Science.gov

Sample records for dispersion type fuel

  1. Dispersion type zirconium matrix fuels fabricated by capillary impregnation method

    NASA Astrophysics Data System (ADS)

    Savchenko, A.; Konovalov, I.; Vatulin, A.; Morozov, A.; Orlov, V.; Uferov, O.; Ershov, S.; Laushkin, A.; Kulakov, G.; Maranchak, S.; Petrova, Z.

    2007-05-01

    Several novel dispersion fuel compositions with a high uranium content fuel (U9Mo, U5Zr5Nb, U3Si) and a zirconium alloy matrix with low melting point (1063-1133 K) have been developed at A.A. Bochvar Institute using a capillary impregnation fabrication method. The capillary impregnation method introduces fuel granules and granules of a zirconium alloy into a fuel element followed by a short-term anneal at a temperature above the melting temperature of alloy. The alloy melts down and under capillary forces moves into the joints between the fuel element components to form metallurgical bonds. The volume ratios between the components are: 55-65% fuel, 10-20% matrix, and 15-30% pores. Fuel elements produced by capillary impregnation method have a high uranium content (9-10 g cm-3) and a high thermal conductivity (18-22 W m-1 K-1), which, when used as PWR or BWR fuels allow the fuel temperature to be lowered to 723-773 K. They also feature porosity to accommodate swelling. The metallurgical fuel-cladding bond makes the fuel elements serviceable in power transients. The primary advantages for PWR, BWR and CANDU use of these fuels elements, would be the high uranium content, low fuel temperature and serviceability under transient conditions. Consideration is given to their applicability in Floating Nuclear Power Plants (FNPP) as well as for the feasibility of burning civil and weapon grade plutonium.

  2. Post-crash fuel dispersal

    SciTech Connect

    Tieszen, S.R.

    1997-03-01

    This paper is a brief overview of work over the last several decades in understanding what occurs to jet fuel stored in aircraft fuel tanks on impact with the ground. Fuel dispersal is discussed in terms of the overall crash dynamics process and impact regimes are identified. In a generic sense, the types of flow regimes which can occur are identified and general descriptions of the processes are given. Examples of engineering level tools, both computational and experimental, which have applicability to analyzing the complex environments are presented. Finally, risk based decision is discussed as a quick means of identifying requirements for development of preventative or mitigation strategies, such as further work on the development of an anti-misting agent.

  3. High density carbon dispersion fuels program

    NASA Technical Reports Server (NTRS)

    Salvesen, R. H.; Lavid, M.

    1980-01-01

    High density carbon dispersion fuels were studied. Promising results were obtained which indicate stable carbon loaded fuels with a minimum of 180,000 Btu per gallon can be made and successfully burned in prototype turbine combustors components. Tests were completed which provide insights to obtaining a better understanding of what types of carbon can be successfully formulated and combusted.

  4. The use of U/sub 3/Si/sub 2/ dispersed in aluminum in plate-type fuel elements for research and test reactors

    SciTech Connect

    Snelgrove, J.L.; Domagala, R.F.; Hofman, G.L.; Wiencek, T.C.; Copeland, G.L.; Hobbs, R.W.; Senn, R.L.

    1987-10-01

    A high-density fuel based on U/sub 3/Si/sub 2/ dispersed in aluminum has been developed and tested for use in converting plate-type research and test reactors from the use of highly enriched uranium to the use of low-enriched uranium. Results of preirradiation testing and the irradiation and postirradiation examination of miniature fuel plates and full-sized fuel elements are summarized. Swelling of the U/sub 3/Si/sub 2/ fuel particles is a linear function of the fission density in the particle to well beyond the fission density achievable in low-enriched fuels. U/sub 3/Si/sub 2/ particle swelling rate is approximately the same as that of the commonly used UAl/sub x/ fuel particle. The presence of minor amounts of U/sub 3/Si or uranium solid solution in the fuel result in greater, but still acceptable, fuel swelling. Blister threshold temperatures are at least as high as those of currently used fuels. An exothermic reaction occurs near the aluminum melting temperature, but the measured energy releases were low enough not to substantially worsen the consequences of an accident. U/sub 3/Si/sub 2/-aluminum dispersion fuel with uranium densities up to at least 4.8 Mg/m/sup 3/ is a suitable LEU fuel for typical plate-type research and test reactors. 42 refs., 28 figs., 7 tabs.

  5. Effect of in-pile degradation of the meat thermal conductivity on the maximum temperature of the plate-type U-Mo dispersion fuels

    SciTech Connect

    Pavel G. Medvedev

    2009-11-01

    Effect of in-pile degradation of thermal conductivity on the maximum temperature of the plate-type research reactor fuels has been assessed using the steady-state heat conduction equation and assuming convection cooling. It was found that due to very low meat thickness, characteristic for this type of fuel, the effect of thermal conductivity degradation on the maximum fuel temperature is minor. For example, the fuel plate featuring 0.635 mm thick meat operating at heat flux of 600 W/cm2 would experience only a 20oC temperature rise if the meat thermal conductivity degrades from 0.8 W/cm-s to 0.3 W/cm-s. While degradation of meat thermal conductivity in dispersion-type U-Mo fuel can be very substantial due to formation of interaction layer between the particles and the matrix, and development of fission gas filled porosity, this simple analysis demonstrates that this phenomenon is unlikely to significantly affect the temperature-based safety margin of the fuel during normal operation.

  6. LMFBR fuel assembly design for HCDA fuel dispersal

    DOEpatents

    Lacko, Robert E.; Tilbrook, Roger W.

    1984-01-01

    A fuel assembly for a liquid metal fast breeder reactor having an upper axial blanket region disposed in a plurality of zones within the fuel assembly. The characterization of a zone is dependent on the height of the axial blanket region with respect to the active fuel region. The net effect of having a plurality of zones is to establish a dispersal flow path for the molten materials resulting during a core meltdown accident. Upward flowing molten material can escape from the core region and/or fuel assembly without solidifying on the surface of fuel rods due to the heat sink represented by blanket region pellets.

  7. Velocity Dispersions Across Bulge Types

    SciTech Connect

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-06-08

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (sigma*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  8. A Study of Fast Reactor Fuel Transmutation in a Candidate Dispersion Fuel Design

    SciTech Connect

    Mark DeHart; Hongbin Zhang; Eric Shaber; Matthew Jesse

    2010-11-01

    Dispersion fuels represent a significant departure from typical ceramic fuels to address swelling and radiation damage in high burnup fuel. Such fuels use a manufacturing process in which fuel particles are encapsulated within a non-fuel matrix. Dispersion fuels have been studied since 1997 as part of an international effort to develop and test very high density fuel types for the Reduced Enrichment for Research and Test Reactors (RERTR) program.[1] The Idaho National Laboratory is performing research in the development of an innovative dispersion fuel concept that will meet the challenges of transuranic (TRU) transmutation by providing an integral fission gas plenum within the fuel itself, to eliminate the swelling that accompanies the irradiation of TRU. In this process, a metal TRU vector produced in a separations process is atomized into solid microspheres. The dispersion fuel process overcoats the microspheres with a mixture of resin and hollow carbon microspheres to create a TRUC. The foam may then be heated and mixed with a metal power (e.g., Zr, Ti, or Si) and resin to form a matrix metal carbide, that may be compacted and extruded into fuel elements. In this paper, we perform reactor physics calculations for a core loaded with the conceptual fuel design. We will assume a “typical” TRU vector and a reference matrix density. We will employ a fuel and core design based on the Advanced Burner Test Reactor (ABTR) design.[2] Using the CSAS6 and TRITON modules of the SCALE system [3] for preliminary scoping studies, we will demonstrate the feasibility of reactor operations. This paper will describe the results of these analyses.

  9. Fission induced swelling of U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Jeong, G. Y.; Park, J. M.; Robinson, A. B.

    2015-10-01

    Fission-induced swelling of U-Mo/Al dispersion fuel meat was measured using microscopy images obtained from post-irradiation examination. The data of reduced-size plate-type test samples and rod-type test samples were employed for this work. A model to predict the meat swelling of U-Mo/Al dispersion fuel was developed. This model is composed of several submodels including a model for interaction layer (IL) growth between U-Mo and Al matrix, a model for IL thickness to IL volume conversion, a correlation for the fission-induced swelling of U-Mo alloy particles, a correlation for the fission-induced swelling of IL, and models of U-Mo and Al consumption by IL growth. The model was validated using full-size plate data that were not included in the model development.

  10. Effect of hydrocarbon fuel type on fuel

    NASA Technical Reports Server (NTRS)

    Wong, E. L.; Bittker, D. A.

    1982-01-01

    A modified jet fuel thermal oxidation tester (JFTOT) procedure was used to evaluate deposit and sediment formation for four pure hydrocarbon fuels over the temperature range 150 to 450 C in 316-stainless-steel heater tubes. Fuel types were a normal alkane, an alkene, a naphthene, and an aromatic. Each fuel exhibited certain distinctive deposit and sediment formation characteristics. The effect of aluminum and 316-stainless-steel heater tube surfaces on deposit formation for the fuel n-decane over the same temperature range was investigated. Results showed that an aluminum surface had lower deposit formation rates at all temperatures investigated. By using a modified JFTOT procedure the thermal stability of four pure hydrocarbon fuels and two practical fuels (Jet A and home heating oil no. 2) was rated on the basis of their breakpoint temperatures. Results indicate that this method could be used to rate thermal stability for a series of fuels.

  11. Fuel cells: principles, types, fuels, and applications.

    PubMed

    Carrette, L; Friedrich, K A; Stimming, U

    2000-12-15

    During the last decade, fuel cells have received enormous attention from research institutions and companies as novel electrical energy conversion systems. In the near future, they will see application in automotive propulsion, distributed power generation, and in low power portable devices (battery replacement). This review gives an introduction into the fundamentals and applications of fuel cells: Firstly, the environmental and social factors promoting fuel cell development are discussed, with an emphasis on the advantages of fuel cells compared to the conventional techniques. Then, the main reactions, which are responsible for the conversion of chemical into electrical energy in fuel cells, are given and the thermodynamic and kinetic fundamentals are stated. The theoretical and real efficiencies of fuel cells are also compared to that of internal combustion engines. Next, the different types of fuel cells and their main components are explained and the related material issues are presented. A section is devoted to fuel generation and storage, which is of paramount importance for the practical aspects of fuel cell use. Finally, attention is given to the integration of the fuel cells into complete systems. PMID:23696319

  12. Highly Dispersed Metal Catalyst for Fuel Cell Electrodes

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will bring industrial catalyst experience to fuel cell research. Specifically, industrial catalysts, such as those used in platforming, utilize precious metal platinum as an active component in a finely dispersed form.

  13. Analytical and experimental investigation of the dispersion process during rapid transients for the aluminum-based nuclear fuel plates

    SciTech Connect

    Georgevich, V.; Taleyarkhan, R.P.; Kim, S.H.; Fuketa, T.; Soyama, K.; Ishijima, K.

    1995-06-01

    A thermally induced fuel-plate dispersion model was developed to analyze for dispersive potential and determine the onset of fuel plate dispersion for aluminum-based research and test reactor fuels. The effect of rapid energy deposition in a fuel plate was simulated. Several data types for aluminum-based fuels tested in the Nuclear Safety Research Reactor (NSRR) facility in Japan and in the Transient Reactor Test (TREAT) facility in Idaho, US, were reviewed. Analyses of experiments show that the onset of fuel dispersion is clearly linked to a sharp rise in the predicted strain rate, which further coincides with the onset of aluminum vaporization. Analysis also shows that aluminum oxidation and exothermal chemical reaction between the fuel and aluminum can significantly affect: the energy deposition characteristics and, therefore dispersion onset connected with aluminum vaporization, and the onset of aluminum vaporization.

  14. Modeling the Influence of Interaction Layer Formation on Thermal Conductivity of U–Mo Dispersion Fuel

    SciTech Connect

    Burkes, Douglas; Casella, Andrew M.; Huber, Tanja K.

    2015-01-01

    The Global Threat Reduction Initiative Program continues to develop existing and new plate- and rod-type research and test reactor fuels with maximum attainable uranium loadings capable of potentially converting a number of the world’s remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of an even higher density fuel type consisting of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel plate and can be influenced by interaction layer formation between the fuel and matrix, porosity that forms during fabrication of the fuel plates, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation and conductivity, fuel particle size, and volume fraction of fuel dispersed in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be important in determining the overall conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the fuel particle distribution by minimizing interaction layer formation and preserving the higher thermal conductivity matrix.

  15. Fueling type III secretion

    PubMed Central

    Lee, Pei-Chung

    2015-01-01

    Type III secretion systems are complex nanomachines that export proteins from the bacterial cytoplasm across the cell envelope in a single step. They are at the core of the machinery used to assemble the bacterial flagellum, and the needle complex many Gram-negative pathogens use to inject effector proteins into host cells and cause disease. Several models have been put forward to explain how this export is energized, and the mechanism has been the subject of considerable debate. Here we present an overview of these models and discuss their relative merits. Recent evidence suggests that the proton motive force is the primary energy source for type III secretion, although contribution from refolding of secreted proteins has not been ruled out. The mechanism, by which the proton motive force is converted to protein export, remains enigmatic. PMID:25701111

  16. Fuel dispersal modeling for aircraft-runway impact scenarios

    SciTech Connect

    Tieszen, S.R.

    1995-11-01

    A fuel dispersal model for C-141 transport accidents was developed for the Defense Nuclear Agency`s Fuel Fire Technology Base Program to support Weapon System Safety Assessments. The spectrum of accidents resulting from aircraft impact on a runway was divided into three fuel dispersal regimes: low, intermediate, and high-velocity impact. Sufficient data existed in the accident, crash test, and fuel-filled bomb literature to support development of a qualitative framework for dispersal models, but not quantitative models for all regimes. Therefore, a test series at intermediate scale was conducted to generate data on which to base the model for the high-velocity regime. Tests were conducted over an impact velocity range from 12 m/s to 91 m/s and angles of impact from 22.5{degrees} to 67.5{degrees}. Dependent variables were area covered by dispersed fuel, amount of mass in that area, and location of the area relative to the impact line. Test results showed that no liquid pooling occurred for impact velocities greater than 61 m/s, independent of the angle of impact. Some pooling did occur at lower velocities, but in no test was the liquid-layer thickness greater than 5.25 mm.

  17. Fabrication of oxide dispersion strengthened ferritic clad fuel pins

    SciTech Connect

    Zirker, L.R. ); Bottcher, J.H. ); Shikakura, S. ); Tsai, C.L. . Dept. of Welding Engineering); Hamilton, M.L. )

    1991-01-01

    A resistance butt welding procedure was developed and qualified for joining ferritic fuel pin cladding to end caps. The cladding are INCO MA957 and PNC ODS lots 63DSA and 1DK1, ferritic stainless steels strengthened by oxide dispersion, while the end caps are HT9 a martensitic stainless steel. With adequate parameter control the weld is formed without a residual melt phase and its strength approaches that of the cladding. This welding process required a new design for fuel pin end cap and weld joint. Summaries of the development, characterization, and fabrication processes are given for these fuel pins. 13 refs., 6 figs., 1 tab.

  18. IMPROVED TYPE OF FUEL ELEMENT

    DOEpatents

    Monson, H.O.

    1961-01-24

    A radiator-type fuel block assembly is described. It has a hexagonal body of neutron fissionable material having a plurality of longitudinal equal- spaced coolant channels therein aligned in rows parallel to each face of the hexagonal body. Each of these coolant channels is hexagonally shaped with the corners rounded and enlarged and the assembly has a maximum temperature isothermal line around each channel which is approximately straight and equidistant between adjacent channels.

  19. Development of a Monolithic Research Reactor Fuel Type at Argonne National Laboratory

    SciTech Connect

    Clark, C.R.; Briggs, R.J.

    2004-10-06

    The Reduced Enrichment for Research and Test Reactors (RERTR) program has been tasked with the conversion of research reactors from highly enriched to low-enriched uranium (LEU). To convert several high power reactors, monolithic fuel, a new fuel type, is being developed. This fuel type replaces the standard fuel dispersion with a fuel alloy foil, which allows for fuel densities far in excess of that found in dispersion fuel. The single-piece fuel foil also contains a significantly lower interface area between the fuel and the aluminum in the plate than the standard fuel type, limiting the amount of detrimental fuel-aluminum interaction that can occur. Implementation of monolithic fuel is dependant on the development of a suitable fabrication method as traditional roll-bonding techniques are inadequate.

  20. Shock-Dispersed-Fuel Charges: Combustion in Chambers and Tunnels

    SciTech Connect

    Neuwald, P; Reichenbach, H; Kuhl, A L

    2003-04-22

    In previous studies we have investigated after-burning effects of a fuel-rich explosive (TNT). In that case the detonation only releases about 30% of the available energy, but generates a hot cloud of fuel that can burn in the ambient air, thus evoking an additional energy release that is distributed in space and time. The current series of small-scale experiments can be looked upon as a natural generalization of this mechanism: a booster charge disperses a (non-explosive) fuel, provides mixing with air and, by means of the hot detonation products, the energy to ignite the fuel. The current version of our miniature Shock-Dispersed-Fuel (SDF) charges consists of a spherical booster charge of 0.5 g PETN, embedded in a paper cylinder of approximately 2.2 cm, which is filled with powdered fuel compositions. The main compositions studied up to now contain aluminum flakes, hydrocarbon powders like polyethylene or hexosen (sucrose) and/or carbon particles. These charges were studied in four different chambers: two cylindrical vessels of 6.6-1 and 40.5-1 volume with a height-to-diameter ratio of approximately 1, a rectangular chamber of 41 (10.5 x 10.5 x 38.6 cm) and a 299.6 cm long tunnel model with a cross section of 8 x 8 cm (volume 19.21) closed at both ends.

  1. Combustion of Shock-Dispersed Fuels in a Chamber

    SciTech Connect

    Neuwald, P; Reichenbach, H; Kuhl, A L

    2003-04-23

    In previous studies we have investigated after-burning effects of a fuel-rich explosive (TNT). In that case the detonation only releases about 30 % of the available energy, but generates a hot cloud of fuel that can burn in the ambient air, thus evoking an additional energy release that is distributed in space and time. The current series of small-scale experiments can be looked upon as a natural generalization of this mechanism: a booster charge disperses a (non-explosive) fuel, provides mixing with air and - by means of the hot detonation products - energy to ignite the fuel. The current version of our miniature Shock-Dispersed-Fuel (SDF) charges consists of a spherical booster charge of 0.5 g PETN, embedded in a paper cylinder of approximately 2.2 cm3, which is filled with powdered fuel compositions. The main compositions studied up to now contain aluminum powder, hydrocarbon powders like polyethylene or sucrose and/or carbon particles. These charges were studied in three different chambers of 4-1, 6.6-1 and 40.5-1 volume. In general, the booster charge was sufficient to initiate burning of the fuel. This modifies the pressure signatures measured with a number of wall gages and increases the quasi-static overpressure level obtained in the chambers. On the one hand the time-scale and the yield of the pressure rise depend on the fuel and its characteristics. On the other hand they also depend on the flow dynamics in the chamber, which is dominated by shock reverberations, and thus on the chamber geometry and volume. The paper gives a survey of the experimental results and discusses the possible influences of some basic parameters.

  2. Pore growth in U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Jeong, G. Y.; Sohn, D.-S.; Jamison, L. M.

    2016-09-01

    U-Mo/Al dispersion fuel is currently under development in the DOE's Material Management and Minimization program to convert HEU-fueled research reactors to LEU-fueled reactors. In some demanding conditions in high-power and high-performance reactors, large pores form in the interaction layers between the U-Mo fuel particles and the Al matrix, which pose a potential to cause fuel failure. In this study, comprehension of the formation and growth of these pores was explored. As a product, a model to predict pore growth and porosity increase was developed. The model includes three major topics: fission gas release from the U-Mo and the IL to the pores, stress evolution in the fuel meat, and the effect of amorphous IL growth. Well-characterized in-pile data from reduced-size plates were used to fit the model parameters. A data set from full-sized plates, independent and distinctively different from those used to fit the model parameters, was used to examine the accuracy of the model. The model showed fair agreement with the measured data. The model suggested that the growth of the IL has a critical effect on pore growth, as both its material properties and energetics are favorable to pore formation. Therefore, one area of the current effort, focused on suppressing IL growth, appears to be on the right track to improve the performance of this fuel.

  3. Design and fabrication of high density uranium dispersion fuels

    SciTech Connect

    Trybus, C.L.; Meyer, M.K.; Clark, C.R.; Wlencek, T.C.; McGann, D.J.

    1997-11-01

    Twelve different uranium alloys and compounds with uranium densities greater than 13.8 g/cc were fabricated into fuel plates. Sixty-four experimental fuel plates, referred to as microplates, with overall dimensions of 76.2 mm x 22.2 mm x 1.3 mm and elliptical fuel zone of nominal dimensions of 51 mm x 9.5 mm, began irradiation in the Advanced Test Reactor on August 23, 1997. The fuel test matrix consists of machined or comminuted (compositions are in weight %) U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U6Mo-0.6 Ru, U-10Mo-0.05Sn, U{sub 2}Mo and U{sub 3}Si{sub 2} (as a control). The low enriched ({sup 235}U < 20%) fuel materials were cast, powdered, mixed with aluminum dispersant at a volume ratio of 1:3, compacted and hot rolled to form the microplates. Spherical atomized powders of two fuels, U-10Mo and U{sub 3}Si{sub 2}, were utilized to make microplates and included in the irradiation test as well. The experimental design and fabrication steps employed in the selection and production of the fueled microplates is discussed.

  4. Main results of the development of dispersion type IMF at A.A. Bochvar Institute

    NASA Astrophysics Data System (ADS)

    Savchenko, A. M.; Vatulin, A. V.; Glagovsky, E. M.; Konovalov, I. I.; Morozov, A. V.; Kozlov, A. V.; Ershov, S. A.; Mishunin, V. A.; Kulakov, G. V.; Sorokin, V. I.; Simonov, A. P.; Petrova, Z. N.; Fedotov, V. V.

    2010-01-01

    At A.A. Bochvar Institute a novel conception of IMF to burn civil and weapon's grade Pu is currently accepted. It consists in the fact, that instead of using pelletized IMF, that features low serviceability and dust forming route of fuel element fabrication, the usage is made of dispersion type fuel element with aluminium or zirconium matrices. Dispersion fuels feature a high irradiation resistance and reliability; they can consequently reach high burnups and be serviceable under transient conditions. Three basic fuel element versions are under development in VNIINM for both thermal and fast reactors. The first version is a fuel element with a heterogeneous arrangement of fuel (PuO 2 or YSZ granules) within an Al or Zr matrix. The second version of a fuel element has a heat conducting Al or Zr alloy matrix and an isolated arrangement of PuO 2 in a fuel minielement more fully meets the 'Rock Fuel' requirements. According to the third version a porous meat of zirconium metallurgically bonded to a fuel cladding is formed through which a PuO 2 powder is introduced. All the versions are technologically simple to fabricate and require minimal quantities of process operations related to treating MA and Pu. Preliminary in-pile tests of IMF prototypes are presented.

  5. Mechanical analysis of UMo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Jeong, Gwan Yoon; Kim, Yeon Soo; Sohn, Dong-Seong

    2015-11-01

    Deformation of fuel particles and mass transfer from the transverse end of fuel meat toward the meat center was observed. This caused plate thickness peaking at a location between the meat edge and the meat center. The underlying mechanism for this fuel volume transport is believed to be fission induced creep of the U-Mo/Al meat. Fuel meat swelling was measured using optical microscopy images of the cross sections of the irradiated test plates. The time-dependent meat swelling was modeled for use in numerical simulation. A distinctive discrepancy between the predicted and measured meat thickness was found at the meat ends, which was assumed to be due to creep-induced mass relocation from the meat end to the meat center region that was not considered in the meat swelling model. ABAQUS FEA simulation was performed to reproduce the observed phenomenon at the meat ends. Through the simulation, we obtained the effective creep rate constants for the interaction layers (IL) and aluminum matrix. In addition, we obtained the corresponding stress and strain analysis results that can be used to understand mechanical behavior of U-Mo/Al dispersion fuel.

  6. Unirradiated characteristics of U-Si alloys as dispersed-phase fuels

    SciTech Connect

    Domagala, R.F.; Wiencek, T.C.

    1987-06-01

    To satisfy the power demands of many research reactors, a new LEU fuel with a high density and U content was needed. Any fuel must be compatible with Al and its alloys so that it may be fabricable as a dispersed-phase in Al alloy and Al matrix plate-type elements following, as nearly as possible, established commercial manufacturing techniques. U-Si and U-Si-Al alloys at or near the composition of U/sub 3/Si were immediately attractive because of work documented by the Canadians. 8 refs., 2 figs.

  7. Thermal conductivity modeling of U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Cho, Byoung Jin; Sohn, Dong-Seong; Park, Jong Man

    2015-11-01

    A dataset for the thermal conductivity of U-Mo/Al dispersion fuel made available by KAERI was reanalyzed. Using this dataset, an analytical model was obtained by expanding the Bruggeman model. The newly developed model incorporates thermal resistances at the interface between the U-Mo particles and the Al matrix and the defects within the Al matrix (grain boundaries, cracks, and dislocations). The interfacial resistances are expressed as functions of U-Mo particle size and Al grain size obtained empirically by fitting to measured data from KAERI. The model was then validated against an independently measured dataset from ANL.

  8. Irradiation testing of high density uranium alloy dispersion fuels

    SciTech Connect

    Hayes, S.L.; Trybus, C.L.; Meyer, M.K.

    1997-10-01

    Two irradiation test vehicles have been designed, fabricated, and inserted into the Advanced Test Reactor in Idaho. Irradiation of these experiments began in August 1997. These irradiation tests were designed to obtain irradiation performance information on a variety of potential new, high-density dispersion fuels. Each of the two irradiation vehicles contains 32 microplates. Each microplate is aluminum clad, having an aluminum matrix phase and containing one of the following compositions as the fuel phase: U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U-6Mo-0.6Ru, U-10Mo-0.05Sn, U{sub 2}Mo, or U{sub 3}Si{sub 2}. These experiments will be discharged at peak fuel burnups of 40% and 80%. Of particular interest is the fission gas retention/swelling characteristics of these new fuel alloys. This paper presents the design of the irradiation vehicles and the irradiation conditions.

  9. Results of PIE of experimental (U-Mo)-based LEU disperse fuel compositions

    SciTech Connect

    Vatulin, A.; Dobrikova, I.; Suprun, V.; Petrov, Y.; Trifonov, Y.; Alexandrov, V.; Ijutov, A.; Novoselov, A.; Starkov, V.; Shishin, V.; Yakovlev, V.

    2008-07-15

    Performed in frames of Russian RERTR Program were post-irradiation examinations of 12 types of disperse (U-Mo)-based fuel compositions in Al matrix. The goal of the work was to substantiate serviceability of the new fuel compositions being developed for utilization in Russian-built pool-type research reactors. Among the methods of PIE used in this work were visual examination, gamma-scanning, optical metallography, SEM, X-ray analysis and some others. The present paper is dedicated to an analysis of the main results of PIE completed so far. Special attention has been paid to the parameters affecting formation of interaction layer between fuel granules and matrix Al. (author)

  10. Development on thin wall tubes of dispersion type

    NASA Astrophysics Data System (ADS)

    Zhang, Shien; Wang, Xiyou; Li, Jianshan; Zhang, Rongsheng; Xue, Zhenshu

    A method using powder metallurgy and metallic extrusion to manufacture three kinds of magnesium based thin wall tubes of dispersion type is presented. In each case, the composition of dispersed gold, boron and hafnium in magnesium matrix is 0.5 wt%, 1 wt%, 2 wt%, 4 wt% and 8 wt%, respectively. The diameter of the tubes are 20 mm with wall thickness of 1 mm. The process of mixing, compacting, lubricating, heat-extrusion, checking and die designing are described in detail. Measures for controlling tube tolerance and even distribution of dispersion phase, and improving the surface quality are suggested.

  11. Fuel primer for float type carburetors

    SciTech Connect

    Scott, W.A.

    1988-04-19

    A fuel primer for float type carburetors having a fuel bowl, the fuel bowl coupled with a fuel inlet, an outlet vent, and a nozzle, the fuel inlet coupled with a fuel source and the nozzle coupled with an intake path, the primer is described comprising: means coupled with the outlet for introducing a pressurized fluid flow in the fuel bowl and means associated with the fuel bowl and ambient air for automatically enabling ambient air flow to enter into the fuel bowl upon start up and for enabling fuel flow to enter into the intake path from the fuel bowl during pressurization of the fluid while preventing the fuel flow from exiting the air flow means during pressurization of the fluid such that air enters an engine through the means associated with the fuel bowl and the engine begins to run and continues to run during start up enabling an operator to move a choke from a closed to an open position for continuous operation of the engine.

  12. Post irradiation analysis and performance modeling of dispersion and monolithic U-Mo fuels

    SciTech Connect

    Kim, Yeon Soo; Hofman, G.L.; Medvedev, P.G.; Robinson, A.B.; Shevlyakov, G.V.; Ryu, H.J.

    2008-07-15

    We analyzed fission product swelling of post-irradiation U-Mo fuels from the early RERTR tests to the recent RERTR-8 test. We found that the gas bubble swelling of the fuel-swelling model was overestimated. From the recent tests, RERTR-7A and 8, we could also collect a considerable amount of fuel swelling data from monolithic U-Mo fuel plates. The fuel swelling data from the monolithic fuel plates are considered more reliable because the interaction layer growth between the fuel and matrix in dispersion fuel, which obscures fuel swelling, does not exist. The swelling correlation comparison to the Si-added dispersion fuel data and monolithic fuel data suggested that a modification of the existing model was necessary. We also developed an interaction layer growth model for U-Mo/Al dispersion fuel plates with a Si-added matrix. PLATE code calculations with the new PIE data analysis results were performed. The updated versions predict with better accuracies for both monolithic fuel plates and dispersion fuel plates. In this paper, we present the results of fission product swelling characterization. In addition, the interaction layer growth model for U-Mo/Al with a Si-added matrix is presented. (author)

  13. Far-field dispersal modeling for fuel-air-explosive devices

    SciTech Connect

    Glass, M.W.

