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Sample records for hot metal dephosphorization

  1. A Thermodynamic Model for Predicting Phosphorus Partition between CaO-based Slags and Hot Metal during Hot Metal Dephosphorization Pretreatment Process Based on the Ion and Molecule Coexistence Theory

    NASA Astrophysics Data System (ADS)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    A thermodynamic model for predicting phosphorus partition L P between a CaO-based slags and hot metal during hot metal dephosphorization pretreatment process has been developed based on the ion and molecule coexistence theory (IMCT), i.e., the IMCT- L P model. The reaction abilities of structural units or ion couples in the CaO-based slags have been represented by the calculated mass action concentrations N i through the developed IMCT- N i model based on the IMCT. The developed IMCT- L P model has been verified to be valid through comparing with the measured L P as well as the predicted L P by two reported L P models from the literature. Besides the total phosphorus partition L P between the CaO-based slag and hot metal, the respective phosphorus partitions L P, i of nine dephosphorization products as P2O5, 3FeO·P2O5, 4FeO·P2O5, 2CaO·P2O5, 3CaO·P2O5, 4CaO·P2O5, 2MgO·P2O5, 3MgO·P2O5, and 3MnO·P2O5 can also be accurately predicted by the developed IMCT- L P model. The formed 3CaO·P2O5 accounts for 99.20 pct of dephosphorization products comparing with the generated 4CaO·P2O5 for 0.08 pct. The comprehensive effect of CaO+Fe t O, which can be described by the mass percentage ratio (pct Fe t O)/(pct CaO) or the mass action concentration ratio N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}} as well as the mass percentage product (pct Fe t O) × (pct CaO) or the mass action concentration product N_{{{{Fe}}t {{O}}}}5 × N_{{CaO}}3 , controls dephosphorization ability of the CaO-based slags. A linear relationship of L P against (pct Fe t O)/(pct CaO) can be correlated compared with a parabolic relationship of L P against N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}, while the linear relationship of L P against (pct Fe t O) × (pct CaO) or N_{Fe}t O5 × N_{CaO}3 can be established. Thus, the mass percentage product (pct Fe t O) × (pct CaO) and the mass action concentration product N_{Fe}t O5 × N_{CaO}3 are recommended to represent the comprehensive effect of CaO+Fe t O on

  2. Spontaneous Emulsification of a Metal Drop Immersed in Slag Due to Dephosphorization: Surface Area Quantification

    NASA Astrophysics Data System (ADS)

    Assis, Andre N.; Warnett, Jason; Spooner, Stephen; Fruehan, Richard J.; Williams, Mark A.; Sridhar, Seetharaman

    2015-04-01

    When a chemical reaction occurs between two immiscible liquids, mass transfer is continuously taking place at the liquid-liquid interface. Several studies have shown that if the species being exchanged between the two liquids are surface-active, a very pronounced decrease in interfacial tension can occur which can lead to a phenomenon called spontaneous emulsification. In steelmaking, this behavior has been observed for several reactions that involve the transfer of impurities from molten steel to a molten-oxide slag but little quantification has been made. This work focuses on spontaneous emulsification due to the dephosphorization of a Fe-P drop immersed in a basic oxygen furnace type slag. An Au-image furnace attached to a confocal scanning laser microscope was used to rapidly heat and cool the samples at different times, and X-ray computerized tomography was used to perform the surface area calculations of the samples where the slag/steel reaction was allowed to occur for distinct times. The results show that the surface area of the metal drop rapidly increases by over one order of magnitude during the first 60 seconds of the reaction while the chemical reaction is occurring at a fast rate. Once the reaction slows down, approximately after 60 seconds, the droplets start to coalesce back together minimizing the surface area and returning to a geometry close to its equilibrium shape.

  3. Critical Evaluation of Prediction Models for Phosphorus Partition between CaO-based Slags and Iron-based Melts during Dephosphorization Processes

    NASA Astrophysics Data System (ADS)

    Yang, Xue-Min; Li, Jin-Yan; Chai, Guo-Ming; Duan, Dong-Ping; Zhang, Jian

    2016-08-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, the collected 16 models of equilibrium quotient k_{{P}} or phosphorus partition L_{{P}} between CaO-based slags and iron-based melts from the literature have been evaluated. The collected 16 models for predicting equilibrium quotient k_{{P}} can be transferred to predict phosphorus partition L_{{P}} . The predicted results by the collected 16 models cannot be applied to be criteria for evaluating k_{{P}} or L_{{P}} due to various forms or definitions of k_{{P}} or L_{{P}} . Thus, the measured phosphorus content [pct P] in a hot metal bath at the end point of the dephosphorization pretreatment process is applied to be the fixed criteria for evaluating the collected 16 models. The collected 16 models can be described in the form of linear functions as y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts the temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results of k_{{P}} or L_{{P}} . Thus, a general approach to developing the thermodynamic model for predicting equilibrium quotient k_{{P}} or phosphorus partition L P or [pct P] in iron-based melts during the dephosphorization process is proposed by revising the constant term in intercept c0 for the summarized 15 models except for Suito's model (M3). The better models with an ideal revising possibility or flexibility among the collected 16 models have been selected and recommended. Compared with the predicted result by the revised 15 models and Suito's model (M3), the developed IMCT- L_{{P}} model coupled with the proposed dephosphorization mechanism by the present authors can be applied to accurately predict phosphorus partition L_{{P}} with the lowest mean deviation δ_{{L_{{P}} }} of log L_{{P}} as 2.33, as

  4. Dephosphorization when using DRI

    SciTech Connect

    2005-09-21

    The increase in high quality steel production in electric arc furnaces (EAFs) requires the use of scrap substitute materials, such as Direct Reduced Iron (DRI) and Hot Briquetted Iron (HBI). Although DRI and HBI products have lower copper and nickel contents than most scrap materials, they can contain up to ten times more phosphorus. This project, led by Carnegie Mellon University’s Center for Iron and Steelmaking Research, improves the understanding of how phosphorus behaves when DRI and HBI melt.

  5. 13. Underside Span 1, Hot Metal Bridge on right toward ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Underside Span 1, Hot Metal Bridge on right toward Pier 1. - Monongahela Connecting Railroad Company, Hot Metal Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

  6. METHOD OF HOT ROLLING URANIUM METAL

    DOEpatents

    Kaufmann, A.R.

    1959-03-10

    A method is given for quickly and efficiently hot rolling uranium metal in the upper part of the alpha phase temperature region to obtain sound bars and sheets possessing a good surface finish. The uranium metal billet is heated to a temperature in the range of 1000 deg F to 1220 deg F by immersion iii a molten lead bath. The heated billet is then passed through the rolls. The temperature is restored to the desired range between successive passes through the rolls, and the rolls are turned down approximately 0.050 inch between successive passes.

  7. DEVELOPMENT OF METALLIC HOT GAS FILTERS

    SciTech Connect

    Anderson, I.E.; Gleeson, B.; Terpstra, R.L.

    2003-04-23

    Successful development of metallic filters with high temperature oxidation/corrosion resistance for fly ash capture is a key to enabling advanced coal combustion and power generation technologies. Compared to ceramic filters, metallic filters can offer increased resistance to impact and thermal fatigue, greatly improving filter reliability. A beneficial metallic filter structure, composed of a thin-wall (0.5mm) tube with uniform porosity (about 30%), is being developed using a unique spherical powder processing and partial sintering approach, combined with porous sheet rolling and resistance welding. Alloy choices based on modified superalloys, e.g., Ni-16Cr-4.5Al-3Fe (wt.%), are being tested in porous and bulk samples for oxide (typically alumina) scale stability in simulated oxidizing/sulfidizing atmospheres found in PFBC and IGCC systems at temperatures up to 850 C. Recent ''hanging o-ring'' exposure tests in actual combustion systems at a collaborating DOE site (EERC) have been initiated to study the combined corrosive effects from particulate deposits and hot exhaust gases. New studies are exploring the correlation between sintered microstructure, tensile strength, and permeability of porous sheet samples.

  8. 2. HOT METAL BRIDGE (ACROSS THE MONONGAHELA RIVER) AND CARRIE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. HOT METAL BRIDGE (ACROSS THE MONONGAHELA RIVER) AND CARRIE FURNACES No. 3 AND No. 4 FROM THE TOP OF WATER TOWER. THE EDGAR THOMSON WORKS IS VISIBLE BEYOND HOT METAL BRIDGE. Jet Lowe, Photographer, 1989. - U.S. Steel Homestead Works, Blast Furnace Plant, Along Monongahela River, Homestead, Allegheny County, PA

  9. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2015-12-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  10. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2016-09-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  11. Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

    NASA Astrophysics Data System (ADS)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-Ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in the CaO-based slags has been determined using the calculated comprehensive mass action concentration N_{{{{Fe}}t {{O}}}}{} of iron oxides by the ion and molecule coexistence theory (IMCT) for representing the reaction ability of Fe t O, i.e., activity of a_{{{{Fe}}t {{O}}}}{} . The collected ten models from the literature for predicting activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags have been evaluated based on the determined activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 by the IMCT as the criterion. The collected ten models of activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags can be described in the form of a linear function as log γ_{{{{P}}_{ 2} {{O}}_{ 5} }} ≡ y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results. Thus, a general approach for obtaining good prediction results of activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags is proposed by revising the constant term in intercept c0 for the collected ten models. The better models with an ideal revising possibility or flexibility in the collected ten models have been selected and recommended.

  12. 18. LOOKING EAST AT THE HOT METAL RELADLING PIT No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. LOOKING EAST AT THE HOT METAL RELADLING PIT No. 1 ON THE CHARGING AISLE OF THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  13. Emission of Visible Light by Hot Dense Metals

    SciTech Connect

    More, R.M.; Goto, M.; Graziani, F.; Ni, P.A.; Yoneda, H.

    2009-12-01

    We consider the emission of visible light by hot metal surfaces having uniform and non-uniform temperature distributions and by small droplets of liquid metal. The calculations employ a nonlocal transport theory for light emission, using the Kubo formula to relate microscopic current fluctuations to the dielectric function of the material. We describe a related algorithm for calculating radiation emission in particle simulation of hot fusion plasmas.

  14. HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. 1890), SOUTH PORTAL. THREE PIN CONNECTED CAMELBACK TRUSS SPANS, ONE SKEWED THROUGH TRUSS SPAN ON NORTH SIDE TRUSS BRIDGE, EAST OF HOT METAL BRIDGE BUILT BY AMERICAN BRIDGE COMPANY CA. 1910. (RIVETED MULTI-SPAN TRUSS). - Jones & Laughlin Steel Corporation, Pittsburgh Works, Morgan Billet Mill Engine, 550 feet north of East Carson Street, opposite South Twenty-seventh Street, Pittsburgh, Allegheny County, PA

  15. Plasmon-induced hot carriers in metallic nanoparticles.

    PubMed

    Manjavacas, Alejandro; Liu, Jun G; Kulkarni, Vikram; Nordlander, Peter

    2014-08-26

    Plasmon-induced hot carrier formation is attracting an increasing research interest due to its potential for applications in photocatalysis, photodetection and solar energy harvesting. However, despite very significant experimental effort, a comprehensive theoretical description of the hot carrier generation process is still missing. In this work we develop a theoretical model for the plasmon-induced hot carrier process and apply it to spherical silver nanoparticles and nanoshells. In this model, the conduction electrons of the metal are described as free particles in a finite spherical potential well, and the plasmon-induced hot carrier production is calculated using Fermi’s golden rule. We show that the inclusion of many-body interactions has only a minor influence on the results. Using the model we calculate the rate of hot carrier generation, finding that it closely follows the spectral profile of the plasmon. Our analysis reveals that particle size and hot carrier lifetime play a central role in determining both the production rate and the energy distribution of the hot carriers. Specifically, larger nanoparticle sizes and shorter lifetimes result in higher carrier production rates but smaller energies, and vice versa. We characterize the efficiency of the hot carrier generation process by introducing a figure of merit that measures the number of high energy carriers generated per plasmon. Furthermore, we analyze the spatial distribution and directionality of these excitations. The results presented here contribute to the basic understanding of plasmon-induced hot carrier generation and provide insight for optimization of the process.

  16. Liquid-metal atomization for hot working preforms

    NASA Technical Reports Server (NTRS)

    Grant, N. J.; Pelloux, R. M.

    1974-01-01

    Rapid quenching of a liquid metal by atomization or splat cooling overcomes the major limitation of most solidification processes, namely, the segregation of alloying elements, impurities, and constituent phases. The cooling rates of different atomizing processes are related to the dendrite arm spacings and to the microstructure of the atomized powders. The increased solubility limits and the formation of metastable compounds in splat-cooled alloys are discussed. Consolidation of the powders by hot isostatic compaction, hot extrusion, or hot forging and rolling processes yields billets with properties equivalent to or better than those of the wrought alloys. The application of this powder processing technology to high-performance alloys is reviewed.

  17. Canning Of Powdered Metal For Hot Isostatic Pressing

    NASA Technical Reports Server (NTRS)

    Juhas, John J.

    1989-01-01

    Quality of specimen enhanced by improved canning process. Method developed for canning specimens for hot isostatic pressing. Specimen placed inside refractory-metal ring, then sandwiched between two refractory-metal face sheets. Assembly placed inside die, then positioned in vacuum hot press. Heated to set temperature at prescribed vacuum to burn off all of binder in specimen. Advantages: powder-metallurgy composite totally purged of binder sealed in can in single operation, maintains size, shape, and uniformity of specimen. Weld region does not recrystallize, and little possibility of cracking.

  18. Metal vapor laser including hot electrodes and integral wick

    DOEpatents

    Ault, Earl R.; Alger, Terry W.

    1995-01-01

    A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube.

  19. Metal vapor laser including hot electrodes and integral wick

    DOEpatents

    Ault, E.R.; Alger, T.W.

    1995-03-07

    A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube. 5 figs.

  20. Upgrading and dephosphorization of Western Australian iron ore using reduction roasting by adding sodium carbonate

    NASA Astrophysics Data System (ADS)

    Zhu, De-qing; Chun, Tie-jun; Pan, Jian; Lu, Li-ming; He, Zhen

    2013-06-01

    The technology of direct reduction by adding sodium carbonate (Na2CO3) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals (SiO2 and Al2O3), forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product (metal iron powder) after briquetting can be used as the burden for steelmaking by an electric arc furnace to replace scrap steel.

  1. 12. Underside of Skew SpanHot Metal system on right, toward ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Underside of Skew Span-Hot Metal system on right, toward Rocker Bent. - Monongahela Connecting Railroad Company, Hot Metal Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

  2. Hot metal Si control at Kwangyang blast furnaces

    SciTech Connect

    Hur, N.S.; Cho, B.R.; Kim, G.Y.; Choi, J.S.; Kim, B.H.

    1995-12-01

    Studies of Si transfer in blast furnaces have shown that the Si level in pig iron is influenced more by the reaction of silicon oxide gas generation in the raceway than the chemical reaction between hot metal and slag at the drop zone. Specifications require a Si content of pig iron below 0.15% at the Kwangyang Works, but the use of soft coking coal in the blend for coke ovens, high pulverized coal injection rate into the blast furnace, and the application of lower grade iron ore has resulted in the need to develop methods to control Si in hot metal. In this paper, the results of in furnace Si control and the desiliconization skills at the casthouse floor are described.

  3. Amplification of hot electron flow by the surface plasmon effect on metal-insulator-metal nanodiodes.

    PubMed

    Lee, Changhwan; Nedrygailov, Ievgen I; Lee, Young Keun; Ahn, Changui; Lee, Hyosun; Jeon, Seokwoo; Park, Jeong Young

    2015-11-01

    Au-TiO2-Ti nanodiodes with a metal-insulator-metal structure were used to probe hot electron flows generated upon photon absorption. Hot electrons, generated when light is absorbed in the Au electrode of the nanodiode, can travel across the TiO2, leading to a photocurrent. Here, we demonstrate amplification of the hot electron flow by (1) localized surface plasmon resonance on plasmonic nanostructures fabricated by annealing the Au-TiO2-Ti nanodiodes, and (2) reducing the thickness of the TiO2. We show a correlation between changes in the morphology of the Au electrodes caused by annealing and amplification of the photocurrent. Based on the exponential dependence of the photocurrent on TiO2 thickness, the transport mechanism for the hot electrons across the nanodiodes is proposed. PMID:26451470

  4. Amplification of hot electron flow by the surface plasmon effect on metal-insulator-metal nanodiodes

    NASA Astrophysics Data System (ADS)

    Lee, Changhwan; Nedrygailov, Ievgen I.; Lee, Young Keun; Ahn, Changui; Lee, Hyosun; Jeon, Seokwoo; Park, Jeong Young

    2015-11-01

    Au-TiO2-Ti nanodiodes with a metal-insulator-metal structure were used to probe hot electron flows generated upon photon absorption. Hot electrons, generated when light is absorbed in the Au electrode of the nanodiode, can travel across the TiO2, leading to a photocurrent. Here, we demonstrate amplification of the hot electron flow by (1) localized surface plasmon resonance on plasmonic nanostructures fabricated by annealing the Au-TiO2-Ti nanodiodes, and (2) reducing the thickness of the TiO2. We show a correlation between changes in the morphology of the Au electrodes caused by annealing and amplification of the photocurrent. Based on the exponential dependence of the photocurrent on TiO2 thickness, the transport mechanism for the hot electrons across the nanodiodes is proposed.

  5. Inhibition of hot salt corrosion by metallic additives

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.

    1978-01-01

    The effectiveness of several potential fuel additives in reducing the effects of sodium sulfate-induced hot corrosion was evaluated in a cyclic Mach 0.3 burner rig. The potential inhibitors examined were salts of Al, Si, Cr, Fe, Zn, Mg, Ca, and Ba. The alloys tested were IN-100, U-700, IN-738, IN-792, Mar M-509, and 304 stainless steel. Each alloy was exposed for 100 cycles of 1 hour each at 900 C in combustion gases doped with the corrodant and inhibitor salts and the extent of attack was determined by measuring maximum metal thickness loss. The most effective and consistent inhibitor additive was Ba (NO3)2 which reduced the hot corrosion attack to nearly that of simple oxidation.

  6. Dependence of Temperature and Slag Composition on Dephosphorization at the First Deslagging in BOF Steelmaking Process

    NASA Astrophysics Data System (ADS)

    Zhou, Chao-gang; Li, Jing; Shi, Cheng-bin; Yu, Wen-tao; Zhang, Zhi-ming; Liu, Zhi-ming; Deng, Chang-fu

    2016-04-01

    Effects of temperature and slag composition on dephosphorization in a 120 ton top-bottom combined blown converter steelmaking process by double slag method were studied. The slag properties were determined by scanning electron microscope- energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD). The results show that the transition oxidation temperature between dephosphorization and decarbonization Tf is not the favorable temperature for the first deslagging. The optimum first deslagging temperature is confirmed to be approximately 1,673 K which is about 70 K higher than Tf. High melting temperatures phases (such as 3CaO·SiO2) in the slag with high basicity and MgO content are unfavorable to the dephosphorization. The optimum process condition for dephosphorization at the first deslagging in present work is approximately 1,673 K in temperature, 2.0 in slag basicity, 6 and 17 mass% in MgO and T.Fe content, 6 mass% ≤ MnO content.

  7. Metallic hot wire anemometer. [for high speed wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Lemos, F. R. (Inventor)

    1977-01-01

    A hot wire anemometer is described which has a body formed of heat resistant metal such as an alloy high in nickel content which supports a probe wire disposed in a V groove in the body. The V groove contains a high temperature ceramic adhesive that partially encompasses the downstream side of the probe wire. Mechanical and electrical connection to the probe wire is achieved through conductive support rods that are constructed of the same high temperature metal, insulation between the body and the conductor rods being provided by a coating of an oxide of the same material which coating is formed in situ. The oxide coating insulates the conductor rods from the body, mechanically fixes the conductors within the body, and maintains its integrity at elevated temperatures.

  8. Dephosphorization of High-Phosphorus Iron Ore Using Different Sources of Aspergillus niger Strains.

    PubMed

    Xiao, Chunqiao; Wu, Xiaoyan; Chi, Ruan

    2015-05-01

    High-phosphorus iron ore is traditionally dephosphorized by chemical process with inorganic acids. However, this process is not recommended nowadays because of its high cost and consequent environmental pollution. With the current tendency for development of a low-cost and eco-friendly process, dephosphorization of high-phosphorus iron ore through microbial process with three different sources of Aspergillus niger strains was studied in this study. Results show that the three strains of A. niger could grow well in the broth, and effectively remove phosphate from high-phosphorus iron ore during the experiments. Meanwhile, the total iron in the broth was also increased. Acidification of the broth seemed to be the major mechanism for the dephosphorization by these strains. High-pressure liquid chromatography analysis indicated that various organic acids were secreted in the broth, which caused a significant drop of the broth pH. Scanning electron microscopy of ore residues revealed that the high-phosphorus iron ore was obviously destroyed by the actions of these strains. Ore residues by energy-dispersive X-ray microanalysis and Fourier transform infrared spectroscopy indicated that the phosphate was obviously removed from the high-phosphorus iron ore. The optimization of the dephosphorization by these strains was also investigated, and the maximum percentages of phosphate removal were recorded at temperature 27-30 °C, initial pH 5.0-6.5, particle size 0.07-0.1 mm, and pulp density of 2-3% (w/v), respectively. The fungus A. niger was found to have good potential for the dephosphorization of high-phosphorus iron ore, and this microbial process seems to be economic and effective in the future industrial application.

  9. METAShield: Hot Metallic Aeroshell Concept for RLV/SOV

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J.; Poteet, Carl C.; Daryabeigi, Kamran; Nowak, Robert J.; Hsu, Su-Yuen; Schmidt, Irvin H.; Ku, Shih-Huei P.

    2003-01-01

    An innovative fuselage design approach that combines many desirable operational features with a simple and efficient structural approach is being developed by NASA. The approach, named METAShield for MEtallic TransAtmospheric Shield, utilizes lightly loaded, hot aeroshell structures surrounding integral propellant tanks that carry the primary structural loads. The aeroshells are designed to withstand the local pressure loads, transmitting them to the tanks with minimal restraint of thermal growth. No additional thermal protection system protects the METAShield, and a fibrous or multilayer insulation blanket, located in the space between the aeroshell and the tanks, serves as both high temperature and cryogenic insulation for the tanks. The concept is described in detail, and the performance and operational features are highlighted. Initial design results and analyses of the structural, thermal, and thermal-structural performance are described. Computational results evaluating resistance to hypervelocity impact damage, as well as some supporting aerothermal wind tunnel results. are also presented. Future development needs are summarized.

  10. Metal-induced decomposition of perchlorate in pressurized hot water.

    PubMed

    Hori, Hisao; Sakamoto, Takehiko; Tanabe, Takashi; Kasuya, Miu; Chino, Asako; Wu, Qian; Kannan, Kurunthachalam

    2012-10-01

    Decomposition of perchlorate (ClO(4)(-)) in pressurized hot water (PHW) was investigated. Although ClO(4)(-) demonstrated little reactivity in pure PHW up to 300°C, addition of zerovalent metals to the reaction system enhanced the decomposition of ClO(4)(-) to Cl(-) with an increasing order of activity of (no metal)≈Al < Cu < Zn < Ni < Fe: the addition of iron powder led to the most efficient decomposition of ClO(4)(-). When the iron powder was added to an aqueous ClO(4)(-) solution (104 μM) and the mixture was heated at 150°C, ClO(4)(-) concentration fell below 0.58 μM (58 μg L(-1), detection limit of ion chromatography) in 1 h, and Cl(-) was formed with the yield of 85% after 6 h. The decomposition was accompanied by transformation of the zerovalent iron to Fe(3)O(4). This method was successfully used in the decomposition of ClO(4)(-) in a water sample contaminated with this compound, following fireworks display at Albany, New York, USA.

  11. Metal-induced decomposition of perchlorate in pressurized hot water.

    PubMed

    Hori, Hisao; Sakamoto, Takehiko; Tanabe, Takashi; Kasuya, Miu; Chino, Asako; Wu, Qian; Kannan, Kurunthachalam

    2012-10-01

    Decomposition of perchlorate (ClO(4)(-)) in pressurized hot water (PHW) was investigated. Although ClO(4)(-) demonstrated little reactivity in pure PHW up to 300°C, addition of zerovalent metals to the reaction system enhanced the decomposition of ClO(4)(-) to Cl(-) with an increasing order of activity of (no metal)≈Al < Cu < Zn < Ni < Fe: the addition of iron powder led to the most efficient decomposition of ClO(4)(-). When the iron powder was added to an aqueous ClO(4)(-) solution (104 μM) and the mixture was heated at 150°C, ClO(4)(-) concentration fell below 0.58 μM (58 μg L(-1), detection limit of ion chromatography) in 1 h, and Cl(-) was formed with the yield of 85% after 6 h. The decomposition was accompanied by transformation of the zerovalent iron to Fe(3)O(4). This method was successfully used in the decomposition of ClO(4)(-) in a water sample contaminated with this compound, following fireworks display at Albany, New York, USA. PMID:22840541

  12. Ultrafast Hot Carrier Scattering and Generation from Surface Plasmons in Noble Metals

    NASA Astrophysics Data System (ADS)

    Bernardi, Marco; Mustafa, Jamal; Neaton, Jeffrey B.; Louie, Steven G.

    2015-03-01

    Non-equilibrium ``hot''carriers in materials are challenging to study experimentally as they thermalize at subpicosecond time and nanometer length scale. Recent experiments employed hot carriers generated by light absorption or surface plasmon annihilation in noble metals (e.g., Au and Ag) for catalysis and solar cells. The energy distribution and transport of the generated hot carriers play a key role in these experiments. We present ab initio calculations of the energy distribution of hot carriers generated by surface plasmons in noble metals, and the relaxation time and mean free path of the hot carriers along different crystal directions within 5 eV of the Fermi energy. Our calculations show the interplay of the noble metal s and d bands in determining the damping rate of the plasmon and the mean free path of the hot carriers. The trends we find as a function of surface plasmon momentum and frequency allow us to define optimal experimental conditions for hot carrier generation and extraction. Our approach combines density functional theory, GW, and electron-phonon calculations. Our work provides microscopic insight into hot carriers in noble metals, and their ultrafast dynamics in the presence of surface plasmons.

  13. Development and characterization of polymers-metallic hot embossing process for manufacturing metallic micro-parts

    NASA Astrophysics Data System (ADS)

    Sahli, M.; Millot, C.; Gelin, J.-C.; Barrière, T.

    2011-01-01

    In the recent years, hot embossing process becomes a promising process for the replication of polymer micro-structures associated to its manufacturing capability related to a relatively low component cost. This rising demand has prompted the development of various micro-manufacturing techniques in an attempt to get micro-parts in large batch. The paper investigates the way to get metallic micro-parts through the hot embossing process. The micro-manufacturing process consists in three stages. In the first one, the different metallic feedstocks with 50 to 60% powder loading in volume have been prepared with adapted polymers/powders formulations. In a second stage, an elastomeric master has been used to obtain micro-parts on a plastic loaded substrate with developed mixture based on polypropylene, paraffin wax and stearic acid. Finally, a thermal debinding stage in nitrogen atmosphere followed by a solid state pre-sintering stage has been applied, in order to eliminate the pores between powder particles in the debinded components. Then the porous components are agglomerated by solid state diffusion after heating to a temperature slightly lower than the melting temperature related to the material used in the process, to form an homogenous structure when full densification is achieved. The advantages of this approach include: rapid manufacturing of injection tools with high-quality, easy demoulding of metallic parts from the elastomeric moulds and great flexibility related to the choices of material. The paper describes all the processing stages and the way to characterize the geometrical, physical and mechanical properties of the resulting micro-parts.

  14. Plasmon-induced Hot Carriers in Metallic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Manjavacas, Alejandro; Kulkarni, Vikram; Nordlander, Peter; LANP Team

    2015-03-01

    Plasmon-induced hot carrier formation is attracting an increasing research interest due to its potential for applications in photocatalysis, photodetection and solar energy harvesting. Here we develop a theoretical model for the plasmon-induced hot carrier process and apply it to spherical silver nanoparticles and nanoshells. We show that the inclusion of many-body interactions has only a minor influence on the results. Using the model we calculate the rate of hot carrier generation, finding that it closely follows the spectral profile of the plasmon. Our analysis reveals that particle size and hot carrier lifetime play a central role in determining both the production rate and the energy distribution of the hot carriers. We characterize the efficiency of the hot carrier generation process by introducing a figure of merit that measures the number of high energy carriers generated per plasmon. Furthermore, we analyze the spatial distribution and directionality of these excitations. A. M. acknowledges financial support from the Welch foundation through the J. Evans Attwell-Welch Postdoctoral Fellowship Program of the Smalley Institute of Rice University (Grant No. L-C-004).

  15. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

    PubMed

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-23

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits.

  16. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure

    NASA Astrophysics Data System (ADS)

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-01

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits.

  17. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

    PubMed

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-23

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits. PMID:27533591

  18. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes.

    PubMed

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-29

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation. PMID:27168177

  19. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes.

    PubMed

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-29

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  20. Hot, Massive Stars in the Extremely Metal-Poor Galaxy, I Zw 18

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Malumuth, Eliot M.

    2010-01-01

    The extremely metal-poor galaxy I Zw 18, is the Rosetta Stone for understanding z=7-8 galaxies now being discovered by Hubb|e's Wide Field Camera 3 (HST/WFC3). Using HST/STIS images and recently obtained HST/COS ultraviolet spectra, we derive information about the hot, massive stars in this galaxy including stellar abundances, constraints on the stellar IMF and mass distribution of young clusters containing hot, massive stars.

  1. Electrical contact resistance degradation of a hot-switched simulated metal MEMS contact.

    SciTech Connect

    Dugger, Michael Thomas; Dickrell, Daniel John, III

    2005-03-01

    Electrical contact resistance testing was performed by hot-switching a simulated gold-platinum metal microelectromechanical systems contact. The experimental objective was to determine the sensitivity of the contact resistance degradation to current level and environment. The contact resistance increased sharply after 100 hot-switched cycles in air. Hot-switching at a reduced current and in nitrogen atmosphere curtailed contact resistance degradation by several orders of magnitude. The mechanism responsible for the resistance degradation was found to be arc-induced decomposition of adsorbed surface contaminants.

  2. High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, Clarence L.

    1993-01-01

    Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

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

    DOEpatents

    Hoenig, Clarence L.

    1994-01-01

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

  4. High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, C.L.

    1993-08-31

    Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1,800 C and 30 PSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

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

    DOEpatents

    Hoenig, C.L.

    1994-08-09

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

  6. Translation of nanoantenna hot spots by a metal-dielectric composite superlens

    NASA Astrophysics Data System (ADS)

    Liu, Zhengtong; Thoreson, Mark D.; Kildishev, Alexander V.; Shalaev, Vladimir M.

    2009-07-01

    We employ numerical simulations to show that highly localized, enhanced electromagnetic fields, also known as "hot spots," produced by a periodic array of silver nanoantennas can be spatially translated to the other side of a metal-dielectric composite superlens. The proposed translation of the hot spots enables surface-enhanced optical spectroscopy without the undesirable contact of molecules with metal, and thus it broadens and reinforces the potential applications of sensing based on field-enhanced fluorescence and surface-enhanced Raman scattering.

  7. Plant uptake and the leaching of metals during the hot EDDS-enhanced phytoextraction process.

    PubMed

    Luo, Chun-Ling; Shen, Zhen-Guo; Li, Xiang-Dong

    2007-01-01

    Using pot experiments, the effect of the application of the biodegradable chelating agent S,S-ethylenediaminedisuccinic acid (EDDS) in hot solutions at 90 degrees C on the uptake of Cu, Pb, Zn, and Cd by corn (Zea mays L. cv. Nongda No. 108) and beans (P vulgaris L. white bean), and the potential leaching of metals from soil, were studied. When EDDS was applied as a hot solution at the rate of 1 mmol kg(-1), the concentrations and total phytoextraction of metals in plant shoots exceeded or approximated those in the shoots of plants treated with normal EDDS at the rate of 5 mmol kg(-1). On the other hand, the leaching of Cu, Pb, Zn, and Cd after the application of the hot EDDS solution at the rate of 1 mmol kg(-1) was reduced by 46%, 21%, 57%, and 35% in comparison with that from the application of normal EDDS at 5 mmol kg(-1), respectively. For treatment with 1 mmol kg(-1) of EDDS, the leached metals decreased to the levels of the control group (that without EDDS amendment) 14 d after the application of EDDS. The soil amendment with biodegradable EDDS in hot solutions may provide a good alternative to chelate-enhanced phytoextraction in enhancing metal uptake by plants and limiting metals from leaching out of the soil.

  8. Modeling and FE Simulation of Quenchable High Strength Steels Sheet Metal Hot Forming Process

    NASA Astrophysics Data System (ADS)

    Liu, Hongsheng; Bao, Jun; Xing, Zhongwen; Zhang, Dejin; Song, Baoyu; Lei, Chengxi

    2011-08-01

    High strength steel (HSS) sheet metal hot forming process is investigated by means of numerical simulations. With regard to a reliable numerical process design, the knowledge of the thermal and thermo-mechanical properties is essential. In this article, tensile tests are performed to examine the flow stress of the material HSS 22MnB5 at different strains, strain rates, and temperatures. Constitutive model based on phenomenological approach is developed to describe the thermo-mechanical properties of the material 22MnB5 by fitting the experimental data. A 2D coupled thermo-mechanical finite element (FE) model is developed to simulate the HSS sheet metal hot forming process for U-channel part. The ABAQUS/explicit model is used conduct the hot forming stage simulations, and ABAQUS/implicit model is used for accurately predicting the springback which happens at the end of hot forming stage. Material modeling and FE numerical simulations are carried out to investigate the effect of the processing parameters on the hot forming process. The processing parameters have significant influence on the microstructure of U-channel part. The springback after hot forming stage is the main factor impairing the shape precision of hot-formed part. The mechanism of springback is advanced and verified through numerical simulations and tensile loading-unloading tests. Creep strain is found in the tensile loading-unloading test under isothermal condition and has a distinct effect on springback. According to the numerical and experimental results, it can be concluded that springback is mainly caused by different cooling rats and the nonhomogengeous shrink of material during hot forming process, the creep strain is the main factor influencing the amount of the springback.

  9. Hot gas desulfurization with sorbents containing mixed metal oxides

    SciTech Connect

    Akyurtlu, J.F.; Akyurtlu, A.

    1992-12-31

    Advanced power generation systems such as the integrated gasification combined cycle power generators and the molten carbonate fuel cells have stringent fuel gas desulfurization requirements and process economics dictates that this desulfurization be performed near the temperature of the gasification off-gas. The most advanced hot gas desulfurization technology today is based on the zinc ferrite sorbent which has several shortcomings such as zinc loss by evaporation, and incomplete regeneration due to sulfate formation. The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance.of sorbents prepared by the addition of various amounts of V{sub 2}0{sub 5} to the zinc ferrite sorbent is investigated. Preliminary experiments show that the sorbent containing about 4.8 mass % vanadium shows a superior desulfurization performance compared to zinc ferrite. Addition of vanadium suppresses residual sulfate formation and possibly zinc evaporation. significant quantities of elemental sulfur were observed after the regeneration of vanadium containing sorbents.

  10. Hot hydrogen testing of metallic turbo pump materials

    NASA Technical Reports Server (NTRS)

    Zee, Ralph; Chin, Bryan; Inamdar, Rohit

    1993-01-01

    The objectives of this investigation are to expose heat resistant alloys to hydrogen at elevated temperatures and to use various microstructural and analytical techniques to determine the chemical and rate process involved in degradation of these materials due to hydrogen environment. Inconel 718 and NASA-23 (wrought and cast) are candidate materials. The degradation of these materials in the presence of 1 to 5 atmospheric pressure of hydrogen from 450 C to 1100 C was examined. The hydrogen facility at Auburn University was used for this purpose. Control experiments were also conducted wherein the samples were exposed to vacuum so that a direct comparison of the results would separate the thermal contribution from the hydrogen effects. The samples were analyzed prior to and after exposure. A residual gas collection system was used to determine the gaseous species produced by any chemical reaction that may have occurred during the exposure. Analysis of this gas sample shows only the presence of H2 as expected. Analyses of the samples were conducted using optical microscopy, x-ray diffraction, scanning electron microscopy, and weight change. There appears to be no change in weight of the samples as a result of hydrogen exposure. In addition no visible change on the surface structure was detected. This indicates that the materials of interest do not have strong interaction with hot hydrogen. This is consistent with the microstructure results.

  11. Hot-carrier photocurrent effects at graphene-metal interfaces.

    PubMed

    Tielrooij, K J; Massicotte, M; Piatkowski, L; Woessner, A; Ma, Q; Jarillo-Herrero, P; van Hulst, N F; Koppens, F H L

    2015-04-29

    Photoexcitation of graphene leads to an interesting sequence of phenomena, some of which can be exploited in optoelectronic devices based on graphene. In particular, the efficient and ultrafast generation of an electron distribution with an elevated electron temperature and the concomitant generation of a photo-thermoelectric voltage at symmetry-breaking interfaces is of interest for photosensing and light harvesting. Here, we experimentally study the generated photocurrent at the graphene-metal interface, focusing on the time-resolved photocurrent, the effects of photon energy, Fermi energy and light polarization. We show that a single framework based on photo-thermoelectric photocurrent generation explains all experimental results.

  12. Development of Metallic Filters for Hot Gas Cleanup in Pressurized Fluidized Bed Combustion Applications

    SciTech Connect

    Anderson, I.E.; Gleeson, B.; Terpstra, R.L.

    2002-09-19

    Alternative alloys derived from the wide array of aerospace superalloys will be developed for hot gas filtration to improve on both ceramic filters and ''first-generation'' iron aluminide metallic filter materials. New high performance metallic filters should offer the benefits of non-brittle mechanical behavior at all temperatures, including ambient temperature, and improved resistance to thermal fatigue compared to ceramic filter elements, thus improving filter reliability. A new powder processing approach also will be established that results in lightweight metallic filters with high permeability and weldability for enhanced capability for filter system manufacturing.

  13. Large structural, thin-wall castings made of metals subject to hot tearing, and their fabrication

    NASA Technical Reports Server (NTRS)

    Smashey, Russell W. (Inventor)

    2001-01-01

    An article, such as a gas turbine engine mixer, is made by providing a mold structure defining a thin-walled, hollow article, and a base metal that is subject to hot tear cracking when cast in a generally equiaxed polycrystalline form, such as Rene' 108 and Mar-M247. The article is fabricated by introducing the molten base metal into the mold structure, and directionally solidifying the base metal in the mold structure to form a directionally oriented structure. The directionally oriented structure may be formed of a single grain or oriented multiple grains.

  14. Thermal Stress in HFEF Hot Cell Windows Due to an In-Cell Metal Fire

    DOE PAGESBeta

    Solbrig, Charles W.; Warmann, Stephen A.

    2016-01-01

    This work investigates an accident during the pyrochemical extraction of Uranium and Plutonium from PWR spent fuel in an argon atmosphere hot cell. In the accident, the heavy metals (U and Pu) being extracted are accidentally exposed to air from a leaky instrument penetration which goes through the cell walls. The extracted pin size pieces of U and Pu metal readily burn when exposed to air. Technicians perform the electrochemical extraction using manipulators through a 4 foot thick hot cell concrete wall which protects them from the radioactivity of the spent fuel. Four foot thick windows placed in the wallmore » allow the technicians to visually control the manipulators. These windows would be exposed to the heat of the metal fire. As a result, this analysis determines if the thermal stress caused by the fire would crack the windows and if the heat would degrade the window seals allowing radioactivity to escape from the cell.« less

  15. Thermal Stress in HFEF Hot Cell Windows Due to an In-Cell Metal Fire

    SciTech Connect

    Solbrig, Charles W.; Warmann, Stephen A.

    2016-01-01

    This work investigates an accident during the pyrochemical extraction of Uranium and Plutonium from PWR spent fuel in an argon atmosphere hot cell. In the accident, the heavy metals (U and Pu) being extracted are accidentally exposed to air from a leaky instrument penetration which goes through the cell walls. The extracted pin size pieces of U and Pu metal readily burn when exposed to air. Technicians perform the electrochemical extraction using manipulators through a 4 foot thick hot cell concrete wall which protects them from the radioactivity of the spent fuel. Four foot thick windows placed in the wall allow the technicians to visually control the manipulators. These windows would be exposed to the heat of the metal fire. As a result, this analysis determines if the thermal stress caused by the fire would crack the windows and if the heat would degrade the window seals allowing radioactivity to escape from the cell.

  16. Participation of hot electrons in oxygen adsorption and ethylene oxidation on metals

    SciTech Connect

    Maganyuk, A.P.; Starkovskii, N.I.; Yurchuk, S.Y.

    1995-04-01

    This paper reports the results obtained in the course of generating hot electrons by a device that is easier to fabricate and has more stability to chemically active compounds that a metal-insulator-metal systems: a Shottky-barrier diode having planar contact between a metal and a donor-doped semiconductor. In order to elucidate the potential effect of the promotion of chemical transformation by hot electrons, two specimens of different barrier heights were used: one a silicon-gold contact, the second a gallium arsenide film coated with layers of silver and a InNi alloy (3% Ni). These contacts were used to measure the current-voltage curve, the peak intensities curves which were proportional to the quantities of oxygen, water and carbon dioxide employed, and the peak intensities proportional to the formation rates of ethylene oxidation products.

  17. Hot Hydrogen Testing of Refractory Metals and Ceramics

    NASA Technical Reports Server (NTRS)

    Zee, Ralph; Chin, Bryan; Cohron, Jon

    1993-01-01

    The objective of this investigation is to develop a technique with which refractory metal carbide samples can be exposed to hydrogen containing gases at high temperatures, and to use various microstructural and analytical techniques to determine the chemical and rate processes involved in hydrogen degradation in these materials. Five types of carbides were examined including WC, NbC, HfC, ZrC, and TaC. The ceramics were purchased and were all monolithic in nature. The temperature range investigated was from 850 to 1600 C with a hydrogen pressure of one atmosphere. Control experiments, in vacuum, were also conducted for comparison so that the net effects due to hydrogen could be isolated. The samples were analyzed prior to and after exposure. Gas samples were collected in selected experiments and analyzed using gas chromography. Characterization of the resulting microstructure after exposure to hydrogen was conducted using optical microscopy, x-ray diffraction, scanning electron microscopy, and weight change. The ceramics were purchased and were all monolithic in nature. It was found that all samples lost weight after exposure, both in hydrogen and vacuum. Results from the microstructure analyses show that the degradation processes are different among the five types of ceramics involved. In addition, the apparent activation energy for the degradation process is a function of temperature even within the same material. This indicates that there are more than one mechanism involved in each material, and that the mechanisms are temperature dependent.

  18. Wavelength modulated SERS hot spot distribution in 1D nanostructures on metal film

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Zeng, Xiping; Liu, Ting; Zhang, Xuemei; Wei, Hua; Huang, Yingzhou; Liu, Anping; Wang, Shuxia; Wen, Weijia

    2016-10-01

    Surface plasmons confining strong electromagnetic fields near metal surfaces, well-known as hot spots, provide an extremely efficient platform for surface-enhanced Raman scattering (SERS). In this work, SERS spectra of probing molecules in a silver particle-wire 1D nanostructure on a thin gold film are investigated. The Raman features of SERS spectra collected at the particle-wire joints exhibit an obvious wavelength dependence phenomenon. This result is confirmed electromagnetic field simulation, revealing that hot spot distribution is sensitively influenced by the wavelength of incident light at the joints. Further studies indicate this wavelength dependence of hot spot distribution is immune to influence from the geometric shape of the particle or the angle between wire and particle, which improves fabrication tolerance. This technology may have promising applications in surface plasmon related fields, such as ultrasensors, solar energy and selective surface catalysis.

  19. Hot electron-induced reduction of small molecules on photorecycling metal surfaces

    NASA Astrophysics Data System (ADS)

    Xie, Wei; Schlücker, Sebastian

    2015-07-01

    Noble metals are important photocatalysts due to their ability to convert light into chemical energy. Hot electrons, generated via the non-radiative decay of localized surface plasmons, can be transferred to reactants on the metal surface. Unfortunately, the number of hot electrons per molecule is limited due to charge-carrier recombination. In addition to the reduction half-reaction with hot electrons, also the corresponding oxidation counter-half-reaction must take place since otherwise the overall redox reaction cannot proceed. Here we report on the conceptual importance of promoting the oxidation counter-half-reaction in plasmon-mediated catalysis by photorecycling in order to overcome this general limitation. A six-electron photocatalytic reaction occurs even in the absence of conventional chemical reducing agents due to the photoinduced recycling of Ag atoms from hot holes in the oxidation half-reaction. This concept of multi-electron, counter-half-reaction-promoted photocatalysis provides exciting new opportunities for driving efficient light-to-energy conversion processes.

  20. High density hexagonal boron nitride prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, Clarence L.

    1992-01-01

    Boron nitride powder with less than or equal to the oxygen content of starting powder (down to 0.5% or less) is hot isostatically pressed in a refractory metal container to produce hexagonal boron nitride with a bulk density greater than 2.0 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.21 g/cc. Complex shapes can be made.

  1. A New Process for Hot Metal Production at Low Fuel Rate - Phase 1 Feasibility Study

    SciTech Connect

    Dr. Wei-Kao Lu

    2006-02-01

    The project is part of the continuing effort by the North American steel industry to develop a coal-based, cokeless process for hot metal production. The objective of Phase 1 is to determine the feasibility of designing and constructing a pilot scale facility with the capacity of 42,000 mtpy of direct reduced iron (DRI) with 95% metallization. The primary effort is performed by Bricmont, Inc., an international engineering firm, under the supervision of McMaster University. The study focused on the Paired Straight Hearth furnace concept developed previously by McMaster University, The American Iron and Steel Institute and the US Department of Energy.

  2. Surface plasmon assisted hot electron collection in wafer-scale metallic-semiconductor photonic crystals.

    PubMed

    Chou, Jeffrey B; Li, Xin-Hao; Wang, Yu; Fenning, David P; Elfaer, Asmaa; Viegas, Jaime; Jouiad, Mustapha; Shao-Horn, Yang; Kim, Sang-Gook

    2016-09-01

    Plasmon assisted photoelectric hot electron collection in a metal-semiconductor junction can allow for sub-bandgap optical to electrical energy conversion. Here we report hot electron collection by wafer-scale Au/TiO2 metallic-semiconductor photonic crystals (MSPhC), with a broadband photoresponse below the bandgap of TiO2. Multiple absorption modes supported by the 2D nano-cavity structure of the MSPhC extend the photon-metal interaction time and fulfill a broadband light absorption. The surface plasmon absorption mode provides access to enhanced electric field oscillation and hot electron generation at the interface between Au and TiO2. A broadband sub-bandgap photoresponse centered at 590 nm was achieved due to surface plasmon absorption. Gold nanorods were deposited on the surface of MSPhC to study localized surface plasmon (LSP) mode absorption and subsequent injection to the TiO2 catalyst at different wavelengths. Applications of these results could lead to low-cost and robust photo-electrochemical applications such as more efficient solar water splitting.

  3. Behavior of fluxed lime iron oxide pellets in hot metal bath during melting and refining

    NASA Astrophysics Data System (ADS)

    Pal, J.; Ghorai, S.; Goswami, M. C.; Ghosh, D.; Bandyopadhyay, D.; Ghosh, S.

    2013-04-01

    Lump lime as a flux material in a basic oxygen furnace (BOF) often creates problems in operation due to its high melting point, poor dissolution property, hygroscopic nature, and fines generation tendency. To alleviate these problems, fluxed lime iron oxide pellets (FLIP) containing 30% CaO were developed in this study using waste iron oxide fines and lime. The suitable handling strengths of the pellet (crushing strength: 300 N; drop strength: 130 times) of FLIP were developed by treating with CO2 or industrial waste gas at room temperature, while no separate binders were used. When the pellet was added into hot metal bath (carbon-containing molten iron), it was decomposed, melted, and transformed to produce low melting oxidizing slag, because it is a combination of main CaO and Fe2O3. This slag is suitable for facilitating P and C removal in refining. Furthermore, the pellet enhances waste utilization and use of CO2 in waste gas. In this article, emphasis is given on studying the behavior of these pellets in hot metal bath during melting and refining along with thermodynamics and kinetics analysis. The observed behaviors of the pellet in hot metal bath confirm that it is suitable and beneficial for use in BOF and replaces lump lime.

