open Brayton (gas turbine) is a relatively mature technology and likely a suitable choice to meet USMC needs. At the lower power levels, the situation is more difficult and the market alone is not likely to provide an optimum solution in the time frame desired (2010). Several prime movers should be considered for future developments and may be satisfactory; specifically, the Atkinson cycle, the open Brayton cycle (gas turbine), the 2-stroke diesel. The rotary diesel and the solid oxide fuel cell should be backup candidates. Of all these prime movers, the Atkinson cycle may well be the most suitable for this application but is an immature technology. Additional demonstrations of this engine will be conducted at ORNL. If this analysis is positive, then the performance of a generator set using this engine, the open Brayton and the 2-stroke diesel should be estimated to evaluate its potential suitability for expeditionary forces. The overriding conclusion of this effort is that we feel a suitable prime mover can be found but that the development will be technically challenging and trade-offs will be made before an optimum solution is found.

  7. KRQE News: New Mexico scientists develop tiny, artificial lung

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

    Tiny, artificial lung KRQE News: New Mexico scientists develop tiny, artificial lung New Mexico researchers are creating an artificial lung, known as PuLMo for Pulmonary Lung Model. May 12, 2016 KRQE News: New Mexico scientists develop tiny, artificial lung The PuLMo alveolar unit is readied for testing. New Mexico scientists develop tiny, artificial lung It is miniature in size but not in significance. New Mexico researchers are creating a new device to test what people are breathing into their

  8. Corrosion resistant coatings suitable for elevated temperature application

    DOE Patents [OSTI]

    Chan, Kwai S.; Cheruvu, Narayana Sastry; Liang, Wuwei

    2012-07-31

    The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.

  9. Suitable thin shell structural configurations for earth sheltered housing

    SciTech Connect (OSTI)

    Behr, R.A.

    1982-01-01

    An earth sheltered house is one whose building envelope is substantially in contact with soil, without necessarily being totally underground. Hence, it can provide the commonly sought attributes of a residence, including natural light, exterior views, and curb appeal. It also exhibits strong energy performance, lower maintenance, and good storm protection. Despite the longer-term life cycle cost advantages of earth sheltered buildings, a current hindrance to the mass market acceptance of earth sheltered housing is higher initial cost which is caused, in part, by the inability of conventional rectilinear structural systems to support economically the massive soil loads imposed on earth covered buildings. In deference to the premise that technical suitability is no guarantee of innovation acceptance in the housing industry, a survey of the nontechnical impediments to housing innovation was first undertaken. These impediment areas include: market inhibition; builder trepidations; industry constraints; and financing problems. As a result of an architectural design program written under contract for the Department of Energy, it was possible to include a rather extensive (but necessarily subjective) evaluation of the architectural potential for earth sheltered shell structures. Engineering suitability dimensions included structural effectiveness, constructability, and economy of construction for single- and double-curvature thin shell structures. Overall engineering suitability and architectural potential are deemed to be adequate, although non-engineering impediments to housing innovation appear to raise significant questions regarding the potential for mass market implementation of thin shell stuctures in earth sheltered housing.

  10. Designing a TAC thermometer from a VHTR graphite structure

    SciTech Connect (OSTI)

    Smith, James A. Kotter, Dale; Garrett, Steven L.; Ali, Randall A.

    2015-03-31

    The interior of a nuclear reactor presents a particularly harsh and challenging environment for both sensors and telemetry due to high temperatures and high fluxes of energetic and ionizing particles among the radioactive decay products. Very High Temperature Reactors are pushing the in core temperatures even higher. A unique sensing approach will be discussed to address the necessary high temperature measurements. Thermoacoustic thermometry exploits high temperatures and uses materials that are immune to the effects of ionizing radiation to create a temperature sensor that is self-powered and wireless. In addition, the form-factor for the Thermoacoustic Thermometer (TACT) can be designed to be integrated within common in-pile structures. There are no physical moving parts required for TACT and the sensor is self-powered, as it uses the nuclear fuel for its heat source. TACT data will be presented from a laboratory prototype mimicking the design necessary for a VHTR graphite structure.

  11. Note on Graphite Oxidation by Oxygen and Moisture

    SciTech Connect (OSTI)

    Wichner, Robert; Burchell, Timothy D; Contescu, Cristian I

    2009-02-01

    Simplified equations of graphite oxidation are reviewed for semi-infinite slab, finite slab, and cylinder geometries, using the principal assumptions of linearized oxidation kinetics and quasi-steady state oxidation profile. All equations are coupled to a general surface mass transfer boundary condition. The equations include those for oxidant concentration distribution, surface oxidation rate, burnoff profile, and oxidation efficiency. This review also covers some areas that may not be well recognized. The key role of the effective diffusivity is highlighted, with a brief review of measured values. The temperature-dependence of the surface oxidation rate is shown to be more complex than usually shown for the diffusion-affected zone. Assumption of linear kinetics permits ready estimation of equilibration time for development of the quasi-steady burnoff profile. In addition, approximations for the time-steady hydrogen concentration profiles are developed for the case of oxidation by H2O. All cited methods can be readily evaluated by spreadsheet calculation.

  12. Graphite fuels combustion off-gas treatment options

    SciTech Connect (OSTI)

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

    1993-03-01

    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.

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

    SciTech Connect (OSTI)

    Contescu, Cristian I; Mee, Robert; Wang, Peng; Romanova, Anna V; Burchell, Timothy D

    2014-10-01

    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.

  14. 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

    2014-04-08

    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.

  15. A safety assessment of the use of graphite in nuclear reactors licensed by the US NRC

    SciTech Connect (OSTI)

    Schweitzer, D.G.; Gurinsky, D.H.; Kaplan, E.; Sastre, C.

    1987-09-01

    This report reviews existing literature and knowledge on graphite burning and on stored energy accumulation and releases in order to assess what role, if any, a stored energy release can have in initiating or contributing to hypothetical graphite burning scenarios in research reactors. It also addresses the question of graphite ignition and self-sustained combustion in the event of a loss-of-coolant accident (LOCA). The conditions necessary to initiate and maintain graphite burning are summarized and discussed. From analyses of existing information it is concluded that only stored energy accumulations and releases below the burning temperature (650/sup 0/C) are pertinent. After reviewing the existing knowledge on stored energy it is possible to show that stored energy releases do not occur spontaneously, and that the maximum stored energy that can be released from any reactor containing graphite is a very small fraction of the energy produced during the first few minutes of a burning incident. The conclusions from these analyses are that the potential to initiate or maintain a graphite burning incident is essentially independent of the stored energy in the graphite, and depends on other factors that are unique for these reactors, research reactors, and for Fort St. Vrain. In order to have self-sustained rapid graphite oxidation in any of these reactors, certain necessary conditions of geometry, temperature, oxygen supply, reaction product removal, and a favorable heat balance must be maintained. There is no new evidence associated with either the Windscale Accident or the Chernobyl Accident that indicates a credible potential for a graphite burning accident in any of the reactors considered in this review.

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

    DOE Patents [OSTI]

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

    1983-05-05

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

    DOE Patents [OSTI]

    Shaikh, Shahid N.; Ellis, Jr., Paul E.; Lyons, James E.

    1994-01-01

    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.

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

    DOE Patents [OSTI]

    Zhang, Zhiqiang; Lockwood, Frances E.

    2008-03-25

    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.

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

    DOE Patents [OSTI]

    Shaikh, S.N.; Ellis, P.E. Jr.; Lyons, J.E.

    1994-08-02

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

  20. Next Generation Nuclear Plant Phenomena Identification and Ranking Tables (PIRTs) Volume 5: Graphite PIRTs

    SciTech Connect (OSTI)

    Burchell, Timothy D; Bratton, Rob; Marsden, Barry; Srinivasan, Makuteswara; Penfield, Scott; Mitchell, Mark; Windes, Will

    2008-03-01

    Here we report the outcome of the application of the Nuclear Regulatory Commission (NRC) Phenomena Identification and Ranking Table (PIRT) process to the issue of nuclear-grade graphite for the moderator and structural components of a next generation nuclear plant (NGNP), considering both routine (normal operation) and postulated accident conditions for the NGNP. The NGNP is assumed to be a modular high-temperature gas-cooled reactor (HTGR), either a gas-turbine modular helium reactor (GTMHR) version [a prismatic-core modular reactor (PMR)] or a pebble-bed modular reactor (PBMR) version [a pebble bed reactor (PBR)] design, with either a direct- or indirect-cycle gas turbine (Brayton cycle) system for electric power production, and an indirect-cycle component for hydrogen production. NGNP design options with a high-pressure steam generator (Rankine cycle) in the primary loop are not considered in this PIRT. This graphite PIRT was conducted in parallel with four other NRC PIRT activities, taking advantage of the relationships and overlaps in subject matter. The graphite PIRT panel identified numerous phenomena, five of which were ranked high importance-low knowledge. A further nine were ranked with high importance and medium knowledge rank. Two phenomena were ranked with medium importance and low knowledge, and a further 14 were ranked medium importance and medium knowledge rank. The last 12 phenomena were ranked with low importance and high knowledge rank (or similar combinations suggesting they have low priority). The ranking/scoring rationale for the reported graphite phenomena is discussed. Much has been learned about the behavior of graphite in reactor environments in the 60-plus years since the first graphite rectors went into service. The extensive list of references in the Bibliography is plainly testament to this fact. Our current knowledge base is well developed. Although data are lacking for the specific grades being considered for Generation IV (Gen IV) concepts, such as the NGNP, it is fully expected that the behavior of these graphites will conform to the recognized trends for near isotropic nuclear graphite. Thus, much of the data needed is confirmatory in nature. Theories that can explain graphite behavior have been postulated and, in many cases, shown to represent experimental data well. However, these theories need to be tested against data for the new graphites and extended to higher neutron doses and temperatures pertinent to the new Gen IV reactor concepts. It is anticipated that current and planned future graphite irradiation experiments will provide the data needed to validate many of the currently accepted models, as well as providing the needed data for design confirmation.

  1. Direct synthesis of sp-bonded carbon chains on graphite surface by femtosecond laser irradiation

    SciTech Connect (OSTI)

    Hu, A.; Rybachuk, M.; Lu, Q.-B.; Duley, W. W.

    2007-09-24

    Microscopic phase transformation from graphite to sp-bonded carbon chains (carbyne) and nanodiamond has been induced by femtosecond laser pulses on graphite surface. UV/surface enhanced Raman scattering spectra and x-ray photoelectron spectra displayed the local synthesis of carbyne in the melt zone while nanocrystalline diamond and trans-polyacetylene chains form in the edge area of gentle ablation. These results evidence possible direct 'writing' of variable chemical bonded carbons by femtosecond laser pulses for carbon-based applications.

  2. 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.

    2013-06-12

    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.

  3. Oxidation state of cross-over manganese species on the graphite electrode

    Office of Scientific and Technical Information (OSTI)

    of lithium-ion cells (Journal Article) | SciTech Connect Oxidation state of cross-over manganese species on the graphite electrode of lithium-ion cells Citation Details In-Document Search Title: Oxidation state of cross-over manganese species on the graphite electrode of lithium-ion cells Authors: Gowda, Sanketh R. ; Gallagher, Kevin G. ; Croy, J. R. ; Bettge, Martin ; Thackeray, Michael ; Balasubramanian, Mahalingam Publication Date: 2014-01-01 OSTI Identifier: 1161339 DOE Contract Number:

  4. Putting the Spin on Graphite: Observing the Spins of Impurity Atoms Align |

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

    Stanford Synchrotron Radiation Lightsource Putting the Spin on Graphite: Observing 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 properties of a lightweight and robust material based on carbon that can also be produced and manipulated on the nanoscale fascinates scientists and engineers alike. Carbon-based materials can be made e.g. in the form of thin wires (1D), single

  5. Statistical Comparison of the Baseline Mechanical Properties of NBG-18 and PCEA Graphite

    SciTech Connect (OSTI)

    Mark C. Carroll; David T. Rohrbaugh

    2013-08-01

    High-purity graphite is the core structural material of choice in the Very High Temperature Reactor (VHTR), a graphite-moderated, helium-cooled design that is capable of producing process heat for power generation and for industrial process 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 by providing comprehensive data that captures the level of variation in measured values. In addition to providing a comprehensive comparison between these values in different nuclear grades, the program is also carefully tracking individual specimen source, position, and orientation information in order to provide comparisons and variations between different lots, different billets, and different positions from within a single billet. This report is a preliminary comparison between the two grades of graphite that were initially favored in the two main VHTR designs. NBG-18, a medium-grain pitch coke graphite from SGL formed via vibration molding, was the favored structural material in the pebble-bed configuration, while PCEA, a smaller grain, petroleum coke, extruded graphite from GrafTech was favored for the prismatic configuration. An analysis of the comparison between these two 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.

  6. GUM Analysis for SIMS Isotopic Ratios in BEP0 Graphite Qualification Samples, Round 2

    SciTech Connect (OSTI)

    Gerlach, David C.; Heasler, Patrick G.; Reid, Bruce D.

    2009-01-01

    This report describes GUM calculations for TIMS and SIMS isotopic ratio measurements of reactor graphite samples. These isotopic ratios are used to estimate reactor burn-up, and currently consist of various ratios of U, Pu, and Boron impurities in the graphite samples. The GUM calculation is a propagation of error methodology that assigns uncertainties (in the form of standard error and confidence bound) to the final estimates.

  7. The state of understanding of the lithium-ion-battery graphite solid

    Office of Scientific and Technical Information (OSTI)

    electrolyte interphase (SEI) and its relationship to formation cycling (Journal Article) | DOE PAGES The state of understanding of the lithium-ion-battery graphite solid electrolyte interphase (SEI) and its relationship to formation cycling « Prev Next » Title: The state of understanding of the lithium-ion-battery graphite solid electrolyte interphase (SEI) and its relationship to formation cycling Authors: An, Seong Jin ; Li, Jianlin ; Daniel, Claus ; Mohanty, Debasish ; Nagpure, Shrikant

  8. 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.

    1996-06-01

    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.

  9. The Dept. of Energy Artificial Retina project

    ScienceCinema (OSTI)

    None

    2010-09-01

    LLNL has assisted in the development of the first long-term retinal prosthesis - called an artificial retina - that can function for years inside the harsh biological environment of the eye. This work has been done in collaboration with four national laboratories (Argonne, Los Alamos, Oak Ridge and Sandia), four universities (the California Institute of Technology, the Doheny Eye Institute at USC, North Carolina State University and the University of California, Santa Cruz), an industrial partner (Second Sight® Medical Products Inc. of Sylmar, Calif.) and the U.S. Department of Energy. With this device, application-specific integrated circuits transform digital images from a camera into electric signals in the eye that the brain uses to create a visual image. In clinical trials, patients with vision loss were able to successfully identify objects, increase mobility and detect movement using the artificial retina.

  10. Brief History of Artificial Lighting Technology

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

    Artificial Lighting Technology - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  11. Artificial neural network cardiopulmonary modeling and diagnosis

    DOE Patents [OSTI]

    Kangas, L.J.; Keller, P.E.

    1997-10-28

    The present invention is a method of diagnosing a cardiopulmonary condition in an individual by comparing data from a progressive multi-stage test for the individual to a non-linear multi-variate model, preferably a recurrent artificial neural network having sensor fusion. The present invention relies on a cardiovascular model developed from physiological measurements of an individual. Any differences between the modeled parameters and the parameters of an individual at a given time are used for diagnosis. 12 figs.

  12. Artificial neural network cardiopulmonary modeling and diagnosis

    DOE Patents [OSTI]

    Kangas, Lars J.; Keller, Paul E.

    1997-01-01

    The present invention is a method of diagnosing a cardiopulmonary condition in an individual by comparing data from a progressive multi-stage test for the individual to a non-linear multi-variate model, preferably a recurrent artificial neural network having sensor fusion. The present invention relies on a cardiovascular model developed from physiological measurements of an individual. Any differences between the modeled parameters and the parameters of an individual at a given time are used for diagnosis.

  13. Bismuth Nanoparticle Decorating Graphite Felt as a High-Performance Electrode for an All-Vanadium Redox Flow Battery

    SciTech Connect (OSTI)

    Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chong M.; Sprenkle, Vincent L.; Wang, Wei

    2013-02-04

    The selection of electrode materials plays a great role in improving performances of all vanadium redox flow batteries (VRBs). Low-cost graphite felt (GF) as traditional electrode material has to be modified to address its issue of low electrocatalytic activity. In our paper, low-cost and highly conductive bismuth nanoparticles, as a powerful alternative electrocatalyst to noble metal, are proposed and synchronously electro-deposited onto the surface of GF while running flow cells employing the electrolytes containing suitable Bi3+. Although bismuth is proved to only take effect on the redox reaction of V(II)/V(III) and present at negative half-cell side, the whole cell electrochemical performances are significantly improved. In particular, the energy efficiency is increased by 11% owing to faster charge transfer as compared with one without Bi at high charge/discharge rate of 150 mA/cm2, which is prone to reduce stack size, thus dramatically reducing the cost. The excellent results show great promise of Bi nano-catalysts in the commercialization of VRBs in terms of product cost as well as electrochemical properties.

  14. 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

    2014-05-20

    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.

  15. Deep Eutectic Salt Formulations Suitable as Advanced Heat Transfer Fluids

    SciTech Connect (OSTI)

    Raade, Justin; Roark, Thomas; Vaughn, John; Bradshaw, Robert

    2013-07-22

    Concentrating solar power (CSP) facilities are comprised of many miles of fluid-filled pipes arranged in large grids with reflective mirrors used to capture radiation from the sun. Solar radiation heats the fluid which is used to produce steam necessary to power large electricity generation turbines. Currently, organic, oil-based fluid in the pipes has a maximum temperature threshold of 400 °C, allowing for the production of electricity at approximately 15 cents per kilowatt hour. The DOE hopes to foster the development of an advanced heat transfer fluid that can operate within higher temperature ranges. The new heat transfer fluid, when used with other advanced technologies, could significantly decrease solar electricity cost. Lower costs would make solar thermal electricity competitive with gas and coal and would offer a clean, renewable source of energy. Molten salts exhibit many desirable heat transfer qualities within the range of the project objectives. Halotechnics developed advanced heat transfer fluids (HTFs) for application in solar thermal power generation. This project focused on complex mixtures of inorganic salts that exhibited a high thermal stability, a low melting point, and other favorable characteristics. A high-throughput combinatorial research and development program was conducted in order to achieve the project objective. Over 19,000 candidate formulations were screened. The workflow developed to screen various chemical systems to discover salt formulations led to mixtures suitable for use as HTFs in both parabolic trough and heliostat CSP plants. Furthermore, salt mixtures which will not interfere with fertilizer based nitrates were discovered. In addition for use in CSP, the discovered salt mixtures can be applied to electricity storage, heat treatment of alloys and other industrial processes.

  16. On the Suitability of MPI as a PGAS Runtime

    SciTech Connect (OSTI)

    Daily, Jeffrey A.; Vishnu, Abhinav; Palmer, Bruce J.; van Dam, Hubertus JJ; Kerbyson, Darren J.

    2014-12-18

    Partitioned Global Address Space (PGAS) models are emerging as a popular alternative to MPI models for designing scalable applications. At the same time, MPI remains a ubiquitous communication subsystem due to its standardization, high performance, and availability on leading platforms. In this paper, we explore the suitability of using MPI as a scalable PGAS communication subsystem. We focus on the Remote Memory Access (RMA) communication in PGAS models which typically includes {\\em get, put,} and {\\em atomic memory operations}. We perform an in-depth exploration of design alternatives based on MPI. These alternatives include using a semantically-matching interface such as MPI-RMA, as well as not-so-intuitive interfaces such as MPI two-sided with a combination of multi-threading and dynamic process management. With an in-depth exploration of these alternatives and their shortcomings, we propose a novel design which is facilitated by the data-centric view in PGAS models. This design leverages a combination of highly tuned MPI two-sided semantics and an automatic, user-transparent split of MPI communicators to provide asynchronous progress. We implement the asynchronous progress ranks approach and other approaches within the Communication Runtime for Exascale which is a communication subsystem for Global Arrays. Our performance evaluation spans pure communication benchmarks, graph community detection and sparse matrix-vector multiplication kernels, and a computational chemistry application. The utility of our proposed PR-based approach is demonstrated by a 2.17x speed-up on 1008 processors over the other MPI-based designs.

  17. Identifying suitable "piercement" salt domes for nuclear waste storage sites

    SciTech Connect (OSTI)

    Kehle, R.

    1980-08-01

    Piercement salt domes of the northern interior salt basins of the Gulf of Mexico are being considered as permanent storage sites for both nuclear and chemically toxic wastes. The suitable domes are stable and inactive, having reached their final evolutionary configuration at least 30 million years ago. They are buried to depths far below the level to which erosion will penetrate during the prescribed storage period and are not subject to possible future reactivation. The salt cores of these domes are themselves impermeable, permitting neither the entry nor exit of ground water or other unwanted materials. In part, a stable dome may be recognized by its present geometric configuration, but conclusive proof depends on establishing its evolutionary state. The evolutionary state of a dome is obtained by reconstructing the growth history of the dome as revealed by the configuration of sedimentary strata in a large area (commonly 3,000 square miles or more) surrounding the dome. A high quality, multifold CDP reflection seismic profile across a candidate dome will provide much of the necessary information when integrated with available subsurface control. Additional seismic profiles may be required to confirm an apparent configuration of the surrounding strata and an interpreted evolutionary history. High frequency seismic data collected in the near vicinity of a dome are also needed as a supplement to the CDP data to permit accurate depiction of the configuration of shallow strata. Such data must be tied to shallow drill hole control to confirm the geologic age at which dome growth ceased. If it is determined that a dome reached a terminal configuration many millions of years ago, such a dome is incapable of reactivation and thus constitutes a stable storage site for nuclear wastes.

  18. Thermal Charging Study of Compressed Expanded Natural Graphite/Phase Change Material Composites

    SciTech Connect (OSTI)

    Mallow, Anne M; Abdelaziz, Omar; Graham, Samuel

    2016-01-01

    The thermal charging performance of phase change materials, specifically paraffin wax, combined with compressed expanded natural graphite foam is studied under constant heat flux and constant temperature conditions. By varying the heat flux between 0.39 W/cm2 and 1.55 W/cm2 or maintaining a boundary temperature of 60 C for four graphite foam bulk densities, the impact on the rate of thermal energy storage is discussed. Thermal charging experiments indicate that thermal conductivity of the composite is an insufficient metric to compare the influence of graphite foam on the rate of thermal energy storage of the PCM composite. By dividing the latent heat of the composite by the time to melt for various boundary conditions and graphite foam bulk densities, it is determined that bulk density selection is dependent on the applied boundary condition. A greater bulk density is advantageous for samples exposed to a constant temperature near the melting temperature as compared to constant heat flux conditions where a lower bulk density is adequate. Furthermore, the anisotropic nature of graphite foam bulk densities greater than 50 kg/m3 is shown to have an insignificant impact on the rate of thermal charging. These experimental results are used to validate a computational model for future use in the design of thermal batteries for waste heat recovery.

  19. Prediction and measurement of thermal transport across interfaces between isotropic solids and graphitic materials.

    SciTech Connect (OSTI)

    Hopkins, Patrick E.; Norris, Pamela M.; Smoyer, Justin L.; Duda, John C.

    2010-06-01

    Due to the high intrinsic thermal conductivity of carbon allotropes, there have been many attempts to incorporate such structures into existing thermal abatement technologies. In particular, carbon nanotubes (CNTs) and graphitic materials (i.e., graphite and graphene flakes or stacks) have garnered much interest due to the combination of both their thermal and mechanical properties. However, the introduction of these carbon-based nanostructures into thermal abatement technologies greatly increases the number of interfaces per unit length within the resulting composite systems. Consequently, thermal transport in these systems is governed as much by the interfaces between the constituent materials as it is by the materials themselves. This paper reports the behavior of phononic thermal transport across interfaces between isotropic thin films and graphite substrates. Elastic and inelastic diffusive transport models are formulated to aid in the prediction of conductance at a metal-graphite interface. The temperature dependence of the thermal conductance at Au-graphite interfaces is measured via transient thermoreflectance from 78 to 400 K. It is found that different substrate surface preparations prior to thin film deposition have a significant effect on the conductance of the interface between film and substrate.

  20. NanoSIMS, TEM, and XANES studies of a unique presolar supernova graphite grain

    SciTech Connect (OSTI)

    Groopman, Evan; Bernatowicz, Thomas; Zinner, Ernst; Nittler, Larry R.

    2014-07-20

    We report on isotopic and microstructural investigations of a unique presolar supernova (SN) graphite grain, referred to as G6, isolated from the Orgueil CI chondrite. G6 contains complex heterogeneities in its isotopic composition and in its microstructure. Nano-scale secondary ion mass spectrometer isotope images of ultramicrotome sections reveal heterogeneities in its C, N, and O isotopic compositions, including anomalous shell-like structures. Transmission electron microscope studies reveal a nanocrystalline core surrounded by a turbostratic graphite mantle, the first reported nanocrystalline core from a low-density SN graphite grain. Electron diffraction analysis shows that the nanocrystalline core consists of randomly oriented 2-4 nm graphene particles, similar to those in cores of high-density (HD) presolar graphite grains from asymptotic giant branch stars. G6's core also exhibits evidence for planar stacking of these graphene nano-sheets with a domain size up to 4.5 nm, which was unobserved in the nanocrystalline cores of HD graphite grains. We also report on X-ray absorption near-edge structure measurements of G6. The complex isotopic- and micro-structure of G6 provides evidence for mixing and/or granular transport in SN ejecta.

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

    SciTech Connect (OSTI)

    1999-05-01

    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.

  2. Evaluation of graphite/steam interactions for ITER (International Thermonuclear Experimental Reactor)

    SciTech Connect (OSTI)

    Smolik, G.R.; Merrill, B.J.; Piet, S.J.; Holland, D.F.

    1990-09-01

    In this report we present the results of an experimental/analytical study designed to determine the quantity of hydrogen generated during a coolant inleakage accident in ITER. This hydrogen could represent a potential explosive hazard, provided the proper conditions exist, causing machine damage and release of radioactive material. We have measured graphite/steam reaction rates for several graphites and carbon-based composites at temperatures between 1000 C and 1700 C. The effects of steam flow rate, and partial pressure were also examined. The measured reaction rates correlated well with two Arrhenius type relationships. We have used the relationships for GraphNOL N3M in a thermal model to determine that for ITER the quantity of hydrogen produced would range between 5 and 35 kg, depending upon how the graphite tiles are attached to the first wall. While 5 kg is not a significant concern, 35 kg presents an explosive hazard. 20 refs., 14 figs., 1 tab.

  3. Synthesis and characterization of nanocrystalline graphite from coconut shell with heating process

    SciTech Connect (OSTI)

    Wachid, Frischa M. E-mail: adhiyudhaperkasa@yahoo.com E-mail: nurulrosyidah92@gmail.com Perkasa, Adhi Y. E-mail: adhiyudhaperkasa@yahoo.com E-mail: nurulrosyidah92@gmail.com Prasetya, Fandi A. E-mail: adhiyudhaperkasa@yahoo.com E-mail: nurulrosyidah92@gmail.com Rosyidah, Nurul E-mail: adhiyudhaperkasa@yahoo.com E-mail: nurulrosyidah92@gmail.com Darminto E-mail: adhiyudhaperkasa@yahoo.com E-mail: nurulrosyidah92@gmail.com

    2014-02-24

    Graphite were synthesized and characterized by heating process of coconut shell with varying temperature (400, 800 and 1000°C) and holding time (3 and 5 hours). After heating process, the samples were characterized by X-ray diffraction (XRD) and analyzed by X'pert HighScore Plus Software, Scanning Electron Microcope-Energy Dispersive X-Ray (SEM-EDX) and Transmission Electron Microscope-Energy Dispersive X-Ray (TEM-EDX). Graphite and londsdaelite phase were analyzed by XRD. According to EDX analysis, the sample was heated in 1000°C got the highest content of carbon. The amorphous carbon and nanocrystalline graphite were observed by SEM-EDX and TEM-EDX.

  4. 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.; Xue, Sha; Crunkleton, Daniel W.; Shen, Yaogen; Wang, Sanwu

    2014-03-03

    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.

  5. Phonon mean free path of graphite along the c-axis

    SciTech Connect (OSTI)

    Wei, Zhiyong; Yang, Juekuan; Chen, Weiyu; Bi, Kedong; Chen, Yunfei, E-mail: yunfeichen@seu.edu.cn [Jiangsu Key Laboratory for Design and Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096 (China); Li, Deyu, E-mail: deyu.li@vanderbilt.edu [Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37235-1592 (United States)

    2014-02-24

    Phonon transport in the c-axis direction of graphite thin films has been studied using non-equilibrium molecular dynamics (MD) simulation. The simulation results show that the c-axis thermal conductivities for films of thickness ranging from 20 to 500 atomic layers are significantly lower than the bulk value. Based on the MD data, a method is developed to construct the c-axis thermal conductivity as an accumulation function of phonon mean free path (MFP), from which we show that phonons with MFPs from 2 to 2000?nm contribute ?80% of the graphite c-axis thermal conductivity at room temperature, and phonons with MFPs larger than 100?nm contribute over 40% to the c-axis thermal conductivity. These findings indicate that the commonly believed value of just a few nanometers from the simple kinetic theory drastically underestimates the c-axis phonon MFP of graphite.

  6. A facile approach to prepare graphene via solvothermal reduction of graphite oxide

    SciTech Connect (OSTI)

    Yuan, Bihe; Bao, Chenlu; Qian, Xiaodong; Wen, Panyue; Xing, Weiyi; Song, Lei; Hu, Yuan

    2014-07-01

    Highlights: • Graphene was prepared via a novel and facile solvothermal reduction method for graphite oxide. • Most of the oxygen functional groups of graphite oxide were removed. • The reduced graphene oxide obtained was featured with bilayer nanosheets. - Abstract: In this work, a facile reduction strategy is reported for the fabrication of graphene. Graphite oxide (GO) is reduced via a novel solvothermal reaction in a mixed solution of acetone and sodium hypochlorite (NaClO). The structure, surface chemistry, morphology and thermal stability of the as-prepared reduced graphene oxide (RGO) are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results indicate that most of the oxygenated groups in GO are effectively removed in this solvothermal reaction. The novel reduction method provides a simple, cost-effective and efficient strategy for the fabrication of graphene.

  7. 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)

    1995-01-01

    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.

  8. The semi-empirical tight-binding model for carbon allotropes between diamond and graphite

    SciTech Connect (OSTI)

    Lytovchenko, V.; Kurchak, A.; Strikha, M.

    2014-06-28

    The new carbon allotropes between diamond and graphite have come under intensive examination during the last decade due to their numerous technical applications. The modification of energy gap in thin films of these allotropes was studied experimentally using optical methods. The proposed simple model of carbon clusters with variable lengths of chemical bonds allows us to imitate the transfer from diamond and diamond-like to graphite-like structures, as well as the corresponding modification of hybridization sp{sup 3}/sp{sup 2} for diamond-like and sp{sub z} for graphite-like phases. This enables us to estimate various allotropes parameters, like the gap E{sub g}, energies of valence E{sub v}, and conduction E{sub c} band edges, and the value of electronic affinity, i.e., optical work function X, which are all of practical importance. The obtained estimations correspond to the experimental data.