    1990-05-01

    A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.

  14. Carbon nanotube dispersed conductive network for microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Matsumoto, S.; Yamanaka, K.; Ogikubo, H.; Akasaka, H.; Ohtake, N.

    2014-08-01

    Microbial fuel cells (MFCs) are promising devices for capturing biomass energy. Although they have recently attracted considerable attention, their power densities are too low for practical use. Increasing their electrode surface area is a key factor for improving the performance of MFC. Carbon nanotubes (CNTs), which have excellent electrical conductivity and extremely high specific surface area, are promising materials for electrodes. However, CNTs are insoluble in aqueous solution because of their strong intertube van der Waals interactions, which make practical use of CNTs difficult. In this study, we revealed that CNTs have a strong interaction with Saccharomyces cerevisiae cells. CNTs attach to the cells and are dispersed in a mixture of water and S. cerevisiae, forming a three-dimensional CNT conductive network. Compared with a conventional two-dimensional electrode, such as carbon paper, the three-dimensional conductive network has a much larger surface area. By applying this conductive network to MFCs as an anode electrode, power density is increased to 176 μW/cm2, which is approximately 25-fold higher than that in the case without CNTs addition. Maximum current density is also increased to approximately 8-fold higher. These results suggest that three-dimensional CNT conductive network contributes to improve the performance of MFC by increasing surface area.

  15. Irradiation behavior of the CNEA's experimental uranium silicide dispersion fuel plates

    SciTech Connect

    Hofman, G.L.; Marajofsky, A.; Kohut, C.; Comision Nacional de Energia Atomica, Buenos Aires )

    1988-01-01

    Since 1978 the CNEA ECBE project has been involved in the development of dispersion fuel plates with four types of fuel materials -- UAl{sub x}, U{sub 3}O{sub 8}, U{sub 3}Si, and U{sub 3}Si{sub 2} -- to be used in low enriched (LEU < 20% {sup 235}U) fuel elements for research reactors. Miniplates with these fuel materials were manufactured at CNEA and were irradiated in the ORR in three series of irradiations as part of the RERTR miniplate irradiation program. The first irradiation contained U{sub 3}O{sub 8} and UAl{sub x} fuel, the second U{sub 3}O{sub 8}, UAl{sub x} and U{sub 3}Si, while the third irradiation test consisted of six U{sub 3}Si{sub 2} miniplates and one U{sub 3}Si miniplate. This third test is the subject of this paper. The present results compare favorably with other irradiations performed in the RERTR program{sup 1,2} showing in particular the excellent behavior of the U{sub 3}Si{sub 2}. The overall data accumulated support the qualification of the CNEA fabrication techniques. 5 refs., 13 figs., 3 tabs.

  16. Dielectric dispersion of Y-type hexaferrites at low frequencies

    NASA Astrophysics Data System (ADS)

    Abo El Ata, A. M.; Attia, S. M.

    2003-02-01

    A series of polycrystalline Y-type hexaferrites with composition Ba 2Ni 2- xZn xFe 12O 22 (where 0.0⩽ x⩽2.0) were prepared by the standard ceramic method to study the effect of the frequency, temperature and composition on their AC electrical conductivity σ' AC, and dielectric properties. It was found that, the AC conductivity shows dispersion at high frequencies. This dispersion was attributed to the interfacial polarization arising from the inhomogeneous structure of the material. At low frequencies the dielectric constant, ɛ', is abnormally high and decreases rapidly with increasing frequency. Dielectric relaxation peaks were observed on the tan δ( F) curves. The results of the dielectric constant and dielectric loss were explained on the basis of the assumption that the mechanism of dielectric polarization is similar to that of the conduction process.

  17. Classification of Fuel Types Using Envisat Data

    NASA Astrophysics Data System (ADS)

    Wozniak, Edyta; Nasilowska, Sylwia

    2010-12-01

    Forest fires have an important impact on landscape structure and ecosystems biodiversity. Moreover, wild land fires have strong influence on forest planning and management. Furthermore, forest fires affect not only woodworking industry but also arable fields and inhabitants life too. A precise knowledge of the spatial distribution of fuels is necessary to predict, analyse and model fire behaviour. Modelling of fire spread is difficult and complicated because it depends on many factors. First of all, it depends on undergrowth and brushwood moisture and thickness, and tree species. There are many fuel types classification developed for regional environmental condition. The main drawback of implemented systems is utility for particular region of interest. That causes a need of permanent, consequent and more accurate researches in specific habitat not only in continental scale. In this paper a new system is proposed. It organizes fuels into three major groups (coniferous, deciduous wood and open) and four subcategories which describes a fuel structure (trees lower then 4m, trees higher than 4 m: without bushes; with low bushes lower them 2m; with high bushes higher then 2m). This classification is adapted into Polish lowlands environmental condition. The classification was carried out on the base of 120 training plots, which were determinate during a field experiment in north-eastern Poland. The plots discriminate homogeneous parts of forest which correspond to fuel classes. In the study we used the ENVISAT Alternating Polarization (HH/HV) image. The most popular classifiers were tried out and the maximum likelihood method resulted the most efficient. To map fuel types many methods are employed. The use of remote sensing systems gives the possibility of low- costs and time-consuming fuels mapping and updating. The employ of SAR systems permits mapping independently of weather condition. The microwave data has the potential to estimate fuel loads and map fuel types. The

  18. Investigation of spray dispersion and particulate formation in diesel fuel flames

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Bankston, C. P.; Kwack, E. Y.; Bellan, J.; Harstad, K.

    1988-01-01

    An experimental study of electrostatical atomized and dispersed diesel fuel jets was conducted at various back pressures to 40 atm. A new electrostatic injection technique was utilized to generate continuous, stable fuel sprays at charge densities of 1.5 to 2.0 C/m3 of fluid at one atm, and about 1.0 C/m3 at 40 atm. Flowrates were varied from 0.5 to 2.5 ml/s and electric potentials to -18 kV. Visual observations showed that significant enhanced dispersion of charged fuel jets occurred at high back pressures compared to aerodynamic breakup and dispersion. The average drop size was about the same as the spray triode orifice diameter, and was between the Kelly theory and the Rayleigh limit. The ignition tests, done only at one atm, indicated stable combustion of the electrostatically dispersed fuel jets.

  19. Modeling a failure criterion for U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Oh, Jae-Yong; Kim, Yeon Soo; Tahk, Young-Wook; Kim, Hyun-Jung; Kong, Eui-Hyun; Yim, Jeong-Sik

    2016-05-01

    The breakaway swelling in U-Mo/Al dispersion fuel is known to be caused by large pore formation enhanced by interaction layer (IL) growth between fuel particles and Al matrix. In this study, a critical IL thickness was defined as a criterion for the formation of a large pore in U-Mo/Al dispersion fuel. Specifically, the critical IL thickness is given when two neighboring fuel particles come into contact with each other in the developed IL. The model was verified using the irradiation data from the RERTR tests and KOMO-4 test. The model application to full-sized sample irradiations such as IRISs, FUTURE, E-FUTURE, and AFIP-1 tests resulted in conservative predictions. The parametric study revealed that the fuel particle size and the homogeneity of the fuel particle distribution are influential for fuel performance.

  20. A model to predict thermal conductivity of irradiated U-Mo dispersion fuel

    NASA Astrophysics Data System (ADS)

    Burkes, Douglas E.; Huber, Tanja K.; Casella, Andrew M.

    2016-05-01

    Numerous global programs are focused on the continued development of existing and new research and test reactor fuels to achieve maximum attainable uranium loadings to support the conversion of a number of the world's remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Some of these programs are focused on assisting with the development and qualification of a fuel design that consists of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix as one option for reactor conversion. Thermal conductivity is an important consideration in determining the operational temperature of the fuel and can be influenced by interaction layer formation between the dispersed phase and matrix and upon the concentration of the dispersed phase within the matrix. This paper extends the use of a simple model developed previously to study the influence of interaction layer formation as well as the size and volume fraction of fuel particles dispersed in the matrix, Si additions to the matrix, and Mo concentration in the fuel particles on the effective thermal conductivity of the U-Mo/Al composite during irradiation. The model has been compared to experimental measurements recently conducted on U-Mo/Al dispersion fuels at two different fission densities with acceptable agreement. Observations of the modeled results indicate that formation of an interaction layer and subsequent consumption of the matrix reveals a rather significant effect on effective thermal conductivity. The modeled interaction layer formation and subsequent consumption of the high thermal conductivity matrix was sensitive to the average dispersed fuel particle size, suggesting this parameter as one of the most effective in minimizing thermal conductivity degradation of the composite, while the influence of Si additions to the matrix in the model was highly dependent upon irradiation conditions.

  1. Microstructural Development in Irradiated U-7Mo/6061 Al Alloy Matrix Dispersion Fuel

    SciTech Connect

    Dennis D. Keiser, Jr.; Adam B. Robinson; Jan-Fong Jue; Pavel G. Medvedev; Daniel M. Wachs; M. Ross Finlay

    2009-09-01

    A U-7Mo alloy/6061 Al alloy matrix dispersion fuel plate was irradiated in the Advanced Test Reactor and then destructively examined using optical metallography and scanning electron microscopy to characterize the developed microstructure. Results were compared to the microstructures of as-fabricated dispersion fuel to identify changes that occurred during irradiation. The interaction layers that formed on the surface of the fuel U-7Mo particles during fuel fabrication exhibited stable irradiation performance as a result of the ~0.88 wt% Si present in the fuel meat matrix. During irradiation, the interaction layers changed very little in thickness and composition. The overall irradiation performance of the fuel plate to moderate power and burnup was considered excellent.

  2. TEM CHARACTERIZATION OF IRRADIATED U3SI2/AL DISPERSION FUEL

    SciTech Connect

    J. Gan; B. Miller; D. Keiser; A. Robinson; P. Medvedev; D. Wachs

    2010-10-01

    The silicide dispersion fuel of U3Si2/Al has been recognized as a reasonably good performance fuel for nuclear research and test reactors except that it requires the use of high enrichment uranium. An irradiated U3Si2/Al dispersion fuel (~75% enrichment) from the high flux side of a RERTR-8 (U0R040) plate was characterized using transmission electron microscopy (TEM). The fuel plate was irradiated in the advanced test reactor (ATR) for 105 days. The average irradiation temperature and fission density of the fuel particles for the TEM sample are estimated to be approximately ~110 degrees C and 5.4 x 10-21 f/cm3. The characterization was performed using a 200KV TEM with a LaB6 filament. Detailed microstructural information along with composition analysis is obtained. The results and their implication on the performance of this silicide fuel are discussed.

  3. Discrete element method study of fuel relocation and dispersal during loss-of-coolant accidents

    NASA Astrophysics Data System (ADS)

    Govers, K.; Verwerft, M.

    2016-09-01

    The fuel fragmentation, relocation and dispersal (FFRD) during LOCA transients today retain the attention of the nuclear safety community. The fine fragmentation observed at high burnup may, indeed, affect the Emergency Core Cooling System performance: accumulation of fuel debris in the cladding ballooned zone leads to a redistribution of the temperature profile, while dispersal of debris might lead to coolant blockage or to debris circulation through the primary circuit. This work presents a contribution, by discrete element method, towards a mechanistic description of the various stages of FFRD. The fuel fragments are described as a set of interacting particles, behaving as a granular medium. The model shows qualitative and quantitative agreement with experimental observations, such as the packing efficiency in the balloon, which is shown to stabilize at about 55%. The model is then applied to study fuel dispersal, for which experimental parametric studies are both difficult and expensive.

  4. Aerodynamic device for generating mono-disperse fuel droplets

    NASA Astrophysics Data System (ADS)

    Green, G. J.; Walsh, D. E.; Takahashi, F.; Dryer, F. L.

    1989-04-01

    A device has been developed for generating well-defined, one-dimensional streams of small monosized droplets of a variety of fuels. The droplets produced are well separated, making this technique well suited to experimental combustion studies of unsupported, isolated droplets. This method has been used successfully to generate droplets of light and middistillate petroleum fuels, heavy oils, boron/JP-10 slurries, and coke/oil slurries, for a range of combustion studies. The principle of operation of the device is the aerodynamic stripping of incompletely formed droplets emerging from the tip of a capillary/fine wire which resides in the throat of a venturi or convergent nozzle.

  5. Estimation of 85Kr dispersion from the spent nuclear fuel reprocessing plant in Rokkasho, Japan, using an atmospheric dispersion model.

    PubMed

    Abe, K; Iyogi, T; Kawabata, H; Chiang, J H; Suwa, H; Hisamatsu, S

    2015-11-01

    The spent nuclear fuel reprocessing plant of Japan Nuclear Fuel Limited (JNFL) located in Rokkasho, Japan, discharged small amounts of (85)Kr into the atmosphere during final tests of the plant with actual spent fuel from 31 March 2006 to October 2008. During this period, the gamma-ray dose rates due to discharged (85)Kr were higher than the background rates measured at the Institute for Environmental Sciences and at seven monitoring stations of the Aomori prefectural government and JNFL. The dispersion of (85)Kr was simulated by means of the fifth-generation Penn State/NCAR Mesoscale Model and the CG-MATHEW/ADPIC models (ver. 5.0) with a vertical terrain-following height coordinate. Although the simulated gamma-ray dose rates due to discharged (85)Kr agreed fairly well with measured rates, the agreement between the estimated monthly mean (85)Kr concentrations and the observed concentrations was poor. Improvement of the vertical flow of air may lead to better estimation of (85)Kr dispersion. PMID:25948824

  6. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    SciTech Connect

    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.

  7. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    NASA Astrophysics Data System (ADS)

    Susmikanti, Mike; Sulistyo, Jos

    2014-09-01

    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.

  8. Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

    DOE PAGESBeta

    Collette, R.; King, J.; Buesch, C.; Keiser, Jr., D. D.; Williams, W.; Miller, B. D.; Schulthess, J.

    2016-04-01

    The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends whenmore » comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. Here, the results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.« less

  9. Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

    NASA Astrophysics Data System (ADS)

    Collette, R.; King, J.; Buesch, C.; Keiser, D. D.; Williams, W.; Miller, B. D.; Schulthess, J.

    2016-07-01

    The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends when comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. The results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.

  10. Dispersal

    USGS Publications Warehouse

    2001-01-01

    The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.

  11. EFFECT OF THE OIL DISPERSANT OMNI-CLEAN(R) ON THE TOXICITY OF FUEL OIL NO. 2 IN TWO BIOASSAYS WITH THE SHEEPSHEAD MINNOW CYPRINODON VARIEGATUS

    EPA Science Inventory

    Bioassays (7-day early life stage and 96h acute bioassays) were conducted with the sheepshead minnow, Cyprinodon variegatus, to determine the toxicity of the dispersant Omni-Clean< by itself and in combination with fuel oil no. 2. Performance characteristics of both bioassay type...

  12. PRELIMINARY INVESTIGATION OF UNCOMBUSTED AUTO FUEL VAPOR DISPERSION WITHIN A RESIDENTIAL GARAGE MICROENVIRONMENT

    EPA Science Inventory

    Evaporative emissions from vehicles in an attached garage may represent a significant source of indoor pollution and human exposure. ilot field study was undertaken to investigate potential in-house dispersion of evaporative emissions of uncombusted fuels from a vehicle parked in...

  13. Comparison of thermal compatibility between atomized and comminuted U{sub 3}Si dispersion fuels

    SciTech Connect

    Ryu, Woo-Seog; Park, Jong-Man; Kim, Chang-Kyu; Kuk, II-Hyun

    1997-08-01

    Thermal compatibility of atomized U{sub 3}Si dispersion fuels were evaluated up to 2600 hours in the temperature range from 250 to 500{degrees}C, and compared with that of comminuted U{sub 3}Si. Atomized U{sub 3}Si showed better performance in terms of volume expansion of fuel meats. The reaction zone of U{sub 3}Si and Al occurred along the grain boundaries and deformation bands in U{sub 3}Si particles. Pores around fuel particles appeared at high temperature or after long-term annealing tests to remain diffusion paths over the trench of the pores. The constraint effects of cladding on fuel rod suppressed the fuel meat, and reduced the volume expansion.

  14. Numerical Simulation of Shock-Dispersed Fuel Charges

    SciTech Connect

    Bell, John B.; Day, Marcus; Beckner, Vincent; Rendleman, Charles; Kuhl, Allen L.; Neuwald, P.

    2005-06-20

    Successfully attacking underground storage facilities for chemical and biological (C/B) weapons is an important mission area for the Department of Defense. The fate of a C/B agent during an attack depends critically on the pressure and thermal environment that the agent experiences. The initial environment is determined by the blast wave from an explosive device. The byproducts of the detonation provide a fuel source that burn when mixed with oxidizer (after burning). Additional energy can be released by the ignition of the C/B agent as it mixes with the explosion products and the air in the chamber. Hot plumes venting material from any openings in the chamber can provide fuel for additional energy release when mixed with additional oxidizer. Assessment of the effectiveness of current explosives as well as the development of new explosive systems requires a detailed understanding of all of these modes of energy release. Using methodologies based on the use of higher-order Godunov schemes combined with Adaptive Mesh Refinement (AMR), implemented in a parallel adaptive framework suited to the massively parallel computer systems provided by the DOD High-Performance Computing Modernization program, we use a suite of programs to develop predictive models for the simulation of the energetics of blast waves, deflagration waves and ejecta plumes. The programs use realistic reaction kinetic and thermodynamic models provided by standard components (such as CHEMKIN) as well as other novel methods to model enhanced explosive devices. The work described here focuses on the validation of these models against a series of bomb calorimetry experiments performed at the Ernst-Mach Institute. In this paper, we present three-dimensional simulations of the experiments, examining the explosion dynamics and the role of subsequent burning on the explosion products on the thermal and pressure environment within the calorimeter. The effects of burning are quantified by comparing two sets of

  15. Electron Microscopy Characterization of an As-Fabricated Research Reactor Fuel Plate Comprised of U-7Mo Particles Dispersed in an Al-2Si Alloy Matrix

    SciTech Connect

    Dennis D. Keiser, Jr.; J. Gan; J. F. Jue; B. D. Miller

    2010-11-01

    To understand the microstructural development of nuclear fuel plates during irradiation, it is imperative to know the microstructure of a fuel plate after all the fabrication steps have been completed and before it is inserted into the reactor. To this end, a U–7 wt.% Mo alloy research reactor dispersion fuel plate with Al–2 wt.% Si matrix was destructively examined using scanning and transmission electron microscopy to characterize the developed microstructure after fabrication. Of particular interest for this study was how the Si that was added to the fuel matrix partitioned between the various fuel plate phases during fabrication. Si was added to the matrix so that the microstructure that developed during fuel fabrication would exhibit good irradiation behavior. SEM analysis was used to identify the representative microstructure, the compositions of the various phases, and the partitioning behavior of the fuel and matrix constituents. TEM analysis was employed to definitively identify the phases in the U–7Mo alloy and the phases that formed due to diffusional interactions between the fuel particles and matrix during fuel plate fabrication. The TEM results are the first reported for an as-fabricated U–7 wt.% Mo dispersion fuel plate with an Al alloy matrix. SEM results showed that a significant portion of the original ?-(U–Mo) fuel particles had transformed to a lamellar microstructure, comprised of a-U and either ? or ?' phases, and the fuel/matrix interaction layers were enriched in Si. TEM analysis identified an ordered fcc (U–Mo)(Al–Si)3 type of phase, which formed at the decomposed U–7Mo/matrix interface and extended into the lamellar microstructure. Some regions of the U–7Mo particles retained the single-phase ?-(U–Mo). Small precipitate phases were observed in the fuel meat matrix that contained Fe, Al, and Si. The Si that is added to the matrix of a U–Mo dispersion fuel plate to improve irradiation performance appears to result in

  16. Results of Recent Microstructural Characterization of Irradiated U-Mo Dispersion Fuels with Al Alloy Matrices that Contain Si

    SciTech Connect

    D. D. Keiser, Jr.; A. B. Robinson; D. E. Janney; J. F. Jue

    2008-03-01

    RERTR U-Mo dispersion fuel plates are being developed for application in research reactors throughout the world. Of particular interest is the irradiation performance of U-Mo dispersion fuels with Si added to the Al matrix. Si is added to improve the performance of U-Mo dispersion fuels. Microstructural examinations have been performed on fuel plates with either Al-0.2Si or 4043 Al (~4.8% Si) alloy matrix in the as-fabricated and/or as-irradiated condition using optical metallography and/or scanning electron microscopy. Fuel plates with either matrix can have Si-rich layers around the U-7Mo particles after fabrication, and during irradiation these layers were observed to grow in thickness and to become Si-deficient in some areas of the fuel plates. For the fuel plates with 4043 Al, this was observed in fuel plate areas that were exposed to very aggressive irradiation conditions.

  17. Performance of Desiccant Particle Dispersion Type Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Hatano, Hiroyuki; Suzuki, Koichi; Kojima, Hiromitsu

    An investigation of desiccant air conditioning system is performed to demonstrate its performance in a dispersed desiccant particle systems, based on its higher gas solid contacting efficiency and isothermal dehumidification. Particle dispersion is achieved using the risers of a circulating fluidized bed, CFB, or of a pneumatic conveyer. The risers used for dehumidification are 1390 mm in height and 22 mm in diameter. The former is used to evaluate the overall dehumidification performance and the latter is used to measure the axial humidity distribution under 0.88 m/s of a superficial air velocity. Based on the results of the overall performance by changing solid loading rates, Gs, from 0.4 kg/m2s up to 6 kg/m2s, desiccant particle dispersion shows higher performance in dehumidification, while axial humidity distribution shows very rapid adsorption rate in the entrance zone of the riser. Removal of adsorption heat accelerates dehumidification rate compared to the adiabatic process.

  18. Safety evaluation report related to the evaluation of low-enriched uranium silicide-aluminum dispersion fuel for use in non-power reactors

    SciTech Connect

    Not Available

    1988-07-01

    Low-enriched uranium silicide-aluminum dispersion plate-type fuels have been extensively researched and developed under the international program, Reduced Enrichment in Research and Test Reactors. The international effort was led by Argonne National Laboratory (ANL) in the United States. This evaluation is based primarily on reports issued by ANL that discuss and summarize the developmental tests and experiments, including postirradiation examinations, of both miniature and full-sized plates of prototypical fuel compositions. This evaluation concludes that plate-type fuels suitable and acceptable for use in research and test reactors can be fabricated with U/sub 3/Si/sub 2/-Al dispersion compacts with uranium densities up to 4.8 g/cm/sup 3/. 4 refs., 1 fig.

  19. Some recent observations on the radiation behavior of uranium silicide dispersion fuel

    SciTech Connect

    Hofman, G.L.

    1988-01-01

    Addition of B{sub 4}C burnable poison results in higher plate swelling in both U{sub 3}Si{sub 2} and U{sub 3}Si-Al dispersion fuel plates and also decreases the blister threshold temperature of these plates. Prolonged annealing of U{sub 3}Si{sub 2}-Al fuel plates produced no blister after 696 hours at 400{degrees}C. Blister formation started between 257 hours and 327 hours at 425{degrees}C and between 115 hours and 210 hours at 450{degrees}C. Operation with breached cladding resulted in pillowing of an U{sub 3}Si-Al fuel plate due to reaction of the fuel core with coolant water. 4 refs., 10 figs., 2 tabs.

  20. NUCLEAR REACTOR FUEL-BREEDER FUEL ELEMENT

    DOEpatents

    Currier, E.L. Jr.; Nicklas, J.H.

    1962-08-14

    A fuel-breeder fuel element was developed for a nuclear reactor wherein discrete particles of fissionable material are dispersed in a matrix of fertile breeder material. The fuel element combines the advantages of a dispersion type and a breeder-type. (AEC)

  1. Preliminary study of a dispersed fringe type sensing system

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Liu, Gen-Rong; Wang, Yue-Fei; Li, Ye-Ping; Zhang, Ya-Jun; Zhang, Liang

    2009-08-01

    Telescopes with large aspherical primary mirrors collect more light and are therefore sought after by astronomers. Instead of using a single large one-piece mirror, smaller segments can be assembled into a useable telescopic primary. Because the segments must fit together to create the effect of a single mirror, segmented optics present unique challenges to the fabrication and testing that are absent in monolithic optics. A dispersed fringe sensor (DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. Unlike the widely adopted Shack-Hartmann Wavefront sensor and curvature wavefront sensor with edge sensors for calibration of relative pistons, DFS can estimate the piston between segments by only using the spectrum formed by the transmissive grating's dispersion, and therefore can replace the edge sensors, which are difficult to calibrate. We introduce the theory of the DFS and Dispersed Hartmann Sensor (DHS) for further utilization of the coarse phasing method of DFS. According to the theory, we bring out the preliminary system design of the cophasing experimental system based on DFS and DHS which is now established in our institute. Finally, a summary is reached.

  2. Air blast type coal slurry fuel injector

    DOEpatents

    Phatak, R.G.

    1984-08-31

    A device to atomize and inject a coal slurry in the combustion chamber of an internal combustion engine is disclosed which eliminates the use of a conventional fuel injection pump/nozzle. The injector involves the use of compressed air to atomize and inject the coal slurry and like fuels. In one embodiment, the breaking and atomization of the fuel is achieved with the help of perforated discs and compressed air. In another embodiment, a cone shaped aspirator is used to achieve the breaking and atomization of the fuel. The compressed air protects critical bearing areas of the injector.

  3. Air blast type coal slurry fuel injector

    DOEpatents

    Phatak, Ramkrishna G.

    1986-01-01

    A device to atomize and inject a coal slurry in the combustion chamber of an internal combustion engine, and which eliminates the use of a conventional fuel injection pump/nozzle. The injector involves the use of compressed air to atomize and inject the coal slurry and like fuels. In one embodiment, the breaking and atomization of the fuel is achieved with the help of perforated discs and compressed air. In another embodiment, a cone shaped aspirator is used to achieve the breaking and atomization of the fuel. The compressed air protects critical bearing areas of the injector.

  4. Fast Reactor Fuel Type and Reactor Safety Performance

    SciTech Connect

    R. Wigeland; J. Cahalan

    2009-09-01

    Fast Reactor Fuel Type and Reactor Safety Performance R. Wigeland , Idaho National Laboratory J. Cahalan, Argonne National Laboratory The sodium-cooled fast neutron reactor is currently being evaluated for the efficient transmutation of the highly-hazardous, long-lived, transuranic elements that are present in spent nuclear fuel. One of the fundamental choices that will be made is the selection of the fuel type for the fast reactor, whether oxide, metal, carbide, nitride, etc. It is likely that a decision on the fuel type will need to be made before many of the related technologies and facilities can be selected, from fuel fabrication to spent fuel reprocessing. A decision on fuel type should consider all impacts on the fast reactor system, including safety. Past work has demonstrated that the choice of fuel type may have a significant impact on the severity of consequences arising from accidents, especially for severe accidents of low probability. In this paper, the response of sodium-cooled fast reactors is discussed for both oxide and metal fuel types, highlighting the similarities and differences in reactor response and accident consequences. Any fast reactor facility must be designed to be able to successfully prevent, mitigate, or accommodate all consequences of potential events, including accidents. This is typically accomplished by using multiple barriers to the release of radiation, including the cladding on the fuel, the intact primary cooling system, and most visibly the reactor containment building. More recently, this has also included the use of ‘inherent safety’ concepts to reduce or eliminate the potential for serious damage in some cases. Past experience with oxide and metal fuel has demonstrated that both fuel types are suitable for use as fuel in a sodium-cooled fast reactor. However, safety analyses for these two fuel types have also shown that there can be substantial differences in accident consequences due to the neutronic and

  5. Calculation of Design Parameters for an Equilibrium LEU Core in the NBSR using a U7Mo Dispersion Fuel

    SciTech Connect

    Hanson A. L.; Diamond D.

    2014-06-30

    A plan is being developed for the conversion of the NIST research reactor (NBSR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. The LEU fuel may be a monolithic foil (LEUm) of U10Mo (10% molybdenum by weight in an alloy with uranium) or a dispersion of U7Mo in aluminum (LEUd). A previous report provided neutronic calculations for the LEUm fuel and this report presents the neutronics parameters for the LEUd fuel. The neutronics parameters for the LEUd fuel are compared to those previously obtained for the present HEU fuel and the proposed LEUm fuel. The results show no significant differences between the LEUm and the LEUd other than the LEUd fuel requires slightly less uranium than the LEUm fuel due to less molybdenum being present. The calculations include kinetics parameters, reactivity coefficients, reactivity worths of control elements and abnormal configurations, and power distributions under normal operation and with misloaded fuel elements.

  6. Two types of ion energy dispersions observed in the nightside auroral regions during geomagnetically disturbed periods

    NASA Astrophysics Data System (ADS)

    Hirahara, M.; Mukai, T.; Nagai, T.; Kaya, N.; Hayakawa, H.; Fukunishi, H.