  4. Surface plasmon assisted hot electron collection in wafer-scale metallic-semiconductor photonic crystals.

    PubMed

    Chou, Jeffrey B; Li, Xin-Hao; Wang, Yu; Fenning, David P; Elfaer, Asmaa; Viegas, Jaime; Jouiad, Mustapha; Shao-Horn, Yang; Kim, Sang-Gook

    2016-09-01

    Plasmon assisted photoelectric hot electron collection in a metal-semiconductor junction can allow for sub-bandgap optical to electrical energy conversion. Here we report hot electron collection by wafer-scale Au/TiO2 metallic-semiconductor photonic crystals (MSPhC), with a broadband photoresponse below the bandgap of TiO2. Multiple absorption modes supported by the 2D nano-cavity structure of the MSPhC extend the photon-metal interaction time and fulfill a broadband light absorption. The surface plasmon absorption mode provides access to enhanced electric field oscillation and hot electron generation at the interface between Au and TiO2. A broadband sub-bandgap photoresponse centered at 590 nm was achieved due to surface plasmon absorption. Gold nanorods were deposited on the surface of MSPhC to study localized surface plasmon (LSP) mode absorption and subsequent injection to the TiO2 catalyst at different wavelengths. Applications of these results could lead to low-cost and robust photo-electrochemical applications such as more efficient solar water splitting. PMID:27607726

  5. Ab initio phonon coupling and optical response of hot electrons in plasmonic metals

    NASA Astrophysics Data System (ADS)

    Brown, Ana M.; Sundararaman, Ravishankar; Narang, Prineha; Goddard, William A.; Atwater, Harry A.

    2016-08-01

    Ultrafast laser measurements probe the nonequilibrium dynamics of excited electrons in metals with increasing temporal resolution. Electronic structure calculations can provide a detailed microscopic understanding of hot electron dynamics, but a parameter-free description of pump-probe measurements has not yet been possible, despite intensive research, because of the phenomenological treatment of electron-phonon interactions. We present ab initio predictions of the electron-temperature dependent heat capacities and electron-phonon coupling coefficients of plasmonic metals. We find substantial differences from free-electron and semiempirical estimates, especially in noble metals above transient electron temperatures of 2000 K, because of the previously neglected strong dependence of electron-phonon matrix elements on electron energy. We also present first-principles calculations of the electron-temperature dependent dielectric response of hot electrons in plasmonic metals, including direct interband and phonon-assisted intraband transitions, facilitating complete theoretical predictions of the time-resolved optical probe signatures in ultrafast laser experiments.

  6. Fabrication and optical characterization of the normal metal hot-electron microbolometer with Andreev mirrors

    NASA Astrophysics Data System (ADS)

    Sandgren, D.; Chouvaev, D.; Tarasov, M.; Kuzmin, L.

    2002-08-01

    The normal metal hot-electron microbolometer (NHEB) is a direct detector for mm and sub-mm wavelengths. Theoretical estimations indicate that such a device should be able to achieve a sensitivity of around 10 -17 W/(Hz) 1/2 at 0.3 K and a time constant less than 1 μs. The temperature of the electron gas is monitored using superconductor-insulator-normal metal (SIN/NIS) tunnel junctions. We have fabricated such an NHEB where the normal metal strip is coupled to a double slot antenna for optical qualification (normal metal strip size (5.6×0.25×0.03) μm 3). The antenna is designed for 300 GHz and has an impedance of 30 Ω at the center frequency. The actual optical responsitivity and the response time of our NHEB has been measured at 0.5 K using a hot/cold load (black body radiation at room temperature and at liquid nitrogen temperature). DC-current measurements performed on other samples earlier indicate that our NHEB can achieve an electrical noise equivalent power (NEP) of at least 3×10 -16 W/(Hz) 1/2. We conclude that the optical responsitivity value obtained in the measurement is consistent with the electrical NEP value at the same temperature and in agreement with the estimated efficiency of the quasioptical coupling.

  7. Hot spots in different metal nanostructures for plasmon-enhanced Raman spectroscopy.

    PubMed

    Wei, Hong; Xu, Hongxing

    2013-11-21

    Noble metal nanostructures are able to concentrate light into small volumes, which enhances greatly the local electromagnetic (EM) field near the metal nanostructures. The areas with greatly enhanced EM field become "hot spots" for surface-enhanced Raman spectroscopy (SERS), which utilizes the field enhancement properties of metal nanostructures to amplify the usually weak Raman scattering signals. The preparation of metal nanostructures with superior SERS performances is one of the main topics in the SERS field and is important for the applications of SERS in sensing and analysis. In this feature article, we review several different kinds of metal structures for SERS, including coupled metal nanostructures, nanostructure arrays, nano/micro structures with textured surfaces and graphene-mediated SERS substrates. Tip-enhanced Raman spectroscopy (TERS) using the metal tip of the scanning tunneling microscope is also discussed. Besides the intensity enhancement in SERS and TERS, some less studied aspects are highlighted; for example, the remote excitation technique, tuning the nanogap of gold nanorod dimers through strain control on an elastomeric substrate, manipulating Raman emission polarization using asymmetric nanoantennas, and investigating plasmon-enhanced chemical reactions by TERS. PMID:24113688

  8. Solar energy conversion via hot electron internal photoemission in metallic nanostructures: Efficiency estimates

    SciTech Connect

    Leenheer, Andrew J.; Narang, Prineha; Atwater, Harry A.; Lewis, Nathan S.

    2014-04-07

    Collection of hot electrons generated by the efficient absorption of light in metallic nanostructures, in contact with semiconductor substrates can provide a basis for the construction of solar energy-conversion devices. Herein, we evaluate theoretically the energy-conversion efficiency of systems that rely on internal photoemission processes at metal-semiconductor Schottky-barrier diodes. In this theory, the current-voltage characteristics are given by the internal photoemission yield as well as by the thermionic dark current over a varied-energy barrier height. The Fowler model, in all cases, predicts solar energy-conversion efficiencies of <1% for such systems. However, relaxation of the assumptions regarding constraints on the escape cone and momentum conservation at the interface yields solar energy-conversion efficiencies as high as 1%–10%, under some assumed (albeit optimistic) operating conditions. Under these conditions, the energy-conversion efficiency is mainly limited by the thermionic dark current, the distribution of hot electron energies, and hot-electron momentum considerations.

  9. Theoretical analysis of hot electron injection from metallic nanotubes into a semiconductor interface.

    PubMed

    Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P

    2016-07-21

    Metallic nanostructures under optical illumination can generate a non-equilibrium high-energy electron gas (also known as hot electrons) capable of being injected into neighbouring media over a potential barrier at particle boundaries. The nature of this process is highly nanoparticle shape and size dependent. Here, we have derived an analytical expression for the frequency dependent rate of injection of these energetic electrons from a metallic nanotube into a semiconductor layer in contact with its inner boundary. In our derivation, we have considered the quantum mechanical motion of the electron gas confined by the particle boundaries in determining the electron energy spectrum and wave functions. We present a comprehensive theoretical analysis of how different geometric parameters such as the outer to inner radius ratio, length and thickness of a nanotube and illumination frequency affect the hot electron injection and internal quantum efficiency of the nanotube. We reveal that longer nanotubes with thin shells and high inner to outer radius ratios show better performance at visible and infrared frequencies. Our derivations and results provide the much needed theoretical insight for optimization of thin nanotubes for different hot electron based applications. PMID:27332556

  10. Theory and computation of hot carriers generated by surface plasmon polaritons in noble metals

    NASA Astrophysics Data System (ADS)

    Bernardi, Marco; Mustafa, Jamal; Neaton, Jeffrey B.; Louie, Steven G.

    2015-06-01

    Hot carriers (HC) generated by surface plasmon polaritons (SPPs) in noble metals are promising for application in optoelectronics, plasmonics and renewable energy. However, existing models fail to explain key quantitative details of SPP-to-HC conversion experiments. Here we develop a quantum mechanical framework and apply first-principles calculations to study the energy distribution and scattering processes of HCs generated by SPPs in Au and Ag. We find that the relative positions of the s and d bands of noble metals regulate the energy distribution and mean free path of the HCs, and that the electron-phonon interaction controls HC energy loss and transport. Our results prescribe optimal conditions for HC generation and extraction, and invalidate previously employed free-electron-like models. Our work combines density functional theory, GW and electron-phonon calculations to provide microscopic insight into HC generation and ultrafast dynamics in noble metals.

  11. Theory and computation of hot carriers generated by surface plasmon polaritons in noble metals.

    PubMed

    Bernardi, Marco; Mustafa, Jamal; Neaton, Jeffrey B; Louie, Steven G

    2015-01-01

    Hot carriers (HC) generated by surface plasmon polaritons (SPPs) in noble metals are promising for application in optoelectronics, plasmonics and renewable energy. However, existing models fail to explain key quantitative details of SPP-to-HC conversion experiments. Here we develop a quantum mechanical framework and apply first-principles calculations to study the energy distribution and scattering processes of HCs generated by SPPs in Au and Ag. We find that the relative positions of the s and d bands of noble metals regulate the energy distribution and mean free path of the HCs, and that the electron-phonon interaction controls HC energy loss and transport. Our results prescribe optimal conditions for HC generation and extraction, and invalidate previously employed free-electron-like models. Our work combines density functional theory, GW and electron-phonon calculations to provide microscopic insight into HC generation and ultrafast dynamics in noble metals. PMID:26033445

  12. Theory and computation of hot carriers generated by surface plasmon polaritons in noble metals

    PubMed Central

    Bernardi, Marco; Mustafa, Jamal; Neaton, Jeffrey B.; Louie, Steven G.

    2015-01-01

    Hot carriers (HC) generated by surface plasmon polaritons (SPPs) in noble metals are promising for application in optoelectronics, plasmonics and renewable energy. However, existing models fail to explain key quantitative details of SPP-to-HC conversion experiments. Here we develop a quantum mechanical framework and apply first-principles calculations to study the energy distribution and scattering processes of HCs generated by SPPs in Au and Ag. We find that the relative positions of the s and d bands of noble metals regulate the energy distribution and mean free path of the HCs, and that the electron–phonon interaction controls HC energy loss and transport. Our results prescribe optimal conditions for HC generation and extraction, and invalidate previously employed free-electron-like models. Our work combines density functional theory, GW and electron–phonon calculations to provide microscopic insight into HC generation and ultrafast dynamics in noble metals. PMID:26033445

  13. Indirect Band Gap Emission by Hot Electron Injection in Metal/MoS2 and Metal/WSe2 Heterojunctions

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Ezhilarasu, Goutham; Chatzakis, Ioannis; Dhall, Rohan; Chen, Chun-Chung; Cronin, Stephen

    Transition metal dichalcogenides (TMDCs), such as MoS2 and WSe2, are free of dangling bonds, therefore make more `ideal' Schottky junctions than bulk semiconductors, which produce recombination centers at the interface with metals, inhibiting charge transfer. Here, we observe a more than 10X enhancement in the indirect band gap PL of TMDCs deposited on various metals, while the direct band gap emission remains unchanged. We believe the main mechanism of light emission arises from photoexcited hot electrons in the metal that are injected into the conduction band of MoS2 and WSe2, and subsequently recombine radiatively with minority holes. Since the conduction band at the K-point is 0.5eV higher than at the Σ-point, a lower Schottky barrier of the Σ-point band makes electron injection more favorable. Also, the Σ band consists of the sulfur pz orbital, which overlaps more significantly with the electron wavefunctions in the metal. This enhancement only occurs for thick flakes, and is absent in monolayer and few-layer flakes. Here, the flake thickness must exceed the depletion width of the Schottky junction, in order for efficient radiative recombination to occur in the TMDC. The intensity of this indirect peak decreases at low temperatures. Reference: DOI: 10.1021/acs.nanolett.5b00885

  14. Magnetotransport of multiple-band nearly antiferromagnetic metals due to hot-spot scattering

    NASA Astrophysics Data System (ADS)

    Koshelev, A. E.

    2016-09-01

    Multiple-band electronic structure and proximity to antiferromagnetic (AF) instability are the key properties of iron-based superconductors. We explore the influence of scattering by the AF spin fluctuations on transport of multiple-band metals above the magnetic transition. A salient feature of scattering on the AF fluctuations is that it is strongly enhanced at the Fermi surface locations where the nesting is perfect ("hot spots" or "hot lines"). We review derivation of the collision integral for the Boltzmann equation due to AF-fluctuations scattering. In the paramagnetic state, the enhanced scattering rate near the hot lines leads to anomalous behavior of electronic transport in magnetic field. We explore this behavior by analytically solving the Boltzmann transport equation with approximate transition rates. This approach accounts for return scattering events and is more accurate than the relaxation-time approximation. The magnetic-field dependences are characterized by two very different field scales: the lower scale is set by the hot-spot width and the higher scale is set by the total scattering amplitude. A conventional magnetotransport behavior is limited to magnetic fields below the lower scale. In the wide range in-between these two scales, the longitudinal conductivity has linear dependence on the magnetic field and the Hall conductivity has quadratic dependence. The linear dependence of the diagonal component reflects growth of the Fermi-surface area affected by the hot spots proportional to the magnetic field. We discuss applicability of this theoretical framework for describing of anomalous magnetotransport properties in different iron pnictides and chalcogenides in the paramagnetic state.

  15. Strong and highly asymmetrical optical absorption in conformal metal-semiconductor-metal grating system for plasmonic hot-electron photodetection application

    PubMed Central

    Wu, Kai; Zhan, Yaohui; Zhang, Cheng; Wu, Shaolong; Li, Xiaofeng

    2015-01-01

    We propose an architecture of conformal metal-semiconductor-metal (MSM) device for hot-electron photodetection by asymmetrical alignment of the semiconductor barrier relative to the Fermi level of metals and strong energy localization through plasmonic resonances. Compared with the conventional grating design, the multi-layered grating system under conformal configuration is demonstrated to possess both optical and electrical advantages for high-sensitivity hot-electron photodetection. Finite-element simulation reveals that a strong and highly asymmetrical optical absorption (top metal absorption >99%) can be realized under such a conformal arrangement. An analytical probability-based electrical simulation verifies the strong unidirectional photocurrent, by taking advantage of the extremely high net absorption and a low metal/semiconductor barrier height, and predicts that the corresponding photoresponsivity can be ~3 times of that based on the conventional grating design in metal-insulator-metal (MIM) configuration. PMID:26387836

  16. Processes of conversion of a hot metal particle into aerogel through clusters

    SciTech Connect

    Smirnov, B. M.

    2015-10-15

    Processes are considered for conversion into a fractal structure of a hot metal micron-size particle that is located in a buffer gas or a gas flow and is heated by an external electric or electromagnetic source or by a plasma. The parameter of this heating is the particle temperature, which is the same in the entire particle volume because of its small size and high conductivity. Three processes determine the particle heat balance: particle radiation, evaporation of metal atoms from the particle surface, and heat transport to the surrounding gas due to its thermal conductivity. The particle heat balance is analyzed based on these processes, which are analogous to those for bulk metals with the small particle size, and its high temperature taken into account. Outside the particle, where the gas temperature is lower than on its surface, the formed metal vapor in a buffer gas flow is converted into clusters. Clusters grow as a result of coagulation until they become liquid, and then clusters form fractal aggregates if they are removed form the gas flow. Subsequently, associations of fractal aggregates join into a fractal structure. The rate of this process increases in medium electric fields, and the formed fractal structure has features of aerogels and fractal fibers. As a result of a chain of the above processes, a porous metal film may be manufactured for use as a filter or catalyst for gas flows.

  17. Processes of conversion of a hot metal particle into aerogel through clusters

    NASA Astrophysics Data System (ADS)

    Smirnov, B. M.

    2015-10-01

    Processes are considered for conversion into a fractal structure of a hot metal micron-size particle that is located in a buffer gas or a gas flow and is heated by an external electric or electromagnetic source or by a plasma. The parameter of this heating is the particle temperature, which is the same in the entire particle volume because of its small size and high conductivity. Three processes determine the particle heat balance: particle radiation, evaporation of metal atoms from the particle surface, and heat transport to the surrounding gas due to its thermal conductivity. The particle heat balance is analyzed based on these processes, which are analogous to those for bulk metals with the small particle size, and its high temperature taken into account. Outside the particle, where the gas temperature is lower than on its surface, the formed metal vapor in a buffer gas flow is converted into clusters. Clusters grow as a result of coagulation until they become liquid, and then clusters form fractal aggregates if they are removed form the gas flow. Subsequently, associations of fractal aggregates join into a fractal structure. The rate of this process increases in medium electric fields, and the formed fractal structure has features of aerogels and fractal fibers. As a result of a chain of the above processes, a porous metal film may be manufactured for use as a filter or catalyst for gas flows.

  18. Mobility of heavy metals from soil into hot pepper fruits: a field study.

    PubMed

    Antonious, G F; Kochhar, T S

    2009-01-01

    Capsaicin and dihydrocapsaicin contribute to pungency as well as having health-promoting properties, in peppers. Twenty-three genotypes (four spp.) of hot pepper from the USDA germplasm collection were grown in the field to identify accessions having increased concentrations of these two compounds and determine the concentrations of heavy metals, in mature fruits. Concentrations and relative proportions of capsaicin, dihydrocapsaicin, and seven heavy metals varied between and within pepper species. Plant Introduction 547069 (C. annuum) contained the greatest concentrations of the two pungent compounds. Fruits of PI-439381 and PI-267729 (C. baccatum) accumulated the greatest concentrations of Pb, while PI-246331 (C. annuum) accumulated the greatest concentration of Cd among accessions tested.

  19. Analysis of Operational Parameters Affecting the Sulfur Content in Hot Metal of the COREX Process

    NASA Astrophysics Data System (ADS)

    Wu, Shengli; Wang, Laixin; Kou, Mingyin; Wang, Yujue; Zhang, Jiacong

    2016-10-01

    The COREX process, which has obvious advantages in environment protection, still has some disadvantages. It has a higher sulfur content in hot metal (HM) than the blast furnace has. In the present work, the distribution and transfer of sulfur in the COREX have been analyzed and several operational parameters related to the sulfur content in HM ([pct S]) have been obtained. Based on this, the effects of the coal rate, slag ratio, temperature of HM, melting rate, binary basicity (R 2), the ratio of MgO/Al2O3, utilization of reducing gas, top gas consumption per ton burden solid, metallization rate, oxidation degree of reducing gas, and coal and DRI distribution index on the sulfur content in HM are investigated. What's more, a linear model has been developed and subsequently used for predicting and controlling the S content in HM of the COREX process.

  20. Photoelectric energy conversion of plasmon-generated hot carriers in metal-insulator-semiconductor structures.

    PubMed

    García de Arquer, F Pelayo; Mihi, Agustín; Kufer, Dominik; Konstantatos, Gerasimos

    2013-04-23

    Plasmonic excitation in metals has received great attention for light localization and control of light-matter interactions at the nanoscale with a plethora of applications in absorption enhancement, surface-enhanced Raman scattering, or biosensing. Electrically active plasmonic devices, which had remained underexplored, have recently become a growing field of interest. In this report we introduce a metal-insulator-semiconductor heterostructure for plasmo-electric energy conversion, a novel architecture to harvest hot-electrons derived from plasmonic excitations. We demonstrate external quantum efficiency (EQE) of 4% at 460 nm using a Ag nanostructured electrode and EQE of 1.3% at 550 nm employing a Au nanostructured electrode. The insulator interfacial layer has been found to play a crucial role in interface passivation, a requisite in photovoltaic applications to achieving both high open-circuit voltages (0.5 V) and fill-factors (0.5), but its introduction simultaneously modifies hot-electron injection and transport. We investigate the influence passivation has on these processes for different material configurations, and characterize different types of transport depending on the initial plasmon energy band, reporting power conversion efficiencies of 0.03% for nanopatterned silver electrodes. PMID:23495769

  1. 3D reconstruction of hot metallic surfaces for industrial part characterization

    NASA Astrophysics Data System (ADS)

    Bokhabrine, Youssef; Lew Yan Voon, Lew F. C.; Seulin, Ralph; Gorria, Patrick; Gomez, Miguel; Jobard, Daniel

    2009-02-01

    During industrial forging of big hot metallic shells, it is necessary to regularly measure the dimensions of the parts, especially the inner and outer diameters and the thickness of the walls, in order to decide when to stop the forging process. The inner and outer diameters of the shells range from 4 to 6 meters and to measure them a large ruler is placed horizontally at the end of the shell. Two blacksmiths standing on each side of the ruler at about ten meters from it visually reads the graduations on the ruler in order to determine the inner and outer diameters from which the thickness of the wall is determined. This operation is carried out several times during a forging process and it is very risky for the blacksmiths due to the high temperature of the shell when the measurement is done. Also, it is error prone and the result is rather inaccurate. In order to improve the working conditions, for the safety of the blacksmiths, and for a faster and more accurate measurement, a system based on two commercially available Time Of Flight (TOF) laser scanners for the measurement of cylindrical shell diameters during the forging process has been developed. The advantages of using laser scanners are that they can be placed very far from the hot shell, more than 15 meters, while at the same time giving an accurate point cloud from which 3D views of the shell can be reconstructed and diameter measurements done. Moreover, better dimensional measurement accuracy is achieved in less time with the laser system than with the conventional method using a large ruler. The system has been successfully used to measure the diameter of cold and hot cylindrical metallic shells.

  2. Investigation of surface topography effects on metal flow under lubricated hot compression of aluminum

    NASA Astrophysics Data System (ADS)

    Kurk, Justin Irvin

    An investigation was conducted to study the effects of die surface topography, specifically surface roughness and lay, on metal flow and the friction factor under lubricated hot compression. 6061-T6 aluminum rings and square bar stock specimens were compressed on H-13 tool steel platens machined with a unidirectional lay pattern to six different roughnesses between a R 0 10 and 240 muin. A lab based hydraulic press mounted with an experimental die set was used for all testing. Repeated trials were conducted using high temperature vegetable oil and boron nitride lubricants. Metal flow was quantified as a function of surface roughness, lay orientation, and die temperature. Approximate plane strain cigar test specimens were compressed at platen temperatures of 300 °F and 400 °F and at orientations of 0°, 45°, and 90° between the longitudinal axis and unidirectional platen surface lay. The friction factor was assessed using the ring compression test under varying platen roughness conditions and die temperatures between 250 °F and 400 °F. Results indicate metal flow is optimized at low platen roughnesses and orientations parallel to the surface lay of the platen. Die temperature was not found to influence metal flow within the temperature range investigated. The friction factor was observed to be minimized at lower die temperatures and platen roughnesses.

  3. EFFECT OF METALLICITY ON X-RAY EMISSION FROM THE WARM-HOT INTERGALACTIC MEDIUM

    SciTech Connect

    Ursino, E.; Galeazzi, M.; Roncarelli, M.

    2010-09-20

    Hydrodynamic simulations predict that a significant fraction of the gas in the current universe is in the form of high temperature, highly ionized plasma emitting and absorbing primarily in the soft X-ray and UV bands, dubbed the warm-hot intergalactic medium (WHIM). Its signature should be observable in redshifted emission and absorption lines from highly ionized elements. To determine the expected WHIM emission in the soft X-ray band we used the output of a large scale smoothed particle hydrodynamic simulation to generate images and spectra with angular resolution of 14'' and energy resolution of 1 eV. The current biggest limit of any hydrodynamic simulation in predicting the X-ray emission comes from metal diffusion. In our investigation, by using four different models for the WHIM metallicity we have found a strong dependence of the emission on the model used, with differences up to almost an order of magnitude. For each model, we have investigated the redshift distribution and angular scale of the emission, confirming that most photons come from redshift z < 1.2 and that the emission has a typical angular scale of less than a few arcminutes. We also compared our simulations with the few currently available observations and found that, within the variation of the metallicity models, our predictions are in good agreement with current constraints on the WHIM emission, and at this time the weak experimental constraints on the WHIM emission are not sufficient to exclude any of the models used.

  4. Nonequilibrium theory of a hot-electron bolometer with normal metal-insulator-superconductor tunnel junction

    SciTech Connect

    Golubev, Dmitri; Kuzmin, Leonid

    2001-06-01

    The operation of the hot-electron bolometer with normal metal-insulator-superconductor (NIS) tunnel junction as a temperature sensor is analyzed theoretically. The responsivity and the noise equivalent power (NEP) of the bolometer are obtained numerically for typical experimental parameters. Relatively simple approximate analytical expressions for these values are derived. The time constant of the device is also found. We demonstrate that the effect of the electron cooling by the NIS junction, which serves as a thermometer, can improve the sensitivity. This effect is also useful in the presence of the finite background power load. We discuss the effect of the correlation of the shot noise and the heat flow noise in the NIS junction. {copyright} 2001 American Institute of Physics.

  5. Strength and toughness of ceramic-metal composites prepared by reactive hot pressing

    SciTech Connect

    ELLERBY,DONALD T.; LOEHMAN,RONALD E.; FAHRENHOLTZ,WILLIAM G.

    2000-03-10

    Metal-reinforced Al{sub 2}0{sub 3}-matrix composites were prepared using reactive hot pressing. The volume fraction of the reinforcing phase was controlled by the stoichiometry of the particular displacement reaction used. Dense Al{sub 2}0{sub 3}-Ni and Al{sub 2}O{sub 3}-Nb composites were fabricated using this technique. The best combination of strength, 610 MPa, and toughness, 12 MPam{sup 1/2}, was found for the Al{sub 2}O{sub 3}-Ni composites. Indentation cracks and fracture surfaces showed evidence of ductile deformation of the Ni phase. The Al{sub 2}O{sub 3}-Nb composites had high strength, but the toughness was lower than expected due to the poor bonding between the Nb and A1{sub 2}0{sub 3}phases.

  6. KEPLER-6b: A TRANSITING HOT JUPITER ORBITING A METAL-RICH STAR

    SciTech Connect

    Dunham, Edward W.; Borucki, William J.; Koch, David G.; Lissauer, Jack J.; Batalha, Natalie M.; Buchhave, Lars A.; Furesz, Gabor; Geary, John C.; Latham, David W.; Brown, Timothy M.; Caldwell, Douglas A.; Jenkins, Jon M.; Cochran, William D.; Endl, Michael; Fischer, Debra; Gautier, Thomas N.; Gould, Alan; Howell, Steve B.; Kjeldsen, Hans

    2010-04-20

    We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a star with unusually high metallicity, [Fe/H]= +0.34{+-}0.04. The planet's mass is about 2/3 that of Jupiter, M {sub P} = 0.67 M {sub J}, and the radius is 30% larger than that of Jupiter, R {sub P} = 1.32 R {sub J}, resulting in a density of {rho}{sub P} = 0.35 g cm{sup -3}, a fairly typical value for such a planet. The orbital period is P = 3.235 days. The host star is both more massive than the Sun, M {sub *} = 1.21 M {sub sun}, and larger than the Sun, R {sub *} = 1.39 R {sub sun}.

  7. Applications of "Hot" and "Cold" Bis(thiosemicarbazonato) Metal Complexes in Multimodal Imaging.

    PubMed

    Cortezon-Tamarit, Fernando; Sarpaki, Sophia; Calatayud, David G; Mirabello, Vincenzo; Pascu, Sofia I

    2016-06-01

    The applications of coordination chemistry to molecular imaging has become a matter of intense research over the past 10 years. In particular, the applications of bis(thiosemicarbazonato) metal complexes in molecular imaging have mainly been focused on compounds with aliphatic backbones due to the in vivo imaging success of hypoxic tumors with PET (positron emission tomography) using (64) CuATSM [copper (diacetyl-bis(N4-methylthiosemicarbazone))]. This compound entered clinical trials in the US and the UK during the first decade of the 21(st) century for imaging hypoxia in head and neck tumors. The replacement of the ligand backbone to aromatic groups, coupled with the exocyclic N's functionalization during the synthesis of bis(thiosemicarbazones) opens the possibility to use the corresponding metal complexes as multimodal imaging agents of use, both in vitro for optical detection, and in vivo when radiolabeled with several different metallic species. The greater kinetic stability of acenaphthenequinone bis(thiosemicarbazonato) metal complexes, with respect to that of the corresponding aliphatic ATSM complexes, allows the stabilization of a number of imaging probes, with special interest in "cold" and "hot" Cu(II) and Ga(III) derivatives for PET applications and (111) In(III) derivatives for SPECT (single-photon emission computed tomography) applications, whilst Zn(II) derivatives display optical imaging properties in cells, with enhanced fluorescence emission and lifetime with respect to the free ligands. Preliminary studies have shown that gallium-based acenaphthenequinone bis(thiosemicarbazonato) complexes are also hypoxia selective in vitro, thus increasing the interest in them as new generation imaging agents for in vitro and in vivo applications. PMID:27149900

  8. Hot subdwarf stars in close-up view. III. Metal abundances of subdwarf B stars

    NASA Astrophysics Data System (ADS)

    Geier, S.

    2013-01-01

    Context. Hot subdwarf B stars (sdBs) are considered to be core helium-burning stars with very thin hydrogen envelopes situated on or near the extreme horizontal branch. The formation of sdBs is still unclear as well as the chemical composition of their atmospheres. The observed helium depletion is attributed to atmospheric diffusion. Metal abundances have been determined for about a dozen sdBs only resulting in puzzling patterns with enrichment of heavy metals and depletion of lighter ones. Aims: We present a detailed metal abundance analysis of 106 sdBs. Methods: From high resolution spectra we measured elemental abundances of up to 24 different ions per star. A semi-automatic analysis pipeline was developed to calculate and fit LTE models to a standard set of spectral lines. Results: A general trend of enrichment was found with increasing temperature for most of the heavier elements. The lighter elements like carbon, oxygen, and nitrogen are depleted and less affected by temperature. Although there is considerable scatter from star to star, the general abundance patterns in most sdBs are similar. State-of-the-art diffusion models predict such patterns and are in qualitative agreement with our results. However, the highest enrichments measured cannot be explained with these models. Peculiar line shapes of the strongest metal lines in some stars indicate vertical stratification to be present in the atmospheres. Such effects are not accounted for in current diffusion models and may be responsible for some of the yet unexplained abundance anomalies. Tables A.1-A.3 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A110

  9. INVESTIGATING THE POTENTIAL DILUTION OF THE METAL CONTENT OF HOT GAS IN EARLY-TYPE GALAXIES BY ACCRETED COLD GAS

    SciTech Connect

    Su, Yuanyuan; Irwin, Jimmy A.

    2013-03-20

    The measured emission-weighted metal abundance of the hot gas in early-type galaxies has been known to be lower than theoretical expectations for 20 years. In addition, both X-ray luminosity and metal abundance vary significantly among galaxies of similar optical luminosities. This suggests some missing factors in the galaxy evolution process, especially the metal enrichment process. With Chandra and XMM-Newton, we studied 32 early-type galaxies (kT {approx}< 1 keV) covering a span of two orders of L{sub X,gas}/L{sub K} to investigate these missing factors. Contrary to previous studies that X-ray faint galaxies show extremely low Fe abundance ({approx}0.1 Z{sub Sun }), nearly all galaxies in our sample show an Fe abundance at least 0.3 Z{sub Sun }, although the measured Fe abundance difference between X-ray faint and X-ray bright galaxies remains remarkable. We investigated whether this dichotomy of hot gas Fe abundances can be related to the dilution of hot gas by mixing with cold gas. With a subset of 24 galaxies in this sample, we find that there is virtually no correlation between hot gas Fe abundances and their atomic gas content, which disproves the scenario that the low metal abundance of X-ray faint galaxies might be a result of the dilution of the remaining hot gas by pristine atomic gas. In contrast, we demonstrate a negative correlation between the measured hot gas Fe abundance and the ratio of molecular gas mass to hot gas mass, although it is unclear what is responsible for this apparent anti-correlation. We discuss several possibilities including that externally originated molecular gas might be able to dilute the hot gas metal content. Alternatively, the measured hot gas Fe abundance may be underestimated due to more complex temperature and abundance structures and even a two-temperature model might be insufficient to reflect the true value of the emission weighted mean Fe abundance.

  10. Antenna induced hot restrike of a ceramic metal halide lamp recorded by high-speed photography

    NASA Astrophysics Data System (ADS)

    Hermanns, P.; Hoebing, T.; Bergner, A.; Ruhrmann, C.; Awakowicz, P.; Mentel, J.

    2016-03-01

    The hot restrike is one of the biggest challenges in operating ceramic metal halide lamps with mercury as buffer gas. Compared to a cold lamp, the pressure within a ceramic burner is two orders of magnitude higher during steady state operation due to the high temperature of the ceramic tube and the resulting high mercury vapour pressure. Room temperature conditions are achieved after 300 s of cooling down in a commercial burner, enclosed in an evacuated outer bulb. At the beginning of the cooling down, ignition voltage rises up to more than 14 kV. A significant reduction of the hot-restrike voltage can be achieved by using a so called active antenna. It is realized by a conductive sleeve surrounding the burner at the capillary of the upper electrode. The antenna is connected to the lower electrode of the lamp, so that its potential is extended to the vicinity of the upper electrode. An increased electric field in front of the upper electrode is induced, when an ignition pulse is applied to the lamp electrodes. A symmetrically shaped ignition pulse is applied with an amplitude, which is just sufficient to re-ignite the hot lamp. The re-ignition, 60 s after switching off the lamp, when the mercury pressure starts to be saturated, is recorded for both polarities of the ignition pulse with a high-speed camera, which records four pictures within the symmetrically shaped ignition pulse with exposure times of 100 ns and throws of 100 ns. The pictures show that the high electric field and its temporal variation establish a local dielectric barrier discharge in front of the upper electrode inside the burner, which covers the inner wall of the burner with a surface charge. It forms a starting point of streamers, which may induce the lamp ignition predominantly within the second half cycle of the ignition pulse. It is found out that an active antenna is more effective when the starting point of the surface streamer in front of the sleeve is a negative surface charge on the

  11. Design of nanophotonic, hot-electron solar-blind ultraviolet detectors with a metal-oxide-semiconductor structure

    NASA Astrophysics Data System (ADS)

    Wang, Zhiyuan; Wang, Xiaoxin; Liu, Jifeng

    2014-12-01

    Solar-blind ultraviolet (UV) detection refers to photon detection specifically in the wavelength range of 200 nm-320 nm. Without background noises from solar radiation, it has broad applications from homeland security to environmental monitoring. The most commonly used solid state devices for this application are wide band gap (WBG) semiconductor photodetectors (Eg > 3.5 eV). However, WBG semiconductors are difficult to grow and integrate with Si readout integrated circuits (ROICs). In this paper, we design a nanophotonic metal-oxide-semiconductor structure on Si for solar-blind UV detectors. Instead of using semiconductors as the active absorber, we use Sn nano-grating structures to absorb UV photons and generate hot electrons for internal photoemission across the Sn/SiO2 interfacial barrier, thereby generating photocurrent between the metal and the n-type Si region upon UV excitation. Moreover, the transported hot electron has an excess kinetic energy >3 eV, large enough to induce impact ionization and generate another free electron in the conduction band of n-Si. This process doubles the quantum efficiency. On the other hand, the large metal/oxide interfacial energy barrier (>3.5 eV) also enables solar-blind UV detection by blocking the less energetic electrons excited by visible photons. With optimized design, ˜75% UV absorption and hot electron excitation can be achieved within the mean free path of ˜20 nm from the metal/oxide interface. This feature greatly enhances hot electron transport across the interfacial barrier to generate photocurrent. The simple geometry of the Sn nano-gratings and the MOS structure make it easy to fabricate and integrate with Si ROICs compared to existing solar-blind UV detection schemes. The presented device structure also breaks through the conventional notion that photon absorption by metal is always a loss in solid-state photodetectors, and it can potentially be extended to other active metal photonic devices.

  12. Effects of hot/wet environments on the fatigue behaviour of composite-to-metal mechanically fastened joints

    SciTech Connect

    Galea, S.C.; Saunders, D.S.

    1993-12-31

    Because of their high strength-to-weight and stiffness-to-weight ratios, carbon fiber reinforced plastic (CFRP) composite laminates are seeing increasing use, especially in the aerospace industry. In composite-to-metal structures the load transfer between various components is undertaken by the use of mechanically fastened or bonded joints. For example, on the F/A-18 aircraft, numerous composite-to-metal mechanically fastened joints are used to transfer loads from the thick composite wing skin to the metal wing ribs and spars. Previous work, undertaken at ARL, has investigated the fatigue of such joints under ambient conditions. It is widely known that the mechanical properties of CFRP laminates generally degrade considerably under hot/wet environments. A similar degradation is expected for mechanically fastened laminates. The aim of this study was to investigate the effects of hot/wet environments on the fatigue behavior of specific mechanically fastened joints. Results showed a marked decrease in the fatigue life of the composite-to-metal mechanically fastened joints under hot/wet environments when compared to lives attained at ambient and under similar load conditions. The major joint failure mode was failure of the fasteners. Other failure modes were compression failure of the 0{degree} ply layers and delamination growth.

  13. Qatar-1b: a hot Jupiter orbiting a metal-rich K dwarf star

    NASA Astrophysics Data System (ADS)

    Alsubai, K. A.; Parley, N. R.; Bramich, D. M.; West, R. G.; Sorensen, P. M.; Collier Cameron, A.; Latham, D. W.; Horne, K.; Anderson, D. R.; Bakos, G. Á.; Brown, D. J. A.; Buchhave, L. A.; Esquerdo, G. A.; Everett, M. E.; Fżrész, G.; Hartman, J. D.; Hellier, C.; Miller, G. M.; Pollacco, D.; Quinn, S. N.; Smith, J. C.; Stefanik, R. P.; Szentgyorgyi, A.

    2011-10-01

    We report the discovery and initial characterization of Qatar-1b, a hot Jupiter-orbiting metal-rich K dwarf star, the first planet discovered by the Qatar Exoplanet Survey. We describe the strategy used to select candidate transiting planets from photometry generated by the Qatar Exoplanet Survey camera array. We examine the rate of astrophysical and other false positives found during the spectroscopic reconnaissance of the initial batch of candidates. A simultaneous fit to the follow-up radial velocities and photometry of Qatar-1b yields a planetary mass of 1.09 ± 0.08 MJ and a radius of 1.16 ± 0.05 RJ. The orbital period and separation are 1.420 033 ± 0.000 016 d and 0.023 43 ± 0.000 26 au for an orbit assumed to be circular. The stellar density, effective temperature and rotation rate indicate an age greater than 4 Gyr for the system.

  14. Analysis of hot forming of a sheet metal component made of advanced high strength steel

    NASA Astrophysics Data System (ADS)

    Demirkaya, Sinem; Darendeliler, Haluk; Gökler, Mustafa İlhan; Ayhaner, Murat

    2013-05-01

    To provide reduction in weight while maintaining crashworthiness and to decrease the fuel consumption of vehicles, thinner components made of Advanced High Strength Steels (AHSS) are being increasingly used in automotive industry. However, AHSS cannot be formed easily at the room temperature (i.e. cold forming). The alternative process involves heating, hot forming and subsequent quenching. A-pillar upper reinforcement of a vehicle is currently being produced by cold forming of DP600 steel sheet with a thickness of 1.8 mm. In this study, the possible decrease in the thickness of this particular part by using 22MnB5 as appropriate AHSS material and applying this alternative process has been studied. The proposed process involves deep drawing, trimming, heating, sizing, cooling and piercing operations. Both the current production process and the proposed process are analyzed by the finite element method. The die geometry, blank holding forces and the design of the cooling channels for the cooling process are determined numerically. It is shown that the particular part made of 22MnB5 steel sheet with a thickness of 1.2 mm can be successfully produced by applying the proposed process sequence and can be used without sacrificing the crashworthiness. With the use of the 22MnB5 steel with a thickness of 1.2 mm instead of DP600 sheet metal with a thickness of 1.8 mm, the weight is reduced by approximately 33%.

  15. Multi-Objective Optimization in Hot Machining of Al/SiCp Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Jadhav, M. R.; Dabade, U. A.

    2016-02-01

    Metal Matrix Composites (MMCs) have been found to be useful in a number of engineering applications and particle reinforced MMCs have received considerable attention due to their excellent engineering properties. These materials are generally regarded as extremely difficult to machine, because of the abrasive characteristics of the reinforced particulates. These characteristics of MMCs affect the machined surface quality and integrity. This paper presents use of Taguchi Grey Relational Analyses (GRA) for optimization of Al/SiCp/10p (220 and 600 mesh) MMCs produced by stir casting. Experiments are performed using L16 orthogonal array by using hot machining technique. The objective of this study is to identify the optimum process parameters to improve the surface integrity on Al/SiCp MMCs. The machined surface integrity has been analyzed by process parameters such as speed, feed, depth of cut and preheating temperature. The significance of the process parameters on surface integrity has been evaluated quantitatively by the analysis of variance (ANOVA) method and AOM plots. The grey relational analysis shows optimum machining conditions as 0.05 mm/rev feed, 0.4 mm depth of cut and 60 °C preheating temperature to enhance surface integrity for both Al/SiCp/10p (220 and 600 mesh) MMCs except for cutting speed 50 and 25 m/min respectively.

  16. Collective excitation of plasmonic hot-spots for enhanced hot charge carrier transfer in metal/semiconductor contacts

    NASA Astrophysics Data System (ADS)

    Piot, Adrien; Earl, Stuart K.; Ng, Charlene; Dligatch, Svetlana; Roberts, Ann; Davis, Timothy J.; Gómez, Daniel E.

    2015-04-01

    We show how a combination of near- and far-field coupling of the localised surface plasmon resonances in aluminium nanoparticles deposited on TiO2 films greatly enhances the visible light photocatalytic activity of the semiconductor material. We demonstrate two orders of magnitude enhancement in the rate of decomposition of methylene blue under visible light illumination when the surface of TiO2 films is decorated with gratings of Al nanoparticle dimers.We show how a combination of near- and far-field coupling of the localised surface plasmon resonances in aluminium nanoparticles deposited on TiO2 films greatly enhances the visible light photocatalytic activity of the semiconductor material. We demonstrate two orders of magnitude enhancement in the rate of decomposition of methylene blue under visible light illumination when the surface of TiO2 films is decorated with gratings of Al nanoparticle dimers. Electronic supplementary information (ESI) available: Detailed information on estimates of hot-electron injection efficiencies, electrodynamic simulations, sample preparation, spectroscopic and structural characterization and photocatalytic experiments. See DOI: 10.1039/c5nr01592h

  17. Evaluation of alkali metal sulfate dew point measurement for detection of hot corrosion conditions in PFBC flue gas

    SciTech Connect

    Helt, J.E.

    1980-11-01

    Hot corrosion in combustion systems is, in general, the accelerated oxidation of nickel, cobalt, and iron-base alloys which occurs in the presence of small amounts of impurities - notably, sodium, sulfur, chlorine, and vanadium. There is no real consensus on which mechanisms are primarily responsible for high-temperature corrosion. One point generally accepted, however, is that corrosion reactions take place at an appreciable rate only in the presence of a liquid phase. When coal is the fuel for combustion, hot corrosion may occur in the form of accelerated sulfidation. It is generally agreed by investigators that molten alkali metal sulfates (Na/sub 2/SO/sub 4/ and K/sub 2/SO/sub 4/) are the principal agents responsible for the occurrence of sulfidation. Although molten sodium sulfate by itself appears to have little or no effect on the corrosion of metal alloys, its presence may increase the accessibility of the bare metal surface to the external atmosphere. If this atmosphere contains either a reductant and/or an oxide such as SiO/sub 2/, SO/sub 3/, or NaOH(Na/sub 2/O), corrosion is likely to occur. Alkali metal sulfate dew point measurement was evaluated as a means of anticipating hot corrosion in the gas turbine of a pressurized fluidized-bed combustion system. The hot corrosion mechanism and deposition rate theory were reviewed. Two methods of dew point measurement, electrical conductivity and remote optical techniques, were identified as having a potential for this application. Both techniques are outlined; practical measurement systems are suggested; and potential problem areas are identified.

  18. Microstructure and mechanical properties of hip-consolidated Rene 95 powders. [hot-isostatic pressed nickel-based powder metal

    NASA Technical Reports Server (NTRS)

    Shimanuki, Y.; Nishino, Y.; Masui, M.; Doi, H.

    1980-01-01

    The effects of heat-treatments on the microstructure of P/M Rene 95 (a nickel-based powder metal), consolidated by the hot-isostatic pressing (HIP), were examined. The microstructure of as-HIP'd specimen was characterized by highly serrated grain boundaries. Mechanical tests and microstructural observations reveal that the serrated grain boundaries improved ductility at both room and elevated temperatures by retarding crack propagation along grain boundaries.

  19. Heavy metal accumulation in hot water tanks in a region experiencing coal waste pollution and comparison between regional water systems

    SciTech Connect

    Wigginton, A.; McSpirit, S.; Sims, C.D.

    2007-10-15

    In 2000, a coal slurry impoundment failure in Martin County, Kentucky, caused concerns about contaminants entering municipal water supplies. Water samples taken from impacted and reference area hot water tanks often exceeded US EPA drinking water guidelines. Concentrations of As, Cd, Cr, Cu, Fe, Mn, and Pb had maxima of 119; 51.9; 154; 170,000; 976,000; 8,710; and 12,700 {mu}g/L, respectively. Significantly different metal accumulation between counties indicated this procedure's utility for assessing long-term municipal water quality. Correlations between metal concentrations were strong and consistent for As, Ba, Cd, Cr, Co, and Fe indicating that some metals accumulate proportionally with others.

  20. Analysis of microstructure-dependent shock dissipation and hot-spot formation in granular metalized explosive

    NASA Astrophysics Data System (ADS)

    Chakravarthy, Sunada; Gonthier, Keith A.

    2016-07-01

    Variations in the microstructure of granular explosives (i.e., particle packing density, size, shape, and composition) can affect their shock sensitivity by altering thermomechanical fields at the particle-scale during pore collapse within shocks. If the deformation rate is fast, hot-spots can form, ignite, and interact, resulting in burn at the macro-scale. In this study, a two-dimensional finite and discrete element technique is used to simulate and examine shock-induced dissipation and hot-spot formation within low density explosives (68%-84% theoretical maximum density (TMD)) consisting of large ensembles of HMX (C4H8N8O8) and aluminum (Al) particles (size ˜ 60 -360 μm). Emphasis is placed on identifying how the inclusion of Al influences effective shock dissipation and hot-spot fields relative to equivalent ensembles of neat/pure HMX for shocks that are sufficiently strong to eliminate porosity. Spatially distributed hot-spot fields are characterized by their number density and area fraction enabling their dynamics to be described in terms of nucleation, growth, and agglomeration-dominated phases with increasing shock strength. For fixed shock particle speed, predictions indicate that decreasing packing density enhances shock dissipation and hot-spot formation, and that the inclusion of Al increases dissipation relative to neat HMX by pressure enhanced compaction resulting in fewer but larger HMX hot-spots. Ensembles having bimodal particle sizes are shown to significantly affect hot-spot dynamics by altering the spatial distribution of hot-spots behind shocks.

  1. Imaging challenges in 20nm and 14nm logic nodes: hot spots performance in Metal1 layer

    NASA Astrophysics Data System (ADS)

    Timoshkov, V.; Rio, D.; Liu, H.; Gillijns, W.; Wang, J.; Wong, P.; Van Den Heuvel, D.; Wiaux, V.; Nikolsky, P.; Finders, J.

    2013-10-01

    The 20nm Metal1 layer, based on ARM standard cells, has a 2D design with minimum pitch of 64nm. This 2D design requires a Litho-Etch-Litho-Etch (LELE) double patterning. The whole design is divided in 2 splits: Me1A and Me1B. But solution of splitting conflicts needs stitching at some locations, what requires good Critical Dimension (CD) and overlay control to provide reliable contact between 2 stitched line ends. ASML Immersion NXT tools are aimed at 20 and 14nm logic production nodes. Focus control requirements become tighter, as existing 20nm production logic layouts, based on ARM, have about 50-60nm focus latitude and tight CD Uniformity (CDU) specifications, especially for line ends. IMEC inspected 20nm production Metal1 ARM standard cells with a Negative Tone Development (NTD) process using the Process Window Qualification-like technique experimentally and by Brion Tachyon LMC by simulations. Stronger defects were found thru process variations. A calibrated Tachyon model proved a good overall predictability capability for this process. Selected defects are likely to be transferred to hard mask during etch. Further, CDU inspection was performed for these critical features. Hot spots showed worse CD uniformity than specifications. Intra-field CDU contribution is significant in overall CDU budget, where reticle has major impact due to high MEEF of hot spots. Tip-to-Tip and tip-to-line hot spots have high MEEF and its variation over the field. Best focus variation range was determined by best focus offsets between hot spots and its variation within the field.