  9. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    DOE Patents [OSTI]

    Bond, Tiziana C; Miles, Robin; Davidson, James; Liu, Gang Logan

    2015-11-03

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  10. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    DOE Patents [OSTI]

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2015-07-14

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  11. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    DOE Patents [OSTI]

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2014-07-22

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  12. Artificial Retina Project: Electromagnetic and Thermal Effects

    SciTech Connect (OSTI)

    Lazzi, Gianluca

    2014-08-29

    This award supported the investigation on electromagnetic and thermal effects associated with the artificial retina, designed in collaboration with national laboratories, universities, and private companies. Our work over the two years of support under this award has focused mainly on 1) Design of new telemetry coils for optimal power and data transfer between the implant and the external device while achieving a significant size reduction with respect to currently used coils; 2) feasibility study of the virtual electrode configuration 3) study the effect of pulse shape and duration on the stimulation efficacy.

  13. Raman spectroscopy of graphite in high magnetic fields: Electron-phonon coupling and magnetophonon resonance

    SciTech Connect (OSTI)

    Kim, Younghee; Smirnov, Dmitry; Kalugin, Nikolai G.; Lombardo, Antonio; Ferrari, Andrea C.

    2013-12-04

    The magneto-Raman measurements of graphite were performed in a back-scattering Faraday geometry at temperature 10 K in magnetic fields up to 45 T. The experimental data reveal the rich structure of Raman-active excitations dominated by K-point massive electrons. At high magnetic fields the graphite E{sub 2g} Raman line shows complex multi- component behavior interpreted as magnetophonon resonance coupled electron-phonon modes at graphite’s K-point. Also we found the clear signature of the fundamental, strongly dumped, n=0 magnetophonon resonance associated with H point massless holes.

  14. First approximations of phonon thermal transport at solid-graphite interfaces.

    SciTech Connect (OSTI)

    Hopkins, Patrick E.; Norris, Pamela M.; Beechem, Thomas Edwin, Iii; Smoyer, Justin L.; Duda, John C.

    2010-04-01

    This model predicts thermal boundary conductance at interfaces where one material comprising the junction is characterized by high elastic anisotropy (i.e, graphite). The thermal properties of graphite are determined through a simplified vibrational model, where the bulk structure is treated as an linear assembly of two-dimensional systems. This model is validated at temperatures above cryogenic through comparison to experimentally determined values of specific heat. Elastic processes are accounted for through traditional diffuse transport theory. Inelastic contributions due to multi-phonon processes are also addressed and quantified.

  15. Density Functional Study of Au-n110(n = 3-5) Clusters on Relaxed Graphite

    Office of Scientific and Technical Information (OSTI)

    Surfaces (Journal Article) | SciTech Connect Density Functional Study of Au-n110(n = 3-5) Clusters on Relaxed Graphite Surfaces Citation Details In-Document Search Title: Density Functional Study of Au-n110(n = 3-5) Clusters on Relaxed Graphite Surfaces No abstract prepared. Authors: Wang, Guan M. ; BelBruno, Joseph J. ; Kenny, Steven D. ; Smith, Roger Publication Date: 2005-02-10 OSTI Identifier: 15011649 DOE Contract Number: AC05-76RL01830 Resource Type: Journal Article Resource Relation:

  16. Analysis of a graphite foam-NaCl latent heat storage system for

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

    supercritical CO2 power cycles for concentrated solar power | Argonne National Laboratory Analysis of a graphite foam-NaCl latent heat storage system for supercritical CO2 power cycles for concentrated solar power Title Analysis of a graphite foam-NaCl latent heat storage system for supercritical CO2 power cycles for concentrated solar power Publication Type Journal Article Year of Publication 2015 Authors Singh, D, Zhao, W, Yu, W, France, DM, Kim, T Journal Solar Energy Volume 118 Start

  17. Stories of Discovery & Innovation: A Step Toward Artificial Photosynthesis

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

    | U.S. DOE Office of Science (SC) A Step Toward Artificial Photosynthesis Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights News & Events EFRC News EFRC Events DOE Announcements Publications History Contact BES Home 01.06.12 Stories of Discovery & Innovation: A Step Toward Artificial Photosynthesis Print Text Size: A A A Subscribe FeedbackShare Page EFRC researchers construct an artificial version of a bacterium's light-absorbing

  18. Science On Tap - From Trinity to Artificial Joints

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

    Science On Tap - From Trinity to Artificial Joints Science On Tap - From Trinity to Artificial Joints WHEN: Jul 16, 2015 5:30 PM - 7:00 PM WHERE: UnQuarked Wine Room 145 Central Park Square, Los Alamos, New Mexico 87544, USA SPEAKER: Nathaniel Morgan, Los Alamos National Laboratory CONTACT: Jessica Privette 505 667-0375 CATEGORY: Bradbury INTERNAL: Calendar Login Science on Tap series Event Description From Trinity to artificial joints: How computational mathematics has transformed our world.

  19. DNA-Directed Artificial Light-Harvesting Antenna

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

    DNA-Directed Artificial Light-Harvesting Antenna Authors: Dutta, P. K., Varghese, R., Nangreave, J., Lin, S., Yan, H., and Liu, Y. Title: DNA-Directed Artificial Light-Harvesting Antenna Source: Journal of the American Chemical Society Year: 2011 Volume: 133 Pages: 11985-11993 ABSTRACT: Designing and constructing multichromophoric, artificial light-harvesting antennas with controlled interchromophore distances, orientations, and defined donor?acceptor ratios to facilitate efficient

  20. MHK Technologies/Electroactive Polymer Artificial Muscle EPAM...

    Open Energy Info (EERE)

    that it uses SRI s Electroactive Polymer Artificial Muscle EPAM technology a rubbery material that can generate electricity by simply being stretched and allowed to return to its...

  1. Artificial Photosynthesis I - Design Principles for Light Harvesting

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

    I Artificial Photosynthesis I - Design Principles for Light Harvesting FlemingSmall.png Key Challenges: Researchers measure a two-dimensional (2D) Fourier transform electronic...

  2. Scientist's Quest For Artificial Muscle Aided by PPPL | Princeton...

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

    in the development of electro-responsive "smart materials" - electrically-driven polymers that are strong and durable enough to act as artificial muscles in prosthetic devices...

  3. Science On Tap - From Trinity to Artificial Joints

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

    artificial human joints, and biological implants, using MRI scanning software, radiation therapy and even creating cartoons is all done using computational mathematics. The world...

  4. 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)

    2013-07-01

    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)

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

    SciTech Connect (OSTI)

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

    2014-01-01

    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.

  6. The Next Generation Nuclear Plant Graphite Creep Experiment Irradiation in the Advanced Test Reactor

    SciTech Connect (OSTI)

    Blaine Grover

    2010-10-01

    The United States Department of Energys 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 United States Department of Energys lead laboratory for nuclear energy development. The ATR is one of the worlds 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, 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 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 stacks will have differing 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 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 first experiment was inserted in the ATR in August 2009 and started its irradiation in September 2009. It is anticipated to complete its irradiation in early calendar 2011. This paper will discuss the design of the experiment including the test train and the temperature and compressive load monitoring, control, and the irradiation experience to date.

  7. Enhancement of oxidation resistance of graphite foams by polymer derived-silicon carbide coating for concentrated solar power applications

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

    Kim, T.; Singh, D.; Singh, M.

    2015-05-01

    Graphite foam with extremely high thermal conductivity has been investigated to enhance heat transfer of latent heat thermal energy storage (LHTES) systems. However, the use of graphite foam for elevated temperature applications (>600 °C) is limited due to poor oxidation resistance of graphite. In the present study, oxidation resistance of graphite foam coated with silicon carbide (SiC) was investigated. A pre-ceramic polymer derived coating (PDC) method was used to form a SiC coating on the graphite foams. Post coating deposition, the samples were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The oxidation resistance of PDC-SiC coating was quantifiedmore » by measuring the weight of the samples at several measuring points. The experiments were conducted under static argon atmosphere in a furnace. After the experiments, oxidation rates (%/hour) were calculated to predict the lifetime of the graphite foams. The experimental results showed that the PDC-SiC coating could prevent the oxidation of graphite foam under static argon atmosphere up to 900 °C.« less

  8. Enhancement of oxidation resistance of graphite foams by polymer derived-silicon carbide coating for concentrated solar power applications

    SciTech Connect (OSTI)

    Kim, T.; Singh, D.; Singh, M.

    2015-05-01

    Graphite foam with extremely high thermal conductivity has been investigated to enhance heat transfer of latent heat thermal energy storage (LHTES) systems. However, the use of graphite foam for elevated temperature applications (>600 °C) is limited due to poor oxidation resistance of graphite. In the present study, oxidation resistance of graphite foam coated with silicon carbide (SiC) was investigated. A pre-ceramic polymer derived coating (PDC) method was used to form a SiC coating on the graphite foams. Post coating deposition, the samples were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The oxidation resistance of PDC-SiC coating was quantified by measuring the weight of the samples at several measuring points. The experiments were conducted under static argon atmosphere in a furnace. After the experiments, oxidation rates (%/hour) were calculated to predict the lifetime of the graphite foams. The experimental results showed that the PDC-SiC coating could prevent the oxidation of graphite foam under static argon atmosphere up to 900 °C.

  9. Influence of Fe-doped Graphite Electrode Characteristics on Ar-H2 Carbon Arc Plasma and SWCNT Formation

    SciTech Connect (OSTI)

    Huczko, A.; Lange, H.; Bystrzejewski, M.; Ando, Y.; Zhao, X.; Inoue, S.

    2005-09-27

    Two Fe-doped (ca. 1 at.%) homogeneous graphite electrodes (different graphite microcrystals, degree of graphitization and, thereby, electrical conductivities) electrodes were used in the process of production of single-walled carbon nanotubes in Ar-H2 arc plasma under pressure 26 kPa. The C2 content (namely carbon vapor pressure) and temperature distributions in the arc plasma were determined using optical emission spectroscopy. The mechanism of CNT formation based on carbon dimers as the building blocks seems to be at least questionable.

  10. Artificial intelligence technologies applied to terrain analysis

    SciTech Connect (OSTI)

    Wright, J.C. ); Powell, D.R. )

    1990-01-01

    The US Army Training and Doctrine Command is currently developing, in cooperation with Los Alamos National Laboratory, a Corps level combat simulation to support military analytical studies. This model emphasizes high resolution modeling of the command and control processes, with particular attention to architectural considerations that enable extension of the model. A planned future extension is the inclusion of an computer based planning capability for command echelons that can be dynamical invoked during the execution of then model. Command and control is the process through which the activities of military forces are directed, coordinated, and controlled to achieve the stated mission. To perform command and control the commander must understand the mission, perform terrain analysis, understand his own situation and capabilities as well as the enemy situation and his probable actions. To support computer based planning, data structures must be available to support the computer's ability to understand'' the mission, terrain, own capabilities, and enemy situation. The availability of digitized terrain makes it feasible to apply artificial intelligence technologies to emulate the terrain analysis process, producing data structures for uses in planning. The work derived thus for to support the understanding of terrain is the topic of this paper. 13 refs., 5 figs., 6 tabs.

  11. Relationships between strength, electrical conductivity, and density for oxidized PGX graphite

    SciTech Connect (OSTI)

    Morgan, W.C.; Prince, J.M.

    1983-07-01

    The core of a High Temperature Gas-Cooled Reactor (HTGR) rests on massive graphite core support blocks; which, in turn, are supported by core support posts. PGX graphite was used for the core support blocks of the Fort St. Vrain HTGR (the only operating HTGR); and, evidently, is the leading candidate material for use in advanced HTGRs. Therefore, PGX was chosen for the initial tests on the use of eddy current techniques to monitor strength changes as a result of oxidation. The results of these initial tests showed that both compressive strength and electrical conductivity correlated very well with density. However, only a single log of PGX was used for the initial tests; therefore, it was necessary to determine if the correlations could be extended to other logs of PGX.

  12. Evidence of transition-metal accumulation on aged graphite anodes by SIMS.

    SciTech Connect (OSTI)

    Abraham, D. P.; Spila, T.; Furczon, M. M.; Sammann, E.; Chemical Sciences and Engineering Division; Univ. of Illinois

    2008-01-01

    In cells containing Li{sub 1.05}(Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}){sub 0.95}O{sub 2}-based positive and graphite-based negative electrodes, a significant portion of cell impedance rise on aging is known to be from the negative electrode. One possible reason for this impedance rise is the dissolution of transition-metal elements from the oxide electrode that accumulate and create a high-impedance layer at the negative electrode-electrolyte interface. This article details dynamic secondary ion mass spectrometry (SIMS) measurements, which provide a relative comparison of Mn, Co, and Ni contents on fresh, formed, and aged graphite electrodes. The data clearly indicate that these transition-metal elements accumulate at the electrode surface and diffuse into the electrode during cell aging.

  13. Research into Oil-based Colloidal-Graphite Lubricants for Forging of Al-based Alloys

    SciTech Connect (OSTI)

    Petrov, A.; Petrov, P.; Petrov, M.

    2011-05-04

    The presented paper describes the topical problem in metal forging production. It deals with the choice of an optimal lubricant for forging of Al-based alloys. Within the scope of the paper, the properties of several oil-based colloidal-graphite lubricants were investigated. The physicochemical and technological properties of these lubricants are presented. It was found that physicochemical properties of lubricant compositions have an influence on friction coefficient value and quality of forgings.The ring compression method was used to estimate the friction coefficient value. Hydraulic press was used for the test. The comparative analysis of the investigated lubricants was carried out. The forging quality was estimated on the basis of production test. The practical recommendations were given to choose an optimal oil-based colloidal-graphite lubricant for isothermal forging of Al-based alloy.

  14. Atomic friction at exposed and buried graphite step edges: Experiments and simulations

    SciTech Connect (OSTI)

    Ye, Zhijiang; Martini, Ashlie

    2015-06-08

    The surfaces of layered materials such as graphite exhibit step edges that affect friction. Step edges can be exposed, where the step occurs at the outmost layer, or buried, where the step is underneath another layer of material. Here, we study friction at exposed and buried step edges on graphite using an atomic force microscope (AFM) and complementary molecular dynamics simulations of the AFM tip apex. Exposed and buried steps exhibit distinct friction behavior, and the friction on either step is affected by the direction of sliding, i.e., moving up or down the step, and the bluntness of the tip. These trends are analyzing in terms of the trajectory of the AFM tip as it moves over the step, which is a convolution of the topography of the surface and the tip shape.

  15. Continious production of exfoliated graphite composite compositions and flow field plates

    DOE Patents [OSTI]

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

    2010-07-20

    A process of continuously producing a more isotropic, electrically conductive composite composition is provided. The process comprises: (a) continuously supplying a compressible mixture comprising exfoliated graphite worms and a binder or matrix material, wherein the binder or matrix material is in an amount of between 3% and 60% by weight based on the total weight of the mixture; (b) continuously compressing the compressible mixture at a pressure within the range of from about 5 psi or 0.035 MPa to about 50,000 psi or 350 MPa in at least a first direction into a cohered graphite composite compact; and (c) continuously compressing the composite compact in a second direction, different from the first direction, to form the composite composition in a sheet or plate form. The process leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  16. 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)

    2014-11-01

    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.

  17. Abundances of presolar graphite and SiC from supernovae and AGB stars in the Murchison meteorite

    SciTech Connect (OSTI)

    Amari, Sachiko; Zinner, Ernst; Gallino, Roberto

    2014-05-02

    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.

  18. SWEPP PAN assay system uncertainty analysis: Passive mode measurements of graphite waste

    SciTech Connect (OSTI)

    Blackwood, L.G.; Harker, Y.D.; Meachum, T.R.; Yoon, Woo Y.

    1997-07-01

    The Idaho National Engineering and Environmental Laboratory is being used as a temporary storage facility for transuranic waste generated by the U.S. Nuclear Weapons program at the Rocky Flats Plant (RFP) in Golden, Colorado. Currently, there is a large effort in progress to prepare to ship this waste to the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. In order to meet the TRU Waste Characterization Quality Assurance Program Plan nondestructive assay compliance requirements and quality assurance objectives, it is necessary to determine the total uncertainty of the radioassay results produced by the Stored Waste Examination Pilot Plant (SWEPP) Passive Active Neutron (PAN) radioassay system. To this end a modified statistical sampling and verification approach has been developed to determine the total uncertainty of a PAN measurement. In this approach the total performance of the PAN nondestructive assay system is simulated using computer models of the assay system and the resultant output is compared with the known input to assess the total uncertainty. This paper is one of a series of reports quantifying the results of the uncertainty analysis of the PAN system measurements for specific waste types and measurement modes. In particular this report covers passive mode measurements of weapons grade plutonium-contaminated graphite molds contained in 208 liter drums (waste code 300). The validity of the simulation approach is verified by comparing simulated output against results from measurements using known plutonium sources and a surrogate graphite waste form drum. For actual graphite waste form conditions, a set of 50 cases covering a statistical sampling of the conditions exhibited in graphite wastes was compiled using a Latin hypercube statistical sampling approach.

  19. Preliminary investigations into the microcracking of PMR-15/graphite composites. I. Effect of cure temperature

    SciTech Connect (OSTI)

    Wilson, D.; Wells, J.K.; Hay, J.N.; Lind, D.; Owens, G.A.

    1987-06-01

    The thermosetting polyimide, PMR-15, is the leading matrix resin for high temperature polymer composites. The effect of cure temperature has been evaluated. PMR-15/graphite laminates have been prepared by curing at a range of temperatures. Mechanical and microcracking properties and thermooxidative stability of the laminates have been determined. Results indicated that low temperature cure (280-290 C) of PMR-15 is possible to produce composites of acceptable mechanical properties that show a significantly reduced tendency to microcrack. 19 references.

  20. Designing artificial metal binding peptides | Center for Bio...

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

    artificial metal binding peptides 24 Oct 2012 Dong Wang is a graduate student in the Department of Chemistry and Biochemistry at Arizona State University. He is working in the lab...

  1. Magnetic charge crystals imaged in artificial spin ice

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

    image of emergent domains of ordered magnetic charges in honeycomb artificial spin ice. The black and white dots in the image are the north and south magnetic poles of the...

  2. Polymer surfaces graphitization by low-energy He{sup +} ions irradiation

    SciTech Connect (OSTI)

    Geworski, A.; Lazareva, I.; Gieb, K.; Koval, Y.; Mller, P. [Department of Physics, Universitt Erlangen-Nrnberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany)

    2014-08-14

    The electrical and optical properties of surfaces of polyimide and AZ5214e graphitized by low-energy (1?keV) He{sup +} irradiation at different polymer temperatures were investigated. The conductivity of the graphitized layers can be controlled with the irradiation temperature within a broad range and can reach values up to ?1000?S/cm. We show that the electrical transport in low-conducting samples is governed by thermally activated hopping, while the samples with a high conductivity show a typical semimetallic behavior. The transition from thermally activated to semimetallic conductance governed by the irradiation temperature could also be observed in optical measurements. The semimetallic samples show an unusually high for graphitic materials carrier concentration, which results in a high extinction coefficient in the visible light range. By analyzing the temperature dependence of the conductance of the semimetallic samples, we conclude that the scattering of charge carriers is dominated by Coulomb interactions and can be described by a weak localization model. The transition from a three to two dimensional transport mechanism at low temperatures consistently explains the change in the temperature dependence of the conductance by cooling, observed in experiments.

  3. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect (OSTI)

    Duffy, Stephen

    2013-09-09

    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.

  4. 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

    2014-06-01

    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, ΔQ/ΔV 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.

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

    SciTech Connect (OSTI)

    S. Blaine Grover

    2014-05-01

    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.

  6. Towards Artificial Photosynthesis and Alternative Energy | Center for

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

    Bio-Inspired Solar Fuel Production Center News Research Highlights Center Research News Media about Center Center Video Library Bisfuel Picture Gallery Towards Artificial Photosynthesis and Alternative Energy 9 Apr 2013 On Tuesday April 9th, 2013, Professor Devens Gust, Director of the Center for Bio-Inspired Solar Fuel Production, presented a lecture for high school students titled "Towards Artificial Photosynthesis and Alternative Energy". The lecture highlights modern approaches

  7. Light Trapping, Absorption and Solar Energy Harvesting by Artificial

    Office of Scientific and Technical Information (OSTI)

    Materials (Technical Report) | SciTech Connect Technical Report: Light Trapping, Absorption and Solar Energy Harvesting by Artificial Materials Citation Details In-Document Search Title: Light Trapping, Absorption and Solar Energy Harvesting by Artificial Materials We provide designs of thin-film solar cells utilizing optimized photonic-crystal light-trapping and numerical simulations of their solar-to-electrical power conversion efficiencies. Authors: John, Sajeev [1] + Show Author

  8. Real and effective thermal equilibrium in artificial square spin ices

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Real and effective thermal equilibrium in artificial square spin ices Citation Details In-Document Search Title: Real and effective thermal equilibrium in artificial square spin ices Authors: Morgan, Jason P. ; Akerman, Johanna ; Stein, Aaron ; Phatak, Charudatta ; Evans, R. M. L. ; Langridge, Sean ; Marrows, Christopher H. Publication Date: 2013-01-09 OSTI Identifier: 1101866 Type: Publisher's Accepted Manuscript Journal Name: Physical Review B Additional

  9. Artificial Photosynthetic Reaction Center with a Coumarin-Based Antenna

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

    System Artificial Photosynthetic Reaction Center with a Coumarin-Based Antenna System Authors: Garg, V., Kodis, G., Liddell, P., Terazono, Y., Moore, T., Moore, A., and Gust, D. Title: Artificial Photosynthetic Reaction Center with a Coumarin-Based Antenna System Source: Journal of Physical Chemistry B Year: 2013 Volume: 117 Pages: 11299-11308 ABSTRACT: In photosynthesis, sunlight is absorbed mainly by antenna chromophores that transfer singlet excitation energy to reaction centers for

  10. Artificial films mimic myelin sheath in new research

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

    September » Artificial films mimic myelin sheath in new research Artificial films mimic myelin sheath in new research This platform provides a model for robust implementation of phospholipid multilayers and a means toward future applications of functional phospholipid supramolecular assemblies in device integration. September 11, 2013 Schematic of robust hybrid model membrane Schematic of robust hybrid model membrane The journal ACS Nano published the research team's findings, and this is the

  11. De novo design of functional proteins: Toward artificial hydrogenases

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

    De novo design of functional proteins: Toward artificial hydrogenases Authors: Faiella, M., Roy, A., Sommer, D., Ghirlanda, G. Title: De novo design of functional proteins: Toward artificial hydrogenases Source: Biopolymers Year: 2013 Volume: 100 Pages: 558 - 571 ABSTRACT: Over the last 25 years, de novo design has proven to be a valid approach to generate novel, well-folded proteins, and most recently, functional proteins. In response to societal needs, this approach is been used increasingly

  12. Artificial films mimic myelin sheath in new research

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

    Artificial films mimic myelin sheath in new research Artificial films mimic myelin sheath in new research This platform provides a model for robust implementation of phospholipid multilayers and a means toward future applications of functional phospholipid supramolecular assemblies in device integration. September 11, 2013 Schematic of robust hybrid model membrane Schematic of robust hybrid model membrane The journal ACS Nano published the research team's findings, and this is the first report

  13. Assessment of Small Modular Reactor Suitability for Use On or Near Air

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

    Force Space Command Installations SAND 2016-2600 | Department of Energy Small Modular Reactor Suitability for Use On or Near Air Force Space Command Installations SAND 2016-2600 Assessment of Small Modular Reactor Suitability for Use On or Near Air Force Space Command Installations SAND 2016-2600 This report assesses the suitability of using US-developed light water SMR technology to provide energy for Schriever Air Force Base, CO and Clear Air Force Station, AK, as well as broader SMR

  14. Rare-earth tantalates and niobates suitable for use as nanophosphors

    DOE Patents [OSTI]

    Nyman, May D; Rohwer, Lauren E.S& gt

    2013-11-19

    A family of rare-earth Group 5 oxides, where the Group 5 oxide is a niobate or tantalate. The rare-earth Group 5 oxides can be doped with suitable emitter ions to form nanophosphors.

  15. Synthesis of SiO{sub 2}/?-SiC/graphite hybrid composite by low temperature hot filament chemical vapor deposition

    SciTech Connect (OSTI)

    Zhang, Zhikun; Bi, Kaifeng; Liu, Yanhong; Qin, Fuwen; Liu, Hongzhu; Bian, Jiming; Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200050 ; Zhang, Dong; Miao, Lihua; Department of Computer and Mathematical Basic Teaching, Shenyang Medical College, Shenyan 110034

    2013-11-18

    ?-SiC thin films were synthesized directly on graphite by hot filament chemical vapor deposition at low temperature. SiH{sub 4} diluted in hydrogen was employed as the silicon source, while graphite was functioned as both substrate and carbon source for the as-grown ?-SiC films. X-ray diffraction and Fourier transform infrared analysis indicate that SiO{sub 2}/?-SiC/graphite hybrid composite was formed after post annealing treatment, and its crystalline quality can be remarkably improved under optimized annealing conditions. The possible growth mechanism was proposed based on in situ etching of graphite by reactive hydrogen radicals at the atomic level.

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

    SciTech Connect (OSTI)

    Von L. Richards

    2012-09-19

    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.

  17. Scale-Up Maturation Plan for Digestion of Graphite Fuel Pebbles

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

    Scale-Up Maturation Plan for Digestion of Graphite Fuel Pebbles Official Use Only Pre-decisional Draft R. A. Pierce K. M. Fox June 2014 SRNL-RP-2014-00464, Revision 0 SRNL-RP-2014-00464 Revision 0 -- Official Use Only -- ii DISCLAIMER This work was prepared under an agreement with and funded by the U.S. Government. Neither the U.S. Government or its employees, nor any of its contractors, subcontractors or their employees, makes any express or implied: 1. warranty or assumes any legal liability

  18. Possible Diamond-Like Nanoscale Structures Induced by Slow Highly-Charged Ions on Graphite (HOPG)

    SciTech Connect (OSTI)

    Sideras-Haddad, E.; Schenkel, T.; Shrivastava, S.; Makgato, T.; Batra, A.; Weis, C. D.; Persaud, A.; Erasmus, R.; Mwakikunga, B.

    2009-01-06

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosizeareas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  19. Conceptual design of a high throughput electrorefining of a uranium by using graphite cathode

    SciTech Connect (OSTI)

    Lee, J.H.; Kang, Y.H.; Hwang, S.C.; Park, S.B.; Shim, J.B.; Lee, H.S.; Kim, E.H.; Park, S.W.

    2007-07-01

    Conceptual designing of a high throughput electro-refiner was performed by using basic experimental data and a commercial computational fluid dynamic code, CFX. An electro-refiner concept equipped with a graphite cathode bundle was designed to recover a high purity uranium product continuously without a noble metal contamination. The performance of the process for a decontamination of a noble metal in a uranium product was evaluated as a function of the process parameters such as the rotation speeds of the stirrer and the anode basket. (authors)

  20. Transition metals on the (0001) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology

    SciTech Connect (OSTI)

    Appy, David [Ames Laboratory; Lei, Huaping [Ames Laboratory; Wang, Cai-Zhuang [Ames Laboratory; Tringides, Michael C [Ames Laboratory; Liu, Da-Jiang [Ames Laboratory; Evans, James W [Ames Laboratory; Thiel, Patricia A [Ames Laboratory

    2014-08-01

    In this article, we review basic information about the interaction of transition metal atoms with the (0 0 0 1) surface of graphite, especially fundamental phenomena related to growth. Those phenomena involve adatom-surface bonding, diffusion, morphology of metal clusters, interactions with steps and sputter-induced defects, condensation, and desorption. General traits emerge which have not been summarized previously. Some of these features are rather surprising when compared with metal-on-metal adsorption and growth. Opportunities for future work are pointed out.

  1. Experimental Observations and Numerical Prediction of Induction Heating in a Graphite Test Article

    SciTech Connect (OSTI)

    Jankowski, Todd A [Los Alamos National Laboratory; Johnson, Debra P [Los Alamos National Laboratory; Jurney, James D [Los Alamos National Laboratory; Freer, Jerry E [Los Alamos National Laboratory; Dougherty, Lisa M [Los Alamos National Laboratory; Stout, Stephen A [Los Alamos National Laboratory

    2009-01-01

    The induction heating coils used in the plutonium casting furnaces at the Los Alamos National Laboratory are studied here. A cylindrical graphite test article has been built, instrumented with thermocouples, and heated in the induction coil that is normally used to preheat the molds during casting operations. Preliminary results of experiments aimed at understanding the induction heating process in the mold portion of the furnaces are reported. The experiments have been modeled in COMSOL Multiphysics and the numerical and experimental results are compared to one another. These comparisons provide insight into the heating process and provide a benchmark for COMSOL calculations of induction heating in the mold portion of the plutonium casting furnaces.

  2. Catalytic gasification of graphite or carbon. Quarterly report, January 1, 1986-March 31, 1986

    SciTech Connect (OSTI)

    Heinemann, H.

    1986-03-01

    Steam gasification of five chars has been carried out in the presence of a mixture of potassium and nickel oxides as catalyst. The steady state rate of hydrogen production after 60 minutes at 620/sup 0/C is highest for a N. Dakota Husky lignite and is twice as high as the next char, Western Kentucky. The order is N. Dakota > W. Kentucky > Illinois number 6, low temp. > number 6, high temp. > Montana. All chars gasified at a rate at least one order of magnitude greater than graphite.

  3. Determining whether metals nucleate homogeneously on graphite: A case study with copper

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

    Appy, David; Lei, Huaping; Han, Yong; Wang, Cai -Zhuang; Tringides, Michael C.; Shao, Dahai; Kwolek, Emma J.; Evans, J. W.; Thiel, P. A.

    2014-11-05

    In this study, we observe that Cu clusters grow on surface terraces of graphite as a result of physical vapor deposition in ultrahigh vacuum. We show that the observation is incompatible with a variety of models incorporating homogeneous nucleation and calculations of atomic-scale energetics. An alternative explanation, ion-mediated heterogeneous nucleation, is proposed and validated, both with theory and experiment. This serves as a case study in identifying when and whether the simple, common observation of metal clusters on carbon-rich surfaces can be interpreted in terms of homogeneous nucleation. We describe a general approach for making system-specific and laboratory-specific predictions.

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

    DOE Patents [OSTI]

    Guadalupe, Ana R.; Guo, Yizhu

    2001-05-15

    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.

  5. Lighting system combining daylight concentrators and an artificial source

    DOE Patents [OSTI]

    Bornstein, Jonathan G.; Friedman, Peter S.

    1985-01-01

    A combined lighting system for a building interior includes a stack of luminescent solar concentrators (LSC), an optical conduit made of preferably optical fibers for transmitting daylight from the LSC stack, a collimating lens set at an angle, a fixture for receiving the daylight at one end and for distributing the daylight as illumination inside the building, an artificial light source at the other end of the fixture for directing artifical light into the fixture for distribution as illumination inside the building, an automatic dimmer/brightener for the artificial light source, and a daylight sensor positioned near to the LSC stack for controlling the automatic dimmer/brightener in response to the daylight sensed. The system also has a reflector positioned behind the artificial light source and a fan for exhausting heated air out of the fixture during summer and for forcing heated air into the fixture for passage into the building interior during winter.

  6. Selection of a suitable reactor type for water desalination and power generation in Saudi Arabia

    SciTech Connect (OSTI)

    Hussein, F.M.