    1996-04-01

    The Akebono satellite has observed two types of energy dispersion signatures of discrete ion precipitation event in the nightside auroral regions during active geomagnetic conditions. The charged particle experiments and electric and magnetic field detectors on board Akebono provide us with essential clues to characterize the source regions and acceleration and/or injection processes associated with these two types of ion signatures. The magnetic field data obtained simultaneously by the geosynchronous GOES 6 and 7 satellites and the ground magnetograms are useful to examine their relationships with geomagnetic activity. Mass composition data and pitch angle distributions show that different sources and processes should be attributed to two types (Types I and II) of energy dispersion phenomena. Type I consists of multiple bouncing ion clusters constituted by H+. These H+ clusters tend to be detected at the expansion phase of substorms and have characteristic multiple energy-dispersed signatures. Type II consists of O+ energy dispersion(s), which is often observed at the recovery phase. It is reasonable to consider that the H+ clusters of Type I are accelerated by dipolarization at the equator, are injected in the field-aligned direction, and bounce on closed field lines after the substorm onset. We interpret these multiple energy dispersion events as mainly due to the time-of-flight (TOF) effect, although the convection may influence the energy-dispersed traces. Based of the TOF model, we estimate the source distance to be 20-30 RE along the field lines. On the other hand, the O+ energy dispersion of Type II is a consequence of reprecipitation of terrestrial ions ejected as an upward flowing ion (UFI) beam from the upper ionosphere by a parallel electrostatic potential difference. The O+ energy dispersion is induced by the E×B drift during the field-aligned transport from the source region to the observation point.

  7. Autoignition characteristics of aircraft-type fuels

    NASA Technical Reports Server (NTRS)

    Spadaccini, L. J.; Tevelde, J. A.

    1980-01-01

    The ignition delay characteristics of Jet A, JP 4, no. 2 diesel, cetane and an experimental referee broad specification (ERBS) fuel in air at inlet temperatures up to 1000 K, pressures of 10, 15, 20, 25 and 30 atm, and fuel air equivalence ratios of 0.3, 0.5, 0.7 and 1.0 were mapped. Ignition delay times in the range of 1 to 50 msec at freestream flow velocities ranging from 20 to 100 m/sec were obtained using a continuous flow test apparatus which permitted independent variation and evaluation of the effect of temperature, pressure, flow rate, and fuel/air ratio. The ignition delay times for all fuels tested appeared to correlate with the inverse of pressure and the inverse exponent of temperature. With the exception of pure cetane, which had the shortest ignition delay times, the differences between the fuels tested did not appear to be significant. The apparent global activation energies for the typical gas turbine fuels ranged from 38 to 40 kcal/mole, while the activation energy determined for cetane was 50 kcal/mole. In addition, the data indicate that for lean mixtures, ignition delay times decrease with increasing equivalence ratio. It was also noted that physical (apparatus dependent) phenomena, such as mixing (i.e., length and number of injection sites) and airstream cooling (due to fuel heating, vaporization and convective heat loss) can have an important effect on the ignition delay.

  8. Results of Recent Microstructural Characterization of Irradiated U-Mo Dispersion Fuels with Al Alloy Matrices that Contain Si

    SciTech Connect

    D D. Keiser, Jr.; A. B. Robinson; D. E. Janney; J. F. Jue

    2008-03-01

    RERTR U-Mo dispersion fuel plates are being developed for application in research reactors throughout the world. As part of this development, reactor experiments are being conducted in the Advanced Test Reactor to determine the irradiation performance of different dispersion fuels that contain U-Mo alloys with different Mo contents and Al alloy matrices with different Si contents. Of particular interest is the performance of the dispersion fuels depending on the Si content of the Al alloy matrix, since the addition of Si is being looked to for improving the performance of these dispersion fuels. This paper will describe the results of recent microstructural examinations that have been performed using optical metallography and scanning electron microscopy on as-fabricated and as-irradiated dispersion fuels with different amounts of Si added to the Al matrix. Differences in the microstructural development during irradiation as a function of the Si content in the Al matrix will be discussed, and comments will be made about the development and stability of the fuel/matrix interaction layers that are commonly present in irradiated dispersion fuels.

  9. Measurement of fission gas release from irradiated Usbnd Mo dispersion fuel samples

    NASA Astrophysics Data System (ADS)

    Burkes, Douglas E.; Casella, Amanda J.; Casella, Andrew M.

    2016-09-01

    The uranium-molybdenum (Usbnd Mo) alloy dispersed in an Alsbnd Si matrix has been proposed as one fuel design capable of converting some of the world's highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. In this paper, two irradiated samples containing 53.9 vol% U-7wt% Mo fuel particles dispersed in an Al-2wt% Si matrix were subjected to specified thermal profiles under a controlled atmosphere using a thermogravimetric/differential thermal analyzer coupled with a mass spectrometer inside a hot cell. Measurements revealed three distinct fission gas release events for the samples from 400 to 700 °C, as well as a number of minor fission gas releases below and above this temperature range. The mechanisms responsible for these events are discussed, and the results have been compared with available information in the literature with exceptional agreement.

  10. Fabrication of particle dispersed inert matrix fuel based on liquid phase sintered SiC

    NASA Astrophysics Data System (ADS)

    Pavlyuchkov, D.; Baney, R. H.; Tulenko, J. S.; Seifert, H. J.

    2011-08-01

    In the present work, liquid phase sintered SiC (LPS-SiC) was proposed as an inert matrix for the particle dispersed inert matrix fuel (IMF). The fuel particles containing plutonium and minor actinides were substituted with pure yttria stabilized zirconia beads. The LPS-SiC matrix was produced from the initial mixtures prepared using submicron sized α-SiC powder and oxide additives Al 2O 3, Y 2O 3 in the amount of 10 wt.% with the molar ratio 1Y 2O 3/1Al 2O 3. Powder mixtures were sintered using two sintering methods; namely conventional high temperature sintering and novel spark plasma sintering at different temperatures depending on the method applied in order to obtain dense samples. The phase reaction products were identified using X-ray diffraction (XRD) and microstructures were investigated using light microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) techniques. The influence of powder mixing methods, sintering temperatures, pressures applied and holding time on the density of the obtained pellets was investigated. The samples sintered by slow conventional sintering show lower relative density and more pronounced interaction between the fuel particles and matrix in comparison with those obtained with the fast spark plasma sintering method.

  11. Some Effects of Air and Fuel Oil Temperatures on Spray Penetration and Dispersion

    NASA Technical Reports Server (NTRS)

    Gelalles, A G

    1930-01-01

    Presented here are experimental results obtained from a brief investigation of the appearance, penetration, and dispersion of oil sprays injected into a chamber of highly heated air at atmospheric pressure. The development of single sprays injected into a chamber containing air at room temperature and at high temperature was recorded by spray photography equipment. A comparison of spray records showed that with the air at the higher temperature, the spray assumed the appearance of thin, transparent cloud, the greatest part of which rapidly disappeared from view. With the chamber air at room temperature, a compact spray with an opaque core was obtained. Measurements of the records showed a decrease in penetration and an increase in the dispersion of the spray injected into the heated air. No ignition of the fuel injected was observed or recorded until the spray particles came in contact with the much hotter walls of the chamber about 0.3 second after the start of injection.

  12. DART model for thermal conductivity of U{sub 3}Si{sub 2} aluminum dispersion fuel

    SciTech Connect

    Rest, J.; Snelgrove, J.L.; Hofman, G.L.

    1995-09-01

    This paper describes the primary physical models that form the basis of the DART model for calculating irradiation-induced changes in the thermal conductivity of aluminium dispersion fuel. DART calculations of fuel swelling, pore closure, and thermal conductivity are compared with measured values.

  13. Dispersion of Single Walled Carbon Nanotubes Using a Novel Type of Sonication: Focused Sonication.

    PubMed

    Sachin, Bramhe N; Ae, Hwangbo Seon; Chu, Min Cheol

    2016-03-01

    We demonstrate the use of novel type of sonication method, focused sonication, with added advantages over bath and probe type of sonication for the dispersion of single walled carbon nanotubes (SWNT). Di-chloro benzene was used as the solvent for dispersion of SWNT. Results from focused sonication and bath sonication were compared and found that focused sonication results in better dispersion. Also Raman spectroscopy was analysed to ascertain if focused sonication causes any damage to the tubes and it was found that there was no damage to the SWNT. We believe that with the added advantages like in-situ temperature control and large sample volume processing, focused sonication would prove to be the most proficient method of sonication for dispersion of nanoparticles. PMID:27455717

  14. Type Ia Supernova Intrinsic Magnitude Dispersion and the Fitting of Cosmological Parameters

    SciTech Connect

    Kim, Alex G

    2010-12-10

    I present an analysis for fitting cosmological parameters from a Hubble Diagram of a standard candle with unknown intrinsic magnitude dispersion. The dispersion is determined from the data themselves, simultaneously with the cosmological parameters. This contrasts with the strategies used to date. The advantages of the presented analysis are that it is done in a single fit (it is not iterative), it provides a statistically founded and unbiased estimate of the intrinsic dispersion, and its cosmological-parameter uncertainties account for the intrinsic dispersion uncertainty. Applied to Type Ia supernovae, my strategy provides a statistical measure to test for sub-types and assess the significance of any magnitude corrections applied to the calibrated candle. Parameter bias and differences between likelihood distributions produced by the presented and currently-used fitters are negligibly small for existing and projected supernova data sets.

  15. Traveling waves for conservation laws with cubic nonlinearity and BBM type dispersion

    NASA Astrophysics Data System (ADS)

    Shearer, Michael; Spayd, Kimberly R.; Swanson, Ellen R.

    2015-10-01

    Scalar conservation laws with non-convex fluxes have shock wave solutions that violate the Lax entropy condition. In this paper, such solutions are selected by showing that some of them have corresponding traveling waves for the equation supplemented with dissipative and dispersive higher-order terms. For a cubic flux, traveling waves can be calculated explicitly for linear dissipative and dispersive terms. Information about their existence can be used to solve the Riemann problem, in which we find solutions for some data that are different from the classical Lax-Oleinik construction. We consider dispersive terms of a BBM type and show that the calculation of traveling waves is somewhat more intricate than for a KdV-type dispersion. The explicit calculation is based upon the calculation of parabolic invariant manifolds for the associated ODE describing traveling waves. The results extend to the p-system of one-dimensional elasticity with a cubic stress-strain law.

  16. Fuel type impact at heat exchanger performance

    NASA Astrophysics Data System (ADS)

    Durčanský, Peter; Patsch, Marek; Jandačka, Jozef

    2016-06-01

    Possible solution to the increasing energy consumption in the world may be use of alternative energy sources in micro-cogeneration in combination with increasing energy effectiveness. The use of renewable sources, such as biomass, represents an important contribution to possible solution of this problem. When designing a new heat source it is required to follow a number of technical regulations and recommendations. The proposed combustion furnace is intended for combustion of biomass, either piece, or in the form of wood biomass. But the combustion is not only affected by design of furnace, but also by fuel and its properties.

  17. Accounting for the dispersion in the x ray properties of early-type galaxies

    NASA Technical Reports Server (NTRS)

    White, Raymond E., III; Sarazin, Craig L.

    1990-01-01

    The x ray luminosities of early-type galaxies are correlated with their optical (e.g., blue) luminosities (L sub X approx. L sub B exp 1.6), but the x ray luminosities exhibit considerable scatter for a given optical luminosity L sub B. This dispersion in x ray luminosity is much greater than the dispersion of other properties of early-type galaxies (for a given L sub B), such as luminosity scale-length, velocity dispersion, color, and metallicity. Here, researchers consider several possible sources for the dispersion in x ray luminosity. Some of the scatter in x ray luminosity may result from stellar population variations between galaxies with similar L sub B. Since the x ray emitting gas is from accumulated stellar mass loss, the L sub X dispersion may be due to variations in integrated stellar mass loss rates. Another possible cause of the L sub X dispersion may be variations in the amount of cool material in the galaxies; cool gas may act as an energy sink for the hot gas. Infrared emission may be used to trace such cool material, so researchers look for a correlation between the infrared emission and the x ray emission of early-type galaxies at fixed L sub B. Velocity dispersion variations between galaxies of similar L sub B may also contribute to the L sub X dispersion. The most likely a priori source of the dispersion in L sub X is probably the varying amount of ram-pressure stripping in a range of galaxy environments. The hot gaseous halos of early-type galaxies can be stripped in encounters with other galaxies or with ambient cluster gas if the intracluster gas is sufficiently dense. Researchers find that the most likely cause of dispersion in the x ray properties of early type galaxies is probably the ram-pressure stripping of gaseous halos from galaxies. For a sample of 81 early-type galaxies with x ray luminosities or upper limits derived from Einstein Observatory observations (CFT) researchers calculated the cumulative distribution of angular distances

  18. Experimental observation of different soliton types in a net-normal group-dispersion fiber laser.

    PubMed

    Feng, Zhongyao; Rong, Qiangzhou; Qiao, Xueguang; Shao, Zhihua; Su, Dan

    2014-09-20

    Different soliton types are observed in a net-normal group-dispersion fiber laser based on nonlinear polarization rotation for passive mode locking. The proposed laser can deliver a dispersion-managed soliton, typical dissipation solitons, and a quasi-harmonic mode-locked pulse, a soliton bundle, and especially a dark pulse by only appropriately adjusting the linear cavity phase delay bias using one polarization controller at the fixed pump power. These nonlinear waves show different features, including the spectral shapes and time traces. The experimental observations show that the five soliton types could exist in the same laser cavity, which implies that integrable systems, dissipative systems, and dark pulse regimes can transfer and be switched in a passively mode-locked laser. Our studies not only verify the numeral simulation of the different soliton-types formation in a net-normal group-dispersion operation but also provide insight into Ginzburg-Landau equation systems. PMID:25322103

  19. Spent fuel sabotage test program, characterization of aerosol dispersal : interim final report.

    SciTech Connect

    Gregson, Michael Warren; Brockmann, John E.; Loiseau, Olivier; Klennert, Lindsay A.; Nolte, Oliver; Molecke, Martin Alan; Autrusson, Bruno A.; Koch, Wolfgang; Pretzsch, Gunter Guido; Brucher, Wenzel; Steyskal, Michele D.

    2008-03-01

    This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program provides source-term data that are relevant to plausible sabotage scenarios in relation to spent fuel transport and storage casks and associated risk assessments. We present details and significant results obtained from this program from 2001 through 2007. Measured aerosol results include: respirable fractions produced; amounts, nuclide content, and produced particle size distributions and morphology; measurements of volatile fission product species enhanced sorption--enrichment factors onto respirable particles; and, status on determination of the spent fuel ratio, SFR, needed for scaling studies. Emphasis is provided on recent Phase 3 tests using depleted uranium oxide pellets plus non-radioactive fission product dopants in surrogate spent fuel test rodlets, plus the latest surrogate cerium oxide results and aerosol laboratory supporting calibration work. The DUO{sub 2}, CeO{sub 2}, plus fission product dopant aerosol particle results are compared with available historical data. We also provide a status review on continuing preparations for the final Phase 4 in this program, tests using individual short rodlets containing actual spent fuel from U.S. PWR reactors, with both high- and lower-burnup fuel. The source-term data, aerosol results, and program design have been tailored to support and guide follow-on computer modeling of aerosol dispersal hazards and radiological consequence assessments. This spent fuel sabotage, aerosol test program was performed primarily at Sandia National Laboratories, with support provided by both the U.S. Department of Energy and the Nuclear Regulatory Commission. This program has significant input from, and is cooperatively

  20. Dispersion-type Hall resistance in InSb|Pt hybrid systems

    PubMed Central

    Shiomi, Y.; Saitoh, E.

    2016-01-01

    In nonmagnetic semiconductors and metals, most of Hall resistance exhibits a linear dependence with applied magnetic fields. In this work, by combining conduction in a metal and a semiconductor under external magnetic fields, we realize a dispersion-type magnetic-field dependence of Hall resistance. The dispersion-type Hall resistance appears in a broad temperature range below 150 K, where quantum linear magnetoresistance is noticeable in the semiconductor substrate. This unconventional Hall response in metal|semiconductor hybrid systems is explained by a change in dominant conduction from the semiconductor to the metal with increasing magnetic field strength. PMID:26908361

  1. R and D of Oxide Dispersion Strengthening Steels for High Burn-up Fuel Claddings

    SciTech Connect

    Kimura, A.; Cho, H.S.; Lee, J.S.; Kasada, R.; Ukai, S.; Fujiwara, M.

    2004-07-01

    Research and development of fuel clad materials for high burn-up operation of light water reactor and super critical water reactor (SCPWR) will be shown with focusing on the effort to overcome the requirements of material performance as the fuel clad. Oxide dispersion strengthening (ODS) steels are well known as a high temperature structural material. Recent irradiation experiments indicated that the steels were quite highly resistant to neutron irradiation embrittlement, showing hardening without accompanying loss of ductility. High Cr ODS steels whose chromium concentration was in the range from 15 to 19 wt% showed high resistance to corrosion in supercritical pressurized water (SCPW). As for the susceptibility to hydrogen embrittlement of ODS steels, the critical hydrogen concentration required to hydrogen embrittlement is ranging 10{approx}12 wppm that is approximately one order of magnitude higher value than that of 9Cr reduced activation ferritic (RAF) steel. In the ODS steels, the fraction of helium desorption by bubble migration mechanism was smaller than that in the RAF steel, indicating that the ODS steels are also resistant to helium He bubble-induced embrittlement. Finally, it is demonstrated that the ODS steels are very promising for the fuel clad material for high burn-up operation of water-cooling reactors. (authors)

  2. Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

    SciTech Connect

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Nicolas E. Woolstenhulme

    2010-06-01

    During fabrication of U-7Mo dispersion fuels, exposure to relatively high temperatures affects the final microstructure of a fuel plate before it is inserted into a reactor. One impact of this high temperature exposure is a chemical interaction that can occur between dissimilar materials. For U-7Mo dispersion fuels, the U-7Mo particles will interact to some extent with the Al or Al alloy matrix to produce interaction products. It has been observed that the final irradiation behavior of a fuel plate can depend on the amount of interaction that occurs at the U-7Mo/matrix interface during fabrication, along with the type of phases that develop at this interface. For the case where a U-7Mo dispersion fuel has a Si-containing Al alloy matrix and is rolled at around 500°C, a Si-rich interaction product has been observed to form that can potentially have a positive impact on fuel performance during irradiation. This interaction product can exhibit stable irradiation behavior and it can act as a diffusion barrier to additional U-Mo/matrix interaction during irradiation. However, for U-7Mo dispersion fuels with softer claddings that are rolled at lower temperatures (e.g., near 425°C), a significant interaction layer has not been observed to form. As a result, the bulk of any interaction layer that develops in these fuels happens during irradiation, and the layer that forms may not exhibit as stable a behavior as one that is formed during fabrication. Therefore, it may be beneficial to add a heat treatment step during the fabrication of dispersion fuel plates with softer cladding alloys that will result in the formation of a uniform, Si-rich interaction layer that is a few microns thick around the U-Mo fuel particles. This type of layer would have characteristics like the one that has been observed in dispersion fuel plates with AA6061 cladding that are fabricated at 500°C, which may exhibit increased stability during irradiation. This report discusses the result of

  3. The calculation of surface orbital energies for specific types of active sites on dispersed metal catalysts

    SciTech Connect

    Augustine, R.L.; Lahanas, K.M.; Cole, F.

    1992-11-01

    An angular overlap calculation has been used to determine the s, p, and d orbital energy levels of the different types of surface sites present on dispersed metal catalysts. These data can permit a Frontier Molecular Orbital treatment of specific site activities as long as the surface orbital availability for overlap with adsorbed substrates is considered along with its energy value and symmetry.

  4. The calculation of surface orbital energies for specific types of active sites on dispersed metal catalysts

    SciTech Connect

    Augustine, R.L.; Lahanas, K.M.; Cole, F.

    1992-01-01

    An angular overlap calculation has been used to determine the s, p, and d orbital energy levels of the different types of surface sites present on dispersed metal catalysts. These data can permit a Frontier Molecular Orbital treatment of specific site activities as long as the surface orbital availability for overlap with adsorbed substrates is considered along with its energy value and symmetry.

  5. Pyrochlore-type catalysts for the reforming of hydrocarbon fuels

    SciTech Connect

    Berry, David A.; Shekhawat, Dushyant; Haynes, Daniel; Smith, Mark; Spivey, James J.

    2012-03-13

    A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A.sub.2-w-xA'.sub.wA''.sub.xB.sub.2-y-zB'.sub.yB''.sub.zO.sub.7-.DELTA.. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H.sub.2+CO) for fuel cells, among other uses.

  6. Improved performance of U-Mo dispersion fuel by Si addition in Al matrix.

    SciTech Connect

    Kim, Y S; Hofman, G L

    2011-06-01

    The purpose of this report is to collect in one publication and fit together work fragments presented in many conferences in the multi-year time span starting 2002 to the present dealing with the problem of large pore formation in U-Mo/Al dispersion fuel plates first observed in 2002. Hence, this report summarizes the excerpts from papers and reports on how we interpreted the relevant results from out-of-pile and in-pile tests and how this problem was dealt with. This report also provides a refined view to explain in detail and in a quantitative manner the underlying mechanism of the role of silicon in improving the irradiation performance of U-Mo/Al.

  7. Simple test for toxicity of number 2 fuel oil and oil dispersants to embryos of grass shrimp, palaemonetes pugio

    SciTech Connect

    Fisher, W.S.; Foss, S.S.

    1993-01-01

    A simple test, using embryos of the grass shrimp Palaemonetes pugio, was employed to determine the toxicity of two commercial oil dispersants (Corexit 7664 and Corexit 9527) and toxicity of the water soluble fraction of Number 2 fuel oil (WSF oil) prepared with and without the addition of the dispersants. Tests revealed P. pugio embryos were similar to previously measured life stages in their sensitivity to WSF oil prepared without dispersants. They were approximately ten times more sensitive to water soluble fractions of dispersed oil, which may have been due to the approximately ten-fold increases in total hydrocarbons measured analytically. Both temperatures and salinity of the sea water affected toxicity of WSF prepared with dispersants, the most obvious effect being earlier onset of mortalities at higher temperatures. (Copyright (c) 1993 Pergamon Press Ltd.)

  8. Liquid Fuel Emulsion Jet-in-Crossflow Penetration and Dispersion Under High Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Gomez, Guillermo Andres

    The current work focuses on the jet-in-crossflow penetration and dispersion behavior of water-in-oil emulsions in a high pressure environment. Both fuel injection strategies of using a water-in-oil emulsion and a jet-in-crossflow have demonstrated unique benefits in improving gas turbine performance from an emissions and efficiency standpoint. A jet-in-crossflow is very practical for use in gas turbine engines, rocket propulsion, and aircraft engines since it utilizes already available crossflow air to atomize fuel. Injecting water into a combustion chamber in the form of a water-in-oil emulsion allows for pollutant emissions reduction while reducing efficiency loses that may result from using a separate water or steam injection circuit. Dispersion effects on oil droplets are expected, therefore investigating the distribution of both oil and water droplets in the crossflow is an objective in this work. Understanding the synchronization and injection behavior of the two strategies is of key interest due to their combined benefits. A water-to-oil ratio and an ambient pressure parameter are developed for emulsion jet-in-crossflow trajectories. To this end, a total of 24 emulsion jet-in-crossflow tests were performed with varying ambient pressures of 2-8 atm and momentum flux ratios of 50, 85, and 120. Sobel edge filtering was applied to each averaged image obtained from a high speed video of each test case. Averaged and filtered images were used to resolve top and bottom edges of the trajectory in addition to the overall peak intensity up to 40 mm downstream of the injection point. An optimized correlation was established and found to differ from literature based correlations obtained under atmospheric pressure conditions. Overall it was found that additional parameters were not necessary for the top edge and peak intensity correlations, but a need for a unique emulsion bottom edge and width trajectory correlation was recognized. In addition to investigating emulsion

  9. Improved Irradiation Performance of Uranium-Molybdenum/Aluminum Dispersion Fuel by Silicon Addition in Aluminum

    SciTech Connect

    Yeon Soo Kim; G. L. Hofman; A. B. Robinson; D. M. Wachs

    2013-10-01

    Uranium-molybdenum fuel particle dispersion in aluminum is a form of fuel under development for conversion of high-power research and test reactors from highly enriched to low-enriched uranium in the U.S. Global Threat Reduction Initiative program (also known as the Reduced Enrichment for Research and Test Reactors program). Extensive irradiation tests have been conducted to find a solution for problems caused by interaction layer growth and pore formation between U-Mo and Al. Adding a small amount of Si (up to [approximately]5 wt%) in the Al matrix was one of the proposed remedies. The effect of silicon addition in the Al matrix was examined using irradiation test results by comparing side-by-side samples with different Si additions. Interaction layer growth was progressively reduced with increasing Si addition to the matrix Al, up to 4.8 wt%. The Si addition also appeared to delay pore formation and growth between the U-Mo and Al.

  10. Fuel dispersal in high-speed aircraft/soil impact scenarios

    SciTech Connect

    Tieszen, S.R.; Attaway, S.W.

    1996-01-01

    The objective of this study is to determine how the jet fuel contained in aircraft wing tanks disperses on impact with a soft terrain, i.e., soils, at high impact velocities. The approach used in this study is to combine experimental and numerical methods. Tests were conducted with an approximately 1/42 linear-scale mass-model of a 1/4 span section of a C-141 wing impacting a sand/clay mixture. The test results showed that within the uncertainty of the data, the percentage of incident liquid mass remaining in the crater is the same as that qualitatively described in earlier napalm bomb development studies. Namely, the percentage of fuel in the crater ranges from near zero for grazing impacts to 25%--50% for high angles of impact. To support a weapons system safety assessment (WSSA), the data from the current study have been reduced to correlations. The numerical model used in the current study is a unique coupling of a Smooth Particle Hydrodynamics (SPH) method with the transient dynamics finite element code PRONTO. Qualitatively, the splash, erosion, and soil compression phenomena are all numerically predicted. Quantitatively, the numerical method predicted a smaller crater cross section than was observed in the tests.

  11. High-temperature Chemical Compatibility of As-fabricated TRIGA Fuel and Type 304 Stainless Steel Cladding

    SciTech Connect

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Eric Woolstenhulme; Kurt Terrani; Glenn A. Moore

    2012-09-01

    Chemical interaction between TRIGA fuel and Type-304 stainless steel cladding at relatively high temperatures is of interest from the point of view of understanding fuel behavior during different TRIGA reactor transient scenarios. Since TRIGA fuel comes into close contact with the cladding during irradiation, there is an opportunity for interdiffusion between the U in the fuel and the Fe in the cladding to form an interaction zone that contains U-Fe phases. Based on the equilibrium U-Fe phase diagram, a eutectic can develop at a composition between the U6Fe and UFe2 phases. This eutectic composition can become a liquid at around 725°C. From the standpoint of safe operation of TRIGA fuel, it is of interest to develop better understanding of how a phase with this composition may develop in irradiated TRIGA fuel at relatively high temperatures. One technique for investigating the development of a eutectic phase at the fuel/cladding interface is to perform out-of-pile diffusion-couple experiments at relatively high temperatures. This information is most relevant for lightly irradiated fuel that just starts to touch the cladding due to fuel swelling. Similar testing using fuel irradiated to different fission densities should be tested in a similar fashion to generate data more relevant to more heavily irradiated fuel. This report describes the results for TRIGA fuel/Type-304 stainless steel diffusion couples that were annealed for one hour at 730 and 800°C. Scanning electron microscopy with energy- and wavelength-dispersive spectroscopy was employed to characterize the fuel/cladding interface for each diffusion couple to look for evidence of any chemical interaction. Overall, negligible fuel/cladding interaction was observed for each diffusion couple.

  12. SIMPLE TEST FOR TOXICITY OF NUMBER 2 FUEL OIL AND OIL DISPERSANTS TO EMBRYOS OF GRASS SHRIMP, PALAEMONETES PUGIO

    EPA Science Inventory

    A simple test, using embryos of the grass shrimp Palaemonetes pugio, was employed to determine the toxicity of two commercial oil dispersants (Corexit 7664 and Corexit 9527) and toxicity of the water soluble fraction of Number 2 fuel oil (WSF oil) prepared with and without the ad...

  13. Preparation of O/I1-type Emulsions and S/I1-type Dispersions Encapsulating UV-Absorbing Agents.

    PubMed

    Aramaki, Kenji; Kimura, Minami; Masuda, Kazuki

    2015-01-01

    Oil-in-cubic phase (O/I1) emulsions encapsulating the cosmetic UV absorbing agents 2-ethylhexyl 4-methoxycinnamate (EHMC), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene, OCR) and 1-(4-tertbutylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione (Avobenzone, TBMP) were prepared by vortex mixing accompanied by a heating-cooling process. A ternary phase diagram in a water/C12EO25/EHMC system at 25°C was constructed and the two-phase equilibrium of an oil phase and an I1 phase, which is necessary to prepare the O/I1-type emulsions, was confirmed. Also, the melting of the I1 phase into a fluid micellar solution phase was confirmed, allowing emulsification by a heating-cooling process. The O/I1-type emulsions were formulated in the ternary system as well as a quaternary system. The four-component system contained an additional cosolvent, isopropyl myristate (IPM). The use of the cosolvent allows the use of reduced amounts of EHMC, which is desirable because EHMC can cause temporary skin irritation. Formulation of the O/I1-type emulsions with other UV absorbing agents (OCR and TBMP) was also possible using the same emulsification method. When IPM was changed to tripalmitin, which has a melting point greater than room temperature, a solid-oil dispersion in I1 phase was formed. We have termed this a "solidin-cubic phase (S/I1) type dispersion". These novel emulsions have not been reported previously. The UV absorbability of the O/I1-type emulsions and S/I1-type dispersions that encapsulate the UV absorbing agents was confirmed by measurement of UV absorption spectra. PMID:26178999

  14. FABRICATION OF TUBE TYPE FUEL ELEMENT FOR NUCLEAR REACTORS

    DOEpatents

    Loeb, E.; Nicklas, J.H.

    1959-02-01

    A method of fabricating a nuclear reactor fuel element is given. It consists essentially of fixing two tubes in concentric relationship with respect to one another to provide an annulus therebetween, filling the annulus with a fissionablematerial-containing powder, compacting the powder material within the annulus and closing the ends thereof. The powder material is further compacted by swaging the inner surface of the inner tube to increase its diameter while maintaining the original size of the outer tube. This process results in reduced fabrication costs of powdered fissionable material type fuel elements and a substantial reduction in the peak core temperatures while materially enhancing the heat removal characteristics.