  2. BROAD H I ABSORBERS AS METALLICITY-INDEPENDENT TRACERS OF THE WARM-HOT INTERGALACTIC MEDIUM

    SciTech Connect

    Danforth, Charles W.; Stocke, John T.; Shull, J. Michael E-mail: john.stocke@colorado.ed

    2010-02-10

    Thermally broadened Lyalpha absorbers (BLAs) offer an alternative method to highly ionized metal lines for tracing the warm-hot intergalactic medium (WHIM) at T>10{sup 5} K. However, observing BLAs requires data of high quality and accurate continuum definition to detect the low-contrast features, and a good knowledge of the velocity structure to differentiate multiple blended components from a single broad line. Even for well-characterized absorption profiles, disentangling the thermal line width from the various thermal and non-thermal contributors to the observed line width is ambiguous. We compile a catalog of reliable BLA candidates along seven active galactic nucleus sight lines from a larger set of Lyalpha absorbers observed by the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST). We compare our measurements based on independent reduction and analysis of the data to those published by other research groups. We examine the detailed structure of each absorber and determine a reliable line width and column density. Purported BLAs are grouped into probable (15), possible (48), and non-BLA (56) categories. Combining the first two categories, we infer a line frequency (dN/dz){sub BLA}=18+-11, comparable to observed O VI absorbers, also thought to trace the WHIM. We discuss the overlap between BLA and O VI absorbers (20%-40%) and the distribution of BLAs in relation to nearby galaxies (O VI detections in BLAs are found closer to galaxies than O VI nondetections). We assume that the line width determined through a multi-line curve of growth (COG) is a close approximation to the thermal line width. Based on 164 measured COG H I line measurements, we statistically correct the observed line widths via a Monte Carlo simulation. Gas temperature and neutral fraction f{sub H{sub I}} are inferred from these statistically corrected line widths and lead to a distribution of total hydrogen columns. Summing the total column density over the total

  3. Thermal characteristics of air-water spray impingement cooling of hot metallic surface under controlled parametric conditions

    NASA Astrophysics Data System (ADS)

    Nayak, Santosh Kumar; Mishra, Purna Chandra

    2016-06-01

    Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper. The controlling input parameters investigated were the combined air and water pressures, plate thickness, water flow rate, nozzle height from the target surface and initial temperature of the hot surface. The effects of these input parameters on the important thermal characteristics such as heat transfer rate, heat transfer coefficient and wetting front movement were measured and examined. Hot flat plate samples of mild steel with dimension 120 mm in length, 120 mm breadth and thickness of 4 mm, 6 mm, and 8 mm respectively were tested. The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface. Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e, 4 mm thick plates. Increase in the nozzle height reduced the heat transfer efficiency of spray cooling. At an inlet water pressure of 4 bar and air pressure of 3 bar, maximum cooling rates 670°C/s and average cooling rate of 305.23°C/s were achieved for a temperature of 850°C of the steel plate.

  4. Valley-Coherent Hot Carriers and Thermal Relaxation in Monolayer Transition Metal Dichalcogenides.

    PubMed

    Kallatt, Sangeeth; Umesh, Govindarao; Majumdar, Kausik

    2016-06-01

    We show room-temperature valley coherence in MoS2, MoSe2, WS2, and WSe2 monolayers using linear polarization-resolved hot photoluminescence (PL) at energies close to the excitation, demonstrating preservation of valley coherence before sufficient scattering events. The features of the copolarized hot luminescence allow us to extract the lower bound of the binding energy of the A exciton in monolayer MoS2 as 0.42 (±0.02) eV. The broadening of the PL peak is found to be dominated by a Boltzmann-type hot luminescence tail, and using the slope of the exponential decay, the carrier temperature is extracted in situ at different stages of energy relaxation. The temperature of the emitted optical phonons during the relaxation process is probed by exploiting the corresponding broadening of the Raman peaks due to temperature-induced anharmonic effects. The findings provide a physical picture of photogeneration of valley-coherent hot carriers and their subsequent energy relaxation pathways.

  5. Automated Nondestructive Evaluation Method for Characterizing Ceramic and Metallic Hot Gas Filters

    SciTech Connect

    Ellingson, W.A.; Pastila, P.; Koehl, E.R.; Wheeler, B.; Deemer, C.; Forster, G.A.

    2002-09-19

    The objective of this work was to develop a nondestructive (NDE), cost-effective and reliable method to assess the condition of rigid ceramic hot gas filters. The work was intended to provide an end user, as well as filter producers, with a nondestructive method to assess the ''quality'' or status of the filters.

  6. Liquid Metal Embrittlement in Resistance Spot Welding and Hot Tensile Tests of Surface-refined TWIP Steels

    NASA Astrophysics Data System (ADS)

    Barthelmie, J.; Schram, A.; Wesling, V.

    2016-03-01

    Automotive industry strives to reduce vehicle weight and therefore fuel consumption and carbon dioxide emissions. Especially in the auto body, material light weight construction is practiced, but the occupant safety must be ensured. These requirements demand high-strength steels with good forming and crash characteristics. Such an approach is the use of high- manganese-content TWIP steels, which achieve strengths of around 1,000 MPa and fracture strains of more than 60%. Welding surface-refined TWIP steels reduces their elongation at break and produces cracks due to the contact with liquid metal and the subsequent liquid metal embrittlement (LME). The results of resistance spot welds of mixed joints of high-manganese- content steel in combination with micro-alloyed ferritic steel and hot tensile tests are presented. The influence of different welding parameters on the sensitivity to liquid metal embrittlement is investigated by means of spot welding. In a high temperature tensile testing machine, the influence of different parameters is determined regardless of the welding process. Defined strains just below or above the yield point, and at 25% of elongation at break, show the correlation between the applied strain and liquid metal crack initiation. Due to the possibility to carry out tensile tests on a wide range of temperatures, dependencies of different temperatures of the zinc coating to the steel can be identified. Furthermore, the attack time of the zinc on the base material is investigated by defined heating periods.

  7. A HOT URANUS ORBITING THE SUPER METAL-RICH STAR HD 77338 AND THE METALLICITY-MASS CONNECTION

    SciTech Connect

    Jenkins, J. S.; Hoyer, S.; Jones, M. I.; Rojo, P.; Day-Jones, A. C.; Ruiz, M. T.; Jones, H. R. A.; Tuomi, M.; Barnes, J. R.; Pavlenko, Y. V.; Pinfield, D. J.; Murgas, F.; Ivanyuk, O.; Jordan, A.

    2013-04-01

    We announce the discovery of a low-mass planet orbiting the super metal-rich K0V star HD 77338 as part of our ongoing Calan-Hertfordshire Extrasolar Planet Search. The best-fit planet solution has an orbital period of 5.7361 {+-} 0.0015 days and with a radial velocity semi-amplitude of only 5.96 {+-} 1.74 ms{sup -1}, we find a minimum mass of 15.9{sup +4.7}{sub -5.3} M{sub Circled-Plus }. The best-fit eccentricity from this solution is 0.09{sup +0.25}{sub -0.09}, and we find agreement for this data set using a Bayesian analysis and a periodogram analysis. We measure a metallicity for the star of +0.35 {+-} 0.06 dex, whereas another recent work finds +0.47 {+-} 0.05 dex. Thus HD 77338b is one of the most metal-rich planet-host stars known and the most metal-rich star hosting a sub-Neptune-mass planet. We searched for a transit signature of HD 77338b but none was detected. We also highlight an emerging trend where metallicity and mass seem to correlate at very low masses, a discovery that would be in agreement with the core accretion model of planet formation. The trend appears to show that for Neptune-mass planets and below, higher masses are preferred when the host star is more metal-rich. Also a lower boundary is apparent in the super metal-rich regime where there are no very low mass planets yet discovered in comparison to the sub-solar metallicity regime. A Monte Carlo analysis shows that this low-mass planet desert is statistically significant with the current sample of 36 planets at the {approx}4.5{sigma} level. In addition, results from Kepler strengthen the claim for this paucity of the lowest-mass planets in super metal-rich systems. Finally, this discovery adds to the growing population of low-mass planets around low-mass and metal-rich stars and shows that very low mass planets can now be discovered with a relatively small number of data points using stable instrumentation.

  8. Studies of plasmonic hot-spot translation by a metal-dielectric layered superlens

    NASA Astrophysics Data System (ADS)

    Thoreson, Mark D.; Nielsen, Rasmus B.; West, Paul R.; Kriesch, Arian; Liu, Zhengtong; Fang, Jieran; Kildishev, Alexander V.; Peschel, Ulf; Shalaev, Vladimir M.; Boltasseva, Alexandra

    2011-10-01

    We have studied the ability of a lamellar near-field superlens to transfer an enhanced electromagnetic field to the far side of the lens. In this work, we have experimentally and numerically investigated superlensing in the visible range. By using the resonant hot-spot field enhancements from optical nanoantennas as sources, we investigated the translation of these sources to the far side of a layered silver-silica superlens operating in the canalization regime. Using near-field scanning optical microscopy (NSOM), we have observed evidence of superlens-enabled enhanced-field translation at a wavelength of about 680 nm. Specifically, we discuss our recent experimental and simulation results on the translation of hot spots using a silver-silica layered superlens design. We compare the experimental results with our numerical simulations and discuss the perspectives and limitations of our approach.

  9. Hot electron transport in a strongly correlated transition-metal oxide

    PubMed Central

    Rana, Kumari Gaurav; Yajima, Takeaki; Parui, Subir; Kemper, Alexander F.; Devereaux, Thomas P.; Hikita, Yasuyuki; Hwang, Harold Y.; Banerjee, Tamalika

    2013-01-01

    Oxide heterointerfaces are ideal for investigating strong correlation effects to electron transport, relevant for oxide-electronics. Using hot-electrons, we probe electron transport perpendicular to the La0.7Sr0.3MnO3 (LSMO)- Nb-doped SrTiO3 (Nb:STO) interface and find the characteristic hot-electron attenuation length in LSMO to be 1.48 ± 0.10 unit cells (u.c.) at −1.9 V, increasing to 2.02 ± 0.16 u.c. at −1.3 V at room temperature. Theoretical analysis of this energy dispersion reveals the dominance of electron-electron and polaron scattering. Direct visualization of the local electron transport shows different transmission at the terraces and at the step-edges. PMID:23429420

  10. Observations of the Hot Horizontal Branch Stars in the Metal-Rich Bulge Globular Cluster NGC 6388

    NASA Technical Reports Server (NTRS)

    Moehler, S.; Sweigart, A. V.

    2006-01-01

    The metal-rich bulge globular cluster NGC 6388 shows a distinct blue horizontal-branch tail in its colour-magnitude diagram (Rich et al. 1997) and is thus a strong case of the well-known 2nd Parameter Problem. In addition, its horizontal branch (HB) shows an upward tilt toward bluer colours, which cannot be explained by canonical evolutionary models. Several non-canonical scenarios have been proposed to explain these puzzling observations. In order to test the predictions of these scenarios, we have obtained medium resolution spectra to determine the atmospheric parameters of a sample of the blue HB stars in NGC 6388.Using the medium resolution spectra, we determine effective temperatures, surface gravities and helium abundances by fitting the observed Balmer and helium lines with appropriate theoretical stellar spectra. As we know the distance to the cluster, we can verify our results by determining masses for the stars. During the data reduction we took special care to correctly subtract the background, which is dominated by the overlapping spectra of cool stars. The cool blue tail stars in our sample with T(sub eff) approximately 10000 K have lower than canonical surface gravities, suggesting that these stars are, on average, approximately equal to 0.4 mag brighter than canonical HB stars in agreement with the observed upward slope of the HB in NGC 6388. Moreover, the mean mass of these stars agrees well with theoretical predictions. In contrast, the hot blue tail stars in our sample with T(sub eff) greater than or equal to 12000 K show significantly lower surface gravities than predicted by any scenario, which can reproduce the photometric observations. Their masses are also too low by about a factor of 2 compared to theoretical predictions. The physical parameters of the blue HB stars at about 10,000 K support the helium pollution scenario. The low gravities and masses of the hot blue tail stars, however, are probably caused by problems with the data reduction

  11. The hot DOA1 degenerate HZ 21 - A search for circumstellar/photospheric metals and peculiar absorption at He II

    NASA Technical Reports Server (NTRS)

    Fritz, M. L.; Leckenby, H.; Sion, E. M.; Vauclair, G.; Liebert, J.

    1990-01-01

    A high-resolution IUE spectrum of the hot DO1 degenerate HZ 21 was obtained by combining US1 + European 2 low-background observing shifts. The SWP image reveals a rich spectrum of interstellar absorption lines with an average velocity in the line of sight to HZ 21 of -30 km/s. However, there is no clear evidence of any highly or lowly ionized metal features which could be attributed to circumstellar, wind, or photospheric absorption. There is, however, a broad absorption trough at He II (1640) which was not unexpected, given the clear presence of He II (4686) absorption in this star's optical spectrum. The velocity width of He II (1640) appears consistent with photospheric absorption wings which appear to flank the geocoronal Ly-alpha emission feature. The He II (1640) feature reveals what appears to be a broad (310 km/s) emission reversal. Evidence is provided that the emission reversal is probably real.

  12. Hot, Massive Stars in the Extremely Metal-Poor Galaxy, I Zw 18

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Malumuth, Eliot M.

    2010-01-01

    The carbon-enhanced metal-poor galaxy, I Zw 18, is the Rosetta Stone for understanding galaxies in the early universe by providing constraints on the IMF of massive stars, the role of galaxies in reionization of the universe, mixing of newly synthesized material in the ISM, and gamma-ray bursts at low metallicity, and on the earliest generations of stars producing the observed abundance pattern. We describe these constraints as derived from analyses of HST/COS spectra of I Zw 18 including stellar atmosphere analysis and photo-ionization modeling of both the emission and absorption spectra of the nebular material and interstellar medium.

  13. Identifying Hot-Spots of Metal Contamination in Campus Dust of Xi'an, China.

    PubMed

    Chen, Hao; Lu, Xinwei; Gao, Tianning; Chang, Yuyu

    2016-01-01

    The concentrations of heavy metals (As, Ba, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) in campus dust from kindergartens, elementary schools, middle schools, and universities in the city of Xi'an, China, were determined by X-ray fluorescence spectrometry. The pollution levels and hotspots of metals were analyzed using a geoaccumulation index and Local Moran's I, an indicator of spatial association, respectively. The dust samples from the campuses had metal concentrations higher than background levels, especially for Pb, Zn, Co, Cu, Cr, and Ba. The pollution assessment indicated that the campus dusts were not contaminated with As, Mn, Ni, or V, were moderately or not contaminated with Ba and Cr and were moderately to strongly contaminated with Co, Cu, Pb, and Zn. Local Moran's I analysis detected the locations of spatial clusters and outliers and indicated that the pollution with these 10 metals occurred in significant high-high spatial clusters, low-high, or even high-low spatial outliers. As, Cu, Mn, Ni, Pb, V, and Zn had important high-high patterns in the center of Xi'an. The western and southwestern regions of the study area, i.e., areas of old and high-tech industries, have strongly contributed to the Co content in the campus dust. PMID:27271645

  14. Identifying Hot-Spots of Metal Contamination in Campus Dust of Xi’an, China

    PubMed Central

    Chen, Hao; Lu, Xinwei; Gao, Tianning; Chang, Yuyu

    2016-01-01

    The concentrations of heavy metals (As, Ba, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) in campus dust from kindergartens, elementary schools, middle schools, and universities in the city of Xi’an, China, were determined by X-ray fluorescence spectrometry. The pollution levels and hotspots of metals were analyzed using a geoaccumulation index and Local Moran’s I, an indicator of spatial association, respectively. The dust samples from the campuses had metal concentrations higher than background levels, especially for Pb, Zn, Co, Cu, Cr, and Ba. The pollution assessment indicated that the campus dusts were not contaminated with As, Mn, Ni, or V, were moderately or not contaminated with Ba and Cr and were moderately to strongly contaminated with Co, Cu, Pb, and Zn. Local Moran’s I analysis detected the locations of spatial clusters and outliers and indicated that the pollution with these 10 metals occurred in significant high-high spatial clusters, low-high, or even high-low spatial outliers. As, Cu, Mn, Ni, Pb, V, and Zn had important high-high patterns in the center of Xi’an. The western and southwestern regions of the study area, i.e., areas of old and high-tech industries, have strongly contributed to the Co content in the campus dust. PMID:27271645

  15. Electron-electron scattering-induced channel hot electron injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors with high-k/metal gate stacks

    SciTech Connect

    Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Ho, Szu-Han; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen

    2014-10-06

    This work investigates electron-electron scattering (EES)-induced channel hot electron (CHE) injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors (n-MOSFETs) with high-k/metal gate stacks. Many groups have proposed new models (i.e., single-particle and multiple-particle process) to well explain the hot carrier degradation in nanoscale devices and all mechanisms focused on Si-H bond dissociation at the Si/SiO{sub 2} interface. However, for high-k dielectric devices, experiment results show that the channel hot carrier trapping in the pre-existing high-k bulk defects is the main degradation mechanism. Therefore, we propose a model of EES-induced CHE injection to illustrate the trapping-dominant mechanism in nanoscale n-MOSFETs with high-k/metal gate stacks.

  16. Molybdenum-based additives to mixed-metal oxides for use in hot gas cleanup sorbents for the catalytic decomposition of ammonia in coal gases

    DOEpatents

    Ayala, Raul E.

    1993-01-01

    This invention relates to additives to mixed-metal oxides that act simultaneously as sorbents and catalysts in cleanup systems for hot coal gases. Such additives of this type, generally, act as a sorbent to remove sulfur from the coal gases while substantially simultaneously, catalytically decomposing appreciable amounts of ammonia from the coal gases.

  17. Carbon formation and metal dusting in hot-gas cleanup systems of coal gasifiers

    SciTech Connect

    Judkins, R.R.; Tortorelli, P.F.; Judkins, R.R.; DeVan, J.H.; Wright, I.G.

    1995-11-01

    The product gas resulting from the partial oxidation of Carboniferous materials in a gasifier is typically characterized by high carbon and sulfur, but low oxygen, activities and, consequently, severe degradation of the structural and functional materials can occur. The objective of this task was to establish the potential risks of carbon deposition and metal dusting in advanced coal gasification processes by examining the current state of knowledge regarding these phenomena, making appropriate thermochemical calculations for representative coal gasifiers, and addressing possible mitigation methods. The paper discusses carbon activities, iron-based phase stabilities, steam injection, conditions that influence kinetics of carbon deposition, and influence of system operating parameters on carbon deposition and metal dusting.

  18. Triangulum II: A Very Metal-poor and Dynamically Hot Stellar System

    NASA Astrophysics Data System (ADS)

    Martin, Nicolas F.; Ibata, Rodrigo A.; Collins, Michelle L. M.; Rich, R. Michael; Bell, Eric F.; Ferguson, Annette M. N.; Laevens, Benjamin P. M.; Rix, Hans-Walter; Chapman, Scott C.; Koch, Andreas

    2016-02-01

    We present a study of the recently discovered compact stellar system Triangulum II. From observations conducted with the DEIMOS spectrograph on Keck II, we obtained spectra for 13 member stars that follow the CMD features of this very faint stellar system and include two bright red giant branch stars. Tri II has a very negative radial velocity (< {v}{{r}}> =-{383.7}-3.3+3.0 {km} {{{s}}}-1) that translates to < {v}{{r},{gsr}}> ≃ -264 {km} {{{s}}}-1 and confirms it is a Milky Way satellite. We show that, despite the small data set, there is evidence that Tri II has complex internal kinematics. Its radial velocity dispersion increases from {4.4}-2.0+2.8 {km} {{{s}}}-1 in the central 2\\prime to {14.1}-4.2+5.8 {km} {{{s}}}-1 outwards. The velocity dispersion of the full sample is inferred to be {σ }{vr}={9.9}-2.2+3.2 {km} {{{s}}}-1. From the two bright RGB member stars we measure an average metallicity < {{[Fe/H]}}> =-2.6+/- 0.2, placing Tri II among the most metal-poor Milky Way dwarf galaxies. In addition, the spectra of the fainter member stars exhibit differences in their line widths that could be the indication of a metallicity dispersion in the system. All these properties paint a complex picture for Tri II, whose nature and current state are largely speculative. The inferred metallicity properties of the system however lead us to favor a scenario in which Tri II is a dwarf galaxy that is either disrupting or embedded in a stellar stream.

  19. Efficient and Robust Thermoelectric Power Generation Device Using Hot-Pressed Metal Contacts on Nanostructured Half-Heusler Alloys

    NASA Astrophysics Data System (ADS)

    Joshi, Giri; Poudel, Bed

    2016-06-01

    We report an efficient thermoelectric device with power density of 8.9 W/cm2 and efficiency of 8.9% at 678°C temperature difference using hot-pressed titanium metal contact layers on nanostructured half-Heusler materials. The high power density and efficiency are due to the efficient nanostructured materials and very low contact resistance of ~1 μΩ cm2 between the titanium layer and half-Heusler material. Moreover, the bonding strength between the titanium and half-Heusler is more than 50 MPa, significantly higher compared with conventional contact metallization methods. The low contact resistance and high bonding strength are due to thin-layer diffusion of titanium (<100 μm) into the half-Heusler at high temperature (>600°C). The low contact resistance and high bonding strength result in a stable and efficient power generation device with great potential for use in recovery of waste heat, e.g., in automotive and industrial applications.

  20. Vapor Explosion of Coolant Jet When Penetrating a Hot Molten Metal

    SciTech Connect

    Perets, Y.; Harari, R.; Sher, E.

    2005-06-15

    The vapor explosion phenomenon is investigated experimentally for a geometrical arrangement in which a cold liquid (water) jet is injected into a hot liquid surface (tin). Medium-scale experiments using 1 kg of molten tin were performed in an open geometry experiment system. In the first phase of the research, the influence of the injection mass flow rate on the likelihood of vapor explosion was investigated in order to map the various relevant regimes. In the second phase, the influence of some selected parameters on the interaction was studied to characterize the relevant parameters of the vapor explosion phenomenon.The range of the initial tin and water temperatures that leads to vapor explosion has been determined in order to define the thermal interaction zone. It is noticed that vapor explosion can occur at high water temperatures even near the saturation point. The delay time for the explosion to occur and the degree of the interaction violence were correlated with the initial tin and water temperatures. We also clarified the triggering point and noted a correlation between the quench temperature and the likelihood of the vapor explosion occurrence.

  1. Hot isostatic pressing of SiC particulate reinforced metal matrix composites

    SciTech Connect

    Loh, N.L.; Wei, Z.; Xu, Z.

    1996-12-31

    Two as-cast SiC particulate reinforced A359-based composites were hot isostatically pressed for a fixed length of time but at various pressures (in the range 100--150 MPa) and temperatures (in the range 450--550 C). It was found that HIP treatment generally increased the ductility but reduced the yield stress drastically. The improvement of ductility was attributed to a reduction of the porosity levels. Quantitative image analyses showed that the HIP treatment reduced the porosity levels significantly. It is of interest to observe that increasing HIP temperature is more effective than increasing HIP pressure in terms of improvement in strength and ductility. Another interesting observation is that most eutectic Si particles were spheroidized during HIP. The spheroidization of Si was believed to contribute to the improvement of mechanical properties, because fracture initiation of the composites was observed to be related to either the breaking of Si particles or the debonding of Si particles from the nearby SiC particles.

  2. Optical spectra of hot alkali-metal clusters from the random-matrix model

    SciTech Connect

    Akulin, V.M.; Brechignac, C.; Sarfati, A.

    1997-01-01

    We show that the experimentally observed spectra of optical absorption of sodium cluster ions can be explained in the framework of the same random-matrix model, that has been employed earlier [Phys. Rev. Lett. {bold 75}, 220 (1995)] for the ground-state properties of alkali-metal clusters. This approach reveals the effect of cluster symmetry {open_quotes}on average{close_quotes} on the optical-absorption profiles, describes their temperature dependence, and predicts the line shapes of two-photon absorption. {copyright} {ital 1996} {ital The American Physical Society}

  3. Literature review of metal corrosion sensitivity in high temperature, high impurity hot cell atmospheres

    SciTech Connect

    Eberle, C.S.

    1997-09-01

    The pyrochemical conditions of spent nuclear fuel for the purpose of final disposal is being demonstrated at Argonne National Laboratory (ANL). One aspect of this program is to develop a lithium preprocessing stage for the Fuel Conditioning Facility (FCF). One of the design considerations under investigation in this program is the system`s corrosion response in the presence of irradiated commercial fuel as well as atmospheric impurities. Static corrosion coupon tests have been completed which demonstrate the potential corrosivity of the salt matrix in a worse case environment as well as provide a boundary for allowable impurities in the system during operation. The literature concerning corrosion of either fused salts or molten metals consistently emphasizes three similar features which are common to both systems: (1) the overall corrosion rate is strongly dependent on temperature, impurity concentration and flow velocity; (2) many different mechanisms can be involved in a specific corrosion process; and (3) corrosion rates will significantly increase as all three of these independent variables are increased. The qualitative and quantitative understanding of these corrosion results is important for this spent fuel program since all of these variables will increase as the process scale increases. The purpose of this work was to determine if any data existed which could provide a quantitative expectation for corrosion rates of refractory metals in a lithium chloride salt bath.

  4. Synergistic effects of plant growth-promoting Neorhizobium huautlense T1-17 and immobilizers on the growth and heavy metal accumulation of edible tissues of hot pepper.

    PubMed

    Chen, Ling; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

    2016-07-15

    A plant growth-promoting Neorhizobium huautlense T1-17 was evaluated for its immobilization of Cd and Pb in solution. Meanwhile, the impacts of T1-17, immobilizers (vermiculite and peat) and their combination on the fruit biomass and heavy metal accumulation of hot pepper were characterized. T1-17 could significantly reduced water-soluble Cd and Pb in solution. T1-17, vermiculite+T1-17, peat, and peat+T1-17 significantly increased the fruit biomass (ranging from 45% to 269%) and decreased the fruit Cd (ranging from 66% to 87%) and Pb (ranging from 30% to 56%) contents and water-soluble Cd and Pb (ranging from 23% to 59%) contents of the rhizosphere soils compared to the controls. T1-17+vermiculite or peat had higher ability to increase the fruit biomass than T1-17 or vermiculite or peat. Furthermore, T1-17+peat had higher ability to reduce the water-soluble Cd and Pb contents of the rhizosphere soil and the fruit Pb uptake of hot pepper. The results showed that T1-17 and the immobilizers alleviated the heavy metal toxicity and decreased the fruit heavy metal uptake of hot pepper. The results also showed the synergistic effects of T1-17 and the immobilizers on the growth and Cd and Pb accumulation of hot pepper.

  5. HATS-4b: A dense hot Jupiter transiting a super metal-rich G star

    SciTech Connect

    Jordán, Andrés; Brahm, Rafael; Rabus, M.; Suc, V.; Espinoza, N.; Bakos, G. Á.; Penev, K.; Hartman, J. D.; Csubry, Z.; Bhatti, W.; De Val Borro, M.; Bayliss, D.; Zhou, G.; Mancini, L.; Mohler-Fischer, M.; Ciceri, S.; Csák, B.; Henning, T.; Sato, B.; Buchhave, L.; and others

    2014-08-01

    We report the discovery by the HATSouth survey of HATS-4b, an extrasolar planet transiting a V = 13.46 mag G star. HATS-4b has a period of P ≈ 2.5167 days, mass of M{sub p} ≈ 1.32 M {sub Jup}, radius of R{sub p} ≈ 1.02 R {sub Jup}, and density of ρ {sub p} = 1.55 ± 0.16 g cm{sup –3} ≈1.24 ρ{sub Jup}. The host star has a mass of 1.00 M {sub ☉}, a radius of 0.92 R {sub ☉}, and a very high metallicity [Fe/H]=0.43 ± 0.08. HATS-4b is among the densest known planets with masses between 1 and 2 M {sub J} and is thus likely to have a significant content of heavy elements of the order of 75 M {sub ⊕}. In this paper we present the data reduction, radial velocity measurements, and stellar classification techniques adopted by the HATSouth survey for the CORALIE spectrograph. We also detail a technique for simultaneously estimating vsin i and macroturbulence using high resolution spectra.

  6. Multiscale and Fractal Analysis of Silicon Content Time Series Observed in Blast Furnace Hot Metal Using Hurst Exponent Chain

    NASA Astrophysics Data System (ADS)

    Luo, Shihua; Guo, Fan; Lai, Dejian; Yan, Fang; Tang, Feilai

    2015-09-01

    Hurst exponent is an important measure of nonlinearity of dynamical time series. In this paper, using rescaled-range (R/S) analysis, multi-fractal detrended fluctuation analysis (MF-DFA) methods, the multiscale Hurst exponent (MHE) and the multiscale generalized Hurst exponent (MGHE) of coarse-grained silicon content ([Si]) time series in blast furnace (BF) hot metal were calculated. First, we collected these [Si] time series from No. 1 BF of Nanchang Iron and Steel Co. and No. 10 BF of Xinyu Iron and Steel Co. in Jiangxi Province, China. Then, we analyzed and compared the estimated Hurst exponents and the generalized Hurst exponent of these observed time series with some simulated time series. Our results show that the observed time series from these BFs have negative correlation with the Hurst exponent less than 0.5, the generalized Hurst exponent H(q) is a nonlinear function of q, and such negative correlation and local various structure persist in their moving averages of the observed time series up to lag 5 or 10.

  7. NUCLEOSYNTHESIS IN HIGH-ENTROPY HOT BUBBLES OF SUPERNOVAE AND ABUNDANCE PATTERNS OF EXTREMELY METAL-POOR STARS

    SciTech Connect

    Izutani, Natsuko; Umeda, Hideyuki E-mail: umeda@astron.s.u-tokyo.ac.j

    2010-09-01

    There have been suggestions that the abundance of extremely metal-poor (EMP) stars can be reproduced by hypernovae (HNe), not by normal supernovae (SNe). However, recently it was also suggested that if the innermost neutron-rich or proton-rich matter is ejected, the abundance patterns of ejected matter are changed, and normal SNe may also reproduce the observations of EMP stars. In this Letter, we calculate explosive nucleosynthesis with various Y {sub e} and entropy, and investigate whether normal SNe with this innermost matter, which we call the 'hot-bubble' component, can reproduce the abundance of EMP stars. We find that neutron-rich (Y {sub e} = 0.45-0.49) and proton-rich (Y {sub e} = 0.51-0.55) matter can increase Zn/Fe and Co/Fe ratios as observed, but tend to overproduce other Fe-peak elements. In addition, we find that if slightly proton-rich matter with 0.50 {<=} Y {sub e} < 0.501 with s/k {sub b} {approx} 15-40 is ejected as much as {approx}0.06 M {sub sun}, even normal SNe can reproduce the abundance of EMP stars, though it requires fine-tuning of Y {sub e}. On the other hand, HNe can more easily reproduce the observations of EMP stars without fine-tuning. Our results imply that HNe are the most likely origin of the abundance pattern of EMP stars.

  8. Carbon formation and metal dusting in hot-gas cleanup systems of coal gasifiers

    SciTech Connect

    Tortorelli, P.F.; DeVan, H.J.; Judkins, R.R.

    1995-06-01

    The product gas resulting from the partial oxidation of carboniferous materials in a gasifier consists predominantly of CO, CO{sub 2}, H{sub 2}, H{sub 2}O, CH{sub 4}, and, for air-blown units, N{sub 2} in various proportions at temperatures ranging from about 400 to 1000{degree}C. Depending on the source of the fuel, smaller concentrations of H{sub 2}S, COS, and NH{sub 3} can also be present. The gas phase is typically characterized by high carbon and sulfur, but low oxygen, activities and, consequently, severe degradation of the structural and functional materials used in the gasifier can occur. Therefore, there are numerous concerns about materials performance in coal gasification systems, particularly at the present time when demonstration-scale projects are in or nearing the construction and operation phases. This study focused on the subset of materials degradation phenomena resulting from carbon formation and carburization processes, which are related to potential operating problems in certain gasification components and subsystems. More specifically, it examined the current state of knowledge regarding carbon deposition and a carbon-related degradation phemonenon known as metal dusting as they affect the long-term operation of the gas clean-up equipment downstream of the gasifier and addressed possible means to mitigate the degradation processes. These effects would be primarily associated with the filtering and cooling of coal-derived fuel gases from the gasifier exit temperature to as low as 400{degree}C. However, some of the consideratins are sufficiently general to cover conditions relevant to other parts of gasification systems.

  9. Trap state passivation improved hot-carrier instability by zirconium-doping in hafnium oxide in a nanoscale n-metal-oxide semiconductor-field effect transistors with high-k/metal gate

    NASA Astrophysics Data System (ADS)

    Liu, Hsi-Wen; Chang, Ting-Chang; Tsai, Jyun-Yu; Chen, Ching-En; Liu, Kuan-Ju; Lu, Ying-Hsin; Lin, Chien-Yu; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Ye, Yi-Han

    2016-04-01

    This work investigates the effect on hot carrier degradation (HCD) of doping zirconium into the hafnium oxide high-k layer in the nanoscale high-k/metal gate n-channel metal-oxide-semiconductor field-effect-transistors. Previous n-metal-oxide semiconductor-field effect transistor studies demonstrated that zirconium-doped hafnium oxide reduces charge trapping and improves positive bias temperature instability. In this work, a clear reduction in HCD is observed with zirconium-doped hafnium oxide because channel hot electron (CHE) trapping in pre-existing high-k bulk defects is the main degradation mechanism. However, this reduced HCD became ineffective at ultra-low temperature, since CHE traps in the deeper bulk defects at ultra-low temperature, while zirconium-doping only passivates shallow bulk defects.

  10. Measurement of the thermal conductivity of KNO3-NaNO3 mixtures using a transient hot-wire method with a liquid metal in a capillary probe

    NASA Astrophysics Data System (ADS)

    Omotani, T.; Nagasaka, Y.; Nagashima, A.

    1982-03-01

    The thermal conductivity of KNO3-NaNO3 mixtures was measured by a modified transient hot-wire method using liquid metal in a capillary as a heat source. The method was developed for measurements on electrically conducting liquids at high temperatures. Measurements were performed on pure NaNO3 and its three mixtures with KNO3 in the temperature range from 498 to 593 K.

  11. Plasmon Mapping in Metallic Nanostructures and its Application to Single Molecule Surface Enhanced Raman Scattering: Imaging Electromagnetic Hot-Spots and Analyte Location

    SciTech Connect

    Camden, Jon P

    2013-07-16

    A major component of this proposal is to elucidate the connection between optical and electron excitation of plasmon modes in metallic nanostructures. These accomplishments are reported: developed a routine protocol for obtaining spatially resolved, low energy EELS spectra, and resonance Rayleigh scattering spectra from the same nanostructures.; correlated optical scattering spectra and plasmon maps obtained using STEM/EELS.; and imaged electromagnetic hot spots responsible for single-molecule surface-enhanced Raman scattering (SMSERS).

  12. An optical transmission spectrum of the transiting hot Jupiter in the metal-poor WASP-98 planetary system

    NASA Astrophysics Data System (ADS)

    Mancini, L.; Giordano, M.; Mollière, P.; Southworth, J.; Brahm, R.; Ciceri, S.; Henning, Th.

    2016-09-01

    The WASP-98 planetary system represents a rare case of a hot Jupiter hosted by a metal-poor main-sequence star. We present a follow-up study of this system based on multiband photometry and high-resolution spectroscopy. Two new transit events of WASP-98 b were simultaneously observed in four passbands (g', r', i', z'), using the telescope-defocusing technique, yielding eight high-precision light curves with point-to-point scatters of less than 1 mmag. We also collected three spectra of the parent star with a high-resolution spectrograph, which we used to remeasure its spectral characteristics, in particular its metallicity. We found this to be very low, [Fe/H] = -0.49 ± 0.10, but larger than was previously reported, [Fe/H] = -0.60 ± 0.19. We used these new photometric and spectroscopic data to refine the orbital and physical properties of this planetary system, finding that the stellar and planetary mass measurements are significantly larger than those in the discovery paper. In addition, the multiband light curves were used to construct an optical transmission spectrum of WASP-98 b and probe the characteristics of its atmosphere at the terminator. We measured a lower radius at z' compared with the other three passbands. The maximum variation is between the r' and z' bands, has a confidence level of roughly 6σ and equates to 5.5 pressure scale heights. We compared this spectrum to theoretical models, investigating several possible types of atmospheres, including hazy, cloudy, cloud-free, and clear atmospheres with titanium and vanadium oxide opacities. We could not find a good fit to the observations, except in the extreme case of a clear atmosphere with TiO and VO opacities, in which the condensation of Ti and V was suppressed. As this case is unrealistic, our results suggest the presence of an additional optical-absorbing species in the atmosphere of WASP-98 b, of unknown chemical nature.

  13. Detection of hot, metal-enriched outflowing gas around z ≈ 2.3 star-forming galaxies in the Keck Baryonic Structure Survey

    NASA Astrophysics Data System (ADS)

    Turner, Monica L.; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison L.

    2015-06-01

    We use quasar absorption lines to study the physical conditions in the circumgalactic medium of redshift z ≈ 2.3 star-forming galaxies taken from the Keck Baryonic Structure Survey. In Turner et al. we used the pixel optical depth technique to show that absorption by H I and the metal ions O VI, N V, C IV, C III, and Si IV is strongly enhanced within |Δv| ≲ 170 km s-1 and projected distances |d| ≲ 180 proper kpc from sightlines to the background quasars. Here we demonstrate that the O VI absorption is also strongly enhanced at fixed H I, C IV, and Si IV optical depths, and that this enhancement extends out to ˜350 km s-1. At fixed H I the increase in the median O VI optical depth near galaxies is 0.3-0.7 dex and is detected at 2-3σ confidence for all seven H I bins that have log _{10}τ_{H I} ≥ -1.5. We use ionization models to show that the observed strength of O VI as a function of H I is consistent with enriched, photoionized gas for pixels with τ_{H I} ≳ 10. However, for pixels with τ_{H I} ≲ 1 this would lead to implausibly high metallicities at low densities if the gas were photoionized by the background radiation. This indicates that the galaxies are surrounded by gas that is sufficiently hot to be collisionally ionized (T > 105 K) and that a substantial fraction of the hot gas has a metallicity ≳10-1 of solar. Given the high metallicity and large velocity extent (out to ˜1.5 vcirc) of this gas, we conclude that we have detected hot, metal-enriched outflows arising from star-forming galaxies.

  14. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  15. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  16. IR Hot Wave

    SciTech Connect

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  17. Mass Transfer Behavior of Phosphorus from the Liquid Slag Phase to Solid 2CaO·SiO2 in the Multiphase Dephosphorization Slag

    NASA Astrophysics Data System (ADS)

    Xie, Senlin; Wang, Wanlin; Luo, Zhican; Huang, Daoyuan

    2016-06-01

    The mass transfer behavior of phosphorus in the multiphase dephosphorization slag at 1623 K (1350 °C) is investigated in this article by adding the reagent P2O5 powders into the CaO-FeOt-SiO2 slag saturated with a directly precipitated 2CaO·SiO2 phase. The results show that the phosphorus was first quickly dissolved and transferred from the liquid slag to the precipitated solid 2CaO·SiO2 particle; then it reacted with the solid 2CaO·SiO2 particle to form (2CaO·SiO2-3CaO·P2O5) solid solution at the edge of a large solid particle. The further diffusion of phosphorus from the formed (2CaO·SiO2-3CaO·P2O5) solid solution reaction layer into the core of the 2CaO·SiO2 particle is the limiting step during the enrichment-phosphorus process. It is observed that the enrichment-phosphorus process is changed when the amount of added P2O5 content is increased and the formed solid solution phase is torn and peeled off from the surface of the 2CaO·SiO2 particle. In addition, the study shows that the solid solution structure is changed and becomes more compacted with the addition of P2O5 content, leading to the increment of solid solution density.

  18. HAT-P-24b: AN INFLATED HOT JUPITER ON A 3.36 DAY PERIOD TRANSITING A HOT, METAL-POOR STAR

    SciTech Connect

    Kipping, D. M.; Bakos, G. A.; Hartman, J.; Torres, G.; Latham, D. W.; Noyes, R. W.; Beky, B.; Perumpilly, G.; Esquerdo, G. A.; Sasselov, D. D.; Stefanik, R. P.; Shporer, A.; Kovacs, Geza; Howard, A. W.; Marcy, G. W.; Fischer, D. A.; Johnson, J. A.; Lazar, J.; Papp, I.; Sari, P.

    2010-12-20

    We report the discovery of HAT-P-24b, a transiting extrasolar planet orbiting the moderately bright V = 11.818 F8 dwarf star GSC 0774-01441, with a period P = 3.3552464 {+-} 0.0000071 days, transit epoch T{sub c} = 2455216.97669 {+-} 0.00024 (BJD)11, and transit duration 3.653 {+-} 0.025 hr. The host star has a mass of 1.191 {+-} 0.042 M{sub sun}, radius of 1.317 {+-} 0.068 R{sub sun}, effective temperature 6373 {+-} 80 K, and a low metallicity of [Fe/H] = -0.16 {+-} 0.08. The planetary companion has a mass of 0.681 {+-} 0.031 M{sub J} and radius of 1.243 {+-} 0.072 R{sub J} yielding a mean density of 0.439 {+-} 0.069 g cm{sup -3}. By repeating our global fits with different parameter sets, we have performed a critical investigation of the fitting techniques used for previous Hungarian-made Automated Telescope planetary discoveries. We find that the system properties are robust against the choice of priors. The effects of fixed versus fitted limb darkening are also examined. HAT-P-24b probably maintains a small eccentricity of e = 0.052{sup +0.022}{sub -0.017}, which is accepted over the circular orbit model with false alarm probability 5.8%. In the absence of eccentricity pumping, this result suggests that HAT-P-24b experiences less tidal dissipation than Jupiter. Due to relatively rapid stellar rotation, we estimate that HAT-P-24b should exhibit one of the largest known Rossiter-McLaughlin effect amplitudes for an exoplanet ({Delta}V{sub RM} {approx_equal} 95 m s{sup -1}) and thus a precise measurement of the sky-projected spin-orbit alignment should be possible.

  19. Fiber optic hot-wire flowmeter based on a metallic coated hybrid long period grating/fiber Bragg grating structure.

    PubMed

    Caldas, Paulo; Jorge, Pedro A S; Rego, Gaspar; Frazão, Orlando; Santos, José Luís; Ferreira, Luís Alberto; Araújo, Francisco

    2011-06-10

    In this work an all-optical hot-wire flowmeter based on a silver coated fiber combining a long period grating and a fiber Bragg grating (FBG) structure is proposed. Light from a pump laser at 1480  nm propagating down the fiber is coupled by the long period grating into the fiber cladding and is absorbed by the silver coating deposited on the fiber surface over the Bragg grating structure. This absorption acts like a hot wire raising the fiber temperature locally, which is effectively detected by the FBG resonance shift. The temperature increase depends on the flow speed of the surrounding air, which has the effect of cooling the fiber. It is demonstrated that the Bragg wavelength shift can be related to the flow speed. A flow speed resolution of 0.08  m/s is achieved using this new configuration. PMID:21673779

  20. Effects of Non-metallic Inclusions on Hot Ductility of High Manganese TWIP Steels Containing Different Aluminum Contents

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Nan; Yang, Jian; Wang, Rui-Zhi; Xin, Xiu-Ling; Xu, Long-Yun

    2016-06-01

    The characteristics of inclusions in Fe-16Mn- xAl-0.6C ( x = 0.002, 0.033, 0.54, 2.10 mass pct) steels have been investigated and their effects on hot ductility of the high manganese TWIP steels have been discussed. Ductility is very poor in the steel containing 0.54 mass pct aluminum, which is lower than 20 pct in the temperature range of 873 K to 1473 K (600 °C to 1200 °C). For the steels containing 0.002 and 2.10 mass pct aluminum, ductility is higher than 40 pct in the same temperature range. The hot ductility of steel containing 0.033 mass pct aluminum is higher than 30 pct throughout the temperature range under examination. With increasing aluminum content, the main inclusions in the steels change along the route of MnO/(MnO + MnS) → MnS/(Al2O3 + MnS) → AlN/(Al2O3 + MnS)/(MgAl2O4 + MnS) → AlN. The thermodynamic results of inclusion types calculated with FactSage software are in agreement with the experimental observation results. The inclusions in the steels containing 0.002 mass pct aluminum do not deteriorate the hot ductility. MnS inclusions whose average size, number density, and volume ratio are 1.12 μm, 15.62 mm-2, and 2.51 × 10-6 in the steel containing 0.033 mass pct aluminum reduce the ductility. In the steel containing 0.54 mass pct aluminum, AlN inclusions whose average size, number density, and volume ratio are 0.878 μm, 16.28 mm-2 and 2.82 × 10-6 can precipitate at the austenite grain boundaries, prevent dynamic recrystallization and deteriorate the hot ductility. On the contrary, in the steel containing 2.10 mass pct aluminum, the average size, number density and volume ratio of AlN inclusions change to 2.418 μm, 35.95 mm-2, and 2.55 × 10-5. They precipitate in the matrix, which do not inhibit dynamic recrystallization and thereby do not lead to poor hot ductility.

  1. Investigation into the role of sodium chloride deposited on oxide and metal substrates in the initiation of hot corrosion

    NASA Technical Reports Server (NTRS)

    Birks, N.

    1983-01-01

    Sodium chloride is deposited on the surface of alumina substrates and exposed to air containing 1% SO2 at temperatures between 500 C and 700 C. In all cases the sodium chloride was converted to sodium sulfate. The volatilization of sodium chloride from the original salt particles was responsible for the development of a uniform coating of sodium sulfate on the alumina substrate. At temperatures above 625 C, a liquid NaCl-Na2SO4 autectic was formed on the substrate. The mechanisms for these reactions are given. One of the main roles of NaCl in low temperature hot corrosion lies in enabling a corrosive liquid to form.

  2. Fabrication and Analysis of the Wear Properties of Hot-Pressed Al-Si/SiCp + Al-Si-Cu-Mg Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Bang, Jeongil; Oak, Jeong-Jung; Park, Yong Ho

    2016-01-01

    The aim of this study was to characterize microstructures and mechanical properties of aluminum metal matrix composites (MMC's) prepared by powder metallurgy method. Consolidation of mixed powder with gas atomized Al-Si/SiCp powder and Al-14Si-2.5Cu-0.5Mg powder by hot pressing was classified according to sintering temperature and sintering time. Sintering condition was optimized using tensile properties of sintered specimens. Ultimate tensile strength of the optimized sintered specimen was 228 MPa with an elongation of 5.3% in longitudinal direction. In addition, wear properties and behaviors of the sintered aluminum-based MMC's were analyzed in accordance with vertical load and linear speed. As the linear speed and vertical load of the wear increased, change of the wear behavior occurred in order of oxidation of Al-Si matrix, formation of C-rich layer, Fe-alloying to matrix, and melting of the specimen

  3. Photon Doppler Velocimeter to Measure Entrained Additive Manufactured Bulk Metal Powders in Hot Subsonic and Supersonic Oxygen Gas

    NASA Technical Reports Server (NTRS)

    Tylka, Jonathan

    2016-01-01

    Parts produced by additive manufacturing, particularly selective laser melting (SLM), have been shown to silt metal particulate even after undergoing stringent precision aerospace cleaning processes (Lowrey 2016). As printed parts are used in oxygen systems with increased pressures, temperatures, and gas velocity, the risk of ignition by particle impact, the most common direct ignition source of metals in oxygen, substantially increases. The White Sands Test Facility (WSTF), in collaboration with Marshall Space Flight Center (MSFC), desires to test the ignitability of SLM metals by particle impact in heated oxygen. The existing test systems rely on gas velocity calculations to infer particle velocity in both subsonic and supersonic particle impact systems. Until now, it was not possible to directly measure particle velocity. To increase the fidelity of planned SLM ignition studies, it is necessary to validate that the Photon Doppler Velocimetry(PDV) test system can accurately measure particle velocity.