    1988-03-01

    Selection of a reactor type suitable for water desalination and power generation is a complex process that involves the evaluation of many criteria and requires the professional judgment of many experts in different fields. A reactor type that is suitable for one country might not be suitable for another. This is especially true in the case of Saudi Arabia because of its strategic location, the nature of its land and people, and its moderate technological situation. A detailed study using a computer code based on Saaty's mathematical pairwise comparison technique and developed in a previous study was carried out to find the most suitable reactor for water desalination and power generation in Saudi Arabia from among five potential types: boiling water reactors (BWRs), pressurized water reactors, CANDU heavy water reactors (HWRs), steam-generating heavy water reactors (SGHWRs), and high-temperature gas-cooled reactors. It was concluded that the CANDU HWR is the most suitable type for this purpose followed first by the BWR, then the SGHWR.

  7. Electroelastic fields in artificially created vortex cores in epitaxial

    Office of Scientific and Technical Information (OSTI)

    BiFeO3 thin films (Journal Article) | SciTech Connect Electroelastic fields in artificially created vortex cores in epitaxial BiFeO3 thin films Citation Details In-Document Search This content will become publicly available on August 4, 2016 Title: Electroelastic fields in artificially created vortex cores in epitaxial BiFeO3 thin films Authors: Winchester, B. [1] ; Balke, N. [2] ; Cheng, X. X. [1] ; Morozovska, A. N. [3] ; Kalinin, S. [2] Search SciTech Connect for author "Kalinin,

  8. Computers for artificial intelligence a technology assessment and forecast

    SciTech Connect (OSTI)

    Miller, R.K.

    1986-01-01

    This study reviews the development and current state-of-the-art in computers for artificial intelligence, including LISP machines, AI workstations, professional and engineering workstations, minicomputers, mainframes, and supercomputers. Major computer systems for AI applications are reviewed. The use of personal computers for expert system development is discussed, and AI software for the IBM PC, Texas Instrument Professional Computer, and Apple MacIntosh is presented. Current research aimed at developing a new computer for artificial intelligence is described, and future technological developments are discussed.

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

    SciTech Connect (OSTI)

    Blaine Grover

    2012-10-01

    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.

  10. Neutron irradiation induced microstructural changes in NBG-18 and IG-110 nuclear graphites

    SciTech Connect (OSTI)

    Karthik, Chinnathambi; Kane, Joshua; Butt, Darryl P.; Windes, William E.; Ubic, Rick

    2015-05-01

    This paper reports the neutron-irradiation-induced effects on the microstructure of NBG-18 and IG-110 nuclear graphites. The high-temperature neutron irradiation at two different irradiation conditions was carried out at the Advanced Test Reactor National User Facility at the Idaho National Laboratory. NBG-18 samples were irradiated to 1.54 dpa and 6.78 dpa at 430 °C and 678 °C respectively. IG-110 samples were irradiated to 1.91 dpa and 6.70 dpa at 451 °C and 674 °C respectively. Bright-field transmission electron microscopy imaging was used to study the changes in different microstructural components such as filler particles, microcracks, binder and quinoline-insoluble (QI) particles. Significant changes have been observed in samples irradiated to about 6.7 dpa. The closing of pre-existing microcracks was observed in both the filler and the binder phases. The binder phase exhibited substantial densification with near complete elimination of the microcracks. The QI particles embedded in the binder phase exhibited a complete microstructural transformation from rosettes to highly crystalline solid spheres. The lattice images indicate the formation of edge dislocations as well as extended line defects bridging the adjacent basal planes. The positive climb of these dislocations has been identified as the main contributor to the irradiation-induced swelling of the graphite lattice.

  11. Preparations and characterizations of novel graphite-like materials and some high oxidation state fluorine chemistry

    SciTech Connect (OSTI)

    Shen, Ciping

    1992-11-01

    Novel graphite-like materials, BC{sub x} (6>x{ge}3), have been prepared using BCl{sub 3} and C{sub 6}H{sub 6} at 800--1000C, and C{sub x}N (14>x{ge}5) have been synthesized using C{sub 5}H{sub 5}N and Cl{sub 2} at 680C--986C. Bulk and thin film characterization were used to study the structure and bonding in these solids. C{sub 8}K(NH{sub 3}){sub 1.1} was prepared by reacting C{sub 8}K with gaseous NH{sub 3}. The carbon sub-lattice is hexagonal: a = 2.47 {Angstrom}, c = 6.47 {Angstrom}. The smaller a parameter and lower conductivity are attributed to smaller electron transfer from K to the conduction band solvation of K by NH{sub 3}. A simplified liquid phase method for synthesizing Li-graphite intercalation compounds has been developed; synthesis of a lamellar mixed conductor, C{sub x}{sup +}Li{sub 2}N{sup {minus}}, has been attempted. Stability and conductivity of (BN){sub 3}SO{sub 3}F have been studied; it was shown to be metallic with a specific conductivity of 1.5 S{center_dot}cm{sup {minus}1}. Its low conductivity is attributed to the low mobility of holes in BN sheets.

  12. The shear fracture toughness, KIIc, of graphite

    SciTech Connect (OSTI)

    Burchell, Timothy D.; Erdman, III, Donald L.

    2015-11-05

    In this study, the critical shear stress intensity factor, KIIc, here-in referred to as the shear fracture toughness, KIIc (MPa m), of two grades of graphite are reported. The range of specimen volumes was selected to elucidate any specimen size effect, but smaller volume specimen tests were largely unsuccessful, shear failure did not occur between the notches as expected. This was probably due to the specimen geometry causing the shear fracture stress to exceed the compressive failure stress. In subsequent testing the specimen geometry was altered to reduce the compressive footprint and the notches (slits) made deeper to reduce the specimen's ligament length. Additionally, we added the collection of Acoustic Emission (AE) during testing to assist with the identification of the shear fracture load. The means of KIIc from large specimens for PCEA and NBG-18 are 2.26 MPa m with an SD of 0.37 MPa m and 2.20 MPa m with an SD of 0.53 MPa m, respectively. The value of KIIc for both graphite grades was similar, although the scatter was large. In this work we found the ratio of KIIc/KIc ≈ 1.6. .

  13. Pre-conceptual Development and characterization of an extruded graphite composite fuel for the TREAT Reactor

    SciTech Connect (OSTI)

    Luther, Erik; Rooyen, Isabella van; Leckie, Rafael; Papin, Pallas; Nelson, Andrew; Hunter, James

    2015-03-01

    In an effort to explore fuel systems that are more robust under accident scenarios, the DOE-NE has identified the need to resume transient testing. The Transient Reactor Test (TREAT) facility has been identified as the preferred option for the resumption of transient testing of nuclear fuel in the United States. In parallel, NNSA’s Global Threat Reduction Initiative (GTRI) Convert program is exploring the needs to replace the existing highly enriched uranium (HEU) core with low enriched uranium (LEU) core. In order to construct a new LEU core, materials and fabrication processes similar to those used in the initial core fabrication must be identified, developed and characterized. In this research, graphite matrix fuel blocks were extruded and materials properties of were measured. Initially the extrusion process followed the historic route; however, the project was expanded to explore methods to increase the graphite content of the fuel blocks and explore modern resins. Materials properties relevant to fuel performance including density, heat capacity and thermal diffusivity were measured. The relationship between process defects and materials properties will be discussed.

  14. Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

    SciTech Connect (OSTI)

    Bruce G. Schnitzler; Stanley K. Borowski

    2012-07-01

    Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified as the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine operations and the engine and stage design were constrained to fit within the payload volume of the then planned space shuttle. The SNRE core design utilized hexagonal fuel elements and hexagonal structural support elements. The total number of elements can be varied to achieve engine designs of higher or lower thrust levels. Some variation in the ratio of fuel elements to structural elements is also possible. Options for SNRE-based engine designs in the 25,000-lbf thrust range were described in a recent (2010) Joint Propulsion Conference paper. The reported designs met or exceeded the performance characteristics baselined in the DRA 5.0 Study. Lower thrust SNRE-based designs were also described in a recent (2011) Joint Propulsion Conference paper. Recent activities have included parallel evaluation and design efforts on fast spectrum engines employing refractory metal alloy fuels. These efforts include evaluation of both heritage designs from the Argonne National Laboratory (ANL) and General Electric Company GE-710 Programs as well as more recent designs. Results are presented for a number of not-yet optimized fast spectrum engine options.

  15. Mapping Suitability Areas for Concentrated Solar Power Plants Using Remote Sensing Data

    SciTech Connect (OSTI)

    Omitaomu, Olufemi A; Singh, Nagendra; Bhaduri, Budhendra L

    2015-01-01

    The political push to increase power generation from renewable sources such as solar energy requires knowing the best places to site new solar power plants with respect to the applicable regulatory, operational, engineering, environmental, and socioeconomic criteria. Therefore, in this paper, we present applications of remote sensing data for mapping suitability areas for concentrated solar power plants. Our approach uses digital elevation model derived from NASA s Shuttle Radar Topographic Mission (SRTM) at a resolution of 3 arc second (approx. 90m resolution) for estimating global solar radiation for the study area. Then, we develop a computational model built on a Geographic Information System (GIS) platform that divides the study area into a grid of cells and estimates site suitability value for each cell by computing a list of metrics based on applicable siting requirements using GIS data. The computed metrics include population density, solar energy potential, federal lands, and hazardous facilities. Overall, some 30 GIS data are used to compute eight metrics. The site suitability value for each cell is computed as an algebraic sum of all metrics for the cell with the assumption that all metrics have equal weight. Finally, we color each cell according to its suitability value. We present results for concentrated solar power that drives a stream turbine and parabolic mirror connected to a Stirling Engine.

  16. Mapping suitability areas for concentrated solar power plants using remote sensing data

    SciTech Connect (OSTI)

    Omitaomu, Olufemi A.; Singh, Nagendra; Bhaduri, Budhendra L.

    2015-05-14

    The political push to increase power generation from renewable sources such as solar energy requires knowing the best places to site new solar power plants with respect to the applicable regulatory, operational, engineering, environmental, and socioeconomic criteria. Therefore, in this paper, we present applications of remote sensing data for mapping suitability areas for concentrated solar power plants. Our approach uses digital elevation model derived from NASA s Shuttle Radar Topographic Mission (SRTM) at a resolution of 3 arc second (approx. 90m resolution) for estimating global solar radiation for the study area. Then, we develop a computational model built on a Geographic Information System (GIS) platform that divides the study area into a grid of cells and estimates site suitability value for each cell by computing a list of metrics based on applicable siting requirements using GIS data. The computed metrics include population density, solar energy potential, federal lands, and hazardous facilities. Overall, some 30 GIS data are used to compute eight metrics. The site suitability value for each cell is computed as an algebraic sum of all metrics for the cell with the assumption that all metrics have equal weight. Finally, we color each cell according to its suitability value. Furthermore, we present results for concentrated solar power that drives a stream turbine and parabolic mirror connected to a Stirling Engine.

  17. Binding and Diffusion of Lithium in Graphite: Quantum Monte-Carlo benchmarks and validation of van der Waals density functional methods

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

    Ganesh, Panchapakesan; Kim, Jeongnim; Park, Changwon; Yoon, Mina; Reboredo, Fernando A; Kent, Paul R

    2014-01-01

    Highly accurate diffusion quantum Monte Carlo (QMC) studies of the adsorption and diffusion of atomic lithium in AA-stacked graphite are compared with van der Waals-including density functional theory (DFT) calculations. Predicted QMC lattice constants for pure AA graphite agree with experiment. Pure AA-stacked graphite is shown to challenge many van der Waals methods even when they are accurate for conventional AB graphite. Highest overall DFT accuracy, considering pure AA-stacked graphite as well as lithium binding and diffusion, is obtained by the self-consistent van der Waals functional vdW-DF2, although errors in binding energies remain. Empirical approaches based on point charges suchmore » as DFT-D are inaccurate unless the local charge transfer is assessed. The results demonstrate that the lithium carbon system requires a simultaneous highly accurate description of both charge transfer and van der Waals interactions, favoring self-consistent approaches.« less

  18. Real Time Selective Harmonic Minimization for Multilevel Inverters Connected to Solar Panels Using Artificial Neural Network Angle Generation

    SciTech Connect (OSTI)

    Tolbert, Leon M; Ozpineci, Burak; Filho, Faete; Cao, Yue

    2011-01-01

    This work approximates the selective harmonic elimination problem using artificial neural networks (ANNs) to generate the switching angles in an 11-level full-bridge cascade inverter powered by five varying dc input sources. Each of the five full bridges of the cascade inverter was connected to a separate 195-W solar panel. The angles were chosen such that the fundamental was kept constant and the low-order harmonics were minimized or eliminated. A nondeterministic method is used to solve the system for the angles and to obtain the data set for the ANN training. The method also provides a set of acceptable solutions in the space where solutions do not exist by analytical methods. The trained ANN is a suitable tool that brings a small generalization effect on the angles' precision and is able to perform in real time (50-/60-Hz time window).

  19. Near-critical phase explosion promoting breakdown plasma ignition during laser ablation of graphite

    SciTech Connect (OSTI)

    Ionin, A. A.; Kudryashov, S. I.; Seleznev, L. V.

    2010-07-15

    Removal rate, air shock, and ablative recoil pressure parameters were measured as a function of laser intensity I{sub peak} during nanosecond laser ablation of graphite. Surface vaporization of molten graphite at low intensities I{sub peak}<0.15 GW/cm{sup 2} was observed to transform into its near-critical phase explosion (intense homogeneous boiling) at the threshold intensity I{sub PE}approx =0.15 GW/cm{sup 2} in the form of a drastic, correlated rise of removal rate, air shock, and ablative recoil pressure magnitudes. Just above this threshold (I{sub peak}>=0.25 GW/cm{sup 2}), the explosive mass removal ended up with saturation of the removal rate, much slower increase of the air and recoil pressure magnitudes, and appearance of a visible surface plasma spark. In this regime, the measured far-field air shock pressure amplitude exhibits a sublinear dependence on laser intensity (propor toI{sub peak}{sup 4/9}), while the source plasma shock pressure demonstrates a sublinear trend (propor toI{sub peak}{sup 3/4}), both indicating the subcritical character of the plasma. Against expectations, in this regime the plasma recoil pressure increases versus I{sub peak} superlinearly (propor toI{sub peak}{sup 1.1}), rather than sublinearly (propor toI{sub peak}{sup 3/4}), with the mentioned difference related to the intensity-dependent initial spatial plasma dimensions within the laser waist on the graphite surface and to the plasma formation time during the heating laser pulse (overall, the pressure source effect). The strict coincidence of the phase explosion, providing high (kbar) hydrodynamic pressures of ablation products, and the ignition of ablative laser plasma in the carbon plume may indicate the ablative pressure-dependent character of the underlying optical breakdown at the high plume pressures, initiating the plasma formation. The experimental data evidence that the spatiotemporal extension of the plasma in the laser plume and ambient air during the heating laser pulse is supported by fast lateral electron and radiative heat conduction (laser-supported combustion wave regime), rather than by propagation of a strong shock wave (laser-supported detonation wave regime).

  20. Application of artificial neural networks in power system security and vulnerability assessment

    SciTech Connect (OSTI)

    Qin Zhou; Davidson, J.; Fouad, A.A.

    1994-02-01

    In a companion paper the concept of system vulnerability is introduced as a new framework for power system dynamic security assessment. Using the TEF method of transient stability analysis, the energy margin [Delta]V is used as an indicator of the level of security, and its sensitivity to a changing system parameter p ([partial derivative][Delta]V/[partial derivative]p) as indicator of its trend with changing system conditions. These two indicators are combined to determine the degree of system vulnerability to contingent disturbances in a stability-limited power system. Thresholds for acceptable levels of the security indicator and its trend are related to the stability limits of a critical system parameter (plant generation limits). Operating practices and policies are used to determine these thresholds. In this paper the artificial neural networks (ANNs) technique is applied to the concept of system vulnerability within the recently developed framework, for fast pattern recognition and classification of system dynamic security status. A suitable topology for the neural network is developed, and the appropriate training method and input and output signals are selected. The procedure developed is successfully applied to the IEEE 50-generator test system. Data previously obtained by heuristic techniques are used for training the ANN.

  1. Temperature programed desorption of C{sub 2}H{sub 4} from pure and graphite-covered Pt(111)

    SciTech Connect (OSTI)

    Vermang, B.; Juel, M.; Raaen, S.

    2007-11-15

    Ethylene adsorption on Pt(111) at 95 K was studied by temperature programed desorption (TPD), low energy electron diffraction (LEED), and x-ray photoelectron spectroscopy. Ethylene desorbs reversibly at 112 K and irreversibly at 255 and 280 K. It is generally accepted that annealing of ethylene adsorbed on Pt(111) to 300 K results in a dehydrogenation to ethylidyne through an ethylidene intermediate. This was observed by a hydrogen desorption peak at 300 K. Also, hydrogenation of the adsorbed ethylene was observed by a small ethane desorption peak at 300 K. Upon heating to 700 K, the ethylidyne species will further dehydrogenate to carbidic carbon species with hydrogen desorption peaks at 460 and 640 K. If the carbidic species is heated to higher temperatures (up to 1000 K), it will further dehydrogenate and form graphitic islands which will accumulate by Ostwald ripening in larger islands at the step edges of the surface. After annealing the sample to 1000 K, a statistically distributed 8x8 superstructure of these graphite islands is achieved, as interpreted from A pattern in the LEED data. The TPD results indicate that ethylene adsorption on Pt(111) results in the formation of graphitic islands upon heating to 1000 K, contrary to previous conjectures of formation of a full graphite monolayer.

  2. Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

    SciTech Connect (OSTI)

    Gayathri, S.; Jayabal, P.; Ramakrishnan, V., E-mail: vr.optics1@gmail.com [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai-625021, India. (India); Kottaisamy, M. [Department of Chemistry, Thiagarajar College of Engineering, Madurai-625015, India. (India)] [Department of Chemistry, Thiagarajar College of Engineering, Madurai-625015, India. (India)

    2014-02-15

    The exfoliation of graphene from pristine graphite in a liquid phase was achieved successfully via sonication followed by centrifugation method. Ultravioletvisible (UVvis) spectra of the obtained graphene dispersions at different exfoliation time indicated that the concentration of graphene dispersion increased markedly with increasing exfoliation time. The sheet-like morphology of the exfoliated graphene was revealed by Scanning Electron Microscopy (SEM) image. Further, the morphological change in different exfoliation time was investigated by Atomic Force Microscopy (AFM). A complete structural and defect characterization was probed using micro-Raman spectroscopic technique. The shape and position of the 2D band of Raman spectra revealed the formation of bilayer to few layer graphene. Also, Raman mapping confirmed the presence of uniformly distributed bilayer graphene sheets on the substrate.

  3. Relation between the overpotentials and structures of graphite fluoride electrode in nonaqueous lithium cell

    SciTech Connect (OSTI)

    Watanabe, N.; Hagiwara, R.; Nakajima, T.

    1984-09-01

    A study was made of the relation between the cathode overpotentials and structures of two kinds of graphite fluorides, (CF)n and (C2F)n in a nonaqueous lithium battery. The overpotential of (CF)n electrode decreased with increasing interlayer spacing and decreasing thickness of the crystallite along the C axis. However, it was found that the overpotential of (C2F)n electrode primarily depended on the amount of the defects which would be present in the form of polynuclear aromatic carbon rings in (C2F)n. The defects in (C2F)n would give the short circuiting paths for the transfer of a lithium ion in diffusion layer. The higher discharge potential of (C2F)n than that of (CF)n was mainly attributed to the effect of the defects contained in (C2F)n. 17 references.

  4. The effect of 150?m expandable graphite on char expansion of intumescent fire retardant coating

    SciTech Connect (OSTI)

    Ullah, Sami Shariff, A. M. E-mail: azmibustam@petronas.com.my; Bustam, M. A. E-mail: azmibustam@petronas.com.my; Ahmad, Faiz

    2014-10-24

    Intumescent is defined as the swelling of certain substances to insulate the underlying substrate when they are heated. In this research work the effect of 150?m expandable graphite (EG) was studied on char expansion, char morphology and char composition of intumescent coating formulations (ICFs). To study the expansion and thermal properties of the coating, nine different formulations were prepared. The coatings were tested at 500 C for one hour and physically were found very stable and well bound with the steel substrate. The morphology was studied by Scanning Electron Microscopy (SEM). The char composition was analysed by X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. EG above than 10.8wt% expands the char abruptly with uniform network structure and affect the outer surface of the char.

  5. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOE Patents [OSTI]

    Ardary, Z.L.; Benton, S.T.

    1988-11-22

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  6. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOE Patents [OSTI]

    Ardary, Z.L.; Benton, S.T.

    1987-07-08

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  7. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOE Patents [OSTI]

    Ardary, Zane L.; Benton, Samuel T.

    1988-01-01

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  8. Particle production of a graphite target system for the intensity frontier

    SciTech Connect (OSTI)

    Ding, X.; Kirk, H.; McDonald, K. T.

    2015-05-03

    A solid graphite target system is considered for an intense muon and/or neutrino source in support of physics at the intensity frontier. We previously optimized the geometric parameters of the beam and target to maximize particle production at low energies by incoming protons with kinetic energy of 6.75 GeV and an rms geometric emittance of 5 mm-mrad using the MARS15(2014) code. In this study, we ran MARS15 with ROOT-based geometry and also considered a mercury-jet target as an upgrade option. The optimization was extended to focused proton beams with transverse emittances from 5 to 50 mm-mrad, showing that the particle production decreases slowly with increasing emittance. We also studied beam-dump configurations to suppress the rate of undesirable high-energy secondary particles in the beam.

  9. Bias-dependent molecular-level structure of electrical double layer in ionic liquid on graphite

    SciTech Connect (OSTI)

    Black, Jennifer M; Walters, Deron; Labuda, Aleksander; Feng, Guang; Hillesheim, Patrick C; Dai, Sheng; Cummings, Peter T; Kalinin, Sergei V; Proksch, Roger; Balke, Nina

    2013-01-01

    Bias-dependent structure of electrochemical double layers at liquid-solid interfaces underpin a multitude of phenomena in virtually all areas of scientific enquiry ranging from energy storage and conversion systems, biology, to geophysics and geochemistry. Here we report the bias-evolution of the electric double layer structure of an ionic liquid on highly ordered pyrolytic graphite as a model system for carbon-based electrodes for electrochemical supercapacitors measured by atomic force microscopy. Matching the observed structures to molecular dynamics simulations allows us to resolve steric effects due to cation and anion layers. We observe reconfiguration under applied bias and the orientational transitions in the Stern layer. The synergy between molecular dynamics simulation and experiment provides a comprehensive picture of structural phenomena and long- and short range interactions. This insight will improve understanding of the mechanism of charge storage in electrochemical capacitors on a molecular level which can be used to enhance their electrochemical performance.

  10. 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

    2008-12-01

    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.

  11. Disposal options for burner ash from spent graphite fuel. Final study report November 1993

    SciTech Connect (OSTI)

    Pinto, A.P.

    1994-08-01

    Three major disposal alternatives are being considered for Fort St. Vrain Reactor (FSVR) and Peach Bottom Reactor (PBR) spent fuels: direct disposal of packaged, intact spent fuel elements; (2) removal of compacts to separate fuel into high-level waste (HLW) and low-level waste (LLW); and (3) physical/chemical processing to reduce waste volumes and produce stable waste forms. For the third alternative, combustion of fuel matrix graphite and fuel particle carbon coatings is a preferred technique for head-end processing as well as for volume reduction and chemical pretreatment prior to final fixation, packaging, and disposal of radioactive residuals (fissile and fertile materials together with fission and activation products) in a final repository. This report presents the results of a scoping study of alternate means for processing and/or disposal of fissile-bearing particles and ash remaining after combustion of FSVR and PBR spent graphite fuels. Candidate spent fuel ash (SFA) waste forms in decreasing order of estimated technical feasibility include glass-ceramics (GCs), polycrystalline ceramic assemblages (PCAs), and homogeneous amorphous glass. Candidate SFA waste form production processes in increasing order of estimated effort and cost for implementation are: low-density GCs via fuel grinding and simultaneous combustion and waste form production in a slagging cyclone combustor (SCC); glass or low-density GCs via fluidized bed SFA production followed by conventional melting of SFA and frit; PCAs via fluidized bed SFA production followed by hot isostatic pressing (HIPing) of SFA/frit mixtures; and high-density GCs via fluidized bed SFA production followed by HIPing of Calcine/Frit/SFA mixtures.

  12. Mass transfer during wall-rock alteration: An example from a quartz-graphite vein, Black Hills, South Dakota

    SciTech Connect (OSTI)

    Galbreath, K.C.; Duke, E.F.; Papike, J.J. ); Laul, J.C. )

    1988-07-01

    Mass transfer and fluid-rock interaction have been evaluated along two sample traverses in low-sillimanite grade quartz-mica schist adjacent to a synmetamorphic quartz-graphite vein in the southern Black Hills, South Dakota. In an {approximately}17 cm halo between apparently unaltered schist and the vein contact is an outer zone of cryptic alteration and three inner zones of visible alteration. The cryptic zone consists of the original prograde metamorphic mineral assemblage plus anomalously high amounts of tourmaline. The outermost visible zone contains abundant graphite. The second visible zone is defined by intensive bleaching of the schist. The innermost visible zone, immediately adjacent to the vein, is tourmaline + quartz + plagioclase + limonite + graphite. The vein is composed almost entirely of quartz, but also contains trace amounts of graphite. Mass balance calculations indicate that Al was essentially inert. The predominant chemical changes during wall-rock alteration were addition of B and C from the vein-forming fluid along with loss of K from the wall rocks, corresponding to precipitation of tourmaline and graphite, and the progressive destruction of microcline, biotite, and muscovite toward the vein. In addition, the elements V, Cr, Cu, Zn, Pb, As, Sb, W, and Au were introduced into the country rock, whereas Si, Rb, Ba, and Cs were removed. Fluid-rock interaction modeling suggests that between one and four equivalent masses of fluid interacted chemically with the most altered mineral assemblages. In addition, greater than one equivalent mass of reactive fluid penetrated to distances of at least 5 cm from the vein contact.

  13. Estimating Rooftop Suitability for PV: A Review of Methods, Patents, and Validation Techniques

    SciTech Connect (OSTI)

    Melius, J.; Margolis, R.; Ong, S.

    2013-12-01

    A number of methods have been developed using remote sensing data to estimate rooftop area suitable for the installation of photovoltaics (PV) at various geospatial resolutions. This report reviews the literature and patents on methods for estimating rooftop-area appropriate for PV, including constant-value methods, manual selection methods, and GIS-based methods. This report also presents NREL's proposed method for estimating suitable rooftop area for PV using Light Detection and Ranging (LiDAR) data in conjunction with a GIS model to predict areas with appropriate slope, orientation, and sunlight. NREL's method is validated against solar installation data from New Jersey, Colorado, and California to compare modeled results to actual on-the-ground measurements.

  14. Synthetic nanotubes lay foundation for new technology: Artificial pores

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

    mimic key features of natural pores | Argonne National Laboratory Synthetic nanotubes lay foundation for new technology: Artificial pores mimic key features of natural pores By Tona Kunz * July 17, 2012 Tweet EmailPrint Scientists have overcome key design hurdles to expand the potential uses of nanopores and nanotubes. The creation of smart nanotubes with selective mass transport opens up a wider range of applications for water purification, chemical separation and fighting disease.

  15. Emergence of Artificial Photons in an Optical Lattice

    SciTech Connect (OSTI)

    Tewari, Sumanta; Scarola, V. W.; Sarma, S. Das; Senthil, T.

    2006-11-17

    We establish the theoretical feasibility of direct analog simulation of the compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We discuss the realizability of the topological Coulomb phase in extended Bose-Hubbard models in several optical lattice geometries. We predict the testable signatures of this emergent phase in noise correlation measurements, thus suggesting the possible emergence of artificial light in optical lattices.

  16. Artificial Cells for Advanced Drug Delivery - Energy Innovation Portal

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

    Biomass and Biofuels Biomass and Biofuels Find More Like This Return to Search Artificial Cells for Advanced Drug Delivery Colorado School of Mines Contact CSM About This Technology Technology Marketing SummaryThis invention takes advantage of the unique surface chemistry of a ZnO crystalline nanostructure to catalyze a variety of chemical reactions. DescriptionOne such reaction is the hydrogenation of carbon dioxide to methanol. Alcohols interacts both molecularly and dissociatively with the

  17. Advanced Artificial Science. The development of an artificial science and engineering research infrastructure to facilitate innovative computational modeling, analysis, and application to interdisciplinary areas of scientific investigation.

    SciTech Connect (OSTI)

    Saffer, Shelley I.

    2014-12-01

    This is a final report of the DOE award DE-SC0001132, Advanced Artificial Science. The development of an artificial science and engineering research infrastructure to facilitate innovative computational modeling, analysis, and application to interdisciplinary areas of scientific investigation. This document describes the achievements of the goals, and resulting research made possible by this award.

  18. Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    DOE Patents [OSTI]

    Ray, S.P.; Rapp, R.A.

    1984-06-12

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

  19. Evaluation of Suitability of Selected Set of Coal Plant Sites for Repowering with Small Modular Reactors

    SciTech Connect (OSTI)

    Belles, Randy; Copinger, Donald A; Mays, Gary T; Omitaomu, Olufemi A; Poore III, Willis P

    2013-03-01

    This report summarizes the approach that ORNL developed for screening a sample set of small coal stations for possible repowering with SMRs; the methodology employed, including spatial modeling; and initial results for these sample plants. The objective in conducting this type of siting evaluation is to demonstrate the capability to characterize specific sample coal plant sites to identify any particular issues associated with repowering existing coal stations with SMRs using OR-SAGE; it is not intended to be a definitive assessment per se as to the absolute suitability of any particular site.

  20. Development of a Habitat Suitability Index Model for the Sage Sparrow on the Hanford Site

    SciTech Connect (OSTI)

    Duberstein, Corey A.; Simmons, Mary Ann; Sackschewsky, Michael R.; Becker, James M.

    2008-01-01

    Mitigation threshold guidelines for the Hanford Site are based on habitat requirements of the sage sparrow (Amphispiza belli) and only apply to areas with a mature sagebrush (Artemisia tridentata) overstory and a native understory. The sage sparrow habitat requirements are based on literature values and are not specific to the Hanford Site. To refine these guidelines for the Site, a multi-year study was undertaken to quantify habitat characteristics of sage sparrow territories. These characteristics were then used to develop a habitat suitability index (HSI) model which can be used to estimate the habitat value of specific locations on the Site.