  15. The effect of navigation state selection on fuel dispersions for powered lunar descent

    NASA Astrophysics Data System (ADS)

    Anderson, Jessica Thornley

    A Monte Carlo simulation is developed to study the performance of the closed-loop guidance, navigation, and control system of a lunar lander in powered descent. The simulation includes six-degrees-of-freedom dynamics, an extended Kalman filter, guidance based upon modified Apollo methods, an attitude control system, and several different types of sensors. Sensors included in the sensor suite include accelerometers, gyroscopes, a star camera, an altimeter, a velocimeter, and a radio navigation system. The simulation is used to examine the effects of sensor errors and the number of navigation states on total fuel use.

  16. Which type of fuel cell is more competitive for portable application: Direct methanol fuel cells or direct borohydride fuel cells?

    NASA Astrophysics Data System (ADS)

    Wee, Jung-Ho

    The promise of fuel cell systems using liquid fuels, such as the direct methanol fuel cell (DMFC) and direct borohydride fuel cell (DBFC), to complement or substitute for existing batteries is becoming recognized, along with their potential as a future technology for mobile and portable power supplies. The key issue is which type of fuel cell is more competitive for such power supplies: DMFC or DBFC? To answer this question, the present study analyzes and discusses the relative competitiveness of these two systems given the current status of the technologies and assuming some generally accepted conditions. The findings confirm that the DBFC system is superior to the DMFC system in terms of cell size and fuel (or fuel solution) consumption. Thus, the DBFC system is better suited to applications that require small operational space. On the other hand, the total operating costs of DBFC systems are higher than those of DMFC systems. According to the total cost formulae derived in the analysis, the DBFC system becomes relatively uneconomic at higher power outputs and longer operation times, but may be more favourable in specific portable applications such as miniaturized or micro power systems with short operational time spans.

  17. Thermal conductivities of U/sub 3/Si and U/sub 3/Si/sub 2/-Al dispersion fuels

    SciTech Connect

    Williams, R.K.; Graves, R.S.; Domagala, R.F.; Wiencek, T.C.

    1985-01-01

    Two high density uranium silicides are being evaluated as replacements for the research reactor fuels currently in use. Employing these compounds permits a major reduction in uranium enrichment, and tests have shown that the silicide fuels perform well under irradiation. Thermal conductivity data are required for analysis of these results and for safety calculations. The data show that silicide-Al dispersion fuels have somewhat better thermal conductivities than U/sub 3/O/sub 8/-Al dispersions, but their principal advantage is in their increased uranium content. The differences between the thermal conductivities of U/sub 3/Si and U/sub 3/Si/sub 2/ dispersions are small, but the microstructure of the dispersion was found to have a major influence on thermal conductivity. This seems to be associated with the formation of planar porosity defects during the roll bonding process, and differences as large as a factor of four (59 vs. 14 W/m . K) were noted for the samples having equal U/sub 3/Si/sub 2/ contents (46 v/o).

  18. Surface tension of Nanofluid-type fuels containing suspended nanomaterials

    PubMed Central

    2012-01-01

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension. PMID:22513039

  19. Pt nanoparticle-dispersed graphene-wrapped MWNT composites as oxygen reduction reaction electrocatalyst in proton exchange membrane fuel cell.

    PubMed

    Aravind, S S Jyothirmayee; Ramaprabhu, Sundara

    2012-08-01

    Chemical and electrical synergies between graphite oxide and multiwalled carbon nanotube (MWNT) for processing graphene wrapped-MWNT hybrids has been realized by chemical vapor deposition without any chemical functionalization. Potential of the hybrid composites have been demonstrated by employing them as electrocatalyst supports in proton exchange membrane fuel cells. The defects present in the polyelectrolyte, which have been wrapped over highly dispersed MWNT, act as anchoring sites for the homogeneous deposition of platinum nanoparticles. Single-cell proton exchange membrane fuel cells show that the power density of the hybrid composite-based fuel cells is higher compared to the pure catalyst-support-based fuel cells, because of enhanced electrochemical reactivity and good surface area of the nanocomposites. PMID:22850438

  20. High-Energy-Density Fuel Blending Strategies and Drop Dispersion for Fuel Cost Reduction and Soot Propensity Control

    NASA Technical Reports Server (NTRS)

    Bellan, J.; Harstad, K.

    1998-01-01

    The idea that low soot propensity of high-energy-density (HED) liquid sooting fuels and cost reduction of a multicomponent energetic fuel can be achieved by doping a less expensive, less sooting liquid fuel with HED is tested through numerical simulations.

  1. Scanning Electron Microscopy Analysis of Fuel/Matrix Interaction Layers in Highly-Irradiated U–Mo Dispersion Fuel Plates with Al and Al–Si Alloy Matrices

    SciTech Connect

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

    2014-04-01

    In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U–7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U–7Mo dispersion fuel elements with pure Al, Al–2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U–7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission-gas bubbles. Additionally, solid-fission-product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U–7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al–Si matrices.

  2. Color dispersion and Milky-Way-like reddening among type Ia supernovae

    SciTech Connect

    Scolnic, Daniel M.; Riess, Adam G.; Rodney, Steven A.; Brout, Dillon J.; Jones, David O.; Foley, Ryan J.; Rest, Armin

    2014-01-01

    Past analyses of Type Ia supernovae have identified an irreducible scatter of 5%-10% in distance, widely attributed to an intrinsic dispersion in luminosity. Another equally valid source of this scatter is intrinsic dispersion in color. Misidentification of the true source of this scatter can bias both the retrieved color-luminosity relation and cosmological parameter measurements. The size of this bias depends on the magnitude of the intrinsic color dispersion relative to the distribution of colors that correlate with distance. We produce a realistic simulation of a misattribution of intrinsic scatter and find a negative bias in the recovered color-luminosity relation, β, of Δβ ≈ –1.0 (∼33%) and a positive bias in the equation of state parameter, w, of Δw ≈ +0.04 (∼4%). We re-analyze current published datasets with the assumption that the distance scatter is predominantly the result of color. Unlike previous analyses, we find that the data are consistent with a Milky-Way-like reddening law (R{sub V} = 3.1) and that a Milky-Way dust model better predicts the asymmetric color-luminosity trends than the conventional luminosity scatter hypothesis. We also determine that accounting for color variation reduces the correlation between various host galaxy properties and Hubble residuals by ∼20%.

  3. Dispersing V-type asteroids during the planetary instability in the jumping Jupiter model

    NASA Astrophysics Data System (ADS)

    Brasil, P. I.

    2015-12-01

    V-type asteroids are a particular class of asteroids whose surface mineralogy is associated to a basaltic composition. Currently, the only known source of these asteroids in the Main Belt is (4) Vesta. This asteroid is located in the inner belt (2.1 < a < 2.5 AU), and has associated a dynamical family formed by the impact ejecta of two large craters excavated on its basaltic surface some 2 and 1 Gyr ago, respectively. Thus, many V-type asteroids belong to the Vesta family. However, an increasing number of V-type asteroids is found outside the limits of the family. Some of these asteroids, especially those located in the inner belt, are explained as dynamical fugitives from the family. Others cannot be linked to the Vesta family nor to (4) Vesta, neither dynamically nor mineralogically. The most paradoxal cases are the V-type asteroids found beyond 2.5 AU, in the central (2.5 < a < 2.8 AU) and outer (2.8 < a < 3.2 AU) parts of the Main Belt, where no local source of basaltic material is recognized. In this work, we propose a coherent dynamical mechanism to explain the delivery of V-type asteroids originated in the inner belt to the central and outer belt. This mechanism involves the planetary instability during the epoch when the outer planets were migrating due to their interaction with a disk of planetesimals, some 4 Gyr ago. The instability is caused by mutual planetary encounters in the framework of the jumping Jupiter model with initially five outer planets: Jupiter, Saturn and three ice giants. As a consequence of this instability, an ice giant is temporarily scattered into the asteroid belt and helps to disperse the asteroids in semimajor axis by up to ~0.5 AU. The V-type asteroids dispersed by this mechanism could have originated either in an older cratering event on the surface of (4) Vesta, or in the fragmentation of another basaltic asteroid in the inner belt that likely have existed during the epoch of planetary migration. We tested several

  4. Propagation of time-truncated Airy-type pulses in media with quadratic and cubic dispersion.

    PubMed

    Borda-Hernández, José A; Zamboni-Rached, Michel; Shaarawi, Amr; Besieris, Ioannis M

    2015-10-01

    In this paper, we describe analytically the propagation of Airy-type pulses truncated by a finite-time aperture when second- and third-order dispersion effects are considered. The mathematical method presented here, which is based on the superposition of exponentially truncated Airy pulses, is very effective and allows us to avoid the use of time-consuming numerical simulations. We analyze the behavior of the time-truncated ideal Airy pulse and also the interesting case of a time-truncated Airy pulse with a "defect" in its initial profile, which reveals the self-healing property of this kind of pulse solution. PMID:26479932

  5. Relative neutronic performance of proposed high-density dispersion fuels in water-moderated and D{sub 2}O-reflected research reactors

    SciTech Connect

    Bretscher, M.M.; Matos, J.E.; Snelgrove, J.L.

    1996-12-01

    This paper provides an overview of the neutronic performance of an idealized research reactor using several high density LEU fuels that are being developed by the RERTR program. High-density LEU dispersion fuels are needed for new and existing high-performance research reactors and to extend the lifetime of fuel elements in other research reactors. This paper discusses the anticipated neutronic behavior of proposed advanced fuels containing dispersions of U{sub 3}Si{sub 2}, UN, U{sub 2}Mo and several uranium alloys with Mo, or Zr and Nb. These advanced fuels are ranked based on the results of equilibrium depletion calculations for a simplified reactor model having a small H{sub 2}O-cooled core and a D{sub 2}O reflector. Plans have been developed to fabricate and irradiate several uranium alloy dispersion fuels in order to test their stability and compatibility with the matrix material and to establish practical loading limits.

  6. The DART dispersion analysis research tool: A mechanistic model for predicting fission-product-induced swelling of aluminum dispersion fuels. User`s guide for mainframe, workstation, and personal computer applications

    SciTech Connect

    Rest, J.

    1995-08-01

    This report describes the primary physical models that form the basis of the DART mechanistic computer model for calculating fission-product-induced swelling of aluminum dispersion fuels; the calculated results are compared with test data. In addition, DART calculates irradiation-induced changes in the thermal conductivity of the dispersion fuel, as well as fuel restructuring due to aluminum fuel reaction, amorphization, and recrystallization. Input instructions for execution on mainframe, workstation, and personal computers are provided, as is a description of DART output. The theory of fission gas behavior and its effect on fuel swelling is discussed. The behavior of these fission products in both crystalline and amorphous fuel and in the presence of irradiation-induced recrystallization and crystalline-to-amorphous-phase change phenomena is presented, as are models for these irradiation-induced processes.

  7. Investigation of Surfactant Type, Dosage and Ultrasonication Temperature Control on Dispersity of Metal-Coated Multi-Walled Carbon Nanotubes.

    PubMed

    Liang, Xiaoning; Li, Wei

    2016-04-01

    We studied the dispersity of multi-walled carbon nanotubes (MWNTs) combined with different metal- lic particles (Ni and Fe). An ultrasonic-assisted water-bath dispersion process was used to dis- perse the metal-coated MWNTs in different solutions and the dispersity was measured using an ultraviolet-visible spectrophotometer. The dispersity and morphology of the MWNTs were characterized using field-emission scanning electron microscopy (FE-SEM) together with digital image processing technology. Effects of dispersant type (sodium dodecyl benzene sulfonate (SDBS), oleic acid, and polymer (TNEDIS)) and surfactant dosage on the dispersity of the metal-coated MWNTs were investigated under controlled and uncontrolled temperatures and results were compared with those from the untreated MWNTs. The results showed that the negative effects of temperature on the ultrasonic dispersion process could be eliminated through a temperature-controlled system. Moreover, the TNEDIS, SDBS, and oleic acid were arranged in the descending order of the dispersion effect degree. The untreated MWNTs, Ni-coated MWNTs, and Fe-coated MWNTs were arranged in the descending degree of dispersity order. Since the metal coating makes the MWNTs harder and more fragile, the metal-coated MWNTs are more likely to fracture during the ultrasonic dispersion process. PMID:27451790

  8. Asymmetric transmission in prisms using structures and materials with isotropic-type dispersion.

    PubMed

    Gundogdu, Funda Tamara; Serebryannikov, Andriy E; Cakmak, A Ozgur; Ozbay, Ekmel

    2015-09-21

    It is demonstrated that strong asymmetry in transmission can be obtained at the Gaussian beam illumination for a single prism based on a photonic crystal (PhC) with isotropic-type dispersion, as well as for its analog made of a homogeneous material. Asymmetric transmission can be realized with the aid of refraction at a proper orientation of the interfaces and wedges of the prism, whereas neither contribution of higher diffraction orders nor anisotropic-type dispersion is required. Furthermore, incidence toward a prism wedge can be used for one of two opposite directions in order to obtain asymmetry. Thus, asymmetric transmission is a general property of the prism configurations, which can be obtained by using simple geometries and quite conventional materials. The obtained results show that strong asymmetry can be achieved in PhC prisms with (nearly) circular shape of equifrequency dispersion contours, in both cases associated with the index of refraction 01. For the comparison purposes, results are also presented for solid uniform non-magnetic prisms made of a material with the same value of n. It is shown in zero-loss approximation that the PhC prism and the ultralow-index material prism (01. Possible contributions of scattering on the individual rods and diffraction on the wedge to the resulting mechanism are discussed. Analogs of unidirectional splitting and unidirectional deflection regimes, which are known from the studies of PhC gratings, are obtained in PhC prisms and solid uniform prisms, i.e. without higher diffraction orders. PMID:26406618

  9. First Results of Scanning Thermal Diffusivity Microscope (STDM) Measurements on Irradiated Monolithic and Dispersion Fuel

    SciTech Connect

    T. K. Huber; M. K. Figg; J. R. Kennedy; A. B. Robinson; D. M. Wachs

    2012-07-01

    The thermal conductivity of the fuel material in a reactor before and during irradiation is a sensitive and fundamental parameter for thermal hydraulic calculations that are useds to correctly determine fuel heat fluxes and meat temperatures and to simulate performance of the fuel elements during operation. Several techniques have been developed to measure the thermal properties of fresh fuel to support these calculations, but it is crucial to also investigate the change of thermal properties during irradiation.

  10. Effects of Irradiation on the Microstructure of U-7Mo Dispersion Fuel with Al-2Si Matrix

    SciTech Connect

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Adam B. Robinson; Pavel Medvedev; Jian Gan; Brandon D. Miller; Daniel M. Wachs; Glenn A. Moore; Curtis R. Clark; Mitchell K. Meyer; M. Ross Finlay

    2012-06-01

    The Reduced Enrichment for Research and Test Reactor program is developing low-enriched uranium U-Mo dispersion fuels for application in research and test reactors around the world. As part of this development, fuel plates have been irradiated in the Advanced Test Reactor and then characterized using optical metallography (OM) and scanning electron microscopy (SEM) to determine the as-irradiated microstructure. To demonstrate the irradiation performance of U-7Mo dispersion fuel plates with 2 wt% Si added to the matrix, fuel plates were tested to medium burnups at intermediate fission rates as part of the RERTR-6 experiment. Further testing was performed to higher fission rates as part of the RERTR-7A experiment, and very aggressive testing (high temperature, high fission density, high fission rate) was performed in the RERTR-9A, RERTR-9B and AFIP-1 experiments. As-irradiated microstructures were compared to those observed after fabrication to determine the effects of irradiation on the microstructure. Based on comparison of the microstructural characterization results for each irradiated sample, some general conclusions can be drawn about how the microstructure evolves during irradiation: there is growth of the fuel/matrix interaction layer (FMI), which was present in the samples to some degree after fabrication, during irradiation; Si diffuses from the FMI layer to deeper depths in the U-7Mo particles as the irradiation conditions are made more aggressive; lowering of the Si content in the FMI layer results in an increase in the size of the fission gas bubbles; as the FMI layer grows during irradiation more Si diffuses from the matrix to the FMI layer/matrix interface, and interlinking of fission gas bubbles in the fuel plate microstructure that may indicate breakaway swelling is not observed.

  11. Preparation of highly dispersed core/shell-type titania nanocapsules containing a single Ag nanoparticle.

    PubMed

    Sakai, Hideki; Kanda, Takashi; Shibata, Hirobumi; Ohkubo, Takahiro; Abe, Masahiko

    2006-04-19

    Core/shell-type titania nanocapsules containing a single Ag nanoparticle were prepared. Ag nanoparticles were prepared using the reduction of silver nitrate with hydrazine in the presence of cetyltrimethylammonium bromide (CTAB) as protective agent. The sol-gel reaction of titanium tetraisopropoxide (TTIP) was used to prepare core/shell-type titania nanocapsules with CTAB-coated Ag nanoparticles as the core. TEM observations revealed that the size of the core (Ag particle) and the thickness of the shell (titania) of the core/shell particles obtained are about 10 nm and 5-10 nm, respectively. In addition, the nanocapsules were found to be dispersed in the medium as individual particles without aggregation. Moreover, titania coating caused the surface plasmon absorption of Ag nanoparticles to shift toward the longer wavelength side. PMID:16608315

  12. Dispersant Effectiveness Of Heavy Fuel Oils Using The Baffled Flask Test

    EPA Science Inventory

    Dispersants have been widely used as a primary response measure for marine oil spills around the world. Recently, the U.S. Environmental Protection Agency (EPA) developed an improved laboratory dispersant testing protocol, called the Baffled Flask Test (BFT). The BFT protocol w...

  13. Use of Stable Noble Gases as a Predictor of Reactor Fuel Type and Exposure

    SciTech Connect

    Fearey, B.L.; Charlton, W.S.; Perry, R.T.; Poths, J.; Wilson, W.B.; Hemberger, P.H.; Nakhleh, C.W.; Stanbro, W.D.

    1999-08-30

    Ensuring spent reactor fuel is not produced to provide weapons-grade plutonium is becoming a major concern as many countries resort to nuclear power as a solution to their energy problems. Proposed solutions range from the development of proliferation resistant fuel to continuous monitoring of the fuel. This paper discusses the use of the stable isotopes of the fissiogenic noble gases, xenon and krypton, for determining the burnup characteristics, fuel type, and the reactor type of the fuel from which the sample was obtained. The gases would be collected on-stack as the fuel is reprocessed, and thus confirm that the fuel is as declared.

  14. Fuel swelling and interaction layer formation in the SELENIUM Si and ZrN coated U(Mo) dispersion fuel plates irradiated at high power in BR2

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van den Berghe, S.; Koonen, E.; Kuzminov, V.; Detavernier, C.

    2015-03-01

    In the framework of the SELENIUM project two full size flat fuel plates were produced with respectively Si and ZrN coated U(Mo) particles and irradiated in the BR2 reactor at SCK•CEN. Non-destructive analysis of the plates showed that the fuel swelling profiles of both SELENIUM plates were very similar to each other and none of the plates showed signs of pillowing or excessive swelling at the end of irradiation at the highest power position (local maximum 70% 235U). The microstructural analysis showed that the Si coated fuel has less interaction phase formation at low burn-up but at the highest burn-ups, defects start to develop on the IL-matrix interface. The ZrN coated fuel, shows a virtual absence of reaction between the U(Mo) and the Al, up to high fission densities after which the interaction layer formation starts and defects develop in the matrix near the U(Mo) particles. It was found and is confirmed by the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) experiment that there are two phenomena at play that need to be controlled: the formation of an interaction layer and swelling of the fuel. As the interaction layer formation occurs at the U(Mo)-matrix interface, applying a diffusion barrier (coating) at that interface should prevent the interaction between U(Mo) and the matrix. The U(Mo) swelling, observed to proceed at an accelerating rate with respect to fission density accumulation, is governed by linear solid state swelling and fission gas bubble swelling due to recrystallization of the fuel. The examination of the SELENIUM fuel plates clearly show that for the U(Mo) dispersion fuel to be qualified, the swelling rate at high burn-up needs to be reduced.

  15. FINITE ELEMENT SIMULATION FOR STRUCTURAL RESPONSE OF U7MO DISPERSION FUEL PLATES VIA FLUID-THERMAL-STRUCTURAL INTERACTION

    SciTech Connect

    Hakan Ozaltun; Herman Shen; Pavel Madvedev

    2010-11-01

    This article presents numerical simulation of dispersion fuel mini plates via fluid–thermal–structural interaction performed by commercial finite element solver COMSOL Multiphysics to identify initial mechanical response under actual operating conditions. Since fuel particles are dispersed in Aluminum matrix, and temperatures during the fabrication process reach to the melting temperature of the Aluminum matrix, stress/strain characteristics of the domain cannot be reproduced by using simplified models and assumptions. Therefore, fabrication induced stresses were considered and simulated via image based modeling techniques with the consideration of the high temperature material data. In order to identify the residuals over the U7Mo particles and the Aluminum matrix, a representative SEM image was employed to construct a microstructure based thermo-elasto-plastic FE model. Once residuals and plastic strains were identified in micro-scale, solution was used as initial condition for subsequent multiphysics simulations at the continuum level. Furthermore, since solid, thermal and fluid properties are temperature dependent and temperature field is a function of the velocity field of the coolant, coupled multiphysics simulations were considered. First, velocity and pressure fields of the coolant were computed via fluidstructural interaction. Computed solution for velocity fields were used to identify the temperature distribution on the coolant and on the fuel plate via fluid-thermal interaction. Finally, temperature fields and residual stresses were used to obtain the stress field of the plates via fluid-thermal-structural interaction.

  16. Observations of four types of pulses in a fiber laser with large net-normal dispersion.

    PubMed

    Wang, Leiran; Liu, Xueming; Gong, Yongkang; Mao, Dong; Duan, Lina

    2011-04-11

    Four different types of pulses are experimentally obtained in one erbium-doped all-fiber laser with large net-normal dispersion. The proposed laser can deliver the rectangular-spectrum (RS), Gaussian-spectrum (GS), broadband-spectrum (BS), and noise-like pulses by appropriately adjusting the polarization states. These kinds of pulses have distinctly different characteristics. The RS pulses can easily be compressed to femtosecond level whereas the pulse energy is restricted by the trend of multi-pulse shaping with excessive pump. The GS and BS pulses always maintain the single-pulse operation with much higher pulse-energy and accumulate much more chirp. After launching the pulses into the photonic-crystal fiber, the supercontinuum can be generated with the bandwidth of >700 nm by the BS pulses and of ~400 nm by the GS pulses, whereas it can hardly be generated by the RS pulses. The physical mechanisms behind the continuum generation are qualitatively investigated relating to different operating regimes. This work could help to a deeper insight of the normal-dispersion pulses. PMID:21503070

  17. The crossing statistic: dealing with unknown errors in the dispersion of Type Ia supernovae

    SciTech Connect

    Shafieloo, Arman; Clifton, Timothy; Ferreira, Pedro E-mail: tclifton@astro.ox.ac.uk

    2011-08-01

    We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: The Crossing Statistic. This statistic is in general less sensitive than χ{sup 2} to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the χ{sup 2} statistic fails. We also show that the last mode of the Crossing Statistic is identical to χ{sup 2}, so that it can be considered as a generalization of χ{sup 2}.

  18. 40 CFR 600.207-93 - Calculation of fuel economy values for a model type.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... a model type. 600.207-93 Section 600.207-93 Protection of Environment ENVIRONMENTAL PROTECTION... Economy Regulations for 1977 and Later Model Year Automobiles-Procedures for Calculating Fuel Economy Values § 600.207-93 Calculation of fuel economy values for a model type. (a) Fuel economy values for...

  19. High burn-up structure of U(Mo) dispersion fuel

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van Renterghem, W.; Van den Berghe, S.

    2016-08-01

    The evolution of the high burn-up structure (HBS) in U(Mo) fuel irradiated up to a burn-up of ∼70% 235U or ∼5 × 1021 f/cm3 or ∼120 GWd/tHM is described and compared to the observation made on LWR fuel. Scanning and transmission electron microscopy was performed on several samples having different burn-ups in order to get a better understanding of the mechanisms leading to the high burn-up structure formation. Even though there are some substantial differences between the irradiation of ceramic and U(Mo) alloy fuels (crystal structure, enrichment, irradiation temperature …), it was found that in both fuels recrystallization initiates at the same threshold and progresses in a similar way with increasing fission density. In case of U(Mo), recrystallization leads to accelerated swelling of the fuel which could result in instability of the fuel plate.

  20. Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

    NASA Astrophysics Data System (ADS)

    Feddema, Rick

    Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

  1. Swelling of U-7Mo/Al-Si dispersion fuel plates under irradiation - Non-destructive analysis of the AFIP-1 fuel plates

    NASA Astrophysics Data System (ADS)

    Wachs, D. M.; Robinson, A. B.; Rice, F. J.; Kraft, N. C.; Taylor, S. C.; Lillo, M.; Woolstenhulme, N.; Roth, G. A.

    2016-08-01

    Extensive fuel-matrix interactions leading to plate pillowing have proven to be a significant impediment to the development of a suitable high density low-enriched uranium molybdenum alloy (U-Mo) based dispersion fuel for high power applications in research reactors. The addition of silicon to the aluminum matrix was previously demonstrated to reduce interaction layer growth in mini-plate experiments. The AFIP-1 project involved the irradiation, in-canal examination, and post-irradiation examination of two fuel plates. The irradiation of two distinct full size, flat fuel plates (one using an Al-2wt%Si matrix and the other an Al-4043 (∼4.8 wt% Si) matrix) was performed in the INL ATR reactor in 2008-2009. The irradiation conditions were: ∼250 W/cm2 peak Beginning Of Life (BOL) power, with a ∼3.5e21 f/cm3 peak burnup. The plates were successfully irradiated and did not show any pillowing at the end of the irradiation. This paper reports the results and interpretation of the in-canal and post-irradiation non-destructive examinations that were performed on these fuel plates. It further compares additional PIE results obtained on fuel plates irradiated in contemporary campaigns in order to allow a complete comparison with all results obtained under similar conditions. Except for a brief indication of accelerated swelling early in the irradiation of the Al-2Si plate, the fuel swelling is shown to evolve linearly with the fission density through the maximum burnup.

  2. Estimation of the dispersion of an accidental release of radionuclides and toxic materials based on weather type classification

    NASA Astrophysics Data System (ADS)

    Mészáros, Róbert; Leelőssy, Ádám; Vincze, Csilla; Szűcs, Mihály; Kovács, Tibor; Lagzi, István

    2012-02-01

    We investigate the influence of the regional-scale weather types on the atmospheric dispersion processes of the air pollutants originated from point sources. Hypothetical accidents were simulated with two different dispersion models. During a year's test period, the 6-h emission of a radionuclide from the Paks Nuclear Power Plant (Paks NPP, Hungary) was assumed every day and the transport and deposition of the radionuclide was simulated by the Eulerian TREX dispersion model over the Central European region. In addition, the ALOHA Gaussian air dispersion model was also used for the local environment of the Paks NPP to simulate hypothetical hourly releases of ammonia during a 10-year period. During both types of model simulations, the dispersion of the plume for each time was analysed and tested with consideration of 13 circulation types corresponding to daily weather patterns over the Carpathian Basin. There are significant correlations between circulation types and plume directions and structures both in local and regional scales. The daily circulation pattern can be easily obtained from weather analyses; the expected size and direction of polluted area after an accidental release can be quickly estimated even before an accident occurs. However, this fast method cannot replace or neglect dispersion model simulations. It gives a `first guess' and a fast estimation on the direction of the plume and can provide sufficient information for decision-making strategies.

  3. Cosmic Evolution of Size and Velocity Dispersion for Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, L.; Lapi, A.; Bressan, A.; Bernardi, M.; De Zotti, G.; Danese, L.

    2010-08-01

    Massive (stellar mass M sstarf >~ 3 × 1010 M sun), passively evolving galaxies at redshifts z >~ 1 exhibit on average physical sizes smaller, by factors ≈3, than local early-type galaxies (ETGs) endowed with the same stellar mass. Small sizes are in fact expected on theoretical grounds, if dissipative collapse occurs. Recent results show that the size evolution at z <~ 1 is limited to less than 40%, while most of the evolution occurs at z >~ 1, where both compact and already extended galaxies are observed and the scatter in size is remarkably larger than it is locally. The presence at high redshift of a significant number of ETGs with the same size as their local counterparts, as well as ETGs with quite small size (lsim1/10 of the local one), points to a timescale for reaching the new, expanded equilibrium configuration of less than the Hubble time tH (z). We demonstrate that the projected mass of compact, high-redshift galaxies and that of local ETGs within the same physical radius, the nominal half-luminosity radius of high-redshift ETGs, differ substantially in that the high-redshift ETGs are on average significantly denser. This result suggests that the physical mechanism responsible for the size increase should also remove mass from central galaxy regions (r <~ 1 kpc). We propose that quasar activity, which peaks at redshift z ~ 2, can remove large amounts of gas from central galaxy regions on a timescale shorter than the triggering a puffing up of the stellar component at constant stellar mass (or a timescale on the order of the dynamical one); in this case, the size increase goes together with a decrease in the central mass. The size evolution is expected to parallel that of the quasars and the inverse hierarchy, or downsizing, seen in the quasar evolution is mirrored in the size evolution. Exploiting the virial theorem, we derive the relation between the stellar velocity dispersion of ETGs and the characteristic velocity of their hosting halos at the

  4. Effect of palladium dispersion on the capture of toxic components from fuel gas by palladium-alumina sorbents

    SciTech Connect

    Baltrus, John P.; Granite, Evan J.; Rupp, Erik C.; Stanko, Dennis C.; Howard, Bret; Pennline, Henry W.