  4. Designing the Color of Hot-Dip Galvanized Steel Sheet Through Destructive Light Interference Using a Zn-Ti Liquid Metallic Bath

    NASA Astrophysics Data System (ADS)

    Levai, Gabor; Godzsák, Melinda; Török, Tamas I.; Hakl, Jozsef; Takáts, Viktor; Csik, Attila; Vad, Kalman; Kaptay, George

    2016-07-01

    The color of hot-dip galvanized steel sheet was adjusted in a reproducible way using a liquid Zn-Ti metallic bath, air atmosphere, and controlling the bath temperature as the only experimental parameter. Coloring was found only for samples cooled in air and dipped into Ti-containing liquid Zn. For samples dipped into a 0.15 wt pct Ti-containing Zn bath, the color remained metallic (gray) below a 792 K (519 °C) bath temperature; it was yellow at 814 K ± 22 K (541 °C ± 22 °C), violet at 847 K ± 10 K (574 °C ± 10 °C), and blue at 873 K ± 15 K (600 °C ± 15 °C). With the increasing bath temperature, the thickness of the adhered Zn-Ti layer gradually decreased from 52 to 32 micrometers, while the thickness of the outer TiO2 layer gradually increased from 24 to 69 nm. Due to small Al contamination of the Zn bath, a thin (around 2 nm) alumina-rich layer is found between the outer TiO2 layer and the inner macroscopic Zn layer. It is proven that the color change was governed by the formation of thin outer TiO2 layer; different colors appear depending on the thickness of this layer, mostly due to the destructive interference of visible light on this transparent nano-layer. A complex model was built to explain the results using known relationships of chemical thermodynamics, adhesion, heat flow, kinetics of chemical reactions, diffusion, and optics. The complex model was able to reproduce the observations and allowed making predictions on the color of the hot-dip galvanized steel sample, as a function of the following experimental parameters: temperature and Ti content of the Zn bath, oxygen content, pressure, temperature and flow rate of the cooling gas, dimensions of the steel sheet, velocity of dipping the steel sheet into the Zn-Ti bath, residence time of the steel sheet within the bath, and the velocity of its removal from the bath. These relationships will be valuable for planning further experiments and technologies on color hot-dip galvanization of steel

  5. Experimental and Numerical Analysis on the Distortion of Parts Made of 20MnCr5 by Hot Metal Forming

    SciTech Connect

    Rentsch, Ruediger; Brinksmeier, Ekkard

    2011-05-04

    For high performance applications, shafts and gears made of 20MnCr5 (AISI 5120) are manufactured in large numbers every year. Inhomogeneities in the material properties, process perturbations and asymmetries in shape and operation setups provide a potential for the distortion of parts, often released by heat treatment. In this contribution experimental results on the distortion of shafts and the dishing of disk-like gear wheel blanks are presented. The numerical analysis of the hot-rolling process allowed to trace a peculiar segregation distribution at the cross-section of the bars back to the casting process, and to identify an asymmetric strain distribution which may be the main cause for shaft distortion. For the dishing of the disks a correlation to the resulting distribution of the material flow was found and, a process perturbation parameter identified which is assumed to be responsible for the observed material flow variation.

  6. Theoretical Modelling of Hot Stars

    NASA Astrophysics Data System (ADS)

    Najarro, F.; Hillier, D. J.; Figer, D. F.; Geballe, T. R.

    1999-06-01

    Recent progress towards model atmospheres for hot stars is discussed. A new generation of NLTE wind blanketed models, together with high S/N spectra of the hot star population in the central parsec, which are currently being obtained, will allow metal abundance determinations (Fe, Si, Mg, Na, etc). Metallicity studies of hot stars in the IR will provide major constraints not only on the theory of evolution of massive stars but also on our efforts to solve the puzzle of the central parsecs of the Galaxy. Preliminary results suggest that the metallicity of the Pistol Star is 3 times solar, thus indicating strong chemical enrichment of the gas in the Galactic Center.

  7. Investigation into the role of NaCL deposited on oxide and metal substrates in the initiation of hot corrosion

    NASA Technical Reports Server (NTRS)

    Birks, N.

    1981-01-01

    The conversion to Na2SO4 of NaCl deposited on oxide substrates was studied as a function of temperature, in air with various SO2 and H2O partial pressures. The substrate was either a pure oxide or an oxide scale growing on a metal specimen. The progress of the reaction was observed using the SEM-EDAX technique to monitor morphological effects and, as far as possible, establish the rate of the process. The physical characteristics of the interaction between salt and substrate were also examined with particular reference to physical damage to the underlying oxide, especially when this is a scale on a metal specimen. An effort was also made to establish the conditions under which liquid phases may form and the mechanisms by which they form.

  8. Trapping in GaN-based metal-insulator-semiconductor transistors: Role of high drain bias and hot electrons

    SciTech Connect

    Meneghini, M. Bisi, D.; Meneghesso, G.; Zanoni, E.

    2014-04-07

    This paper describes an extensive analysis of the role of off-state and semi-on state bias in inducing the trapping in GaN-based power High Electron Mobility Transistors. The study is based on combined pulsed characterization and on-resistance transient measurements. We demonstrate that—by changing the quiescent bias point from the off-state to the semi-on state—it is possible to separately analyze two relevant trapping mechanisms: (i) the trapping of electrons in the gate-drain access region, activated by the exposure to high drain bias in the off-state; (ii) the trapping of hot-electrons within the AlGaN barrier or the gate insulator, which occurs when the devices are operated in the semi-on state. The dependence of these two mechanisms on the bias conditions and on temperature, and the properties (activation energy and cross section) of the related traps are described in the text.

  9. Method for producing metallic nanoparticles

    DOEpatents

    Phillips, Jonathan; Perry, William L.; Kroenke, William J.

    2004-02-10

    Method for producing metallic nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating non-oxidizing plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone to metal vapor. The metal vapor is directed away from the hot zone and to the plasma afterglow where it cools and condenses to form solid metallic nanoparticles.

  10. Hot Groups.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    Collaborators sparked by creative ideas and obsessed by a common task may not realize they're part of a "hot group"--a term coined by business professors Harold J. Leavitt and Jean Lipman-Blumen. Spawned by group decision making and employee empowerment, hot groups can flourish in education settings. They're typically small, short lived, and goal…

  11. HATS-11b AND HATS-12b: Two Transiting Hot Jupiters Orbiting Subsolar Metallicity Stars Selected for the K2 Campaign 7

    NASA Astrophysics Data System (ADS)

    Rabus, M.; Jordán, A.; Hartman, J. D.; Bakos, G. Á.; Espinoza, N.; Brahm, R.; Penev, K.; Ciceri, S.; Zhou, G.; Bayliss, D.; Mancini, L.; Bhatti, W.; de Val-Borro, M.; Csbury, Z.; Sato, B.; Tan, T.-G.; Henning, T.; Schmidt, B.; Bento, J.; Suc, V.; Noyes, R.; Lázár, J.; Papp, I.; Sári, P.

    2016-10-01

    We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V = 14.1 G0-star shows a periodic 12.9 mmag dip in its light curve every 3.6192 days and a radial velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of 1.000+/- 0.060 {M}⊙ , a radius of 1.444+/- 0.057 {R}⊙ and an effective temperature of 6060+/- 150 K, while its companion is a 0.85+/- 0.12 {M}{{J}}, 1.510+/- 0.078 {R}{{J}} planet in a circular orbit. HATS-12 shows a periodic 5.1 mmag flux decrease every 3.1428 days and Keplerian RV variations around a V = 12.8 F-star. HATS-12 has a mass of 1.489+/- 0.071 {M}⊙ , a radius of 2.21+/- 0.21 {R}⊙ , and an effective temperature of 6408+/- 75 K. For HATS-12b, our measurements indicate that this is a 2.38+/- 0.11 {M}{{J}}, 1.35+/- 0.17 {R}{{J}} planet in a circular orbit. Both host stars show subsolar metallicities of -0.390+/- 0.060 dex and -0.100+/- 0.040 dex, respectively, and are (slightly) evolved stars. In fact, HATS-11 is among the most metal-poor and, HATS-12, with a {log}{g}\\star of 3.923+/- 0.065, is among the most evolved stars hosting a hot-Jupiter planet. Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively). The HATSouth network is operated by a collaboration consisting of Princeton University (PU), the Max Planck Institute für Astronomie (MPIA), the Australian National University (ANU), and the Pontificia Universidad Católica de Chile (PUC). The station at Las Campanas Observatory (LCO) of the Carnegie Institute is operated by PU in conjunction with PUC, the station at the High Energy Spectroscopic Survey (H.E.S.S.) site is operated in conjunction with MPIA, and the station at Siding Spring Observatory (SSO) is operated jointly with ANU. Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Based in part on

  12. A numerical study on the use of liquid metals (gallium and mercury) as agents to enhance heat transfer from hot water in a co-flow mini-channel system

    NASA Astrophysics Data System (ADS)

    Al Omari, S.-A. B.

    2012-10-01

    Enhancement in the heat removal from hot water co-flowing in a mini-channel in a direct contact manner with two liquid metals, gallium and mercury, is investigated numerically. Results show that the liquid metals lead to superior heat removal from hot water co-flowing in the channel as compared to the case when only water flows in the channel. Moreover, it is found that gallium yields higher heat removal from water than mercury by about 15 %. This percentage, representing the superiority of gallium over mercury increases to about 20 % under conditions when the mass flow rate of both the liquid metal and the co-flowing water are doubled. The results reported showed numerical mesh independence. However, the results show much dependence on the spatial discretization scheme adopted where it is found that first order upwind scheme yields somewhat over predicted heat exchange rates in the channel, as compared with the case when a second order scheme is used. It is found further that the channel efficiency in removing heat from the water is remarkable in the first half of the overall channel length where in general the heat removed in the first 10 mm of the channel length is found to be about 70 % of the total heat removed. This percentage is a bit less than that when only water flows in the channel.

  13. Hot Canyon

    ScienceCinema

    None

    2016-07-12

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  14. Hot Canyon

    SciTech Connect

    2012-01-01

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  15. Hot Tickets

    ERIC Educational Resources Information Center

    Fox, Bette-Lee; Hoffert, Barbara; Kuzyk, Raya; McCormack, Heather; Williams, Wilda

    2008-01-01

    This article describes the highlights of this year's BookExpo America (BEA) held at the Los Angeles Convention Center. The attendees at BEA had not minded that the air was recycled, the lighting was fluorescent, and the food was bad. The first hot book sighting came courtesy of Anne Rice. Michelle Moran, author of newly published novel, "The…

  16. Hot tearing evaluation for aluminium alloys

    NASA Astrophysics Data System (ADS)

    Brůna, Marek

    2016-06-01

    Hot tearing during solidification of aluminium alloys castings can be a serious problem. This phenomenon is well known but still insufficiently investigated. Hot tearing occurs in form of irregular cracks in metal castings that develop during solidification and cooling. The cause of hot tearing is generally attributed to the development of thermally induced tensile stresses and strains in a casting as the molten metal contracts during solidification and solid state shrinkage. Submited paper consists of two parts. The first part introduces the reader to the phenomenon of hot tearing. The second part describes newly developed method for assessing hot tearing susceptibility of aluminium alloys, and also gives the results on hot tearing for various aluminium alloys.

  17. Hot outflows in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, C. C.; McNamara, B. R.

    2015-10-01

    The gas-phase metallicity distribution has been analysed for the hot atmospheres of 29 galaxy clusters using Chandra X-ray Observatory observations. All host brightest cluster galaxies (BCGs) with X-ray cavity systems produced by radio AGN. We find high elemental abundances projected preferentially along the cavities of 16 clusters. The metal-rich plasma was apparently lifted out of the BCGs with the rising X-ray cavities (bubbles) to altitudes between twenty and several hundred kiloparsecs. A relationship between the maximum projected altitude of the uplifted gas (the `iron radius') and jet power is found with the form R_Fe ∝ P_jet^{0.45}. The estimated outflow rates are typically tens of solar masses per year but exceed 100 M⊙ yr- 1 in the most powerful AGN. The outflow rates are 10-20 per cent of the cooling rates, and thus alone are unable to offset a cooling inflow. Nevertheless, hot outflows effectively redistribute the cooling gas and may play a significant role at regulating star formation and AGN activity in BCGs and presumably in giant elliptical galaxies. The metallicity distribution overall can be complex, perhaps due to metal-rich gas returning in circulation flows or being blown around in the hot atmospheres. Roughly 15 per cent of the work done by the cavities is expended lifting the metal-enriched gas, implying their nuclear black holes have increased in mass by at least ˜107-109 M⊙. Finally, we show that hot outflows can account for the broad, gas-phase metallicity distribution compared to the stellar light profiles of BCGs, and we consider a possible connection between hot outflows and cold molecular gas flows discovered in recent Atacama Large Millimeter Array observations.

  18. Influence of Hot Carrier Transport on the Transient Response of an InGaAs/InAlAs Metal-Semiconductor Schottky Diode Structure

    NASA Technical Reports Server (NTRS)

    Salem, Ali F.; Brennan, Kevin F.

    1996-01-01

    The calculated transient characteristic of a heterostructure, rectifying contact is theoretically examined. It is found that hot carrier transport drastically affects the output terminal characteristics of the heterostructure Schottky contact and, hence, the working of a blocking contact. This is of importance to the understanding of InGaAs MSM devices in particular, as well as any structure which contains a blocking contact in general.

  19. Hot Meetings

    NASA Technical Reports Server (NTRS)

    Chiu, Mary

    2002-01-01

    A colleague walked by my office one time as I was conducting a meeting. There were about five or six members of my team present. The colleague, a man who had been with our institution (The Johns Hopkins Applied Physics Lab, a.k.a. APL) for many years, could not help eavesdropping. He said later it sounded like we we re having a raucous argument, and he wondered whether he should stand by the door in case things got out of hand and someone threw a punch. Our Advanced Composition Explorer (ACE) team was a hot group, to invoke the language that is fashionable today, although we never thought of ourselves in those terms. It was just our modus operandi. The tenor of the discussion got loud and volatile at times, but I prefer to think of it as animated, robust, or just plain collaborative. Mary Chiu and her "hot" team from the Johns Hopkins Applied Physics Laboratory built the Advanced Composition Explorer spacecraft for NASA. Instruments on the spacecraft continue to collect data that inform us about what's happening on our most important star, the Sun.

  20. Major ions anomalies and contamination status by trace metals in sediments from two hot spots along the Mediterranean Coast of Egypt.

    PubMed

    Shreadah, Mohamed A; Shobier, Aida H; Ghani, Safaa A Abdel; El Zokm, Gehan M; Said, Tarek O

    2015-05-01

    The major constituents and trace metals in the surface sediments collected from the Western Harbor and El-Mex Bay along the Egyptian Mediterranean Coast were studied. The concentrations of major constituents decreased in the following order: Ca > Si > Mg > Na > K for the Western Harbor and El-Mex Bay. Additionally, the ranking order of trace metals was Fe > Al > Pb > Zn > Mn > Cu > Sn > V > As > Cd > Se for the Western Harbor. For El-Mex Bay, the decreasing order was Fe > Al > Mn > Sn > Pb > Zn > Cu > V > As > Cd > Se. Fe, Al, Zn, Pb, Cu, V, Cd and Sn in the Western Harbor occurred in higher concentrations than in El-Mex Bay. A higher concentration of Mn was observed in El-Mex Bay. Two pollution indicators, enrichment factor (EF) and metal pollution index (MPI), and several sediment quality guidelines (SQGs) were used to evaluate the status of metal pollution. Based on the mean EF values of the studied metals, surface sediments of the Western Harbor and El-Mex Bay revealed that they are enriched with metals from anthropogenic sources. An analysis of variance (ANOVA) test showed that the mean measurements for all metals across the Western Harbor and El-Mex Bay are significantly different at a 0.05 significance level. Principal components analysis (PCA) was applied in result interpretation. The spatial distribution of the different parameters was illustrated.

  1. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  2. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  3. Advanced hot gas filter development

    SciTech Connect

    McMahon, T.J.

    1998-12-31

    Advanced coal-based power generation systems require hot gas cleanup under high-temperature, high-pressure process conditions in order to realize high efficiency and superior environmental performance. A key component of Integrated Gasification Combined Cycle and Pressurized Fluidized Bed Combustion systems is the hot gas filtration system, which removes particulate matter from the gas stream before it enters the gas turbine. The US DOE is currently sponsoring a program to develop and test hot gas filtration systems, demonstrating their reliability and commercial readiness. Reliability of individual filter elements is a major factor in determining the overall system reliability, and testing has shown that conventional ceramic filter elements are subject to brittle failure and thermal stress damage. In order to increase filter element reliability, a program was initiated to develop ceramic and metal filter elements resistant to brittle failure and thermal stress damage. Filter elements have been developed using advanced materials including continuous fiber ceramic composites, other novel ceramics, and corrosion resistant metals. The general approach taken under this program has been to first develop porous filter media from advanced materials that meet permeability and strength requirements, followed by fabrication of porous media into full scale filter elements. Filter elements and filter media were subjected to laboratory scale corrosion and filtration testing. Filter elements successfully passing laboratory testing have been tested under pilot scale conditions. This paper will summarize the development and testing of these advanced hot gas filters.

  4. Are hot Neptunes partially evaporated hot Jupiters?

    NASA Astrophysics Data System (ADS)

    Boué, G.; Figueira, P.; Correia, A. C. M.; Santos, N. C.

    2011-10-01

    The detection of short period planets (hot Jupiters and their lower mass counterparts, hot Neptunes and super-Earths) still defies the models of planet formation and evolution. Several possibilities have been proposed to explain the nature and formation process of the lower mass population, including in situ formation, disk migration, planet-planet scattering and kozai evolution, and the evaporation of a higher mass hot Jupiter. Using dynamical models and the best estimates for evaporation velocities, we show that under reasonable (and observed) physical conditions, hot Jupiter evaporation may explain the observed population of hot Neptunes/super-Earths.

  5. Are Hot Neptunes Partialy Evaporated Hot Jupiters?

    NASA Astrophysics Data System (ADS)

    Santos, Nuno; Boue, G.; Figueira, P.; Correia, A.

    2011-09-01

    The detection of short period planets (hot Jupiters and their lower mass counterparts, hot neptunes and super-earths) still defies the models of planet formation and evolution. Several possibilities have been proposed to explain the nature and formation process of the lower mass population, including in situ formation, disk migration, planet-planet scattering and kozai evolution, and the evaporation of a higher mass hot Jupiter. Using dynamical models and the best estimates for evaporation velocities, we show that under reasonable (and observed) physical conditions, hot Jupiter evaporation can explain the observed population of hot Neptunes/super-Earths.

  6. The Phosphorus Reaction in Oxygen Steelmaking: Thermodynamic Equilibrium and Metal Droplet Behavior

    NASA Astrophysics Data System (ADS)

    Assis, Andre N.

    Phosphorus equilibrium between liquid metal and slag has been extensively studied since the 1940's. It is well known that CaO and FeO are the main slag constituents that help promote dephosphorization. On the other hand, dephosphorization decreases with temperature due to the endothermic nature of the reaction. Many correlations have been developed to predict the phosphorus partition ratio as a function of metal and slag composition as well as temperature. Nevertheless, there are still disagreements in the laboratory data and the equilibrium phosphorus partition can be predicted with an uncertainty of a factor of up to 5. The first part of the present work focuses on generating more reliable equilibrium data for BOF-type slags by approaching equilibrium from both sides of the reaction. The experimental results were combined with two other sets of data from different authors to produce a new correlation that includes the effect of SiO2 on the phosphorus partition coefficient, LP . Although the quantification of phosphorus equilibrium is extremely important, most industrial furnaces do not operate at equilibrium, usually due to liquid slag formation, kinetics and time constraints. Thus, it is important to know how close to equilibrium different furnaces operate in order to suggest optimal slag compositions to promote dephosphorization. The present work analyzed four large sets of data containing the chemical compositions of both slag and metal phase as well as the tapping temperature of each heat. Each set of data corresponded to different furnaces: one AOD (Argon Oxygen Decarburization), two top-blown BOFs and one Q-BOP or OBM. It was found that the bulk slag composition can greatly "mask" the data due to solid phases coexisting with the liquid slag. The author used the software package FactSage to estimate the amount of solids in the slag and liquid slag composition. It was found that the AOD is the reactor closest to equilibrium, followed by the Q-BOP (OBM) and

  7. Anomalous ultrafast dynamics of hot plasmonic electrons in nanostructures with hot spots.

    PubMed

    Harutyunyan, Hayk; Martinson, Alex B F; Rosenmann, Daniel; Khorashad, Larousse Khosravi; Besteiro, Lucas V; Govorov, Alexander O; Wiederrecht, Gary P

    2015-09-01

    The interaction of light and matter in metallic nanosystems is mediated by the collective oscillation of surface electrons, called plasmons. After excitation, plasmons are absorbed by the metal electrons through inter- and intraband transitions, creating a highly non-thermal distribution of electrons. The electron population then decays through electron-electron interactions, creating a hot electron distribution within a few hundred femtoseconds, followed by a further relaxation via electron-phonon scattering on the timescale of a few picoseconds. In the spectral domain, hot plasmonic electrons induce changes to the plasmonic resonance of the nanostructure by modifying the dielectric constant of the metal. Here, we report on the observation of anomalously strong changes to the ultrafast temporal and spectral responses of these excited hot plasmonic electrons in hybrid metal/oxide nanostructures as a result of varying the geometry and composition of the nanostructure and the excitation wavelength. In particular, we show a large ultrafast, pulsewidth-limited contribution to the excited electron decay signal in hybrid nanostructures containing hot spots. The intensity of this contribution correlates with the efficiency of the generation of highly excited surface electrons. Using theoretical models, we attribute this effect to the generation of hot plasmonic electrons from hot spots. We then develop general principles to enhance the generation of energetic electrons through specifically designed plasmonic nanostructures that could be used in applications where hot electron generation is beneficial, such as in solar photocatalysis, photodetectors and nonlinear devices.

  8. KELT-6b: A P ∼ 7.9 day hot Saturn transiting a metal-poor star with a long-period companion

    SciTech Connect

    Collins, Karen A.; Kielkopf, John F.; Eastman, Jason D.; Beatty, Thomas G.; Gaudi, B. Scott; Siverd, Robert J.; Pepper, Joshua; Stassun, Keivan G.; Johnson, John Asher; Howard, Andrew W.; Fulton, Benjamin J.; Fischer, Debra A.; Manner, Mark; Bieryla, Allyson; Latham, David W.; Gregorio, Joao; Buchhave, Lars A.; Jensen, Eric L. N.; Penev, Kaloyan; Crepp, Justin R.; and others

    2014-02-01

    We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T {sub eff} = 6102 ± 43 K, log g{sub ⋆}=4.07{sub −0.07}{sup +0.04}, and [Fe/H] = –0.28 ± 0.04, with an inferred mass M {sub *} = 1.09 ± 0.04 M {sub ☉} and radius R{sub ⋆}=1.58{sub −0.09}{sup +0.16} R{sub ⊙}. The planetary companion has mass M{sub P} = 0.43 ± 0.05 M {sub Jup}, radius R{sub P}=1.19{sub −0.08}{sup +0.13} R{sub Jup}, surface gravity log g{sub P}=2.86{sub −0.08}{sup +0.06}, and density ρ{sub P}=0.31{sub −0.08}{sup +0.07} g cm{sup −3}. The planet is on an orbit with semimajor axis a = 0.079 ± 0.001 AU and eccentricity e=0.22{sub −0.10}{sup +0.12}, which is roughly consistent with circular, and has ephemeris of T {sub c}(BJD{sub TDB}) = 2456347.79679 ± 0.00036 and P = 7.845631 ± 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by ∼4)-7). KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by ∼0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images.

  9. Method for producing metal oxide nanoparticles

    DOEpatents

    Phillips, Jonathan; Mendoza, Daniel; Chen, Chun-Ku

    2008-04-15

    Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

  10. Hot Subluminous Stars

    NASA Astrophysics Data System (ADS)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  11. Hot Subluminous Stars

    NASA Astrophysics Data System (ADS)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung–Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  12. Secondary precious metal enrichment by steam-heated fluids in the Crofoot-Lewis hot spring gold-silver deposit and relation to paleoclimate

    USGS Publications Warehouse

    Ebert, S.W.; Rye, R.O.

    1997-01-01

    controlled largely by basin and range fractures and a high geothermal gradient with H2S for Au complexing derived from organic matter in basin sediments. A wet climate resulted in the formation of a large inland lake which provided abundant recharge water for the hydrothermal system. A fluctuating water table controlled by changing climatic conditions enabled steam-heated acid sulfate fluids to overprint lower grade mineralization resulting in ore-grade precious metal enrichment.

  13. Hierarchical Simulation of Hot Composite Structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Murthy, P. L. N.; Singhal, S. N.

    1993-01-01

    Computational procedures are described to simulate the thermal and mechanical behavior of high temperature metal matrix composites (HT-MMC) in the following three broad areas: (1) Behavior of HT-MMC's from micromechanics to laminate via Metal Matrix Composite Analyzer (METCAN), (2) tailoring of HT-MMC behavior for optimum specific performance via Metal Matrix Laminate Tailoring (MMLT), and (3) HT-MMC structural response for hot structural components via High Temperature Composite Analyzer (HITCAN). Representative results from each area are presented to illustrate the effectiveness of computational simulation procedures. The sample case results show that METCAN can be used to simulate material behavior such as strength, stress-strain response, and cyclic life in HTMMC's; MMLT can be used to tailor the fabrication process for optimum performance such as that for in-service load carrying capacity of HT-MMC's; and HITCAN can be used to evaluate static fracture and fatigue life of hot pressurized metal matrix composite rings.

  14. Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14CR15Y2C15B6 and Variants

    SciTech Connect

    Farmer, J; Haslam, J; Day, S; Lian, T; Saw, C; Hailey, P; Choi, J; Yang, N; Blue, C; Peter, W; Payer, J; Perepezko, J; Hildal, K; Branagan, D J; Beardsley, M B; Aprigliano, L

    2006-10-12

    The passive film stability of several Fe-based amorphous metal formulations have been found to be comparable to that of stainless steels and Ni-based Alloy C-22 (UNS No. N06022), based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. Electrochemical studies of the passive film stability of SAM1651 are reported here. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). Yttrium-containing SAM1651, also known as SAM7 (Fe{sub 48.0}Cr{sub 15.0}Mo{sub 14.0}B{sub 6.0}C{sub 15.0}Y{sub 2.0}), has a critical cooling rate (CCR) of approximately 80 Kelvin per second, while yttrium-free SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) has a higher critical cooling rate of approximately 600 Kelvin per second. SAM1651's low CCR enables it to be rendered as a completely amorphous material in practical materials processes. While the yttrium enables a low CCR to be achieved, it makes the material relatively difficult to atomize, due to increases in melt viscosity. Consequently, the powders have irregular shape, which makes pneumatic conveyance during thermal spray deposition difficult. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer or inhibitor. SAM1651 may also experience crevice corrosion under sufficiently harsh conditions. Both Alloy C-22 and Type 316L stainless lose their resistance to corrosion during thermal spraying, due to the formation of deleterious intermetallic phases which depletes the matrix of key alloy elements, whereas SAM1651 can be applied as coatings with the same corrosion resistance as a fully-dense completely amorphous melt-spun ribbon, provided that its amorphous

  15. Solutions for Hot Situations

    NASA Technical Reports Server (NTRS)

    2003-01-01

    From the company that brought the world an integral heating and cooling food service system after originally developing it for NASA's Apollo Program, comes yet another orbital offshoot: a product that can be as thin as paper and as strong as steel. Nextel Ceramic Textiles and Composites from 3M Company offer space-age protection and innovative solutions for hot situations, ranging from NASA to NASCAR. With superior thermal protection, Nextel fabrics, tape, and sleevings outperform other high temperature textiles such as aramids, carbon, glass, and quartz, permitting engineers and manufacturers to handle applications up to 2,500 F (1,371 C). The stiffness and strength of Nextel Continuous Ceramic Fibers make them a great match for improving the rigidity of aluminum in metal matrix composites. Moreover, the fibers demonstrate low shrinkage at operating temperatures, which allow for the manufacturing of a dimensionally stable product. These novel fibers also offer excellent chemical resistance, low thermal conductivity, thermal shock resistance, low porosity, and unique electrical properties.

  16. Method for producing metallic microparticles

    DOEpatents

    Phillips, Jonathan; Perry, William L.; Kroenke, William J.

    2004-06-29

    Method for producing metallic particles. The method converts metallic nanoparticles into larger, spherical metallic particles. An aerosol of solid metallic nanoparticles and a non-oxidizing plasma having a portion sufficiently hot to melt the nanoparticles are generated. The aerosol is directed into the plasma where the metallic nanoparticles melt, collide, join, and spheroidize. The molten spherical metallic particles are directed away from the plasma and enter the afterglow where they cool and solidify.

  17. A micromechanical switchable hot spot for SERS applications

    NASA Astrophysics Data System (ADS)

    Naumenko, Denys; Toffoli, Valeria; Greco, Silvio; Dal Zilio, Simone; Bek, Alpan; Lazzarino, Marco

    2016-09-01

    Hot spots are defined as nanostructures of noble metal able to locally enhance the electromagnetic field of several orders of magnitude and to confine this effect to a region for several orders of magnitude smaller than the light wavelength. Hot spots are particularly important for the surface enhanced Raman spectroscopy applications, in which the field enhancement is used to amplify the usually weak Raman scattering signal. The hot spots are mostly generated between two or more plasmonic nanostructures separated by nanometric gaps. Several strategies are used to design and realize the hot spots, both in solution, using the noble metal nanoparticles, and on surfaces, using nanolithography and evaporation. In this paper, we demonstrated the fabrication of a nanomechanical plasmonic device for Raman spectroscopy, in which the hot spots are switched on when biased at the resonant frequency and switched off when the actuation signal is removed.

  18. Evolution of Hot Gas in Elliptical Galaxies

    NASA Technical Reports Server (NTRS)

    Mathews, William G.

    2004-01-01

    This theory grant was awarded to study the curious nature, origin and evolution of hot gas in elliptical galaxies and their surrounding groups. Understanding the properties of this X-ray emitting gas has profound implications over the broad landscape of modern astrophysics: cosmology, galaxy formation, star formation, cosmic metal enrichment, galactic structure and dynamics, and the physics of hot gases containing dust and magnetic fields. One of our principal specific objectives was to interpret the marvelous new observations from the XMM and Chandru satellite X-ray telescopes.

  19. The Earth's Hot Spots.

    ERIC Educational Resources Information Center

    Vink, Gregory E.; And Others

    1985-01-01

    Hot spots are isolated areas of geologic activity where volcanic eruptions, earthquakes, and upwelling currents occur far from plate boundaries. These mantle plumes are relatively stable and crustal plates drift over them. The nature and location of hot spots (with particular attention to the Hawaiian Islands and Iceland) are discussed. (DH)

  20. Hot Spot at Yellowstone

    ERIC Educational Resources Information Center

    Dress, Abby

    2005-01-01

    Within this huge national park (over two million acres spread across Wyoming, Montana, and Idaho) are steaming geysers, hot springs, bubbling mudpots, and fumaroles, or steam vents. Drives on the main roads of Yellowstone take tourists through the major hot attractions, which also include Norris Geyser Basin, Upper and Lower Geyser Basin, West…

  1. 6. HOT AIR PORTION OF DAMPERS. Hot Springs National ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. HOT AIR PORTION OF DAMPERS. - Hot Springs National Park, Bathhouse Row, Lamar Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  2. Hot-Carrier Seebeck Effect: Diffusion and Remote Detection of Hot Carriers in Graphene.

    PubMed

    Sierra, Juan F; Neumann, Ingmar; Costache, Marius V; Valenzuela, Sergio O

    2015-06-10

    We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage V(NL) across the remaining (detector) leads. Due to the nonlocal character of the measurement, V(NL) is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and V(NL), V(NL) ∼ P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying V(NL) as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport. PMID:25950746

  3. Hot Accretion Disks Revisited

    NASA Astrophysics Data System (ADS)

    Bjoernsson, Gunnlaugur; Abramowicz, Marek A.; Chen, Xingming; Lasota, Jean-Pierre

    1996-08-01

    All previous studies of hot (Tp 1010-1012 K), optically thin accretion disks have neglected either the presence of e+ e- pairs or advective cooling. Thus all hot disk models constructed previously have not been self-consistent. In this paper we calculate local disk models including pair physics, relevant radiative processes in the hot plasma, and the effect of advective cooling. We use a modification of the Björnsson & Svensson mapping method. We find that the role of e+ e- pairs in the structure of hot, optically thin accretion disks is far less significant than was previously thought. The improved description of the radiation-matter interactions provided in the present paper modify the previously obtained values of the critical parameters characterizing advectively dominated flows.

  4. Saturn's Hot Plasma Explosions

    NASA Video Gallery

    This animation based on data obtained by NASA's Cassini Spacecraft shows how the "explosions" of hot plasma on the night side (orange and white) periodically inflate Saturn's magnetic field (white ...

  5. Hot Oiling Spreadsheet

    1993-10-22

    One of the most common oil-field treatments is hot oiling to remove paraffin from wells. Even though the practice is common, the thermal effectiveness of the process is not commonly understood. In order for producers to easily understand the thermodynamics of hot oiling, a simple tool is needed for estimating downhole temperatures. Such a tool has been developed that can be distributed as a compiled spreadsheet.

  6. Geothermal hot water system

    SciTech Connect

    Dittell, E.W.

    1983-05-10

    Geothermal hot water system including a hot water tank and a warm water tank which are heated independently of each other by a close loop freon system. The closed loop freon system includes a main condenser which heats water for the warm water tank and a super-heated condenser which heats water for the hot water tank, and where the freon passes through a water evaporator which is heated by water such as from a well or other suitable source. The water evaporator in the closed loop freon system passes the water through but no environmental change to the water. An electrical circuit including aquastats in the warm water tank connected therethrough controls operation of the closed loop freon system including respective pumps on the super-heated condenser and main condenser for pumping water. Pumps pump water through the main condenser for the warm tank and through the super-heated condenser for the hot tank. The system provides for energy conservation in that the head pressure of the compressor is kept in the lower operating ranges as determined by the discharge flow of the main condenser which varies by the head pressure and temperature flow control which varies by temperature. The geothermal hot water system uses a least amount of energy in heating the water in the hot tank as well as the warm tank.

  7. Hot Carrier Extraction with Plasmonic Broadband Absorbers.

    PubMed

    Ng, Charlene; Cadusch, Jasper J; Dligatch, Svetlana; Roberts, Ann; Davis, Timothy J; Mulvaney, Paul; Gómez, Daniel E

    2016-04-26

    Hot charge carrier extraction from metallic nanostructures is a very promising approach for applications in photocatalysis, photovoltaics, and photodetection. One limitation is that many metallic nanostructures support a single plasmon resonance thus restricting the light-to-charge-carrier activity to a spectral band. Here we demonstrate that a monolayer of plasmonic nanoparticles can be assembled on a multistack layered configuration to achieve broadband, near-unit light absorption, which is spatially localized on the nanoparticle layer. We show that this enhanced light absorbance leads to ∼40-fold increases in the photon-to-electron conversion efficiency by the plasmonic nanostructures. We developed a model that successfully captures the essential physics of the plasmonic hot electron charge generation and separation in these structures. This model also allowed us to establish that efficient hot carrier extraction is limited to spectral regions where (i) the photons have energies higher than the Schottky junctions and (ii) the absorption of light is localized on the metal nanoparticles.

  8. Theory of hot electron photoemission from graphene

    NASA Astrophysics Data System (ADS)

    Ang, Lay Kee; Liang, Shijun

    Motivated by the development of Schottky-type photodetectors, some theories have been proposed to describe how the hot carriers generated by the incident photon are transported over the Schottky barrier through the internal photoelectric effect. One of them is Fowler's law proposed as early as 1931, which studied the temperature dependence of photoelectric curves of clean metals. This law is very successful in accounting for mechanism of detecting photons of energy lower than the band gap of semiconductor based on conventional metal/semiconductor Schottky diode. With the goal of achieving better performance, graphene/silicon contact-based- graphene/WSe2 heterostructure-based photodetectors have been fabricated to demonstrate superior photodetection efficiency. However, the theory of how hot electrons is photo-excited from graphene into semiconductor remains unknown. In the current work, we first examine the photoemission process from suspended graphene and it is found that traditional Einstein photoelectric effect may break down for suspended graphene due to the unique linear band structure. Furthermore, we find that the same conclusion applies for 3D graphene analog (e.g. 3D topological Dirac semi-metal). These findings are very useful to further improve the performance of graphene-based photodetector, hot-carrier solar cell and other kinds of sensor.

  9. Embedding plasmonic nanostructure diodes enhances hot electron emission.

    PubMed

    Knight, Mark W; Wang, Yumin; Urban, Alexander S; Sobhani, Ali; Zheng, Bob Y; Nordlander, Peter; Halas, Naomi J

    2013-04-10

    When plasmonic nanostructures serve as the metallic counterpart of a metal-semiconductor Schottky interface, hot electrons due to plasmon decay are emitted across the Schottky barrier, generating measurable photocurrents in the semiconductor. When the plasmonic nanostructure is atop the semiconductor, only a small percentage of hot electrons are excited with a wavevector permitting transport across the Schottky barrier. Here we show that embedding plasmonic structures into the semiconductor substantially increases hot electron emission. Responsivities increase by 25× over planar diodes for embedding depths as small as 5 nm. The vertical Schottky barriers created by this geometry make the plasmon-induced hot electron process the dominant contributor to photocurrent in plasmonic nanostructure-diode-based devices. PMID:23452192

  10. HOT CELL BUILDING, TRA632, INTERIOR. DETAIL OF HOT CELL NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HOT CELL BUILDING, TRA-632, INTERIOR. DETAIL OF HOT CELL NO. 2 SHOWS MANIPULATION INSTRUMENTS AND SHIELDED OPERATING WINDOWS. PENETRATIONS FOR OPERATING INSTRUMENTS GO THROUGH SHIELDING ABOVE WINDOWS. CONDUIT FOR UTILITIES AND CONTROLS IS BEHIND METAL CABINET BELOW WINDOWS NEAR FLOOR. CAMERA FACES WEST. WARNING SIGN LIMITS FISSILE MATERIAL TO SPECIFIED NUMBER OF GRAMS OF URANIUM AND PLUTONIUM. INL NEGATIVE NO. HD46-28-2. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  11. Hot-carrier-induced linear drain current and threshold voltage degradation for thin layer silicon-on-insulator field P-channel lateral double-diffused metal-oxide-semiconductor

    SciTech Connect

    Zhou, Xin; Qiao, Ming; He, Yitao; Li, Zhaoji; Zhang, Bo

    2015-11-16

    Hot-carrier-induced linear drain current (I{sub dlin}) and threshold voltage (V{sub th}) degradations for the thin layer SOI field p-channel lateral double-diffused MOS (pLDMOS) are investigated. Two competition degradation mechanisms are revealed and the hot-carrier conductance modulation model is proposed. In the channel, hot-hole injection induced positive oxide trapped charge and interface trap gives rise to the V{sub th} increasing and the channel conductance (G{sub ch}) decreasing, then reduces I{sub dlin}. In the p-drift region, hot-electron injection induced negative oxide trapped charge enhances the conductance of drift doping resistance (G{sub d}), and then increases I{sub dlin}. Consequently, the eventual I{sub dlin} degradation is controlled by the competition of the two mechanisms due to conductance modulation in the both regions. Based on the model, it is explained that the measured I{sub dlin} anomalously increases while the V{sub th} is increasing with power law. The thin layer field pLDMOS exhibits more severe V{sub th} instability compared with thick SOI layer structure; as a result, it should be seriously evaluated in actual application in switching circuit.

  12. Hot-carrier-induced linear drain current and threshold voltage degradation for thin layer silicon-on-insulator field P-channel lateral double-diffused metal-oxide-semiconductor

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Qiao, Ming; He, Yitao; Li, Zhaoji; Zhang, Bo

    2015-11-01

    Hot-carrier-induced linear drain current (Idlin) and threshold voltage (Vth) degradations for the thin layer SOI field p-channel lateral double-diffused MOS (pLDMOS) are investigated. Two competition degradation mechanisms are revealed and the hot-carrier conductance modulation model is proposed. In the channel, hot-hole injection induced positive oxide trapped charge and interface trap gives rise to the Vth increasing and the channel conductance (Gch) decreasing, then reduces Idlin. In the p-drift region, hot-electron injection induced negative oxide trapped charge enhances the conductance of drift doping resistance (Gd), and then increases Idlin. Consequently, the eventual Idlin degradation is controlled by the competition of the two mechanisms due to conductance modulation in the both regions. Based on the model, it is explained that the measured Idlin anomalously increases while the Vth is increasing with power law. The thin layer field pLDMOS exhibits more severe Vth instability compared with thick SOI layer structure; as a result, it should be seriously evaluated in actual application in switching circuit.

  13. Development of iron-aluminide hot-gas filters

    SciTech Connect

    Tortorelli, P.F.; Wright, I.G.; Judkins, R.R.

    1996-06-01

    Removal of particles from hot synthesis gas produced by coal gasification is vital to the success of these systems. In Integrated [Coal] Gasification Combined Cycle systems, the synthesis gas is the fuel for gas turbines. To avoid damage to turbine components, it is necessary that particles be removed from the fuel gas prior to combustion and introduction into the turbine. Reliability and durability of the hot-gas filtering devices used to remove the particles is, of course, of special importance. Hot-gas filter materials include both ceramics and metals. Numerous considerations must be made in selecting materials for these filters. Constituents in the hot gases may potentially degrade the properties and performance of the filters to the point that they are ineffective in removing the particles. Very significant efforts have been made by DOE and others to develop effective hot-particle filters and, although improvements have been made, alternative materials and structures are still needed.

  14. The effect of hot electrons and surface plasmons on heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Kim, Sun Mi; Lee, Si Woo; Moon, Song Yi; Park, Jeong Young

    2016-06-01

    Hot electrons and surface-plasmon-driven chemistry are amongst the most actively studied research subjects because they are deeply associated with energy dissipation and the conversion processes at the surface and interfaces, which are still open questions and key issues in the surface science community. In this topical review, we give an overview of the concept of hot electrons or surface-plasmon-mediated hot electrons generated under various structural schemes (i.e. metals, metal–semiconductor, and metal–insulator–metal) and their role affecting catalytic activity in chemical reactions. We highlight recent studies on the relation between hot electrons and catalytic activity on metallic surfaces. We discuss possible mechanisms for how hot electrons participate in chemical reactions. We also introduce controlled chemistry to describe specific pathways for selectivity control in catalysis on metal nanoparticles.

  15. Dispersants displace hot oiling

    SciTech Connect

    Wash, R.

    1984-02-01

    Laboratory experiments and field testing of dispersants in producing wells have resulted in development of 2 inexpensive paraffin dispersant packages with a broad application range, potential for significant savings over hot oiling, and that can be applied effectively by both continuous and batch treating techniques. The 2 dispersants are soluble in the carrier solvent (one soluble in oil, one in water); are able to readily disperse the wax during a hot flask test conducted in a laboratory; and leave the producing interval water wet. Field data on the 2 dispersants are tabulated, demonstrating their efficacy.

  16. Hot Oil Removes Wax

    NASA Technical Reports Server (NTRS)

    Herzstock, James J.

    1991-01-01

    Mineral oil heated to temperature of 250 degrees F (121 degrees C) found effective in removing wax from workpieces after fabrication. Depending upon size and shape of part to be cleaned of wax, part immersed in tank of hot oil, and/or interior of part flushed with hot oil. Pump, fittings, and ancillary tooling built easily for this purpose. After cleaning, innocuous oil residue washed off part by alkaline aqueous degreasing process. Serves as relatively safe alternative to carcinogenic and environmentally hazardous solvent perchloroethylene.

  17. APPARATUS FOR HIGH PURITY METAL RECOVERY

    DOEpatents

    Magel, T.T.

    1959-02-10

    An apparatus is described for preparing high purity metal such as uranium, plutonium and the like from an impure mass of the same metal. The apparatus is arranged so that the impure metal is heated and swept by a stream of hydrogen gas bearing a halogen such as iodine. The volatiie metal halide formed is carried on to a hot filament where the metal halide is decomposed and the molten high purity metal is collected in a rceeiver below

  18. Hot-hole photodetectors

    NASA Astrophysics Data System (ADS)

    2014-05-01

    By injecting high-energy charge carriers (dubbed 'hot holes') into a semiconductor, scientists have succeeded in realizing photodetectors capable of detecting ultralong wavelengths. Unil Perera from Georgia State University in the USA explains how the devices work and how they can be improved.

  19. Hot off the Press

    ERIC Educational Resources Information Center

    Brisco, Nicole D.

    2007-01-01

    In the past, the newspaper was one of the world's most used sources of information. Recently, however, its use has declined due to the popularity of cable television and the Internet. Yet the idea of reading the morning paper with a hot cup of coffee holds many warm memories for children who watched their parents in this daily ritual. In this…

  20. Zen Hot Dog Molecules

    ERIC Educational Resources Information Center

    Ryan, Dennis

    2009-01-01

    Substituted cycloalkanes with one branch illustrating each topic in an instructional unit can serve as summaries or reviews in courses of organic chemistry. The hungry Zen master told the hot dog vendor to make him one with everything. You can do the same for your students.

  1. Hot piston ring tests

    NASA Astrophysics Data System (ADS)

    Allen, David J.; Tomazic, William A.

    1987-12-01

    As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

  2. What's Hot? What's Not?

    ERIC Educational Resources Information Center

    Buczynski, Sandy

    2006-01-01

    When Goldilocks finds three bowls of porridge at different temperatures in the three bears' house, she accurately assesses the situation and comes up with one of the most recognizable lines in children's literature," This porridge is too hot; this porridge is too cold; aahh, this porridge is just right!" Goldilocks' famous line is a perfect…

  3. Zen Hot Dog Molecules

    NASA Astrophysics Data System (ADS)

    Ryan, Dennis

    2009-04-01

    Substituted cycloalkanes with one branch illustrating each topic in an instructional unit can serve as summaries or reviews in courses of organic chemistry. The hungry Zen master told the hot dog vendor to make him one with everything. You can do the same for your students.

  4. Hot piston ring tests

    NASA Technical Reports Server (NTRS)

    Allen, David J.; Tomazic, William A.

    1987-01-01

    As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

  5. Horseshoe pitchers' hot hands.

    PubMed

    Smith, Gary

    2003-09-01

    Gilovich, Vallone, and Tversky's (1985) analysis of basketball data indicates that a player's chances of making a shot are not affected by the results of earlier shots. However, their basketball data do not control for several confounding influences. An analysis of horseshoe pitching, which does not have these defects, indicates that players do have modest hot and cold spells.

  6. The Hot Gaseous Halos of Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Bregman, J.

    2016-06-01

    In the Milky Way, absorption and emission line measurements of O VII and O VIII show that the halo environment is dominated by a nearly spherical halo of temperature 2 × 10^6 K, metallicity of 0.3-0.5 solar, and with a density decreasing as r^{-3/2}. The mass of the hot gas, estimated through extrapolation to the virial radius, is comparable to the stellar mass, but does not account for the missing mass. The Milky Way hot halo appears to be rotating at about 180 km/s, which is consistent with model expectations, depending on the time of infall. Around massive spiral galaxies, hot halos are seen in emission out to about 70 kpc in the best cases. These show similar gas density laws and metallicities in the range 0.1-0.5 solar. The gas mass is comparable to the stellar mass, but does not account for the missing baryons within the virial radius. If the density law can be extrapolated to about three virial radii, the missing baryons would be accounted for.

  7. Hot Tub Rash (Pseudomonas Folliculitis)

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Hot Tub Rash ( Pseudomonas Folliculitis) Information for adults A ... the skin and small pus-filled lesions. Overview Hot tub rash ( Pseudomonas folliculitis) is an infection of ...