  1. EFFECTS OF GRAPHITE SURFACE ROUGHNESS ON BYPASS FLOW COMPUTATIONS FOR AN HTGR

    SciTech Connect (OSTI)

    Rich Johnson; Yu-Hsin Tung; Hiroyuki Sato

    2011-07-01

    Bypass flow in a prismatic high temperature gas reactor (HTGR) occurs between graphite blocks as they sit side by side in the core. Bypass flow is not intentionally designed to occur in the reactor, but is present because of tolerances in manufacture, imperfect installation and expansion and shrinkage of the blocks from heating and irradiation. It is desired to increase the knowledge of the effects of such flow, which has been estimated to be as much as 20% of the total helium coolant flow. Computational fluid dynamic (CFD) simulations can provide estimates of the scale and impacts of bypass flow. Previous CFD calculations have examined the effects of bypass gap width, level and distribution of heat generation and effects of shrinkage. The present contribution examines the effects of graphite surface roughness on the bypass flow for different relative roughness factors on three gap widths. Such calculations should be validated using specific bypass flow measurements. While such experiments are currently underway for the specific reference prismatic HTGR design for the next generation nuclear plant (NGNP) program of the U. S. Dept. of Energy, the data are not yet available. To enhance confidence in the present calculations, wall shear stress and heat transfer results for several turbulence models and their associated wall treatments are first compared for flow in a single tube that is representative of a coolant channel in the prismatic HTGR core. The results are compared to published correlations for wall shear stress and Nusselt number in turbulent pipe flow. Turbulence models that perform well are then used to make bypass flow calculations in a symmetric onetwelfth sector of a prismatic block that includes bypass flow. The comparison of shear stress and Nusselt number results with published correlations constitutes a partial validation of the CFD model. Calculations are also compared to ones made previously using a different CFD code. Results indicate that increasing surface roughness increases the maximum fuel and helium temperatures as do increases in gap width. However, maximum coolant temperature variation due to increased gap width is not changed by surface roughness.

  2. Functionalization/passivation of porous graphitic carbon with di-tert-amylperoxide

    SciTech Connect (OSTI)

    Jensen, David S.; Gupta, Vipul; Olsen, Rebecca E.; Miller, Alex T.; Davis, Robert C.; Ess, Daniel; Zhu, Zihua; Vail, Michael A.; Dadson, Andrew; Linford, Matthew R.

    2011-11-18

    Porous graphitic carbon (PGC) particles were functionalized/passivated in situ in packed beds at elevated temperature with neat di-tert-amylperoxide (DTAP) in a column oven. The performance of these particles for high performance liquid chromatography (HPLC) was assayed before and after this chemistry with the following analytes: benzene, toluene, ethyl benzene, n-propyl benzene, n-butyl benzene, p-xylene, phenol, 4-methylphenol, phenetole, 3,5-xylenol, and anisole. After the first functionalization/passivation, the retention factors, k, of these compounds decreased by about 5% and the number of theoretical plates (N) increased by ca. 15%. These values of k then remained roughly constant after a second functionalization/ passivation but a further increase in N was noticed. In addition, after each of the reactions, the peak asymmetries decreased by ca. 15%, for a total of ca. 30%. The columns were then subjected twice to methanol at 100 C for 5 h at 1 mL/min. After these stability tests, the values of k remained roughly constant, the number of plates increased, which is favorable, and the asymmetries rose and then declined, where they remained below the initial values for the unfunctionalized columns. Functionalized and unfunctionalized particles were characterized by scanning electron microscopy and BET measurements, which showed no difference between the functionalized and unfunctionalized materials, and X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS), where ToF-SIMS suggested some chemical differences between the functionalized and unfunctionalized materials. In particular ToF-SIMS suggested that the expected five-carbon fragments from DTAP exist at higher concentrations on DTAP-functionalized PGC. First principle calculations on model graphitic surfaces suggest that the first addition of a DTAP radical to the surface proceeds in an approximately isothermal or slightly favorable fashion, but that subsequent DTAP additions are then increasingly thermodynamically favorable. Thus, this analysis suggests that the direct functionalization/passivation of PGC with DTAP is plausible. Chemometric analyses of the chromatographic and ToF-SIMS data are also presented.

  3. Carbide Coatings for Nickel Alloys, Graphite and Carbon/Carbon Composites to be used in Fluoride Salt Valves

    SciTech Connect (OSTI)

    Nagle, Denis; Zhang, Dajie

    2015-10-22

    The focus of this research was concerned with developing materials technology that supports the evolution of Generation IV Advanced High Temperature Reactor (AHTR) concepts. Specifically, we investigate refractory carbide coatings for 1) nickel alloys, and 2) commercial carbon-carbon composites (CCCs). Numerous compelling reasons have driven us to focus on carbon and carbide materials. First, unlike metals, the strength and modulus of CCCs increase with rising temperature. Secondly, graphite and carbon composites have been proven effective for resisting highly corrosive fluoride melts such as molten cryolite [Na₃AlF₆] at ~1000°C in aluminum reduction cells. Thirdly, graphite and carbide materials exhibit extraordinary radiation damage tolerance and stability up to 2000°C. Finally, carbides are thermodynamically more stable in liquid fluoride salt than the corresponding metals (i.e. Cr and Zr) found in nickel based alloys.

  4. Researching Fe catalyst suitable for CO{sub 2}-containing syngas for Fischer-Tropsch synthesis

    SciTech Connect (OSTI)

    Wensheng Ning; Naoto Koizumi; Muneyoshi Yamada

    2009-09-15

    Fischer-Tropsch (FT) synthesis is a technology to produce liquid fuels from coal, natural gas, and biomass as an alternate to crude oil. However, the quantity of emitted CO{sub 2} from the FT process consisting of syngas preparation, FT synthesis, and product workup is one of the serious disadvantages of FT process. The conversion of CO{sub 2} into hydrocarbons is one of the promising methods to decrease CO{sub 2} emissions. Effects of promoter addition on the activity of precipitated Fe catalysts for the conversion of CO{sub 2} were studied using pure CO{sub 2} and CO{sub 2}-containing syngas feeds. The results suggested that CO{sub 2} can be activated by suitable promoter(s) for hydrocarbon synthesis at low temperature. Low K content is suitable for increasing hydrocarbon yield. The Fe catalysts promoted by equal Zn and Cu have higher CO and CO{sub 2} conversion and decreased CH{sub 4} selectivity. 36 refs., 7 figs., 3 tabs.

  5. Evidence for graphite-like hexagonal AlN nanosheets epitaxially grown on single crystal Ag(111)

    SciTech Connect (OSTI)

    Tsipas, P.; Kassavetis, S.; Tsoutsou, D.; Xenogiannopoulou, E.; Golias, E.; Giamini, S. A.; Dimoulas, A.; Grazianetti, C.; Fanciulli, M.; Dipartimento di Scienza dei Materiali, Universit degli Studi di Milano Bicocca, I-20126, Milano ; Chiappe, D.; Molle, A.

    2013-12-16

    Ultrathin (sub-monolayer to 12 monolayers) AlN nanosheets are grown epitaxially by plasma assisted molecular beam epitaxy on Ag(111) single crystals. Electron diffraction and scanning tunneling microscopy provide evidence that AlN on Ag adopts a graphite-like hexagonal structure with a larger lattice constant compared to bulk-like wurtzite AlN. This claim is further supported by ultraviolet photoelectron spectroscopy indicating a reduced energy bandgap as expected for hexagonal AlN.

  6. Communication: Separable potential energy surfaces from multiplicative artificial neural networks

    SciTech Connect (OSTI)

    Koch, Werner, E-mail: wkoch@thethirdrock.net; Zhang, Dong H. [State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian (China)

    2014-07-14

    We present a potential energy surface fitting scheme based on multiplicative artificial neural networks. It has the sum of products form required for efficient computation of the dynamics of multidimensional quantum systems with the multi configuration time dependent Hartree method. Moreover, it results in analytic potential energy matrix elements when combined with quantum dynamics methods using Gaussian basis functions, eliminating the need for a local harmonic approximation. Scaling behavior with respect to the complexity of the potential as well as the requested accuracy is discussed.

  7. Nanoscale topographical replication of graphene architecture by artificial DNA nanostructures

    SciTech Connect (OSTI)

    Moon, Y.; Seo, S.; Park, J.; Park, T.; Ahn, J. R., E-mail: jrahn@skku.edu [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Shin, J.; Dugasani, S. R. [Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Woo, S. H. [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Park, S. H., E-mail: sunghapark@skku.edu [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-06-09

    Despite many studies on how geometry can be used to control the electronic properties of graphene, certain limitations to fabrication of designed graphene nanostructures exist. Here, we demonstrate controlled topographical replication of graphene by artificial deoxyribonucleic acid (DNA) nanostructures. Owing to the high degree of geometrical freedom of DNA nanostructures, we controlled the nanoscale topography of graphene. The topography of graphene replicated from DNA nanostructures showed enhanced thermal stability and revealed an interesting negative temperature coefficient of sheet resistivity when underlying DNA nanostructures were denatured at high temperatures.

  8. Subtask 4: Artificial reaction center-antenna complex | Center for

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

    Bio-Inspired Solar Fuel Production 4: Artificial reaction center-antenna complex All papers by year Subtask 1 Subtask 2 Subtask 3 Subtask 4 Subtask 5 Megiatto, J.D., Méndez-Hernández, D.D., Tejeda-Ferrari, M.E., Teillout, A.-L., Llansola-Portolés, M.J., Kodis, G., Poluektov, O.G., Rajh, T., Mujica, V., Groy, T. L., Gust, D., Moore, T.A., Moore, A.L. (2014) A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II, Nature Chemistry, 6, 423-428,

  9. On the relation between the overpotentials and structures of graphite fluoride electrode in nonaqueous lithium cell

    SciTech Connect (OSTI)

    Watanabe, N.; Hayiwara, R.; Nakajima, T.

    1984-09-01

    A study was made of the relation between the cathode overpotentials and structures of two kinds of graphite fluorides, (CF)/SUB n/ and (C/sub 2/F)/SUB n/ in nonaqueous lithium battery. The overpotential of (CF)/SUB n/ electrode decreased with increasing interlayer spacing and decreasing thickness of the crystallite along the C axis. However, it was found that the overpotential of (C/sub 2/F)/SUB n/ electrode primarily depended on the amount of the defects which would be present in the form of polynuclear aromatic carbon rings in (C/sub 2/F)/SUB n/. The defects in (C/sub 2/F)/SUB n/ would give the short circuiting paths for the transfer of a lithium ion in diffusion layer. The higher discharge potential of (C/sub 2/F)/SUB n/ than that of (CF)/SUB n/ was mainly attributed to the effect of the defects contained in (C/sub 2/F)/SUB n/.

  10. Measurements of Aerosol Charge and Size Distribution for Graphite, Gold, Palladium, and Silver Nanoparticles

    SciTech Connect (OSTI)

    Simones, Matthew P.; Gutti, Veera R.; Meyer, Ryan M.; Loyalka, Sudarshan K.

    2011-11-01

    The role of charge on aerosol evolution and hence the nuclear source term has been an issue of interest, and there is a need for both experimental techniques and modeling for quantifying this role. Our focus here is on further exploration of a tandem differential mobility analyzer (TDMA) technique to simultaneously measure both the size and charge (positive, negative and neutral) dependent aerosol distributions. We have generated graphite, gold, silver, and palladium nanoparticles (aerosol) using a spark generator. We measure the electrical mobility-size distributions for these aerosols using a TDMA, and from these data we deduce the full charge-size distributions. We observe asymmetry in the particle size distributions for negative and positive charges. This asymmetry could have a bearing on the dynamics of charged aerosols, indicating that the assumption of symmetry for size distributions of negatively and positively charged particles in source term simulations may not be always appropriate. Also, the experimental technique should find applications in measurements of aerosol rate processes that are affected by both particle charge and size (e.g. coagulation, deposition, resuspension), and hence in modeling and simulation of the nuclear source term.

  11. Phase diagram of the CF{sub 4} monolayer and bilayer on graphite

    SciTech Connect (OSTI)

    Thomas, Petros; Hess, George B.

    2014-05-21

    We report an experimental study of physisorbed monolayers and bilayers of CF{sub 4} on graphite using infrared reflection absorption spectroscopy supplemented by ellipsometry. The symmetric CF stretch mode ?{sub 3} near 1283 cm{sup ?1} in the gas is strongly blue shifted in the film by dynamic dipole coupling. This blue shift provides a very sensitive measure of the inter-molecular spacing in the monolayer and, less directly, in the bilayer. We find that important corrections are necessary to the volumetric coverage scales used in previous heat capacity and x-ray diffraction studies of this system. This requires quantitative and some qualitative changes to the previously proposed phase diagram. We find evidence for a new phase transition in the middle of the hexagonal incommensurate region and construct new phase diagrams in both the variables coverage-temperature and chemical potential-temperature. We determine the compressibility and thermal expansion in the low-pressure hexagonal incommensurate phase and values for the entropy change in several phase transitions. Below about 55 K there is evidence of solution of up to 7% of an impurity, most likely CO, in our monolayer but not the bilayer film.

  12. In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial

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

    Photosynthesis | Stanford Synchrotron Radiation Lightsource In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial Photosynthesis Monday, June 30, 2014 Plants and other organisms use a process called photosynthesis to produce carbohydrates and oxygen from water and carbon dioxide using sunlight. Artificial photosynthesis replicates this process to produce energy in the form of usable fuels for human needs. Researches have been developing devices for artificial photosynthesis,

  13. Suitability of Silica Gel to Process INEEL Sodium Bearing Waste - Letter Report

    SciTech Connect (OSTI)

    Kirkham, Robert John; Herbst, Alan Keith

    2000-09-01

    The suitability of using the silica gel process for Idaho National Engineering and Environmental Laboratory (INEEL) sodium bearing waste was investigated during fiscal year 2000. The study was co-funded by the Tanks Focus Area as part of TTP No. ID-77WT-31 and the High Level Waste Program. The task also included the investigation of possible other absorbents. Scoping tests and examination of past work showed that the silica gel absorption/adsorption and drying method was the most promising; thus only silica gel was studied and not other absorbents. The documentation on the Russian silica gel process provided much of the needed information but did not provide some of the processing detail so these facts had to be inferred or gleaned from the literature.

  14. Suitability of epitaxial GaAs for x-ray imaging

    SciTech Connect (OSTI)

    Sun, G.C.; Talbi, N.; Verdeil, C.; Bourgoin, J.C.

    2004-09-20

    Because the rate of indirect photon-electron conversion for scintillator materials coupled with arrays of photodiodes is at least 25 times smaller than the rate of direct conversion, we examine the conditions to be fulfilled by semiconductors undergoing such direct conversion to be applied to x-ray imaging. Bulk grown materials are not well suited to this application, because large defect concentrations give rise to strongly nonuniform electronic properties. We argue that only epitaxial layers are suitable for use as imaging devices and we illustrate our argument using the case of thick epitaxial GaAs layers. Detectors made with such layers exhibit a good energy resolution, a charge collection efficiency which approaches 1, linearity over more than three orders of amplitude, no afterglow (a response time shorter than 20 {mu}s), and no charge-induced polarization effects.

  15. Application Of An Artificial Neural Network Model To A Na-K Geothermom...

    Open Energy Info (EERE)

    for the artificial neural network. Reservoir temperatures of some geothermal fields in Turkey determined by this method are in accord with those determined from other methods....

  16. Development of a Scanning Microscale Fast Neutron Irradiation Platform for Examining the Correlation Between Local Neutron Damage and Graphite Microstructure

    SciTech Connect (OSTI)

    Pinhero, Patrick; Windes, William

    2015-03-10

    The fast particle radiation damage effect of graphite, a main material in current and future nuclear reactors, has significant influence on the utilization of this material in fission and fusion plants. Atoms on graphite crystals can be easily replaced or dislocated by fast protons and result in interstitials and vacancies. The currently accepted model indicates that after most of the interstitials recombine with vacancies, surviving interstitials form clusters and furthermore gather to create loops with each other between layers. Meanwhile, surviving vacancies and interstitials form dislocation loops on the layers. The growth of these inserted layers cause the dimensional increase, i.e. swelling, of graphite. Interstitial and vacancy dislocation loops have been reported and they can easily been observed by electron microscope. However, observation of the intermediate atom clusters becomes is paramount in helping prove this model. We utilize fast protons generated from the University of Missouri Research Reactor (MURR) cyclotron to irradiate highly- oriented pyrolytic graphite (HOPG) as target for this research. Post-irradiation examination (PIE) of dosed targets with high-resolution transmission electron microscopy (HRTEM) has permit observation and analysis of clusters and dislocation loops to support the proposed theory. Another part of the research is to validate M.I. Heggie’s Ruck and Tuck model, which introduced graphite layers may fold under fast particle irradiation. Again, we employed microscopy to image irradiated specimens to determine how the extent of Ruck and Tuck by calculating the number of folds as a function of dose. Our most significant accomplishment is the invention of a novel class of high-intensity pure beta-emitters for long-term lightweight batteries. We have filed four invention disclosure records based on the research conducted in this project. These batteries are lightweight because they consist of carbon and tritium and can be fabricated to conform to many geometric shapes. In addition, we have published eight peer-reviewed American Nuclear Society (ANS) transactions, and presented our findings at ANS National Meetings, and several universities.

  17. Deployment of Smart 3D Subsurface Contaminant Characterization at the Brookhaven Graphite Research Reactor

    SciTech Connect (OSTI)

    Sullivan, T.; Heiser, J.; Kalb, P.; Milian, L.; Newson, C.; Lilimpakas, M.; Daniels, T.

    2002-02-26

    The Brookhaven Graphite Research Reactor (BGRR) Historical Site Assessment (BNL 1999) identified contamination inside the Below Grade Ducts (BGD) resulting from the deposition of fission and activation products from the pile on the inner carbon steel liner during reactor operations. Due to partial flooding of the BGD since shutdown, some of this contamination may have leaked out of the ducts into the surrounding soils. The baseline remediation plan for cleanup of contaminated soils beneath the BGD involves complete removal of the ducts, followed by surveying the underlying and surrounding soils, then removing soil that has been contaminated above cleanup goals. Alternatively, if soil contamination around and beneath the BGD is either non-existent/minimal (below cleanup goals) or is very localized and can be ''surgically removed'' at a reasonable cost, the BGD can be decontaminated and left in place. The focus of this Department of Energy Accelerated Site Technology Deployment (DOE ASTD) project was to determine the extent (location, type, and level) of soil contamination surrounding the BGD and to present this data to the stakeholders as part of the Engineering Evaluation/Cost Analysis (EE/CA) process. A suite of innovative characterization tools was used to complete the characterization of the soil surrounding the BGD in a cost-effective and timely fashion and in a manner acceptable to the stakeholders. The tools consisted of a tracer gas leak detection system that was used to define the gaseous leak paths out of the BGD and guide soil characterization studies, a small-footprint Geoprobe to reach areas surrounding the BGD that were difficult to access, two novel, field-deployed, radiological analysis systems (ISOCS and BetaScint) and a three-dimensional (3D) visualization system to facilitate data analysis/interpretation. All of the technologies performed as well or better than expected and the characterization could not have been completed in the same time or at the same cost without implementing this approach.

  18. Sizes, graphitic structures and fractal geometry of light-duty diesel engine particulates.

    SciTech Connect (OSTI)

    Lee, K. O.; Zhu, J.; Ciatti, S.; Choi, M. Y.; Energy Systems; Drexel Univ.

    2003-01-01

    The particulate matter of a light-duty diesel engine was characterized in its morphology, sizes, internal microstructures, and fractal geometry. A thermophoretic sampling system was employed to collect particulates directly from the exhaust manifold of a 1.7-liter turbocharged common-rail direct-injection diesel engine. The particulate samples collected at various engine-operating conditions were then analyzed by using a high-resolution transmission electron microscope (TEM) and an image processing/data acquisition system. Results showed that mean primary particle diameters (dp), and radii of gyration (Rg), ranged from 19.4 nm to 32.5 nm and 77.4 nm to 134.1 nm, respectively, through the entire engine-operating conditions of 675 rpm (idling) to 4000 rpm and 0% to 100% loads. It was also revealed that the other important parameters sensitive to the particulate formation, such as exhaust-gas recirculation (EGR) rate, equivalence ratio, and temperature, affected particle sizes significantly. Bigger primary particles were measured at higher EGR rates, higher equivalence ratios (fuel-rich), and lower exhaust temperatures. Fractal dimensions (D{sup f}) were measured at a range of 1.5 - 1.7, which are smaller than those measured for heavy-duty direct-injection diesel engine particulates in our previous study. This finding implies that the light-duty diesel engine used in this study produces more stretched chain-like shape particles, while the heavy-duty diesel engine emits more spherical particles. The microstructures of diesel particulates were observed at high TEM magnifications and further analyzed by a Raman spectroscope. Raman spectra revealed an atomic structure of the particulates produced at high engine loads, which is similar to that of typical graphite.

  19. PDGFBB promotes PDGFR{alpha}-positive cell migration into artificial bone in vivo

    SciTech Connect (OSTI)

    Yoshida, Shigeyuki; Center for Human Metabolomic Systems Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 ; Iwasaki, Ryotaro; Kawana, Hiromasa; Miyauchi, Yoshiteru; Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582; Department of Integrated Bone Metabolism and Immunology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 ; Hoshi, Hiroko; Miyamoto, Hiroya; Mori, Tomoaki; Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 ; Kanagawa, Hiroya; Katsuyama, Eri; Fujie, Atsuhiro; Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 ; Hao, Wu; and others

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer We examined effects of PDGFBB in PDGFR{alpha} positive cell migration in artificial bones. Black-Right-Pointing-Pointer PDGFBB was not expressed in osteoblastic cells but was expressed in peripheral blood cells. Black-Right-Pointing-Pointer PDGFBB promoted PDGFR{alpha} positive cell migration into artificial bones but not osteoblast proliferation. Black-Right-Pointing-Pointer PDGFBB did not inhibit osteoblastogenesis. -- Abstract: Bone defects caused by traumatic bone loss or tumor dissection are now treated with auto- or allo-bone graft, and also occasionally by artificial bone transplantation, particularly in the case of large bone defects. However, artificial bones often exhibit poor affinity to host bones followed by bony union failure. Thus therapies combining artificial bones with growth factors have been sought. Here we report that platelet derived growth factor bb (PDGFBB) promotes a significant increase in migration of PDGF receptor {alpha} (PDGFR{alpha})-positive mesenchymal stem cells/pre-osteoblastic cells into artificial bone in vivo. Growth factors such as transforming growth factor beta (TGF{beta}) and hepatocyte growth factor (HGF) reportedly inhibit osteoblast differentiation; however, PDGFBB did not exhibit such inhibitory effects and in fact stimulated osteoblast differentiation in vitro, suggesting that combining artificial bones with PDGFBB treatment could promote host cell migration into artificial bones without inhibiting osteoblastogenesis.

  20. Search for Suitable ICRF Operation Window for the Shaped H-mode Operation of KSTAR

    SciTech Connect (OSTI)

    Park, B. H.; Kim, J. Y.

    2009-11-26

    KSTAR will try to achieve its 1st shaped H-mode plasma in 2010 campaign. The available power is limited by our plan for auxiliary heating system. Up to 2010, NBI with 1 MW, LHCD 0.5 MW, and ECH with 0.5 MW power will be prepared. To accomplish high beta plasma, TF magnetic field will be reduced to 2 T from rated field of 3.5 T. In this case the ECH contribution to H-mode power threshold requirement is ignorant because the 84 GHz frequency does not meet neither fundamental nor second harmonic resonance in the discharge area. Therefore the ICRF heating should carry out important roll to reach power threshold. The ICRF system of tunable frequency from 30 to 60 MHz will come with 1 MW power in 2010. To maximize the ICRF heating efficiency for H-mode purpose, we try to find suitable condition of ICRF heating parameters through the simulation using by TORIC code. Optimizations of RF frequency, toroidal modes controllable by 4 current straps, and the minority concentration are performed. Possibilities of second harmonic heating of minority and the mode converted heating near resonance layer are also studied.

  1. Preparation of powders suitable for conversion to useful .beta.-aluminas

    DOE Patents [OSTI]

    Morgan, Peter E. D.

    1982-01-01

    A process for forming a precursor powder which, when suitably pressed and sintered forms highly pure, densified .beta.- or .beta."-alumina, comprising the steps of: (1) forming a suspension (or slurry) of Bayer-derived Al(OH).sub.3 in a water-miscible solvent; (2) adding an aqueous solution of a Mg compound, a Li compound, a Na compound or mixtures thereof to the Bayer-derived Al(OH).sub.3 suspension while agitating the mixture formed thereby, to produce a gel; (3) drying the gel at a temperature above the normal boiling point of water to produce a powder material; (4) lightly ball milling and sieving said powder material; and (5) heating the ball-milled and sieved powder material at a temperature of between 350.degree. to 900.degree. C. to form the .beta.- or .beta."-alumina precursor powder. The precursor powder, thus formed, may be subsequently isopressed at a high pressure and sintered at an elevated temperature to produce .beta.- or .beta."-alumina. BACKGROUND OF THE INVENTION

  2. Rigorous Screening Technology for Identifying Suitable CO2 Storage Sites II

    SciTech Connect (OSTI)

    George J. Koperna Jr.; Vello A. Kuuskraa; David E. Riestenberg; Aiysha Sultana; Tyler Van Leeuwen

    2009-06-01

    This report serves as the final technical report and users manual for the 'Rigorous Screening Technology for Identifying Suitable CO2 Storage Sites II SBIR project. Advanced Resources International has developed a screening tool by which users can technically screen, assess the storage capacity and quantify the costs of CO2 storage in four types of CO2 storage reservoirs. These include CO2-enhanced oil recovery reservoirs, depleted oil and gas fields (non-enhanced oil recovery candidates), deep coal seems that are amenable to CO2-enhanced methane recovery, and saline reservoirs. The screening function assessed whether the reservoir could likely serve as a safe, long-term CO2 storage reservoir. The storage capacity assessment uses rigorous reservoir simulation models to determine the timing, ultimate storage capacity, and potential for enhanced hydrocarbon recovery. Finally, the economic assessment function determines both the field-level and pipeline (transportation) costs for CO2 sequestration in a given reservoir. The screening tool has been peer reviewed at an Electrical Power Research Institute (EPRI) technical meeting in March 2009. A number of useful observations and recommendations emerged from the Workshop on the costs of CO2 transport and storage that could be readily incorporated into a commercial version of the Screening Tool in a Phase III SBIR.

  3. Lessons Learned from the Application of Bulk Characterization to Individual Containers on the Brookhaven Graphite Research Reactor Decommissioning Project at Brookhaven National Laboratory - 12056

    SciTech Connect (OSTI)

    Kneitel, Terri; Rocco, Diane

    2012-07-01

    When conducting environmental cleanup or decommissioning projects, characterization of the material to be removed is often performed when the material is in-situ. The actual demolition or excavation and removal of the material can result in individual containers that vary significantly from the original bulk characterization profile. This variance, if not detected, can result in individual containers exceeding Department of Transportation regulations or waste disposal site acceptance criteria. Bulk waste characterization processes were performed to initially characterize the Brookhaven Graphite Research Reactor (BGRR) graphite pile and this information was utilized to characterize all of the containers of graphite. When the last waste container was generated containing graphite dust from the bottom of the pile, but no solid graphite blocks, the material contents were significantly different in composition from the bulk waste characterization. This error resulted in exceedance of the disposal site waste acceptance criteria. Brookhaven Science Associates initiated an in-depth investigation to identify the root causes of this failure and to develop appropriate corrective actions. The lessons learned at BNL have applicability to other cleanup and demolition projects which characterize their wastes in bulk or in-situ and then extend that characterization to individual containers. (authors)

  4. Structure of spontaneously formed solid-electrolyte interphase on lithiated graphite determined using small-angle neutron scattering

    SciTech Connect (OSTI)

    Sacci, Robert L [ORNL; Banuelos, Jose Leo [ORNL; Veith, Gabriel M [ORNL; Littrell, Ken [ORNL; Cheng, Yongqiang [ORNL; Wildgruber, Christoph U [ORNL; Jones, Lacy L [ORNL; Ramirez-Cuesta, Anibal J [ORNL; Rother, Gernot [ORNL; Dudney, Nancy J [ORNL

    2015-01-01

    We report the first small-angle neutron scattering of a chemically formed solid-electrolyte interphase from LixC6 reacting with ethylene carbonate/dimethyl carbon solvent. This provides a different and perhaps simpler view of SEI formation than the usual electrochemically-driven reaction. We show that an organic layer coats the graphite particles filling in micro-pores and is polymeric in nature being 1-3 nm thick. We used inelastic neutron scattering to probe the chemistry, and we found that the SEI showed similar inelastic scattering to polyethylene oxide.

  5. Structure of spontaneously formed solid-electrolyte interphase on lithiated graphite determined using small-angle neutron scattering

    SciTech Connect (OSTI)

    Sacci, Robert L.; Banuelos, Jose Leobardo; Veith, Gabriel M.; Littrell, Ken C.; Cheng, Yongqiang Q.; Wildgruber, Christoph U.; Jones, Lacy L.; Ramirez-Cuesta, Anibal J.; Rother, Gernot; Dudney, Nancy J.

    2015-03-25

    We report the first small-angle neutron scattering of a chemically formed solid-electrolyte interphase from LixC6 reacting with ethylene carbonate/dimethyl carbon solvent. This provides a different and perhaps simpler view of SEI formation than the usual electrochemically-driven reaction. We show that an organic layer coats the graphite particles filling in micro-pores and is polymeric in nature being 1-3 nm thick. We used inelastic neutron scattering to probe the chemistry, and we found that the SEI showed similar inelastic scattering to polyethylene oxide.

  6. Structure of Spontaneously Formed Solid-Electrolyte Interphase on Lithiated Graphite Determined Using Small-Angle Neutron Scattering

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

    Sacci, Robert L.; Bañuelos, José Leobardo; Veith, Gabriel M.; Littrell, Ken C.; Cheng, Yongqiang Q.; Wildgruber, Christoph U.; Jones, Lacy L.; Ramirez-Cuesta, Anibal J.; Rother, Gernot; Dudney, Nancy J.

    2015-05-07

    We report the first small-angle neutron scattering of a chemically formed solid-electrolyte interphase from LixC6 reacting with ethylene carbonate/dimethyl carbon solvent. This provides a different and perhaps simpler view of SEI formation than the usual electrochemically-driven reaction. We show that an organic layer coats the graphite particles filling in micro-pores and is polymeric in nature being 1-3 nm thick. We used inelastic neutron scattering to probe the chemistry, and we found that the SEI showed similar inelastic scattering to polyethylene oxide.

  7. Cell-free synthesis system suitable for disulfide-containing proteins

    SciTech Connect (OSTI)

    Matsuda, Takayoshi; Cell-Free Technology Application Laboratory, RIKEN Innovation Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045 ; Watanabe, Satoru; Kigawa, Takanori; Cell-Free Technology Application Laboratory, RIKEN Innovation Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045; Department of Computational Intelligence and Systems Science, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502

    2013-02-08

    Highlights: ? Cell-free synthesis system suitable for disulfide-containing proteins is proposed. ? Disulfide bond formation was facilitated by the use of glutathione buffer. ? DsbC catalyzed the efficient shuffling of incorrectly formed disulfide bonds. ? Milligram quantities of functional {sup 15}N-labeled BPTI and lysozyme C were obtained. ? Synthesized proteins were both catalytically functional and properly folded. -- Abstract: Many important therapeutic targets are secreted proteins with multiple disulfide bonds, such as antibodies, cytokines, hormones, and proteases. The preparation of these proteins for structural and functional analyses using cell-based expression systems still suffers from several issues, such as inefficiency, low yield, and difficulty in stable-isotope labeling. The cell-free (or in vitro) protein synthesis system has become a useful protein production method. The openness of the cell-free system allows direct control of the reaction environment to promote protein folding, making it well suited for the synthesis of disulfide-containing proteins. In this study, we developed the Escherichia coli (E. coli) cell lysate-based cell-free synthesis system for disulfide-containing proteins, which can produce sufficient amounts of functional proteins for NMR analyses. Disulfide bond formation was facilitated by the use of glutathione buffer. In addition, disulfide isomerase, DsbC, catalyzed the efficient shuffling of incorrectly formed disulfide bonds during the protein synthesis reaction. We successfully synthesized milligram quantities of functional {sup 15}N-labeled higher eukaryotic proteins, bovine pancreatic trypsin inhibitor (BPTI) and human lysozyme C (LYZ). The NMR spectra and functional analyses indicated that the synthesized proteins are both catalytically functional and properly folded. Thus, the cell-free system is useful for the synthesis of disulfide-containing proteins for structural and functional analyses.