    2011-05-01

    The dispersion and location of Pd in alumina-supported sorbents prepared by different methods was found to influence the performance of the sorbents in the removal of mercury, arsine, and hydrogen selenide from a simulated fuel gas. When Pd is well dispersed in the pores of the support, contact interaction with the support is maximized, Pd is less susceptible to poisoning by sulfur, and the sorbent has better long-term activity for adsorption of arsine and hydrogen selenide, but poorer adsorption capacity for Hg. As the contact interaction between Pd and the support is lessened the Pd becomes more susceptible to poisoning by sulfur, resulting in higher capacity for Hg, but poorer long-term performance for adsorption of arsenic and selenium.

  5. Effect of palladium dispersion on the capture of toxic components from fuel gas by palladium-alumina sorbents

    SciTech Connect

    Baltrus, J.P.; Granite, E.J.; Rupp, E.C.; Stanko, D.C.; Howard, B.; Pennline, H.W.

    2011-01-01

    The dispersion and location of Pd in alumina-supported sorbents prepared by different methods was found to influence the performance of the sorbents in the removal of mercury, arsine, and hydrogen selenide from a simulated fuel gas. When Pd is well dispersed in the pores of the support, contact interaction with the support is maximized, Pd is less susceptible to poisoning by sulfur. and the sorbent has better long-term activity for adsorption of arsine and hydrogen selenide. but poorer adsorption capacity for Hg. As the contact interaction between Pd and the support is lessened the Pd becomes more susceptible to poisoning by sulfur. resulting in higher capacity for Hg, but poorer long-term performance for adsorption of arsenic and selenium.

  6. Highly bendable bilayer-type photo-actuators comprising of reduced graphene oxide dispersed in hydrogels

    PubMed Central

    Kim, Dowan; Lee, Heon Sang; Yoon, Jinhwan

    2016-01-01

    To avoid the problem of reduced graphene oxide (rGO) restacking in aqueous solution, the preparation of light-responsive poly(N-isopropylacrylamide) incorporating rGO (PNIPAm/rGO) was achieved by the chemical reduction of GO dispersed in the hydrogel matrix. Due to the enhanced photothermal efficiency of the rGO, the prepared PNIPAm/rGO underwent large volume reductions in response to irradiation by visible light of modest intensity. With respect to potential applications, bilayer-type photo-actuators comprising a PNIPAm/rGO active layer and poly(acrylamide) passive layer were fabricated; these achieved a full bending motion upon visible-light exposure. Adjusting the swelling ratio of each layer in the initial state yielded bidirectional photo-actuators that showed the active motion of turning inside out. Furthermore, we demonstrated that the fabricated actuation system would exhibit controlled bending motion in response to solar radiation. PMID:26865239

  7. Highly bendable bilayer-type photo-actuators comprising of reduced graphene oxide dispersed in hydrogels

    NASA Astrophysics Data System (ADS)

    Kim, Dowan; Lee, Heon Sang; Yoon, Jinhwan

    2016-02-01

    To avoid the problem of reduced graphene oxide (rGO) restacking in aqueous solution, the preparation of light-responsive poly(N-isopropylacrylamide) incorporating rGO (PNIPAm/rGO) was achieved by the chemical reduction of GO dispersed in the hydrogel matrix. Due to the enhanced photothermal efficiency of the rGO, the prepared PNIPAm/rGO underwent large volume reductions in response to irradiation by visible light of modest intensity. With respect to potential applications, bilayer-type photo-actuators comprising a PNIPAm/rGO active layer and poly(acrylamide) passive layer were fabricated; these achieved a full bending motion upon visible-light exposure. Adjusting the swelling ratio of each layer in the initial state yielded bidirectional photo-actuators that showed the active motion of turning inside out. Furthermore, we demonstrated that the fabricated actuation system would exhibit controlled bending motion in response to solar radiation.

  8. Estimating canopy fuel parameters for Atlantic Coastal Plain forest types.

    SciTech Connect

    Parresol, Bernard, R.

    2007-01-15

    Abstract It is necessary to quantify forest canopy characteristics to assess crown fire hazard, prioritize treatment areas, and design treatments to reduce crown fire potential. A number of fire behavior models such as FARSITE, FIRETEC, and NEXUS require as input four particular canopy fuel parameters: 1) canopy cover, 2) stand height, 3) crown base height, and 4) canopy bulk density. These canopy characteristics must be mapped across the landscape at high spatial resolution to accurately simulate crown fire. Currently no models exist to forecast these four canopy parameters for forests of the Atlantic Coastal Plain, a region that supports millions of acres of loblolly, longleaf, and slash pine forests as well as pine-broadleaf forests and mixed species broadleaf forests. Many forest cover types are recognized, too many to efficiently model. For expediency, forests of the Savannah River Site are categorized as belonging to 1 of 7 broad forest type groups, based on composition: 1) loblolly pine, 2) longleaf pine, 3) slash pine, 4) pine-hardwood, 5) hardwood-pine, 6) hardwoods, and 7) cypress-tupelo. These 7 broad forest types typify forests of the Atlantic Coastal Plain region, from Maryland to Florida.

  9. Potential Annealing Treatments for Tailoring the Starting Microstructure of Low-Enriched U-Mo Dispersion Fuels to Optimize Performance During Irradiation

    SciTech Connect

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Nicolas E. Woolstenhulme; Ashley Ewh

    2011-12-01

    Low-enriched uranium-molybdenum alloy particles dispersed in aluminum alloy (e.g., dispersion fuels) are being developed for application in research and test reactors. To achieve the best performance of these fuels during irradiation, optimization of the starting microstructure may be required by utilizing a heat treatment that results in the formation of uniform, Si-rich interaction layers between the U-Mo particles and Al-Si matrix. These layers behave in a stable manner under certain irradiation conditions. To identify the optimum heat treatment for producing these kinds of layers in a dispersion fuel plate, a systematic annealing study has been performed using actual dispersion fuel samples, which were fabricated at relatively low temperatures to limit the growth of any interaction layers in the samples prior to controlled heat treatment. These samples had different Al matrices with varying Si contents and were annealed between 450 and 525 C for up to 4 hours. The samples were then characterized using scanning electron microscopy (SEM) to examine the thickness, composition, and uniformity of the interaction layers. Image analysis was performed to quantify various attributes of the dispersion fuel microstructures that related to the development of the interaction layers. The most uniform layers were observed to form in fuel samples that had an Al matrix with at least 4 wt% Si and a heat treatment temperature of at least 475 C.

  10. Alternative diesel fuel study on four different types of vegetable oils of Turkish origin

    SciTech Connect

    Oezaktas, T.; Cigizoglu, K.B.; Karaosmanoglu, F.

    1997-02-01

    Four different types of vegetable oils of Turkish origin (sunflower, corn, soybean, and olive oil) were blended with grade 2-D diesel fuel at a ratio of 20/80 (v/v). Blends were investigated in a diesel engine with a precombustion chamber at speeds between 1,200 and 2,100 rpm. Vegetable oils, diesel fuel, and fuel blends were characterized according to standard test methods. It was found that for short-term use, the fuel blends have engine characteristics similar to the baseline diesel fuel. Fuel blends also display less smoke emissions than diesel fuel.

  11. Transmission electron microscopy characterization of the fission gas bubble superlattice in irradiated U-7wt% Mo dispersion fuels

    SciTech Connect

    B.D. Miller; J. Gan; D.D. Keiser Jr.; A.B. Robinson; J.-F. Jue; J.W. Madden; P.G. Medvedev

    2015-03-01

    Transmission electron microscopy characterization of irradiated U-7wt% Mo dispersion fuel was performed on various samples to understand the effect of irradiation parameters (fission density, fission rate, and temperature) on the self-organized fission-gas-bubble superlattice that forms in the irradiated U-Mo fuel. The bubble superlattice was seen to form a face-centered cubic structure coherent with the host U-7wt% Mo body centered cubic structure. At a fission density between 3.0 and 4.5 x 1021 fiss/cm3, the superlattice bubbles appear to have reached a saturation size with additional fission gas associated with increasing burnup predominately accumulating along grain boundaries. At a fission density of ~4.5x1021 fiss/cm3, the U-7wt% Mo microstructure undergoes grain subdivision and can no longer support the ordered bubble superlattice. The fuel grains are primarily less than 500 nm in diameter with micron-size fission-gas bubbles present on the grain boundaries. Solid fission products decorate the inside surface of the micron-sized fission-gas bubbles. Residual superlattice bubbles are seen in areas where fuel grains remain micron sized. Potential mechanisms of the formation and collapse of the bubble superlattice are discussed.

  12. Modeling the Integrated Performance of Dispersion and Monolithic U-Mo Based Fuels

    SciTech Connect

    Daniel M. Wachs; Douglas E. Burkes; Steven L. Hayes; Karen Moore; Greg Miller; Gerard Hofman; Yeon Soo Kim

    2006-10-01

    The evaluation and prediction of integrated fuel performance is a critical component of the Reduced Enrichment for Research and Test Reactors (RERTR) program. The PLATE code is the primary tool being developed and used to perform these functions. The code is being modified to incorporate the most recent fuel/matrix interaction correlations as they become available for both aluminum and aluminum/silicon matrices. The code is also being adapted to treat cylindrical and square pin geometries to enhance the validation database by including the results gathered from various international partners. Additional modeling work has been initiated to evaluate the thermal and mechanical performance requirements unique to monolithic fuels during irradiation.

  13. Verifying the Cosmological Utility of Type Ia Supernovae: Implications of a Dispersion in the Ultraviolet Spectra

    SciTech Connect

    Nugent, Peter E; Ellis, R.S.; Sullivan, M.; Nugent, P.E.; Howell, D.A.; Gal-Yam, A.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; Carlberg, R.; Conley, A.; Fouchez, D.; Guy, J.; Hardin, D.; Hook, I.; Pain, R.; Perrett, K.; Pritchet, C.J.; Regnault, N.

    2008-02-28

    We analyze the mean rest-frame ultraviolet (UV) spectrum of Type Ia Supernovae (SNe) and its dispersion using high signal-to-noise ratio Keck-I/LRIS-B spectroscopy for a sample of 36 events at intermediate redshift (z=0.5) discovered by the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We introduce a new method for removing host galaxy contamination in our spectra, exploiting the comprehensive photometric coverage of the SNLS SNe and their host galaxies, thereby providing the first quantitative view of the UV spectral properties of a large sample of distant SNe Ia. Although the mean SN Ia spectrum has not evolved significantly over the past 40percent of cosmic history, precise evolutionary constraints are limited by the absence of a comparable sample of high-quality local spectra. The mean UV spectrum of our z~;;=0.5 SNe Ia and its dispersion is tabulated for use in future applications. Within the high-redshift sample, we discover significant UV spectral variations and exclude dust extinction as the primary cause by examining trends with the optical SN color. Although progenitor metallicity may drive some of these trends, the variations we see are much larger than predicted in recent models and do not follow expected patterns. An interesting new result is a variation seen in the wavelength of selected UV features with phase. We also demonstrate systematic differences in the SN Ia spectral features with SN light curve width in both the UV and the optical. We show that these intrinsic variations could represent a statistical limitation in the future use of high-redshift SNe Ia for precision cosmology. We conclude that further detailed studies are needed, both locally and at moderate redshift where the rest-frame UV can be studied precisely, in order that future missions can confidently be planned to fully exploit SNe Ia as cosmological probes.

  14. Spent fuel sabotage test program, characterization of aerosol dispersal : technical review and analysis supplement.

    SciTech Connect

    Durbin, Samuel G.; Lindgren, Eric Richard

    2009-07-01

    This project seeks to provide vital data required to assess the consequences of a terrorist attack on a spent fuel transportation cask. One such attack scenario involves the use of conical shaped charges (CSC), which are capable of damaging a spent fuel transportation cask. In the event of such an attack, the amount of radioactivity that may be released as respirable aerosols is not known with great certainty. Research to date has focused on measuring the aerosol release from single short surrogate fuel rodlets subjected to attack by a small CSC device in various aerosol chamber designs. The last series of three experiments tested surrogate fuel rodlets made with depleted uranium oxide ceramic pellets in a specially designed double chamber aerosol containment apparatus. This robust testing apparatus was designed to prevent any radioactive release and allow high level radioactive waste disposal of the entire apparatus following testing of actual spent fuel rodlets as proposed. DOE and Sandia reviews of the project to date identified a number of issues. The purpose of this supplemental report is to address and document the DOE review comments and to resolve the issues identified in the Sandia technical review.

  15. 27 CFR 19.685 - Change in type of alcohol fuel plant.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... fuel plant. 19.685 Section 19.685 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Changes to Permit Information § 19.685 Change in type of alcohol fuel plant. (a) Small plants. If...

  16. 27 CFR 19.685 - Change in type of alcohol fuel plant.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... fuel plant. 19.685 Section 19.685 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Changes to Permit Information § 19.685 Change in type of alcohol fuel plant. (a) Small plants. If...

  17. 40 CFR 600.207-86 - Calculation of fuel economy values for a model type.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Calculation of fuel economy values for a model type. 600.207-86 Section 600.207-86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy Regulations for 1977 and Later...

  18. 41 CFR 102-34.325 - What type of fuel do I use in Government motor vehicles?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...; or (2) Such gasoline is not available locally. (c) You must use alternative fuels in alternative fuel... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false What type of fuel do I... PROPERTY 34-MOTOR VEHICLE MANAGEMENT Motor Vehicle Fueling § 102-34.325 What type of fuel do I use...

  19. 41 CFR 102-34.325 - What type of fuel do I use in Government motor vehicles?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; or (2) Such gasoline is not available locally. (c) You must use alternative fuels in alternative fuel... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false What type of fuel do I... PROPERTY 34-MOTOR VEHICLE MANAGEMENT Motor Vehicle Fueling § 102-34.325 What type of fuel do I use...

  20. 41 CFR 102-34.325 - What type of fuel do I use in Government motor vehicles?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; or (2) Such gasoline is not available locally. (c) You must use alternative fuels in alternative fuel... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What type of fuel do I... PROPERTY 34-MOTOR VEHICLE MANAGEMENT Motor Vehicle Fueling § 102-34.325 What type of fuel do I use...

  1. Method and device for fabricating dispersion fuel comprising fission product collection spaces

    SciTech Connect

    Shaber, Eric L; Fielding, Randall S

    2015-05-05

    A method of fabricating a nuclear fuel comprising a fissile material, one or more hollow microballoons, a phenolic resin, and metal matrix. The fissile material, phenolic resin and the one or more hollow microballoons are combined. The combined fissile material, phenolic resin and the hollow microballoons are heated sufficiently to form at least some fissile material carbides creating a nuclear fuel particle. The resulting nuclear fuel particle comprises one or more fission product collection spaces. In a preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by forming the fissile material into microspheres. The fissile material microspheres are then overcoated with the phenolic resin and microballoon. In another preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by overcoating the microballoon with the fissile material, and phenolic resin.

  2. Metacommunity structuring in stream networks: roles of dispersal mode, distance type, and regional environmental context

    PubMed Central

    Grönroos, Mira; Heino, Jani; Siqueira, Tadeu; Landeiro, Victor L; Kotanen, Juho; Bini, Luis M

    2013-01-01

    Within a metacommunity, both environmental and spatial processes regulate variation in local community structure. The strength of these processes may vary depending on species traits (e.g., dispersal mode) or the characteristics of the regions studied (e.g., spatial extent, environmental heterogeneity). We studied the metacommunity structuring of three groups of stream macroinvertebrates differing in their overland dispersal mode (passive dispersers with aquatic adults; passive dispersers with terrestrial adults; active dispersers with terrestrial adults). We predicted that environmental structuring should be more important for active dispersers, because of their better ability to track environmental variability, and that spatial structuring should be more important for species with aquatic adults, because of stronger dispersal limitation. We sampled a total of 70 stream riffle sites in three drainage basins. Environmental heterogeneity was unrelated to spatial extent among our study regions, allowing us to examine the effects of these two factors on metacommunity structuring. We used partial redundancy analysis and Moran's eigenvector maps based on overland and watercourse distances to study the relative importance of environmental control and spatial structuring. We found that, compared with environmental control, spatial structuring was generally negligible, and it did not vary according to our predictions. In general, active dispersers with terrestrial adults showed stronger environmental control than the two passively dispersing groups, suggesting that the species dispersing actively are better able to track environmental variability. There were no clear differences in the results based on watercourse and overland distances. The variability in metacommunity structuring among basins was not related to the differences in the environmental heterogeneity and spatial extent. Our study emphasized that (1) environmental control is prevailing in stream metacommunities

  3. In-pile test results of U-silicide or U-nitride coated U-7Mo particle dispersion fuel in Al

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Park, J. M.; Lee, K. H.; Yoo, B. O.; Ryu, H. J.; Ye, B.

    2014-11-01

    U-silicide or U-nitride coated U-Mo particle dispersion fuel in Al (U-Mo/Al) was in-pile tested to examine the effectiveness of the coating as a diffusion barrier between the U-7Mo fuel kernels and Al matrix. This paper reports the PIE data and analyses focusing on the effectiveness of the coating in terms of interaction layer (IL) growth and general fuel performance. The U-silicide coating showed considerable success, but it also provided evidence for additional improvement for coating process. The U-nitride coated specimen showed largely inefficient results in reducing IL growth. From the test, important observations were also made that can be utilized to improve U-Mo/Al fuel performance. The heating process for coating turned out to be beneficial to suppress fuel swelling. The use of larger fuel particles confirmed favorable effects on fuel performance.

  4. Microcalorimeter-type energy dispersive X-ray spectrometer for a transmission electron microscope.

    PubMed

    Hara, Toru; Tanaka, Keiichi; Maehata, Keisuke; Mitsuda, Kazuhisa; Yamasaki, Noriko Y; Ohsaki, Mitsuaki; Watanabe, Katsuaki; Yu, Xiuzhen; Ito, Takuji; Yamanaka, Yoshihiro

    2010-01-01

    A new energy dispersive X-ray spectrometer (EDS) with a microcalorimeter detector equipped with a transmission electron microscope (TEM) has been developed for high- accuracy compositional analysis in the nanoscale. A superconducting transition-edge-sensor-type microcalorimeter is applied as the detector. A cryogen-free cooling system, which consists of a mechanical and a dilution refrigerator, is selected to achieve long-term temperature stability. In order to mount these detector and refrigerators on a TEM, the cooling system is specially designed such that these two refrigerators are separated. Also, the detector position and arrangement are carefully designed to avoid adverse affects between the superconductor detector and the TEM lens system. Using the developed EDS system, at present, an energy resolution of 21.92 eV full-width-at-half maximum has been achieved at the Cr K alpha line. This value is about seven times better than that of the current typical commercial Si(Li) detector, which is usually around 140 eV. The developed microcalorimeter EDS system can measure a wide energy range, 1-20 keV, at one time with this high energy resolution that can resolve peaks from most of the elements. Although several further developments will be needed to enable practical use, highly accurate compositional analysis with high energy resolution will be realized by this microcalorimeter EDS system. PMID:19717388

  5. The Magnesium-Velocity Dispersion Relation and the Genesis of Early-Type Galaxies

    NASA Astrophysics Data System (ADS)

    Worthey, Guy; Collobert, Maela

    2003-03-01

    Available data on the magnesium-velocity dispersion (Mg-σ) relation for ~2000 early-type galaxies is analyzed. As noted previously, the Mg residuals from a fitted line are roughly Gaussian near the median but have an asymmetric blue tail, probably from subpopulations of relatively young stars. We define statistics for scatter and asymmetry of scatter in the Mg dimension and find impressive uniformity among data sets. We construct models of galaxy formation built to be as unbiased as possible toward the question of the importance of mergers in the formation of early-type galaxies. The observational constraints (Mg-σ width, asymmetry, and mean Mg strength, plus mean age and width of abundance distribution) are severe enough to eliminate almost all models. Eliminated are models with merger rates proportional to (1+z)n with n>0, models that assume early formation followed by recent drizzling of new stars, merger-only models in which the number of mergers exceeds ~80, merger-only models with less than ~20 mergers, and models with a cold dark matter power spectrum (at least within our approximations). The most successful models were those with merger probability constant or mildly declining with time, with the number of mergers needed to form the galaxy around 50 and gas fractions of ~0.2-0.35. These models are characterized by mean light-weighted ages of 8-9 Gyr (consistent with spectroscopic studies), an abundance distribution that does not exceed local constraints, and a look-back time behavior nearly indistinguishable from passive evolution of old stellar populations. Our simulations suggest that the evolution of median Mg index strength is not a good discriminator between mergers and passive evolution and that better discriminators such as Mg-σ scatter and asymmetry require N>1000 sample sizes with accuracies similar to today's local measurements.

  6. The Effect of Pollinator Type and Plant Spatial Structure on Patterns of Pollen-Mediated Gene Dispersal in Aquilegia Coerulea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background/Question/Methods - Direct estimation of pollen dispersal distances from paternity type analyses is often not possible. Therefore, recent emphasis have been on the development of indirect methods relying on the assumed decay with spatial distance in a measure of the genetic structure of p...

  7. A NMR-Based Carbon-Type Analysis of Diesel Fuel Blends From Various Sources

    SciTech Connect

    Bays, J. Timothy; King, David L.

    2013-05-10

    In collaboration with participants of the Coordinating Research Council (CRC) Advanced Vehicle/Fuels/Lubricants (AVFL) Committee, and project AVFL-19, the characteristics of fuels from advanced and renewable sources were compared to commercial diesel fuels. The main objective of this study was to highlight similarities and differences among the fuel types, i.e. ULSD, renewables, and alternative fuels, and among fuels within the different fuel types. This report summarizes the carbon-type analysis from 1H and 13C{1H} nuclear magnetic resonance spectroscopy (NMR) of 14 diesel fuel samples. The diesel fuel samples come from diverse sources and include four commercial ultra-low sulfur diesel fuels (ULSD), one gas-to-liquid diesel fuel (GTL), six renewable diesel fuels (RD), two shale oil-derived diesel fuels, and one oil sands-derived diesel fuel. Overall, the fuels examined fall into two groups. The two shale oil-derived samples and the oil-sand-derived sample closely resemble the four commercial ultra-low sulfur diesels, with SO1 and SO2 most closely matched with ULSD1, ULSD2, and ULSD4, and OS1 most closely matched with ULSD3. As might be expected, the renewable diesel fuels, with the exception of RD3, do not resemble the ULSD fuels because of their very low aromatic content, but more closely resemble the gas-to-liquid sample (GTL) in this respect. RD3 is significantly different from the other renewable diesel fuels in that the aromatic content more closely resembles the ULSD fuels. Fused-ring aromatics are readily observable in the ULSD, SO, and OS samples, as well as RD3, and are noticeably absent in the remaining RD and GTL fuels. Finally, ULSD3 differs from the other ULSD fuels by having a significantly lower aromatic carbon content and higher cycloparaffinic carbon content. In addition to providing important comparative compositional information regarding the various diesel fuels, this report also provides important information about the capabilities of NMR

  8. 27 CFR 19.685 - Change in type of alcohol fuel plant.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Change in type of alcohol fuel plant. 19.685 Section 19.685 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... Changes to Permit Information § 19.685 Change in type of alcohol fuel plant. (a) Small plants. If...

  9. Estimating Source Terms for Diverse Spent Nuclear Fuel Types

    SciTech Connect

    Brett Carlsen; Layne Pincock

    2004-11-01

    The U.S. Department of Energy (DOE) National Spent Nuclear Fuel Program is responsible for developing a defensible methodology for determining the radionuclide inventory for the DOE spent nuclear fuel (SNF) to be dispositioned at the proposed Monitored Geologic Repository at the Yucca Mountain Site. SNF owned by DOE includes diverse fuels from various experimental, research, and production reactors. These fuels currently reside at several DOE sites, universities, and foreign research reactor sites. Safe storage, transportation, and ultimate disposal of these fuels will require radiological source terms as inputs to safety analyses that support design and licensing of the necessary equipment and facilities. This paper summarizes the methodology developed for estimating radionuclide inventories associated with DOE-owned SNF. The results will support development of design and administrative controls to manage radiological risks and may later be used to demonstrate conformance with repository acceptance criteria.

  10. Interaction Layer Characteristics in U-xMo Dispersion/Monolithic Fuels

    SciTech Connect

    D. L. Porter

    2010-11-01

    Published data concerning the interaction layer (IL) formed between U-xMo fuel alloy and aluminum (Al)-based matrix or cladding materials was reviewed, including the effects of silicon (Si) content in the matrix/cladding, molybdenum (Mo) content in the fuel, pre irradiation thermal treatments, irradiation, and test temperature. The review revealed that tests conducted in the laboratory produce results different from those conducted in an irradiation environment. However, the laboratory testing relates well to thermal treatments performed prior to irradiation and helps in understanding the effects that these pre irradiation treatments have on in reactor performance. A pre-formed, Si-enriched IL seems to be important in delaying the onset of rapid growth of fission gas bubbles at low irradaiiation temperatures. Several other conclusions can be drawn: 1. An IL with phases akin to UAl3 is desired for optimum fuel performance, but at low temperatures, and especially in an irradiation atmosphere, the desired (Al+Si)/(U+Mo) ratio of three is difficult to produce. When the fuel operating temperature is low, it is important to create a pre-irradiation IL, enriched in Si. This pre-formed IL is relatively stable, performs well in terms of swelling resistance, and prevents rapid IL growth during irradiation. 2. At higher operating temperatures (>150–170°C), IL formation in reactor may not be so dependent on pre-irradiation IL formation, especially at high burnup; a pre-fabricated IL seems to be less stable at high burnup and high operating temperature. Moreover, the (Al+SI)/(U+Mo) ratio of three occurs more often at higher temperature. For these two reasons, it is important at high operating temperature to also have a matrix with significant Si content to create an IL in reactor with the right characteristics. 3. Out-of-reactor testing seems to indicate that Si in the matrix material is required in some concentration (2%, 5%, ?) to provide for a thin, Si-enriched IL formed

  11. Fast-Neutron Hodoscope at TREAT: Methods for Quantitative Determination of Fuel Dispersal

    SciTech Connect

    De Volci, A.; Fink, C. L.; Marsh, G. E.; Rhodes, E. A.; Stanford, G. S.

    1980-01-01

    Fuel-motion surveillance using the fast-neutron hodoscope in TREAT experiments has advanced from an initial role of providing time/location/velocity data to that of offering quantitative mass results. The material and radiation surroundings of tha test section contribute to intrinsic and instrumental effects upon hodoscope detectors that require detailed corrections. Depending upon the experiment, count rate compensation is usually required for deadtime, power level, nonlinear response, efficiency, background, and detector calibration. Depending on their magnitude and amenability to analytical and empirical treatment, systematic corrections may be needed for self-shielding, self-multiplication, self-attenuation, flux depression, and other effects. Current verified hodoscope response (for 1- to 7-pin fuel bundles) may be paramatrically characterized under optimum conditions by 1-ms time resolution; 0.25-mm lateral and 5-mm axial-motion displacement resolution; and 50-mg single-pin mass resolution. The experimental and theoretical foundation for this performance is given, with particular emphasis on the geometrical response function and the statistical limits of fuel-motion resolution. Comparisons are made with alternative diagnostic systems.

  12. Nuclear waste treatment - Studying the mixed ion type effects and concentration on the behaviour of oxide dispersions

    SciTech Connect

    Omokanye, Qanitalillahi; Biggs, Simon

    2007-07-01

    In order to gain good control over a particulate dispersion it is necessary to accurately characterise the strength of inter-particle forces that may be operating. Such control is not routinely used, as yet, in the nuclear industry despite the possible benefits. We are investigating the impact of mixed electrolyte systems, for example NaCl and Na{sub 2}SO{sub 4}, on the stability of oxide simulant particle dispersions. The electro-acoustic zeta potentials and shear yield stresses for concentrated dispersions have been measured across a range of pH conditions and electrolyte concentrations (0.001 M - 1.0 M). This paper summarizes initial data from these studies showing how the shear yield stress of concentrated aqueous oxide particle dispersions, can be adjusted through regulation of pH and the addition of background electrolytes (salt). The yield stress as a function of pH for these dispersions in mixed electrolytes showed a direct correlation with corresponding measurements of the zeta potential. Changes in the background electrolyte concentration or type were seen to cause a shift in the position of the isoelectric point (iep). Measurements of the shear yield stress showed a maximum at the iep corresponding to the position of maximum instability in the suspension. The consequences of these data for the efficient treatment of solid-liquid systems will be discussed. (authors)

  13. Wind tunnel investigation of the effect of platform-type structures on dispersion of effluents from short stacks

    SciTech Connect

    Petersen, R.L.

    1986-12-01

    This paper is directed to those persons interested in predicting concentrations downwind of platform-type structures associated with oil or gas facilities that operate on the Outer Continental Shelf. The specific purpose of this study was to determine the effect of platform-type structures on the dispersion of pollutant plumes and to assess the adequacy of the building wake algorithm included in the Offshore and Coastal Dispersion (OCD) Model. To meet the study objectives, a comprehensive wind-tunnel modeling study was conducted. Scale models of three typical oil platforms were positioned in an open-circuit wind tunnel and various source and meteorological conditions were simulated. Concentration and visual measurements were then obtained so that the dispersion characteristics could be quantitatively and qualitatively defined. Prior to conducting the platform wake evaluation, wind tunnel tests were conducted simulating two cases from tracer field experiments conducted in the Gulf of Mexico. The simulations demonstrated that the wind tunnel can adequately simulate dispersion over water.

  14. Development of a Fast Breeder Reactor Fuel Bundle Deformation Analysis Code - BAMBOO: Development of a Pin Dispersion Model and Verification by the Out-of-Pile Compression Test

    SciTech Connect

    Uwaba, Tomoyuki; Ito, Masahiro; Ukai, Shigeharu

    2004-02-15

    To analyze the wire-wrapped fast breeder reactor fuel pin bundle deformation under bundle/duct interaction conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. This code uses the three-dimensional beam element to calculate fuel pin bowing and cladding oval distortion as the primary deformation mechanisms in a fuel pin bundle. The pin dispersion, which is disarrangement of pins in a bundle and would occur during irradiation, was modeled in this code to evaluate its effect on bundle deformation. By applying the contact analysis method commonly used in the finite element method, this model considers the contact conditions at various axial positions as well as the nodal points and can analyze the irregular arrangement of fuel pins with the deviation of the wire configuration.The dispersion model was introduced in the BAMBOO code and verified by using the results of the out-of-pile compression test of the bundle, where the dispersion was caused by the deviation of the wire position. And the effect of the dispersion on the bundle deformation was evaluated based on the analysis results of the code.