  8. Enabling Technologies for Ceramic Hot Section Components

    SciTech Connect

    Venkat Vedula; Tania Bhatia

    2009-04-30

    Silicon-based ceramics are attractive materials for use in gas turbine engine hot sections due to their high temperature mechanical and physical properties as well as lower density than metals. The advantages of utilizing ceramic hot section components include weight reduction, and improved efficiency as well as enhanced power output and lower emissions as a result of reducing or eliminating cooling. Potential gas turbine ceramic components for industrial, commercial and/or military high temperature turbine applications include combustor liners, vanes, rotors, and shrouds. These components require materials that can withstand high temperatures and pressures for long duration under steam-rich environments. For Navy applications, ceramic hot section components have the potential to increase the operation range. The amount of weight reduced by utilizing a lighter gas turbine can be used to increase fuel storage capacity while a more efficient gas turbine consumes less fuel. Both improvements enable a longer operation range for Navy ships and aircraft. Ceramic hot section components will also be beneficial to the Navy's Growth Joint Strike Fighter (JSF) and VAATE (Versatile Affordable Advanced Turbine Engines) initiatives in terms of reduced weight, cooling air savings, and capability/cost index (CCI). For DOE applications, ceramic hot section components provide an avenue to achieve low emissions while improving efficiency. Combustors made of ceramic material can withstand higher wall temperatures and require less cooling air. Ability of the ceramics to withstand high temperatures enables novel combustor designs that have reduced NO{sub x}, smoke and CO levels. In the turbine section, ceramic vanes and blades do not require sophisticated cooling schemes currently used for metal components. The saved cooling air could be used to further improve efficiency and power output. The objectives of this contract were to develop technologies critical for ceramic hot section

  9. Metal Preferences and Metallation*

    PubMed Central

    Foster, Andrew W.; Osman, Deenah; Robinson, Nigel J.

    2014-01-01

    The metal binding preferences of most metalloproteins do not match their metal requirements. Thus, metallation of an estimated 30% of metalloenzymes is aided by metal delivery systems, with ∼25% acquiring preassembled metal cofactors. The remaining ∼70% are presumed to compete for metals from buffered metal pools. Metallation is further aided by maintaining the relative concentrations of these pools as an inverse function of the stabilities of the respective metal complexes. For example, magnesium enzymes always prefer to bind zinc, and these metals dominate the metalloenzymes without metal delivery systems. Therefore, the buffered concentration of zinc is held at least a million-fold below magnesium inside most cells. PMID:25160626

  10. Hot Billet Surface Qualifier

    SciTech Connect

    Tzyy-Shuh Chang

    2007-04-30

    OG Technologies, Inc. (OGT), developed a prototype of a Hot Billet Surface Qualifier (“Qualifier”) based on OGT’s patented HotEye™ technology and other proprietary imaging and computing technologies. The Qualifier demonstrated its ability of imaging the cast billets in line with high definition pictures, pictures capable of supporting the detection of surface anomalies on the billets. The detection will add the ability to simplify the subsequent process and to correct the surface quality issues in a much more timely and efficient manner. This is challenging due to the continuous casting environment, in which corrosive water, temperature, vibration, humidity, EMI and other unbearable factors exist. Each installation has the potential of 249,000 MMBTU in energy savings per year. This represents a cost reduction, reduced emissions, reduced water usage and reduced mill scale.

  11. Hot Spring Metagenomics

    PubMed Central

    López-López, Olalla; Cerdán, María Esperanza; González-Siso, María Isabel

    2013-01-01

    Hot springs have been investigated since the XIX century, but isolation and examination of their thermophilic microbial inhabitants did not start until the 1950s. Many thermophilic microorganisms and their viruses have since been discovered, although the real complexity of thermal communities was envisaged when research based on PCR amplification of the 16S rRNA genes arose. Thereafter, the possibility of cloning and sequencing the total environmental DNA, defined as metagenome, and the study of the genes rescued in the metagenomic libraries and assemblies made it possible to gain a more comprehensive understanding of microbial communities—their diversity, structure, the interactions existing between their components, and the factors shaping the nature of these communities. In the last decade, hot springs have been a source of thermophilic enzymes of industrial interest, encouraging further study of the poorly understood diversity of microbial life in these habitats. PMID:25369743

  12. Hot spring metagenomics.

    PubMed

    López-López, Olalla; Cerdán, María Esperanza; González-Siso, María Isabel

    2013-01-01

    Hot springs have been investigated since the XIX century, but isolation and examination of their thermophilic microbial inhabitants did not start until the 1950s. Many thermophilic microorganisms and their viruses have since been discovered, although the real complexity of thermal communities was envisaged when research based on PCR amplification of the 16S rRNA genes arose. Thereafter, the possibility of cloning and sequencing the total environmental DNA, defined as metagenome, and the study of the genes rescued in the metagenomic libraries and assemblies made it possible to gain a more comprehensive understanding of microbial communities-their diversity, structure, the interactions existing between their components, and the factors shaping the nature of these communities. In the last decade, hot springs have been a source of thermophilic enzymes of industrial interest, encouraging further study of the poorly understood diversity of microbial life in these habitats. PMID:25369743

  13. Hot chocolate effect

    SciTech Connect

    Crawford, F.S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  14. The hot chocolate effect

    SciTech Connect

    Crawford, Frank S.

    1982-05-01

    The "hot chocolate effect" was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the ten percent accuracy of the experiments.

  15. The ''hot'' patella

    SciTech Connect

    Kipper, M.S.; Alazraki, N.P.; Feiglin, D.H.

    1982-01-01

    Increased patellar uptake on bone scans is seen quite commonly but the possible or probable etiologies of this finding have not been previously well described. A review of 100 consecutive bone scans showed that the incidence of bilateral ''hot'' patellae is 15%. Identified etiologies include osteoarthritic degenerative disease (35%), fracture, possible metastatic disease, bursitis, Paget's disease, and osteomyelitis. The value of careful history, physical examination, and radiographs is stressed.

  16. Jupiter's Hot, Mushy Moon

    NASA Technical Reports Server (NTRS)

    Taylor, G. Jeffrey

    2003-01-01

    Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

  17. Solar Hot Water Heater

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  18. STRIPPING METAL COATINGS

    DOEpatents

    Siefen, H.T.; Campbell, J.M.

    1959-02-01

    A method is described for removing aluminumuranium-silicon alloy bonded to metallic U comprising subjecting the Al-U -Si alloy to treatment with hot concentrated HNO/sun 3/ to partially dissolve and embrittle the alloy and shot- blasting the embrittled alloy to loosen it from the U.

  19. STIS CCD Hot Pixel Annealing

    NASA Astrophysics Data System (ADS)

    Hernandez, Svea

    2013-10-01

    This purpose of this activity is to repair radiation induced hot pixel damage to theSTIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation damaged pixels. Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near-83 C to the ambient instrument temperature { +5 C} for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.

  20. PREFACE: Hot Quarks 2004

    NASA Astrophysics Data System (ADS)

    Antinori, Federico; Bass, Steffen A.; Bellwied, Rene; Ullrich, Thomas; Velkovska, Julia; Wiedemann, Urs

    2005-04-01

    Why another conference devoted to ultra-relativistic heavy-ion physics? As we looked around the landscape of the existing international conferences and workshops, we realized that there was not a single one tailored to the people who are most directly involved with the actual research work: students, post-docs, and junior faculty/research scientists. Of course there are schools, but that was not what we had in mind. We wanted a meeting where young researchers could come together to discuss in depth the physics that they are working on without any hindrance. The major conferences have very limited time for discussions which is often shared amongst the most established. This leaves little room for young people to ask their questions and to get the detailed feedback which they deserve and which satisfies their curiosity. A discussion-driven workshop, centering on those without whom there will be no future—that seemed like what was needed. And thus the Hot Quarks workshop was born. The aim of Hot Quarks was to enhance the direct exchange of scientific information among the younger members of the community, from both experiment and theory. Participation was by invitation only in order to emphasize the contributions from junior researchers. This approach makes the workshop unique among the many forums in the field. For young scientists it represented an opportunity for exposure that they would not have had in one of the major conferences. The hope is that this meeting has helped to stimulate the next generation of scientists in our field and, at the same time, strengthened their sense of community. It all came together from 18 24 July 2004, when the 77 participants met at The Inn at Snakedance in the Taos Ski Valley, New Mexico, USA, for the first Hot Quarks workshop. Photograph Participants gather in the sunshine at the foot of the Taos Ski Valley chairlift. By all accounts, Hot Quarks 2004 was a great success. Every participant had the opportunity to present her or

  1. Sewage sludge dewatering using flowing liquid metals

    DOEpatents

    Carlson, Larry W.

    1986-01-01

    A method and apparatus for reducing the moisture content of a moist sewage sludge having a moisture content of about 50% to 80% and formed of small cellular micro-organism bodies having internally confined water is provided. A hot liquid metal is circulated in a circulation loop and the moist sewage sludge is injected in the circulation loop under conditions of temperature and pressure such that the confined water vaporizes and ruptures the cellular bodies. The vapor produced, the dried sludge, and the liquid metal are then separated. Preferably, the moist sewage sludge is injected into the hot liquid metal adjacent the upstream side of a venturi which serves to thoroughly mix the hot liquid metal and the moist sewage sludge. The venturi and the drying zone after the venturi are preferably vertically oriented. The dried sewage sludge recovered is available as a fuel and is preferably used for heating the hot liquid metal.

  2. Filter for cleaning hot gases

    SciTech Connect

    Gresch, H.; Holter, H.; Hubner, K.; Igelbuscher, H.; Weber, E.

    1981-10-20

    In an apparatus for cleaning hot gases a filter housing has an inlet for unfiltered gas and an outlet for filtered gas. A plurality of filtered inserts are placed within the housing in a manner capable of filtering undesirable components from the gas feed stream. Each filter insert is made of a fibrous filter material. Silicic-acid glass fibers have a silicic acid content of at least 90%. Coated upon the fibers and absorbed into their pores is a metal oxide of aluminum, titanium, zirconium, cromium, nickle or cobalt. A honeycombed cage filled with high temperature resistant perlite is located within the housing between the gas inlet and the fiber inserts. The cage has an inlet and outlet external to the housing for replacing the perlite. A combustion chamber mounted in the housing has a discharge nozzle located so that the nozzle is directed at the filter inserts. Combusting materials in the chamber causes an explosive backflow of gases through the filter inserts.

  3. Correcting lithography hot spots during physical-design implementation

    NASA Astrophysics Data System (ADS)

    Luk-Pat, Gerard T.; Miloslavsky, Alexander; Ikeuchi, Atsuhiko; Suzuki, Hiroaki; Kyoh, Suigen; Izuha, Kyoko; Tseng, Frank; Wen, Linni

    2006-10-01

    As the technology node shrinks, printed-wafer shapes show progressively less similarity to the design-layout shapes, even with optical proximity correction (OPC). Design tools have a restricted ability to address this shape infidelity. Their understanding of lithography effects is limited, taking the form of design rules that try to prevent "Hot Spots" - locations that demonstrate wafer-printing problems. These design rules are becoming increasingly complex and therefore less useful in addressing the lithography challenges. Therefore, design tools that have a better understanding of lithography are becoming a necessity for technology nodes of 65 nm and below. The general goal of this work is to correct lithography Hot Spots during physical-design implementation. The specific goal is to automatically fix a majority of the Hot Spots in the Metal 2 layers and above, with a run time on the order of a few hours per layer. Three steps were taken to achieve this goal. First, Hot Spot detection was made faster by using rule-based detection. Second, Hot Spot correction was automated by using rule-based correction. Third, convergence of corrections was avoided by performing correction locally, which means that correcting one Hot Spot was very unlikely to create new Hot Spots.

  4. Not so hot "hot spots" in the oceanic mantle.

    PubMed

    Bonath, E

    1990-10-01

    Excess volcanism and crustal swelling associated with hot spots are generally attributed to thermal plumes upwelling from the mantle. This concept has been tested in the portion of the Mid-Atlantic Ridge between 34 degrees and 45 degrees (Azores hot spot). Peridotite and basalt data indicate that the upper mantle in the hot spot has undergone a high degree of melting relative to the mantle elsewhere in the North Atlantic. However, application of various geothermometers suggests that the temperature of equilibration of peridotites in the mantle was lower, or at least not higher, in the hot spot than elsewhere. The presence of H(2)O-rich metasomatized mantle domains, inferred from peridotite and basalt data, would lower the melting temperature of the hot spot mantle and thereby reconcile its high degree ofmelting with the lack of a mantle temperature anomaly. Thus, some so-called hot spots might be melting anomalies unrelated to abnormally high mantle temperature or thermal plumes.

  5. Hot oiling spreadsheet

    SciTech Connect

    Mansure, A.J.

    1996-09-01

    One of the most common oil-field treatments is hot oiling to remove paraffin from wells. Even though the practice is common, the thermal effectiveness of the process is not commonly understood. In order for producers to easily understand the thermodynamics of hot oiling, a simple tool is needed for estimating downhole temperatures. Such a tool has been developed that was distributed as a compiled, public-domain-software spreadsheet. That spreadsheet has evolved into an interactive from on the World Wide Web and has been adapted into a Windows{trademark} program by Petrolite, St. Louis MO. The development of such a tools was facilitated by expressing downhole temperatures in terms of analytic formulas. Considerable algebraic work is required to develop such formulas. Also, the data describing hot oiling is customarily a mixture of practical units that must be converted to a consistent set of units. To facilitate the algebraic manipulations and to assure unit conversions are correct, during development parallel calculations were made using the spreadsheet and a symbolic mathematics program. Derivation of the formulas considered falling film flow in the annulus and started from the transient differential equations so that the effects of the heat capacity of the tubing and casing could be included. While this approach to developing a software product does not have the power and sophistication of a finite element or difference code, it produces a user friendly product that implements the equations solved with a minimum potential for bugs. This allows emphasis in development of the product to be placed on the physics.

  6. Method and apparatus for determining weldability of thin sheet metal

    DOEpatents

    Goodwin, Gene M.; Hudson, Joseph D.

    1988-01-01

    A fixture is provided for testing thin sheet metal specimens to evaluate hot-cracking sensitivity for determining metal weldability on a heat-to-heat basis or through varying welding parameters. A test specimen is stressed in a first direction with a load selectively adjustable over a wide range and then a weldment is passed along over the specimen in a direction transverse to the direction of strain to evaluate the hot-cracking characteristics of the sheet metal which are indicative of the weldability of the metal. The fixture provides evaluations of hot-cracking sensitivity for determining metal weldability in a highly reproducible manner with minimum human error.

  7. Hot cell examination table

    DOEpatents

    Gaal, Peter S.; Ebejer, Lino P.; Kareis, James H.; Schlegel, Gary L.

    1991-01-01

    A table for use in a hot cell or similar controlled environment for use in examining specimens. The table has a movable table top that can be moved relative to a table frame. A shaft is fixedly mounted to the frame for axial rotation. A shaft traveler having a plurality of tilted rollers biased against the shaft is connected to the table top such that rotation of the shaft causes the shaft traveler to roll along the shaft. An electromagnetic drive is connected to the shaft and the frame for controllably rotating the shaft.

  8. Hot air drum evaporator

    DOEpatents

    Black, Roger L.

    1981-01-01

    An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

  9. MSFC hot air collectors

    NASA Technical Reports Server (NTRS)

    Anthony, K.

    1978-01-01

    A description of the hot air collector is given that includes a history of development, a history of the materials development, and a program summary. The major portion of the solar energy system cost is the collector. Since the collector is the heart of the system and the most costly subsystem, reducing the cost of producing collectors in large quantities is a major goal. This solar collector is designed to heat air and/or water cheaply and efficiently through the use of solar energy.

  10. Hot cell examination table

    SciTech Connect

    Gaal, P.S.; Ebjer, L.P.; Kareis, J.H.; Schlegel, G.L.

    1990-01-01

    This invention is comprised of a table for use in a hot cell or similar controlled environment for use in examining specimens. The table has a movable table top that can be moved relative to a table frame. A shaft is fixedly mounted to the frame for axial rotation. A shaft traveler having a plurality of tilted rollers biased against the shaft is connected to the table top such that rotation of the shaft causes the shaft traveler to roll along the shaft. An electromagnetic drive is connected to the shaft and the frame for controllably rotating the shaft.

  11. Dry soldering with hot filament produced atomic hydrogen

    DOEpatents

    Panitz, J.K.G.; Jellison, J.L.; Staley, D.J.

    1995-04-25

    A system is disclosed for chemically transforming metal surface oxides to metal that is especially, but not exclusively, suitable for preparing metal surfaces for dry soldering and solder reflow processes. The system employs one or more hot, refractory metal filaments, grids or surfaces to thermally dissociate molecular species in a low pressure of working gas such as a hydrogen-containing gas to produce reactive species in a reactive plasma that can chemically reduce metal oxides and form volatile compounds that are removed in the working gas flow. Dry soldering and solder reflow processes are especially applicable to the manufacture of printed circuit boards, semiconductor chip lead attachment and packaging multichip modules. The system can be retrofitted onto existing metal treatment ovens, furnaces, welding systems and wave soldering system designs. 1 fig.

  12. Dry soldering with hot filament produced atomic hydrogen

    DOEpatents

    Panitz, Janda K. G.; Jellison, James L.; Staley, David J.

    1995-01-01

    A system for chemically transforming metal surface oxides to metal that is especially, but not exclusively, suitable for preparing metal surfaces for dry soldering and solder reflow processes. The system employs one or more hot, refractory metal filaments, grids or surfaces to thermally dissociate molecular species in a low pressure of working gas such as a hydrogen-containing gas to produce reactive species in a reactive plasma that can chemically reduce metal oxides and form volatile compounds that are removed in the working gas flow. Dry soldering and solder reflow processes are especially applicable to the manufacture of printed circuit boards, semiconductor chip lead attachment and packaging multichip modules. The system can be retrofitted onto existing metal treatment ovens, furnaces, welding systems and wave soldering system designs.

  13. Radiations from hot nuclei

    NASA Technical Reports Server (NTRS)

    Malik, F. Bary

    1993-01-01

    The investigation indicates that nuclei with excitation energy of a few hundred MeV to BeV are more likely to radiate hot nuclear clusters than neutrons. These daughter clusters could, furthermore, de-excite emitting other hot nuclei, and the chain continues until these nuclei cool off sufficiently to evaporate primarily neutrons. A few GeV excited nuclei could radiate elementary particles preferentially over neutrons. Impact of space radiation with materials (for example, spacecraft) produces highly excited nuclei which cool down emitting electromagnetic and particle radiations. At a few MeV excitation energy, neutron emission becomes more dominant than gamma-ray emission and one often attributes the cooling to take place by successive neutron decay. However, a recent experiment studying the cooling process of 396 MeV excited Hg-190 casts some doubt on this thinking, and the purpose of this investigation is to explore the possibility of other types of nuclear emission which might out-compete with neutron evaporation.

  14. Hot, Dry and Cloudy

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Hot, Dry and Cloudy

    This artist's concept shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two 'hot Jupiter' worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

    The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the 'fingerprints' of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

    Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

    This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged

  15. Hot Subdwarf Star Membership in Visual Binaries

    NASA Astrophysics Data System (ADS)

    Wade, R. A.; Stark, M. A.

    2001-05-01

    We have inspected more than 1300 regions (6 x 6 arcmin) of the first Digitized Sky Survey, each centered on the position of a hot subdwarf star (sdB or sdO star). Several per cent of these subdwarfs are found, on a statistical basis, to be reasonably convincing candidate members of wide binaries (common--proper--motion pairs of stars), and another several per cent are identified as possible c.p.m. candidates (wider separations, more crowded fields, etc.). In very crowded fields, no identification of pairs was attempted. Confirmation of these candidate binary systems awaits radial velocity and proper motion studies. In most cases, the red magnitude of the hot subdwarf and its proposed fellow traveler are similar, although this is partly a selection effect. We will present what is currently known about these pairs of stars: photographic magnitude differences and colors, distribution of angular separation vs magnitude, 2MASS colors, etc. We will also present validating studies of control fields, to assess whether the fraction of hot subdwarfs that are visual binary candidates is higher than field stars of similar magnitude. This sample of stars cannot be regarded as complete in any rigorous way and is certainly biased by the selection process. We can nevertheless hope to exploit the (to--be--purified) sample to learn much about the luminosities, ages, and original metallicities of the hot subdwarf stars, and possibly their companions can be used as a kinematically unbiased sample of old disk stars. Supported in part by NASA. This work made use of the Digitized Sky Surveys produced at the Space Telescope Science Institute, the 2MASS Second Incremental Data Release, and the U.S. Naval Observatory USNO-A2 catalogue.

  16. How Deep and Hot was Earth's Magma Ocean? Combined Experimental Datasets for the Metal-silicate Partitioning of 11 Siderophile Elements - Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd

    NASA Technical Reports Server (NTRS)

    Righter, Kevin

    2008-01-01

    Since approximately 1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients (D) for siderophile (iron-loving) elements are much different than those measured at low PT conditions. The high PT data have been used to argue for a magma ocean during growth of the early Earth. Initial conclusions were based on experiments and calculations for a small number of elements such as Ni and Co. However, for many elements only a limited number of experimental data were available then, and they only hinted at values of metal-silicate D's at high PT conditions. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements. At the same time several different models have been advanced to explain the siderophile elements in the earth's mantle: a) intermediate depth magma ocean; 25-30 GPa, b) deep magma ocean; up to 50 GPa, and c) early reduced and later oxidized magma ocean. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to update the predictive expressions outlined by Righter et al. (1997) with new experimental data from the last decade, test the predictive ability of these expressions against independent datasets (there are more data now to do this properly), and to apply the resulting expressions to the siderophile element patterns in Earth's upper mantle. The predictive expressions have the form: lnD = alnfO2 + b/T + cP/T + d(1Xs) + e(1Xc) + SigmafiXi + g These expressions are guided by the thermodynamics of simple metal-oxide equilibria that control each element, include terms that mimic the activity coefficients of each element in the metal and silicate, and quantify the effect of

  17. The Deep Hot Biosphere

    NASA Astrophysics Data System (ADS)

    Craig, Harmon

    The first inhabitants of planet Earth were single-celled microorganisms and they are still with us today. Their name is truly legion, for they live everywhere, from boiling hot springs at the Earth's surface and on the seafloor to the coldest waters of the oceans and the Antarctic lakes. They are the masters of evolutionary adaptation, who have colonized the entire range of conditions under which water can exist as a liquid. At some ancient mythic time billions of years ago in a witches' brew of precursory molecules, somewhere, somehow, on a sunny Precambrian day bright with promise some of these molecules came together in the first coupling, learned to replicate, create enzymes, metabolize, and seal themselves into protective membranes inside of which they began the process of living. How they did this is our greatest mystery, for they are our primordial ancestors and we do not understand ourselves until we understand them.

  18. TRUEX hot demonstration

    SciTech Connect

    Chamberlain, D.B.; Leonard, R.A.; Hoh, J.C.; Gay, E.C.; Kalina, D.G.; Vandegrift, G.F.

    1990-04-01

    In FY 1987, a program was initiated to demonstrate technology for recovering transuranic (TRU) elements from defense wastes. This hot demonstration was to be carried out with solution from the dissolution of irradiated fuels. This recovery would be accomplished with both PUREX and TRUEX solvent extraction processes. Work planned for this program included preparation of a shielded-cell facility for the receipt and storage of spent fuel from commercial power reactors, dissolution of this fuel, operation of a PUREX process to produce specific feeds for the TRUEX process, operation of a TRUEX process to remove residual actinide elements from PUREX process raffinates, and processing and disposal of waste and product streams. This report documents the work completed in planning and starting up this program. It is meant to serve as a guide for anyone planning similar demonstrations of TRUEX or other solvent extraction processing in a shielded-cell facility.

  19. Response of hot nuclei

    SciTech Connect

    Broglia, R.A.

    1986-01-01

    The dipole giant resonance is reviewed, as it is the only vibration which has been experimentally identified in the decay of hot nuclei. The mechanism of exciting the resonance and the mode of the resonance are described. The methods used to calculate the vibrations from the shell model are discussed, including the Hartree-Fock approximation and random phase approximation. Nuclei formed by compound nuclear reactions, which possess high excitation energy and angular momentum, are considered. It is argued that the stability of the dipole may be used to advantage in the study of other properties of nuclei at high excitation. It is also considered possible that the discussion of the dipole giant resonance may be extended to the gamma decay of the isovector quadrupole vibration. 26 refs., 18 figs. (LEW)

  20. Plasmon-induced hot carrier science and technology

    NASA Astrophysics Data System (ADS)

    Brongersma, Mark L.; Halas, Naomi J.; Nordlander, Peter

    2015-01-01

    The discovery of the photoelectric effect by Heinrich Hertz in 1887 set the foundation for over 125 years of hot carrier science and technology. In the early 1900s it played a critical role in the development of quantum mechanics, but even today the unique properties of these energetic, hot carriers offer new and exciting opportunities for fundamental research and applications. Measurement of the kinetic energy and momentum of photoejected hot electrons can provide valuable information on the electronic structure of materials. The heat generated by hot carriers can be harvested to drive a wide range of physical and chemical processes. Their kinetic energy can be used to harvest solar energy or create sensitive photodetectors and spectrometers. Photoejected charges can also be used to electrically dope two-dimensional materials. Plasmon excitations in metallic nanostructures can be engineered to enhance and provide valuable control over the emission of hot carriers. This Review discusses recent advances in the understanding and application of plasmon-induced hot carrier generation and highlights some of the exciting new directions for the field.

  1. Plasmon-induced hot carrier science and technology.

    PubMed

    Brongersma, Mark L; Halas, Naomi J; Nordlander, Peter

    2015-01-01

    The discovery of the photoelectric effect by Heinrich Hertz in 1887 set the foundation for over 125 years of hot carrier science and technology. In the early 1900s it played a critical role in the development of quantum mechanics, but even today the unique properties of these energetic, hot carriers offer new and exciting opportunities for fundamental research and applications. Measurement of the kinetic energy and momentum of photoejected hot electrons can provide valuable information on the electronic structure of materials. The heat generated by hot carriers can be harvested to drive a wide range of physical and chemical processes. Their kinetic energy can be used to harvest solar energy or create sensitive photodetectors and spectrometers. Photoejected charges can also be used to electrically dope two-dimensional materials. Plasmon excitations in metallic nanostructures can be engineered to enhance and provide valuable control over the emission of hot carriers. This Review discusses recent advances in the understanding and application of plasmon-induced hot carrier generation and highlights some of the exciting new directions for the field. PMID:25559968

  2. Plasmon-induced hot carrier science and technology.

    PubMed

    Brongersma, Mark L; Halas, Naomi J; Nordlander, Peter

    2015-01-01

    The discovery of the photoelectric effect by Heinrich Hertz in 1887 set the foundation for over 125 years of hot carrier science and technology. In the early 1900s it played a critical role in the development of quantum mechanics, but even today the unique properties of these energetic, hot carriers offer new and exciting opportunities for fundamental research and applications. Measurement of the kinetic energy and momentum of photoejected hot electrons can provide valuable information on the electronic structure of materials. The heat generated by hot carriers can be harvested to drive a wide range of physical and chemical processes. Their kinetic energy can be used to harvest solar energy or create sensitive photodetectors and spectrometers. Photoejected charges can also be used to electrically dope two-dimensional materials. Plasmon excitations in metallic nanostructures can be engineered to enhance and provide valuable control over the emission of hot carriers. This Review discusses recent advances in the understanding and application of plasmon-induced hot carrier generation and highlights some of the exciting new directions for the field.

  3. Hot hollow cathode gun assembly

    DOEpatents

    Zeren, J.D.

    1983-11-22

    A hot hollow cathode deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, the hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  4. Hot-electron-mediated surface chemistry: toward electronic control of catalytic activity.

    PubMed

    Park, Jeong Young; Kim, Sun Mi; Lee, Hyosun; Nedrygailov, Ievgen I

    2015-08-18

    Energy dissipation at surfaces and interfaces is mediated by excitation of elementary processes, including phonons and electronic excitation, once external energy is deposited to the surface during exothermic chemical processes. Nonadiabatic electronic excitation in exothermic catalytic reactions results in the flow of energetic electrons with an energy of 1-3 eV when chemical energy is converted to electron flow on a short (femtosecond) time scale before atomic vibration adiabatically dissipates the energy (in picoseconds). These energetic electrons that are not in thermal equilibrium with the metal atoms are called "hot electrons". The detection of hot electron flow under atomic or molecular processes and understanding its role in chemical reactions have been major topics in surface chemistry. Recent studies have demonstrated electronic excitation produced during atomic or molecular processes on surfaces, and the influence of hot electrons on atomic and molecular processes. We outline research efforts aimed at identification of the intrinsic relation between the flow of hot electrons and catalytic reactions. We show various strategies for detection and use of hot electrons generated by the energy dissipation processes in surface chemical reactions and photon absorption. A Schottky barrier localized at the metal-oxide interface of either catalytic nanodiodes or hybrid nanocatalysts allows hot electrons to irreversibly transport through the interface. We show that the chemicurrent, composed of hot electrons excited by the surface reaction of CO oxidation or hydrogen oxidation, correlates well with the turnover rate measured separately by gas chromatography. Furthermore, we show that hot electron flows generated on a gold thin film by photon absorption (or internal photoemission) can be amplified by localized surface plasmon resonance. The influence of hot charge carriers on the chemistry at the metal-oxide interface are discussed for the cases of Au, Ag, and Pt

  5. Hot-electron-mediated surface chemistry: toward electronic control of catalytic activity.

    PubMed

    Park, Jeong Young; Kim, Sun Mi; Lee, Hyosun; Nedrygailov, Ievgen I

    2015-08-18

    Energy dissipation at surfaces and interfaces is mediated by excitation of elementary processes, including phonons and electronic excitation, once external energy is deposited to the surface during exothermic chemical processes. Nonadiabatic electronic excitation in exothermic catalytic reactions results in the flow of energetic electrons with an energy of 1-3 eV when chemical energy is converted to electron flow on a short (femtosecond) time scale before atomic vibration adiabatically dissipates the energy (in picoseconds). These energetic electrons that are not in thermal equilibrium with the metal atoms are called "hot electrons". The detection of hot electron flow under atomic or molecular processes and understanding its role in chemical reactions have been major topics in surface chemistry. Recent studies have demonstrated electronic excitation produced during atomic or molecular processes on surfaces, and the influence of hot electrons on atomic and molecular processes. We outline research efforts aimed at identification of the intrinsic relation between the flow of hot electrons and catalytic reactions. We show various strategies for detection and use of hot electrons generated by the energy dissipation processes in surface chemical reactions and photon absorption. A Schottky barrier localized at the metal-oxide interface of either catalytic nanodiodes or hybrid nanocatalysts allows hot electrons to irreversibly transport through the interface. We show that the chemicurrent, composed of hot electrons excited by the surface reaction of CO oxidation or hydrogen oxidation, correlates well with the turnover rate measured separately by gas chromatography. Furthermore, we show that hot electron flows generated on a gold thin film by photon absorption (or internal photoemission) can be amplified by localized surface plasmon resonance. The influence of hot charge carriers on the chemistry at the metal-oxide interface are discussed for the cases of Au, Ag, and Pt

  6. Hot Spot Cosmic Accelerators

    NASA Astrophysics Data System (ADS)

    2002-11-01

    length of more than 3 million light-years, or no less than one-and-a-half times the distance from the Milky Way to the Andromeda galaxy, this structure is indeed gigantic. The region where the jets collide with the intergalactic medium are known as " hot spots ". Superposing the intensity contours of the radio emission from the southern "hot spot" on a near-infrared J-band (wavelength 1.25 µm) VLT ISAAC image ("b") shows three distinct emitting areas; they are even better visible on the I-band (0.9 µm) FORS1 image ("c"). This emission is obviously associated with the shock front visible on the radio image. This is one of the first times it has been possible to obtain an optical/near-IR image of synchrotron emission from such an intergalactic shock and, thanks to the sensitivity and image sharpness of the VLT, the most detailed view of its kind so far . The central area (with the strongest emission) is where the plasma jet from the galaxy centre hits the intergalactic medium. The light from the two other "knots", some 10 - 15,000 light-years away from the central "hot spot", is also interpreted as synchrotron emission. However, in view of the large distance, the astronomers are convinced that it must be caused by electrons accelerated in secondary processes at those sites . The new images thus confirm that electrons are being continuously accelerated in these "knots" - hence called "cosmic accelerators" - far from the galaxy and the main jets, and in nearly empty space. The exact physical circumstances of this effect are not well known and will be the subject of further investigations. The present VLT-images of the "hot spots" near 3C 445 may not have the same public appeal as some of those beautiful images that have been produced by the same instruments during the past years. But they are not less valuable - their unusual importance is of a different kind, as they now herald the advent of fundamentally new insights into the mysteries of this class of remote and active

  7. Practical hot oiling and hot watering for paraffin control

    SciTech Connect

    Mansure, A.J.; Barker, K.M.

    1994-03-01

    One of the common oil-field wellbore problems is paraffin deposition. Even though hot oiling or hot watering is usually the first method tried for removing paraffin, few operators appreciate the limitations of ``hot oiling`` and the potential for the fluid to aggravate well problems and cause formation damage. Field tests have shown that the chemical and thermal processes that occur during ``hot oiling`` are very complex and that there are significant variations in practices among operators. Key issues include: (1) During a typical hot oiling job, a significant amount of the fluid injected into the well goes into the formation, and hence, particulates and chemicals in the fluid have the potential to damage the formation. (2) Hot oiling can vaporize oil in the tubing faster than the pump lifts oil. This interrupts paraffin removal from the well, and thus the wax is refined into harder deposits, goes deeper into the well, and can stick rods. These insights have been used to determine good ``hot oiling`` practices designed to maximize wax removal and minimize formation damage.

  8. Really Hot Stars

    NASA Astrophysics Data System (ADS)

    2003-04-01

    Spectacular VLT Photos Unveil Mysterious Nebulae Summary Quite a few of the most beautiful objects in the Universe are still shrouded in mystery. Even though most of the nebulae of gas and dust in our vicinity are now rather well understood, there are some which continue to puzzle astronomers. This is the case of a small number of unusual nebulae that appear to be the subject of strong heating - in astronomical terminology, they present an amazingly "high degree of excitation". This is because they contain significant amounts of ions, i.e., atoms that have lost one or more of their electrons. Depending on the atoms involved and the number of electrons lost, this process bears witness to the strength of the radiation or to the impact of energetic particles. But what are the sources of that excitation? Could it be energetic stars or perhaps some kind of exotic objects inside these nebulae? How do these peculiar objects fit into the current picture of universal evolution? New observations of a number of such unusual nebulae have recently been obtained with the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). In a dedicated search for the origin of their individual characteristics, a team of astronomers - mostly from the Institute of Astrophysics & Geophysics in Liège (Belgium) [1] - have secured the first detailed, highly revealing images of four highly ionized nebulae in the Magellanic Clouds, two small satellite galaxies of our home galaxy, the Milky Way, only a few hundred thousand light-years away. In three nebulae, they succeeded in identifying the sources of energetic radiation and to eludicate their exceptional properties: some of the hottest, most massive stars ever seen, some of which are double. With masses of more than 20 times that of the Sun and surface temperatures above 90 000 degrees, these stars are truly extreme. PR Photo 09a/03: Nebula around the hot star AB7 in the SMC. PR Photo 09b/03: Nebula near the hot Wolf-Rayet star BAT99

  9. Detecting the Warm-Hot IGM via Ultraviolet Absorbers

    NASA Astrophysics Data System (ADS)

    Danforth, Charles

    2010-03-01

    Detecting the Warm-Hot Intergalactic Medium (WHIM, T=105-107 K) via X-ray absorption in highly-ionized metal ions is a major goal in X-ray astronomy today. Species such as OVII and OVIII are predicted to be present in large quantities in the IGM, tracing metal-enriched diffuse gas at T>106 K. This reservoir of WHIM may make up a substantial fraction of the "missing" baryons in the low-redshift universe, however detections from Chandra and XMM-Newton been few and controversial. In the mean time, alternate methods of detecting the WHIM via far-UV absorbers are yielding impressive results. Roughly 100 highly-ionized metal ion detections (OVI, NV, etc) trace enriched, shock-heated gas at T<106 K. The catalog of far-UV WHIM absorbers is now large enough to not only detect the WHIM, but to start statistically-meaningful investigations as to its nature, origin, and distribution. Thermally-broadened Lyman-alpha absorbers are a second avenue of WHIM investigation which is similarly starting to produce results. Unlike either X-ray or UV metal line surveys, broad Lya studies are independent of metal enrichment and thus can trace hot gas in low-metallicity voids. Together, these two UV spectroscopic methods can account for 20% of the local baryons in the local universe.

  10. Hot Hydrogen Test Facility

    SciTech Connect

    W. David Swank

    2007-02-01

    The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISp. This quantity is proportional to the square root of the propellant’s absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500°C hydrogen flowing at 1500 liters per minute. The facility is intended to test non-uranium containing materials and therefore is particularly suited for testing potential cladding and coating materials. In this first installment the facility is described. Automated Data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

  11. Hot Hydrogen Test Facility

    SciTech Connect

    Swank, W. David; Carmack, Jon; Werner, James E.; Pink, Robert J.; Haggard, DeLon C.; Johnson, Ryan

    2007-01-30

    The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISP. This quantity is proportional to the square root of the propellant's absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500 deg. C hydrogen flowing at 1500 liters per minute. The facility is intended to test low activity uranium containing materials but is also suited for testing cladding and coating materials. In this first installment the facility is described. Automated data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

  12. Saturn's Hot Spot

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This is the sharpest image of Saturn's temperature emissions taken from the ground; it is a mosaic of 35 individual exposures made at the W.M. Keck I Observatory, Mauna Kea, Hawaii on Feb. 4, 2004.

    The images to create this mosaic were taken with infrared radiation. The mosaic was taken at a wavelength near 17.65 microns and is sensitive to temperatures in Saturn's upper troposphere. The prominent hot spot at the bottom of the image is right at Saturn's south pole. The warming of the southern hemisphere was expected, as Saturn was just past southern summer solstice, but the abrupt changes in temperature with latitude were not expected. The tropospheric temperature increases toward the pole abruptly near 70 degrees latitude from 88 to 89 Kelvin (-301 to -299 degrees Fahrenheit) and then to 91 Kelvin (-296 degrees Fahrenheit) right at the pole.

    Ring particles are not at a uniform temperature everywhere in their orbit around Saturn. The ring particles are orbiting clockwise in this image. Particles are coldest just after having cooled down in Saturn's shadow (lower left). As they orbit Saturn, the particles increase in temperature up to a maximum (lower right) just before passing behind Saturn again in shadow.

    A small section of the ring image is missing because of incomplete mosaic coverage during the observing sequence.

  13. Really Hot Stars

    NASA Astrophysics Data System (ADS)

    2003-04-01

    Spectacular VLT Photos Unveil Mysterious Nebulae Summary Quite a few of the most beautiful objects in the Universe are still shrouded in mystery. Even though most of the nebulae of gas and dust in our vicinity are now rather well understood, there are some which continue to puzzle astronomers. This is the case of a small number of unusual nebulae that appear to be the subject of strong heating - in astronomical terminology, they present an amazingly "high degree of excitation". This is because they contain significant amounts of ions, i.e., atoms that have lost one or more of their electrons. Depending on the atoms involved and the number of electrons lost, this process bears witness to the strength of the radiation or to the impact of energetic particles. But what are the sources of that excitation? Could it be energetic stars or perhaps some kind of exotic objects inside these nebulae? How do these peculiar objects fit into the current picture of universal evolution? New observations of a number of such unusual nebulae have recently been obtained with the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). In a dedicated search for the origin of their individual characteristics, a team of astronomers - mostly from the Institute of Astrophysics & Geophysics in Liège (Belgium) [1] - have secured the first detailed, highly revealing images of four highly ionized nebulae in the Magellanic Clouds, two small satellite galaxies of our home galaxy, the Milky Way, only a few hundred thousand light-years away. In three nebulae, they succeeded in identifying the sources of energetic radiation and to eludicate their exceptional properties: some of the hottest, most massive stars ever seen, some of which are double. With masses of more than 20 times that of the Sun and surface temperatures above 90 000 degrees, these stars are truly extreme. PR Photo 09a/03: Nebula around the hot star AB7 in the SMC. PR Photo 09b/03: Nebula near the hot Wolf-Rayet star BAT99

  14. Neptune's 'Hot' South Pole

    NASA Technical Reports Server (NTRS)

    2007-01-01

    These thermal images show a 'hot' south pole on the planet Neptune. These warmer temperatures provide an avenue for methane to escape out of the deep atmosphere.

    The images were obtained with the Very Large Telescope in Chile, using an imager/spectrometer for mid-infrared wavelengths on Sept. 1 and 2, 2006. The telescope is operated by the European Organization for Astronomical Research in the Southern Hemisphere (known as ESO).

    Scientists say Neptune's south pole is 'hotter' than anywhere else on the planet by about 10 degrees Celsius (50 degrees Fahrenheit). The average temperature on Neptune is about minus 200 degrees Celsius (minus 392 degrees Fahrenheit).

    The upper left image samples temperatures near the top of Neptune's troposphere (near 100 millibar pressure, which is one-tenth the Earth atmospheric pressure at sea level). The hottest temperatures are indicated at the lower part of the image, at Neptune's south pole (see the graphic at the upper right). The lower two images, taken 6.3 hours apart, sample temperatures at higher altitudes in Neptune's stratosphere. They do show generally warmer temperatures near, but not at, the south pole. They also show a distinct warm area which can be seen in the lower left image and rotated completely around the back of the planet and returned to the earth-facing hemisphere in the lower right image.

  15. Techniques for hot structures testing

    NASA Technical Reports Server (NTRS)

    Deangelis, V. Michael; Fields, Roger A.

    1990-01-01

    Hot structures testing have been going on since the early 1960's beginning with the Mach 6, X-15 airplane. Early hot structures test programs at NASA-Ames-Dryden focused on operational testing required to support the X-15 flight test program, and early hot structures research projects focused on developing lab test techniques to simulate flight thermal profiles. More recent efforts involved numerous large and small hot structures test programs that served to develop test methods and measurement techniques to provide data that promoted the correlation of test data with results from analytical codes. In Nov. 1988 a workshop was sponsored that focused on the correlation of hot structures test data with analysis. Limited material is drawn from the workshop and a more formal documentation is provided of topics that focus on hot structures test techniques used at NASA-Ames-Dryden. Topics covered include the data acquisition and control of testing, the quartz lamp heater systems, current strain and temperature sensors, and hot structures test techniques used to simulate the flight thermal environment in the lab.

  16. Hot dry rock reservoir engineering

    SciTech Connect

    Murphy, H.

    1987-01-01

    The Hot Dry Rock (HDR) concept is a simple one. Two nearly parallel wells are drilled, and hydraulic fractures are then formed to hydraulically connect the wells. Water pumped down the injection well and through the fracture system is heated by contact with the hot rock and rises to the production well. This hot fluid is passed through a heat exchanger at the surface and the extracted heat is used for direct heating or electricity generation. The cooled production fluid is then reinjected, thereby setting up a circulation loop. This paper describes the development and execution of the HDR project at Fenton Hill, New Mexico.

  17. Not so hot "hot spots" in the oceanic mantle.

    PubMed

    Bonath, E

    1990-10-01

    Excess volcanism and crustal swelling associated with hot spots are generally attributed to thermal plumes upwelling from the mantle. This concept has been tested in the portion of the Mid-Atlantic Ridge between 34 degrees and 45 degrees (Azores hot spot). Peridotite and basalt data indicate that the upper mantle in the hot spot has undergone a high degree of melting relative to the mantle elsewhere in the North Atlantic. However, application of various geothermometers suggests that the temperature of equilibration of peridotites in the mantle was lower, or at least not higher, in the hot spot than elsewhere. The presence of H(2)O-rich metasomatized mantle domains, inferred from peridotite and basalt data, would lower the melting temperature of the hot spot mantle and thereby reconcile its high degree ofmelting with the lack of a mantle temperature anomaly. Thus, some so-called hot spots might be melting anomalies unrelated to abnormally high mantle temperature or thermal plumes. PMID:17808242

  18. Hierarchical nonlinear behavior of hot composite structures

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Chamis, C. C.; Singhal, S. N.

    1993-01-01

    Hierarchical computational procedures are described to simulate the multiple scale thermal/mechanical behavior of high temperature metal matrix composites (HT-MMC) in the following three broad areas: (1) behavior of HT-MMC's from micromechanics to laminate via METCAN (Metal Matrix Composite Analyzer), (2) tailoring of HT-MMC behavior for optimum specific performance via MMLT (Metal Matrix Laminate Tailoring), and (3) HT-MMC structural response for hot structural components via HITCAN (High Temperature Composite Analyzer). Representative results from each area are presented to illustrate the effectiveness of computational simulation procedures and accompanying computer codes. The sample case results show that METCAN can be used to simulate material behavior such as the entire creep span; MMLT can be used to concurrently tailor the fabrication process and the interphase layer for optimum performance such as minimum residual stresses; and HITCAN can be used to predict the structural behavior such as the deformed shape due to component fabrication. These codes constitute virtual portable desk-top test laboratories for characterizing HT-MMC laminates, tailoring the fabrication process, and qualifying structural components made from them.

  19. Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14Cr15Y2C15B6 and W-Containing Variants

    SciTech Connect

    Farmer, J C; Haslam, J; Day, S; Lian, T; Saw, C; Hailey, P; Choi, J; Yang, N; Blue, C; Peter, W; Payer, J; Branagan, D J

    2006-10-20

    Yttrium-containing SAM1651 (Fe{sub 48.0}Cr{sub 15.0}Mo{sub 14.0}B{sub 6.0}C{sub 15.0}Y{sub 2.0}), has a critical cooling rate (CCR) of approximately 80 Kelvin per second, while SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) with no yttrium has a higher critical cooling rate of approximately 600 Kelvin per second. SAM1651's low CCR enables it to be rendered as a completely amorphous material in practical materials processes. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The passive film stability of these Fe-based amorphous metal formulations have been found to be superior to that of conventional stainless steels, and comparable to that of Ni-based alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates.

  20. METAL COATING BATHS

    DOEpatents

    Robinson, J.W.

    1958-08-26

    A method is presented for restoring the effectiveness of bronze coating baths used for hot dip coating of uranium. Such baths, containing a high proportion of copper, lose their ability to wet uranium surfaces after a period of use. The ability of such a bath to wet uranium can be restored by adding a small amount of metallic aluminum to the bath, and skimming the resultant hard alloy from the surface.

  1. Red-Hot Saturn

    NASA Technical Reports Server (NTRS)

    2005-01-01

    These side-by-side false-color images show Saturn's heat emission. The data were taken on Feb. 4, 2004, from the W. M. Keck I Observatory, Mauna Kea, Hawaii. Both images were taken with infrared radiation. The image on the left was taken at a wavelength near 17.65 microns and is sensitive to temperatures in Saturn's upper troposphere. The image on the right was taken at a wavelength of 8 microns and is sensitive to temperatures in Saturn's stratosphere. The prominent hot spot at the bottom of each image is at Saturn's south pole. The warming of the southern hemisphere was expected, as Saturn was just past southern summer solstice, but the abrupt changes in temperature with latitude were not expected.

    The troposphere temperature increases toward the pole abruptly near 70 degrees latitude from 88 to 89 Kelvin (-301 to -299 degrees Fahrenheit) and then to 91 Kelvin (-296 degrees Fahrenheit) right at the pole. Near 70 degrees latitude, the stratospheric temperature increases even more abruptly from 146 to 150 Kelvin (-197 to -189 degrees Fahrenheit) and then again to 151 Kelvin (-188 degrees Fahrenheit) right at the pole.

    While the rings are too faint to be detected at 8 microns (right), they show up at 17.65 microns. The ring particles are orbiting Saturn to the left on the bottom and to the right on the top. The lower left ring is colder than the lower right ring, because the particles are just moving out of Saturn's shadow where they have cooled off. As they orbit Saturn, they warm up to a maximum just before passing behind Saturn again in shadow.

  2. A deep XMM-Newton study of the hot gaseous halo around NGC 1961

    NASA Astrophysics Data System (ADS)

    Anderson, Michael E.; Churazov, Eugene; Bregman, Joel N.

    2016-01-01

    We examine 11 XMM-Newton observations of the giant spiral galaxy NGC 1961, allowing us to study the hot gaseous halo of a spiral galaxy in unprecedented detail. We perform a spatial and a spectral analysis; with the former, the hot halo is detected to at least 80 kpc and with the latter its properties can be measured in detail up to 42 kpc. We find evidence for a negative gradient in the temperature profile as is common for elliptical galaxies. We measure a rough metallicity profile, which is consistent with being flat at Z ˜ 0.2 Z⊙. Converting to this metallicity, the deprojected density profile is consistent with previous parametric fits, with no evidence for a break within 42 kpc (˜0.1 Rvir). Extrapolating to the virial radius, we infer a hot halo mass comparable to the stellar mass of the galaxy, and a baryon fraction from the stars and hot gas of around 30 per cent. The cooling time of the hot gas is orders of magnitude longer than the dynamical time, making the hot halo stable against cooling instabilities, and we argue that an extended stream of neutral hydrogen seen to the NW of this galaxy is instead likely due to accretion from the intergalactic medium. The low metallicity of the hot halo suggests that it too was likely accreted. We compare the hot halo of NGC 1961 to hot haloes around isolated elliptical galaxies, and show that the total mass determines the hot halo properties better than the stellar mass.