  8. Testing the suitability of geologic frameworks for extrapolating hydraulic properties across regional scales

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

    Mirus, Benjamin B.; Halford, Keith J.; Sweetkind, Donald; Fenelon, Joseph M.

    2016-02-18

    The suitability of geologic frameworks for extrapolating hydraulic conductivity (K) to length scales commensurate with hydraulic data is difficult to assess. A novel method is presented for evaluating assumed relations between K and geologic interpretations for regional-scale groundwater modeling. The approach relies on simultaneous interpretation of multiple aquifer tests using alternative geologic frameworks of variable complexity, where each framework is incorporated as prior information that assumes homogeneous K within each model unit. This approach is tested at Pahute Mesa within the Nevada National Security Site (USA), where observed drawdowns from eight aquifer tests in complex, highly faulted volcanic rocks providemore » the necessary hydraulic constraints. The investigated volume encompasses 40 mi3 (167 km3) where drawdowns traversed major fault structures and were detected more than 2 mi (3.2 km) from pumping wells. Complexity of the five frameworks assessed ranges from an undifferentiated mass of rock with a single unit to 14 distinct geologic units. Results show that only four geologic units can be justified as hydraulically unique for this location. The approach qualitatively evaluates the consistency of hydraulic property estimates within extents of investigation and effects of geologic frameworks on extrapolation. Distributions of transmissivity are similar within the investigated extents irrespective of the geologic framework. In contrast, the extrapolation of hydraulic properties beyond the volume investigated with interfering aquifer tests is strongly affected by the complexity of a given framework. As a result, testing at Pahute Mesa illustrates how this method can be employed to determine the appropriate level of geologic complexity for large-scale groundwater modeling.« less

  9. Report of early site suitability evaluation of the potential repository site at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

    SciTech Connect (OSTI)

    Younker, J.L.; Andrews, W.B.; Fasano, G.A.; Herrington, C.C.; Mattson, S.R.; Murray, R.C. [Science Applications International Corp., Las Vegas, NV (United States); Ballou, L.B.; Revelli, M.A. [Lawrence Livermore National Lab., CA (United States); Ducharme, A.R.; Shephard, L.E. [Sandia National Labs., Albuquerque, NM (United States); Dudley, W.W.; Hoxie, D.T. [Geological Survey, Denver, CO (United States); Herbst, R.J.; Patera, E.A. [Los Alamos National Lab., NM (United States); Judd, B.R. [Decision Analysis Co., Portola Valley, CA (United States); Docka, J.A.; Rickertsen, L.D. [Weston Technical Associates, Washington, DC (United States)

    1992-01-01

    This study evaluated the technical suitability of Yucca Mountain, Nevada, as a potential site for a mined geologic repository for the permanent disposal of radioactive waste. The evaluation was conducted primarily to determine early in the site characterization program if there are any features or conditions at the site that indicate it is unsuitable for repository development. A secondary purpose was to determine the status of knowledge in the major technical areas that affect the suitability of the site. This early site suitability evaluation (ESSE) was conducted by a team of technical personnel at the request of the Associate Director of the US Department of Energy (DOE) Office of Geologic Disposal, a unit within the DOE`s Office of Civilian Radioactive Waste Management. The Yucca Mountain site has been the subject of such evaluations for over a decade. In 1983, the site was evaluated as part of a screening process to identify potentially acceptable sites. The site was evaluated in greater detail and found suitable for site characterization as part of the Environmental Assessment (EA) (DOE, 1986) required by the Nuclear Waste Policy Act of 1982 (NWPA). Additional site data were compiled during the preparation of the Site Characterization Plan (SCP) (DOE, 1988a). This early site suitability evaluation has considered information that was used in preparing both-documents, along with recent information obtained since the EA and SCP were published. This body of information is referred to in this report as ``current information`` or ``available evidence.``

  10. Interaction of the high energy deuterons with the graphite target in the plasma focus devices based on Lee model

    SciTech Connect (OSTI)

    Akel, M. Alsheikh Salo, S.; Ismael, Sh.; Saw, S. H.; Lee, S.

    2014-07-15

    Numerical experiments are systematically carried out using the Lee model code extended to compute the ion beams on various plasma focus devices operated with Deuterium gas. The deuteron beam properties of the plasma focus are studied for low and high energy plasma focus device. The energy spectral distribution for deuteron ions ejected from the pinch plasma is calculated and the ion numbers with energy around 1 MeV is then determined. The deuteron–graphite target interaction is studied for different conditions. The yield of the reaction {sup 12}C(d,n){sup 13}N and the induced radioactivity for one and multi shots plasma focus devices in the graphite solid target is investigated. Our results present the optimized high energy repetitive plasma focus devices as an alternative to accelerators for the production of {sup 13}N short lived radioisotopes. However, technical challenges await solutions on two fronts: (a) operation of plasma focus machines at high rep rates for a sufficient period of time (b) design of durable targets that can take the thermal load.

  11. Computational Assessment of the GT-MHR Graphite Core Support Structural Integrity in Air-Ingress Accident Condition

    SciTech Connect (OSTI)

    Jong B. Lim; Eung S. Kim; Chang H. Oh; Richard R. Schultz; David A. Petti

    2008-10-01

    The objective of this project was to perform stress analysis for graphite support structures of the General Atomics’ 600 MWth GT-MHR prismatic core design using ABAQUS ® (ver. 6.75) to assess their structural integrity in air-ingress accident conditions where the structure weakens over time due to oxidation damages. The graphite support structures of prismatic type GT-MHR was analyzed based on the change of temperature, burn-off and corrosion depth during the accident period predicted by GAMMA, a multi-dimensional gas multi-component mixture analysis code developed in the Republic of Korea (ROK)/United States (US) International –Nuclear Engineering Research Initiative (I-NERI) project. Both the loading and thermal stresses were analyzed, but the thermal stress was not significant, leaving the loading stress to be the major factor. The mechanical strengths are exceeded between 11 to 11.5 days after loss-of-coolant-accident (LOCA), corresponding to 5.5 to 6 days after the start of natural convection.

  12. Temperature-dependent H{sub 2} gas-sensing properties of fabricated Pd nanowires using highly oriented pyrolytic graphite

    SciTech Connect (OSTI)

    Sennik, Erdem; Kilinc, Necmettin; Oeztuerk, Zafer Ziya

    2010-09-15

    Horizontal palladium (Pd) nanowires and Pd nanoparticles were successfully fabricated directly on highly oriented pyrolytic graphite depending on the electrodeposition time using palladium nitrate [Pd(NO{sub 2}){sub 3}] solution at room temperature, and the temperature-dependent hydrogen (H{sub 2}) sensing properties of these structures were investigated in the concentration range of 50-5000 ppm. Pd nanowires and Pd nanoparticles were fabricated on a graphite surface by applying triple-pulsed potential with varying the electrodeposition time from 400 to 600 s. The fabricated Pd nanowires were characterized by scanning electron microscopy and energy-dispersive x-ray spectroscopy. It was found that the nanowire arrays were continuous, parallel to each other and ordered after an electrodeposition time of 600 s. The diameters of the Pd nanowires and Pd nanoparticles are observed in the range of 70-180 nm. The H{sub 2} sensing properties of these structures were determined with variation in resistance measurements. It was observed that the limit of detection is lower than 50 ppm H{sub 2}, the sensor response was approximately 2% for 1000 ppm H{sub 2} at room temperature, and the sensor response was decreased with increasing temperature.

  13. Surface daytime net radiation estimation using artificial neural networks

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

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; Zhang, Xiaotong; Xiao, Zhiqiang

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010more » both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.« less

  14. In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial...

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

    In-situ X-ray Photoelectron Spectroscopy of a Catalyst for Artificial Photosynthesis Monday, June 30, 2014 Plants and other organisms use a process called photosynthesis to produce...

  15. Artificial Lift Systems Market is expected to reach USD 19,806...

    Open Energy Info (EERE)

    Artificial Lift Systems Market is expected to reach USD 19,806.8 Million by 2020 Home > Groups > Renewable Energy RFPs Wayne31jan's picture Submitted by Wayne31jan(150) Contributor...

  16. New Artificial Cells Mimic Nature's Tiny Reactors | U.S. DOE Office of

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

    Science (SC) New Artificial Cells Mimic Nature's Tiny Reactors Basic Energy Sciences (BES) BES Home About Research Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC) Community Resources Contact Information Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3081 F: (301) 903-6594 E: Email Us More Information » 09.01.15 New Artificial Cells

  17. Rational Design of Artificial Metal-Based Enzymes | Center for Bio-Inspired

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

    Solar Fuel Production Rational Design of Artificial Metal-Based Enzymes 17 Mar 2014 Giovanna Ghirlanda is one of the EFRC Principal Investigators. She is an Associate Professor at the Department of Chemistry and Biochemistry, ASU. In the Center she leads a collaborative research of Subtask 3 with an objective to design and optimize artificial catalysts for hydrogen production. "...We are interested in evolving or designing, rationally, of novel proteins that can carry out the specific

  18. Artificial Moth Eyes Enhance Silicon Solar Cells | U.S. DOE Office of

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

    Science (SC) Artificial Moth Eyes Enhance Silicon Solar Cells Basic Energy Sciences (BES) BES Home About Research Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC) Community Resources Contact Information Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3081 F: (301) 903-6594 E: Email Us More Information » 03.31.16 Artificial Moth Eyes

  19. Mimicking Nature - A Step Towards Artificial Photosynthesis| U.S. DOE

    Office of Science (SC) Website

    Office of Science (SC) Mimicking Nature - A Step Towards Artificial Photosynthesis Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights Highlight Archives News & Events Publications History Contact BES Home 05.03.12 Mimicking Nature - A Step Towards Artificial Photosynthesis Print Text Size: A A A FeedbackShare Page Scientific Achievement Built a synthetic light harvesting antenna which mimics those found in photosynthetic bacteria Significance and

  20. Students analyze artificial implants at ASM Materials Camp | Y-12 National

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

    Security Complex Students analyze artificial ... Students analyze artificial implants at ASM Materials Camp Posted: June 10, 2013 - 8:37am Student Hunter Stombaugh loads a material sample into the Saphir 550.3, a laboratory instrument used to grind and polish samples before placing them in an electron microscope for analysis. OAK RIDGE, Tenn. - Fifteen high school students and one college freshman recently got up close and personal with lab equipment worth nearly a half million dollars at

  1. 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

    2009-12-01

    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.

  2. Using FEP's List and a PA Methodology for Evaluating Suitable Areas for the LLW Repository in Italy

    SciTech Connect (OSTI)

    Risoluti, P.; Ciabatti, P.; Mingrone, G.

    2002-02-26

    In Italy following a referendum held in 1987, nuclear energy has been phased out. Since 1998, a general site selection process covering the whole Italian territory has been under way. A GIS (Geographic Information System) methodology was implemented in three steps using the ESRI Arc/Info and Arc/View platforms. The screening identified approximately 0.8% of the Italian territory as suitable for locating the LLW Repository. 200 areas have been identified as suitable for the location of the LLW Repository, using a multiple exclusion criteria procedure (1:500,000), regional scale (1:100.000) and local scale (1:25,000-1:10,000). A methodology for evaluating these areas has been developed allowing, along with the evaluation of the long term efficiency of the engineered barrier system (EBS), the characterization of the selected areas in terms of physical and safety factors and planning factors. The first step was to identify, on a referenced FEPs list, a group of geomorphological, geological, hydrogeological, climatic and human behavior caused process and/or events, which were considered of importance for the site evaluation, taking into account the Italian situation. A site evaluation system was established ascribing weighted scores to each of these processes and events, which were identified as parameters of the new evaluation system. The score of each parameter is ranging from 1 (low suitability) to 3 (high suitability). The corresponding weight is calculated considering the effect of the parameter in terms of total dose to the critical group, using an upgraded AMBER model for PA calculation. At the end of the process an index obtained by a score weighted sum gives the degree of suitability of the selected areas for the LLW Repository location. The application of the methodology to two selected sites is given in the paper.

  3. Products of an Artificially Induced Hydrothermal System at Yucca Mountain

    SciTech Connect (OSTI)

    S. Levy

    2000-08-07

    Studies of mineral deposition in the recent geologic past at Yucca Mountain, Nevada, address competing hypotheses of hydrothermal alteration and deposition from percolating groundwater. The secondary minerals being studied are calcite-opal deposits in fractures and lithophysal cavities of ash-flow tuffs exposed in the Exploratory Studies Facility (ESF), a 7.7-km tunnel excavated by the Yucca Mountain Site Characterization Project within Yucca Mountain. An underground field test in the ESF provided information about the minerals deposited by a short-lived artificial hydrothermal system and an opportunity for comparison of test products with the natural secondary minerals. The heating phase lasted nine months, followed by a nine-month cooling period. Natural pore fluids were the only source of water during the thermal test. Condensation and reflux of water driven away from the heater produced fluid flow in certain fractures and intersecting boreholes. The mineralogic products of the thermal test are calcite-gypsum aggregates of less than 4-micrometer crystals and amorphous silica as glassy scale less than 0.2 mm thick and as mounds of tubules with diameters less than 0.7 micrometers. The minute crystal sizes of calcite and gypsum from the field test are very different from the predominantly coarser calcite crystals (up to cm scale) in natural secondary-mineral deposits at the site. The complex micrometer-scale textures of the amorphous silica differ from the simple forms of opal spherules and coatings in the natural deposits, even though some natural spherules are as small as 1 micrometer. These differences suggest that the natural minerals, especially if they were of hydrothermal origin, may have developed coarser or simpler forms during subsequent episodes of dissolution and redeposition. The presence of gypsum among the test products and its absence from the natural secondary-mineral assemblage may indicate a higher degree of evaporation during the test than during the deposition of natural calcite-opal deposits.

  4. Surface daytime net radiation estimation using artificial neural networks

    SciTech Connect (OSTI)

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; Zhang, Xiaotong; Xiao, Zhiqiang

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010 both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.

  5. Thin graphite bipolar plate with associated gaskets and carbon cloth flow-field for use in an ionomer membrane fuel cell

    DOE Patents [OSTI]

    Marchetti, George A.

    2003-01-03

    The present invention comprises a thin graphite plate with associated gaskets and pieces of carbon cloth that comprise a flow-field. The plate, gaskets and flow-field comprise a "plate and gasket assembly" for use in an ionomer membrane fuel cell, fuel cell stack or battery.

  6. Low-energy D{sup +} and H{sup +} ion irradiation effects on highly oriented pyrolytic graphite

    SciTech Connect (OSTI)

    Kue Park, Jun; Won Lee, Kyu; Hee Han, Jun; Jung Kweon, Jin; Kim, Dowan; Eui Lee, Cheol [Department of Physics and Institute for Nano Science, Korea University, Seoul 136-713 (Korea, Republic of)] [Department of Physics and Institute for Nano Science, Korea University, Seoul 136-713 (Korea, Republic of); Lim, Sun-Taek; Kim, Gon-Ho [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Noh, S. J.; Kim, H. S. [Department of Applied Physics, Dankook University, Yongin 448-701 (Korea, Republic of)] [Department of Applied Physics, Dankook University, Yongin 448-701 (Korea, Republic of)

    2013-12-07

    We have investigated the low-energy (100 eV) D{sup +} and H{sup +} ion irradiation effects on the structural and chemical properties of highly oriented pyrolytic graphite (HOPG). Structural disorder due to the ion irradiation was identified by the Raman spectroscopy, the D{sup +} irradiation giving rise to greater structural disorder than the H{sup +} irradiation. Only sp{sup 2} bonding was identified in the X-ray photoemission spectroscopy of the D{sup +}-irradiated HOPG, indicating no change in the surface chemical structure. The H{sup +} irradiation, on the other hand, gave rise to sp{sup 3} bonding and ???{sup *} transition, the sp{sup 3} bonding increasing with increasing irradiation dose. It is thus shown that the chemical properties of the HOPG surface may be sensitively modified by the low-energy H{sup +} ion irradiation, but not by the low-energy D{sup +} ion irradiation.

  7. Neutron Reference Benchmark Field Specifications: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Environment (ACRR-PLG-CC-32-CL).

    SciTech Connect (OSTI)

    Vega, Richard Manuel; Parm, Edward J.; Griffin, Patrick J.; Vehar, David W.

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity with the Polyethylene-Lead-Graphite (PLG) bucket, reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 37 integral dosimetry measurements in the neutron field are reported.

  8. 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

    2011-01-01

    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.

  9. Recommendation by the Secretary of Energy Regarding the Suitability of the Yucca Mountain Site for a Repository Under the Nuclear Waste Policy Act of 1982

    Broader source: Energy.gov [DOE]

    Recommendation by the Secretary of Energy Regarding the Suitability of the Yucca Mountain Site for a Repository Under the Nuclear Waste Policy Act of 1982

  10. Realizing three-dimensional artificial spin ice by stacking planar nano-arrays

    SciTech Connect (OSTI)

    Chern, Gia-Wei; Reichhardt, Charles; Nisoli, Cristiano

    2014-01-06

    Artificial spin ice is a frustrated magnetic two-dimensional nano-material, recently employed to study variety of tailor-designed unusual collective behaviours. Recently proposed extensions to three dimensions are based on self-assembly techniques and allow little control over geometry and disorder. We present a viable design for the realization of a three-dimensional artificial spin ice with the same level of precision and control allowed by lithographic nano-fabrication of the popular two-dimensional case. Our geometry is based on layering already available two-dimensional artificial spin ice and leads to an arrangement of ice-rule-frustrated units, which is topologically equivalent to that of the tetrahedra in a pyrochlore lattice. Consequently, we show, it exhibits a genuine ice phase and its excitations are, as in natural spin ice materials, magnetic monopoles interacting via Coulomb law.

  11. Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    DOE Patents [OSTI]

    Ray, S.P.; Rapp, R.A.

    1986-04-22

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

  12. Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    DOE Patents [OSTI]

    Ray, Siba P. (Pittsburgh, PA); Rapp, Robert A. (Columbus, OH)

    1986-01-01

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily.

  13. High efficiency, high quality x-ray optic based on ellipsoidally bent highly oriented pyrolytic graphite crystal for ultrafast x-ray diffraction experiments

    SciTech Connect (OSTI)

    Uschmann, I.; Nothelle, U.; Foerster, E.; Arkadiev, V.; Langhoff, N.; Antonov, A.; Grigorieva, I.; Steinkopf, R.; Gebhardt, A

    2005-08-20

    By the use of a thin highly oriented pyrolytic graphite crystal (HOPG) bent to a high-performance ellipsoidal shape it was possible to focus monochromatic x-rays of 4.5 keV photon energy with an efficiency of 0.0033, which is 30 times larger than for previously used bent crystals. Isotropic TiK{sub a}lpha radiation of a 150 {mu}m source was focused onto a 450 {mu}m spot. The size of the focal spot can be explained by broadening due to the mosaic crystal rocking curve. The rocking curve width (FWHM) of the thin graphite foil was determined to 0.11 deg. . The estimated temporal broadening of an ultrashort Kalpha pulse by the crystal is not larger than 300 fs. These properties make the x-ray optic very attractive for ultrafast time-resolved x-ray measurements.

  14. DOE-Funded Researchers Honored by R&D Magazine: Leader of DOE Artificial

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

    Researchers Honored by R&D Magazine DOE-Funded Researchers Honored by R&D Magazine October 20, 2005 - 12:23pm Addthis Leader of the DOE Artificial Retina Project Named "Innovator of the Year;" Scientists and Engineers at 12 DOE Labs Win 29 R&D 100 Awards for 2005 WASHINGTON, DC-Secretary of Energy Samuel W. Bodman today congratulated the leader of the Department of Energy's Artificial Retina Project, who has been honored as R&D Magazine's "Innovator of the

  15. Effects of exchange bias on magnetotransport in permalloy kagome artificial spin ice

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

    Le, B. L.; Rench, D. W.; Misra, R.; O’Brien, L.; Leighton, C.; Samarth, N.; Schiffer, P.

    2015-02-01

    We investigate the magnetotransport properties of connected kagome artificial spin ice networks composed of permalloy nanowires. Our data show clear evidence of magnetic switching among the wires, both in the longitudinal and transverse magnetoresistance. An unusual asymmetry with field sweep direction appears at temperatures below about 20 K that appears to be associated with exchange bias resulting from surface oxidation of permalloy, and which disappears in alumina-capped samples. These results demonstrate that exchange bias is a phenomenon that must be considered in understanding the physics of such artificial spin ice systems, and that opens up new possibilities for their control.

  16. Energy Distributions of Neutrons Scattered from Graphite, Light and Heavy Water, Ice, Zirconium Hydride, Lithium Hydride, Sodium Hydride and Ammonium Chloride by the Beryllium Detector Method

    DOE R&D Accomplishments [OSTI]

    Woods, A. D. B.; Brockhouse, Bertram N.; Sakamoto, M.; Sinclair, R. N.

    1960-09-12

    Energy distributions of neutrons scattered from various moderators and from several hydrogenous substances were measured at energy transfers of 0.02 to 0.24 ev. Results from experiments on graphite, light and heavy water, ice, ZrH, LiH, NaH, and NH4Cl are included. It is noted that the results are of a preliminary character; however, they are probably the most accurate measurements of high-energy transfers yet made. (J.R.D.)

  17. A New Direct-Pour In-Mold (DPI) Technology for Producing Ductile and Compacted Graphite Iron Castings.

    SciTech Connect (OSTI)

    Jason Hitchings; Jay R. Hitchings

    2007-07-20

    A new "Direct Pour In-Mold" (DPI) Magnesium treatment technology has been developed that can produce both Nodular and Compacted Graphite iron. The DPI technology converts the standard horizontal runner system into a vertical one, by placing a Magnesium Ferrosilicon treatment alloy and molten metal filter into a specially designed container. The DPI container is easily placed into either vertically or horizontally parted molds, and then a base metal can be poured directly into it. The metal is treated and filtered as it passes through, and then proceeds directly into a runner or casting cavity. Various sizes of containers provide all of the necessary components required to deliver a range of weights of treated and filtered metal at accurate and consistent flow rates. The DPI containers provide energy savings over competing techniques, increased mold yields, very high Magnesium recovery, zero Magnesium fume, and no post inoculation is required. By treating the metal just prior to it entering a casting cavity many other benefits and advantages are also realized.

  18. Experimental Plan for EDF Energy Creep Rabbit Graphite Irradiations- Rev. 2 (replaces Rev. 0 ORNL/TM/2013/49).

    SciTech Connect (OSTI)

    Burchell, Timothy D

    2014-07-01

    The experimental results obtained here will assist in the development and validation of future models of irradiation induced creep of graphite by providing the following data: Inert creep stain data from low to lifetime AGR fluence Inert creep-property data (especially CTE) from low to lifetime AGR fluence Effect of oxidation on creep modulus (by indirect comparison with experiment 1 and direct comparison with experiment 3 NB. Experiment 1 and 3 are not covered here) Data to develop a mechanistic understanding, including oAppropriate creep modulus (including pinning and high dose effects on structure) oInvestigation of CTE-creep strain behavior under inert conditions oInformation on the effect of applied stress/creep strain on crystallite orientation (requires XRD) oEffect of creep strain on micro-porosity (requires tomography & microscopy) This document describes the experimental work planned to meet the requirements of project technical specification [1] and EDF Energy requests for additional Pre-IE work. The PIE work is described in detail in this revision (Section 8 and 9).

  19. First results of a polychromatic artificial sodium star for the correction of tilt

    SciTech Connect (OSTI)

    Friedman, H.; Foy, R..; Tallon, M.; Migus, A.

    1996-03-06

    This paper presents the first results of a joint experiment carried out at Lawrence Livermore National Laboratory during January, 1996. Laser and optical systems were tested to provide a polychromatic artificial sodium star for the correction of tilt. This paper presents the results of that experiment.

  20. Effects of lithium salt concentration on graphited carbon microbead anodes in the piperidinium-based hybrid electrolytes

    SciTech Connect (OSTI)

    Gao, Kun; Li, Shu-Dan

    2015-01-15

    Graphical abstract: “Lithium aggregates” usually cause a significant decrease in Li{sup +} mobility and transfer efficiency. Therefore, as important as the problem of SEI, the content of lithium salt and the interaction between Li{sup +} and ILs’ anions should be taken into consideration in the optimization of ILs-based electrolytes for Li-ion batteries. - Highlights: • “Lithium aggregates” in piperidinium-based electrolytes are evidenced by IR and NMR. • High LiPF{sub 6} content could decrease Li{sup +} mobility due to “ionic aggregates”. • Lithium salt concentration is an important factor affecting graphite performances. - Abstract: The variations in LiPF{sub 6} concentration lead to the very different electrochemical performances of carbon microbeads anodes in the piperidinium-based hybrid electrolytes. The “two peaks” behaviors of lithium plating observed in cyclic voltammetry tests, and some detailed changes in infrared spectra and nuclear magnetic resonance indicates that the formation of “ionic aggregates” related to lithium ions”. Therefore, the excessive lithium salts in the piperidinium-based hybrid electrolytes, usually cause a significant decrease in Li{sup +} mobility and transfer efficiency. The main behaviors are that, when LiPF{sub 6} concentrations increased from 0.2 to 1.2 mol kg{sup −1}, the apparent migration energies (E{sub a}) increase largely from 8.83 to 21.16 kJ mol{sup −1}, while the lithium transference numbers (t{sub Li{sup +}}) drop markedly from 0.538 to 0.292.

  1. 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

    2014-11-14

    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.

  2. From Artificial Atoms to Nanocrystal Molecules: Preparation and Properties of More Complex Nanostructures

    SciTech Connect (OSTI)

    Choi, Charina L; Alivisatos, A Paul

    2009-10-20

    Quantum dots, which have found widespread use in fields such as biomedicine, photovoltaics, and electronics, are often called artificial atoms due to their size-dependent physical properties. Here this analogy is extended to consider artificial nanocrystal molecules, formed from well-defined groupings of plasmonically or electronically coupled single nanocrystals. Just as a hydrogen molecule has properties distinct from two uncoupled hydrogen atoms, a key feature of nanocrystal molecules is that they exhibit properties altered from those of the component nanoparticles due to coupling. The nature of the coupling between nanocrystal atoms and its response to vibrations and deformations of the nanocrystal molecule bonds are of particular interest. We discuss synthetic approaches, predicted and observed physical properties, and prospects and challenges toward this new class of materials.

  3. PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE BROOKHAVEN GRAPHITE RESEARCH REACTOR ENGINEERED CAP, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK DCN 5098-SR-07-0

    SciTech Connect (OSTI)

    Evan Harpenau

    2011-07-15

    The Oak Ridge Institute for Science and Education (ORISE) has reviewed the project documentation and data for the Brookhaven Graphite Research Reactor (BGRR) Engineered Cap at Brookhaven National Laboratory (BNL) in Upton, New York. The Brookhaven Science Associates (BSA) have completed removal of affected soils and performed as-left surveys by BSA associated with the BGRR Engineered Cap. Sample results have been submitted, as required, to demonstrate that remediation efforts comply with the cleanup goal of {approx}15 mrem/yr above background to a resident in 50 years (BNL 2011a).

  4. Method and apparatus for optimizing operation of a power generating plant using artificial intelligence techniques

    DOE Patents [OSTI]

    Wroblewski, David; Katrompas, Alexander M.; Parikh, Neel J.

    2009-09-01

    A method and apparatus for optimizing the operation of a power generating plant using artificial intelligence techniques. One or more decisions D are determined for at least one consecutive time increment, where at least one of the decisions D is associated with a discrete variable for the operation of a power plant device in the power generating plant. In an illustrated embodiment, the power plant device is a soot cleaning device associated with a boiler.

  5. "Artificial" brains, electrical grids, and disease modeling: Los Alamos

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

    science discoveries unveiled September 15 Science discoveries unveiled "Artificial" brains, electrical grids, and disease modeling: Los Alamos science discoveries unveiled September 15 The event is an opportunity for business leaders and community members to learn about where science is heading, as well as for students to discover potential new career directions. September 8, 2009 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez

  6. Magnetic vortex crystal formation in the antidot complement of square artificial spin ice

    SciTech Connect (OSTI)

    Araujo, C. I. L. de Silva, R. C.; Ribeiro, I. R. B.; Nascimento, F. S.; Felix, J. F.; Ferreira, S. O.; Moura-Melo, W. A.; Pereira, A. R.; Ml, L. A. S.

    2014-03-03

    We have studied ferromagnetic nickel thin films patterned with square lattices of elongated antidots that are negative analogues of square artificial spin ice. Micromagnetic simulations and direct current magnetic moment measurements reveal in-plane anisotropy of the magnetic hysteresis loops, and the formation of a dense array of magnetic vortices with random polarization and chirality. These multiply-connected antidot arrays could be superior to lattices of disconnected nanodisks for investigations of vortex switching by applied electric current.

  7. De novo Design of an Artificial bis-[4Fe4S] Binding Protein

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

    Electricity & Fuel » Lighting » Daylighting Daylighting Daylighting-the use of windows or skylights for natural lighting and temperature regulation-is one building strategy that can save money for homeowners and businesses. Daylighting is the use of windows and skylights to bring sunlight into your home. Today's highly energy-efficient windows, as well as advances in lighting design, reduce the need for artificial lighting during daylight hours without causing heating or cooling problems.

  8. Temperature and magnetic-field driven dynamics in artificial magnetic square ice

    SciTech Connect (OSTI)

    Sophie A. Morley; Stein, Aaron; Rosamond, Mark C.; Venero, Diego Alba; Hrabec, Ales; Shepley, Philippa M.; Im, Mi -Young; Fischer, Peter; Bryan, Matthew T.; Allwood, Dan A.; Steadman, Paul; Langridge, Sean; Marrows, Christopher H.

    2015-08-09

    Artificial spin ices are often spoken of as being realisations of some of the celebrated vertex models of statistical mechanics, where the exact microstate of the system can be imaged using advanced magnetic microscopy methods. The fact that a stable image can be formed means that the system is in fact athermal and not undergoing the usual finite-temperature fluctuations of a statistical mechanical system. In this paper we report on the preparation of artificial spin ices with islands that are thermally fluctuating due to their very small size. The relaxation rate of these islands was determined using variable frequency focused magneto-optic Kerr measurements. We performed magnetic imaging of artificial spin ice under varied temperature and magnetic field using X-ray transmission microscopy which uses X-ray magnetic circular dichroism to generate magnetic contrast. Furthermore, we have developed an on-membrane heater in order to apply temperatures in excess of 700 K and have shown increased dynamics due to higher temperature. Due to the ‘photon-in, photon-out' method employed here, it is the first report where it is possible to image the microstates of an ASI system under the simultaneous application of temperature and magnetic field, enabling the determination of relaxation rates, coercivties, and the analysis of vertex population during reversal.