  15. An indoor three-mirror phasing experiment system based on a dispersed Hartmann type sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Cui, Xiangqun; Liu, Genrong; Wang, Yuefei; Li, Yeping; Zhang, Yajun; Zhang, Liang; Zeng, Yizhong

    2010-07-01

    Telescope with much larger primary can collect much more light and it is always pursued by the astronomers. Instead of using a monolithic primary, more and more large telescopes, which are now planed or in construction, invariably adopted segmented primary mirror. Therefore, how to sense and phase the primary mirror is the key technology. Unlike edge sensors, which need careful calibrations, dispersed Hartmann sensor (DHS) is non-contact method using broadband point light sources, and it can estimate piston by the two-direction spectrum formed by the transmissive grating's dispersion and lenslet array. Thus it can realize the combination of co-focusing and co-phasing. In this paper, we introduce the design of our dispersed Hartmann sensor together with its principle. We also manufacture a DHS sensor and do real tests on our existing segmented mirror optics platform. Finally some conclusions are given based on the test results.

  16. Dispersive ground plane core-shell type optical monopole antennas fabricated with electron beam induced deposition.

    PubMed

    Acar, Hakkı; Coenen, Toon; Polman, Albert; Kuipers, Laurens Kobus

    2012-09-25

    We present the bottom-up fabrication of dispersive silica core, gold cladding ground plane optical nanoantennas. The structures are made by a combination of electron-beam induced deposition of silica and sputtering of gold. The antenna lengths range from 300 to 2100 nm with size aspect ratios as large as 20. The angular emission patterns of the nanoantennas are measured with angle-resolved cathodoluminescence spectroscopy and compared with finite-element methods. Good overall correspondence between the the measured and calculated trends is observed. The dispersive nature of these plasmonic monopole antennas makes their radiation profile highly tunable. PMID:22889269

  17. Near-field dispersal modeling for liquid fuel-air explosives

    SciTech Connect

    Gardner, D.R.

    1990-07-01

    The near-field, explosive dispersal of a liquid into air has been explored using a combination of analytical and numerical models. The near-field flow regime is transient, existing only as long as the explosive forces produced by the detonation of the burster charge dominate or are approximately equal in magnitude to the aerodynamic drag forces on the liquid. The near-field model provides reasonable initial conditions for the far-field model, which is described in a separate report. The near-field model consists of the CTH hydrodynamics code and a film instability model. In particular, the CTH hydrodynamics code is used to provide initial temperature, pressure, and velocity fields, and bulk material distribution for the far-field model. The film instability model is a linear stability model for a radially expanding fluid film, and is used to provide a lower bound on the breakup time and an upper and lower bound on the initial average drop diameter for the liquid following breakup. Predictions of the liquid breakup time and the initial arithmetic average drop diameter from the model compare favorably with the sparse experimental data. 26 refs., 20 figs., 8 tabs.

  18. MECHANICALLY-JOINED PLATE-TYPE ALUMINUM-CLAD FUEL ELEMENT

    DOEpatents

    Erwin, J.H.

    1962-12-11

    A method of fabricating MTR-type fuel elements is described wherein dove- tailed joints are used to fasten fuel plates to supporting side members. The method comprises the steps of dove-tailing the lateral edges of the fuel plates, inserting the dove-tailed edges into corresponding recesses which are provided in a pair of supporting side members, and compressing the supporting side members in a direction so as to close the recesses onto the dove-tailed edges. (AEC)

  19. Research on the Influence of the Type of Surfactant and Concentrator in Aqueous Dispersion of Pigments.

    PubMed

    Makarewicz, Edwin; Michalik, Agnieszka

    2014-01-01

    This work reports tests performed to evaluate the stability of aqueous dispersions of inorganic oxide pigments with different specific surface areas, with the use of anionic and non-ionic surfactants and concentrators. Color mixtures of oxide compounds of blue, green, olive and brown with the unit cell spinel structure were used as pigments. The sodium salt of sulfosuccinic acid monoester, oxyethylenated nonylphenol and ethoxylated derivatives of lauryl alcohol, fatty alcohol and fatty amine were used as surfactants. The concentrators used were: poly(vinyl alcohol), the sodium salt of carboxymethyl cellulose as well as a water-based polyurethane oligomer. The highest dispersion efficiency was found for dispersed systems in which surfactant and concentrator were incorporated in the formula. The one containing the sodium salt of carboxymethyl cellulose or polyurethane oligomer with ethoxylated saturated fatty alcohol or fatty amine was found to be the most efficient. It was discovered that a higher dispersion efficiency corresponds to pigments with larger specific surface. The efficiency is also found to improve when the concentrator is an acrylic polymer or copolymer made up of two acrylic species. In this case, the concentrator interaction with the surfactant is more effective if the value of its boundary viscosity number is higher. This observation confirms the existence of interactions between macro-chains of the concentrator and surfactant molecules forming micelles with the pigment particles. PMID:24955004

  20. UO 2 fuel behavior under RIA type tests

    NASA Astrophysics Data System (ADS)

    Negut, Gheorghe; Popov, Mircea

    1992-06-01

    This paper describes the test conducted to investigate the failure threshold of the fuel when subjected to RIA, accomplished in the TRIGA ACPR Nuclear Research Institute, Pitesti. The reactor facility, the capsule used in experiments and the experimental results are presented. The failure threshold was determined at 200 cal/g for an atmospheric gap pressure comparable with similar tests.

  1. 14 CFR 26.35 - Changes to type certificates affecting fuel tank flammability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Changes to type certificates affecting fuel tank flammability. 26.35 Section 26.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CONTINUED AIRWORTHINESS AND SAFETY IMPROVEMENTS FOR TRANSPORT CATEGORY AIRPLANES Fuel Tank Flammability §...

  2. 14 CFR 26.33 - Holders of type certificates: Fuel tank flammability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... installation of fuel tank IMM that comply with 14 CFR 25.981(c) in effect on December 26, 2008. (e... in the Airworthiness Limitations Section (ALS) of the ICA required by 14 CFR 25.1529 or paragraph (f... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Holders of type certificates: Fuel...

  3. Development of a 200kW multi-fuel type PAFC power plant

    SciTech Connect

    Take, Tetsuo; Kuwata, Yutaka; Adachi, Masahito; Ogata, Tsutomu

    1996-12-31

    Nippon Telegraph and Telephone Corporation (NFT) has been developing a 200 kW multi-fuel type PAFC power plant which can generate AC 200 kW of constant power by switching fuel from pipeline town gas to liquefied propane gas (LPG) and vice versa. This paper describes the outline of the demonstration test plant and test results of its fundamental characteristics.

  4. 27 CFR 19.685 - Change in type of alcohol fuel plant.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Change in type of alcohol fuel plant. 19.685 Section 19.685 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel...

  5. 27 CFR 19.921 - Change in type of alcohol fuel plant.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Changes Affecting Applications and Permits § 19.921 Change in type of alcohol fuel plant. (a) Small plants. If the proprietor of a small plant wishes to increase production (including receipts) to a level in... fuel plant. 19.921 Section 19.921 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX...

  6. Microstructural characterization of a thin film ZrN diffusion barrier in an As-fabricated U–7Mo/Al matrix dispersion fuel plate

    SciTech Connect

    Keiser, Dennis D.; Perez, Emmanuel; Wiencek, Tom; Leenaers, Ann; Van den Berghe, Sven

    2015-03-01

    The United States High Performance Research Reactor Fuel Development program is developing low enriched uranium fuels for application in research and test reactors. One concept utilizes U–7 wt.% Mo (U–7Mo) fuel particles dispersed in Al matrix, where the fuel particles are coated with a 1 μm-thick ZrN coating. The ZrN serves as a diffusion barrier to eliminate a deleterious reaction that can occur between U–7Mo and Al when a dispersion fuel is irradiated under aggressive reactor conditions. To investigate the final microstructure of a physically-vapor-deposited ZrN coating in a dispersion fuel plate after it was fabricated using a rolling process, characterization samples were taken from a fuel plate that was fabricated at 500 °C using ZrN-coated U–7Mo particles, Al matrix and AA6061 cladding. Scanning electron and transmission electron microscopy analysis were performed. Data from these analyses will be used to support future microstructural examinations of irradiated fuel plates, in terms of understanding the effects of irradiation on the ZrN microstructure, and to determine the role of diffusion barrier microstructure in eliminating fuel/matrix interactions during irradiation. The as-fabricated coating was determined to be cubic-ZrN (cF8) phase. It exhibited a columnar microstructure comprised of nanometer-sized grains and a region of relatively high porosity, mainly near the Al matrix. Small impurity-containing phases were observed at the U–7Mo/ZrN interface, and no interaction zone was observed at the ZrN/Al interface. The bonding between the U–7Mo and ZrN appeared to be mechanical in nature. A relatively high level of oxygen was observed in the ZrN coating, extending from the Al matrix in the ZrN coating in decreasing concentration. The above microstructural characteristics are discussed in terms of what may be most optimal for a diffusion barrier in a dispersion fuel plate application.

  7. Microstructural characterization of a thin film ZrN diffusion barrier in an As-fabricated U-7Mo/Al matrix dispersion fuel plate

    NASA Astrophysics Data System (ADS)

    Keiser, Dennis D.; Perez, Emmanuel; Wiencek, Tom; Leenaers, Ann; Van den Berghe, Sven

    2015-03-01

    The United States High Performance Research Reactor Fuel Development program is developing low enriched uranium fuels for application in research and test reactors. One concept utilizes U-7 wt.% Mo (U-7Mo) fuel particles dispersed in Al matrix, where the fuel particles are coated with a 1 μm-thick ZrN coating. The ZrN serves as a diffusion barrier to eliminate a deleterious reaction that can occur between U-7Mo and Al when a dispersion fuel is irradiated under aggressive reactor conditions. To investigate the final microstructure of a physically-vapor-deposited ZrN coating in a dispersion fuel plate after it was fabricated using a rolling process, characterization samples were taken from a fuel plate that was fabricated at 500 °C using ZrN-coated U-7Mo particles, Al matrix and AA6061 cladding. Scanning electron and transmission electron microscopy analysis were performed. Data from these analyses will be used to support future microstructural examinations of irradiated fuel plates, in terms of understanding the effects of irradiation on the ZrN microstructure, and to determine the role of diffusion barrier microstructure in eliminating fuel/matrix interactions during irradiation. The as-fabricated coating was determined to be cubic-ZrN (cF8) phase. It exhibited a columnar microstructure comprised of nanometer-sized grains and a region of relatively high porosity, mainly near the Al matrix. Small impurity-containing phases were observed at the U-7Mo/ZrN interface, and no interaction zone was observed at the ZrN/Al interface. The bonding between the U-7Mo and ZrN appeared to be mechanical in nature. A relatively high level of oxygen was observed in the ZrN coating, extending from the Al matrix in the ZrN coating in decreasing concentration. The above microstructural characteristics are discussed in terms of what may be most optimal for a diffusion barrier in a dispersion fuel plate application.

  8. Development of an experiment for determining the autoignition characteristics of aircraft-type fuels

    NASA Technical Reports Server (NTRS)

    Spadaccini, L. J.

    1977-01-01

    An experimental test apparatus was developed to determine the autoignition characteristics of aircraft-type fuels in premixing prevaporizing passages at elevated temperatures and pressures. The experiment was designed to permit independent variation and evaluation of the experimental variables of pressure, temperature, flow rate, and fuel-air ratio. A comprehensive review of the autoignition literature is presented. Performance verification tests consisting of measurements of the ignition delay times for several lean fuel-air mixture ratios were conducted using Jet-A fuel at inlet air temperatures in the range 600 K to 900 K and pressures in the range 9 atm to 30 atm.

  9. Not my "type": larval dispersal dimorphisms and bet-hedging in opisthobranch life histories.

    PubMed

    Krug, Patrick J

    2009-06-01

    When conditions fluctuate unpredictably, selection may favor bet-hedging strategies that vary offspring characteristics to avoid reproductive wipe-outs in bad seasons. For many marine gastropods, the dispersal potential of offspring reflects both maternal effects (egg size, egg mass properties) and larval traits (development rate, habitat choice). I present data for eight sea slugs in the genus Elysia (Opisthobranchia: Sacoglossa), highlighting potentially adaptive variation in traits like offspring size, timing of metamorphosis, hatching behavior, and settlement response. Elysia zuleicae produced both planktotrophic and lecithotrophic larvae, a true case of poecilogony. Both intracapsular and post-hatching metamorphosis occurred among clutches of "Boselia" marcusi, E. cornigera, and E. crispata, a dispersal dimorphism often misinterpreted as poecilogony. Egg masses of E. tuca hatched for up to 16 days but larvae settled only on the adult host alga Halimeda, whereas most larvae of E. papillosa spontaneously metamorphosed 5-7 days after hatching. Investment in extra-capsular yolk may allow mothers to increase larval size relative to egg size and vary offspring size within and among clutches. Flexible strategies of larval dispersal and offspring provisioning in Elysia spp. may represent adaptations to the patchy habitat of these specialized herbivores, highlighting the evolutionary importance of variation in a range of life-history traits. PMID:19556600

  10. Comparing evapotranspiration partitioning after different types of rain events using stable isotopes and lagrangian dispersion analysis

    NASA Astrophysics Data System (ADS)

    Hogan, Patrick; Parajka, Juraj

    2016-04-01

    The eddy covariance method has become one of the standard methods for measuring evapotranspiration (ET) at the field scale, however it cannot separate transpiration from evaporation and it is also limited within plant canopies due to distortion of the turbulent wind fields. Possible solutions to these limitations include combining EC measurements made above the canopy coupled with either source/sink distribution models or stable isotope ET partitioning models. During the summer of 2014 the concentration and isotopic ratio of water vapour within the canopy of a growing maize field at the Hydrological Open Air Laboratory (HOAL) catchment was measured using a Picarro field sampling device. A tripod mounted eddy covariance device was used to calculate the ET value for the field. The first objective of this experiment is to compare the ET partitioning results made using the stable isotope Keeling Plot method within a canopy to two different lagrangian dispersion analysis methods, the Localised Near Field theory of Raupach (1989a) and the Warland and Thurtell (2000) dispersion model. Preliminary results show good agreement during dry conditions with the dispersion methods overestimating the fraction of transpiration directly after a rain event. The second objective is then to analyse and compare the soil evaporation response for two different kinds of rain events using the stable isotope results.

  11. Types of Pollen Dispersal Units in Orchids, and their Consequences for Germination and Fertilization

    PubMed Central

    Pacini, Ettore; Hesse, Michael

    2002-01-01

    The various pollen dispersal units (PDU) found in orchids are discussed together with possible evolutionary trends and the consequences for germination and fertilization. Orchids with monad and tetrad pollen form more complex dispersal units by means of pollenkitt, elastoviscin, a callosic wall, common walls or a combination of these. Evolutionary trends include (1) from pollenkitt to elastoviscin; (2) from monad to tetrads and multiples of tetrads; (3) from partially dehydrated (<30 %) to partially hydrated (>30 %) pollen; and (4) from monad pollen to PDUs with many pollen grains. The biological consequences concern both male and female reproductive systems. Some features of the male side are present in all orchids irrespective of the pollen dispersal unit, whereas other characters are found only in orchids with pollinia; the same applies for the female counterpart. Pollen grains of orchids with pollinia germinate at least 24 h after pollination because the pollen grains/tetrads must swell and make space for the growth of pollen tubes. PMID:12102520

  12. Control system of a dispersed fringe type sensing system of active optics

    NASA Astrophysics Data System (ADS)

    Zhang, Yajun; Zhang, Zhenchao; Zhang, Yong

    2010-07-01

    Active optics plays an important part in segmented mirrors of astronomy telescopes. A dispersed fringe sensor(DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. DFS can estimate the piston between segments only through the spectrum formed by the transmissive grating's dispersion and therefore can replace the edge sensors. So we build an system in our lab to experiment the DFS method. The whole control system of DFS is put forward, including control of displacement actuators and control of shifting the optical fiber. Control of displacement actuators consists in industry computer, HY-6120 I/O card, six stepper motor and other parts. Some theoretical analysis and experiment tests reveal that the actuator could be controlled to 5nm and without backlash by this control strategy. The optical fiber could be shifted out of optical path or shifted in part or whole of optical path so that the spectrum formed by the transmissive grating's dispersion could alter. When six actuators are moving, the piston is changing, and the spectrum is also moving and altering. And the whole control of DFS system is constructed now and seems well. Further test and experiment will be carry out.

  13. Atmospheric Dispersion Modeling of 137Cs generated from Nuclear Spent Fuel under Hypothetic Accidental Condition in the BNPP Area

    NASA Astrophysics Data System (ADS)

    Lee, Jongkuk; Lee, Kwan-Hee; Yook, Daesik; Kim, Sung Il; Lee, Byung Soo

    2016-04-01

    This study presents the results of atmosphere dispersion modeling using CALPUFF code that are based on computational simulation to evaluate the environmental characteristics of the Barakah nuclear power plant (BNPP) in west area of UAE. According to meteorological data analysis (2012~2013), the winds from the north(7.68%) and west(9.05%) including NNW(41.63%), NW(28.55%), and WNW(6.31%) winds accounted for more than 90% of the wind directions. East(0.2%) and south(0.6%) direction wind, including ESE(0.31%), SE(0.38%), and SSE(0.38%) were rarely distributed during the simulation period. Seasonal effects were not showed. However, a discrepancy in the tendency between daytime and night-time was observed. Approximately 87% of the wind speed was distributed below 5.4m/s (17%, 47% and 23% between the speeds of 0.5-1.8m/s 1.8-3.3m/s and 3.3-5.4m/s, respectively) during the annual period. Seasonal wind speed distribution results presented very similar pattern of annual distribution. Wind speed distribution of day and night, on the other hand, had a discrepancy with annual modeling results than seasonal distribution in some sections. The results for high wind speed (more than 10.8m/s) showed that this wind blew from the west. This high wind speed is known locally as the 'Shamal', which occurs rarely, lasting one or two days with the strongest winds experienced in association with gust fronts and thunderstorms. Six variations of cesium-137 (137Cs) dispersion test were simulated under hypothetic severe accidental condition. The 137Cs dispersion was strongly influenced by the direction and speed of the main wind. From the test cases, east-south area of the BNPP site was mainly influenced by 137Cs dispersion. A virtual receptor was set and calculated for observation of the 137Cs movement and accumulation. Surface roughness tests were performed for the analysis of topographic conditions. According to the surface condition, there are various surface roughness length. Four types

  14. Fuel type characterization and potential fire behavior estimation in Sardinia and Corsica islands

    NASA Astrophysics Data System (ADS)

    Bacciu, V.; Pellizzaro, G.; Santoni, P.; Arca, B.; Ventura, A.; Salis, M.; Barboni, T.; Leroy, V.; Cancellieri, D.; Leoni, E.; Ferrat, L.; Perez, Y.; Duce, P.; Spano, D.

    2012-04-01

    Wildland fires represent a serious threat to forests and wooded areas of the Mediterranean Basin. As recorded by the European Commission (2009), during the last decade Southern Countries have experienced an annual average of about 50,000 forest fires and about 470,000 burned hectares. The factor that can be directly manipulated in order to minimize fire intensity and reduce other fire impacts, such as three mortality, smoke emission, and soil erosion, is wildland fuel. Fuel characteristics, such as vegetation cover, type, humidity status, and biomass and necromass loading are critical variables in affecting wildland fire occurrence, contributing to the spread, intensity, and severity of fires. Therefore, the availability of accurate fuel data at different spatial and temporal scales is needed for fire management applications, including fire behavior and danger prediction, fire fighting, fire effects simulation, and ecosystem simulation modeling. In this context, the main aims of our work are to describe the vegetation parameters involved in combustion processes and develop fire behavior fuel maps. The overall work plan is based firstly on the identification and description of the different fuel types mainly affected by fire occurrence in Sardinia (Italy) and Corsica (France) Islands, and secondly on the clusterization of the selected fuel types in relation to their potential fire behavior. In the first part of the work, the available time series of fire event perimeters and the land use map data were analyzed with the purpose of identifying the main land use types affected by fires. Thus, field sampling sites were randomly identified on the selected vegetation types and several fuel variables were collected (live and dead fuel load partitioned following Deeming et al., (1977), depth of fuel layer, plant cover, surface area-to-volume ratio, heat content). In the second part of the work, the potential fire behavior for every experimental site was simulated using

  15. NACA Investigation of Fuel Performance in Piston-Type Engines

    NASA Technical Reports Server (NTRS)

    Barnett, Henry C

    1951-01-01

    This report is a compilation of many of the pertinent research data acquired by the National Advisory Committee for Aeronautics on fuel performance in piston engines. The original data for this compilation are contained in many separate NACA reports which have in the present report been assembled in logical chapters that summarize the main conclusions of the various investigations. Complete details of each investigation are not included in this summary; however, such details may be found, in the original reports cited at the end of each chapter.

  16. Effect of fuel injector type on performance and emissions of reverse-flow combustor

    NASA Technical Reports Server (NTRS)

    Norgren, C. T.; Riddlebaugh, S. M.

    1981-01-01

    The combustion process in a reverse-flow combustor suitable for a small gas turbine engine was investigated to evaluate the effect of fuel injector type on performance and emissions. Fuel injector configurations using pressure-atomizing, spill-flow, air blast, and air-assist techniques were compared and evaluated on the basis of performance obtained in a full-scale experimental combustor operated at inlet conditions corresponding to takeoff, cruise, low power, and idle and typical of a 16:1-pressure-ratio turbine engine. Major differences in combustor performance and emissions characteristics were experienced with each injector type even though the aerodynamic configuration was common to most combustor models. Performance characteristics obtained with the various fuel injector types could not have been predicted from bench-test injector spray characteristics. The effect of the number of operating fuel injectors on performance and emissions is also presented.

  17. Infrared spectroscopy for the determination of hydrocarbon types in jet fuels

    NASA Technical Reports Server (NTRS)

    Buchar, C. S.

    1981-01-01

    The concentration of hydrocarbon types in conventional jet fuels and synfuels can be measured using a computerized infrared spectrophotometer. The computerized spectrophotometer is calibrated using a fuel of known aromatic and olefinic content. Once calibration is completed, other fuels can be rapidly analyzed using an analytical program built into the computer. The concentration of saturates can be calculated as 100 percent minus the sum of the aromatic and olefinic concentrations. The analysis of a number of jet fuels produced an average standard deviation of 1.76 percent for aromatic types and one of 3.99 percent for olefinic types. Other substances such as oils and organic mixtures can be analyzed for their hydrocarbon content.

  18. Microstructural Characterization of a Mg Matrix U-Mo Dispersion Fuel Plate Irradiated in the Advanced Test Reactor to High Fission Density: SEM Results

    NASA Astrophysics Data System (ADS)

    Keiser, Dennis D.; Jue, Jan-Fong; Miller, Brandon D.; Gan, Jian; Robinson, Adam B.; Medvedev, Pavel G.; Madden, James W.; Moore, Glenn A.

    2016-04-01

    Low-enriched (U-235 <20 pct) U-Mo dispersion fuel is being developed for use in research and test reactors. In most cases, fuel plates with Al or Al-Si alloy matrices have been tested in the Advanced Test Reactor to support this development. In addition, fuel plates with Mg as the matrix have also been tested. The benefit of using Mg as the matrix is that it potentially will not chemically interact with the U-Mo fuel particles during fabrication or irradiation, whereas with Al and Al-Si alloys such interactions will occur. Fuel plate R9R010 is a Mg matrix fuel plate that was aggressively irradiated in ATR. This fuel plate was irradiated as part of the RERTR-8 experiment at high temperature, high fission rate, and high power, up to high fission density. This paper describes the results of the scanning electron microscopy (SEM) analysis of an irradiated fuel plate using polished samples and those produced with a focused ion beam. A follow-up paper will discuss the results of transmission electron microscopy (TEM) analysis. Using SEM, it was observed that even at very aggressive irradiation conditions, negligible chemical interaction occurred between the irradiated U-7Mo fuel particles and Mg matrix; no interconnection of fission gas bubbles from fuel particle to fuel particle was observed; the interconnected fission gas bubbles that were observed in the irradiated U-7Mo particles resulted in some transport of solid fission products to the U-7Mo/Mg interface; the presence of microstructural pathways in some U-9.1 Mo particles that could allow for transport of fission gases did not result in the apparent presence of large porosity at the U-7Mo/Mg interface; and, the Mg-Al interaction layers that were present at the Mg matrix/Al 6061 cladding interface exhibited good radiation stability, i.e. no large pores.

  19. Microstructural Characterization of a Mg Matrix U-Mo Dispersion Fuel Plate Irradiated in the Advanced Test Reactor to High Fission Density: SEM Results

    NASA Astrophysics Data System (ADS)

    Keiser, Dennis D.; Jue, Jan-Fong; Miller, Brandon D.; Gan, Jian; Robinson, Adam B.; Medvedev, Pavel G.; Madden, James W.; Moore, Glenn A.

    2016-06-01

    Low-enriched (U-235 <20 pct) U-Mo dispersion fuel is being developed for use in research and test reactors. In most cases, fuel plates with Al or Al-Si alloy matrices have been tested in the Advanced Test Reactor to support this development. In addition, fuel plates with Mg as the matrix have also been tested. The benefit of using Mg as the matrix is that it potentially will not chemically interact with the U-Mo fuel particles during fabrication or irradiation, whereas with Al and Al-Si alloys such interactions will occur. Fuel plate R9R010 is a Mg matrix fuel plate that was aggressively irradiated in ATR. This fuel plate was irradiated as part of the RERTR-8 experiment at high temperature, high fission rate, and high power, up to high fission density. This paper describes the results of the scanning electron microscopy (SEM) analysis of an irradiated fuel plate using polished samples and those produced with a focused ion beam. A follow-up paper will discuss the results of transmission electron microscopy (TEM) analysis. Using SEM, it was observed that even at very aggressive irradiation conditions, negligible chemical interaction occurred between the irradiated U-7Mo fuel particles and Mg matrix; no interconnection of fission gas bubbles from fuel particle to fuel particle was observed; the interconnected fission gas bubbles that were observed in the irradiated U-7Mo particles resulted in some transport of solid fission products to the U-7Mo/Mg interface; the presence of microstructural pathways in some U-9.1 Mo particles that could allow for transport of fission gases did not result in the apparent presence of large porosity at the U-7Mo/Mg interface; and, the Mg-Al interaction layers that were present at the Mg matrix/Al 6061 cladding interface exhibited good radiation stability, i.e. no large pores.

  20. 40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-cycle fuel economy values for a model type. 600.209-08 Section 600.209-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF... Calculating Fuel Economy Values § 600.209-08 Calculation of vehicle-specific 5-cycle fuel economy values for...

  1. Simulations of pollutant dispersion within idealised urban-type geometries with CFD and integral models

    NASA Astrophysics Data System (ADS)

    Di Sabatino, Silvana; Buccolieri, Riccardo; Pulvirenti, Beatrice; Britter, Rex

    Until recently, urban air quality modelling has been based on operational models of an integral nature. The use of computational fluid dynamics (CFD) models to address the same problems is increasing rapidly. Operational models e.g. OSPM, AERMOD, ADMS-Urban have undergone many comprehensive formal evaluations as to their "fitness for purpose" while CFD models do not have such an evaluation record in the urban air quality context. This paper looks at the application of both approaches to common problems. In particular, pollutant dispersion from point and line sources in the simplest neutral atmospheric boundary layer and line sources placed within different regular building geometries is studied with the CFD code FLUENT and the atmospheric dispersion model ADMS-Urban. Both the effect of street canyons of different aspect ratios and various obstacle array configurations consisting of cubical buildings are investigated. The standard k-ɛ turbulence model and the advection-diffusion (AD) method (in contrast to the Lagrangian particle tracking method) are used for the CFD simulations. Results from the two approaches are compared. Overall CFD simulations with the appropriate choice of coefficients produce similar concentration fields to those predicted by the integral approach. However, some quantitative differences are observed. These differences can be explained by investigating the role of the Schmidt number in the CFD simulations. A further interpretation of the differences between the two approaches is given by quantifying the exchange velocities linked to the mass fluxes between the in-canopy and above-canopy layers.

  2. Influence of nano-sized LSCF cathode and its firing temperature on electrochemical performance in oxygen-excess-type solid electrolyte (OESE)-based fuel cells

    NASA Astrophysics Data System (ADS)

    Mieda, Hiroyuki; Mineshige, Atsushi; Saito, Atsushi; Yazawa, Tetsuo; Yoshioka, Hideki; Mori, Ryohei

    2014-12-01

    Dense films of an oxygen-excess-type solid electrolyte (OESE) based on Mg-doped lanthanum silicate (MDLS) were fabricated and applied to electrolyte materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). To obtain dense MDLS films on NiO-MDLS porous substrates, a conventional spin-coating technique using the MDLS printable paste, obtained by mixing nano-sized MDLS particles and a dispersant, was employed. The Ni-MDLS anode supported single cells were then fabricated by printing porous cathode layer onto the electrolyte film surface. By optimizing fabrication conditions of an MDLS film and cathode, the highly active cathode/OESE interface (ASR = 0.23 Ω cm2 at 873 K) were successfully obtained, which resulted in high power density of 0.166 W cm-2 at 873 K in the fuel cell test when operated with argon-diluted hydrogen and pure oxygen as the fuel and the cathode gas, respectively.