  3. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  4. Hard metal composition

    DOEpatents

    Sheinberg, Haskell

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  5. Morpheus Lander Hot Fire Test

    NASA Video Gallery

    This video shows a successful "hot fire" test of the Morpheus lander on February 27, 2012, at the VTB Flight Complex at NASA's Johnson Space Center. The engine burns for an extended period of time ...

  6. Coulomb explosion of "hot spot"

    NASA Astrophysics Data System (ADS)

    Oreshkin, V. I.; Oreshkin, E. V.; Chaikovsky, S. A.; Artyomov, A. P.

    2016-09-01

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  7. Quantitative spectroscopy of hot stars

    NASA Technical Reports Server (NTRS)

    Kudritzki, R. P.; Hummer, D. G.

    1990-01-01

    A review on the quantitative spectroscopy (QS) of hot stars is presented, with particular attention given to the study of photospheres, optically thin winds, unified model atmospheres, and stars with optically thick winds. It is concluded that the results presented here demonstrate the reliability of Qs as a unique source of accurate values of the global parameters (effective temperature, surface gravity, and elemental abundances) of hot stars.

  8. Strategies for detecting the missing hot baryons in the universe

    NASA Astrophysics Data System (ADS)

    Bregman, Joel N.; Alves, Guilherme Camargo; Miller, Matthew J.; Hodges-Kluck, Edmund

    2015-10-01

    About 30% to 50% of the baryons in the local universe are unaccounted for and are likely in a hot phase, 105.5 to 108 K. A hot halo (106.3 K) is detected around the Milky Way through the O VII and O VIII resonance absorption and emission lines in the soft x-ray band. Current instruments are not sensitive enough to detect this gas in absorption around other galaxies and galaxy groups, the two most likely sites. We show that resonant line absorption by this hot gas can be detected with current technology, with a collecting area exceeding ˜300 cm2 and a spectral resolution R>2000. For a few notional x-ray telescope configurations that could be constructed as Explorer or Probe missions, we calculate the differential number of O VII and O VIII absorbers as a function of equivalent width through redshift space, dN/dz. The hot halos of individual external galaxies produce absorption that should be detectable out to about their virial radii. For the Milky Way, one can determine the radial distribution of density, temperature, and metallicity after making optical depth corrections. Spectroscopic observations can determine the rotation of a hot gaseous halo.

  9. Are many hot subdwarf stars hidden in binaries?

    NASA Astrophysics Data System (ADS)

    Wade, Richard

    The Palomar-Green (PG) survey of UV-excess objects yielded an abundant harvest of hot subdwarf (sdO/sdB) stars. Based on visual and near IR (2MASS) colors, about one-third of these are binary (composite colors). Many additional candidate PG stars that might also be hot subdwarfs in binaries were rejected from the final PG catalog, because the Ca II K line appears in their spectra; this line was interpreted to mean that the candidates are cool metal-poor stars (sdF) with low UV line-blocking, so they were U-B color-selected for the wrong reason. An alternate explanation is that these objects are additional composite-spectrum binaries consisting of a hot subdwarf and a main sequence (A or F) star. Optical data alone cannot easily distinguish between these possibilities. A recent theory of binary sdB formation channels predicts that many sdB+A/F systems exist undiscovered, and the rejected PG stars are pointed to as a specific example of where they might be found. With a targeted archival study using GALEX imaging data to search for radiation from a hot star, we can learn whether or not these rejected objects from the PG survey are in fact mostly sdB binaries, with consequences for the origin and numbers of hot evolved stars.

  10. Multi-stage FE simulation of hot ring rolling

    NASA Astrophysics Data System (ADS)

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

    2013-05-01

    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

  11. Hot Films on Ceramic Substrates for Measuring Skin Friction

    NASA Technical Reports Server (NTRS)

    Noffz, Greg; Leiser, Daniel; Bartlett, Jim; Lavine, Adrienne

    2003-01-01

    Hot-film sensors, consisting of a metallic film on an electrically nonconductive substrate, have been used to measure skin friction as far back as 1931. A hot film is maintained at an elevated temperature relative to the local flow by passing an electrical current through it. The power required to maintain the specified temperature depends on the rate at which heat is transferred to the flow. The heat transfer rate correlates to the velocity gradient at the surface, and hence, with skin friction. The hot-film skin friction measurement method is most thoroughly developed for steady-state conditions, but additional issues arise under transient conditions. Fabricating hot-film substrates using low-thermal-conductivity ceramics can offer advantages over traditional quartz or polyester-film substrates. First, a low conductivity substrate increases the fraction of heat convected away by the fluid, thus increasing sensitivity to changes in flow conditions. Furthermore, the two-part, composite nature of the substrate allows the installation of thermocouple junctions just below the hot film, which can provide an estimate of the conduction heat loss.

  12. THE HOT INTERSTELLAR MEDIUM OF THE INTERACTING GALAXY NGC 4490

    SciTech Connect

    Richings, A. J.; Fabbiano, G.; Wang Junfeng; Roberts, T. P.

    2010-11-10

    We present an analysis of the hot interstellar medium (ISM) in the spiral galaxy NGC 4490, which is interacting with the irregular galaxy NGC 4485, using {approx}100 ks of Chandra ACIS-S observations. The high angular resolution of Chandra enables us to remove discrete sources and perform spatially resolved spectroscopy for the star-forming regions and associated outflows, allowing us to look at how the physical properties of the hot ISM such as temperature, hydrogen column density, and metal abundances vary throughout these galaxies. We find temperatures of >0.41 keV and 0.85{sup +0.59}{sub -0.12} keV, electron densities of >1.87{eta}{sup -1/2} x 10{sup -3} cm{sup -3} and 0.21{sup +0.03}{sub -0.04{eta}}{sup -1/2} x 10{sup -3} cm{sup -3}, and hot gas masses of >1.1{eta}{sup 1/2} x 10{sup 7} M{sub sun} and {approx}3.7{eta}{sup 1/2} x 10{sup 7} M{sub sun} in the plane and halo of NGC 4490, respectively, where {eta} is the filling factor of the hot gas. The abundance ratios of Ne, Mg, and Si with respect to Fe are found to be consistent with those predicted by theoretical models of type II supernovae (SNe). The thermal energy in the hot ISM is {approx}5% of the total mechanical energy input from SNe, so it is likely that the hot ISM has been enriched and heated by type II SNe. The X-ray emission is anticorrelated with the H{alpha} and mid-infrared emission, suggesting that the hot gas is bounded by filaments of cooler ionized hydrogen mixed with warm dust.

  13. Hot isostatic pressing of titanium based materials

    SciTech Connect

    Froes, F.H.; Widmer, R.; Hebeisen, J.

    1996-12-31

    The importance of titanium in demanding aerospace and terrestrial applications is presented, and the necessity to reduce cost to increase use is discussed. Hot isostatic pressing (HIP`ing) can be utilized with titanium based materials to obtain cost reduction and to enhance performance. The science/technology of various facets of the titanium scenario where HIP`ing can be used to advantage is presented, including powder metallurgy, castings, metal matrix composites and use of thermochemical processing. The major application of HIP`ing for titanium based materials is in castings; followed by blended elemental concepts. Much work has been conducted on continuous fiber reinforced materials, with the first use in actual commercial components likely to occur in engine components. Discontinuously reinforced products are already in use in aerospace and terrestrial applications. For the future, developing processing such as mechanical alloying, nanostructured materials and rapidly solidified product could benefit from compaction by HIP`ing. 55 refs., 30 figs.

  14. Glass Coats For Hot Isostatic Pressing

    NASA Technical Reports Server (NTRS)

    Ecer, Gunes M.

    1989-01-01

    Surface voids sealed from pressurizing gas. Coating technique enables healing of surface defects by hot isostatic pressing (HIP). Internal pores readily closed by HIP, but surface voids like cracks and pores in contact with pressurizing gas not healed. Applied to casting or weldment as thick slurry of two glass powders: one melts at temperature slightly lower than used for HIP, and another melts at higher temperature. For example, powder is glass of 75 percent SiO2 and 25 percent Na2O, while other powder SiO2. Liquid component of slurry fugitive organic binder; for example, mixture of cellulose acetate and acetone. Easy to apply, separates voids from surrounding gas, would not react with metal part under treatment, and easy to remove after pressing.

  15. Mechanism of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Meier, G. H.

    1982-01-01

    The Na2SO4 - induced hot corrosion of IN-738 in the temperature range 900 C to 1000 C is characterized by an initiation stage during which the corrosion rate is slow followed by a propagation stage during which the corrosion rate is markedly accelerated. In the second stage, corrosion is accelerated due essentially to a sulfidation/oxidation mechanism; in the third stage, the rate becomes catastrophic due to acid fluxing induced by an accumulation of refractory metal oxides (particularly MoO3) in the Na2SO4. The sequential stages in the corrosion process are described and a mechanism proposed. The influence of alloy microstructure on the corrosion mechanism is also discussed.

  16. Ultrafast demagnetization by hot electrons: Diffusion or super-diffusion?

    PubMed Central

    Salvatella, G.; Gort, R.; Bühlmann, K.; Däster, S.; Vaterlaus, A.; Acremann, Y.

    2016-01-01

    Ultrafast demagnetization of ferromagnetic metals can be achieved by a heat pulse propagating in the electron gas of a non-magnetic metal layer, which absorbs a pump laser pulse. Demagnetization by electronic heating is investigated on samples with different thicknesses of the absorber layer on nickel. This allows us to separate the contribution of thermalized hot electrons compared to non-thermal electrons. An analytical model describes the demagnetization amplitude as a function of the absorber thickness. The observed change of demagnetization time can be reproduced by diffusive heat transport through the absorber layer.

  17. Hot on the inside.

    PubMed

    Weinmann, Michael

    2003-07-01

    When a disease process becomes life-threatening, it is termed to be malignant. Hyperthermia is a heat illness that arises from one of two basic causes: 1) the body's normal thermoregulatory mechanisms are overwhelmed by the environment (an exogenous heat load) or, more commonly, by excessive exercise in a moderate-to-extreme environment (an endogenous heat load); or 2) failure of the thermoregulatory mechanisms, such as those encountered in the elderly or debilitated patient. Either cause can lead to heat illnesses such as heat cramps, heat exhaustion or heatstroke. Heat cramps are brief, intermittent and often severe muscular cramps that frequently occur in muscles fatigued by heavy work or exercise. They are believed to be caused by a rapid change in the extracellular fluid osmolarity resulting from sodium and water loss. Heat exhaustion is a more severe form of heat illness characterized by minor changes in mental status (poor judgment, irritability), dizziness, nausea and headache. In severe cases, the patient may have an altered LOC. Just as with heat cramps, profuse sweating is present. Removing the patient from the hot environment and administering fluids will usually result in a rapid recovery. [table: see text] Left untreated, heat exhaustion may progress to heatstroke. Heatstroke results when there is a complete collapse of thermoregulatory mechanisms. This will lead to a rise in body core temperature in excess of 105.8 degrees F (41 degrees C), which will produce multisystem tissue damage and physiological collapse. Severe cases can cause death. The patient in this case had an axillary temperature taken and recorded at 101.4 degrees F. Typically, axillary temperatures are one degree cooler than oral temperatures, which are one degree cooler than core temperatures. This patient, then, had a core temperature of 103 degrees F or higher. There are two types of heatstroke: classic and exertional. Classic heatstroke occurs during periods of sustained high

  18. Process for the disposal of alkali metals

    DOEpatents

    Lewis, Leroy C.

    1977-01-01

    Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level.

  19. Hot melt "corner point method" for attaching large plastic sections to glass slides.

    PubMed

    Krämer, K L; von Hagens, G

    1983-03-01

    We describe a fast method for firm attachment of large plastic sections to glass slides with EVA-copolymers, commonly known as hot melt sticks. Solid hot melt sticks dissolve slowly in xylene to form an adhesive gel within 6 hours. Small drops of hot melt gel are applied to the corners of the sections and surrounding slide surface at ambient or elevated temperatures. The gel sticks to both the plastic and the glass slides. The hot melt "corner point method" prevented detachment of sections in staining procedures. As an additional technique, we suggest the use of hot melt adhesive for attaching plastic specimen blocks to wooden blocks or metallic specimen holders. PMID:6353677

  20. Experimental Study of Ignition by Hot Spot in Internal Combustion Engines

    NASA Technical Reports Server (NTRS)

    Serruys, Max

    1938-01-01

    In order to carry out the contemplated study, it was first necessary to provide hot spots in the combustion chamber, which could be measured and whose temperature could be changed. It seemed difficult to realize both conditions working solely on the temperature of the cooling water in a way so as to produce hot spots on the cylinder wall capable of provoking autoignition. Moreover, in the majority of practical cases, autoignition is produced by the spark plug, one of the least cooled parts in the engine. The first procedure therefore did not resemble that which most generally occurs in actual engine operation. All of these considerations caused us to reproduce similar hot spots at the spark plugs. The hot spots produced were of two kinds and designated with the name of thermo-electric spark plug and of metallic hot spot.

  1. Multi-field coupled numerical simulation of hot reversible rolling process of GCr15 steel rod

    NASA Astrophysics Data System (ADS)

    Gu, Sendong; Zhang, Liwen; Ruan, Jinhua; Mei, Hongyu; Zhen, Yu; Shi, Xinhua

    2013-05-01

    In this paper, based on rolling technology of hot reversible rolling mill, a multi-filed coupled finite element (FE) model of hot reversible rolling process of large dimension cross-section GCr15 steel rod is established. Thermal, mechanical and microstructural phenomena during the rolling process are coupled in the model. By employing grain growth experiment, double and single hit hot compression experiments, the austenite grain size growth mathematical model and recrystallization behavior mathematical models are determined. And a designed subprogram is coupled in the FE model. Actual hot reversible rolling process of GCr15 steel is simulated using the model and the distribution and evolution of different filed-variables, such as temperature, effective strain and austenite grain size are obtained. To verify the model predictions, hot rolling experiments are carried out and the temperature and microstructure of the rolling metal are compared with the predicted results. The comparison between the two sets of data shows a good agreement.

  2. HOT CELL BUILDING, TRA632. EAST END OF BUILDING. CAMERA FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HOT CELL BUILDING, TRA-632. EAST END OF BUILDING. CAMERA FACING WEST. TRUCK ENCLOSURE (1986) TO THE LEFT, SMALL ADDITION IN ITS SHADOW IS ENCLOSURE OVER METAL PORT INTO HOT CELL NO. 1 (THE OLDEST HOT CELL). NOTE PERSONNEL LADDER AND PLATFORM AT LOFT LEVEL USED WHEN SERVICING AIR FILTERS AND VENTS OF CELL NO. 1. INL NEGATIVE NO. HD46-32-4. Mike Crane, Photographer, 4/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  3. A&M. Hot liquid waste treatment building (TAN616). Contextual view, facing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    A&M. Hot liquid waste treatment building (TAN-616). Contextual view, facing south. Wall of hot shop (TAN-607) with high bay at left of view. Lower-roofed building at left edge of view is TAN- 633, hot cell annex. Complex at center of view is TAN-616. Tall metal building with gable roof is TAN-615. Photographer: Ron Paarmann. Date: September 22, 1997. INEEL negative no. HD-20-2-2 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  4. Post-irradiation-examination of irradiated fuel outside the hot cell

    SciTech Connect

    Dawn E. Janney; Adam B. Robinson; Thomas P. O'Holleran; R. Paul Lind; Marc Babcock; Laurence C. Brower; Julie Jacobs; Pamela K. Hoggan

    2007-09-01

    Because of their high radioactivity, irradiated fuels are commonly examined in a hot cell. However, the Idaho National Laboratory (INL) has recently investigated irradiated U-Mo-Al metallic fuel from the Reduced Enrichment for Research and Test Reactors (RERTR) project using a conventional unshielded scanning electron microscope outside a hot cell. This examination was possible because of a two-step sample-preparation approach in which a small volume of fuel was isolated in a hot cell and shielding was introduced during later stages of sample preparation. The resulting sample contained numerous sample-preparation artifacts but allowed analysis of microstructures from selected areas.

  5. Controlled metal-semiconductor sintering/alloying by one-directional reverse illumination

    DOEpatents

    Sopori, Bhushan L.

    1993-01-01

    Metal strips deposited on a top surface of a semiconductor substrate are sintered at one temperature simultaneously with alloying a metal layer on the bottom surface at a second, higher temperature. This simultaneous sintering of metal strips and alloying a metal layer on opposite surfaces of the substrate at different temperatures is accomplished by directing infrared radiation through the top surface to the interface of the bottom surface with the metal layer where the radiation is absorbed to create a primary hot zone with a temperature high enough to melt and alloy the metal layer with the bottom surface of the substrate. Secondary heat effects, including heat conducted through the substrate from the primary hot zone and heat created by infrared radiation reflected from the metal layer to the metal strips, as well as heat created from some primary absorption by the metal strips, combine to create secondary hot zones at the interfaces of the metal strips with the top surface of the substrate. These secondary hot zones are not as hot as the primary hot zone, but they are hot enough to sinter the metal strips to the substrate.

  6. Exploring Equilibrium Chemistry for Hot Exoplanets

    NASA Astrophysics Data System (ADS)

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Challener, Ryan

    2015-11-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Young 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime of 0.1 to 1 bar. These results are compared to a variety of exoplanets (Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an updated thermodynamic library) is validated with the thermochemical model presented in Venot et al. (2012) for HD 209458b and HD 189733b. This same analysis has then been extended to the cooler planet HD 97658b. Spectra are generated from both models’ abundances using the open source code transit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  7. Exploring Chemical Equilibrium in Hot Jovians

    NASA Astrophysics Data System (ADS)

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Blecic, Jasmina; Challener, Ryan

    2016-01-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Yung 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime 0.1 to 1 bar. These results are compared to a variety of exoplanets(Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an up-dated thermodynamic library) is compared with the thermochemical model presented in Venotet al. (2012) for HD 209458b and HD 189733b. This same analysis is then applied to the cooler planet HD 97658b. Spectra are generated and we compare both models' outputs using the open source codetransit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. Thiswork was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  8. Theoretical predictions for hot-carrier generation from surface plasmon decay

    NASA Astrophysics Data System (ADS)

    Sundararaman, Ravishankar; Narang, Prineha; Jermyn, Adam S.; Goddard, William A., III; Atwater, Harry A.

    2014-12-01

    Decay of surface plasmons to hot carriers finds a wide variety of applications in energy conversion, photocatalysis and photodetection. However, a detailed theoretical description of plasmonic hot-carrier generation in real materials has remained incomplete. Here we report predictions for the prompt distributions of excited ‘hot’ electrons and holes generated by plasmon decay, before inelastic relaxation, using a quantized plasmon model with detailed electronic structure. We find that carrier energy distributions are sensitive to the electronic band structure of the metal: gold and copper produce holes hotter than electrons by 1-2 eV, while silver and aluminium distribute energies more equitably between electrons and holes. Momentum-direction distributions for hot carriers are anisotropic, dominated by the plasmon polarization for aluminium and by the crystal orientation for noble metals. We show that in thin metallic films intraband transitions can alter the carrier distributions, producing hotter electrons in gold, but interband transitions remain dominant.

  9. Theoretical predictions for hot-carrier generation from surface plasmon decay

    PubMed Central

    Sundararaman, Ravishankar; Narang, Prineha; Jermyn, Adam S.; Goddard III, William A.; Atwater, Harry A.

    2014-01-01

    Decay of surface plasmons to hot carriers finds a wide variety of applications in energy conversion, photocatalysis and photodetection. However, a detailed theoretical description of plasmonic hot-carrier generation in real materials has remained incomplete. Here we report predictions for the prompt distributions of excited ‘hot’ electrons and holes generated by plasmon decay, before inelastic relaxation, using a quantized plasmon model with detailed electronic structure. We find that carrier energy distributions are sensitive to the electronic band structure of the metal: gold and copper produce holes hotter than electrons by 1–2 eV, while silver and aluminium distribute energies more equitably between electrons and holes. Momentum-direction distributions for hot carriers are anisotropic, dominated by the plasmon polarization for aluminium and by the crystal orientation for noble metals. We show that in thin metallic films intraband transitions can alter the carrier distributions, producing hotter electrons in gold, but interband transitions remain dominant. PMID:25511713

  10. Archaeal Nitrification in Hot Springs

    NASA Astrophysics Data System (ADS)

    Richter, A.; Daims, H.; Reigstad, L.; Wanek, W.; Wagner, M.; Schleper, C.

    2006-12-01

    Biological nitrification, i.e. the aerobic conversion of ammonia to nitrate via nitrite, is a major component of the global nitrogen cycle. Until recently, it was thought that the ability to aerobically oxidize ammonia was confined to bacteria of the phylum Proteobacteria. However, it has recently been shown that Archaea of the phylum Crenarchaeota are also capable of ammonia oxidation. As many Crenarchaeota are thermophilic or hyperthermophilic, and at least some of them are capable of ammonia oxidation we speculated on the existence of (hyper)thermophilic ammonia-oxidizing archaea (AOA). Using PCR primers specifically targeting the archaeal ammonia monooxygenase (amoA) gene, we were indeed able to confirm the presence of such organisms in several hot springs in Reykjadalur, Iceland. These hot springs exhibited temperatures well above 80 °C and pH values ranging from 2.0 to 4.5. To proof that nitrification actually took place under these extreme conditions, we measured gross nitrification rates by the isotope pool dilution method; we added 15N-labelled nitrate to the mud and followed the dilution of the label by nitrate production from ammonium either in situ (incubation in the hot spring) or under controlled conditions in the laboratory (at 80 °C). The nitrification rates in the hot springs ranged from 0.79 to 2.22 mg nitrate-N per L of mud and day. Controls, in which microorganisms were killed before the incubations, demonstrated that the nitrification was of biological origin. Addition of ammonium increased the gross nitrification rate approximately 3-fold, indicating that the nitrification was ammonium limited under the conditions used. Collectively, our study provides evidence that (1) AOA are present in hot springs and (2) that they are actively nitrifying. These findings have major implications for our understanding of nitrogen cycling of hot environments.

  11. Hot electron pump: a plasmonic rectifying antenna (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Yanik, Ahmet A.; Hossain, Golam I.

    2015-09-01

    Plasmonic nanostructures have been widely explored to improve absorption efficiency of conventional solar cells, either by employing them as a light scatterer, or as a source of local field enhancement. Unavoidable ohmic loss associated with the plasmonic metal nanostructures in visible spectrum, limits the efficiency improvement of photovoltaic devices by employing this local photon density of states (LDOS) engineering approach. Instead of using plasmonic structures as efficiency improving layer, recently, there has been a growing interest in exploring plasmoinc nanoparticle as the active medium for photovoltaic device. By extracting hot electrons that are created in metallic nanoparticles in a non-radiative Landau decay of surface plasmons, many novel plasmonic photovoltaic devices have been proposed. Moreover, these hot electrons in metal nanoparticles promises high efficiency with a spectral response that is not limited by the band gap of the semiconductors (active material of conventional solar cell). In this work, we will show a novel photovoltaic configuration of plasmonic nanoparticle that acts as an antenna by capturing free space ultrahigh frequency electromagnetic wave and rectify them through an ultrafast hot electron pump and eventually inject DC current in the contact of the device. We will introduce a bottom-up quantum mechanical approach model to explain fundamental physical processes involved in this hot electron pump rectifying antenna and it's ultrafast dynamics. Our model is based on non-equilibrium Green's function formalism, a robust theoretical framework to investigate transport and design nanoscale electronic devices. We will demonstrate some fundamental limitations that go the very foundations of quantum mechanics.

  12. Hot isostatic pressing: Conference proceedings

    SciTech Connect

    Froes, F.H.; Hebeisen, J.; Widmer, R.

    1996-12-31

    The International Conference on Hot Isostatic Pressing was held on May 20-22, 1996, in Andover, Massachusetts. This conference discussed the state-of-the-art of hot isostatic pressing (HIP) and competing compaction techniques. HIP allows complex cost-effective near net shapes to be produced from powder products, densification of castings thereby enhancing performance, retention of metastable structures such as nano-sized grains, and even creative food processing. Sections in the conference covered such items as fundamentals, mathematical modeling, equipment and instrumentation, advanced materials and processes, composite materials, casting densification, surface treatments, HIP bonding, and competing technologies. Forty five papers were processed separately for inclusion on the data base.

  13. Hot Gas Halos in Galaxies

    SciTech Connect

    Mulchaey, John S.; Jeltema, Tesla E.

    2010-06-08

    We use Chandra and XMM-Newton to study how the hot gas content in early-type galaxies varies with environment. We find that the L{sub X}-L{sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. This suggests that internal processes such as supernovae driven winds or AGN feedback may expel hot gas from low mass field galaxies. Such mechanisms are less effective in groups and clusters where the presence of an intragroup or intracluster medium may confine outflowing material.

  14. Hot conditioning equipment conceptual design report

    SciTech Connect

    Bradshaw, F.W., Westinghouse Hanford

    1996-08-06

    This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage.

  15. Menopausal hot flashes: Randomness or rhythmicity

    NASA Astrophysics Data System (ADS)

    Kronenberg, Fredi

    1991-10-01

    Menopausal hot flashes are episodes of flushing, increased heart rate, skin blood flow and skin temperature, and a sensation of heat. The thermoregulatory and cardiovascular concomitants of hot flashes are associated with peaks in the levels of various hormones and neurotransmitters in the peripheral circulation. Although hot flashes affect about 75% of women, and are the primary reason that women at menopause seek medical attention, the mechanism of hot flashes is still not understood. Hot flashes vary in frequency and intensity both within and between individuals, and have been thought of as occurring randomly. Yet, some women report that their hot flashes are worse at a particular time of day or year. Initial examination of subjects' recordings of their hot flashes showed diurnal patterns of hot flash occurrence. There also seems to be a diurnal rhythm of hot flash intensity. Continuous physiological monitoring of hot flashes is facilitating the analysis of these patterns, which is revealing circadian and ultradian periodicities. The occurrence of hot flashes can be modulated by external and internal factors, including ambient temperature and fever. Rhythms of thermoregulatory and endocrine functions also may influence hot flash patterns. Examination of the interrelationships between the various systems of the body involved in hot flashes, and a multidisciplinary approach to the analysis of hot flash patterns, will aid our understanding of this complex phenomenon.

  16. Non-equilibrium hot carrier dynamics in plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Narang, Prineha; Sundararaman, Ravishankar; Jermyn, Adam; Cortes, Emiliano; Maier, Stefan A.; Goddard, William A., III

    Decay of surface plasmons to hot carriers is a new direction that has attracted considerable fundamental and application interest, yet a fundamental understanding of ultrafast plasmon decay processes and the underlying microscopic mechanisms remain incomplete. Ultrafast experiments provide insights into the relaxation of non-equilibrium carriers at the tens and hundreds of femtoseconds time scales, but do not yet directly probe shorter times with nanometer spatial resolution. Here we report the first ab initio calculations of non equilibrium transport of plasmonic hot carriers in metals and experimental observation of the injection of these carriers into molecules tethered to the metal surface. Specifically, metallic nanoantennas functionalized with a molecular monolayer allow for the direct probing of electron injection via surface enhanced Raman spectroscopy of the original and reduced molecular species. We combine first principles calculations of electron-electron and electron-phonon scattering rates with Boltzmann transport simulations to predict the ultrafast dynamics and transport of carriers in real materials. We also predict and compare the evolution of electron distributions in ultrafast experiments on noble metal nanoparticles.

  17. Planar microcavity-integrated hot-electron photodetector

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Wu, Kai; Zhan, Yaohui; Giannini, Vincenzo; Li, Xiaofeng

    2016-05-01

    Hot-electron photodetectors are attracting increasing interest due to their capability in below-bandgap photodetection without employing classic semiconductor junctions. Despite the high absorption in metallic nanostructures via plasmonic resonance, the fabrication of such devices is challenging and costly due to the use of high-dimensional sub-wavelength nanostructures. In this study, we propose a planar microcavity-integrated hot-electron photodetector (MC-HE PD), in which the TCO/semiconductor/metal (TCO: transparent conductive oxide) structure is sandwiched between two asymmetrically distributed Bragg reflectors (DBRs) and a lossless buffer layer. Finite-element simulations demonstrate that the resonant wavelength and the absorption efficiency of the device can be manipulated conveniently by tailoring the buffer layer thickness and the number of top DBR pairs. By benefitting from the largely increased electric field at the resonance frequency, the absorption in the metal can reach 92%, which is a 21-fold enhancement compared to the reference without a microcavity. Analytical probability-based electrical calculations further show that the unbiased responsivity can be up to 239 nA mW-1, which is more than an order of magnitude larger than that of the reference. Furthermore, the MC-HE PD not only exhibits a superior photoelectron conversion ability compared to the approach with corrugated metal, but also achieves the ability to tune the near infrared multiband by employing a thicker buffer layer.

  18. Hot-electron-based solar energy conversion with metal–semiconductor nanodiodes

    NASA Astrophysics Data System (ADS)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-01

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal–semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  19. Hot subdwarfs in globular clusters

    SciTech Connect

    Drukier, G.A.; Fahlman, G.G.; Richter, H.B. )

    1989-07-01

    Spectra of faint blue stars in the globular clusters M71 and M4 are presented. The spectra suggest that they are hot subdwarfs. Arguments in favor of membership in their respective clusters and comments regarding their evolutionary status are given. 18 refs.

  20. Origins of Hot Jupiters, Revisited

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Bodenheimer, Peter; Laughlin, Greg

    2016-05-01

    Hot Jupiters, giant extrasolar planets with orbital periods less than ~10 days, have long been thought to form at large radial distances (a > 2AU) in protoplanetary disks, only to subsequently experience large-scale inward migration to the small orbital radii at which they are observed. Here, we propose that a substantial fraction of the hot Jupiter population forms in situ, with the Galactically prevalent short-period super-Earths acting as the source population. Our calculations suggest that under conditions appropriate to the inner regions of protoplanetary disks, rapid gas accretion can be initiated for solid cores of 10-20 Earth masses, in line with the conventional picture of core-nucleated accretion. The planetary conglomeration process, coupled with subsequent gravitational contraction and spin down of the host star, drives sweeping secular resonances through the system, increasing the mutual inclinations of exterior, low-mass companions to hot Jupiters. Accordingly, this formation scenario leads to testable consequences, including the expectation that hot Jupiters should frequently be accompanied by additional non-transiting planets, reminiscent of those observed in large numbers by NASA’s Kepler Mission and Doppler velocity surveys. High-precision radial velocity monitoring provides the best prospect for their detection.

  1. Origins of Hot Jupiters, Revisited

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Bodenheimer, Peter; Laughlin, Greg

    2015-12-01

    Hot Jupiters, giant extrasolar planets with orbital periods less than ~10 days, have long been thought to form at large radial distances (a > 2AU) in protostellar disks, only to subsequently experience large-scale inward migration to the small orbital radii at which they are observed. Here, we propose that a substantial fraction of the hot Jupiter population forms in situ, with the Galactically prevalent short-period super-Earths acting as the source population. Our calculations suggest that under conditions appropriate to the inner regions of protostellar disks, rapid gas accretion can be initiated for solid cores of 10-20 Earth masses, in line with the conventional picture of core-nucleated accretion. This formation scenario leads to testable consequences, including the expectation that hot Jupiters should frequently be accompanied by additional planets, reminiscent of those observed in large numbers by NASA’s Kepler Mission and Doppler velocity surveys. However, dynamical interactions during the early stages of planetary systems' evolutionary lifetimes tend to increase the mutual inclinations of exterior, low-mass companions to hot Jupiters, making transits rare. High-precision radial velocity monitoring provides the best prospect for their detection.

  2. Solar Technician Program Blows Hot

    ERIC Educational Resources Information Center

    Ziegler, Peg Moran

    1977-01-01

    A training program for solar heating technicians was initiated at Sonoma State College's School of Environmental Studies for CETA applicants. Among the projects designed and built were a solar alternative energy center, a solar hot water system, and a solar greenhouse. (MF)

  3. Solar hot-water system

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Design data brochure describes domestic solar water system that uses direct-feed system designed to produce 80 gallons of 140 F hot water per day to meet needs of single family dwelling. Brochure also reviews annual movements of sun relative to earth and explains geographic considerations in collector orientation and sizing.

  4. Hot, Cold, and Really Cold.

    ERIC Educational Resources Information Center

    Leyden, Michael

    1997-01-01

    Describes a physics experiment investigating temperature prediction and the relationship between the physical properties of heat units, melting, dissolving, states of matter, and energy loss. Details the experimental setup, which requires hot and cold water, a thermometer, and ice. Notes that the experiment employs a deliberate counter-intuitive…

  5. Solar Hot Water Hourly Simulation

    2009-12-31

    The Software consists of a spreadsheet written in Microsoft Excel which provides an hourly simulation of a solar hot water heating system (including solar geometry, solar collector efficiency as a function of temperature, energy balance on storage tank and lifecycle cost analysis).

  6. Theoretical analysis of hot electron dynamics in nanorods

    PubMed Central

    Kumarasinghe, Chathurangi S.; Premaratne, Malin; Agrawal, Govind P.

    2015-01-01

    Localised surface plasmons create a non-equilibrium high-energy electron gas in nanostructures that can be injected into other media in energy harvesting applications. Here, we derive the rate of this localised-surface-plasmon mediated generation of hot electrons in nanorods and the rate of injecting them into other media by considering quantum mechanical motion of the electron gas. Specifically, we use the single-electron wave function of a particle in a cylindrical potential well and the electric field enhancement factor of an elongated ellipsoid to derive the energy distribution of electrons after plasmon excitation. We compare the performance of nanorods with equivolume nanoparticles of other shapes such as nanospheres and nanopallets and report that nanorods exhibit significantly better performance over a broad spectrum. We present a comprehensive theoretical analysis of how different parameters contribute to efficiency of hot-electron harvesting in nanorods and reveal that increasing the aspect ratio can increase the hot-electron generation and injection, but the volume shows an inverse dependency when efficiency per unit volume is considered. Further, the electron thermalisation time shows much less influence on the injection rate. Our derivations and results provide the much needed theoretical insight for optimization of hot-electron harvesting process in highly adaptable metallic nanorods. PMID:26202823

  7. Fundamental Limitations to Plasmonic Hot-Carrier Solar Cells.

    PubMed

    Zhang, Yu; Yam, ChiYung; Schatz, George C

    2016-05-19

    Detailed balance between photon-absorption and energy loss constrains the efficiency of conventional solar cells to the Shockley-Queisser limit. However, if solar illumination can be absorbed over a wide spectrum by plasmonic structures, and the generated hot-carriers can be collected before relaxation, the efficiency of solar cells may be greatly improved. In this work, we explore the opportunities and limitations for making plasmonic solar cells, here considering a design for hot-carrier solar cells in which a conventional semiconductor heterojunction is attached to a plasmonic medium such as arrays of gold nanoparticles. The underlying mechanisms and fundamental limitations of this cell are studied using a nonequilibrium Green's function method, and the numerical results indicate that this cell can significantly improve the absorption of solar radiation without reducing open-circuit voltage, as photons can be absorbed to produce mobile carriers in the semiconductor as long as they have energy larger than the Schottky barrier rather than above the bandgap. However, a significant fraction of the hot-carriers have energies below the Schottky barrier, which makes the cell suffer low internal quantum efficiency. Moreover, quantum efficiency is also limited by hot-carrier relaxation and metal-semiconductor coupling. The connection of these results to recent experiments is described, showing why plasmonic solar cells can have less than 1% efficiency. PMID:27136049

  8. Fundamental Limitations to Plasmonic Hot-Carrier Solar Cells.

    PubMed

    Zhang, Yu; Yam, ChiYung; Schatz, George C

    2016-05-19

    Detailed balance between photon-absorption and energy loss constrains the efficiency of conventional solar cells to the Shockley-Queisser limit. However, if solar illumination can be absorbed over a wide spectrum by plasmonic structures, and the generated hot-carriers can be collected before relaxation, the efficiency of solar cells may be greatly improved. In this work, we explore the opportunities and limitations for making plasmonic solar cells, here considering a design for hot-carrier solar cells in which a conventional semiconductor heterojunction is attached to a plasmonic medium such as arrays of gold nanoparticles. The underlying mechanisms and fundamental limitations of this cell are studied using a nonequilibrium Green's function method, and the numerical results indicate that this cell can significantly improve the absorption of solar radiation without reducing open-circuit voltage, as photons can be absorbed to produce mobile carriers in the semiconductor as long as they have energy larger than the Schottky barrier rather than above the bandgap. However, a significant fraction of the hot-carriers have energies below the Schottky barrier, which makes the cell suffer low internal quantum efficiency. Moreover, quantum efficiency is also limited by hot-carrier relaxation and metal-semiconductor coupling. The connection of these results to recent experiments is described, showing why plasmonic solar cells can have less than 1% efficiency.

  9. Processing map for hot working of powder

    NASA Astrophysics Data System (ADS)

    Radhakrishna Bhat, B. V.; Mahajan, Y. R.; Roshan, H. Md.; Prasad, Yvrk

    1992-08-01

    The constitutive flow behavior of a metal matrix composite (MMC) with 2124 aluminum containing 20 vol pct silicon carbide particulates under hot-working conditions in the temperature range of 300 °C to 550 °C and strain-rate range of 0.001 to 1 s-1 has been studied using hot compression testing. Processing maps depicting the variation of the efficiency of power dissipation given by [2m/(m + 1)] (where m is the strain-rate sensitivity of flow stress) with temperature and strain rate have been established for the MMC as well as for the matrix material. The maps have been interpreted on the basis of the Dynamic Materials Model (DMM). [3] The MMC exhibited a domain of superplasticity in the temperature range of 450 °C to 550 °C and at strain rates less than 0.1 s-1. At 500 °C and 1 s-1 strain rate, the MMC undergoes dynamic recrystallization (DRX), resulting in a reconstitution of microstructure. In comparison with the map for the matrix material, the DRX domain occurred at a strain rate higher by three orders of magnitude. At temperatures lower than 400 °C, the MMC exhibited dynamic recovery, while at 550 °C and 1 s-1, cracking occurred at the prior particle boundaries (representing surfaces of the initial powder particles). The optimum temperature and strain-rate combination for billet conditioning of the MMC is 500 °C and 1 s-1, while secondary metalworking may be done in the super- plasticity domain. The MMC undergoes microstructural instability at temperatures lower than 400 °C and strain rates higher than 0.1 s-1.

  10. Graphene vertical hot-electron terahertz detectors

    SciTech Connect

    Ryzhii, V.; Satou, A.; Otsuji, T.; Ryzhii, M.; Mitin, V.; Shur, M. S.

    2014-09-21

    We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A{sub 3}B{sub 5} materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

  11. The Detection of a Hot Molecular Core in the Large Magellanic Cloud with ALMA

    NASA Astrophysics Data System (ADS)

    Shimonishi, Takashi; Onaka, Takashi; Kawamura, Akiko; Aikawa, Yuri

    2016-08-01

    We report the first detection of a hot molecular core outside our Galaxy based on radio observations with ALMA toward a high-mass young stellar object (YSO) in a nearby low metallicity galaxy, the Large Magellanic Cloud (LMC). Molecular emission lines of CO, C17O, HCO+, H13CO+, H2CO, NO, SiO, H2CS, 33SO, 32SO2, 34SO2, and 33SO2 are detected from a compact region (˜0.1 pc) associated with a high-mass YSO, ST11. The temperature of molecular gas is estimated to be higher than 100 K based on rotation diagram analysis of SO2 and 34SO2 lines. The compact source size, warm gas temperature, high density, and rich molecular lines around a high-mass protostar suggest that ST11 is associated with a hot molecular core. We find that the molecular abundances of the LMC hot core are significantly different from those of Galactic hot cores. The abundances of CH3OH, H2CO, and HNCO are remarkably lower compared to Galactic hot cores by at least 1-3 orders of magnitude. We suggest that these abundances are characterized by the deficiency of molecules whose formation requires the hydrogenation of CO on grain surfaces. In contrast, NO shows a high abundance in ST11 despite the notably low abundance of nitrogen in the LMC. A multitude of SO2 and its isotopologue line detections in ST11 imply that SO2 can be a key molecular tracer of hot core chemistry in metal-poor environments. Furthermore, we find molecular outflows around the hot core, which is the second detection of an extragalactic protostellar outflow. In this paper, we discuss the physical and chemical characteristics of a hot molecular core in the low metallicity environment.

  12. Researchers Identify Genes Linked to Hot Flashes

    MedlinePlus

    ... fullstory_161579.html Researchers Identify Genes Linked to Hot Flashes Mutations found in women of all races, ... Some women may be genetically predisposed to suffer hot flashes before or during menopause, a new study ...

  13. [Hygienic aspects of the hot water supply].

    PubMed

    Dergacheva, T S

    1991-08-01

    Hygienic significance of hot water-supply was demonstrated. In the case of the sanitary inspection deficiency it may be the complaints appearance. Hygiene of hot water-supply seems as an independent scientific branch of hygiene. PMID:1937089

  14. Acord 1-26 hot, dry well, Roosevelt Hot Springs hot dry rock prospect, Utah

    SciTech Connect

    Shannon, S.S. Jr.; Pettitt, R.; Rowley, J.; Goff, F.; Mathews, M.; Jacobson, J.J.

    1983-08-01

    The Acord 1-26 well is a hot, dry well peripheral to the Roosevelt Hot Springs known geothermal resource area (KGRA) in southwestern Utah. The bottom-hole temperature in this 3854-m-deep well is 230/sup 0/C, and the thermal gradient is 54/sup 0/C/km. The basal 685 m, comprised of biotite monzonite and quartz schist and gneiss, is a likely hot, dry rock (HDR) prospect. The hole was drilled in a structural low within the Milford Valley graben and is separated from the Roosevelt KGRA to the east by the Opal Mound Fault and other basin faults. An interpretation of seismic data approximates the subsurface structure around the well using the lithology in the Acord 1-26 well. The hole was drilled with a minimum of difficulty, and casing was set to 2411 m. From drilling and geophysical logs, it is deduced that the subsurface blocks of crystalline rock in the vicinity of the Acord 1-26 well are tight, dry, shallow, impermeable, and very hot. A hydraulic fracture test of the crystalline rocks below 3170 m is recommended. Various downhole tools and techniques could be tested in promising HDR regimes within the Acord 1-26 well.

  15. OUT Success Stories: Solar Hot Water Technology

    DOE R&D Accomplishments Database

    Clyne, R.

    2000-08-01

    Solar hot water technology was made great strides in the past two decades. Every home, commercial building, and industrial facility requires hot water. DOE has helped to develop reliable and durable solar hot water systems. For industrial applications, the growth potential lies in large-scale systems, using flat-plate and trough-type collectors. Flat-plate collectors are commonly used in residential hot water systems and can be integrated into the architectural design of the building.

  16. Hydrologic indicators of hot spots and hot moments of mercury methylation along river corridors

    NASA Astrophysics Data System (ADS)

    Singer, Michael; Harrison, Lee; Donovan, Patrick; Blum, Joel; Marvin-DiPasquale, Mark

    2016-04-01

    The biogeochemical cycling of metals and other contaminants river-floodplain corridors is controlled by microbial activity is often affected by dynamic redox conditions. Riverine flooding thus has the potential to affect speciation of redox-sensitive metals such as mercury (Hg). Therefore, flow history over a period of decades potentially holds information on past production of bioavailable Hg. We investigate this process within a Northern California river system that has a legacy of industrial-scale 19th century hydraulic gold mining. In the first known application of this methodology, we combine hydraulic modeling, measurements of Hg species in sediment and biota, and first-order calculations to assess the role of river floodplains in producing monomethylmercury (MMHg), which accumulates in local and migratory biota. We identify areas that represent 'hot spots' (frequently inundated areas of floodplains) and 'hot moments' (floodplain areas inundated for consecutive long periods). We show that the probability of MMHg production in each sector of the river system is dependent on the spatial patterns of overbank flow and drainage, which affect its long-term redox history. MMHg bioaccumulation within the aquatic food web may pose a major risk to humans and waterfowl that eat migratory salmonids, which are being encouraged to come up these rivers to spawn, and there appears to be no end to MMHg production under a regime of increasingly common large floods with extended duration. These findings identify river floodplains as periodic, temporary, yet important, loci of biogeochemical transformation in which contaminants may undergo change during limited periods of the historical hydrologic record. We suggest that inundation is the primary driver of MMHg production in river corridors and that the entire flow history must be analyzed in terms of magnitude and frequency of inundation in order to accurately assess biogeochemical risks, rather than merely highlighting the

  17. COMPOSITIONAL DIVERSITY IN THE ATMOSPHERES OF HOT NEPTUNES, WITH APPLICATION TO GJ 436b

    SciTech Connect

    Moses, J. I.; Line, M. R.; Visscher, C.; Richardson, M. R.; Nettelmann, N.; Fortney, J. J.; Barman, T. S.; Stevenson, K. B.; Madhusudhan, N.

    2013-11-01

    Neptune-sized extrasolar planets that orbit relatively close to their host stars—often called {sup h}ot Neptunes{sup —}are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune, inefficient accretion of nebular gas is expected produce hot Neptunes whose masses are dominated by elements heavier than hydrogen and helium. At high atmospheric metallicities of 10-10,000 times solar, hot Neptunes will exhibit an interesting continuum of atmospheric compositions, ranging from more Neptune-like, H{sub 2}-dominated atmospheres to more Venus-like, CO{sub 2}-dominated atmospheres. We explore the predicted equilibrium and disequilibrium chemistry of generic hot Neptunes and find that the atmospheric composition varies strongly as a function of temperature and bulk atmospheric properties such as metallicity and the C/O ratio. Relatively exotic H{sub 2}O, CO, CO{sub 2}, and even O{sub 2}-dominated atmospheres are possible for hot Neptunes. We apply our models to the case of GJ 436b, where we find that a CO-rich, CH{sub 4}-poor atmosphere can be a natural consequence of a very high atmospheric metallicity. From comparisons of our results with Spitzer eclipse data for GJ 436b, we conclude that although the spectral fit from the high-metallicity forward models is not quite as good as the best fit obtained from pure retrieval methods, the atmospheric composition predicted by these forward models is more physically and chemically plausible in terms of the relative abundance of major constituents. High-metallicity atmospheres (orders of magnitude in excess of solar) should therefore be considered as a possibility for GJ 436b and other hot Neptunes.

  18. Compositional Diversity in the Atmospheres of Hot Neptunes, with Application to GJ 436b

    NASA Astrophysics Data System (ADS)

    Moses, J. I.; Line, M. R.; Visscher, C.; Richardson, M. R.; Nettelmann, N.; Fortney, J. J.; Barman, T. S.; Stevenson, K. B.; Madhusudhan, N.

    2013-11-01

    Neptune-sized extrasolar planets that orbit relatively close to their host stars—often called "hot Neptunes"—are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune, inefficient accretion of nebular gas is expected produce hot Neptunes whose masses are dominated by elements heavier than hydrogen and helium. At high atmospheric metallicities of 10-10,000 times solar, hot Neptunes will exhibit an interesting continuum of atmospheric compositions, ranging from more Neptune-like, H2-dominated atmospheres to more Venus-like, CO2-dominated atmospheres. We explore the predicted equilibrium and disequilibrium chemistry of generic hot Neptunes and find that the atmospheric composition varies strongly as a function of temperature and bulk atmospheric properties such as metallicity and the C/O ratio. Relatively exotic H2O, CO, CO2, and even O2-dominated atmospheres are possible for hot Neptunes. We apply our models to the case of GJ 436b, where we find that a CO-rich, CH4-poor atmosphere can be a natural consequence of a very high atmospheric metallicity. From comparisons of our results with Spitzer eclipse data for GJ 436b, we conclude that although the spectral fit from the high-metallicity forward models is not quite as good as the best fit obtained from pure retrieval methods, the atmospheric composition predicted by these forward models is more physically and chemically plausible in terms of the relative abundance of major constituents. High-metallicity atmospheres (orders of magnitude in excess of solar) should therefore be considered as a possibility for GJ 436b and other hot Neptunes.