  9. Temperature and magnetic-field driven dynamics in artificial magnetic square ice

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

    Sophie A. Morley; Stein, Aaron; Rosamond, Mark C.; Venero, Diego Alba; Hrabec, Ales; Shepley, Philippa M.; Im, Mi -Young; Fischer, Peter; Bryan, Matthew T.; Allwood, Dan A.; et al

    2015-08-09

    Artificial spin ices are often spoken of as being realisations of some of the celebrated vertex models of statistical mechanics, where the exact microstate of the system can be imaged using advanced magnetic microscopy methods. The fact that a stable image can be formed means that the system is in fact athermal and not undergoing the usual finite-temperature fluctuations of a statistical mechanical system. In this paper we report on the preparation of artificial spin ices with islands that are thermally fluctuating due to their very small size. The relaxation rate of these islands was determined using variable frequency focusedmore » magneto-optic Kerr measurements. We performed magnetic imaging of artificial spin ice under varied temperature and magnetic field using X-ray transmission microscopy which uses X-ray magnetic circular dichroism to generate magnetic contrast. Furthermore, we have developed an on-membrane heater in order to apply temperatures in excess of 700 K and have shown increased dynamics due to higher temperature. Due to the ‘photon-in, photon-out' method employed here, it is the first report where it is possible to image the microstates of an ASI system under the simultaneous application of temperature and magnetic field, enabling the determination of relaxation rates, coercivties, and the analysis of vertex population during reversal.« less

  10. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

    SciTech Connect (OSTI)

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GA down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.

  11. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

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

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GAmore » down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.« less

  12. GRAPHITE IMPREGNATION METHOD

    DOE Patents [OSTI]

    Kertesz, F.; Buttram, H.J.

    1962-04-24

    ABS>A method for impregnating a refractory material by filling its pores with a first salt having a high melting temperature is described. The salt is mixed with another, more volatile salt, giving the mixture a much lower melting temperature than that of the first salt. The material is coated with the mixture, then heated to drive off the volatile salt, leaving the first salt in place. (AEC)

  13. Protection of the female reproductive system from natural and artificial insults

    DOE Patents [OSTI]

    Tilly, Jonathan L.; Kolesnick, Richard N.

    2010-12-14

    Described are methods for protecting the female reproductive system against natural and artificial insults by administering to women a composition comprising an agent that antagonizes one or more acid sphingomyelinase (ASMase) gene products. Specifically, methods disclosed herein serve to protect women's germline from damage resulting from cancer therapy regimens including chemotherapy or radiotherapy. In one aspect, the method preserves, enhances, or revives ovarian function in women, by administering to women a composition containing sphingosine-1-phosphate, or an analog thereof. Also disclosed are methods to prevent or ameliorate menopausal syndromes and to improve in vitro fertilization techniques.

  14. Pulse imaging and nonadiabatic control of solid-state artificial atoms

    SciTech Connect (OSTI)

    Bylander, Jonas; Rudner, Mark S.; Shytov, Andrey V.; Valenzuela, Sergio O.; Berns, David M.; Berggren, Karl K.; Levitov, Leonid S.; Oliver, William D.

    2009-12-01

    Transitions in an artificial atom, driven nonadiabatically through an energy-level avoided crossing, can be controlled by carefully engineering the driving protocol. We have driven a superconducting persistent-current qubit with a large-amplitude radio-frequency field. By applying a biharmonic wave form generated by a digital source, we demonstrate a mapping between the amplitude and phase of the harmonics produced at the source and those received by the device. This allows us to image the actual wave form at the device. This information is used to engineer a desired time dependence, as confirmed by the detailed comparison with a simulation.

  15. Method for improving product yields in an anionic metalloporphyrin-based artificial photosynthesis system

    DOE Patents [OSTI]

    Shelnutt, John A.

    1986-01-01

    A method for improving product yields in an anionic metalloporphyrin-based artificial photosynthesis system for hydrogen generation which comprises forming an aqueous solution comprising an electron donor, methylviologen, and certain metalloporphyrins and metallochlorins, and irradiating said aqueous solution with light in the presence of a catalyst. In the photosynthesis process, solar energy is collected and stored in the form of a gas hydrogen. Ligands attached above and below the metalloporphyrin and metallochlorin plane are capable of sterically blocking photochemically inactive electrostatically bound .pi.--.pi. complexes which can develop.

  16. Method for improving product yields in an anionic metalloporphyrin-based artificial photosynthesis system

    DOE Patents [OSTI]

    Shelnutt, J.A.

    1984-11-29

    A method is disclosed improving product yields in an anionic metalloporphyrin-based artificial photosynthesis system for hydrogen generation. The method comprises forming an aqueous solution comprising an electron donor, methylviologen, and certain metalloporphyrins and metallochlorins, and irradiating said aqueous solution with light in the presence of a catalyst. In the photosynthesis process, solar energy is collected and stored in the form of a hydrogen. Ligands attached above and below the metalloporphyrin and metallochlorin plane are capable of sterically blocking photochemically inactive electrostatically bound ..pi..-..pi.. complexes which can develop.

  17. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    SciTech Connect (OSTI)

    Susmikanti, Mike; Sulistyo, Jos

    2014-09-30

    Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to develop code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix.

  18. Realizing InGaN monolithic solar-photoelectrochemical cells for artificial photosynthesis

    SciTech Connect (OSTI)

    Dahal, R.; Pantha, B. N.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2014-04-07

    InGaN alloys are very promising for solar water splitting because they have direct bandgaps that cover almost the whole solar spectrum. The demonstration of direct solar-to-fuel conversion without external bias with the sunlight being the only energy input would pave the way for realizing photoelectrochemical (PEC) production of hydrogen by using InGaN. A monolithic solar-PEC cell based on InGaN/GaN multiple quantum wells capable to directly generate hydrogen gas under zero bias via solar water splitting is reported. Under the irradiation by a simulated sunlight (1-sun with 100 mW/cm{sup 2}), a 1.5% solar-to-fuel conversion efficiency has been achieved under zero bias, setting a fresh benchmark of employing III-nitrides for artificial photosynthesis. Time dependent hydrogen gas production photocurrent measured over a prolonged period (measured for 7 days) revealed an excellent chemical stability of InGaN in aqueous solution of hydrobromic acid. The results provide insights into the architecture design of using InGaN for artificial photosynthesis to provide usable clean fuel (hydrogen gas) with the sunlight being the only energy input.

  19. Comparative toxicity of pentachlorophenol to three earthworm species in artificial soil

    SciTech Connect (OSTI)

    Fitzgerald, D.; Lanno, R.P.; Farwell, A.; Dixon, D.G.

    1994-12-31

    Although methods for standardized toxicity tests with earthworms exist, many of the test parameters and conditions have not been validated in actual tests and with different species of worms. This study evaluated the toxicity of pentachlorophenol (PCP) to three species of earthworms, Lumbricus terrestris, Eisenia fetida, and Eudrilus eugeniae using various methods of data analysis and body residues. Tests were conducted in artificial soil for a period of 28 days or until an Acute Lethality Threshold (ALT) was reached. An intensive temporal sampling regime was applied to generate sufficient data for the accurate estimation of ALTs using both LC50/time and time-to-death/soil concentration methods of data analysis. L. terrestris was tested at 15 C, E. eugeniae at 24 C, and E. fetida at both temperatures. Total body residues of PCP were measured by GC following cryogenic separation of the lipid fraction of the worm. ALTs were significantly different between E. fetida and the two larger species of worms. No effect of temperature on the ALT for E. fetida was observed, although the time taken to reach the ALT increased at the lower temperature. The relationship of PCP residues at mortality will be discussed in terms of the effects of species, body size and temperature. Limitations of the artificial soil based upon growth curves of worms will also be examined.

  20. Snag characteristics and dynamics following natural and artificially induced mortality in a managed loblolly pine forest.

    SciTech Connect (OSTI)

    Zarnoch, Stanley J.; Vukovich, Mark A.; Kilgo, John C.; Blake, John I.

    2013-06-10

    A 14-year study of snag characteristics was established in 41- to 44-year old loblolly pine (Pinus taeda L.) stands in southeastern USA. During the initial 5.5 years, no stand manipulation or unusually high-mortality events occurred. Afterwards, three treatments were applied consisting of trees thinned and removed, trees felled and not removed, and artificial creation of snags produced by girdling and herbicide injection. The thinned treatments were designed to maintain the same live canopy density as the snag-created treatment, disregarding snags that remained standing.We monitored snag height, diameter, density, volume, and bark percentage; the number of cavities was monitored in natural snags only. During the first 5.5 years, recruitment and loss rates were stable, resulting in a stable snag population. Large snags (?25 cm diameter) were common, but subcanopy small snags (10 to <25 cm diameter) dominated numerically. Large natural snags survived (90% quantile) significantly longer (6.09.4 years) than smaller snags (4.46.9 years). Large artificial snags persisted the longest (11.8 years). Cavities in natural snags developed within 3 years following tree death. The mean number of cavities per snag was five times greater in large versus small snags and large snags were more likely to have multiple cavities, emphasizing the importance of mature pine stands for cavity-dependent wildlife species.

  1. Molecular orientation of copper phthalocyanine thin films on different monolayers of fullerene on SiO{sub 2} or highly oriented pyrolytic graphite

    SciTech Connect (OSTI)

    Wang, Chenggong; Wang, Congcong; Liu, Xiaoliang; Xu, Xumei; Li, Youzhen; Xie, Fangyan; Gao, Yongli

    2015-03-23

    The interface electronic structures of copper phthalocyanine (CuPc) have been studied using ultraviolet photoemission spectroscopy as different monolayers of C{sub 60} were inserted between CuPc and a SiO{sub 2} or highly ordered pyrolytic graphite (HOPG) substrate. The results show that CuPc has standing up configuration with one monolayer of C{sub 60} insertion on SiO{sub 2} while lying down on HOPG, indicating that the insertion layer propagates the CuPc-substrate interaction. Meanwhile, CuPc on more than one monolayers of C{sub 60} on different substrates show that the substrate orientation effect quickly vanished. Our study elucidates intriguing molecular interactions that manipulate molecular orientation and donor-acceptor energy level alignment.

  2. A framework for developing a mimetic tensor artificial viscosity for Lagrangian hydrocodes on arbitrary polygonal and polyhedral meshes (u)

    SciTech Connect (OSTI)

    Lipnikov, Konstantin; Shashkov, Mikhail

    2011-01-11

    We construct a new mimetic tensor artificial viscosity on general polygonal and polyhedral meshes. The tensor artificial viscosity is based on a mimetic discretization of coordinate invariant operators, divergence of a tensor and gradient of a vector. The focus of this paper is on the symmetric form, div ({mu},{var_epsilon}(u)), of the tensor artificial viscosity where {var_epsilon}(u) is the symmetrized gradient of u and {mu}, is a tensor. The mimetic discretizations of this operator is derived for the case of a full tensor coefficient {mu}, that may reflect a shock direction. We demonstrate performance of the new viscosity for the Noh implosion, Sedov explosion and Saltzman piston problems in both Cartesian and axisymmetric coordinate systems.

  3. Robustness of fractional quantum Hall states with dipolar atoms in artificial gauge fields

    SciTech Connect (OSTI)

    Grass, T.; Baranov, M. A.; Lewenstein, M.

    2011-10-15

    The robustness of fractional quantum Hall states is measured as the energy gap separating the Laughlin ground state from excitations. Using thermodynamic approximations for the correlation functions of the Laughlin state and the quasihole state, we evaluate the gap in a two-dimensional system of dipolar atoms exposed to an artificial gauge field. For Abelian fields, our results agree well with the results of exact diagonalization for small systems but indicate that the large value of the gap predicted [Phys. Rev. Lett. 94, 070404 (2005)] was overestimated. However, we are able to show that the small gap found in the Abelian scenario dramatically increases if we turn to non-Abelian fields squeezing the Landau levels.

  4. Realization of ground-state artificial skyrmion lattices at room temperature

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

    Gilbert, Dustin A.; Maranville, Brian B.; Balk, Andrew L.; Kirby, Brian J.; Fischer, Peter; Pierce, Daniel T.; Unguris, John; Borchers, Julie A.; Liu, Kai

    2015-10-08

    We report that the topological nature of magnetic skyrmions leads to extraordinary properties that provide new insights into fundamental problems of magnetism and exciting potentials for novel magnetic technologies. Prerequisite are systems exhibiting skyrmion lattices at ambient conditions, which have been elusive so far. We demonstrate the realization of artificial Bloch skyrmion lattices over extended areas in their ground state at room temperature by patterning asymmetric magnetic nanodots with controlled circularity on an underlayer with perpendicular magnetic anisotropy (PMA). Polarity is controlled by a tailored magnetic field sequence and demonstrated in magnetometry measurements. The vortex structure is imprinted from themore » dots into the interfacial region of the underlayer via suppression of the PMA by a critical ion-irradiation step. In conclusion, the imprinted skyrmion lattices are identified directly with polarized neutron reflectometry and confirmed by magnetoresistance measurements. Our results demonstrate an exciting platform to explore room-temperature ground-state skyrmion lattices.« less

  5. New vector for transfer of yeast artificial chromosomes to mammalian cells

    SciTech Connect (OSTI)

    Markie, D.; Ragoussis, J.; Senger, G.; Rowan, A.; Trowsdale, J.; Sheer, D.; Bodmer, W.F. ); Sansom, D. )

    1993-03-01

    A modification vector has been constructed to facilitate the transfer of yeast artificial chromosomes (YACs) to mammalian cells in culture by targeting a dominant selectable marker (G418 resistance) to the right arm of pYAC4 clones. The ADE2 gene is used for yeast selection with consequent disruption of the URA3 gene, allowing direct modification of YACs within the common host strain AB1380, and providing a simple test for correct targeting. This vector has been tested by modification of a 550-kb YAC containing part of the human MHC class II region and transfer to CHO cells by protoplast fusion. Analysis of 15 independent G418-resistant CHO lines obtained following fusion suggests the majority contain a complete YAC with moderate amplification in some lines. 24 refs., 4 figs.

  6. Prediction of Weld Penetration in FCAW of HSLA steel using Artificial Neural Networks

    SciTech Connect (OSTI)

    Asl, Y. Dadgar; Mostafa, N. B.; Panahizadeh, V. R. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Seyedkashi, S. M. H. [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2011-01-17

    Flux-cored arc welding (FCAW) is a semiautomatic or automatic arc welding process that requires a continuously-fed consumable tubular electrode containing a flux. The main FCAW process parameters affecting the depth of penetration are welding current, arc voltage, nozzle-to-work distance, torch angle and welding speed. Shallow depth of penetration may contribute to failure of a welded structure since penetration determines the stress-carrying capacity of a welded joint. To avoid such occurrences; the welding process parameters influencing the weld penetration must be properly selected to obtain an acceptable weld penetration and hence a high quality joint. Artificial neural networks (ANN), also called neural networks (NN), are computational models used to express complex non-linear relationships between input and output data. In this paper, artificial neural network (ANN) method is used to predict the effects of welding current, arc voltage, nozzle-to-work distance, torch angle and welding speed on weld penetration depth in gas shielded FCAW of a grade of high strength low alloy steel. 32 experimental runs were carried out using the bead-on-plate welding technique. Weld penetrations were measured and on the basis of these 32 sets of experimental data, a feed-forward back-propagation neural network was created. 28 sets of the experiments were used as the training data and the remaining 4 sets were used for the testing phase of the network. The ANN has one hidden layer with eight neurons and is trained after 840 iterations. The comparison between the experimental results and ANN results showed that the trained network could predict the effects of the FCAW process parameters on weld penetration adequately.

  7. Stereotactic Body Radiotherapy: A Promising Treatment Option for the Boost of Oropharyngeal Cancers Not Suitable for Brachytherapy: A Single-Institutional Experience

    SciTech Connect (OSTI)

    Al-Mamgani, Abrahim; Tans, Lisa; Teguh, David N.; Rooij, Peter van; Zwijnenburg, Ellen M.; Levendag, Peter C.

    2012-03-15

    Purpose: To prospectively assess the outcome and toxicity of frameless stereotactic body radiotherapy (SBRT) as a treatment option for boosting primary oropharyngeal cancers (OPC) in patients who not suitable for the standard brachytherapy boost (BTB). Methods and Materials: Between 2005 and 2010, 51 patients with Stage I to IV biopsy-proven OPC who were not suitable for BTB received boosts by means of SBRT (3 times 5.5 Gy, prescribed to the 80% isodose line), after 46 Gy of IMRT to the primary tumor and neck (when indicated). Endpoints of the study were local control (LC), disease-free survival (DFS), overall survival (OS), and acute and late toxicity. Results: After a median follow-up of 18 months (range, 6-65 months), the 2-year actuarial rates of LC, DFS, and OS were 86%, 80%, and 82%, respectively, and the 3-year rates were 70%, 66%, and 54%, respectively. The treatment was well tolerated, as there were no treatment breaks and no Grade 4 or 5 toxicity reported, either acute or chronic. The overall 2-year cumulative incidence of Grade {>=}2 late toxicity was 28%. Of the patients with 2 years with no evidence of disease (n = 20), only 1 patient was still feeding tube dependent and 2 patients had Grade 3 xerostomia. Conclusions: According to our knowledge, this study is the first report of patients with primary OPC who received boosts by means of SBRT. Patients with OPC who are not suitable for the standard BTB can safely and effectively receive boosts by SBRT. With this radiation technique, an excellent outcome was achieved. Furthermore, the SBRT boost did not have a negative impact regarding acute and late side effects.

  8. Evaluation of Suitability of Selected Set of Department of Defense Military Bases and Department of Energy Facilities for Siting a Small Modular Reactor

    SciTech Connect (OSTI)

    Poore III, Willis P; Belles, Randy; Mays, Gary T; Omitaomu, Olufemi A

    2013-03-01

    This report summarizes the approach that ORNL developed for screening a sample set of US Department of Defense (DOD) military base sites and DOE sites for possible powering with an SMR; the methodology employed, including spatial modeling; and initial results for several sample sites. The objective in conducting this type of siting evaluation is demonstrate the capability to characterize specific DOD and DOE sites to identify any particular issues associated with powering the sites with an SMR using OR-SAGE; it is not intended to be a definitive assessment per se as to the absolute suitability of any particular site.

  9. ZPR-3 Assembly 12 : A cylindrical assembly of highly enriched uranium, depleted uranium and graphite with an average {sup 235}U enrichment of 21 atom %.

    SciTech Connect (OSTI)

    Lell, R. M.; McKnight, R. D.; Perel, R. L.; Wagschal, J. J.; Nuclear Engineering Division; Racah Inst. of Physics

    2010-09-30

    Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR critical assemblies have been evaluated as ICSBEP and IRPhEP benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. ZPR-3 Assembly 12 (ZPR-3/12) was designed as a fast reactor physics benchmark experiment with an average core {sup 235}U enrichment of approximately 21 at.%. Approximately 68.9% of the total fissions in this assembly occur above 100 keV, approximately 31.1% occur below 100 keV, and essentially none below 0.625 eV - thus the classification as a 'fast' assembly. This assembly is Fast Reactor Benchmark No. 9 in the Cross Section Evaluation Working Group (CSEWG) Benchmark Specifications and has historically been used as a data validation benchmark assembly. Loading of ZPR-3 Assembly 12 began in late Jan. 1958, and the Assembly 12 program ended in Feb. 1958. The core consisted of highly enriched uranium (HEU) plates, depleted uranium plates and graphite plates loaded into stainless steel drawers which were inserted into the central square stainless steel tubes of a 31 x 31 matrix on a split table machine. The core unit cell consisted of two columns of 0.125 in.-wide (3.175 mm) HEU plates, seven columns of 0.125 in.-wide depleted uranium plates and seven columns of 0.125 in.-wide graphite plates. The length of each column was 9 in. (228.6 mm) in each half of the core. The graphite plates were included to produce a softer neutron spectrum that would be more characteristic of a large power reactor. The axial blanket consisted of 12 in. (304.8 mm) of depleted uranium behind the core. The thickness of the radial blanket was approximately 12 in. and the length of the radial blanket in each half of the matrix was 21 in. (533.4 mm). The assembly geometry approximated a right circular cylinder as closely as the square matrix tubes allowed. According to the logbook and loading records for ZPR-3/12, the reference critical configuration was loading 10 which was critical on Feb. 5, 1958. The subsequent loadings were very similar but less clean for criticality because there were modifications made to accommodate reactor physics measurements other than criticality. Accordingly, ZPR-3/12 loading 10 was selected as the only configuration for this benchmark. As documented below, it was determined to be acceptable as a criticality safety benchmark experiment. An accurate transformation to a simplified model is needed to make any ZPR assembly a practical criticality-safety benchmark. There is simply too much geometric detail in an exact (as-built) model of a ZPR assembly, even a clean core such as ZPR-3/12 loading 10. The transformation must reduce the detail to a practical level without masking any of the important features of the critical experiment. And it must d

  10. Synthesis and CO{sub 2} adsorption study of modified MOF-5 with multi-wall carbon nanotubes and expandable graphite

    SciTech Connect (OSTI)

    Ullah, Sami E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com; Bustam, M. A. E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com; Shariff, A. M. E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com; Elkhalifah, Ali E. I. E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com; Murshid, G. E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com; Riaz, Nadia E-mail: azmibustam@petronas.com.my E-mail: lkhlfh@gmail.com E-mail: nadiariazz@gmail.com

    2014-10-24

    MOF-5 was synthesized by solvothermal method and its reactivation under anhydrous conditions. This research is conducted to investigate the effect of MOF-5 and MOF-5 modified with multi-wall carbon nanotubes (MWCNTs) and expandable graphite (EG) on the performance of CO{sub 2} adsorption. The synthesized MOFs were characterized using Field emission scanning electron microscopy (FESEM) for surface morphology, Thermogravimetric analysis (TGA) for thermal stability, X-ray diffraction (XRD) for crystals plane, Brunauer-Emmet-Teller (BET) for surface area and CO{sub 2} adsorption. The result had showed that the modified MOF-5 enhanced the CO{sub 2} adsorption compared to the pure MOF-5. The increment in the CO{sub 2} uptake capacities of MOF materials was attributed to the decrease in the pore size and enhancement of micropore volume of MOF-5 by multi-walled carbon nanotube and EG incorporation. The BET surface area of the synthesized MOF-5@MWCNTs is more than MOF-5. The CO{sub 2} sorption capacities of MOF-5 and MOF-5@MWCNTs were observed to increase from 0.00008 to 0.00048 mol g-1 at 298 K and 1 bar. The modified MOF-5@MWCNTs resulted in the highest CO{sub 2} adsorption followed by the modified MOF-5@ EG and lastly, MOF-5.

  11. 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; Majumder, Chiranjib

    2014-04-28

    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 AgAg bonds in the cluster and energy gain from AgC 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.

  12. Evaluating the Potential for Marine and Hydrokinetic Devices to Act as Artificial Reefs or Fish Aggregating Devices. Based on Analysis of Surrogates in Tropical, Subtropical, and Temperate U.S. West Coast and Hawaiian Coastal Waters

    SciTech Connect (OSTI)

    Kramer, Sharon H.; Hamilton, Christine D.; Spencer, Gregory C.; Ogston, Heather O.

    2015-05-12

    Wave energy converters (WECs) and tidal energy converters (TECs) are only beginning to be deployed along the U.S. West Coast and in Hawai‘i, and a better understanding of their ecological effects on fish, particularly on special-status fish (e.g., threatened and endangered) is needed to facilitate project design and environmental permitting. The structures of WECs and TECs placed on to the seabed, such as anchors and foundations, may function as artificial reefs that attract reef-associated fishes, while the midwater and surface structures, such as mooring lines, buoys, and wave or tidal power devices, may function as fish aggregating devices (FADs), forming the nuclei for groups of fishes. Little is known about the potential for WECs and TECs to function as artificial reefs and FADs in coastal waters of the U.S. West Coast and Hawai‘i. We evaluated these potential ecological interactions by reviewing relevant information about fish associations with surrogate structures, such as artificial reefs, natural reefs, kelps, floating debris, oil and gas platforms, marine debris, anchored FADs deployed to enhance fishing opportunities, net-cages used for mariculture, and piers and docks. Based on our review, we postulate that the structures of WECs and TECs placed on or near the seabed in coastal waters of the U.S. West Coast and Hawai‘i likely will function as small-scale artificial reefs and attract potentially high densities of reef-associated fishes (including special-status rockfish species [Sebastes spp.] along the mainland), and that the midwater and surface structures of WECs placed in the tropical waters of Hawai‘i likely will function as de facto FADs with species assemblages varying by distance from shore and deployment depth. Along the U.S. West Coast, frequent associations with midwater and surface structures may be less likely: juvenile, semipelagic, kelp-associated rockfishes may occur at midwater and surface structures of WECs in coastal waters of southern California to Washington, and occasional, seasonal, or transitory associations of coastal pelagic fishes such as jack mackerel (Trachurus symmetricus) may also occur at WECs in these waters. Importantly, our review indicated that negative effects of WEC structures on special-status fish species, such as increased predation of juvenile salmonids or rockfishes, are not likely. In addition, WECs installed in coastal California, especially in southern California waters, have the potential to attract high densities of reef-associated fishes and may even contribute to rockfish productivity, if fish respond to the WECs similarly to oil and gas platforms, which have some of the highest secondary production per unit area of seafloor of any marine habitat studied globally (Claisse et al. 2014). We encountered some information gaps, owing to the paucity or lack, in key locations, of comparable surrogate structures in which fish assemblages and ecological interactions were studied. TECs are most likely to be used in the Puget Sound area, but suitable surrogates are lacking there. However, in similarly cold-temperate waters of Europe and Maine, benthopelagic fish occurred around tidal turbines during lower tidal velocities, and this type of interaction may be expected by similar species at TECs in Puget Sound. To address information gaps in the near term, such as whether WECs would function as FADs in temperate waters, studies of navigation buoys using hydroacoustics are recommended.

  13. Optimizing artificial lift operations through the use of wireless conveyed real time bottom hole data

    SciTech Connect (OSTI)

    Campbell, B.; MacKinnon, J.; Bandy, T.R.; Hampton, T.

    1996-12-31

    The use of an innovative wireless bottom hole pressure/temperature telemetry acquisition system in artificial lift operations can dramatically improve efficiency and optimize fluid producing rates in those wells. The tool is installed into the producing well in the vicinity of the perforations, measuring and transmitting the producing bottom hole pressures and temperatures to the surface for instantaneous control of the surface pumping motor speed. This insures the lowest possible fluid level back pressures, thus allowing for the highest possible fluid entry into the wellbore from that reservoir`s capacity. Operating costs per barrel are lowered since the maximum oil production can now be realized from existing wells. The telemetry tool is deployed with standard slickline equipment and is installed inside a well in a manner similar to ordinary pressure recorder tools. Several unique advantages of the tool are: (1) no moving parts; (2) no wireline to the surface; (3) real time measurement of bottom hole data; and (4) slickline retrievable. Future versions of the acquisition system tool will improve operating efficiency in the following ways: (1) Temperature monitoring and control of perforation scaling, tubular waxing, and tubular hydrating plugs. (2) Provide data necessary to create diagnostically predictive IPR curves through monitoring of reservoir in-flow rates. (3) Enabling early warning of water encroachment or lensing through fluid resistivity monitoring.

  14. Nanocluster building blocks of artificial square spin ice: Stray-field studies of thermal dynamics

    SciTech Connect (OSTI)

    Pohlit, Merlin Porrati, Fabrizio; Huth, Michael; Müller, Jens

    2015-05-07

    We present measurements of the thermal dynamics of a Co-based single building block of an artificial square spin ice fabricated by focused electron-beam-induced deposition. We employ micro-Hall magnetometry, an ultra-sensitive tool to study the stray field emanating from magnetic nanostructures, as a new technique to access the dynamical properties during the magnetization reversal of the spin-ice nanocluster. The obtained hysteresis loop exhibits distinct steps, displaying a reduction of their “coercive field” with increasing temperature. Therefore, thermally unstable states could be repetitively prepared by relatively simple temperature and field protocols allowing one to investigate the statistics of their switching behavior within experimentally accessible timescales. For a selected switching event, we find a strong reduction of the so-prepared states' “survival time” with increasing temperature and magnetic field. Besides the possibility to control the lifetime of selected switching events at will, we find evidence for a more complex behavior caused by the special spin ice arrangement of the macrospins, i.e., that the magnetic reversal statistically follows distinct “paths” most likely driven by thermal perturbation.

  15. Reservoir Modeling by Data Integration via Intermediate Spaces and Artificial Intelligence Tools in MPS Simulation Frameworks

    SciTech Connect (OSTI)

    Ahmadi, Rouhollah; Khamehchi, Ehsan

    2013-12-15

    Conditioning stochastic simulations are very important in many geostatistical applications that call for the introduction of nonlinear and multiple-point data in reservoir modeling. Here, a new methodology is proposed for the incorporation of different data types into multiple-point statistics (MPS) simulation frameworks. Unlike the previous techniques that call for an approximate forward model (filter) for integration of secondary data into geologically constructed models, the proposed approach develops an intermediate space where all the primary and secondary data are easily mapped onto. Definition of the intermediate space, as may be achieved via application of artificial intelligence tools like neural networks and fuzzy inference systems, eliminates the need for using filters as in previous techniques. The applicability of the proposed approach in conditioning MPS simulations to static and geologic data is verified by modeling a real example of discrete fracture networks using conventional well-log data. The training patterns are well reproduced in the realizations, while the model is also consistent with the map of secondary data.

  16. Niobium-titanium superconductors produced by powder metallurgy having artificial flux pinning centers

    DOE Patents [OSTI]

    Jablonski, Paul D.; Larbalestier, David C.

    1993-01-01

    Superconductors formed by powder metallurgy have a matrix of niobium-titanium alloy with discrete pinning centers distributed therein which are formed of a compatible metal. The artificial pinning centers in the Nb-Ti matrix are reduced in size by processing steps to sizes on the order of the coherence length, typically in the range of 1 to 10 nm. To produce the superconductor, powders of body centered cubic Nb-Ti alloy and the second phase flux pinning material, such as Nb, are mixed in the desired percentages. The mixture is then isostatically pressed, sintered at a selected temperature and selected time to produce a cohesive structure having desired characteristics without undue chemical reaction, the sintered billet is reduced in size by deformation, such as by swaging, the swaged sample receives heat treatment and recrystallization and additional swaging, if necessary, and is then sheathed in a normal conducting sheath, and the sheathed material is drawn into a wire. The resulting superconducting wire has second phase flux pinning centers distributed therein which provide enhanced J.sub.ct due to the flux pinning effects.

  17. Using Artificial Neural Networks to Forecast Trichloroethylene Concentrations at the Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Kopp, Joshua D

    2007-05-01

    To determine the future extent of the TCE contamination plume at PGDP, a groundwater and solute transport model has been developed by the Department of Energy (DOE). The model used to perform these calculations is MODFLOWT which is an enhanced groundwater transport model developed by the United States Geological Survey (USGS). MODFLOWT models groundwater movement as well as the transport of species that are subject to adsorption and decay by using a finite difference method (Duffield et al 2001). A significant limitation of MODFLOWT is that it requires large amounts of data. This data can be difficult and expensive to obtain. MODFLOWT also requires excessive computational time to perform one simulation. It is desirable to have a model that can predict the spatial extent of the contaminant plume without as much required data and that does not require excessive computational times. The purpose of this study is to develop and alternative model to MODFLOWT that can produce similar results for possible use in a companion management model. The alternative model used in this study is an artificial neural network (ANN).