  3. Comparative analysis of the atomization characteristics of fifteen biodiesel fuel types

    SciTech Connect

    Allen, C.A.W.; Watts, K.C.

    2000-04-01

    Engine results using biofuels have varied considerably in the reported literature. This article addresses two potential sources of this variation, atomization differences and impurities due to lack of quality control during production. Atomization is the first process encountered during the combustion of fuels in a compression ignition engine and is largely determined by the fuel's viscosity and surface tension. Previous work using five experimentally produced methyl ester biodiesel fuels showed that the viscosity and surface tension could be predicted from their fatty acid ester composition, and the atomization characteristics in turn could be predicted from their viscosity and surface tension. This article utilizes the results of that work to give a quantitative comparison of the atomization characteristics of fifteen biodiesel fuel types using the fuel's viscosity and surface tension, predicted directly from the fatty acid composition of the fuels. Except for coconut and rapeseed biodiesel fuels, all of the rest of the 15 biodiesel fuels had similar atomization characteristics. Since the most likely contaminant in the fuel from the processing was residual glycerides, their effect on viscosity and surface tension was studied experimentally and their effect on the atomization characteristics was computed.

  4. Fuel cell separator plate with bellows-type sealing flanges

    DOEpatents

    Louis, G.A.

    1984-05-29

    A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which steps just short of the plate, these side walls affording resilient compressibility to the sealing flange in a direction generally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

  5. Fuel cell separator plate with bellows-type sealing flanges

    DOEpatents

    Louis, George A.

    1986-08-05

    A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which stops just short of the plate, these side walls affording resilient compressibility to the sealing flange in a directiongenerally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

  6. Charring temperatures are driven by the fuel types burned in a peatland wildfire

    PubMed Central

    Hudspith, Victoria A.; Belcher, Claire M.; Yearsley, Jonathan M.

    2014-01-01

    Peatlands represent a globally important carbon store; however, the human exploitation of this ecosystem is increasing both the frequency and severity of fires on drained peatlands. Yet, the interactions between the hydrological conditions (ecotopes), the fuel types being burned, the burn severity, and the charring temperatures (pyrolysis intensity) remain poorly understood. Here we present a post-burn assessment of a fire on a lowland raised bog in Co. Offaly, Ireland (All Saints Bog). Three burn severities were identified in the field (light, moderate, and deeply burned), and surface charcoals were taken from 17 sites across all burn severities. Charcoals were classified into two fuel type categories (either ground or aboveground fuel) and the reflectance of each charcoal particle was measured under oil using reflectance microscopy. Charcoal reflectance shows a positive relationship with charring temperature and as such can be used as a temperature proxy to reconstruct minimum charring temperatures after a fire event. Resulting median reflectance values for ground fuels are 1.09 ± 0.32%Romedian, corresponding to estimated minimum charring temperatures of 447°C ± 49°C. In contrast, the median charring temperatures of aboveground fuels were found to be considerably higher, 646°C ± 73°C (3.58 ± 0.77%Romedian). A mixed-effects modeling approach was used to demonstrate that the interaction effects of burn severity, as well as ecotope classes, on the charcoal reflectance is small compared to the main effect of fuel type. Our findings reveal that the different fuel types on raised bogs are capable of charring at different temperatures within the same fire, and that the pyrolysis intensity of the fire on All Saints Bog was primarily driven by the fuel types burning, with only a weak association to the burn severity or ecotope classes. PMID:25566288

  7. 41 CFR 102-34.325 - What type of fuel do I use in Government motor vehicles?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false What type of fuel do I use in Government motor vehicles? 102-34.325 Section 102-34.325 Public Contracts and Property... PROPERTY 34-MOTOR VEHICLE MANAGEMENT Motor Vehicle Fueling § 102-34.325 What type of fuel do I use...

  8. 41 CFR 102-34.325 - What type of fuel do I use in Government motor vehicles?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false What type of fuel do I use in Government motor vehicles? 102-34.325 Section 102-34.325 Public Contracts and Property... PROPERTY 34-MOTOR VEHICLE MANAGEMENT Motor Vehicle Fueling § 102-34.325 What type of fuel do I use...

  9. 40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-cycle fuel economy values for a model type. 600.209-08 Section 600.209-08 Protection of Environment... MOTOR VEHICLES Procedures for Calculating Fuel Economy and Carbon-Related Exhaust Emission Values § 600.209-08 Calculation of vehicle-specific 5-cycle fuel economy values for a model type. (a) Base level....

  10. 40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-cycle fuel economy values for a model type. 600.209-08 Section 600.209-08 Protection of Environment... MOTOR VEHICLES Procedures for Calculating Fuel Economy and Carbon-Related Exhaust Emission Values § 600.209-08 Calculation of vehicle-specific 5-cycle fuel economy values for a model type. (a) Base level....

  11. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Thirty-two jet and diesel fuel samples of varying chemical composition and physical properties were prepared from oil shale and coal syncrudes. Hydrocarbon types in these samples were determined by a fluorescent indicator adsorption analysis, and the results from three laboratories are presented and compared. Two methods of rapid high performance liquid chromatography were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  12. Recovery of Technetium and Iodine from Spent ATW TRISO Type Fuels.

    SciTech Connect

    Schroeder, N. C.; Attrep, Moses

    2001-01-01

    The Accelerator Transmutation of Waste (ATW) program is being developed to determine the feasibility of separating and transmutating the transactinides (Pu-Cm) and long-lived fission product (99Tc and 129I) from spent LWR fuel. Several types of ATW fuels have been suggested to transmutate the Pu-Cm fraction including TRISO type fuels. An ATW TRISO fuel would consist of a Pu-Cm oxide kernel surrounded by several layers of pyrolytic carbon, a layer of SiC, and an outer layer of pyrolytic carbon. Processing of the spent ATW fuel would involve the crush, burn, and leach approach used on normal TRISO fuels. This report describes experiments that determine the potential behavior of the two long-lived fission products, 99Tc and 129I, in this processing. Iodine can be removed and trapped during the burning of the carbon from the fuel. Some technetium may volatilize in the latter stages of the burn but the bulk of it will have to be recovered after dissolution of the oxide residue.

  13. Effects of patch size and type of coffee matrix on ithomiine butterfly diversity and dispersal in cloud-forest fragments.

    PubMed

    Muriel, Sandra B; Kattan, Gustavo H

    2009-08-01

    Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that

  14. Swelling of U(Mo)–Al(Si) dispersion fuel under irradiation – Non-destructive analyses of the LEONIDAS E-FUTURE plates

    SciTech Connect

    S. Van den Berghe; Y. Parthoens; F. Charollais; Y. S. Kim; A. Leenaers; E. Koonen; V. Kuzminov; P. Lemoine; C. Jarousse; H. Guyon; D. Wachs; D. Keiser, Jr.; A. Robinson; J. Stevens; G. Hofman

    2012-11-01

    In the framework of the elimination of High-Enriched Uranium (HEU) from the civil circuit, the search for an appropriate fuel to replace the high-enriched research reactor fuel in those reactors that currently still require it for their operation has led to the development of a U–7 wt.%Mo alloy based dispersion fuel with an Al–Si matrix. The European LEONIDAS program, joining SCK-CEN, ILL, CEA and AREVA-CERCA, is aimed at the qualification of such a fuel for the use in high power conditions. The first experiment of the program, designated E-FUTURE, was performed to select the appropriate matrix Si concentration and fuel plate post-production heat treatment parameters for further qualification. It consisted of the irradiation of four distinct (4% and 6% Si, 3 different heat treatments) full size, flat fuel plates in the BR2 reactor. The irradiation conditions were relatively severe: 470 W/cm2 peak BOL power, with an approximate 70% 235U peak burnup.

  15. Swelling of U(Mo)-Al(Si) dispersion fuel under irradiation - Non-destructive analyses of the LEONIDAS E-FUTURE plates

    NASA Astrophysics Data System (ADS)

    Van den Berghe, S.; Parthoens, Y.; Charollais, F.; Kim, Y. S.; Leenaers, A.; Koonen, E.; Kuzminov, V.; Lemoine, P.; Jarousse, C.; Guyon, H.; Wachs, D.; Keiser, D., Jr.; Robinson, A.; Stevens, J.; Hofman, G.

    2012-11-01

    In the framework of the elimination of High-Enriched Uranium (HEU) from the civil circuit, the search for an appropriate fuel to replace the high-enriched research reactor fuel in those reactors that currently still require it for their operation has led to the development of a U-7 wt.%Mo alloy based dispersion fuel with an Al-Si matrix. The European LEONIDAS program, joining SCK•CEN, ILL, CEA and AREVA-CERCA, is aimed at the qualification of such a fuel for the use in high power conditions. The first experiment of the program, designated E-FUTURE, was performed to select the appropriate matrix Si concentration and fuel plate post-production heat treatment parameters for further qualification. It consisted of the irradiation of four distinct (4% and 6% Si, 3 different heat treatments) full size, flat fuel plates in the BR2 reactor. The irradiation conditions were relatively severe: 470 W/cm2 peak BOL power, with a ˜70% 235U peak burnup.

  16. High dispersion spectroscopy of solar-type superflare stars. I. Temperature, surface gravity, metallicity, and vsin i

    NASA Astrophysics Data System (ADS)

    Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Nogami, Daisaku; Shibata, Kazunari

    2015-06-01

    We conducted high-dispersion spectroscopic observations of 50 superflare stars with Subaru High Dispersion Spectrograph (HDS), and measured the stellar parameters of them. These 50 targets were selected from the solar-type (G-type main sequence) superflare stars that we had discovered from the Kepler photometric data. As a result of these spectroscopic observations, we found that more than half (34) of our 50 targets have no evidence of binary systems. We then estimated the effective temperature (Teff), surface gravity (log g), metallicity ([Fe/H]), and projected rotational velocity (vsin i) of these 34 superflare stars on the basis of our spectroscopic data. The accuracy of our estimations is higher than that of the Kepler Input Catalog (KIC) values, and the differences between our values and KIC values [(ΔTeff)rms ˜ 219 K, (Δlog g)rms ˜ 0.37 dex, and (Δ[Fe/H])rms ˜ 0.46 dex] are comparable to the large uncertainties and systematic differences of KIC values reported by the previous researchers. We confirmed that the estimated Teff and log g values of the 34 superflare stars are roughly in the range of solar-type stars. In particular, these parameters and the brightness variation period (P0) of nine of the stars are in the range of "Sun-like" stars (5600 ≤ Teff ≤ 6000 K, log g ≥ 4.0, and P0 > 10 d). Five of the 34 target stars are fast rotators (vsin i ≥ 10 km s-1), while 22 stars have relatively low vsin i values (vsin i < 5 km s-1). These results suggest that stars that have spectroscopic properties similar to the Sun can have superflares, and this supports the hypothesis that the Sun might cause a superflare.

  17. 40 CFR Table C-1 to Subpart C of... - Default CO2 Emission Factors and High Heat Values for Various Types of Fuel

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Heat Values for Various Types of Fuel C Table C-1 to Subpart C of Part 98 Protection of Environment... Emission Factors and High Heat Values for Various Types of Fuel Default CO2 Emission Factors and High Heat Values for Various Types of Fuel Fuel type Default high heat value Default CO2 emission factor Coal...

  18. 40 CFR Table C-1 to Subpart C of... - Default CO2 Emission Factors and High Heat Values for Various Types of Fuel

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Heat Values for Various Types of Fuel C Table C-1 to Subpart C of Part 98 Protection of Environment... Emission Factors and High Heat Values for Various Types of Fuel Default CO2 Emission Factors and High Heat Values for Various Types of Fuel Fuel type Default high heat value Default CO2 emission factor Coal...

  19. Group-type hydrocarbon standards for high-performance liquid chromatographic analysis of middistillate fuels

    NASA Technical Reports Server (NTRS)

    Otterson, D. A.; Seng, G. T.

    1984-01-01

    A new high-performance liquid chromatographic (HPLC) method for group-type analysis of middistillate fuels is described. It uses a refractive index detector and standards that are prepared by reacting a portion of the fuel sample with sulfuric acid. A complete analysis of a middistillate fuel for saturates and aromatics (including the preparation of the standard) requires about 15 min if standards for several fuels are prepared simultaneously. From model fuel studies, the method was found to be accurate to within 0.4 vol% saturates or aromatics, and provides a precision of + or - 0.4 vol%. Olefin determinations require an additional 15 min of analysis time. However, this determination is needed only for those fuels displaying a significant olefin response at 200 nm (obtained routinely during the saturated/aromatics analysis procedure). The olefin determination uses the responses of the olefins and the corresponding saturates, as well as the average value of their refractive index sensitivity ratios (1.1). Studied indicated that, although the relative error in the olefins result could reach 10 percent by using this average sensitivity ratio, it was 5 percent for the fuels used in this study. Olefin concentrations as low as 0.1 vol% have been determined using this method.

  20. Chemical Kinetic Reaction Mechanisms for Combustion of Hydrocarbon and Other Types of Chemical Fuels

    DOE Data Explorer

    The central feature of the Combustion Chemistry project at LLNL is the development, validation, and application of detailed chemical kinetic reaction mechanisms for the combustion of hydrocarbon and other types of chemical fuels. For the past 30 years, LLNL's Chemical Sciences Division has built hydrocarbon mechanisms for fuels from hydrogen and methane through much larger fuels including heptanes and octanes. Other classes of fuels for which models have been developed include flame suppressants such as halons and organophosphates, and air pollutants such as soot and oxides of nitrogen and sulfur. Reaction mechanisms have been tested and validated extensively through comparisons between computed results and measured data from laboratory experiments (e.g., shock tubes, laminar flames, rapid compression machines, flow reactors, stirred reactors) and from practical systems (e.g., diesel engines, spark-ignition engines, homogeneous charge, compression ignition (HCCI) engines). These kinetic models are used to examine a wide range of combustion systems.

  1. A dynamic, dependent type system for nuclear fuel cycle code generation

    SciTech Connect

    Scopatz, A.

    2013-07-01

    The nuclear fuel cycle may be interpreted as a network or graph, thus allowing methods from formal graph theory to be used. Nodes are often idealized as nuclear fuel cycle facilities (reactors, enrichment cascades, deep geologic repositories). With the advent of modern object-oriented programming languages - and fuel cycle simulators implemented in these languages - it is natural to define a class hierarchy of facility types. Bright is a quasi-static simulator, meaning that the number of material passes through a facility is tracked rather than natural time. Bright is implemented as a C++ library that models many canonical components such as reactors, storage facilities, and more. Cyclus is a discrete time simulator, meaning that natural time is tracked through out the simulation. Therefore a robust, dependent type system was developed to enable inter-operability between Bright and Cyclus. This system is capable of representing any fuel cycle facility. Types declared in this system can then be used to automatically generate code which binds a facility implementation to a simulator front end. Facility model wrappers may be used either internally to a fuel cycle simulator or as a mechanism for inter-operating multiple simulators. While such a tool has many potential use cases it has two main purposes: enabling easy performance of code-to-code comparisons and the verification and the validation of user input.

  2. Spreading speeds and traveling waves for a nonlocal dispersal equation with convolution-type crossing-monostable nonlinearity

    NASA Astrophysics Data System (ADS)

    Zhang, Guo-Bao; Ma, Ruyun

    2014-10-01

    This paper is concerned with the traveling wave solutions and the spreading speeds for a nonlocal dispersal equation with convolution-type crossing-monostable nonlinearity, which is motivated by an age-structured population model with time delay. We first prove the existence of traveling wave solution with critical wave speed c = c*. By introducing two auxiliary monotone birth functions and using a fluctuation method, we further show that the number c = c* is also the spreading speed of the corresponding initial value problem with compact support. Then, the nonexistence of traveling wave solutions for c < c* is established. Finally, by means of the (technical) weighted energy method, we prove that the traveling wave with large speed is exponentially stable, when the initial perturbation around the wave is relatively small in a weighted norm.

  3. Microstructural evolution of U(Mo)–Al(Si) dispersion fuel under irradiation – Destructive analyses of the LEONIDAS E-FUTURE plates

    SciTech Connect

    A. Leenaers; S. Van den Berghe; J. Van Eyken; E. Koonen; F. Charollais; P. Lemoine; Y. Calzavara; H. Guyon; C. Jarousse; D. Geslin; D. Wachs; D. Keiser; A. Robinson; G. Hofman; Y. S. Kim

    2013-10-01

    Several irradiation experiments have confirmed the positive effect of adding Si to the matrix of an U(Mo) dispersion fuel plate on its in-pile irradiation behavior. E-FUTURE, the first experiment of the LEONIDAS program, was performed to select an optimum Si concentration and fuel plate heat treatment parameters for further qualification. It consisted of the irradiation of 4 distinct (regarding Si content and heat treatments), full size flat fuel plates in the BR2 reactor under bounding conditions (470 W/cm2 peak BOL power, approximately 70% peak burn-up). After the irradiation, the E-FUTURE plates were examined non-destructively and found to have pillowed in the highest burn-up positions. The destructive post-irradiation examination confirmed that the fuel evolves in a stable way up to a burn-up of 60%235U. Even in the deformed area (pillow) the U(Mo) fuel itself shows stable behavior and remaining matrix material was present. From the calculation of the volume fractions, the positive effect of a higher Si amount added to the matrix and the higher annealing temperature can be derived.

  4. High dispersion spectroscopy of solar-type superflare stars with Subaru/HDS

    NASA Astrophysics Data System (ADS)

    Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Nogami, Daisaku; Shibata, Kazunari

    2015-08-01

    Superflares are very large flares that release total energy 10-104 times greater than that of the biggest solar flares with energy of ~1032 erg. Recent Kepler-space-telescope observations found more than 1000 superflares on a few hundred solar-type stars (Maehara et al. 2012, Nature, 485, 478; Shibayama et al. 2013, ApJS, 209, 5). Such superflare stars show quasi-periodic brightness variations with the typical period of from one to a few tens of days . Such variations are thought to be caused by the rotation of the star with large starspots (Notsu et al. 2013, ApJ, 771, 127). However, spectroscopic observations are needed in order toconfirm whether the variation is really due to the rotation and whether superflares can occur on ordinary single stars similar to our Sun.We have carried out spectroscopic observations for 50 solar-type superflare stars with Subaru/HDS. As a result, more than half (34 stars) of the target stars show no evidence of the binary system, and we confirmed stellar atmospheric parameters of these stars are roughly in the range of solar-type stars on the basis of our spectroscopic data.We then conducted the detailed analyses for these 34 stars. First, the value of the "v sin i" (projected rotational velocity) measured from spectroscopic results is consistent with the rotational velocity estimated from the brightness variation. Second, there is a correlation between the amplitude of the brightness variation and the intensity of Ca II IR triplet line. All the targets expected to have large starspots because of their large amplitude of the brightness variation show high chromospheric activities compared to the Sun. These support that the brightness variation discussed above is explained by the rotation of a star with large starspots.Reference:Notsu et al. 2015a & 2015b, PASJ in press (arXiv:1412.8243, 1412.8245)Nogami et al. 2014, PASJ, 66, L4Notsu et al. 2013, PASJ, 65, 112

  5. Comparison of Coriolis and turbine-type flowmeters for fuel measurement in gas turbine testing

    SciTech Connect

    MacLeod, J.D.; Grabe, W.

    1995-01-01

    The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. The MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine-type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference, and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeter. Results indicate that the agreement between Coriolis and turbine-type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturer`s specification. Even a significant variation in fuel density (10 percent), and viscosity (300 percent) did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.

  6. 40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-cycle fuel economy values for a model type. 600.209-08 Section 600.209-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Procedures for Calculating Fuel Economy and Carbon-Related Exhaust Emission Values...

  7. 14 CFR 26.33 - Holders of type certificates: Fuel tank flammability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... in the Airworthiness Limitations Section (ALS) of the ICA required by 14 CFR 25.1529 or paragraph (f... installation of fuel tank IMM that comply with 14 CFR 25.981(c) in effect on December 26, 2008. (e... 27, 2010, holders of type certificates affected by this section must establish an ALS of...

  8. 14 CFR 26.33 - Holders of type certificates: Fuel tank flammability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... in the Airworthiness Limitations Section (ALS) of the ICA required by 14 CFR 25.1529 or paragraph (f... installation of fuel tank IMM that comply with 14 CFR 25.981(c) in effect on December 26, 2008. (e... 27, 2010, holders of type certificates affected by this section must establish an ALS of...

  9. 40 CFR 600.207-86 - Calculation of fuel economy values for a model type.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) The manufacturer shall supply total model year sales projections for each car line/vehicle... a model type. 600.207-86 Section 600.207-86 Protection of Environment ENVIRONMENTAL PROTECTION... Procedures for Calculating Fuel Economy and Carbon-Related Exhaust Emission Values for 1977 and Later...

  10. 14 CFR 26.33 - Holders of type certificates: Fuel tank flammability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in the Airworthiness Limitations Section (ALS) of the ICA required by 14 CFR 25.1529 or paragraph (f... installation of fuel tank IMM that comply with 14 CFR 25.981(c) in effect on December 26, 2008. (e) Instructions for Continued Airworthiness (ICA). No later than December 27, 2010, holders of type...

  11. 14 CFR 26.33 - Holders of type certificates: Fuel tank flammability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... in the Airworthiness Limitations Section (ALS) of the ICA required by 14 CFR 25.1529 or paragraph (f... installation of fuel tank IMM that comply with 14 CFR 25.981(c) in effect on December 26, 2008. (e) Instructions for Continued Airworthiness (ICA). No later than December 27, 2010, holders of type...

  12. Dynamics of the flammable plumes resulting from the convective dispersion of a fixed mass of the buoyant gaseous fuel, methane, into air.

    PubMed

    Fardisi, S; Karim, Ghazi A

    2009-08-15

    The dynamics of the dispersion of a fixed mass of the buoyant fuel, methane, when exposed with a negligible pressure difference to overlaying air within vertical cylindrical enclosures open to the atmosphere is investigated. Features of the formation and dispersion of flammable mixtures created by the gas dissipation were examined using a 3D CFD model. For the cases considered, the lean-flammable mixture boundary appears to travel mainly at a near constant rate while the rich limit front shows a more chaotic behaviour. The corresponding simulation using an axis-symmetrical 2D model tended to under-predict the dynamics of the lean and rich boundaries, for the cases considered. PMID:19237243

  13. Electrostatic Dispersion and Evaporation of Dense and Dilute Clusters of Drops of High-Energy Fuel For Soot Control

    NASA Technical Reports Server (NTRS)

    Bellan, J.; Harstad, K.

    1997-01-01

    The high-energy-density (HED) fuels developed under U.S. Navy sponsorship as a replacement for conventional liquid fuels, in its missile propulsion systems have the drawback of high soot propensity: this makes misiles visible and thus strategically unacceptabel.

  14. Differences in the effects of fuel oil and oil dispersant, and three polychlorinated biphenyls on fin regeneration in the Gulf Coast killifish, Fundulus grandis

    SciTech Connect

    Fingerman, S.W.

    1980-08-01

    Several environmental pollutants have been found to inhibit growth in animals. As a result of experiments performed in this laboratory on the long range effects of low levels of environmental pollutants on molting and limb regeneration in the fiddler crab, Uca pugilator and because animals in nature are rarely exposed to a single pollutant, a series of experiments was conducted to determine the effects, if any, of a single exposure to several pollutants, singly and in combination, on fin regeneration in the Gulf Coast killifish Fundulus grandis. The pollutants investigated were a fuel oil, an oil dispersant, and three polychlorinated biphenyls (PCBs).

  15. Dependence of the radiative forcing of the climate system on fossil fuel type

    NASA Astrophysics Data System (ADS)

    Nunez, L. I.

    2015-12-01

    Climate change mitigation strategies are greatly directed towards the reduction of CO2 emissions and other greenhouse gases from fossil fuel combustion to limit warming to 2º C in this century. For example, the Clean Power Plan aims to reduce CO2 emissions from the power sector by 32% of 2005 levels by 2030 by increasing power plant efficiency but also by switching from coal-fired power plants to natural gas-fired power plants. It is important to understand the impact of such fuel switching on climate change. While all fossil fuels emit CO2, they also emit other pollutants with varying effects on climate, health and agriculture. First, The emission of CO2 per joule of energy produced varies significantly between coal, oil and natural gas. Second, the complexity that the co-emitted pollutants add to the perturbations in the climate system necessitates the detangling of radiative forcing for each type of fossil fuel. The historical (1850-2011) net radiative forcing of climate as a function of fuel type (coal, oil, natural gas and biofuel) is reconstructed. The results reveal the significant dependence of the CO2 and the non-CO2 forcing on fuel type. The CO2 forcing per joule of energy is largest for coal. Radiative forcing from the co-emitted pollutants (black carbon, methane, nitrogen oxides, organic carbon, sulfate aerosols) changes the global mean CO2 forcing attributed to coal and oil significantly. For natural gas, the CO2-only radiative forcing from gas is increased by about 60% when the co-emitted pollutants are included.

  16. Coating-type three-dimensional acetate-driven microbial fuel cells.

    PubMed

    Yu, Jin; Tang, Yulan

    2015-08-01

    This study uses sodium acetate as fuel to construct bioelectricity in coating-type three-dimensional microbial fuel cells anode. The coating-type three-dimensional anode was constructed using iron net as structural support, adhering a layer of carbon felt as primary coating and using carbon powder and 30% PTFE solution mixture as coating. The efficiency of electricity production and wastewater treatment were analyzed for the three-dimensional acetate-fed (C2H3NaO2) microbial fuel cells with the various ratio of the coating mixture. The results showed that the efficiency of electricity production was significantly improved when using the homemade coating-type microbial fuel cells anode compared with the one without coating on the iron net, which the apparent internal resistance was decreased by 59.4% and the maximum power density was increased by 1.5 times. It was found the electricity production was greatly influenced by the ratio of the carbon powder and PTFE in the coating. The electricity production was the highest with apparent internal resistance of 190 Ω, and maximum power density of 5189.4 mW m(-3) when 750 mg of carbon powder and 10 ml of PTFE (i.e., ratio 75:1) was used in the coating. With the efficiency of electricity production, wide distribution and low cost of the raw materials, the homemade acetate-fed microbial fuel cells provides a valuable reference to the development of the composition microbial fuel cell anode production. PMID:25681073

  17. The influence of the types of marine fuel over the Energy Efficiency Operational Index

    NASA Astrophysics Data System (ADS)

    Acomi, Nicoleta; Acomi, Ovidiu

    2014-05-01

    One of the main concerns of our society is certainly the environment protection. The international efforts for maintaining the environment clean are various and this paper refers to the efforts in the maritime transport field. Marine pollution consists of the water pollution and also the air pollution. Regardless of the delay in recognizing the later type of pollution, it rapidly gains many organizations to argue on it. The first step was including a dedicated annex (Annex VI) in the International Convention for the Prevention of Pollution from Ships, in 1997, which seeks to minimize the airborne emissions from ships. In order to control and minimize the air pollution, the International Maritime Organization has also developed a series of measures for monitoring the emissions. These measures are grouped in three main directions: technical, operational and management related. The subject of our study is the concept of Energy Efficiency Operational Index (EEOI), developed to provide ship-owners with assistance in the process of establishing the emissions from ships in operation, and to suggest the methods for achieving their reduction. As a monitoring tool, EEOI represents the mass of CO2 emitted per unit of transport work. The actual CO2 emission from combustion of fuel on board a ship during each voyage is calculated by multiplying total fuel consumption for each type of fuel (e.g. diesel oil, gas oil, light fuel oil, heavy fuel oil, liquefied petroleum gas, liquefied natural gas) with the carbon to CO2 conversion factor for the fuel in question. The performed transport work is calculated by multiplying mass of cargo (tonnes, number of TEU/cars, or number of passengers) with the distance in nautical miles corresponding to the transport work done. Using the software developed by the author it will be emphasized the variation of the EEOI value for one vessel using different types of fuel for the voyage's legs (distance to discharge port, distance to loading port, the

  18. A Comparison of Fuel Sprays from Several Types of Injection Nozzles

    NASA Technical Reports Server (NTRS)

    Lee, Dana W

    1936-01-01

    This report presents the tests results of a series of tests made of the sprays from 14 fuel injection nozzles of 9 different types, the sprays being injected into air at atmospheric density and at 6 and 14 times atmospheric density. High-speed spark photographs of the sprays from each nozzle at each air density were taken at the rate of 2,000 per second, and from them were obtained the dimensions of the sprays and the rates of spray-tip penetration. The sprays were also injected against plasticine targets placed at different distances from the nozzles, and the impressions made in the plasticine were used as an indication of the distribution of the fuel within the spray. Cross-sectional sketches of the different types of sprays are given showing the relative sizes of the spray cores and envelopes. The characteristics of the sprays are compared and discussed with respect to their application to various types of engines.

  19. 14 CFR 291.44 - BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false BTS Schedule P-12(a), Fuel Consumption by... TRANSPORTATION Reporting Rules § 291.44 BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity. (a) For the purposes of BTS schedule P-12(a), type of service shall be either scheduled service...

  20. 14 CFR 291.44 - BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false BTS Schedule P-12(a), Fuel Consumption by... TRANSPORTATION Reporting Rules § 291.44 BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity. (a) For the purposes of BTS schedule P-12(a), type of service shall be either scheduled service...

  1. 14 CFR 291.44 - BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false BTS Schedule P-12(a), Fuel Consumption by... TRANSPORTATION Reporting Rules § 291.44 BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity. (a) For the purposes of BTS schedule P-12(a), type of service shall be either scheduled service...

  2. 14 CFR 291.44 - BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false BTS Schedule P-12(a), Fuel Consumption by... TRANSPORTATION Reporting Rules § 291.44 BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity. (a) For the purposes of BTS schedule P-12(a), type of service shall be either scheduled service...

  3. 14 CFR 291.44 - BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false BTS Schedule P-12(a), Fuel Consumption by... TRANSPORTATION Reporting Rules § 291.44 BTS Schedule P-12(a), Fuel Consumption by Type of Service and Entity. (a) For the purposes of BTS schedule P-12(a), type of service shall be either scheduled service...