  19. Development of advanced hot-gas desulfurization sorbents. Final report

    SciTech Connect

    Jothimurugesan, K.; Adeyiga, A.A.; Gangwal, S.K.

    1997-10-01

    The objective of this project was to develop hot-gas desulfurization sorbent formulations for relatively lower temperature application, with emphasis on the temperature range from 343--538 C. The candidate sorbents include highly dispersed mixed metal oxides of zinc, iron, copper, cobalt, nickel and molybdenum. The specific objective was to develop suitable sorbents, that would have high and stable surface area and are sufficiently reactive and regenerable at the relatively lower temperatures of interest in this work. Stability of surface area during regeneration was achieved by adding stabilizers. To prevent sulfation, catalyst additives that promote the light-off of the regeneration reaction at lower temperature was considered. Another objective of this study was to develop attrition-resistant advanced hot-gas desulfurization sorbents which show stable and high sulfidation reactivity at 343 to 538 C and regenerability at lower temperatures than leading first generation sorbents.

  20. Overview of Idaho National Laboratory's Hot Fuels Examination Facility

    SciTech Connect

    Adam B. Robinson; R. Paul Lind; Daniel M. Wachs

    2007-09-01

    The Hot Fuels Examination Facility (HFEF) at the Materials and Fuels Complex (MFC) of the Idaho National Laboratory was constructed in the 1960’s and opened for operation in the 1975 in support of the liquid metal fast breeder reactor research. Specifically the facility was designed to handle spent fuel and irradiated experiments from the Experimental Breeder Reactor EBRII, the Fast Flux Test Facility (FFTF), and the Transient Reactor Test Facility (TREAT). HFEF is a large alpha-gamma facility designed to remotely characterize highly radioactive materials. In the late 1980’s the facility also began support of the US DOE waste characterization including characterizing contact-handled transuranic (CH-TRU) waste. A description of the hot cell as well as some of its primary capabilities are discussed herein.

  1. Refrigerator with anti-sweat hot liquid loop

    SciTech Connect

    Woolley, S.J.; Cushing, D.S.; Jenkins, T.E.; Gerdes, K.W.; Sisler, R.R.

    1988-04-05

    A cabinet assembly for a refrigerator having a freezer compartment ontop with two top front corners, a fresh food compartment on the bottom, a mullion partition between the compartments and a hot liquid anti-sweat loop is described comprising; an outer sheet metal shell having a top panel, side panels and a front face, a brace located at each of the two top front corners of the cabinet and having two formed sections at right angles to each other and each section is formed as an inwardly open U-shaped channel having a base, a first leg and a second leg spaced apart and integrally joined to the base, fastening means for rigidly attaching each of the second leg of the corner braces to the flange of the third wall of the front face, and means to secure a portion of the hot liquid anti-sweat loop to the braces.

  2. Hot piston ring/cylinder liner materials - Selection and evaluation

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1988-01-01

    A materials testing program to determine whether automotive Stirling engine efficiency can be improved by locating 'hot piston rings' near the top of the pistons is described. Candidate materials were screened theoretically and experimentally by friction and wear tests. Based on the test results, a cobalt-based alloy, Stellite 6B, was chosen for the piston rings and PS200, which consists of a metal-bonded chromium carbide matrix with dispersed solid lubricants, was chosen as the cylinder coating. Tests of a modified engine and a baseline engine showed that the hot ring did reduce specific fuel consumption by up to 7 percent for some operating conditions and averaged about three percent for all conditions evaluated. Related applications of high-temperature coatings for shaft seals and as backup lubricants for gas bearings are also described.

  3. Spectropolarimetry of hot, luminous stars

    NASA Technical Reports Server (NTRS)

    Schulte-Ladbeck, Regina E.

    1994-01-01

    I review polarimetric observations of presumably single, hot luminous stars. The stellar types discussed are OB stars. B(e) supergiants, Luminous Blue Variables (LBV), Wolf-Rayet (W-R) stars, and type II supernovae (SN). It is shown that variable, intrinsic polarization is a common phenomenon in that part of the Hertzsprung-Russell (HR) diagram which these stars occupy. However, much observational work remains to be done before we can answer the most basic, statistical questions about the polarimetric properties of different groups of hot, luminous stars. Insight into the diagnostic power of polarization observations has been gained, but cannot be exploited without detailed models. Thus, while polarimetric observations do tell us that the mass-loss processes of all types of massive stars are time-dependent and anisotropic, the significance that this might have for the accuracy of their stellar parameters and evolutionary paths remains elusive.

  4. Hot atom chemistry and radiopharmaceuticals

    SciTech Connect

    Krohn, Kenneth A.; Moerlein, Stephen M.; Link, Jeanne M.; Welch, Michael J.

    2012-12-19

    The chemical products made in a cyclotron target are a combined result of the chemical effects of the nuclear transformation that made the radioactive atom and the bulk radiolysis in the target. This review uses some well-known examples to understand how hot atom chemistry explains the primary products from a nuclear reaction and then how radiation chemistry is exploited to set up the optimal product for radiosynthesis. It also addresses the chemical effects of nuclear decay. There are important principles that are common to hot atom chemistry and radiopharmaceutical chemistry. Both emphasize short-lived radionuclides and manipulation of high specific activity nuclides. Furthermore, they both rely on radiochromatographic separation for identification of no-carrieradded products.

  5. HOT HYDROGEN IN DIFFUSE CLOUDS

    SciTech Connect

    Cecchi-Pestellini, Cesare; Duley, Walt W.; Williams, David A. E-mail: wwduley@uwaterloo.ca

    2012-08-20

    Laboratory evidence suggests that recombination of adsorbed radicals may cause an abrupt temperature excursion of a dust grain to about 1000 K. One consequence of this is the rapid desorption of adsorbed H{sub 2} molecules with excitation temperatures of this magnitude. We compute the consequences of injection of hot H{sub 2} into cold diffuse interstellar gas at a rate of 1% of the canonical H{sub 2} formation rate. We find that the level populations of H{sub 2} in J = 3, 4, and 5 are close to observed values, and that the abundances of CH{sup +} and OH formed in reactions with hot hydrogen are close to the values obtained from observations of diffuse clouds.

  6. Noise Generation in Hot Jets

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Kenzakowski, Donald C.

    2007-01-01

    A prediction method based on the generalized acoustic analogy is presented, and used to evaluate aerodynamic noise radiated from high speed hot jets. The set of Euler equations are split into their respective non-radiating and residual components. Under certain conditions, the residual equations are rearranged to form a wave equation. This equation consists of a third-order wave operator, plus a number of nonlinear terms that are identified with the equivalent sources of sound and their statistical characteristics are modeled. A specialized RANS solver provides the base flow as well as turbulence quantities and temperature fluctuations that determine the source strength. The main objective here is to evaluate the relative contribution from various source elements to the far-field spectra and to show the significance of temperature fluctuations as a source of aerodynamic noise in hot jets.

  7. Hot gas engine heater head

    DOEpatents

    Berntell, John O.

    1983-01-01

    A heater head for a multi-cylinder double acting hot gas engine in which each cylinder is surrounded by an annular regenerator unit, and in which the tops of each cylinder and its surrounding regenerator are interconnected by a multiplicity of heater tubes. A manifold for the heater tubes has a centrally disposed duct connected to the top of the cylinder and surrounded by a wider duct connecting the other ends of the heater tubes with the regenerator unit.

  8. Hot atoms in cosmic chemistry.

    PubMed

    Rossler, K; Jung, H J; Nebeling, B

    1984-01-01

    High energy chemical reactions and atom molecule interactions might be important for cosmic chemistry with respect to the accelerated species in solar wind, cosmic rays, colliding gas and dust clouds and secondary knock-on particles in solids. "Hot" atoms with energies ranging from a few eV to some MeV can be generated via nuclear reactions and consequent recoil processes. The chemical fate of the radioactive atoms can be followed by radiochemical methods (radio GC or HPLC). Hot atom chemistry may serve for laboratory simulation of the reactions of energetic species with gaseous or solid interstellar matter. Due to the effective measurement of 10(8)-10(10) atoms only it covers a low to medium dose regime and may add to the studies of ion implantation which due to the optical methods applied are necessarily in the high dose regime. Experimental results are given for the systems: C/H2O (gas), C/H2O (solid, 77 K), N/CH4 (solid, 77K) and C/NH3 (solid, 77 K). Nuclear reactions used for the generation of 2 to 3 MeV atoms are: N(p,alpha) 11C, 16O(p,alpha pn) 11C and 12C(d,n) 13N with 8 to 45 MeV protons or deuterons from a cyclotron. Typical reactions products are: CO, CO2, CH4, CH2O, CH3OH, HCOOH, NH3, CH3NH2, cyanamide, formamidine, guanidine etc. Products of hot reactions in solids are more complex than in corresponding gaseous systems, which underlines the importance of solid state reactions for the build-up of precursors for biomolecules in space. As one of the major mechanisms for product formation, the simultaneous or fast consecutive reactions of a hot carbon with two target molecules (reaction complex) is discussed.

  9. Silicon Hot-Electron Bolometers

    NASA Technical Reports Server (NTRS)

    Stevenson, Thomas R.; Hsieh, Wen-Ting; Mitchell, Robert R.; Isenberg, Hal D.; Stahle, Carl M.; Cao, Nga T.; Schneider, Gideon; Travers, Douglas E.; Moseley, S. Harvey; Wollack, Edward J.

    2004-01-01

    We discuss a new type of direct detector, a silicon hot-electron bolometer, for measurements in the far-infrared and submillimeter spectral ranges. High performance bolometers can be made using the electron-phonon conductance in heavily doped silicon to provide thermal isolation from the cryogenic bath. Noise performance is expected to be near thermodynamic limits, allowing background limited performance for many far infrared and submillimeter photometric and spectroscopic applications.

  10. [Flushes, blushing or hot flushes].

    PubMed

    Merlen, J F; Coget, J M

    1987-01-01

    Apart from physiological flushes represented by emotional or prudish blushing, post-prandial flushes and menopausal hot flushes, various pathologic flushes exist of various etiologies: endocrine, dysmetabolic, histaminic and iatrogenic. Their pathogenicity is based mainly on local metabolites secretion provoking vasodilatation of the intermediary microcirculation rather than of the terminal microcirculation. Treatment is a function of etiology and therefore of the patient's history and results of clinical examination, functional exploration and standard biologic tests. PMID:3625050

  11. Pouring 'Cold Water' on Hot Accretion

    NASA Astrophysics Data System (ADS)

    Rubin, A. E.

    1995-09-01

    was concluded that the textures must have formed during cooling after hot accretion. However, because spinodal decomposition textures develop over the temperature range 1400-1100 K [14,15] and type-4 and -5 OC were probably not heated above 1000 K and 1050 K, respectively [16], these textures are probably relicts of chondrule formation. It was also suggested [14] that compositional zoning in pyroxenes indicates that type-3 OC cooled more rapidly than type-4 to -5 OC. However, OC metallographic cooling rates are not correlated with petrologic type [17]. Furthermore, experimental data [13] show that rare thick opx lamellae in H4 Conquista could not have formed during single stage cooling as expected in autometamorphism; a two-stage cooling history involving rapid cooling during chondrule formation followed by parent-body annealing is more plausible. Polycrystalline taenite. Polycrystalline taenite in H/L3 Tieschitz was interpreted as a relict solidification structure that failed to anneal into monocrystalline taenite because of rapid cooling (1700 to 1000 K within days to weeks) [18]; by analogy, it was proposed that all H3-6 chondrites containing polycrystalline taenite cooled rapidly from 1700 K [4], an idea inconsistent with prograde metamorphism. However, cooling rates in equilibrated chondrites that were slow enough to permit significant growth of kamacite would erase prior solidification zoning in taenite by solid-state diffusion [19,20]. This hypothesis, confirmed by computer modeling [21], invalidates the assumption that equilibrated OC containing polycrystalline taenite cooled rapidly. Polycrystalline taenite is most likely a pre-metamorphic relict. Heterogeneous metal grains. Compositionally and texturally heterogeneous metal grains in L6 Bruderheim are unlikely to have survived solid-state diffusion during prograde metamorphism [22]; these authors favored hot accretion followed by low-temperature annealing. However, Bruderheim is a fragmental breccia of shock

  12. Prediction of temperature distribution in the hot rolling of slabs

    NASA Astrophysics Data System (ADS)

    Serajzadeh, S.; Karimi Taheri, A.; Mucciardi, F.

    2002-03-01

    In the process of continuous hot slab rolling, it is vital to know the temperature distribution within the slab along the length of the rolling mill because temperature is the dominant parameter controlling the kinetics of metallurgical transformations and the flow stress of the rolled metal. In other words, the microstructural changes, the mechanical properties as well as the final dimensions of the product and roll-force depend on the temperature distribution within the metal being rolled. In this paper, a mathematical model based on the finite element method is utilized to predict the temperature distribution and microstructural changes during the continuous hot slab rolling process. The effects of various parameters such as the heat of deformation, the work-roll temperature, the rolling speed, and the heat transfer coefficient between the work-roll and the metal are all taken into account in the analyses. To verify the validity of the model and the generated computer code, a comparison is carried out between the theoretical and plant-recorded results.

  13. Production of glass or glass-ceramic to metal seals with the application of pressure

    DOEpatents

    Kelly, M.D.; Kramer, D.P.

    1985-01-04

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  14. Production of glass or glass-ceramic to metal seals with the application of pressure

    DOEpatents

    Kelly, Michael D.; Kramer, Daniel P.

    1987-11-10

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  15. WISE Discovers Hyperluminous Hot DOGs

    NASA Astrophysics Data System (ADS)

    Eisenhardt, Peter R.; Wu, J.; WISE Team

    2013-01-01

    One of the primary science objectives for NASA's Wide-field Infrared Survey Explorer (WISE) is to find the most luminous galaxies in the Universe. We have used WISE photometry to select an extraordinary all-sky sample of galaxies, which are prominent at 12 microns (W3) or 22 microns (W4), but faint or undetected at 3.4 microns (W1) and 4.6 microns (W2). Follow-up observations reveal that most of these galaxies are at redshift > 1.5, that they are hyperluminous (> 10^13 Lsun; with ~10% exceeding 10^14 Lsun, comparable to the most luminous optical QSOs). The follow-up observations also show that they are at least twice as hot as other types of infrared luminous galaxies, so that they are hot dust-obscured-galaxies, or Hot DOGs. Their SEDs have a very high mid-IR to submillimeter luminosity ratio, which is quite different from any existing galaxy templates. They may represent a rare, new phase in the galaxy evolution, possibly hosting extremely powerful super massive black holes.

  16. Hot Post-AGB Stars

    NASA Astrophysics Data System (ADS)

    Parthasarathy, M.; Gauba, G.; Fujii, T.; Nakada, Y.

    2001-08-01

    From the study of IRAS sources with far-IR colors similar to planetary nebulae (PNe), several proto-planetary nebulae with hot (OB) post-AGB central stars have been detected. These stars form an evolutionary link between the cooler G,F,A supergiant stars that have evolved off the Asymptotic Giant Branch (AGB) and the hot (OB) central stars of PNe. The optical spectra of these objects show strong Balmer emission lines and in some cases low excitation nebular emission lines such as [NII] and [SII] superposed on the OB stellar continuum. The absence of of [OIII] 5007Å line and the presence of low excitation nebular emission lines indicate that photoionisation has just started. The UV(IUE) spectra of some of these objects revealed violet shifted stellar wind P-Cygni profiles of CIV, SiIV and NV, indicating hot and fast stellar wind and post-AGB mass loss. These objects appear to be rapildy evolving into the early stages of PNe similar to that observed in the case of Hen1357 IRAS 17119-5926 (Stingray Nebula) and IRAS 18062+2410 SAO85766.

  17. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    1998-12-22

    Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

  18. Pore structure and reactivity changes in hot coal gas desulfurization sorbents

    SciTech Connect

    Sotirchos, S.V.

    1991-05-01

    The primary objective of the project was the investigation of the pore structure and reactivity changes occurring in metal/metal oxide sorbents used for desulfurization of hot coal gas during sulfidation and regeneration, with particular emphasis placed on the effects of these changes on the sorptive capacity and efficiency of the sorbents. Commercially available zinc oxide sorbents were used as model solids in our experimental investigation of the sulfidation and regeneration processes.

  19. A case of familial hot tub lung.

    PubMed

    Kitahara, Yoshihiro; Araki, Yusuke; Nakano, Kikuo

    2016-01-01

    Hot tub lung is a lung disease caused by Mycobacterium avium complex. We report the first case of familial hot tub lung appearing simultaneously in a husband and wife. Our case supports the consideration that hot tub lung is a hypersensitivity pneumonitis rather than an infectious lung disease. It also suggests that the state of hot tub lung changes seasonally depending on temperature variations, in a manner similar to summer-type hypersensitivity pneumonitis. This case demonstrates similarities between hot tub lung and summer-type hypersensitivity pneumonitis in regards to familial occurrence and seasonal changes in the disease state.

  20. Ultrafast Surface-Enhanced Raman Probing of the Role of Hot Electrons in Plasmon-Driven Chemistry.

    PubMed

    Brandt, Nathaniel C; Keller, Emily L; Frontiera, Renee R

    2016-08-18

    Hot electrons generated through plasmonic excitations in metal nanostructures show great promise for efficiently driving chemical reactions with light. However, the lifetime, yield, and mechanism of action of plasmon-generated hot electrons involved in a given photocatalytic process are not well understood. Here, we develop ultrafast surface-enhanced Raman scattering (SERS) as a direct probe of plasmon-molecule interactions in the plasmon-catalyzed dimerization of 4-nitrobenzenethiol to p,p'-dimercaptoazobenzene. Ultrafast SERS probing of these molecular reporters in plasmonic hot spots reveals transient Fano resonances, which we attribute to near-field coupling of Stokes-shifted photons to hot electron-driven metal photoluminescence. Surprisingly, we find that hot spots that yield more photoluminescence are much more likely to drive the reaction, which indirectly proves that plasmon-generated hot electrons induce the photochemistry. These ultrafast SERS results provide insight into the relative reactivity of different plasmonic hot spot environments and quantify the ultrafast lifetime of hot electrons involved in plasmon-driven chemistry. PMID:27488515

  1. Ultrafast Surface-Enhanced Raman Probing of the Role of Hot Electrons in Plasmon-Driven Chemistry.

    PubMed

    Brandt, Nathaniel C; Keller, Emily L; Frontiera, Renee R

    2016-08-18

    Hot electrons generated through plasmonic excitations in metal nanostructures show great promise for efficiently driving chemical reactions with light. However, the lifetime, yield, and mechanism of action of plasmon-generated hot electrons involved in a given photocatalytic process are not well understood. Here, we develop ultrafast surface-enhanced Raman scattering (SERS) as a direct probe of plasmon-molecule interactions in the plasmon-catalyzed dimerization of 4-nitrobenzenethiol to p,p'-dimercaptoazobenzene. Ultrafast SERS probing of these molecular reporters in plasmonic hot spots reveals transient Fano resonances, which we attribute to near-field coupling of Stokes-shifted photons to hot electron-driven metal photoluminescence. Surprisingly, we find that hot spots that yield more photoluminescence are much more likely to drive the reaction, which indirectly proves that plasmon-generated hot electrons induce the photochemistry. These ultrafast SERS results provide insight into the relative reactivity of different plasmonic hot spot environments and quantify the ultrafast lifetime of hot electrons involved in plasmon-driven chemistry.

  2. ESA uncovers Geminga's `hot spot'

    NASA Astrophysics Data System (ADS)

    2004-07-01

    16 July 2004 Astronomers using ESA’s X-ray observatory XMM-Newton have detected a small, bright ‘hot spot’ on the surface of the neutron star called Geminga, 500 light-years away. The hot spot is the size of a football field and is caused by the same mechanism producing Geminga’s X-ray tails. This discovery identifies the missing link between the X-ray and gamma-ray emission from Geminga. hi-res Size hi-res: 1284 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot This figure shows the effects of charged particles accelerated in the magnetosphere of Geminga. Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of particles kicked out by Geminga’s strong magnetic field, trail the neutron star as it moves about in space. Panel (b) shows how electrically charged particles interact with Geminga’s magnetic field. For example, if electrons (blue) are kicked out by the star, positrons (in red) hit the star’s magnetic poles like in an ‘own goal’. Panel (c) illustrates the size of Geminga’s magnetic field (blue) compared to that of the star itself at the centre (purple). The magnetic field is tilted with respect to Geminga’s rotation axis (red). Panel (d) shows the magnetic poles of Geminga, where charged particles hit the surface of the star, creating a two-million degrees hot spot, a region much hotter than the surroundings. As the star spins on its rotation axis, the hot spot comes into view and then disappears, causing the periodic colour change seen by XMM-Newton. An animated version of the entire sequence can be found at: Click here for animated GIF [low resolution, animated GIF, 5536 KB] Click here for AVI [high resolution, AVI with DIVX compression, 19128 KB] hi-res Size hi-res: 371 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (a) Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of

  3. Process window limiting hot spot monitoring for high-volume manufacturing

    NASA Astrophysics Data System (ADS)

    Jochemsen, Marinus; Anunciado, Roy; Timoshkov, Vadim; Hunsche, Stefan; Zhou, Xinjian; Jones, Chris; Callan, Neal

    2016-03-01

    As process window margins for cutting edge DUV lithography continue to shrink, the impact of systematic patterning defects on final yield increases. Finding process window limiting hot spot patterns and monitoring them in high volume manufacturing (HVM) is increasingly challenging with conventional methods, as the size of critical defects can be below the resolution of traditional HVM inspection tools. We utilize a previously presented computational method of finding hot spot patterns by full chip simulation and use this to guide high resolution review tools by predicting the state of the hot spots on all fields of production wafers. In experiments with a 10nm node Metal LELELE vehicle we show a 60% capture rate of after-etch defects down to 3nm in size, at specific hot spot locations. By using the lithographic focus and dose correction knobs we can reduce the number of patterning defects for this test case by ~60%.

  4. Plasmonic hot carrier dynamics in solid-state and chemical systems for energy conversion

    NASA Astrophysics Data System (ADS)

    Narang, Prineha; Sundararaman, Ravishankar; Atwater, Harry A.

    2016-06-01

    Surface plasmons provide a pathway to efficiently absorb and confine light in metallic nanostructures, thereby bridging photonics to the nano scale. The decay of surface plasmons generates energetic `hot' carriers, which can drive chemical reactions or be injected into semiconductors for nano-scale photochemical or photovoltaic energy conversion. Novel plasmonic hot carrier devices and architectures continue to be demonstrated, but the complexity of the underlying processes make a complete microscopic understanding of all the mechanisms and design considerations for such devices extremely challenging.Here,we review the theoretical and computational efforts to understand and model plasmonic hot carrier devices.We split the problem into three steps: hot carrier generation, transport and collection, and review theoretical approaches with the appropriate level of detail for each step along with their predictions.We identify the key advances necessary to complete the microscopic mechanistic picture and facilitate the design of the next generation of devices and materials for plasmonic energy conversion.

  5. Chandra grating spectroscopy of three hot white dwarfs

    NASA Astrophysics Data System (ADS)

    Adamczak, J.; Werner, K.; Rauch, T.; Schuh, S.; Drake, J. J.; Kruk, J. W.

    2012-10-01

    Context. High-resolution soft X-ray spectroscopic observations of single hot white dwarfs are scarce. With the Chandra Low-Energy Transmission Grating, we have observed two white dwarfs, one is of spectral type DA (LB 1919) and the other is a non-DA of spectral type PG 1159 (PG 1520+525). The spectra of both stars are analyzed, together with an archival Chandra spectrum of another DA white dwarf (GD 246). Aims: The soft X-ray spectra of the two DA white dwarfs are investigated in order to study the effect of gravitational settling and radiative levitation of metals in their photospheres. LB 1919 is of interest because it has a significantly lower metallicity than DAs with otherwise similar atmospheric parameters. GD 246 is the only white dwarf known that shows identifiable individual iron lines in the soft X-ray range. For the PG 1159 star, a precise effective temperature determination is performed in order to confine the position of the blue edge of the GW Vir instability region in the HRD. Methods: The Chandra spectra are analyzed with chemically homogeneous as well as stratified NLTE model atmospheres that assume equilibrium between gravitational settling and radiative acceleration of chemical elements. Archival EUV and UV spectra obtained with EUVE, FUSE, and HST are utilized to support the analysis. Results: No metals could be identified in LB 1919. All observations are compatible with a pure hydrogen atmosphere. This is in stark contrast to the vast majority of hot DA white dwarfs that exhibit light and heavy metals and to the stratified models that predict significant metal abundances in the atmosphere. For GD 246 we find that neither stratified nor homogeneous models can fit the Chandra spectrum. The Chandra spectrum of PG 1520+525 constrains the effective temperature to Teff = 150 000 ± 10 000 K. Therefore, this nonpulsating star together with the pulsating prototype of the GW Vir class (PG 1159 - 035) defines the location of the blue edge of the GW Vir

  6. Chandra Grating Spectroscopy of Three Hot White Dwarfs

    NASA Technical Reports Server (NTRS)

    Adamczak, J.; Werner, K.; Rauch, T.; Schuh, S.; Drake, J. J.; Kruk, J. W.

    2013-01-01

    High-resolution soft X-ray spectroscopic observations of single hot white dwarfs are scarce. With the Chandra Low-Energy Transmission Grating, we have observed two white dwarfs, one is of spectral type DA (LB1919) and the other is a non-DA of spectral type PG1159 (PG1520+525). The spectra of both stars are analyzed, together with an archival Chandra spectrum of another DA white dwarf (GD246). Aims. The soft X-ray spectra of the two DA white dwarfs are investigated in order to study the effect of gravitational settling and radiative levitation of metals in their photospheres. LB1919 is of interest because it has a significantly lower metallicity than DAs with otherwise similar atmospheric parameters. GD246 is the only white dwarf known that shows identifiable individual iron lines in the soft X-ray range. For the PG1159 star, a precise effective temperature determination is performed in order to confine the position of the blue edge of the GW Vir instability region in the HRD. Methods. The Chandra spectra are analyzed with chemically homogeneous as well as stratified NLTE model atmospheres that assume equilibrium between gravitational settling and radiative acceleration of chemical elements. Archival EUV and UV spectra obtained with EUVE, FUSE, and HST are utilized to support the analysis. Results. No metals could be identified in LB1919. All observations are compatible with a pure hydrogen atmosphere. This is in stark contrast to the vast majority of hot DA white dwarfs that exhibit light and heavy metals and to the stratified models that predict significant metal abundances in the atmosphere. For GD246 we find that neither stratified nor homogeneous models can fit the Chandra spectrum. The Chandra spectrum of PG1520+525 constrains the effective temperature to T(sub eff) = 150 000 +/- 10 000 K. Therefore, this nonpulsating star together with the pulsating prototype of the GWVir class (PG1159-035) defines the location of the blue edge of the GWVir instability region

  7. Application of induction coil measurements to the study of superalloy hot corrosion and oxidation

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.

    1984-01-01

    The assessment of the degree of hot corrosion attack on nickel based alloys is a difficult task, especially when the definition specifies that it must be in terms of metal consumed and even more difficult if the measurement must be nondestructive. The inductance of a solenoid coil responds to changes in volume of fill and composition of metal cores, therefore, it may be used for nondestructive measurement of hot corrosion. The hot corrosion of U700 was studied at 900 C in a Mach 0.3 flame doped with 0.85 wppm of sodium. The change of inductance was found to define the known corrosion behavior and to suggest its use as a tool with predictive capabilities. Sufficient sensitivity exists to detect oxidation of this alloy at 900 C.

  8. Tandem-structured, hot electron based photovoltaic cell with double Schottky barriers

    PubMed Central

    Lee, Young Keun; Lee, Hyosun; Park, Jeong Young

    2014-01-01

    We demonstrate a tandem-structured, hot electron based photovoltaic cell with double Schottky barriers. The tandem-structured, hot electron based photovoltaic cell is composed of two metal/semiconductor interfaces. Two types of tandem cells were fabricated using TiO2/Au/Si and TiO2/Au/TiO2, and photocurrent enhancement was detected. The double Schottky barriers lead to an additional pathway for harvesting hot electrons, which is enhanced through multiple reflections between the two barriers with different energy ranges. In addition, light absorption is improved by the band-to-band excitation of both semiconductors with different band gaps. Short-circuit current and energy conversion efficiency of the tandem-structured TiO2/Au/Si increased by 86% and 70%, respectively, compared with Au/Si metal/semiconductor nanodiodes, showing an overall solar energy conversion efficiency of 5.3%. PMID:24694838

  9. Coaxial Ag/ZnO/Ag nanowire for highly sensitive hot-electron photodetection

    SciTech Connect

    Zhan, Yaohui; Li, Xiaofeng Wu, Kai; Wu, Shaolong; Deng, Jiajia

    2015-02-23

    Single-nanowire photodetectors (SNPDs) are mostly propelled by p-n junctions, where the detection wavelength is constrained by the band-gap width. Here, we present a simple doping-free metal/semiconductor/metal SNPD, which shows strong detection tunability without such a material constraint. The proposed hot-electron SNPD exhibits superior optical and electrical advantages, i.e., optically the coaxial design leads to a strong asymmetrical photoabsorption and results in a high unidirectional photocurrent, as desired by the hot-electron collection; electrically the hot-electrons are generated in the region very close to the barrier, facilitating the electrical transport. Rigorous calculations predict an unbiased photoresponsivity of ∼200 nA/mW.

  10. Metal aminoboranes

    DOEpatents

    Burrell, Anthony K.; Davis, Benjamin J.; Thorn, David L.; Gordon, John C.; Baker, R. Thomas; Semelsberger, Troy Allen; Tumas, William; Diyabalanage, Himashinie Vichalya Kaviraj; Shrestha, Roshan P.

    2010-05-11

    Metal aminoboranes of the formula M(NH.sub.2BH.sub.3).sub.n have been synthesized. Metal aminoboranes are hydrogen storage materials. Metal aminoboranes are also precursors for synthesizing other metal aminoboranes. Metal aminoboranes can be dehydrogenated to form hydrogen and a reaction product. The reaction product can react with hydrogen to form a hydrogen storage material. Metal aminoboranes can be included in a kit.

  11. Aural stealth of portable HOT infrared imager

    NASA Astrophysics Data System (ADS)

    Veprik, Alexander

    2013-06-01

    Further reduction of size, weight and power consumption of the High Operating Temperature (HOT) infrared (IR) Integrated Detector-Dewar-Cooler Assemblies (IDDCA) eventually calls for development of high-speed cryocoolers. In case of integral rotary design, the immediate penalty is the more intensive slapping of compression and expansion pistons along with intensification of micro collisions inherent for the operation of crank-slide linkages featuring ball bearings. Resulting from this is the generation of impulsive vibration export, the spectrum of which features the driving frequency along with numerous multiples covering the entire range of audible frequencies. In a typical design of an infrared imager, the metal light-weight enclosure accommodates a directly mounted IDDCA and an optical train, thus serving as an optical bench and heat sink. This usually results in excitation of structural resonances in the said enclosure and, therefore, in excessive noise generation compromising the aural stealth. The author presents the complex approach to a design of aural undetectable infrared imagers in which the IDDCA is mounted upon the imager enclosure through a silent pad. Special attention is paid to resolving the line of sight stability and heat sinking issues. The demonstration imager relying on Ricor K562S based IDDCA meets the most stringent requirement to 10 meters aural non-detectability distance (per MIL-STD 1474D, Level II) even during boost cooldown phase of operation.

  12. Hot Isostatic Pressing (HIP): Techniques, applications and economical use

    NASA Astrophysics Data System (ADS)

    Bousack, H.

    1985-01-01

    Hot isostatic pressing (HIP) is used to regenerate defect components exposed to dynamic and permanent static loads causing pore formation. It consists in compacting and bonding of powders and solids by encapsulation. The HIP-equipment consists of a high pressure vessel, an oven and a rare gas system for production of isostatic pressure. The compacting procedure using diffusion and deformation processes depends on the pressing temperature. It is used in the production of hard metals, superalloys, fiber composites and ceramic components. It saves energy material and costs.

  13. Solar heating and hot water system installed at Listerhill, Alabama

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Solar system was installed into a new building and was designed to provide 79% of the estimated annual space heating load and 59% of the estimated annual potable hot water requirement. The collectors are flat plate, liquid manufactured by Reynolds Metals Company and cover a total area of 2344 square feet. The storage medium is water inhibited with NALCO 2755 and the container is an underground, unpressurized steel tank with a capacity of 5000 gallons. This report describes in considerable detail the solar heating facility and contains detailed drawings of the completed system.

  14. Method for making hot-pressed fiber-reinforced carbide-graphite composite

    DOEpatents

    Riley, Robert E.; Wallace Sr., Terry C.

    1979-01-01

    A method for the chemical vapor deposition of a uniform coating of tantalum metal on fibers of a woven graphite cloth is described. Several layers of the coated cloth are hot pressed to produce a tantalum carbide-graphite composite having a uniformly dispersed, fine grained tantalum carbide in graphite with compositions in the range of 15 to 40 volume percent tantalum carbide.

  15. The effect of hot salt on the mechanical properties of several superalloys

    NASA Technical Reports Server (NTRS)

    Nelson, E. E.

    1972-01-01

    The effect of sodium chloride on unstressed, transverse, tensile, metal specimens at elevated temperatures was determined. Results indicate that the mechanical properties of Inconel 718, Rene 41, titanium base alloy 13V-11Cr-3Al, Hastelloy X, HS25 (L605), HS188, and TDNiCr suffer degradation in tensile strength and ductility due to hot salt exposure.

  16. Method of measuring metal coating adhesion

    DOEpatents

    Roper, John R.

    1985-01-01

    A method for measuring metal coating adhesion to a substrate material comprising the steps of preparing a test coupon of substrate material having the metal coating applied to one surface thereof, applying a second metal coating of gold or silver to opposite surfaces of the test coupon by hot hollow cathode process, applying a coating to one end of each of two pulling rod members, joining the coated ends of the pulling rod members to said opposite coated surfaces of the test coupon by a solid state bonding technique and finally applying instrumented static tensile loading to the pulling rod members until fracture of the metal coating adhesion to the substrate material occurs.

  17. Luminescence from electroformed metal-isolator-metal-structures

    NASA Astrophysics Data System (ADS)

    Bischoff, Manfred

    The electroluminescence from metal-isolator-metal diodes is measured with a photon counter. From the time dependance of the electron temperature and density it appears that the electrons are not heated in the conduction band of the separating isolator or in vaccuum between the electrodes but in a highly degenerated semiconductor. The experimental results show that the grid temperature of the semiconductor filament material in case of a voltage pulse adds up to 1,500 K. The temperature of the hot electrons drops from 3,000 to 2,000 K. The charge carrier density and the recombination rate also increase.

  18. Insights into good hot oiling practices

    SciTech Connect

    Mansure, A.J. ); Barker, K.M. )

    1992-01-01

    One of the common oil-field wellbore problems is paraffin deposition. Even though hot oiling is usually the first method tried for removing paraffin, few operators appreciate the limitations of hot oiling and the potential for hot oiling to aggravate well problems and cause formation damage. Several hot oiling jobs were monitored to understand old pumpers tales'' and the dynamics of hot oiling. The field work was supported with laboratory analyses of the oil and calculations of thermal effectiveness. This limited study has shown that the chemical and thermal processes that occur during hot oiling are very complex and that there are significant variations in practices among operators. Key findings of this work include: (1) During a typical hot oiling job, a significant amount of the oil injected into the annulus goes into the formation, and hence, has the potential to damage the formation. (2) Organic particulates in stock tank oil may not completely dissolve/met as the oil passes through the hot-oiling-truck heat exchanger, hence, these particulates may plug the formation. (3) Hot oiling can vaporize oil in the tubing faster than the pump lifts oil. This interrupts paraffin removal from the well, and thus, since the wax is not removed from the well the wax is refined into harder deposits, can go deeper into the well, and can stick rods. These insights have been used to determine good hot oiling practices designed to maximize wax removal and minimize formation damage.

  19. Assessment of hot gas contaminant control

    SciTech Connect

    Rutkowski, M.D.; Klett, M.G.; Zaharchuk, R.

    1996-12-31

    The objective of this work is to gather data and information to assist DOE in responding to the NRC recommendation on hot gas cleanup by performing a comprehensive assessment of hot gas cleanup systems for advanced coal-based Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) including the status of development of the components of the hot gas cleanup systems, and the probable cost and performance impacts. The scope and time frame of information gathering is generally responsive to the boundaries set by the National Research council (NRC), but includes a broad range of interests and programs which cover hot gas cleanup through the year 2010. As the status of hot gas cleanup is continually changing, additional current data and information are being obtained for this effort from this 1996 METC Contractors` Review Meeting as well as from the 1996 Pittsburgh Coal Conference, and the University of Karlsruhe Symposium. The technical approach to completing this work consists of: (1) Determination of the status of hot gas cleanup technologies-- particulate collection systems, hot gas desulfurization systems, and trace contaminant removal systems; (2) Determination of hot gas cleanup systems cost and performance sensitivities. Analysis of conceptual IGCC and PFBC plant designs with hot gas cleanup have been performed. The impact of variations in hot gas cleanup technologies on cost and performance was evaluated using parametric analysis of the baseline plant designs and performance sensitivity.

  20. Partial oxidation process for producing a stream of hot purified gas

    DOEpatents

    Leininger, Thomas F.; Robin, Allen M.; Wolfenbarger, James K.; Suggitt, Robert M.

    1995-01-01

    A partial oxidation process for the production of a stream of hot clean gas substantially free from particulate matter, ammonia, alkali metal compounds, halides and sulfur-containing gas for use as synthesis gas, reducing gas, or fuel gas. A hydrocarbonaceous fuel comprising a solid carbonaceous fuel with or without liquid hydrocarbonaceous fuel or gaseous hydrocarbon fuel, wherein said hydrocarbonaceous fuel contains halides, alkali metal compounds, sulfur, nitrogen and inorganic ash containing components, is reacted in a gasifier by partial oxidation to produce a hot raw gas stream comprising H.sub.2, CO, CO.sub.2, H.sub.2 O, CH.sub.4, NH.sub.3, HCl, HF, H.sub.2 S, COS, N.sub.2, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream from the gasifier is split into two streams which are separately deslagged, cleaned and recombined. Ammonia in the gas mixture is catalytically disproportionated into N.sub.2 and H.sub.2. The ammonia-free gas stream is then cooled and halides in the gas stream are reacted with a supplementary alkali metal compound to remove HCl and HF. Alkali metal halides, vaporized alkali metal compounds and residual fine particulate matter are removed from the gas stream by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a regenerable sulfur-reactive mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 1000.degree. F.

  1. Partial oxidation process for producing a stream of hot purified gas

    DOEpatents

    Leininger, T.F.; Robin, A.M.; Wolfenbarger, J.K.; Suggitt, R.M.

    1995-03-28

    A partial oxidation process is described for the production of a stream of hot clean gas substantially free from particulate matter, ammonia, alkali metal compounds, halides and sulfur-containing gas for use as synthesis gas, reducing gas, or fuel gas. A hydrocarbonaceous fuel comprising a solid carbonaceous fuel with or without liquid hydrocarbonaceous fuel or gaseous hydrocarbon fuel, wherein said hydrocarbonaceous fuel contains halides, alkali metal compounds, sulfur, nitrogen and inorganic ash containing components, is reacted in a gasifier by partial oxidation to produce a hot raw gas stream comprising H{sub 2}, CO, CO{sub 2}, H{sub 2}O, CH{sub 4}, NH{sub 3}, HCl, HF, H{sub 2}S, COS, N{sub 2}, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream from the gasifier is split into two streams which are separately deslagged, cleaned and recombined. Ammonia in the gas mixture is catalytically disproportionated into N{sub 2} and H{sub 2}. The ammonia-free gas stream is then cooled and halides in the gas stream are reacted with a supplementary alkali metal compound to remove HCl and HF. Alkali metal halides, vaporized alkali metal compounds and residual fine particulate matter are removed from the gas stream by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a regenerable sulfur-reactive mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 1000 F. 1 figure.

  2. Study on load relaxation based on hot bending and sizing of Ti6Al4V alloy sheet

    NASA Astrophysics Data System (ADS)

    Po, Liu; Yingying, Zong; Debin, Shan; Bin, Guo

    2013-05-01

    The mechanism of hot sizing following sheet thermal forming of titanium alloy is considered as stress relaxation based on creep flow. A certain amount of internal stress in sheet metal parts can be relaxed during hot-sizing stage and hence the springback can be markedly reduced. Hot v-bending of Ti6Al4V sheet were carried out to study the behavior of load relaxation and springback in specimens after hot sizing, also known as shape retention. Experimental results reveal that load relaxation occurs during hot sizing following sheet v-bending. Reduction of springback angle obtained using hot sizing is obviously larger than that obtained without hot sizing under the same thermal environment. During hot sizing, springback angle decreases with increase in temperature and time, respectively. Load relaxation behavior is affected by loading method, namely constant velocity and two step loading. The linear relation between creep rate and load relaxation rate was deduced in hot-sizing stage. The calculated ratio shows good agreement with experimental data obtained by two-step loading. V-bending and sizing together with appropriate loading method are demonstrated as a good approach for stress relaxation analysis.

  3. PROCESS FOR PREPARING URANIUM METAL

    DOEpatents

    Prescott, C.H. Jr.; Reynolds, F.L.

    1959-01-13

    A process is presented for producing oxygen-free uranium metal comprising contacting iodine vapor with crude uranium in a reaction zone maintained at 400 to 800 C to produce a vaporous mixture of UI/sub 4/ and iodine. Also disposed within the maction zone is a tungsten filament which is heated to about 1600 C. The UI/sub 4/, upon contacting the hot filament, is decomposed to molten uranium substantially free of oxygen.

  4. A Strong Hot Spot Theorem

    SciTech Connect

    Bailey, David H.; Misiurewicz, Michal

    2005-12-31

    A real number alpha is said to be b-normal if every m-long string of digits appears in the base-b expansion of alpha with limiting frequency b-m. We prove that alpha is b-normal if and only if it possesses no base-b ''hot spot''. In other words, alpha is b-normal if and only if there is no real number y such that smaller and smaller neighborhoods of y are visited by the successive shifts of the base-b expansion of alpha with larger and larger frequencies, relative to the lengths of these neighborhoods

  5. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    Matthew R. June; John L. Hurley; Mark W. Johnson

    1999-04-01

    Iron aluminide hot gas filters have been developed using powder metallurgy techniques to form seamless cylinders. Three alloys were short-term corrosion tested in simulated IGCC atmospheres with temperatures between 925 F and 1200 F with hydrogen sulfide concentrations ranging from 783 ppm{sub v} to 78,300 ppm{sub v}. Long-term testing was conducted for 1500 hours at 925 F with 78,300 ppm{sub v}. The FAS and FAL alloys were found to be corrosion resistant in the simulated environments. The FAS alloy has been commercialized.

  6. Hot oxygen corona of Mars

    SciTech Connect

    Ip, W.H.

    1988-10-01

    Electron dissociative recombination of O2(+) ions in the Venus ionosphere, which may be an important source of suprathermal atomic oxygen, is presently considered as a factor in the Mars exosphere; due to the weaker surface gravitational attraction of Mars, a hot oxygen corona thus formed would be denser than that of Venus at altitudes greater than 2000 km despite Mars' lower ionospheric content. If such an extended oxygen corona does exist on Mars, its collisional interaction with Phobos would lead to the formation of an oxygen gas torus whose average number density is of the order of only 1-2/cu cm along the Phobos orbit. 51 references.

  7. Hot Flow Anomalies at Venus

    NASA Technical Reports Server (NTRS)

    Collinson, G. A.; Sibeck, David Gary; Boardsen, Scott A.; Moore, Tom; Barabash, S.; Masters, A.; Shane, N.; Slavin, J.A.; Coates, A.J.; Zhang, T. L.; Sarantos, M.

    2012-01-01

    We present a multi-instrument study of a hot flow anomaly (HFA) observed by the Venus Express spacecraft in the Venusian foreshock, on 22 March 2008, incorporating both Venus Express Magnetometer and Analyzer of Space Plasmas and Energetic Atoms (ASPERA) plasma observations. Centered on an interplanetary magnetic field discontinuity with inward convective motional electric fields on both sides, with a decreased core field strength, ion observations consistent with a flow deflection, and bounded by compressive heated edges, the properties of this event are consistent with those of HFAs observed at other planets within the solar system.

  8. Laboratory procedures used in the hot corrosion project

    SciTech Connect

    Jeys, T.R.

    1980-04-08

    The objective of the Hot Corrosion Project in the LLNL Metals and Ceramics Division is to study the physical and chemical mechanisms of corrosion of nickel, iron, and some of their alloys when these metals are subjected to oxidizing or sulfidizing environments at temperatures between 850 and 950/sup 0/C. To obtain meaningful data in this study, we must rigidly control many parameters. Parameters are discussed and the methods chosen to control them in this laboratory. Some of the mechanics and manipulative procedures that are specifically related to data access and repeatability are covered. The method of recording and processing the data from each experiment using an LS-11 minicomputer are described. The analytical procedures used to evaluate the specimens after the corrosion tests are enumerated and discussed.

  9. Hot electron spin transport in C60 fullerene

    NASA Astrophysics Data System (ADS)

    Hueso, Luis Eduardo; Gobbi, Marco; Bedoya-Pinto, Amilcar; Golmar, Federico; Llopis, Roger; Casanova, Felix

    2012-02-01

    Carbon-based molecular materials are interesting for spin transport application mainly due to their small sources of spin relaxation [1]. However, spin coherence lengths reported in many molecular films do not exceed a few tens of nanometers [2]. In this work we will present results showing how hot spin-polarized electrons injected well above the Fermi level in C60 fullerene films travel coherently for hundreds of nanometers. We fabricated hot-electron vertical transistors, in which the current created across an Al/Al2O3 junction is polarized by a metallic Co/Cu/Py spin valve trilayer and subsequently injected in the molecular thin film. This geometry allows us to determine the energy level alignment at each interface between different materials. Moreover, the collector magnetocurrent excess 85%, even for C60 films thicknesses of 300 nm. We believe these results show the importance of hot spin-polarized electron injection and propagation in molecular materials. [1] V. Dediu, L.E. Hueso, I. Bergenti, C. Taliani, Nature Mater. 8, 707 (2009) [2] M. Gobbi, F. Golmar, R. Llopis, F. Casanova, L.E. Hueso, Adv. Mater. 23, 1609 (2011)

  10. Hot piston ring/cylinder liner materials: Selection and evaluation

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1988-01-01

    In current designs of the automotive (kinematic) Stirling engine, the piston rings are made of a reinforced polymer and are located below the pistons because they cannot withstand the high temperatures in the upper cylinder area. Theoretically, efficiency could be improved if hot piston rings were located near the top of the pistons. Described is a program to select piston ring and cylinder coating materials to test this theory. Candidate materials were screened, then subjected to a pin or disk friction and wear test machine. Tests were performed in hydrogen at specimen temperatures up to 760 C to simulate environmental conditions in the region of the hot piston ring reversal. Based on the results of these tests, a cobalt based alloy, Stellite 6B, was chosen for the piston rings and PS200, which consists of a metal-bonded chromium carbide matrix with dispersed solid lubricants, was chosen as the cylinder coating. Tests of a modified engine and a baseline engine showed that the hot ring reduced specific fuel consumption by up to 7 percent for some operating conditions and averaged about 3 percent for all conditions evaluated. Related applications of high-temperature coatings for shaft seals and as back-up lubricants are also described.

  11. BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    Unknown

    2000-09-01

    The U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2}TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents. Overall chemical reactions with Zn{sub 2}TiO{sub 4} during the desulfurization (sulfidation)-regeneration cycle are shown. The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO{sub 2}.

  12. BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    Unknown

    1999-07-01

    The U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2}TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents. Overall chemical reactions with Zn{sub 2}TiO{sub 4} during the desulfurization (sulfidation)-regeneration cycle are shown. The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO{sub 2}.

  13. Modeling of planetesimal compaction by hot pressing

    NASA Astrophysics Data System (ADS)

    Neumann, W.; Breuer, D.; Spohn, T.