  18. Joint Center for Artificial Photosynthesis (JCAP): DOE's Solar Fuels Energy Innovation Hub (2011 EFRC Summit)

    ScienceCinema (OSTI)

    Lewis, Nate (Director, Joint Center for Artificial Photosynthesis and Professor at Caltech)

    2012-03-14

    The Joint Center for Artificial Photosynthesis (JCAP) is a DOE Energy Innovation Hub focused on fuels from sunlight. JCAP's Director, Nate Lewis, spoke at the 2011 EFRC Summit about what JCAP is and how it is partnering with the EFRC community to accelerate the progress towards new solar fuels. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several ?grand challenges? and use-inspired ?basic research needs? recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.

  19. Application of artificial intelligence to reservoir characterization: An interdisciplinary approach. Final report, August 31, 1997

    SciTech Connect (OSTI)

    Kerr, D.R.; Thompson, L.G.; Shenoi, S.

    1998-03-01

    The primary goal of the project is to develop a user-friendly computer program to integrate geological and engineering information using Artificial Intelligence (AI) methodology. The project is restricted to fluvially dominated deltaic environments. The static information used in constructing the reservoir description includes well core and log data. Using the well core and the log data, the program identifies the marker beds, and the type of sand facies, and in turn, develops correlations between wells. Using the correlations and sand facies, the program is able to generate multiple realizations of sand facies and petrophysical properties at interwell locations using geostatistical techniques. The generated petrophysical properties are used as input in the next step where the production data are honored. By adjusting the petrophysical properties, the match between the simulated and the observed production rates is obtained. Although all the components within the overall system are functioning, the integration of dynamic data may not be practical due to the single-phase flow limitations and the computationally intensive algorithms. The future work needs to concentrate on making the dynamic data integration computationally efficient.

  20. Delineating Rearrangements in Single Yeast Artificial Chromosomes by Quantitative DNA Fiber Mapping

    SciTech Connect (OSTI)

    Weier, Heinz-Ulrich G.; Greulich-Bode, Karin M.; Wu, Jenny; Duell, Thomas

    2009-09-18

    Cloning of large chunks of human genomic DNA in recombinant systems such as yeast or bacterial artificial chromosomes has greatly facilitated the construction of physical maps, the positional cloning of disease genes or the preparation of patient-specific DNA probes for diagnostic purposes. For this process to work efficiently, the DNA cloning process and subsequent clone propagation need to maintain stable inserts that are neither deleted nor otherwise rearranged. Some regions of the human genome; however, appear to have a higher propensity than others to rearrange in any host system. Thus, techniques to detect and accurately characterize such rearrangements need to be developed. We developed a technique termed 'Quantitative DNA Fiber Mapping (QDFM)' that allows accurate tagging of sequence elements of interest with near kilobase accuracy and optimized it for delineation of rearrangements in recombinant DNA clones. This paper demonstrates the power of this microscopic approach by investigating YAC rearrangements. In our examples, high-resolution physical maps for regions within the immunoglobulin lambda variant gene cluster were constructed for three different YAC clones carrying deletions of 95 kb and more. Rearrangements within YACs could be demonstrated unambiguously by pairwise mapping of cosmids along YAC DNA molecules. When coverage by YAC clones was not available, distances between cosmid clones were estimated by hybridization of cosmids onto DNA fibers prepared from human genomic DNA. In addition, the QDFM technology provides essential information about clone stability facilitating closure of the maps of the human genome as well as those of model organisms.

  1. Improved Pharmacological and Structural Properties of HIV Fusion Inhibitor AP3 over Enfuvirtide: Highlighting Advantages of Artificial Peptide Strategy

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

    Zhu, Xiaojie; Zhu, Yun; Ye, Sheng; Wang, Qian; Xu, Wei; Su, Shan; Sun, Zhiwu; Yu, Fei; Liu, Qi; Wang, Chao; et al

    2015-08-19

    Enfuvirtide (T20), is the first HIV fusion inhibitor approved for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral drugs. However, its clinical application is limited because of short half-life, drug resistance and cross-reactivity with the preexisting antibodies in HIV-infected patients. Using an artificial peptide strategy, we designed a peptide with non-native protein sequence, AP3, which exhibited potent antiviral activity against a broad spectrum of HIV-1 strains, including those resistant to T20, and had remarkably longer in vivo half-life than T20. While the preexisting antibodies in HIV-infected patients significantly suppressed T20’s antiviral activity, these antibodies neither recognizedmore » AP3, nor attenuated its anti-HIV-1 activity. Structurally different from T20, AP3 could fold into single-helix and interact with gp41 NHR. The two residues, Met and Thr, at the N-terminus of AP3 form a hook-like structure to stabilize interaction between AP3 and NHR helices. Therefore, AP3 has potential for further development as a new HIV fusion inhibitor with improved antiviral efficacy, resistance profile and pharmacological properties over enfuvirtide. Meanwhile, this study highlighted the advantages of artificially designed peptides, and confirmed that this strategy could be used in developing artificial peptide-based viral fusion inhibitors against HIV and other enveloped viruses.« less

  2. Report of the Peer Review Panel on the early site suitability evaluation of the Potential Repository Site at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

    SciTech Connect (OSTI)

    1992-01-01

    The US Department of Energy (DOE) Yucca mountain Site Characterization Project Office (YMPO) assigned Science Applications International Corporation (SAIC), the Technical and Management Support Services (T&MSS) contractor to the YmPo, the task of conducting an Early Site Suitability Evaluation (ESSE) of the Yucca mountain site as a potential site for a high-level radioactive waste repository. First, the assignment called for the development of a method to evaluate a single site against the DOE General Guidelines for Recommendation of Sites for Nuclear Waste Repositories, 10 CFR Part 960. Then, using this method, an evaluation team, the ESSE Core Team, of senior YMP scientists, engineers, and technical experts, evaluated new information obtained about the site since publication of the final Environmental Assessment (DOE, 1986) to determine if new suitability/unsuitability findings could be recommended. Finally, the Core Team identified further information and analyses needed to make final determinations for each of the guidelines. As part of the task, an independent peer review of the ESSE report has been conducted. Expertise was solicited that covered the entire spectrum of siting guidelines in 10 CFR Part 960 in order to provide a complete, in-depth critical review of the data evaluated and cited in the ESSE report, the methods used to evaluate the data, and the conclusions and recommendations offered by the report. Fourteen nationally recognized technical experts (Table 2) served on the Peer Review Panel. The comments from the Panel and the responses prepared by the ESSE Core Team, documented on formal Comment Response Forms, constitute the body of this document.

  3. RAVEN: a GUI and an Artificial Intelligence Engine in a Dynamic PRA Framework

    SciTech Connect (OSTI)

    C. Rabiti; D. Mandelli; A. Alfonsi; J. Cogliati; R. Kinoshita; D. Gaston; R. Martineau; C. Curtis

    2013-06-01

    Increases in computational power and pressure for more accurate simulations and estimations of accident scenario consequences are driving the need for Dynamic Probabilistic Risk Assessment (PRA) [1] of very complex models. While more sophisticated algorithms and computational power address the back end of this challenge, the front end is still handled by engineers that need to extract meaningful information from the large amount of data and build these complex models. Compounding this problem is the difficulty in knowledge transfer and retention, and the increasing speed of software development. The above-described issues would have negatively impacted deployment of the new high fidelity plant simulator RELAP-7 (Reactor Excursion and Leak Analysis Program) at Idaho National Laboratory. Therefore, RAVEN that was initially focused to be the plant controller for RELAP-7 will help mitigate future RELAP-7 software engineering risks. In order to accomplish this task, Reactor Analysis and Virtual Control Environment (RAVEN) has been designed to provide an easy to use Graphical User Interface (GUI) for building plant models and to leverage artificial intelligence algorithms in order to reduce computational time, improve results, and help the user to identify the behavioral pattern of the Nuclear Power Plants (NPPs). In this paper we will present the GUI implementation and its current capability status. We will also introduce the support vector machine algorithms and show our evaluation of their potentiality in increasing the accuracy and reducing the computational costs of PRA analysis. In this evaluation we will refer to preliminary studies performed under the Risk Informed Safety Margins Characterization (RISMC) project of the Light Water Reactors Sustainability (LWRS) campaign [3]. RISMC simulation needs and algorithm testing are currently used as a guidance to prioritize RAVEN developments relevant to PRA.

  4. An Adaptive Landscape Classification Procedure using Geoinformatics and Artificial Neural Networks

    SciTech Connect (OSTI)

    Coleman, Andre M.

    2008-08-01

    The Adaptive Landscape Classification Procedure (ALCP), which links the advanced geospatial analysis capabilities of Geographic Information Systems (GISs) and Artificial Neural Networks (ANNs) and particularly Self-Organizing Maps (SOMs), is proposed as a method for establishing and reducing complex data relationships. Its adaptive and evolutionary capability is evaluated for situations where varying types of data can be combined to address different prediction and/or management needs such as hydrologic response, water quality, aquatic habitat, groundwater recharge, land use, instrumentation placement, and forecast scenarios. The research presented here documents and presents favorable results of a procedure that aims to be a powerful and flexible spatial data classifier that fuses the strengths of geoinformatics and the intelligence of SOMs to provide data patterns and spatial information for environmental managers and researchers. This research shows how evaluation and analysis of spatial and/or temporal patterns in the landscape can provide insight into complex ecological, hydrological, climatic, and other natural and anthropogenic-influenced processes. Certainly, environmental management and research within heterogeneous watersheds provide challenges for consistent evaluation and understanding of system functions. For instance, watersheds over a range of scales are likely to exhibit varying levels of diversity in their characteristics of climate, hydrology, physiography, ecology, and anthropogenic influence. Furthermore, it has become evident that understanding and analyzing these diverse systems can be difficult not only because of varying natural characteristics, but also because of the availability, quality, and variability of spatial and temporal data. Developments in geospatial technologies, however, are providing a wide range of relevant data, and in many cases, at a high temporal and spatial resolution. Such data resources can take the form of high-dimensional data arrays, which can difficult to fully use. Establishing relationships among high-dimensional datasets through neurocomputing based patterning methods can help 1) resolve large volumes of data into a meaningful form; 2) provide an approach for inferring landscape processes in areas that have limited data available but that exhibit similar landscape characteristics; and 3) discover the value of individual variables or groups of variables that contribute to specific processes in the landscape.

  5. Pyrotek Graphitization Facility Expansion Project

    Broader source: Energy.gov [DOE]

    2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

  6. Evaluating the Suitability for CO2 Storage at the FutureGen 2.0 Site, Morgan County, Illinois, USA

    SciTech Connect (OSTI)

    Bonneville, Alain; Gilmore, Tyler J.; Sullivan, E. C.; Vermeul, Vincent R.; Kelley, Mark E.; White, Signe K.; Appriou, Delphine; Bjornstad, Bruce N.; Gerst, Jacqueline L.; Gupta, Neeraj; Horner, Jacob A.; McNeil, Caitlin; Moody, Mark A.; Rike, William M.; Spane, Frank A.; Thorne, Paul D.; Zeller, Evan R.; Zhang, Z. F.; Hoffman, Jeffrey; Humphreys, Kenneth K.

    2013-08-05

    FutureGen 2.0 site will be the first near-zero emission power plant with fully integrated long-term storage in a deep, non-potable saline aquifer in the United States. The proposed FutureGen 2.0 CO2 storage site is located in northeast Morgan County, Illinois, U.S.A., forty-eight kilometres from the Meredosia Energy Center where a large-scale oxy-combustion demonstration will be conducted. The demonstration will involve > 90% carbon capture, which will produce more than one million metric tons (MMT) of CO2 per year. The CO2 will be compressed at the power plant and transported via pipeline to the storage site. To examine CO2 storage potential of the site, a 1,467m characterization well (FGA#1) was completed in December 2011. The target reservoir for CO2 storage is the Mt. Simon Sandstone and Elmhurst Sandstone Member of the lower Eau Claire Formation for a combined thickness of 176 m. Confining beds of the overlying Lombard and Proviso Members (upper Eau Claire Formation) reach a thickness of 126 m. Characterization of the target injection zone and the overlying confining zone was based on wellbore data, cores, and geophysical logs, along with surface geophysical (2-D seismic profiles, magnetic and gravity), and structural data collected during the initial stage of the project . Based on this geological model, 3D simulations of CO2 injection and redistribution were conducted using STOMP-CO2, a multiphase flow and transport simulator. After this characterization stage, it appears that the injection site is a suitable geologic system for CO2 sequestration and that the injection zone is sufficient to receive up to 33 MMT of CO2 at a rate of 1.1 MMT/yr. GHGT-11 conference

  7. Accuracy of the electron transport in mcnp5 and its suitability for ionization chamber response simulations: A comparison with the egsnrc and penelope codes

    SciTech Connect (OSTI)

    Koivunoro, Hanna; Siiskonen, Teemu; Kotiluoto, Petri; Auterinen, Iiro; Hippelaeinen, Eero; Savolainen, Sauli

    2012-03-15

    Purpose: In this work, accuracy of the mcnp5 code in the electron transport calculations and its suitability for ionization chamber (IC) response simulations in photon beams are studied in comparison to egsnrc and penelope codes. Methods: The electron transport is studied by comparing the depth dose distributions in a water phantom subdivided into thin layers using incident energies (0.05, 0.1, 1, and 10 MeV) for the broad parallel electron beams. The IC response simulations are studied in water phantom in three dosimetric gas materials (air, argon, and methane based tissue equivalent gas) for photon beams ({sup 60}Co source, 6 MV linear medical accelerator, and mono-energetic 2 MeV photon source). Two optional electron transport models of mcnp5 are evaluated: the ITS-based electron energy indexing (mcnp5{sub ITS}) and the new detailed electron energy-loss straggling logic (mcnp5{sub new}). The electron substep length (ESTEP parameter) dependency in mcnp5 is investigated as well. Results: For the electron beam studies, large discrepancies (>3%) are observed between the mcnp5 dose distributions and the reference codes at 1 MeV and lower energies. The discrepancy is especially notable for 0.1 and 0.05 MeV electron beams. The boundary crossing artifacts, which are well known for the mcnp5{sub ITS}, are observed for the mcnp5{sub new} only at 0.1 and 0.05 MeV beam energies. If the excessive boundary crossing is eliminated by using single scoring cells, the mcnp5{sub ITS} provides dose distributions that agree better with the reference codes than mcnp5{sub new}. The mcnp5 dose estimates for the gas cavity agree within 1% with the reference codes, if the mcnp5{sub ITS} is applied or electron substep length is set adequately for the gas in the cavity using the mcnp5{sub new}. The mcnp5{sub new} results are found highly dependent on the chosen electron substep length and might lead up to 15% underestimation of the absorbed dose. Conclusions: Since the mcnp5 electron transport calculations are not accurate at all energies and in every medium by general clinical standards, caution is needed, if mcnp5 is used with the current electron transport models for dosimetric applications.

  8. Potential applications of artificial intelligence in computer-based management systems for mixed waste incinerator facility operation

    SciTech Connect (OSTI)

    Rivera, A.L.; Singh, S.P.N.; Ferrada, J.J.

    1991-01-01

    The Department of Energy/Oak Ridge Field Office (DOE/OR) operates a mixed waste incinerator facility at the Oak Ridge K-25 Site, designed for the thermal treatment of incinerable liquid, sludge, and solid waste regulated under the Toxic Substances Control Act (TSCA) and the Resource Conversion and Recovery Act (RCRA). Operation of the TSCA Incinerator is highly constrained as a result of the regulatory, institutional, technical, and resource availability requirements. This presents an opportunity for applying computer technology as a technical resource for mixed waste incinerator operation to facilitate promoting and sustaining a continuous performance improvement process while demonstrating compliance. This paper describes mixed waste incinerator facility performance-oriented tasks that could be assisted by Artificial Intelligence (AI) and the requirements for AI tools that would implement these algorithms in a computer-based system. 4 figs., 1 tab.

  9. Framework for a physical map of the human 22q13 region using bacterial artificial chromosomes (BACs)

    SciTech Connect (OSTI)

    Schmitt, H.; Kim, Ung-Jin; Slepak, T.

    1996-04-01

    Detailed physical maps of entire chromosomes based on combined genetic, cytogenetic, and structural information are essential components for positional cloning and genomic sequencing. Despite the wealth of genetic information of the known diseases in the chromosome 22q13 region, the construction of a detailed physical map of the terminal region is difficult due to the sparsity of the genetic markers. We present here a map of bacterial artificial chromosome (BAC) contigs that cover a number of genetic loci in the 22q13 region. One hundred thirty-six BACs with an average insert size of 140 kb are assembled into 35 contigs defined by 64 markers in 22q13-qter. Twenty-three anonymous markers are now linked to the previously mapped genetic anchor points. 55 refs., 4 figs., 3 tabs.

  10. Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials

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

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The AlxSc1-xN alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizingmore » the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt AlxSc1-xN alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt AlxSc1-xN alloys enable high quality epitaxial rocksalt metal/AlxSc1-xN superlattices with a wide range of accessible metamaterials properties.« less

  11. Diagnostics and Control of Natural Gas-Fired furnaces via Flame Image Analysis using Machine Vision & Artificial Intelligence Techniques

    SciTech Connect (OSTI)

    Shahla Keyvan

    2005-12-01

    A new approach for the detection of real-time properties of flames is used in this project to develop improved diagnostics and controls for natural gas fired furnaces. The system utilizes video images along with advanced image analysis and artificial intelligence techniques to provide virtual sensors in a stand-alone expert shell environment. One of the sensors is a flame sensor encompassing a flame detector and a flame analyzer to provide combustion status. The flame detector can identify any burner that has not fired in a multi-burner furnace. Another sensor is a 3-D temperature profiler. One important aspect of combustion control is product quality. The 3-D temperature profiler of this on-line system is intended to provide a tool for a better temperature control in a furnace to improve product quality. In summary, this on-line diagnostic and control system offers great potential for improving furnace thermal efficiency, lowering NOx and carbon monoxide emissions, and improving product quality. The system is applicable in natural gas-fired furnaces in the glass industry and reheating furnaces used in steel and forging industries.

  12. A Preclinical Study of the Safety and Efficacy of Occlusin Trade-Mark-Sign 500 Artificial Embolization Device in Sheep

    SciTech Connect (OSTI)

    Owen, Richard J.; Nation, Patrick N.; Polakowski, Robert; Biliske, Jennifer A.; Tiege, Paul B.

    2012-06-15

    Introduction: This study evaluated the safety, effectiveness, and biodegradation of a new embolic agent, Occlusin Trade-Mark-Sign 503 Artificial Embolization Device (OCL 503). The agent consists of biodegradable poly-lactic-co-glycolic acid microspheres (150-212 {mu}m) coated with type I bovine collagen and was compared with Embosphere{sup Registered-Sign} Microspheres (300-500 {mu}m) in this controlled study of uterine artery embolization (UAE) in sheep. Methods: Unilateral UAE was performed in 32 adult ewes randomly assigned. Vessels were embolized to effective stasis. The cohort was divided into four groups, which were sacrificed at 1, 3, 6, and 12 months. Results: Both agents were 100% effective in achieving stasis. At 6 months, all OCL 503-treated arteries were occluded, the microspheres degraded with time, and at 12 months all four animals examined demonstrated recanalization. OCL 503 was found in the untreated uterine artery in one animal with no other evidence of non target embolization. In the Embosphere-treated group, all vessels remained occluded and microspheres were detected in the contralateral uterine artery in 6 of 15 examined vessels and in 10 vaginal, 2 ovarian, and 1 vesical artery. No procedural-related complications were seen in either group. Conclusions: OCL 503 is as effective an embolic agent as Embosphere{sup Registered-Sign} Microspheres when embolizing ovine uterine arteries and resorbs with time, allowing recanalization of the treated arteries. No device-related issues or adverse events were observed.

  13. The use of artificial neural networks and multiple linear regression to predict rate of medical waste generation

    SciTech Connect (OSTI)

    Jahandideh, Sepideh Jahandideh, Samad; Asadabadi, Ebrahim Barzegari; Askarian, Mehrdad; Movahedi, Mohammad Mehdi; Hosseini, Somayyeh; Jahandideh, Mina

    2009-11-15

    Prediction of the amount of hospital waste production will be helpful in the storage, transportation and disposal of hospital waste management. Based on this fact, two predictor models including artificial neural networks (ANNs) and multiple linear regression (MLR) were applied to predict the rate of medical waste generation totally and in different types of sharp, infectious and general. In this study, a 5-fold cross-validation procedure on a database containing total of 50 hospitals of Fars province (Iran) were used to verify the performance of the models. Three performance measures including MAR, RMSE and R{sup 2} were used to evaluate performance of models. The MLR as a conventional model obtained poor prediction performance measure values. However, MLR distinguished hospital capacity and bed occupancy as more significant parameters. On the other hand, ANNs as a more powerful model, which has not been introduced in predicting rate of medical waste generation, showed high performance measure values, especially 0.99 value of R{sup 2} confirming the good fit of the data. Such satisfactory results could be attributed to the non-linear nature of ANNs in problem solving which provides the opportunity for relating independent variables to dependent ones non-linearly. In conclusion, the obtained results showed that our ANN-based model approach is very promising and may play a useful role in developing a better cost-effective strategy for waste management in future.

  14. Discrimination Analysis of Earthquakes and Man-Made Events Using ARMA Coefficients Determination by Artificial Neural Networks

    SciTech Connect (OSTI)

    AllamehZadeh, Mostafa

    2011-12-15

    A Quadratic Neural Networks (QNNs) model has been developed for identifying seismic source classification problem at regional distances using ARMA coefficients determination by Artificial Neural Networks (ANNs). We have devised a supervised neural system to discriminate between earthquakes and chemical explosions with filter coefficients obtained by windowed P-wave phase spectra (15 s). First, we preprocess the recording's signals to cancel out instrumental and attenuation site effects and obtain a compact representation of seismic records. Second, we use a QNNs system to obtain ARMA coefficients for feature extraction in the discrimination problem. The derived coefficients are then applied to the neural system to train and classification. In this study, we explore the possibility of using single station three-component (3C) covariance matrix traces from a priori-known explosion sites (learning) for automatically recognizing subsequent explosions from the same site. The results have shown that this feature extraction gives the best classifier for seismic signals and performs significantly better than other classification methods. The events have been tested, which include 36 chemical explosions at the Semipalatinsk test site in Kazakhstan and 61 earthquakes (mb = 5.0-6.5) recorded by the Iranian National Seismic Network (INSN). The 100% correct decisions were obtained between site explosions and some of non-site events. The above approach to event discrimination is very flexible as we can combine several 3C stations.

  15. Annual Review of BPA-Funded Projects in Natural and Artificial Propagation of Salmonids, March 27-29, 1985, Holiday Inn Airport, Portland, Oregon.

    SciTech Connect (OSTI)

    United States. Bonneville Power Administration.

    1985-04-01

    The Fish and Wildlife Division of Bonneville Power Administration (BPA) hosted a meeting for contractors to present the results of fiscal year 1984 research conducted to implement the Northwest Power Planning Council's Fish and Wildlife Program. The meeting focused on those projects specifically related to natural and artificial propagation of salmonids. The presentations were held at the Holiday Inn Airport in Portland, Oregon, on March 27-29, 1985. This document contains abstracts of the presentations from that meeting. Section 1 contains abstracts on artificial propagation, fish health, and downstream migration, and Section 2 contains abstracts on natural propagation and habitat improvement. The abstracts are indexed by BPA Project Number and by Fish and Wildlife Program Measure. The registered attendees at the meeting are listed alphabetically in Appendix A and by affiliation in Appendix B.

  16. Using artificial neural networks to predict the performance of a liquid sodium reflux pool boiler solar receiver

    SciTech Connect (OSTI)

    Fowler, M.M.; Klett, D.E.; Moreno, J.B.; Heermann, P.D.

    1997-03-01

    Liquid metal reflux receivers (LMRRs) have been designed to serve as the interface between the solar concentrator dish and the Stirling engine of a dish Stirling power system. Such a receiver has undergone performance testing at Sandia National Laboratory to determine cold- and hot-start characteristics, component temperatures, throughput power, and thermal efficiency, for various times of day and year. Performance modeling will play an important role in the future commercialization of these systems since it will be necessary to predict overall energy production for potential installation sites based on available meteorological data. As a supplement to numerical thermal modeling, artificial neural networks (ANNs) have been investigated for their effectiveness in predicting long-term energy production of a LMRR. Two types of data were used to train ANNs, actual on-sun test data, and ersatz data. ANNs were trained on both the raw on-sun test data and on pre-formatted versions of the data to determine if pre-formatting of the input data would improve network training efficiency and predictive abilities. Usable on-sun test data were available for only a few days of performance testing. Therefore, a set of year-long ersatz data was generated using a transient numerical model driven by one-minute meteorological data from the Solar Energy Meteorological Research and Training Sites (SEMRTS) data base for Davis, CA. The ersatz data were used to train ANNs based on warm-month data, cool-month data, and year-long data to investigate the impact of using seasonal test data on long-term predictive capabilities. The findings indicated that a network trained on data from a limited time span could successfully predict annual energy output of a liquid metal receiver.

  17. SU-E-T-206: Improving Radiotherapy Toxicity Based On Artificial Neural Network (ANN) for Head and Neck Cancer Patients

    SciTech Connect (OSTI)

    Cho, Daniel D; Wernicke, A Gabriella; Nori, Dattatreyudu; Chao, KSC; Parashar, Bhupesh; Chang, Jenghwa

    2014-06-01

    Purpose/Objective(s): The aim of this study is to build the estimator of toxicity using artificial neural network (ANN) for head and neck cancer patients Materials/Methods: An ANN can combine variables into a predictive model during training and considered all possible correlations of variables. We constructed an ANN based on the data from 73 patients with advanced H and N cancer treated with external beam radiotherapy and/or chemotherapy at our institution. For the toxicity estimator we defined input data including age, sex, site, stage, pathology, status of chemo, technique of external beam radiation therapy (EBRT), length of treatment, dose of EBRT, status of post operation, length of follow-up, the status of local recurrences and distant metastasis. These data were digitized based on the significance and fed to the ANN as input nodes. We used 20 hidden nodes (for the 13 input nodes) to take care of the correlations of input nodes. For training ANN, we divided data into three subsets such as training set, validation set and test set. Finally, we built the estimator for the toxicity from ANN output. Results: We used 13 input variables including the status of local recurrences and distant metastasis and 20 hidden nodes for correlations. 59 patients for training set, 7 patients for validation set and 7 patients for test set and fed the inputs to Matlab neural network fitting tool. We trained the data within 15% of errors of outcome. In the end we have the toxicity estimation with 74% of accuracy. Conclusion: We proved in principle that ANN can be a very useful tool for predicting the RT outcomes for high risk H and N patients. Currently we are improving the results using cross validation.

  18. SPECTRAL CLASSIFICATION OF GALAXIES AT 0.5 {<=} z {<=} 1 IN THE CDFS: THE ARTIFICIAL NEURAL NETWORK APPROACH

    SciTech Connect (OSTI)

    Teimoorinia, H.

    2012-12-01

    The aim of this work is to combine spectral energy distribution (SED) fitting with artificial neural network techniques to assign spectral characteristics to a sample of galaxies at 0.5 < z < 1. The sample is selected from the spectroscopic campaign of the ESO/GOODS-South field, with 142 sources having photometric data from the GOODS-MUSIC catalog covering bands between {approx}0.4 and 24 {mu}m in 10-13 filters. We use the CIGALE code to fit photometric data to Maraston's synthesis spectra to derive mass, specific star formation rate, and age, as well as the best SED of the galaxies. We use the spectral models presented by Kinney et al. as targets in the wavelength interval {approx}1200-7500 A. Then a series of neural networks are trained, with average performance {approx}90%, to classify the best SED in a supervised manner. We consider the effects of the prominent features of the best SED on the performance of the trained networks and also test networks on the galaxy spectra of Coleman et al., which have a lower resolution than the target models. In this way, we conclude that the trained networks take into account all the features of the spectra simultaneously. Using the method, 105 out of 142 galaxies of the sample are classified with high significance. The locus of the classified galaxies in the three graphs of the physical parameters of mass, age, and specific star formation rate appears consistent with the morphological characteristics of the galaxies.

  19. Artificial neural network implementation of chemistry with pdf simulation of H{sub 2}/CO{sub 2} flames

    SciTech Connect (OSTI)

    Christo, F.C.; Masri, A.R.; Nebot, E.M.

    1996-09-01

    A novel approach using artificial neural networks for representing chemical reactions is developed and successfully implemented with a modeled velocity-scalar joint pdf transport equation for H{sub 2}CO{sub 2} turbulent jet diffusion flames. The chemical kinetics are represented using a three-step reduced mechanism, and the transport equation is solved by a Monte Carlo method. A detailed analysis of computational performance and a comparison between the neural network approach and other methods used to represent the chemistry, namely the look-up table, or the direct integration procedures, are presented. A multilayer perceptron architecture is chosen for the neural network. The training algorithm is based on a back-propagation supervised learning procedure with individual momentum terms and adaptive learning rate adjustment for the weights matrix. A new procedure for the selection of training samples using dynamic randomization is developed and is aimed at reducing the possibility of the network being trapped in a local minimum. This algorithm achieved an impressive acceleration in convergence compared with the use of a fixed set of selected training samples. The optimization process of the neural network is discussed in detail. The feasibility of using neural network models to represent highly nonlinear chemical reactions is successfully illustrated. The prediction of the flow field and flame characteristics using the neural network approach is in good agreement with those obtained using other methods, and is also in reasonable agreement with the experimental data. The computational benefits of the neural network approach over the look-up table and the direct integration methods, both in CPU time and RAM storage requirements are not great for a chemical mechanisms of less than three reactions. The neural network approach becomes superior, however, for more complex reaction schemes.

  20. Radiation Characterization Summary: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline (ACRR-PLG-CC-32-cl).

    SciTech Connect (OSTI)

    Parma, Edward J.,; Vehar, David W.; Lippert, Lance L.; Griffin, Patrick J.; Naranjo, Gerald E.; Luker, Spencer M.

    2015-06-01

    This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the polyethylene-lead-graphite (PLG) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-PLG-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to David Ames for his assistance in running MCNP on the Sandia parallel machines.

  1. Electrode material comprising graphene-composite materials in...

    Office of Scientific and Technical Information (OSTI)

    Title: Electrode material comprising graphene-composite materials in a graphite network A durable electrode material suitable for use in Li ion batteries is provided. The material ...

  2. Artificial oxygen transport protein

    DOE Patents [OSTI]

    Dutton, P. Leslie

    2014-09-30

    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  3. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, C.T.