  4. Fog dispersion

    NASA Technical Reports Server (NTRS)

    Frost, W.; Christensen, L. S.; Collins, F. G.; Camp, D. W.

    1980-01-01

    A study of economically viable techniques for dispersing warm fog at commercial airports is presented. Five fog dispersion techniques are examined: evaporation suppression, downwash, mixing, seeding with hygroscopic material, thermal techniques, and charged particle techniques. Thermal techniques, although effective, were found to be too expensive for routine airport operations, and detrimental to the environment. Seeding or helicopter downwash are practical for small-scale or temporary fog clearing, but are probably not useful for airport operations on a routine basis. Considerable disagreement exists on the capability of charged particle techniques, which stems from the fact that different assumptions and parameter values are used in the analytical models. Recommendations resulting from the review of this technique are listed, and include: experimental measurements of the parameters in question; a study to ascertain possible safety hazards, such as increased electrical activity or fuel ignition during refueling operations which could render charged particle techniques impractical; and a study of a single charged particle generator.

  5. Ceramic anode catalyst for dry methane type molten carbonate fuel cell

    NASA Astrophysics Data System (ADS)

    Tagawa, T.; Yanase, A.; Goto, S.; Yamaguchi, M.; Kondo, M.

    Oxide catalyst materials for methane oxidation were examined in order to develop the anode electrode for molten carbonate type fuel cell (MCFC). As a primary selection, oxides such as lanthanum (La 2O 3) and samarium (Sm 2O 3) were selected from screening experiments of TPD, TG and tubular reactor. Composite materials of these oxides with titanium fine powder were assembled into a cell unit for MCFC as the anode electrode. Steady-state activities were observed with these anode electrode materials when hydrogen was used as a fuel. When methane was directly charged to anode as a fuel (dry methane operation), a power generation with steady state was observed on both lanthanum and samarium composites after gradual decrease of open circuit electromotive force (OCV) and closed circuit current (CCI). The steady-state activity held as long as 144 h of continuous operation.

  6. CHARACTERISTICS OF SPILLED OILS, FUELS, AND PETROLEUM PRODUCTS: 3A. SIMULATION OF OIL SPILLS AND DISPERSANTS UNDER CONDITIONS OF UNCERTAINTY

    EPA Science Inventory

    At the request of the US EPA Oil Program Center, ERD is developing an oil spill model that focuses on fate and transport of oil components under various response scenarios. This model includes various simulation options, including the use of chemical dispersing agents on oil sli...

  7. Dispersion Analysis Research Tool

    Energy Science and Technology Software Center (ESTSC)

    1998-11-10

    The DART thermomechanical model, for the prediction of fission-product-induced swelling in aluminum dispersion fuels, calculates irradiation-induced fission gas bubbles as a function of fuel morphology. DART calculates the behavior of a rod, tube, or plate during closure of as-fabricated porosity, during which the fuel particle swelling is accommodated by the relatively soft aluminum matrix flowing into the existing porosity. The code also determines the subsequent macroscopic changes in rod diameter or plate/tube thickness caused bymore » additional fuel deformation processes. In addition, a calculation for the effect of irradiation on the thermal conductivity of the dispersion fuel, and for fuel restructuring and swelling due to the aluminum fuel reaction, amorphization, and recrystallization is included.« less

  8. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Results are given for the analysis of some jet and diesel fuel samples which were prepared from oil shale and coal syncrudes. Thirty-two samples of varying chemical composition and physical properties were obtained. Hydrocarbon types in these samples were determined by fluorescent indicator adsorption (FIA) analysis, and the results from three laboratories are presented and compared. Recently, rapid high performance liquid chromatography (HPLC) methods have been proposed for hydrocarbon group type analysis, with some suggestion for their use as a replacement of the FIA technique. Two of these methods were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  9. VELOCITY DISPERSIONS AND STELLAR POPULATIONS OF THE MOST COMPACT AND MASSIVE EARLY-TYPE GALAXIES AT REDSHIFT {approx}1

    SciTech Connect

    Martinez-Manso, Jesus; Guzman, Rafael; Barro, Guillermo; Cardiel, Nicolas; Gallego, Jesus; Cenarro, Javier; Perez-Gonzalez, Pablo; Sanchez-Blazquez, Patricia; Trujillo, Ignacio; Balcells, Marc; Hempel, Angela; Prieto, Mercedes

    2011-09-10

    We present Gran-Telescopio-Canarias/OSIRIS optical spectra of four of the most compact and massive early-type galaxies (ETGs) in the Groth Strip Survey at redshift z {approx} 1, with effective radii R{sub e} = 0.5-2.4 kpc and photometric stellar masses M{sub *} = (1.2-4) x 10{sup 11} M{sub sun}. We find that these galaxies have velocity dispersions {sigma} = 156-236 km s{sup -1}. The spectra are well fitted by single stellar population models with approximately 1 Gyr of age and solar metallicity. We find that (1) the dynamical masses of these galaxies are systematically smaller by a factor of {approx}6 than the published stellar masses using BRIJK photometry, and (2) when estimating stellar masses as 0.7x M{sub dyn}, a combination of passive luminosity fading with mass/size growth due to minor mergers can plausibly evolve our objects to match the properties of the local population of ETGs.

  10. THE GEMINI SPECTRAL LIBRARY OF NEAR-IR LATE-TYPE STELLAR TEMPLATES AND ITS APPLICATION FOR VELOCITY DISPERSION MEASUREMENTS

    SciTech Connect

    Winge, Claudia

    2009-11-01

    We present a spectroscopic library of late spectral type stellar templates in the near-IR range 2.15-2.42 {mu}m, at R = 5300-5900 resolution, oriented to support stellar kinematics studies in external galaxies, such as the direct determination of the masses of supermassive black holes in nearby active (or non-active) galaxies. The combination of high spectral resolution and state-of-the-art instrumentation available in 8 m class telescopes has made the analysis of circumnuclear stellar kinematics using the near-IR CO band heads one of the most used techniques for such studies, and this library aims to provide the supporting data sets required by the higher spectral resolution and larger spectral coverage currently achieved with modern near-IR spectrographs. Examples of the application for kinematical analysis are given for data obtained with two Gemini instruments, but the templates can be easily adjusted for use with other near-IR spectrographs at similar or lower resolution. The example data sets are also used to revisit the 'template mismatch' effect and the dependence of the velocity dispersion values obtained from the fitting process with the characteristics of the stellar templates. The library is available in electronic form from the Gemini Web pages.

  11. Development and Characterization of Gas Diffusion Layer Using Carbon Slurry Dispersed by Ammonium Lauryl Sulfate for Proton Exchange Member Fuel Cells

    NASA Astrophysics Data System (ADS)

    Villacorta, Rashida

    Gas diffusion layers (GDLs) are a critical and essential part of proton exchange membrane fuel cells (PEMFCs). They carry out various important functions such as transportation of reactants to and from the reaction sites. The material properties and structural characteristics of the substrate and the microporous layer strongly influence fuel cell performance. The microporous layer of the GDLs was fabricated with the carbon slurry dispersed in water containing ammonium lauryl sulfate (ALS) using the wire rod coating method. GDLs were fabricated with different materials to compose the microporous layer and evaluated the effects on PEMFC power output performance. The consistency of the carbon slurry was achieved by adding 25 wt. % of PTFE, a binding agent with a 75:25 ratio of carbon (Pureblack and vapor grown carbon fiber). The GDLs were investigated in PEMFC under various relative humidity (RH) conditions using H2/O2 and H2/Air. GDLs were also fabricated with the carbon slurry dispersed in water containing sodium dodecyl sulfate (SDS) and multiwalled carbon nanotubes (MWCNTs) with isopropyl alcohol (IPA) based for fuel cell performance comparison. MWCNTs and SDS exhibits the highest performance at 60% and 70% RH with a peak power density of 1100 mW.cm-2 and 850 mW.cm-2 using air and oxygen as an oxidant. This means that the gas diffusion characteristics of these two samples were optimum at 60 and 70 % RH with high limiting current density range. It was also found that the composition of the carbon slurry, specifically ALS concentration has the highest peak power density of 1300 and 500mW.cm-2 for both H2/O 2 and H2/Air at 100% RH. However, SDS and MWCNTs demonstrates the lowest power density using air and oxygen as an oxidants at 100% RH.

  12. Annealing tests of in-pile irradiated oxide coated U-Mo/Al-Si dispersed nuclear fuel

    NASA Astrophysics Data System (ADS)

    Zweifel, T.; Valot, Ch.; Pontillon, Y.; Lamontagne, J.; Vermersch, A.; Barrallier, L.; Blay, T.; Petry, W.; Palancher, H.

    2014-09-01

    U-Mo/Al based nuclear fuels have been worldwide considered as a promising high density fuel for the conversion of high flux research reactors from highly enriched uranium to lower enrichment. In this paper, we present the annealing test up to 1800 °C of in-pile irradiated U-Mo/Al-Si fuel plate samples. More than 70% of the fission gases (FGs) are released during two major FG release peaks around 500 °C and 670 °C. Additional characterisations of the samples by XRD, EPMA and SEM suggest that up to 500 °C FGs are released from IDL/matrix interfaces. The second peak at 670 °C representing the main release of FGs originates from the interaction between U-Mo and matrix in the vicinity of the cladding.

  13. Dermal exposure to jet fuel suppresses delayed-type hypersensitivity: a critical role for aromatic hydrocarbons.

    PubMed

    Ramos, Gerardo; Limon-Flores, Alberto Yairh; Ullrich, Stephen E

    2007-12-01

    Dermal exposure to military (JP-8) and/or commercial (Jet-A) jet fuel suppresses cell-mediated immune reactions. Immune regulatory cytokines and biological modifiers, including platelet activating factor (PAF), prostaglandin E(2), and interleukin-10, have been implicated in the pathway of events leading to immune suppression. It is estimated that approximately 260 different hydrocarbons are found in jet fuel, and the exact identity of the active immunotoxic agent(s) is unknown. The recent availability of synthetic jet fuel (S-8), which is refined from natural gas, and is devoid of aromatic hydrocarbons, made it feasible to design experiments to address this problem. Here we tested the hypothesis that the aromatic hydrocarbons present in jet fuel are responsible for immune suppression. We report that applying S-8 to the skin of mice does not upregulate the expression of epidermal cyclooxygenase-2 (COX-2) nor does it induce immune suppression. Adding back a cocktail of seven of the most prevalent aromatic hydrocarbons found in jet fuel (benzene, toluene, ethylbenzene, xylene, 1,2,4-trimethlybenzene, cyclohexylbenzene, and dimethylnaphthalene) to S-8 upregulated epidermal COX-2 expression and suppressed a delayed-type hypersensitivity (DTH) reaction. Injecting PAF receptor antagonists, or a selective cycloozygenase-2 inhibitor into mice treated with S-8 supplemented with the aromatic cocktail, blocked suppression of DTH, similar to data previously reported using JP-8. These findings identify the aromatic hydrocarbons found in jet fuel as the agents responsible for suppressing DTH, in part by the upregulation of COX-2, and the production of immune regulatory factors and cytokines. PMID:17890764

  14. Progress in the R and D Project on Oxide Dispersion Strengthened and Precipitation Hardened Ferritic Steels for Sodium Cooled Fast Breeder Reactor Fuels

    SciTech Connect

    Kaito, Takeji; Ohtsuka, Satoshi; Inoue, Masaki

    2007-07-01

    High burnup capability of sodium cooled fast breeder reactor (SFR) fuels depends significantly on irradiation performance of their component materials. Japan Atomic Energy Agency (JAEA) has been developing oxide dispersion strengthened (ODS) ferritic steels and a precipitation hardened (PH) ferritic steel as the most prospective materials for fuel pin cladding and duct tubes, respectively. Technology for small-scale manufacturing is already established, and several hundreds of ODS steel cladding tubes and dozens of PH steel duct tubes were successfully produced. We will step forward to develop manufacturing technology for mass production to supply these steels for future SFR fuels. Mechanical properties of the products were examined by out-of-pile and in-pile tests including material irradiation tests in the experimental fast reactor JOYO and foreign fast reactors. The material strength standards (MSSs) were tentatively compiled in 2005 for ODS steels and in 1993 for PH steel. In order to upgrade the MSSs and to demonstrate high burnup capability of the materials, we will perform a series of irradiation tests in BOR-60 and JOYO until 2015 and contribute to design study for a demonstration SFR of which operation is expected after 2025. (authors)

  15. Ultramassive dense early-type galaxies: Velocity dispersions and number density evolution since z = 1.6

    NASA Astrophysics Data System (ADS)

    Gargiulo, A.; Saracco, P.; Tamburri, S.; Lonoce, I.; Ciocca, F.

    2016-08-01

    Aims: We investigate the stellar mass assembly history of ultramassive (M⋆ ≳ 1011M⊙) dense (Σ = M⋆/2πRe2> 2500M⊙ pc-2) early-type galaxies (ETGs, elliptical and spheroidal galaxies) selected on basis of visual classification over the last 9 Gyr. Methods: We traced the evolution of the comoving number density ρ of ultramassive dense ETGs and compared their structural (effective radius Re and stellar mass M⋆) and dynamical (velocity dispersion σe) parameters over the redshift range 0 < z < 1.6. We derived the number density ρ at 1.6 dispersion measurements are available. For four of these ETGs (plus one at z = 1.91), we present previously unpublished estimates of velocity dispersion, based on optical VLT-FORS2 spectra. We probe the intermediate redshift range (0.2 ≲ z ≲ 0.9) and the local Universe with different ETGs samples. Results: We find that the comoving number density of ultramassive dense ETGs evolves with z as ρ(z) ∝ (1 + z)0.3 ± 0.8 implying a decrease of ~25% of the population of ultramassive dense ETGs since z = 1.6. By comparing the structural and dynamical properties of high-z ultramassive dense ETGs over the range 0 ≲ z < 1.6 in the [Re, M⋆, σe] plane, we find that all of the ETGs of the high-z sample have counterparts with similar properties in the local Universe. This implies either that the majority (~70%) of ultramassive dense ETGs already completed the assembly and shaping at ⟨ z ⟩ = 1.4, or that, if a significant portion of dense ETGs evolves in size, new

  16. Opportunity fuels

    SciTech Connect

    Lutwen, R.C.

    1994-12-31

    Opportunity fuels - fuels that can be converted to other forms of energy at lower cost than standard fossil fuels - are discussed in outline form. The type and source of fuels, types of fuels, combustability, methods of combustion, refinery wastes, petroleum coke, garbage fuels, wood wastes, tires, and economics are discussed.

  17. Energy-dispersive spectroscopy and electron backscatter diffraction analysis of isothermally aged SAF 2507 type superduplex stainless steel

    NASA Astrophysics Data System (ADS)

    Dobranszky, J.; Szabo, P. J.; Berecz, T.; Hrotko, V.; Portko, M.

    2004-10-01

    Due to thermal effects, several precipitation and segregation processes are known in duplex stainless steels. These microstructural changes influence both of the original phases, but in different ways. Isothermal ageing in a large range of temperature was performed on SAF 2507 type steel. The temperature range was 300-1000 °C, the ageing time was between 100 s and 24 h. This paper discusses the results of ageing at 900 °C. Microstructural changes were investigated by electron microscopy, energy-dispersive spectroscopy and electron backscattered diffraction analysis. This technique allowed the determination of the microstructure of the secondary austenite and sigma phase and their mutual orientation properties. Beside this, thermoelectric power measurements were also performed, which gave information about the kinetics of the precipitation process. Results showed that sigma-phase precipitation started right after 200 s in the case of annealed steel, and faster than 100 s in the cold-rolled state. After 5000 s, the delta-ferrite disappeared. Chemical composition of sigma phase was independent on the ageing time. A small decrease in nickel content was observed with a slight increase of Cr content. Small amount of chi phase had also been observed on the ferrite-ferrite boundaries, but later they changed into sigma phase. Similarly to sigma phase, chi phase showed significant phosphorus enrichment. During ageing, small chrome nitride precipitates developed, which amount increased in time, and some vanadium could be measured in them. The orientation relationship between austenite and sigma phase deviated from Nenno-orientationship with about 24°, and seems to form a [110]‖[310] relationship, which was characteristic right from the beginning of the process, and remains more or less constant.

  18. Verifying the Cosmological Utility of Type Ia Supernovae:Implications of a Dispersion in the Ultraviolet Spectra

    SciTech Connect

    Ellis, R.S.; Sullivan, M.; Nugent, P.E.; Howell, D.A.; Gal-Yam,A.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; Carlberg, R.G.; Conley,A.; Fouchez, D.; Guy, J.; Hardin, D.; Hook, I.; Pain, R.; Perrett, K.; Pritchet, C.J.; Regnault, N.

    2007-11-02

    We analyze the mean rest-frame ultraviolet (UV) spectrum ofType Ia Supernovae(SNe) and its dispersion using high signal-to-noiseKeck-I/LRIS-B spectroscopyfor a sample of 36 events at intermediateredshift (z=0.5) discoveredby the Canada-France-Hawaii TelescopeSupernova Legacy Survey (SNLS). Weintroduce a new method for removinghost galaxy contamination in our spectra,exploiting the comprehensivephotometric coverage of the SNLS SNe and theirhost galaxies, therebyproviding the first quantitative view of the UV spectralproperties of alarge sample of distant SNe Ia. Although the mean SN Ia spectrumhas notevolved significantly over the past 40 percent of cosmic history,preciseevolutionary constraints are limited by the absence of acomparable sample ofhigh quality local spectra. The mean UV spectrum ofour z 0.5 SNe Ia and itsdispersion is tabulated for use in futureapplications. Within the high-redshiftsample, we discover significant UVspectral variations and exclude dust extinctionas the primary cause byexamining trends with the optical SN color. Although progenitormetallicity may drive some of these trends, the variations we see aremuchlarger than predicted in recent models and do not follow expectedpatterns.An interesting new result is a variation seen in the wavelengthof selected UVfeatures with phase. We also demonstrate systematicdifferences in the SN Iaspectral features with SN lightcurve width inboth the UV and the optical. Weshow that these intrinsic variations couldrepresent a statistical limitation in thefuture use of high-redshift SNeIa for precision cosmology. We conclude thatfurther detailed studies areneeded, both locally and at moderate redshift wherethe rest-frame UV canbe studied precisely, in order that future missions canconfidently beplanned to fully exploit SNe Ia as cosmological probes.

  19. TRACKING THE EMISSION OF CARBON DIOXIDE BY NATION, SECTOR, AND FUEL TYPE: A TRACE GAS ACCOUNTING SYSTEM (TGAS)

    EPA Science Inventory

    The paper describes a new way to estimate an efficient econometric model of global emissions of carbon dioxide (CO2) by nation, sector, and fuel type. Equations for fuel intensity are estimated for coal, oil, natural gas, electricity, and heat for six sectors: agricultural, indus...

  20. Installation, maintenance and operating manual for the Lucas-type fuel injection system of the 3 B rotary engine

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The installation procedure, maintenance, adjustment and operation of a Lucas type fuel injection system for 13B rotary racing engine is outlined. Components of the fuel injection system and installation procedure and notes are described. Maintenance, adjustment, and operation are discussed.

  1. The influence of weather and fuel type on the fuel composition of the area burned by forest fires in Ontario, 1996-2006.

    PubMed

    Podur, Justin J; Martell, David L

    2009-07-01

    Forest fires are influenced by weather, fuels, and topography, but the relative influence of these factors may vary in different forest types. Compositional analysis can be used to assess the relative importance of fuels and weather in the boreal forest. Do forest or wild land fires burn more flammable fuels preferentially or, because most large fires burn in extreme weather conditions, do fires burn fuels in the proportions they are available despite differences in flammability? In the Canadian boreal forest, aspen (Populus tremuloides) has been found to burn in less than the proportion in which it is available. We used the province of Ontario's Provincial Fuels Database and fire records provided by the Ontario Ministry of Natural Resources to compare the fuel composition of area burned by 594 large (>40 ha) fires that occurred in Ontario's boreal forest region, a study area some 430,000 km2 in size, between 1996 and 2006 with the fuel composition of the neighborhoods around the fires. We found that, over the range of fire weather conditions in which large fires burned and in a study area with 8% aspen, fires burn fuels in the proportions that they are available, results which are consistent with the dominance of weather in controlling large fires. PMID:19688931

  2. Fuel cells 101

    SciTech Connect

    Hirschenhofer, J.H.

    1999-07-01

    This paper discusses the various types of fuel cells, the importance of cell voltage, fuel processing for natural gas, cell stacking, fuel cell plant description, advantages and disadvantages of the types of fuel cells, and applications. The types covered include: polymer electrolyte fuel cell, alkaline fuel cell, phosphoric acid fuel cell; molten carbonate fuel cell, and solid oxide fuel cell.

  3. Assessing photocatalytic power of g-C3N4 for solar fuel production: A first-principles study involving quasi-particle theory and dispersive forces

    NASA Astrophysics Data System (ADS)

    Osorio-Guillén, J. M.; Espinosa-García, W. F.; Moyses Araujo, C.

    2015-09-01

    First-principles quasi-particle theory has been employed to assess catalytic power of graphitic carbon nitride, g-C3N4, for solar fuel production. A comparative study between g-h-triazine and g-h-heptazine has been carried out taking also into account van der Waals dispersive forces. The band edge potentials have been calculated using a recently developed approach where quasi-particle effects are taken into account through the GW approximation. First, it was found that the description of ground state properties such as cohesive and surface formation energies requires the proper treatment of dispersive interaction. Furthermore, through the analysis of calculated band-edge potentials, it is shown that g-h-triazine has high reductive power reaching the potential to reduce CO2 to formic acid, coplanar g-h-heptazine displays the highest thermodynamics force toward H2O/O2 oxidation reaction, and corrugated g-h-heptazine exhibits a good capacity for both reactions. This rigorous theoretical study shows a route to further improve the catalytic performance of g-C3N4.

  4. The effect of Cu2O nanoparticle dispersion on the thermoelectric properties of n-type skutterudites

    NASA Astrophysics Data System (ADS)

    Battabyal, M.; Priyadarshini, B.; Sivaprahasam, D.; Karthiselva, N. S.; Gopalan, R.

    2015-11-01

    We report the thermoelectric properties of Ba0.4Co4Sb12 and Sn0.4Ba0.4Co4Sb12 skutterudites dispersed with Cu2O nanoparticles. The samples were synthesized by ball milling and consolidated by spark plasma sintering. Dispersion of Cu2O is found to significantly influence the electrical resistivity and thermopower at high temperatures with a more pronounced effect on the electrical resistivity due to the energy filtering effect at the interface between Cu2O nanoparticles and a Ba0.4Co4Sb12 and Sn0.4Ba0.4Co4Sb12 matrix. At 573 K, the electrical resistivity of Ba0.4Co4Sb12 decreases from 5.01  ×  10-5 Ωm to 2.98  ×  10-5 Ωm upon dispersion of Cu2O. The dispersion of Cu2O reduces the thermal conductivity of the samples from 300 K and above by increasing the phonon scattering. The lowest observed thermal conductivity at 573 K is found to be 2.001 W mK-1 in Cu2O dispersed Ba0.4Co4Sb12 while it is 2.91 W mK-1 in the Ba0.4Co4Sb12 sample without Cu2O dispersion. Hence Cu2O dispersion plays a significant role in the thermoelectric properties and a maximum figure of merit (ZT ) ~ 0.92 is achieved in Cu2O dispersed Ba0.4Co4Sb12 at 573 K which is more than 200% compared to the pure Ba0.4Co4Sb12 sample. The results from nanoindentation experiments show that the Cu2O dispersed sample (Cu2O  +  Sn0.4Ba0.4Co4Sb11.6) has a higher reduced Young’s modulus (~139 GPa) than the pure Sn0.4Ba0.4Co4Sb11.6 sample (~128 GPa).

  5. Reactivity of atomically dispersed Pt(2+) species towards H2: model Pt-CeO2 fuel cell catalyst.

    PubMed

    Lykhach, Yaroslava; Figueroba, Alberto; Camellone, Matteo Farnesi; Neitzel, Armin; Skála, Tomáš; Negreiros, Fabio R; Vorokhta, Mykhailo; Tsud, Nataliya; Prince, Kevin C; Fabris, Stefano; Neyman, Konstantin M; Matolín, Vladimír; Libuda, Jörg

    2016-03-01

    The reactivity of atomically dispersed Pt(2+) species on the surface of nanostructured CeO2 films and the mechanism of H2 activation on these sites have been investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy in combination with density functional calculations. Isolated Pt(2+) sites are found to be inactive towards H2 dissociation due to high activation energy required for H-H bond scission. Trace amounts of metallic Pt are necessary to initiate H2 dissociation on Pt-CeO2 films. H2 dissociation triggers the reduction of Ce(4+) cations which, in turn, is coupled with the reduction of Pt(2+) species. The mechanism of Pt(2+) reduction involves reverse oxygen spillover and formation of oxygen vacancies on Pt-CeO2 films. Our calculations suggest the existence of a threshold concentration of oxygen vacancies associated with the onset of Pt(2+) reduction. PMID:26908194

  6. ATR LEU Monolithic Foil-Type Fuel with Integral Cladding Burnable Absorber – Neutronics Performance Evaluation

    SciTech Connect

    Gray Chang

    2012-03-01

    The Advanced Test Reactor (ATR), currently operating in the United States, is used for material testing at very high neutron fluxes. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting HEU driven reactor cores to low-enriched uranium (LEU) cores. The burnable absorber - 10B, was added in the inner and outer plates to reduce the initial excess reactivity, and to improve the peak ratio of the inner/outer heat flux. The present work investigates the LEU Monolithic foil-type fuel with 10B Integral Cladding Burnable Absorber (ICBA) design and evaluates the subsequent neutronics operating effects of this proposed fuel designs. The proposed LEU fuel specification in this work is directly related to both the RERTR LEU Development Program and the Advanced Test Reactor (ATR) LEU Conversion Project at Idaho National Laboratory (INL).

  7. Effects of fuel type and equivalence ratios on the flickering of triple flames

    SciTech Connect

    Sahu, K.B.; Kundu, A.; Ganguly, R.; Datta, A.

    2009-02-15

    An experimental study has been conducted in axisymmetric, co-flowing triple flames with different equivalence ratios of the inner and outer reactant streams (2<{phi}{sub in}<3 and 0{<=}{phi}{sub out}<0.7). Different fuel combinations, like propane/propane, propane/methane or methane/methane in the inner and outer streams respectively, have been used in the experiments. The structures of the triple flames have been compared for the different fuel combinations and equivalence ratios. The conditions under which triple flames exhibit oscillation have been identified. During the oscillation, the non-premixed flame and the outer lean premixed flame flicker strongly, while the inner rich premixed flame remains more or less stable. The flickering frequency has been evaluated through image processing and fast Fourier transform (FFT) of the average pixel intensity of the image frames. It is observed that, for all the fuel combinations, the frequency decreases with the increase in the outer equivalence ratio, while it is relatively invariant with the change in the inner equivalence ratio. However, an increase in the inner equivalence ratio affects the structure of the flame by increasing the heights of the inner premixed flame and non-premixed flame and also enlarges the yellow soot-laden zone at the tip of the inner flame. A scaling analysis of the oscillating flames has been performed based on the measured parameters, which show a variation of Strouhal number (St) with Richardson number (Ri) as St {proportional_to} Ri{sup 0.5}. The fuel type is found to have no influence on this correlation. (author)

  8. Effects of spent fuel types on offsite consequences of hypothetical accidents

    SciTech Connect

    Courtney, J. C.; Dwight, C. C.; Lehto, M. A.

    2000-02-18

    Argonne National Laboratory (ANL) conducts experimental work on the development of waste forms suitable for several types of spent fuel at its facility on the Idaho National Engineering and Environmental Laboratory (INEEL) located 48 km West of Idaho Falls, ID. The objective of this paper is to compare the offsite radiological consequences of hypothetical accidents involving the various types of spent nuclear fuel handled in nonreactor nuclear facilities. The highest offsite total effective dose equivalents (TEDEs) are estimated at a receptor located about 5 km SSE of ANL facilities. Criticality safety considerations limit the amount of enriched uranium and plutonium that could be at risk in any given scenario. Heat generated by decay of fission products and actinides does not limit the masses of spent fuel within any given operation because the minimum time elapsed since fissions occurred in any form is at least five years. At cooling times of this magnitude, fewer than ten radionuclides account for 99% of the projected TEDE at offsite receptors for any credible accident. Elimination of all but the most important nuclides allows rapid assessments of offsite doses with little loss of accuracy. Since the ARF (airborne release fraction), RF (respirable fraction), LPF (leak path fraction) and atmospheric dilution factor ({chi}/Q) can vary by orders of magnitude, it is not productive to consider nuclides that contribute less than a few percent of the total dose. Therefore, only {sup 134}Cs, {sup 137}Cs-{sup 137m}Ba, and the actinides significantly influence the offsite radiological consequences of severe accidents. Even using highly conservative assumptions in estimating radiological consequences, they remain well below current Department of Energy guidelines for highly unlikely accidents.

  9. 40 CFR 600.208-08 - Calculation of FTP-based and HFET-based fuel economy values for a model type.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... accordance with § 600.010-08(c)(1)(ii). (3) The manufacturer shall supply total model year sales projections...-based fuel economy values for a model type. 600.208-08 Section 600.208-08 Protection of Environment....208-08 Calculation of FTP-based and HFET-based fuel economy values for a model type. (a) Fuel...

  10. 40 CFR 600.208-08 - Calculation of FTP-based and HFET-based fuel economy values for a model type.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... accordance with § 600.010-08(c)(1)(ii). (3) The manufacturer shall supply total model year sales projections...-based fuel economy values for a model type. 600.208-08 Section 600.208-08 Protection of Environment....208-08 Calculation of FTP-based and HFET-based fuel economy values for a model type. (a) Fuel...