    1998-03-10

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

  4. Nickel aluminide alloy suitable for structural applications

    DOE Patents [OSTI]

    Liu, Chain T. (Oak Ridge, TN)

    1998-01-01

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

  5. Improved Pharmacological and Structural Properties of HIV Fusion Inhibitor AP3 over Enfuvirtide: Highlighting Advantages of Artificial Peptide Strategy

    SciTech Connect (OSTI)

    Zhu, Xiaojie; Zhu, Yun; Ye, Sheng; Wang, Qian; Xu, Wei; Su, Shan; Sun, Zhiwu; Yu, Fei; Liu, Qi; Wang, Chao; Zhang, Tianhong; Zhang, Zhenqing; Zhang, Xiaoyan; Xu, Jianqing; Du, Lanying; Liu, Keliang; Lu, Lu; Zhang, Rongguang; Jiang, Shibo

    2015-08-19

    Enfuvirtide (T20), is the first HIV fusion inhibitor approved for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral drugs. However, its clinical application is limited because of short half-life, drug resistance and cross-reactivity with the preexisting antibodies in HIV-infected patients. Using an artificial peptide strategy, we designed a peptide with non-native protein sequence, AP3, which exhibited potent antiviral activity against a broad spectrum of HIV-1 strains, including those resistant to T20, and had remarkably longer in vivo half-life than T20. While the preexisting antibodies in HIV-infected patients significantly suppressed T20’s antiviral activity, these antibodies neither recognized AP3, nor attenuated its anti-HIV-1 activity. Structurally different from T20, AP3 could fold into single-helix and interact with gp41 NHR. The two residues, Met and Thr, at the N-terminus of AP3 form a hook-like structure to stabilize interaction between AP3 and NHR helices. Therefore, AP3 has potential for further development as a new HIV fusion inhibitor with improved antiviral efficacy, resistance profile and pharmacological properties over enfuvirtide. Meanwhile, this study highlighted the advantages of artificially designed peptides, and confirmed that this strategy could be used in developing artificial peptide-based viral fusion inhibitors against HIV and other enveloped viruses.

  6. Artificial neural network modeling of the spontaneous combustion occurring in the industrial-scale coal stockpiles with 10-18 mm coal grain sizes

    SciTech Connect (OSTI)

    Ozdeniz, A.H.; Yilmaz, N.

    2009-07-01

    Companies consuming large amounts of coal should work with coal stocks in order to not face problems due to production delays. The industrial-scale stockpiles formed for the aforementioned reasons cause environmental problems and economic losses for the companies. This study was performed in a coal stock area of a large company in Konya, which uses large amounts of coal in its manufacturing units. The coal stockpile with 5 m width, 10 m length, 3 m height, and having 120 tons of weight was formed in the coal stock area of the company. The inner temperature data of the stockpile was recorded by 17 temperature sensors placed inside the stockpile at certain points. In order to achieve this goal, the electrical signal conversion of temperatures sensed by 17 temperature sensors placed in certain points inside the coal stockpile, the transfer of these electrical signals into computer media by using analog-digital conversion unit after applying necessary filtration and upgrading processes, and the record of these information into a database in particular time intervals are provided. Additionally, the data relating to the air temperature, air humidity, atmospheric pressure, wind velocity, and wind direction that are the parameters affecting the coal stockpile were also recorded. Afterwards, these measurement values were used for training and testing of an artificial neural network model. Comparison of the experimental and artificial neural network results, accuracy rates of training and testing were found to be 99.5% and 99.17%, respectively. It is shown that possible coal stockpile behavior with this artificial neural network model is powerfully estimated.

  7. Determining whether metals nucleate homogeneously on graphite...

    Office of Scientific and Technical Information (OSTI)

    Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for pages...

  8. Investigations of Cathode Architecture using Graphite Fibers

    Broader source: Energy.gov [DOE]

    2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

  9. Impact of artificial lateral quantum confinement on exciton-spin relaxation in a two-dimensional GaAs electronic system

    SciTech Connect (OSTI)

    Kiba, Takayuki Murayama, Akihiro; Tanaka, Toru; Tamura, Yosuke; Higo, Akio; Thomas, Cedric; Samukawa, Seiji

    2014-10-15

    We demonstrate the effect of artificial lateral quantum confinement on exciton-spin relaxation in a GaAs electronic system. GaAs nanodisks (NDs) were fabricated from a quantum well (QW) by top-down nanotechnology using neutral-beam etching aided by protein-engineered bio-nano-templates. The exciton-spin relaxation time was 1.4 ns due to ND formation, significantly extended compared to 0.44 ns for the original QW, which is attributed to weakening of the hole-state mixing in addition to freezing of the carrier momentum. The temperature dependence of the spin-relaxation time depends on the ND thickness, reflecting the degree of quantum confinement.

  10. Johnson Creek Artificial Propagation and Enhancement Project Operations and Maintenance Program; Brood Year 1998: Johnson Creek Chinook Salmon Supplementation, Biennial Report 1998-2000.

    SciTech Connect (OSTI)

    Daniel, Mitch; Gebhards, John

    2003-05-01

    The Nez Perce Tribe, through funding provided by the Bonneville Power Administration, has implemented a small scale chinook salmon supplementation program on Johnson Creek, a tributary in the South Fork of the Salmon River, Idaho. The Johnson Creek Artificial Propagation Enhancement project was established to enhance the number of threatened Snake River summer chinook salmon (Oncorhynchus tshawytscha) returning to Johnson Creek through artificial propagation. Adult chinook salmon collection and spawning began in 1998. A total of 114 fish were collected from Johnson Creek and 54 fish (20 males and 34 females) were retained for Broodstock. All broodstock were transported to Lower Snake River Compensation Plan's South Fork Salmon River adult holding and spawning facility, operated by the Idaho Department of Fish and Game. The remaining 60 fish were released to spawn naturally. An estimated 155,870 eggs from Johnson Creek chinook spawned at the South Fork Salmon River facility were transported to the McCall Fish Hatchery for rearing. Average fecundity for Johnson Creek females was 4,871. Approximately 20,500 eggs from females with high levels of Bacterial Kidney Disease were culled. This, combined with green-egg to eyed-egg survival of 62%, resulted in about 84,000 eyed eggs produced in 1998. Resulting juveniles were reared indoors at the McCall Fish Hatchery in 1999. All of these fish were marked with Coded Wire Tags and Visual Implant Elastomer tags and 8,043 were also PIT tagged. A total of 78,950 smolts were transported from the McCall Fish Hatchery and released directly into Johnson Creek on March 27, 28, 29, and 30, 2000.

  11. Synthesis and characterization of CuO nanofibers, and investigation for its suitability as blocking layer in ZnO NPs based dye sensitized solar cell and as photocatalyst in organic dye degradation

    SciTech Connect (OSTI)

    Sahay, R.; Sundaramurthy, J.; Suresh Kumar, P.; Thavasi, V.; Mhaisalkar, S.G.; Ramakrishna, S.

    2012-02-15

    Electrospun copper based composite nanofibers were synthesized using the copper acetate/polyvinyl alcohol/water solution as starting material. Synthesized composite nanofibers were sintered at 500 Degree-Sign C to obtain CuO nanofibers. XRD, FTIR and XPS techniques were used to confirm the presence of pure CuO nanostructures. The effect of annealing cycle on the crystalline structure of the CuO nanofibers was analyzed and observed that the decrease in crystallite size with an increase in the dwelling time improved the orientation of the CuO crystallite. The blue-shift in the band-gap energies of CuO nanofibers was observed as a result of quantum confinement from bulk CuO (1.2 eV) to one dimensional (1D) nanostructures ({approx}1.746 eV). The catalytic activity of the CuO fibers for the degradation of methyl orange was carried out and as a blocking layer in ZnO based DSSC was fabricated and observed a {approx}25% increase in the current density. - Graphical abstract: The study on the suitability of highly crystalline CuO nanofibers as the blocking layer in ZnO based DSSC was demonstrated and fabricated with possible energy applications. Highlights: Black-Right-Pointing-Pointer CuO nanofibers were successfully synthesized by using electrospinning technique. Black-Right-Pointing-Pointer The effect of the dwelling time of the annealing cycle for the formation of the crystallite CuO nanofibers was analyzed. Black-Right-Pointing-Pointer A 25% increase in the current density was observed with the application of CuO as blocking layer.

  12. Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The AlxSc1-xN alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt AlxSc1-xN alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt AlxSc1-xN alloys enable high quality epitaxial rocksalt metal/AlxSc1-xN superlattices with a wide range of accessible metamaterials properties.

  13. Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The AlxSc1-xN alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt AlxSc1-xN alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt AlxSc1-xN alloys enable high quality epitaxial rocksalt metal/AlxSc1-xN superlattices with a wide range of accessible metamaterials properties.

  14. A 24-h forecast of solar irradiance using artificial neural network: Application for performance prediction of a grid-connected PV plant at Trieste, Italy

    SciTech Connect (OSTI)

    Mellit, Adel; Pavan, Alessandro Massi

    2010-05-15

    Forecasting of solar irradiance is in general significant for planning the operations of power plants which convert renewable energies into electricity. In particular, the possibility to predict the solar irradiance (up to 24 h or even more) can became - with reference to the Grid Connected Photovoltaic Plants (GCPV) - fundamental in making power dispatching plans and - with reference to stand alone and hybrid systems - also a useful reference for improving the control algorithms of charge controllers. In this paper, a practical method for solar irradiance forecast using artificial neural network (ANN) is presented. The proposed Multilayer Perceptron MLP-model makes it possible to forecast the solar irradiance on a base of 24 h using the present values of the mean daily solar irradiance and air temperature. An experimental database of solar irradiance and air temperature data (from July 1st 2008 to May 23rd 2009 and from November 23rd 2009 to January 24th 2010) has been used. The database has been collected in Trieste (latitude 45 40'N, longitude 13 46'E), Italy. In order to check the generalization capability of the MLP-forecaster, a K-fold cross-validation was carried out. The results indicate that the proposed model performs well, while the correlation coefficient is in the range 98-99% for sunny days and 94-96% for cloudy days. As an application, the comparison between the forecasted one and the energy produced by the GCPV plant installed on the rooftop of the municipality of Trieste shows the goodness of the proposed model. (author)

  15. Artificial Photosynthesis II - Joint Center for Artificial Photosynthe...

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

    evolution; (3) Membranes: finding the right material and fabrication routes for the multifunctional membrane that is the key ingredient in a photoelectrochemical cell; and...

  16. Nanoscale, multidimensional artificial magnet created

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

    2003 Nisoli began designing dedicated topologies based on a new level of frustration New Journal of Physics 15 (4), 045009, 20013. Indeed frustration is an essential...

  17. Mapping suitability areas for concentrated solar power plants...

    Office of Scientific and Technical Information (OSTI)

    Our approach uses digital elevation model derived from NASA s Shuttle Radar Topographic ... Subject: 14 SOLAR ENERGY; 29 ENERGY PLANNING, POLICY, AND ECONOMY concentrated solar ...

  18. Project Profile: Deep Eutectic Salt Formulations Suitable as...

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

    J.W. Raade and D. Padowitz, "Development of Molten Salt Heat Transfer Fluid with Low Melting Point and High Thermal Stability," Journal of Solar Energy Engineering, Vol. 133, No. ...

  19. Carbon nanostructures on silicon substrates suitable for nanolithography

    SciTech Connect (OSTI)

    Abdi, Y.; Mohajerzadeh, S.; Hoseinzadegan, H.; Koohsorkhi, J.

    2006-01-30

    We report the application of vertically grown carbon nanotubes (CNTs) for submicron and nanolithography. The growth of CNTs is performed on silicon substrates using a nickel-seeded plasma-enhanced chemical vapor deposition method at a temperature of 650 deg. C and with a mixture of C{sub 2}H{sub 2} and H{sub 2}. The grown CNTs are encapsulated by a titanium-dioxide film and then mechanically polished to expose the buried nanotubes, and a plasma ashing step finalizes the process. The emission of electrons from the encapsulated nanotubes is used to write patterns on a resist-coated substrate placed opposite to the main CNT holding one. Scanning electron microscope has been used to investigate the nanotubes and the formation of nano-metric lines. Also a novel approach is presented to create isolated nanotubes from a previously patterned cluster growth.

  20. Substrates suitable for deposition of superconducting thin films

    DOE Patents [OSTI]

    Feenstra, Roeland; Boatner, Lynn A.

    1993-01-01

    A superconducting system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

  1. Cobalt doped lanthanum chromite material suitable for high temperature use

    DOE Patents [OSTI]

    Ruka, R.J.

    1986-12-23

    A high temperature, solid electrolyte electrochemical cell, subject to thermal cycling temperatures of between about 25 C and about 1,200 C, capable of electronic interconnection to at least one other electrochemical cell and capable of operating in an environment containing oxygen and a fuel, is made; where the cell has a first and second electrode with solid electrolyte between them, where an improved interconnect material is applied along a portion of a supporting electrode; where the interconnect is made of a chemically modified lanthanum chromite, containing cobalt as the important additive, which interconnect allows for adjustment of the thermal expansion of the interconnect material to more nearly match that of other cell components, such as zirconia electrolyte, and is stable in oxygen containing atmospheres such as air and in fuel environments. 2 figs.

  2. New Metallization Technique Suitable for 6-MW Pilot Production...

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

    This report describes CaliSolar's work as a Photovoltaic Technology Incubator awardee within the U.S. Department of Energy's Solar Energy Technologies Program. The term of this ...

  3. Validity of ELTB Equation for Suitable Description of BEC

    SciTech Connect (OSTI)

    Kim, Dooyoung; Kim, Jinguanghao; Yoon, Jin-Hee

    2005-10-17

    The Bose-Einstein condensation (BEC) has been found for various alkali-metal gases such as 7Li, 87Rb, Na, and H. For the description of atoms in this condensate state, the Gross-Pitaevskii (GP) equation has been widely used. However, the GP equation contains the nonlinear term, which makes this equation hard to solve. Therefore, physical quantities are usually obtained numerically, and sometimes it is difficult to extract a physical meaning from the calculated results. The nuclear theory group at Purdue University in the U.S. developed a new simple equation, the equivalent linear two-body (ELTB) equation, using the hyper-radius coordinates and tested it for one-dimensional BEC system. Their results are consistent with the numerical values from the GP equation within 4.5%.We test the validity of the ELTB equation for three-dimensional BEC system by calculating the energies per particle and the wave functions for 87Rb gas and for 7Li gas. We use the quantum-mechanical variational method for the BEC energy. Our result for 87Rb gas agrees with a numerical calculation based on the GP equation, with a relative error of 12% over a wide range of N from 100 to 10,000. The relative distances between particles for 7Li gas are consistent within a relative error of 17% for N {<=} 1300. The relatively simple form of the ELTB equation, compared with the GP equation, enables us to treat the N-body system easily and efficiently. We conclude that the ELTB equation is a powerful equation for describing BEC system because it is easy to treat.

  4. Subtilisin variants suitable for hydrolysis and synthesis in organic media

    DOE Patents [OSTI]

    Arnold, Frances H.; Chen, Keqin

    1994-05-31

    In accordance with the present invention, there are provided novel, modified subtilisin enzyme(s) having improved catalytic activity and/or stability in organic media.

  5. Triple inverter pierce oscillator circuit suitable for CMOS

    DOE Patents [OSTI]

    Wessendorf; Kurt O.

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  6. Process Reform, Security and Suitability- December 17, 2008

    Broader source: Energy.gov [DOE]

    This is to report on the progress made to improve the timeliness and effectiveness of our hiring and clearing decisions and the specific plan to reform the process further, in accordance with our initial proposals made in April ofthis year.

  7. New Metallization Technique Suitable for 6-MW Pilot Production...

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

    ... PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dr. Kamel Ounadjela Dr. Alain Blosse 5d. PROJECT NUMBER NRELSR-520-48591 5e. TASK NUMBER PV10.2010 5f. WORK UNIT NUMBER 7. PERFORMING ...

  8. An Industrial Membrane System Suitable for Distributed Used Oil...

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

    such as thermal and chemical stability, including waste oil re-refining, coal tar oil clean-up, and FCC slurry upgrading. * In parallel, use these applications and know-how ...

  9. AMO Requests Technical Topics Suitable for a Manufacturing Innovation Institute

    Broader source: Energy.gov [DOE]

    The Advanced Manufacturing Office (AMO) seeks information on mid-Technology Readiness Level (TRL) research and development (R&D) needs, market challenges, supply chain challenges, and shared facility needs to address challenges associated with clean energy manufacturing.

  10. Recombinant hosts suitable for simultaneous saccharification and fermentation

    DOE Patents [OSTI]

    Ingram, Lonnie O'Neal; Zhou, Shengde

    2007-06-05

    The invention provides recombinant host cells containing at least one heterologous polynucleotide encoding a polysaccharase under the transcriptional control of a surrogate promoter capable of increasing the expression of the polysaccharase. In addition, the invention further provides such hosts with genes encoding secretory protein/s to facilitate the secretion of the expressed polysaccharase. Preferred hosts of the invention are ethanologenic and capable of carrying out simultaneous saccharification fermentation resulting in the production of ethanol from complex cellulose substrates.

  11. Multilayer capacitor suitable for substrate integration and multimegahertz filtering

    DOE Patents [OSTI]

    Ngo, Khai D. T.

    1990-01-01

    A multilayer capacitor comprises stacked, spaced-apart electrodes of sheet form, dielectric layers between the electrodes, and first and second groups of spaced-apart conductive vias extending transversely of the sheet-form electrodes and through aligned holes in the dielectric layers. Alternate electrodes are instantaneously positive, and the remaining electrodes are instantaneously negative. Each via of the first group is electrically connected to the positive electrodes and passes insulatingly through the negative electrodes. Similarly, each via of the second group is electrically connected to the negative electrodes and passes insulatingly through the positive electrodes. Each via has, in the plane of the electrodes, a cross-sectional form in the shape of an elongated rib of greater length than width. The elongated ribs of the first group are disposed in a first plurality of rows with their lengths in spaced-apart, aligned relationship, and the ribs of the second group are disposed in a second plurality of rows with their lengths in spaced-apart, aligned relationship. The first plurality of rows is disposed substantially orthogonally with respect to the second plurality of rows.

  12. Composition suitable for decontaminating a porous surface contaminated with cesium

    DOE Patents [OSTI]

    Kaminski, Michael D.; Finck, Martha R.; Mertz, Carol J.

    2010-06-15

    A method of decontaminating porous surfaces contaminated with water soluble radionuclides by contacting the contaminated porous surfaces with an ionic solution capable of solubilizing radionuclides present in the porous surfaces followed by contacting the solubilized radionuclides with a gel containing a radionuclide chelator to bind the radionuclides to the gel, and physically removing the gel from the porous surfaces. A dry mix is also disclosed of a cross-linked ionic polymer salt, a linear ionic polymer salt, a radionuclide chelator, and a gel formation controller present in the range of from 0% to about 40% by weight of the dry mix, wherein the ionic polymer salts are granular and the non cross-linked ionic polymer salt is present as a minor constituent.

  13. Intelligent Unmanned Vehicle Systems Suitable For Individual or Cooperative Missions

    SciTech Connect (OSTI)

    Matthew O. Anderson; Mark D. McKay; Derek C. Wadsworth

    2007-04-01

    The Department of Energys Idaho National Laboratory (INL) has been researching autonomous unmanned vehicle systems for the past several years. Areas of research have included unmanned ground and aerial vehicles used for hazardous and remote operations as well as teamed together for advanced payloads and mission execution. Areas of application include aerial particulate sampling, cooperative remote radiological sampling, and persistent surveillance including real-time mosaic and geo-referenced imagery in addition to high resolution still imagery. Both fixed-wing and rotary airframes are used possessing capabilities spanning remote control to fully autonomous operation. Patented INL-developed auto steering technology is taken advantage of to provide autonomous parallel path swathing with either manned or unmanned ground vehicles. Aerial look-ahead imagery is utilized to provide a common operating picture for the ground and air vehicle during cooperative missions. This paper will discuss the various robotic vehicles, including sensor integration, used to achieve these missions and anticipated cost and labor savings.

  14. Cobalt doped lanthanum chromite material suitable for high temperature use

    DOE Patents [OSTI]

    Ruka, Roswell J.

    1986-01-01

    A high temperature, solid electrolyte electrochemical cell, subject to thermal cycling temperatures of between about 25.degree. C. and about 1200.degree. C., capable of electronic interconnection to at least one other electrochemical cell and capable of operating in an environment containing oxygen and a fuel, is made; where the cell has a first and second electrode with solid electrolyte between them, where an improved interconnect material is applied along a portion of a supporting electrode; where the interconnect is made of a chemically modified lanthanum chromite, containing cobalt as the important additive, which interconnect allows for adjustment of the thermal expansion of the interconnect material to more nearly match that of other cell components, such as zirconia electrolyte, and is stable in oxygen containing atmospheres such as air and in fuel environments.

  15. Site Suitability and Hazard Assessment Guide for Small Modular Reactors

    SciTech Connect (OSTI)

    Wayne Moe

    2013-10-01

    Commercial nuclear reactor projects in the U.S. have traditionally employed large light water reactors (LWR) to generate regional supplies of electricity. Although large LWRs have consistently dominated commercial nuclear markets both domestically and abroad, the concept of small modular reactors (SMRs) capable of producing between 30 MW(t) and 900 MW(t) to generating steam for electricity is not new. Nor is the idea of locating small nuclear reactors in close proximity to and in physical connection with industrial processes to provide a long-term source of thermal energy. Growing problems associated continued use of fossil fuels and enhancements in efficiency and safety because of recent advancements in reactor technology suggest that the likelihood of near-term SMR technology(s) deployment at multiple locations within the United States is growing. Many different types of SMR technology are viable for siting in the domestic commercial energy market. However, the potential application of a particular proprietary SMR design will vary according to the target heat end-use application and the site upon which it is proposed to be located. Reactor heat applications most commonly referenced in connection with the SMR market include electric power production, district heating, desalinization, and the supply of thermal energy to various processes that require high temperature over long time periods, or a combination thereof. Indeed, the modular construction, reliability and long operational life purported to be associated with some SMR concepts now being discussed may offer flexibility and benefits no other technology can offer. Effective siting is one of the many early challenges that face a proposed SMR installation project. Site-specific factors dealing with support to facility construction and operation, risks to the plant and the surrounding area, and the consequences subsequent to those risks must be fully identified, analyzed, and possibly mitigated before a license will be granted to construct and operate a nuclear facility. Examples of significant site-related concerns include area geotechnical and geological hazard properties, local climatology and meteorology, water resource availability, the vulnerability of surrounding populations and the environmental to adverse effects in the unlikely event of radionuclide release, the socioeconomic impacts of SMR plant installation and the effects it has on aesthetics, proximity to energy use customers, the topography and area infrastructure that affect plant constructability and security, and concerns related to the transport, installation, operation and decommissioning of major plant components.

  16. Nuclear Energy Infrastructure Database Fitness and Suitability Review

    SciTech Connect (OSTI)

    Heidrich, Brenden

    2015-03-01

    In 2014, the Deputy Assistant Secretary for Science and Technology Innovation (NE-4) initiated the Nuclear Energy-Infrastructure Management Project by tasking the Nuclear Science User Facilities (NSUF) to create a searchable and interactive database of all pertinent NE supported or related infrastructure. This database will be used for analyses to establish needs, redundancies, efficiencies, distributions, etc. in order to best understand the utility of NE’s infrastructure and inform the content of the infrastructure calls. The NSUF developed the database by utilizing data and policy direction from a wide variety of reports from the Department of Energy, the National Research Council, the International Atomic Energy Agency and various other federal and civilian resources. The NEID contains data on 802 R&D instruments housed in 377 facilities at 84 institutions in the US and abroad. A Database Review Panel (DRP) was formed to review and provide advice on the development, implementation and utilization of the NEID. The panel is comprised of five members with expertise in nuclear energy-associated research. It was intended that they represent the major constituencies associated with nuclear energy research: academia, industry, research reactor, national laboratory, and Department of Energy program management. The Nuclear Energy Infrastructure Database Review Panel concludes that the NSUF has succeeded in creating a capability and infrastructure database that identifies and documents the major nuclear energy research and development capabilities across the DOE complex. The effort to maintain and expand the database will be ongoing. Detailed information on many facilities must be gathered from associated institutions added to complete the database. The data must be validated and kept current to capture facility and instrumentation status as well as to cover new acquisitions and retirements.

  17. Electromechanical battery design suitable for back-up power applications

    DOE Patents [OSTI]

    Post, Richard F.

    2002-01-01

    The windings that couple energy into and out of the rotor of an electro-mechanical battery are modified. The normal stator windings of the generator/motor have been replaced by two orthogonal sets of windings. Because of their orthogonality, they are decoupled from each other electrically, though each can receive (or deliver) power flows from the rotating field produced by the array of permanent magnets. Due to the orthogonal design of the stator windings and the high mechanical inertia of the flywheel rotor, the resulting power delivered to the computer system is completely insensitive to any and all electrical transients and variabilities of the power from the main power source. This insensitivity includes complete failure for a period determined only by the amount of stored kinetic energy in the E-M battery modules that are supplied. Furthermore there is no need whatsoever for fast-acting, fractional-cycle switches, such as are employed in conventional systems, and which are complicated to implement.

  18. High elastic modulus polymer electrolytes suitable for preventing...

    Office of Scientific and Technical Information (OSTI)

    Authors: Mullin, Scott ; Panday, Ashoutosh ; Balsara, Nitash Pervez ; Singh, Mohit ; Eitouni, Hany Basam ; Gomez, Enrique Daniel Publication Date: 2014-04-22 OSTI Identifier: ...

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

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

    With the recent advance of "spintronics" - an area of science and technology which proposes to use the spin of electrons to store and process information instead of their charge as ...

  20. Use of graphitized carbon beads for gas liquid chromatography

    DOE Patents [OSTI]

    Talmi, Yair; Pollock, Charles B.

    1976-01-01

    Carbonized resin microspheroids are used as a column packing in gas-solid chromatography and as a support in gas-liquid chromatography.

  1. Non-graphite crucible for high temperature applications

    DOE Patents [OSTI]

    Holcombe, Cressie E.; Pfeiler, William A.

    1994-01-01

    A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material.

  2. Non-graphite crucible for high temperature applications

    DOE Patents [OSTI]

    Holcombe, Cressie E.; Pfeiler, William A.

    1996-01-01

    A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. The multi-piece crucible is contained in a thermal can assembly of a high temperature induction furnace during a high temperature melt-casting operation. One embodiment of the multi-piece crucible comprises a tubular member having a vertical slot filled with a ceramic sealing material to provide expansion of the tubular member without cracking during the high temperature melt-casting operation.

  3. Non-graphite crucible for high temperature applications

    DOE Patents [OSTI]

    Holcombe, C.E.; Pfeiler, W.A.

    1994-08-02

    A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. 6 figs.

  4. Electron Charged Graphite-based Hydrogen Storage Material

    SciTech Connect (OSTI)

    Dr. Chinbay Q. Fan R&D Manager Office of Technology and Innovations Phone: 847 768 0812

    2012-03-14

    The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage methods; however, it could be high for the battery mode.

  5. Graphite and its Hidden Superconductivity | Stanford Synchrotron Radiation

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

    Graphics Graphics The Visual Media Department consists of a team of graphic artists, photographers and visual librarians working together to provide a wide variety of visual media for the Department of Energy. Graphics Offices Forrestal: Room BH-071, (202) 586-2732 Germantown: Room E-065, (301) 903-5165 Graphics@hq.doe.gov If you have need of our services and you are located at either of the Forrestal Building or Germantown complexes, submit a completed Request for Print, Mail and Visual Media

  6. First Direct Evidence of Dirac Fermions in Graphite

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

    (like photons traveling in free space at the speed of light) that exhibit a linear dispersion relationship given by the equation E vk, where the wavenumber (k) represents...

  7. Carbon or Graphite Foam Heating Element for Regulating Engine Fluids -

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

    R&D Carbon Storage R&D Carbon dioxide storage in geologic formations includes oil and gas reservoirs, unmineable coal seams, and deep saline reservoirs. These are structures that have stored crude oil, natural gas, brine and CO2 over millions of years. The primary goal of our carbon storage research is to understand the behavior of CO2 when stored in geologic formations. For example, studies are being conducted to determine the extent to which the CO2 moves within the geologic formation,

  8. Manufacturing Challenges for BOP and Graphite Stack Components

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

    ... heat treatment CONFIDENTIAL | 12 Primary Market Areas EDM EDM Glass Glass Semiconductor Semiconductor IndustrialBiomedical Products IndustrialBiomedical Products Optics Optics

  9. Low Cost SiOx-Graphite and Olivine Materials

    Broader source: Energy.gov [DOE]

    2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

  10. First Direct Evidence of Dirac Fermions in Graphite

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

    and Y. Kopelevich (Universidade Estadual de Campinas, Brazil). Research funding: National Science Foundation; U.S. Department of Energy, Office of Basic Energy Sciences (BES); and...

  11. Pyrotek Graphitization Facility Expansion Project | Department of Energy

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

    Federal Energy Management Program (FEMP) provides acquisition guidance for air-cooled ice machines, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law. FEMP's acquisition guidance and associated ENERGY STAR efficiency requirements for

  12. High order reflectivity of graphite (HOPG) crystals for x ray...

    Office of Scientific and Technical Information (OSTI)

    In second order the integrated reflectivity decreases from 1.3 mrad at 12.6 keV to ... Country of Publication: United States Language: English Subject: 70 PLASMA PHYSICS AND FUSION; ...

  13. First Direct Evidence of Dirac Fermions in Graphite

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

    one atomic layer thick-has largely been driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of...

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

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

    11 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon arravt012esmcchesney2011p.pdf More Documents & ...

  15. Non-graphite crucible for high temperature applications

    DOE Patents [OSTI]

    Holcombe, C.E.; Pfeiler, W.A.

    1996-01-09

    A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. The multi-piece crucible is contained in a thermal can assembly of a high temperature induction furnace during a high temperature melt-casting operation. One embodiment of the multi-piece crucible comprises a tubular member having a vertical slot filled with a ceramic sealing material to provide expansion of the tubular member without cracking during the high temperature melt-casting operation. 9 figs.

  16. Recapturing Graphite-Based Fuel Element Technology for Nuclear...

    Office of Scientific and Technical Information (OSTI)

    Authors: Trammell, Michael P 1 ; Jolly, Brian C 1 ; Miller, James Henry 1 ; Qualls, A L 1 ; Harrison, Thomas J 1 + Show Author Affiliations ORNL Publication Date: ...

  17. Establish and Expand Commercial Production of Graphite Anode Materials for

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

    Turbine Engines | Department of Energy PDF icon erosion-resistant_nanocoatings.pdf More Documents & Publications ITP Nanomanufacturing: Nanomanufacturing Portfolio: Manufacturing Processes and Applications to Accelerate Commercial Use of Nanomaterials, January 2011 2013 R&D 100 Award Winners New and Emerging Technologies

    A Competency and Functional Framework For Cyber Security Workforce Development Documents Available for Download More Documents & Publications Essential Body

  18. Towards bio-silicon interfaces: Formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase

    SciTech Connect (OSTI)

    Retamal, Mara J. Cisternas, Marcelo A.; Seifert, Birger; Volkmann, Ulrich G.; Gutierrez-Maldonado, Sebastian E.; Perez-Acle, Tomas; Busch, Mark; Huber, Patrick

    2014-09-14

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (?25 ) and DPPC (?60 ) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  19. "Artificial" brains, electrical grids, and disease modeling:...

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

    Deputy Principal Associate Director Duncan McBranch will discuss LDRD impacts on border security and the nation's energy grid at 1 p.m. The event is an ideal opportunity...

  20. Mimicking Nature - A Step Towards Artificial Photosynthesis|...

    Office of Science (SC) Website

    The chlorosome, the extremely efficient light harvesting antenna in green photosynthetic bacteria, captures energy from sunlight and funnels it to reaction centers to create fuel ...