    2014-07-01

    Compaction of initially porous material prior to melting is an important process that has influenced the interior structure and the thermal evolution of planetesimals in their early history. On one hand, compaction decreases the porosity resulting in a reduction of the radius. On the other hand, the loss of porosity results in an increase of the thermal conductivity of the material and, thus, in a more efficient cooling. Porosity loss by hot pressing is the most efficient process of compaction in planetesimals and can be described by creep flow, which depends on temperature and stress. Hot pressing has been repeatedly modeled using a simplified approach, for which the porosity is gradually reduced in some fixed temperature interval between ~650 K and 700 K [see e.g. 1--3]. This approach neglects the dependence of compaction on stress. In the present study [see 4], we compare this ''parametrized'' method with a self-consistent calculation of porosity loss via a ''creep-related'' approach. We use our thermal evolution model from previous studies [5] to model compaction of an initially porous ordinary chondritic body and consider four basic packings of spherical dust grains (simple cubic, orthorhombic, rhombohedral, and body-centered cubic). Depending on the grain packing, we calculate the effective stress and the associated porosity change via the thermally activated creep flow. For comparison, compaction is also modeled by simply reducing the initial porosity linearly to zero between 650 and 700 K. Since we are interested in thermal metamorphism and not melting, we only consider bodies that experience a maximum temperature below the solidus temperature of the metal phase. For the creep related approach, the temperature interval in which compaction takes place depends strongly on the size of the planetesimal and is not fixed as assumed in the parametrized approach. Depending on the radius, the initial grain size, the activation energy, the initial porosity, and the

  14. Stellar wind models of subluminous hot stars

    NASA Astrophysics Data System (ADS)

    Krtička, J.; Kubát, J.; Krtičková, I.

    2016-09-01

    Context. Mass-loss rate is one of the most important stellar parameters. Mass loss via stellar winds may influence stellar evolution and modifies stellar spectrum. Stellar winds of subluminous hot stars, especially subdwarfs, have not been studied thoroughly. Aims: We aim to provide mass-loss rates as a function of subdwarf parameters and to apply the formula for individual subdwarfs, to predict the wind terminal velocities, to estimate the influence of the magnetic field and X-ray ionization on the stellar wind, and to study the interaction of subdwarf wind with mass loss from Be and cool companions. Methods: We used our kinetic equilibrium (NLTE) wind models with the radiative force determined from the radiative transfer equation in the comoving frame (CMF) to predict the wind structure of subluminous hot stars. Our models solve stationary hydrodynamical equations, that is the equation of continuity, equation of motion, and energy equation and predict basic wind parameters. Results: We predicted the wind mass-loss rate as a function of stellar parameters, namely the stellar luminosity, effective temperature, and metallicity. The derived wind parameters (mass-loss rates and terminal velocities) agree with the values derived from the observations. The radiative force is not able to accelerate the homogeneous wind for stars with low effective temperatures and high surface gravities. We discussed the properties of winds of individual subdwarfs. The X-ray irradiation may inhibit the flow in binaries with compact components. In binaries with Be components, the winds interact with the disk of the Be star. Conclusions: Stellar winds exist in subluminous stars with low gravities or high effective temperatures. Despite their low mass-loss rates, they are detectable in the ultraviolet spectrum and cause X-ray emission. Subdwarf stars may lose a significant part of their mass during the evolution. The angular momentum loss in magnetic subdwarfs with wind may explain their

  15. Texture evolution and mechanical anisotropy of biomedical hot-rolled Co-Cr-Mo alloy.

    PubMed

    Mori, Manami; Yamanaka, Kenta; Sato, Shigeo; Chiba, Akihiko

    2015-11-01

    Crystallographic textures and their effect on the mechanical anisotropy of a hot-rolled biomedical Co-Cr-Mo alloy were investigated. The hot-rolled Co-28Cr-6Mo-0.13N (mass%) alloy examined here exhibited a monotonic strength increment following hot-rolling reduction, eventually reaching a 0.2% proof stress of 1400 MPa while maintaining acceptable ductility (>10%). The dominant hot-rolling texture was a brass-type component, which is characterized by the alloy's peculiarly low stacking fault energy (SFE) even at hot rolling temperatures, although the minor peaks of the near copper component were also identified. However, because of the onset of dynamic recrystallization (DRX) during the hot rolling process, the texture intensity was relatively weak even after 90% hot rolling, although the grain refinement originating from the DRX was not significant (the "less active DRX" condition increased the strain accumulation during the process, resulting in high-strength samples). The weakened texture development resulted in negligible in-plane anisotropy for the hot-rolled specimen strength, when the specimens were tensile strained in the rolling direction (RD) and transverse direction (TD). The elongation-to-failure, however, exhibited a difference with respect to the tensile loading axis. It is suggested that the ductility anisotropy is closely related to a strain-induced γ (fcc) → ε (hcp) martensitic transformation during tensile loading, resulting in a difference in the proportion of quasi-cleavage fracture surfaces. The obtained results will be helpful in the development of high-strength Co-Cr-Mo alloy plates and sheets, and have implications regarding plastic deformation and texture evolution during the hot rolling of non-conventional metallic materials with low SFE at elevated temperatures, where planar dislocation slips of Shockley partial dislocations and thermally activated process interplay.

  16. Texture evolution and mechanical anisotropy of biomedical hot-rolled Co-Cr-Mo alloy.

    PubMed

    Mori, Manami; Yamanaka, Kenta; Sato, Shigeo; Chiba, Akihiko

    2015-11-01

    Crystallographic textures and their effect on the mechanical anisotropy of a hot-rolled biomedical Co-Cr-Mo alloy were investigated. The hot-rolled Co-28Cr-6Mo-0.13N (mass%) alloy examined here exhibited a monotonic strength increment following hot-rolling reduction, eventually reaching a 0.2% proof stress of 1400 MPa while maintaining acceptable ductility (>10%). The dominant hot-rolling texture was a brass-type component, which is characterized by the alloy's peculiarly low stacking fault energy (SFE) even at hot rolling temperatures, although the minor peaks of the near copper component were also identified. However, because of the onset of dynamic recrystallization (DRX) during the hot rolling process, the texture intensity was relatively weak even after 90% hot rolling, although the grain refinement originating from the DRX was not significant (the "less active DRX" condition increased the strain accumulation during the process, resulting in high-strength samples). The weakened texture development resulted in negligible in-plane anisotropy for the hot-rolled specimen strength, when the specimens were tensile strained in the rolling direction (RD) and transverse direction (TD). The elongation-to-failure, however, exhibited a difference with respect to the tensile loading axis. It is suggested that the ductility anisotropy is closely related to a strain-induced γ (fcc) → ε (hcp) martensitic transformation during tensile loading, resulting in a difference in the proportion of quasi-cleavage fracture surfaces. The obtained results will be helpful in the development of high-strength Co-Cr-Mo alloy plates and sheets, and have implications regarding plastic deformation and texture evolution during the hot rolling of non-conventional metallic materials with low SFE at elevated temperatures, where planar dislocation slips of Shockley partial dislocations and thermally activated process interplay. PMID:26275483

  17. Biofilm formation in a hot water system.

    PubMed

    Bagh, L K; Albrechtsen, H J; Arvin, E; Ovesen, K

    2002-01-01

    The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d(-1) to 2.3 d(-1)) than in the hot water tank (1.4 d(-1) to 2.2 d(-1)) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.

  18. Optimization of Plasmon Decay Through Scattering and Hot Electron Transfer

    NASA Astrophysics Data System (ADS)

    DeJarnette, Drew

    Light incident on metal nanoparticles induce localized surface oscillations of conductive electrons, called plasmons, which is a means to control and manipulate light. Excited plasmons decay as either thermal energy as absorbed phonons or electromagnetic energy as scattered photons. An additional decay pathway for plasmons can exist for gold nanoparticles situated on graphene. Excited plasmons can decay directly to the graphene as through hot electron transfer. This dissertation begins by computational analysis of plasmon resonance energy and bandwidth as a function of particle size, shape, and dielectric environment in addition to diffractive coupled in lattices creating a Fano resonance. With this knowledge, plasmon resonance was probed with incident electrons using electron energy loss spectroscopy in a transmission electron microscope. Nanoparticles were fabricated using electron beam lithography on 50 nanometer thick silicon nitride with some particles fabricated with a graphene layer between the silicon nitride and metal structure. Plasmon resonance was compared between ellipses on and off graphene to characterize hot electron transfer as a means of plasmon decay. It was observed that the presence of graphene caused plasmon energy to decrease by as much as 9.8% and bandwidth to increase by 25%. Assuming the increased bandwidth was solely from electron transfer as an additional plasmon decay route, a 20% efficiency of plasmon decay to graphene was calculated for the particular ellipses analyzed.

  19. Growth of chromium carbide in a hot wall DLICVD reactor.

    PubMed

    Boisselier, G; Maury, F; Schuster, F

    2011-09-01

    Chromium carbide coatings were grown at 748 K in a hot wall CVD reactor fed by sublimation of bis(benzene)chromium, BBC (MOCVD) and by direct liquid injection using a BBC/toluene solution (DLICVD). The two types of coatings exhibit an amorphous structure and the same C content (22 at.%). DLICVD permits delivering higher mass flow rate of precursors and consequently the growth rate is 3 times higher and the thickness uniformity is better than using MOCVD. Chromium metal deposition has also been investigated by DLICVD in this hot wall reactor using BBC/toluene/additive as precursor. The purpose of the additive is to block carbide formation. Two additives have been studied: (i) hexachlorobenzene (C6Cl6) and (ii) thiophenol (C6H5SH). The ratio additive/BBC required for Cr metal deposition is a few percent. In this process, C6Cl6 is not decomposed and only traces of Cl (0.4 at.%) are found in the coatings. For a ratio C6Cl6/BBC > 27% the growth of any coating is blocked. The gas phase containing C6H5SH is more reactive since the onset of deposition occurs approximately 50 K before the temperature of the chlorinated compound. Furthermore, a sulfur contamination of 3 at.% has been analyzed in the coatings revealing a partial decomposition of the additive. The results are detailed and discussed in relation with previous works. PMID:22097571

  20. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    2000-09-30

    DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests

  1. Hot-electron photodetection with a plasmonic nanostripe antenna.

    PubMed

    Chalabi, Hamidreza; Schoen, David; Brongersma, Mark L

    2014-03-12

    Planar metal-oxide-metal structures can serve as photodetectors that do not rely on the usual electron-hole pair generation in a semiconductor. Instead, absorbed light in one of the metals can produce a current of hot electrons when the incident photon energy exceeds the oxide barrier energy. Despite the desirable traits of convenient fabrication and room-temperature operation at zero bias of this type of device, the low power conversion efficiency has limited its use. Here, we demonstrate the benefits of reshaping one of the metallic contacts into a plasmonic stripe antenna. We use measurements of the voltage-dependence, spectral-dependence, stripe-width dependence, and polarization-dependence of the photocurrent to show that surface plasmon excitations can result in a favorable redistribution in the electric fields in the stripe that enhances the photocurrent. We also provide a theoretical model that quantifies the spectral photocurrent in terms of the electrical and optical properties of the junction. This model provides an accurate estimate of the bias dependence of the external quantum efficiency of different devices and shows that both the spatial and vectorial properties of the electric field distribution are important to its operation.

  2. Kinetics of hot-gas desulfurization sorbents for transport reactors

    SciTech Connect

    K.C. Kwon

    2000-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, to understand effects of space time of reaction gas mixtures on initial reaction kinetics of the sorbent-hydrogen sulfide system, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of MCRH-67 sorbent and AHI-1 was examined. These sorbents were obtained from the Research Triangle Institute (RTI). The sorbents in the form of 70 {micro}m particles are reacted with 1,000--4,000 ppm hydrogen sulfide at 450--600 C. The range of space time of reaction gas mixtures is 0.03--0.09 s. The range of reaction duration is 4--14,400 s.

  3. Ceramic hot-gas filter

    DOEpatents

    Connolly, E.S.; Forsythe, G.D.; Domanski, D.M.; Chambers, J.A.; Rajendran, G.P.

    1999-05-11

    A ceramic hot-gas candle filter is described having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during back pulse cleaning and is resistant to chemical degradation at high temperatures.

  4. Ceramic hot-gas filter

    DOEpatents

    Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

    1999-01-01

    A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

  5. Dynamics of hot rotating nuclei

    NASA Astrophysics Data System (ADS)

    Garcias, F.; de La Mota, V.; Remaud, B.; Royer, G.; Sébille, F.

    1991-02-01

    The deexcitation of hot rotating nuclei is studied within a microscopic semiclassical transport formalism. This framework allows the study of the competition between the fission and evaporation channels of deexcitation, including the mean-field and two-body interactions, without shape constraint for the fission channel. As a function of initial angular momenta and excitation energies, the transitions between three regimes is analyzed [particle evaporation, binary (ternary) fussion and multifragmentation], which correspond to well-defined symmetry breakings in the inertia tensor of the system. The competition between evaporation and binary fission is studied, showing the progressive disappearance of the fission process with increasing excitation energies, up to a critical point where nuclei pass directly from evaporation to multifragmentation channels.

  6. TRUEX hot demonstration. Final report

    SciTech Connect

    Chamberlain, D.B.; Leonard, R.A.; Hoh, J.C.; Gay, E.C.; Kalina, D.G.; Vandegrift, G.F.

    1990-04-01

    In FY 1987, a program was initiated to demonstrate technology for recovering transuranic (TRU) elements from defense wastes. This hot demonstration was to be carried out with solution from the dissolution of irradiated fuels. This recovery would be accomplished with both PUREX and TRUEX solvent extraction processes. Work planned for this program included preparation of a shielded-cell facility for the receipt and storage of spent fuel from commercial power reactors, dissolution of this fuel, operation of a PUREX process to produce specific feeds for the TRUEX process, operation of a TRUEX process to remove residual actinide elements from PUREX process raffinates, and processing and disposal of waste and product streams. This report documents the work completed in planning and starting up this program. It is meant to serve as a guide for anyone planning similar demonstrations of TRUEX or other solvent extraction processing in a shielded-cell facility.

  7. Hot electron production and heating by hot electrons in fast ignitor research

    SciTech Connect

    Key, M.H.; Estabrook, K.; Hammel, B.

    1997-12-01

    In an experimental study of the physics of fast ignition the characteristics of the hot electron source at laser intensities up to 10(to the 20th power) Wcm{sup -2} and the heating produced at depth by hot electrons have been measured. Efficient generation of hot electrons but less than the anticipated heating have been observed.

  8. Metal inks

    DOEpatents

    Ginley, David S; Curtis, Calvin J; Miedaner, Alex; van Hest, Marinus Franciscus Antonius Maria; Kaydanova, Tatiana

    2014-02-04

    Self-reducing metal inks and systems and methods for producing and using the same are disclosed. In an exemplary embodiment, a method may comprise selecting metal-organic (MO) precursor, selecting a reducing agent, and dissolving the MO precursor and the reducing agent in an organic solvent to produce a metal ink that remains in a liquid phase at room temperature. Metal inks, including self-reducing and fire-through metal inks, are also disclosed, as are various applications of the metal inks.

  9. Hot Dry Rock; Geothermal Energy

    SciTech Connect

    1990-01-01

    The commercial utilization of geothermal energy forms the basis of the largest renewable energy industry in the world. More than 5000 Mw of electrical power are currently in production from approximately 210 plants and 10 000 Mw thermal are used in direct use processes. The majority of these systems are located in the well defined geothermal generally associated with crustal plate boundaries or hot spots. The essential requirements of high subsurface temperature with huge volumes of exploitable fluids, coupled to environmental and market factors, limit the choice of suitable sites significantly. The Hot Dry Rock (HDR) concept at any depth originally offered a dream of unlimited expansion for the geothermal industry by relaxing the location constraints by drilling deep enough to reach adequate temperatures. Now, after 20 years intensive work by international teams and expenditures of more than $250 million, it is vital to review the position of HDR in relation to the established geothermal industry. The HDR resource is merely a body of rock at elevated temperatures with insufficient fluids in place to enable the heat to be extracted without the need for injection wells. All of the major field experiments in HDR have shown that the natural fracture systems form the heat transfer surfaces and that it is these fractures that must be for geothermal systems producing from naturally fractured formations provide a basis for directing the forthcoming but, equally, they require accepting significant location constraints on HDR for the time being. This paper presents a model HDR system designed for commercial operations in the UK and uses production data from hydrothermal systems in Japan and the USA to demonstrate the reservoir performance requirements for viable operations. It is shown that these characteristics are not likely to be achieved in host rocks without stimulation processes. However, the long term goal of artificial geothermal systems developed by systematic

  10. Carbon nanotube substrates and catalyzed hot stamp for polishing and patterning the substrates

    DOEpatents

    Wang, Yuhuang; Hauge, Robert H.; Schmidt, Howard K.; Kim, Myung Jong; Kittrell, W. Carter

    2009-09-08

    The present invention is generally directed to catalyzed hot stamp methods for polishing and/or patterning carbon nanotube-containing substrates. In some embodiments, the substrate, as a carbon nanotube fiber end, is brought into contact with a hot stamp (typically at 200-800.degree. C.), and is kept in contact with the hot stamp until the morphology/patterns on the hot stamp have been transferred to the substrate. In some embodiments, the hot stamp is made of material comprising one or more transition metals (Fe, Ni, Co, Pt, Ag, Au, etc.), which can catalyze the etching reaction of carbon with H.sub.2, CO.sub.2, H.sub.2O, and/or O.sub.2. Such methods can (1) polish the carbon nanotube-containing substrate with a microscopically smooth finish, and/or (2) transfer pre-defined patterns from the hot stamp to the substrate. Such polished or patterned carbon nanotube substrates can find application as carbon nanotube electrodes, field emitters, and field emitter arrays for displays and electron sources.

  11. Hot Electron-Based Near-Infrared Photodetection Using Bilayer MoS2.

    PubMed

    Wang, Wenyi; Klots, Andrey; Prasai, Dhiraj; Yang, Yuanmu; Bolotin, Kirill I; Valentine, Jason

    2015-11-11

    Recently, there has been much interest in the extraction of hot electrons generated from surface plasmon decay, as this process can be used to achieve additional bandwidth for both photodetectors and photovoltaics. Hot electrons are typically injected into semiconductors over a Schottky barrier between the metal and semiconductor, enabling generation of photocurrent with below bandgap photon illumination. As a two-dimensional semiconductor single and few layer molybdenum disulfide (MoS2) has been demonstrated to exhibit internal photogain and therefore becomes an attractive hot electron acceptor. Here, we investigate hot electron-based photodetection in a device consisting of bilayer MoS2 integrated with a plasmonic antenna array. We demonstrate sub-bandgap photocurrent originating from the injection of hot electrons into MoS2 as well as photoamplification that yields a photogain of 10(5). The large photogain results in a photoresponsivity of 5.2 A/W at 1070 nm, which is far above similar silicon-based hot electron photodetectors in which no photoamplification is present. This technique is expected to have potential use in future ultracompact near-infrared photodetection and optical memory devices.

  12. Spin-polarized lithium diffusion in a glass hot-vapor cell

    NASA Astrophysics Data System (ADS)

    Ishikawa, Kiyoshi

    2016-08-01

    We report diffusion coefficients of optically pumped lithium atoms in helium buffer gas. The free-induction decay and the spin-echo signals of ground-state atoms were optically detected in an external magnetic field with the addition of field gradient. Lithium hot vapor was produced in a borosilicate-glass cell at a temperature between 290 and 360°C. The simple setup using the glass cells enabled lithium atomic spectroscopy in a similar way to other alkali-metal atoms and study of the collisional properties of lithium atoms in a hot-vapor phase.

  13. The effect of fuel-to-air ratio on burner-rig hot corrosion

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.; Kohl, F. J.

    1978-01-01

    Samples of a cobalt-base alloy, Mar M-509, were subjected to hot corrosion in a Mach-0.3 burner rig. The corrodent was NaCl added as an aqueous solution to the combustion products of a sulfur-containing Jet-A fuel. The metal temperature was fixed at 900 C. The extent of hot corrosion increased by a factor of three as the fuel-to-air mass ratio was increased from 0.033 to 0.050. Because the depositing salt was always Na2SO4, the increased attack appeared to be related to the gas composition.

  14. Development the Methods for Preventing Hot Cracking With Use Analysis of Temperature Fields

    NASA Astrophysics Data System (ADS)

    Ol'khovik, Evgeniy

    2016-08-01

    The reasons for formation of hot cracks in steel castings having difficult geometric shape of a revolution body are discussed in the paper. Mathematical model for the calculation of metal castings solidification and analysis of temperature conditions, which determines the conditions of hot cracking formation are proposed. The advantage of developed model is ability to use only results of thermal analysis without special calculation of stress-strain state. Criteria for evaluating of thermal conditions for directional solidification and heat dissipation in mold is developed, what allowing to correct technology of casting for defects prevention.

  15. Elastic modulus of supercooled liquid and hot solid silicon measured by inelastic X-ray scattering

    SciTech Connect

    Alatas, A.; Said, A. H.; Sinn, H.; Alp, E. E.; Kodituwakku, C. N.; Reinhart, B.; Saboungi, M. -L.; Price, D. L.

    2005-12-01

    We measured the dynamical structure factors of supercooled-liquid and hot-solid silicon by inelastic X-ray scattering at the same temperature, 1620 K. Two significant changes in the averaged longitudinal sound velocities and in the longitudinal modulus are observed. We, first observe a different longitudinal modulus in the polycrystalline hot-solid silicon compared to the extrapolated value obtained from the single-crystal measurement. Furthermore, this reduction of the modulus may be a precursor of the semiconductor-to-metal transition. Second, the increase in the longitudinal modulus in the liquid upon supercooling is consistent with an increase in the degree of the directional bonding.

  16. Basics of Solar Heating & Hot Water Systems.

    ERIC Educational Resources Information Center

    American Inst. of Architects, Washington, DC.

    In presenting the basics of solar heating and hot water systems, this publication is organized from the general to the specific. It begins by presenting functional and operational descriptions of solar heating and domestic hot water systems, outlining the basic concepts and terminology. This is followed by a description of solar energy utilization…

  17. HotSpot Software Configuration Management Plan

    SciTech Connect

    Walker, H; Homann, S G

    2009-03-12

    This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  18. Variational Theory of Hot Dense Matter

    ERIC Educational Resources Information Center

    Mukherjee, Abhishek

    2009-01-01

    We develop a variational theory of hot nuclear matter in neutron stars and supernovae. It can also be used to study charged, hot nuclear matter which may be produced in heavy-ion collisions. This theory is a generalization of the variational theory of cold nuclear and neutron star matter based on realistic models of nuclear forces and pair…

  19. The Hot Hand Belief and Framing Effects

    ERIC Educational Resources Information Center

    MacMahon, Clare; Köppen, Jörn; Raab, Markus

    2014-01-01

    Purpose: Recent evidence of the hot hand in sport--where success breeds success in a positive recency of successful shots, for instance--indicates that this pattern does not actually exist. Yet the belief persists. We used 2 studies to explore the effects of framing on the hot hand belief in sport. We looked at the effect of sport experience and…

  20. The Time-Limited Hot Line.

    ERIC Educational Resources Information Center

    Loring, Marti Tamm; Wimberley, Edward T.

    1993-01-01

    Notes that media have become involved in creating programs and addressing issues that have been historically exclusive purview of mental health and human services agencies. Explains how time-limited hot line has been used to address specific issues raised by these programs. Provides overview of this type of hot line, offering triangular model of…

  1. 16 CFR 1505.51 - Hot surfaces.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Hot surfaces. 1505.51 Section 1505.51... CHILDREN Policies and Interpretations § 1505.51 Hot surfaces. (a) Test probe. Section 1505.6(g)(2) defines... inches long. To test for accessibility using this test probe, it shall be inserted no more than 3...

  2. 16 CFR 1505.51 - Hot surfaces.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Hot surfaces. 1505.51 Section 1505.51... CHILDREN Policies and Interpretations § 1505.51 Hot surfaces. (a) Test probe. Section 1505.6(g)(2) defines... inches long. To test for accessibility using this test probe, it shall be inserted no more than 3...

  3. 16 CFR 1505.51 - Hot surfaces.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Hot surfaces. 1505.51 Section 1505.51... CHILDREN Policies and Interpretations § 1505.51 Hot surfaces. (a) Test probe. Section 1505.6(g)(2) defines... inches long. To test for accessibility using this test probe, it shall be inserted no more than 3...

  4. 16 CFR 1505.51 - Hot surfaces.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Hot surfaces. 1505.51 Section 1505.51... CHILDREN Policies and Interpretations § 1505.51 Hot surfaces. (a) Test probe. Section 1505.6(g)(2) defines... inches long. To test for accessibility using this test probe, it shall be inserted no more than 3...

  5. "Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)

    MedlinePlus

    Facts About “Hot Tub Rash” and “Swimmer’s Ear” (Pseudomonas) What is Pseudomonas and how can it affect me? Pseudomonas (sue-doh- ... a major cause of infections commonly known as “hot tub rash” and “swimmer’s ear.” This germ is ...

  6. Hot Spot Removal System: System description

    SciTech Connect

    1997-09-01

    Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

  7. Hot-dry-rock feasibility study

    SciTech Connect

    Not Available

    1981-08-01

    The hot-dry-rock project tasks are covered as follows: hot-dry-rock reservoir; generation facilities; water resources; transmission requirements; environmental issues; government and community institutional factors; leasing, ownership and management of facilities; regulations, permits, and laws; and financial considerations. (MHR)

  8. Turbine Engine Hot Section Technology, 1985

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Turbine Engine Section Technology (HOST) Project Office of the Lewis Research Center sponsored a workshop to discuss current research pertinent to turbine engine hot section durability problems. Presentations were made concerning hot section environment and the behavior of combustion liners, turbine blades, and turbine vanes.

  9. Solar Energy for Space Heating & Hot Water.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This pamphlet reviews the direct transfer of solar energy into heat, particularly for the purpose of providing space and hot water heating needs. Owners of buildings and homes are provided with a basic understanding of solar heating and hot water systems: what they are, how they perform, the energy savings possible, and the cost factors involved.…

  10. Fracture toughness of hot-pressed beryllium

    NASA Technical Reports Server (NTRS)

    Lemon, D. D.; Brown, W. F., Jr.

    1985-01-01

    This paper presents the results of an investigation into the fracture toughness, sustained-load flaw growth, and fatigue-crack propagation resistance of S200E hot-pressed beryllium at room temperature. It also reviews the literature pertaining to the influence of various factors on the fracture toughness of hot-pressed beryllium determined using fatigue-cracked specimens.

  11. 16 CFR 1505.51 - Hot surfaces.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Hot surfaces. 1505.51 Section 1505.51... CHILDREN Policies and Interpretations § 1505.51 Hot surfaces. (a) Test probe. Section 1505.6(g)(2) defines accessibility, for certain paragraphs, as the ability to reach a heated surface with a 1/4-inch-diameter rod...

  12. METAL PHTHALOCYANINES

    DOEpatents

    Frigerio, N.A.

    1962-03-27

    A process is given for preparing heavy metal phthalocyanines, sulfonated or not. The process comprises mixing an inorganic metal salt with dimethyl formamide or methyl sulfoxide; separating the metal complex formed from the solution; mixing the complex with an equimolar amount of sodium, potassium, lithium, magnesium, or beryllium sulfonated or unsulfonated phthalocyanine whereby heavy-metal phthalocyanine crystals are formed; and separating the crystals from the solution. Uranyl, thorium, lead, hafnium, and lanthanide rare earth phthalocyanines can be produced by the process. (AEC)

  13. A silent epidemic of environmental metal poisoning?

    PubMed

    Nriagu, J O

    1988-01-01

    The main objective of this paper is to provoke and stimulate debate on the health effects of long-term, low-level exposure of human populations to toxic metals. Over one billion (10(9)) human guinea pigs are now being exposed to elevated levels of toxic metals and metalloids in the environment. The number of persons suffering from subclinical metal poisoning is believed to be several million. A large portion of the cases are in developed countries but the urban areas of developing countries have become 'hot-spots' of metal pollution, and the populations of such countries are particularly susceptible to environmental toxins. As a global problem, the potential health effects of metallic hazards should be a matter of public health concern, especially if the emissions of toxic metals into the environment continue at the current rate.

  14. User's Manual and Final Report for Hot-SMAC GUI Development

    NASA Technical Reports Server (NTRS)

    Yarrington, Phil

    2001-01-01

    A new software package called Higher Order Theory-Structural/Micro Analysis Code (HOT-SMAC) has been developed as an effective alternative to the finite element approach for Functionally Graded Material (FGM) modeling. HOT-SMAC is a self-contained package including pre- and post-processing through an intuitive graphical user interface, along with the well-established Higher Order Theory for Functionally Graded Materials (HOTFGM) thermomechanical analysis engine. This document represents a Getting Started/User's Manual for HOT-SMAC and a final report for its development. First, the features of the software are presented in a simple step-by-step example where a HOT-SMAC model representing a functionally graded material is created, mechanical and thermal boundary conditions are applied, the model is analyzed and results are reviewed. In a second step-by-step example, a HOT-SMAC model of an actively cooled metallic channel with ceramic thermal barrier coating is built and analyzed. HOT-SMAC results from this model are compared to recently published results (NASA/TM-2001-210702) for two grid densities. Finally, a prototype integration of HOTSMAC with the commercially available HyperSizer(R) structural analysis and sizing software is presented. In this integration, local strain results from HyperSizer's structural analysis are fed to a detailed HOT-SMAC model of the flange-to-facesheet bond region of a stiffened panel. HOT-SMAC is then used to determine the peak shear and peel (normal) stresses between the facesheet and bonded flange of the panel and determine the "free edge" effects.

  15. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  16. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2006-12-05

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  17. Metallic glasses.

    PubMed

    Greer, A L

    1995-03-31

    Amorphous metallic alloys, relative newcomers to the world of glasses, have properties that are unusual for solid metals. The metallic glasses, which exist in a very wide variety of compositions, combine fundamental interest with practical applications. They also serve as precursors for exciting new nanocrystalline materials. Their magnetic (soft and hard) and mechanical properties are of particular interest.

  18. Probing Hot Electron Flow Generated on Pt Nanoparticles with Au/TiO2 Schottky Diodes during Catalytic CO Oxidation

    SciTech Connect

    Park, Jeong Y.; Lee, Hyunjoo; Renzas, J. Russell; Zhang, Yawen; Somorjai, G.A.

    2008-05-01

    Hot electron flow generated on colloid platinum nanoparticles during exothermic catalytic carbon monoxide oxidation was directly detected with Au/TiO{sub 2} diodes. Although Au/TiO{sub 2} diodes are not catalytically active, platinum nanoparticles on Au/TiO{sub 2} exhibit both chemicurrent and catalytic turnover rate. Hot electrons are generated on the surface of the metal nanoparticles and go over the Schottky energy barrier between Au and TiO{sub 2}. The continuous Au layer ensures that the metal nanoparticles are electrically connected to the device. The overall thickness of the metal assembly (nanoparticles and Au thin film) is comparable to the mean free path of hot electrons, resulting in ballistic transport through the metal. The chemicurrent and chemical reactivity of nanoparticles with citrate, hexadecylamine, hexadecylthiol, and TTAB (Tetradecyltrimethylammonium Bromide) capping agents were measured during catalytic CO oxidation at pressures of 100 Torr O{sub 2} and 40 Torr CO at 373-513 K. We found that chemicurrent yield varies with each capping agent, but always decreases with increasing temperature. We suggest that this inverse temperature dependence is associated with the influence of charging effects due to the organic capping layer during hot electron transport through the metal-oxide interface.

  19. Hot workability of magnesium alloys

    NASA Astrophysics Data System (ADS)

    Mwembela, Aaron Absalom

    For the alloy AZ91 (Mg-9.OAl-0.7Zn-0.13Mn) die cast specimens were subjected to torsion testing at 150, 180, 240, 300, 420 and 450°C at 0.05 0.5 and 5.0 s--1 The as-cast specimens exhibited hot shortness at 360°C and above; however in that domain, after prior thermomechanical processing (TMP) at 300°C, they showed much improved properties (which were reported along with as-cast properties at 300°C and below). For AZ31-Mn (Mg-3.2Al-1-1Zn-0.34Mn), AZ31 (Mg-2-8Al-0-88Zn-0.01Mn), AZ63 (Mg-5-5Al-2.7Zn-0.34Mn) and ZK60 (Mg-5.7Zn-0.65Zr-O-O1A]), the specimens were subjected to hot torsion testing in the range 180 to 450°C and 0.01, 0.1, and 1.0 s--1. In the temperature range below 300°C flow curves rise to a peak with failure occurring immediately thereafter. Above 300°C the flow curves exhibited a peak and a gradual decline towards steady state. The temperature and strain rate dependence of the strength is described by a sinh-Arrhenius equation with QHW between 125 and 144 kJ/mol; this indicates control by climb in comparison with creep in the range 200--400°C. The alloy strength and activation energy declined in the order AZ63, AZ31-Mn AZ91, AZ31 and ZK60, while ductility increased with decreasing strength. In working of Mg alloys from 150 to 450°C, the flow curves harden to a peak and work soften to a steady state regime above 300°C. At temperatures below 300°C, twinning is observed initially to bring grains into more suitable slip orientations. At high T a substructure develops due to basal and prismatic slip, Forming cells of augmented misorientation first near the grain boundaries and later towards the grain cores. Near the peak, new grains appear along the old boundaries (mantle) as a result of dynamic recrystallization DRX but not in the core of the initial grains. As T rises, the new grains are larger and the mantle broader, enhanced DRX results in higher ductility. At intermediate T, shear bands form through alignment of mantle zones resulting in

  20. Structure of Hot Flow Anomaly

    NASA Astrophysics Data System (ADS)

    Shestakov, A.; Vaisberg, O. L.

    2012-12-01

    Hot Flow Anomalies (HFAs) were first discovered in 1980s. These are active processes of hot plasma bulks formation that usually occur at planetary bow shocks. Though HFA were studied for long time it is still not clear if they are reforming structures and what defines particular internal structure of HFA. Our study is based on the Interball Tail Probe data. We used 10-sec measurements of complex plasma analyzer SCA-1 and 1-second magnetic field measurements, and ELECTRON spectrometer 2-dimensional measurements with 3,75-sec temporal resolution. Five anomalies that were observed on the basis of well resolved structure for which we obtained displacement velocity along bow shock, flow velocities within HFA, and estimated the size. We checked if main criteria of HFA formation were fulfilled for each case. The following criteria were satisfied: motional electric field direction was directed toward current sheet at least at one side of it, bow shock was quasi-perpendicular at least at one side of HFA, and angle between current sheet normal and solar wind velocity was large. Convection velocities of plasma within HFA were calculated by subtracting average velocity from measured ion convection velocities along spacecraft trajectory through anomaly. These convection velocities viewed in coordinate system of shock normal and calculated IMF current sheet normal clearly show separation of HFA region in 3 parts: leading part, narrow central part, and trailing part. Ion velocity distributions confirm this triple structure of HFA. Thomsen et al. [1986] identified the region within HFA that they called "internal recovery". It looks like central region that we call narrow central part. Vaisberg et al. [1999] discussed separation of HFA into 2 distinct parts that correspond to leading and trailing parts. Judging from plasma convection pattern within HFAs we assumed that "internal recovery" region is the source of energy and momentum around interplanetary current sheet crossing. HFA

  1. Surface-plasmon enhanced photodetection at communication band based on hot electrons

    SciTech Connect

    Wu, Kai; Zhan, Yaohui E-mail: xfli@suda.edu.cn; Wu, Shaolong; Deng, Jiajia; Li, Xiaofeng E-mail: xfli@suda.edu.cn

    2015-08-14

    Surface plasmons can squeeze light into a deep-subwavelength space and generate abundant hot electrons in the nearby metallic regions, enabling a new paradigm of photoconversion by the way of hot electron collection. Unlike the visible spectral range concerned in previous literatures, we focus on the communication band and design the infrared hot-electron photodetectors with plasmonic metal-insulator-metal configuration by using full-wave finite-element method. Titanium dioxide-silver Schottky interface is employed to boost the low-energy infrared photodetection. The photodetection sensitivity is strongly improved by enhancing the plasmonic excitation from a rationally engineered metallic grating, which enables a strong unidirectional photocurrent. With a five-step electrical simulation, the optimized device exhibits an unbiased responsivity of ∼0.1 mA/W and an ultra-narrow response band (FWHM = 4.66 meV), which promises to be a candidate as the compact photodetector operating in communication band.

  2. 1. EXTERIOR VIEW OF BUILDING THAT HOUSES THE HOT ROLL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR VIEW OF BUILDING THAT HOUSES THE HOT ROLL MILL, ALSO KNOWN AS THE NO. 31 HOT ROLL MILL; LOOKING SOUTHWEST - American Brass Company, Kenosha Works, Hot Roll Mill, Kenosha, Kenosha County, WI

  3. Cancer treatment: dealing with hot flashes and night sweats

    MedlinePlus

    ... ency/patientinstructions/000826.htm Cancer treatment: dealing with hot flashes and night sweats To use the sharing ... JavaScript. Certain types of cancer treatments can cause hot flashes and night sweats. Hot flashes are when ...

  4. Bayesian Inference of the Composition and Inflation Power of Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel Peter; Fortney, Jonathan J.

    2016-10-01

    The radius of a planet for a given mass is the result of its composition and thermal evolutionary history. For cooler giants, where thermal evolution is relatively well-understood, we can infer a planet's bulk composition from its mass, radius, stellar insolation and age, since all being equal, more metal-rich planets are smaller and denser. For inflated hot giants, there is a degeneracy between inferred composition and inflation power. Within a Bayesian framework we examine both groups, beginning with the cool giant planets. Among these, we observe that the internal heavy-element mass correlates well with the total planet mass, and the metal enrichment relative to the parent star is correlated negatively with planet mass. However, it appears that there is not a simple relation between the planet heavy-element mass and stellar metallicity. These fundamental "mass-metallicity" results are consistent with the core accretion model of planet formation. For the hotter inflated gas giants, we estimate the functional dependence of inflation power on stellar insolation by demanding that the same metal to mass relation applies to both cold and hot gas giants. We consider various forms for this relation and the resulting outliers. This inflation power result is robust to assumptions about metal placement within the planet and equation of state because it relies only on matching the two groups of planets. These results serve as a new way to connect models of planet inflation to existing observations of giant planets.

  5. Hot Leg Piping Materials Issues

    SciTech Connect

    V. Munne

    2006-07-19

    With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the space nuclear power plant (SNPP) for Project Prometheus (References a and b) the reactor outlet piping was recognized to require a design that utilizes internal insulation (Reference c). The initial pipe design suggested ceramic fiber blanket as the insulation material based on requirements associated with service temperature capability within the expected range, very low thermal conductivity, and low density. Nevertheless, it was not considered to be well suited for internal insulation use because its very high surface area and proclivity for holding adsorbed gases, especially water, would make outgassing a source of contaminant gases in the He-Xe working fluid. Additionally, ceramic fiber blanket insulating materials become very friable after relatively short service periods at working temperatures and small pieces of fiber could be dislodged and contaminate the system. Consequently, alternative insulation materials were sought that would have comparable thermal properties and density but superior structural integrity and greatly reduced outgassing. This letter provides technical information regarding insulation and materials issues for the Hot Leg Piping preconceptual design developed for the Project Prometheus space nuclear power plant (SNPP).

  6. Thermal conductivity of metals

    NASA Technical Reports Server (NTRS)

    Kazem, Sayyed M.

    1990-01-01

    The objective is to familiarize students with steady and unsteady heat transfer by conduction and with the effect of thermal conductivity upon temperature distribution through a homogeneous substance. The elementary heat conduction experiment presented is designed for associate degree technology students in a simple manner to enhance their intuition and to clarify many confusing concepts such as temperature, thermal energy, thermal conductivity, heat, transient and steady flows. The equipment set is safe, small, portable (10 kg) and relatively cheap (about $1200): the electric hot plate 2 kg (4.4 lb) for $175: the 24 channel selector and Thermocouple Digital Readout (Trendicator) 4.5 kg (10 lb) for about $1000; the three metal specimens (each of 2.5 cm diameter and 11 cm length), base plate and the bucket all about 3 kg (7 lb) for about $25. The experiment may take from 60 to 70 minutes. Although the hot plate surface temperature could be set from 90 to 370 C (maximum of 750 watts) it is a good practice to work with temperatures of 180 to 200 C (about 400 watts). They may experiment in squads of 2, 3 or even 4, or the instructor may demonstrate it for the whole class.

  7. The Early Phases of the Evolution of Hot Helium Cores

    NASA Astrophysics Data System (ADS)

    Nelson, L. A.; MacCannell, K.

    2000-10-01

    We examine the evolution of close binary systems containing a mass accreting compact object and a post-main-sequence donor. Using the best available input physics, we have calculated the evolutionary tracks of these systems for a wide range of metallicities and evolutionary states of the donor star (i.e., when it first starts to lose mass to its compact companion). Assuming that a sufficiently massive helium core has formed within the donor at the onset of mass transfer, the donor will be stripped of its hydrogen-rich envelope and will rapidly evolve from a cool "giant" to a relatively hot, compact object composed almost entirely of helium. Mass transfer ceases and these objects are destined to cool forever to become fully electron-degenerate helium dwarfs. A number of helium dwarfs have recently been discovered in isolation and in binary systems. We have established the range of initial conditions of the progenitors of these helium dwarfs for a wide array of core masses and metallicities. While this range of variations (for a fixed mass and metallicity) becomes unimportant to the observable properties of old helium dwarfs that have had a long time to cool, it is quite significant for young dwarfs that are quite luminous and are likely to be preferentially selected in any observational survey. This work was supported in part by the Natural Sciences and Engineering Research Council (NSERC) of Canada.

  8. Evolution of Metals

    NASA Astrophysics Data System (ADS)

    Shull, J. M.

    1998-05-01

    This review will cover a mystery story. Actually, two mysteries of the Structure and Evolution of the Universe involving the history of the baryons and the chemical elements synthesized in the first stars. When did the gas and metals first form? How did they evolve to their current distribution? The original crime scene is unknown, but evidence has been collected in the diffuse intergalactic medium and in hot intracluster gas. In these scattered locales, large amounts of gas has accumulated, contaminated by heavy elements from the first stars. Unfortunately, some of the evidence has been destroyed by gravity. Also, the earliest quasars, massive stars, and supernovae altered the physical state of the gas and transported the elements far from the original scene. I will briefly review current observations and theories relevant to these processes and suggest ways in which future NASA missions could constrain the many speculative ideas on this subject.

  9. Interaction of Burning Metal Particles

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.; Berman, Charles H.; Hoffmann, Vern K.

    1999-01-01

    Physical characteristics of the combustion of metal particle groups have been addressed in this research. The combustion behavior and interaction effects of multiple metal particles has been studied using a microgravity environment, which presents a unique opportunity to create an "aerosol" consisting of relatively large particles, i.e., 50-300 micrometer diameter. Combustion behavior of such an aerosol could be examined using methods adopted from well-developed single particle combustion research. The experiment included fluidizing relatively large (order of 100 micrometer diameter) uniform metal particles under microgravity and igniting such an "aerosol" using a hot wire igniter. The flame propagation and details of individual particle combustion and particle interaction have been studied using a high speed movie and video-imaging with cameras coupled with microscope lenses to resolve individual particles. Interference filters were used to separate characteristic metal and metal oxide radiation bands form the thermal black body radiation. Recorded flame images were digitized and employed to understand the processes occurring in the burning aerosol. The development of individual particle flames, merging or separation, and extinguishing as well as induced particle motion have been analyzed to identify the mechanisms governing these processes. Size distribution, morphology, and elemental compositions of combustion products were characterized and used to link the observed in this project aerosol combustion phenomena with the recently expanded mechanism of single metal particle combustion.

  10. Interaction of Burning Metal Particles

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.; Berman, Charles H.; Hoffmann, Vern K.

    1999-01-01

    Physical characteristics of the combustion of metal particle groups have been addressed in this research. The combustion behavior and interaction effects of multiple metal particles has been studied using a microgravity environment, which presents a unique opportunity to create an "aerosol" consisting of relatively large particles, i.e., 50-300 m diameter. Combustion behavior of such an aerosol could be examined using methods adopted from well-developed single particle combustion research. The experiment included fluidizing relatively large (order of 100 m diameter) uniform metal particles under microgravity and igniting such an "aerosol" using a hot wire igniter. The flame propagation and details of individual particle combustion and particle interaction have been studied using a high speed movie and video-imaging with cameras coupled with microscope lenses to resolve individual particles. Interference filters were used to separate characteristic metal and metal oxide radiation bands from the thermal black body radiation. Recorded flame images were digitized and various image processing techniques including flame position tracking, color separation, and pixel by pixel image comparison were employed to understand the processes occurring in the burning aerosol. The development of individual particle flames, merging or separation, and extinguishment as well as induced particle motion have been analyzed to identify the mechanisms governing these processes. Size distribution, morphology, and elemental compositions of combustion products were characterized and used to link the observed in this project aerosol combustion phenomena with the recently expanded mechanism of single metal particle combustion.

  11. Pore structure and reactivity changes in hot coal gas desulfurization sorbents. Final report, September 1987--January 1991

    SciTech Connect

    Sotirchos, S.V.

    1991-05-01

    The primary objective of the project was the investigation of the pore structure and reactivity changes occurring in metal/metal oxide sorbents used for desulfurization of hot coal gas during sulfidation and regeneration, with particular emphasis placed on the effects of these changes on the sorptive capacity and efficiency of the sorbents. Commercially available zinc oxide sorbents were used as model solids in our experimental investigation of the sulfidation and regeneration processes.

  12. How Hot Can Venus Get?

    NASA Astrophysics Data System (ADS)

    Bullock, Mark A.; Grinspoon, David H.

    2001-11-01

    The powerful greenhouse effect on Venus exists because pressure-broadened CO2 absorption bands, interlaced with water absorption features, effectively block most of the upwelling thermal radiation coming from the surface. The sulfuric acid clouds and small amounts of SO2, OCS, CO, HCl and HF are responsible for some absorption of radiation at wavelengths greater than 2 μ m. In particular, these constituents of Venus' atmosphere absorb thermal radiation in a crucial part of the spectrum -- the 2.1 to 2.6 μ m range where the CO2-H2O thermal absorption conspiracy is weak. Much of the radiation on the short-wavelength side of Venus' surface blackbody curve (which has a peak at 4 μ m), leaves the planet through this window. Variations in the abundance of the trace atmospheric species have a large effect on the efficacy of this window, both directly through their infrared absorption, and indirectly through their effect on clouds. Increased atmospheric absorption, say through an increase in atmospheric water abundance, can heat the surface. However, as the surface of Venus heats up, the peak of its Planck function moves towards the 2.1 to 2.6 μ m window, allowing more direct thermal radiation loss to space. This high temperature shift of radiative loss into the window will act as a thermostat. For moderate perturbations in atmospheric trace species therefore, such as those expected from volcanism or large impacts, there is a limit to how hot the surface of Venus can get. Using a one-dimensional, non-gray coupled cloud/radiative transfer model, we will show what the theoretical limits on the surface temperature of Venus are. We will discuss the fairly broad constraints on these conclusions, and make some general predictions for terrestrial planets with CO2-H2O atmospheres in other solar systems. These results may be relevant for models of tectonic and convective history of Venus and other planets.

  13. Hot water immersion for bluebottle stings.

    PubMed

    2013-06-01

    Hot water immersion can be used to treat bluebottle (Physalia spp.) stings. Bluebottle stings are most common in non-tropical areas and can be very painful. After initial management, hot water (ideally at 42-45°C) applied to the site of the sting for 30-90 minutes can be used to manage pain. If hot water is unavailable, a heat pack may provide an accessible alternative. Hot water application for bluebottle stings has NHMRC Level 2 evidence of efficacy. The most common adverse effect is that the patient cannot tolerate the heat, and there has been one case of a thermal burn reported. This article forms part of a series on non-drug treatments, which summarise the indications, considerations and the evidence, and where clinicians and patients can find further information.

  14. Phage Community Dynamics in Hot Springs

    PubMed Central

    Breitbart, Mya; Wegley, Linda; Leeds, Steven; Schoenfeld, Tom; Rohwer, Forest

    2004-01-01

    In extreme thermal environments such as hot springs, phages are the only known microbial predators. Here we present the first study of prokaryotic and phage community dynamics in these environments. Phages were abundant in hot springs, reaching concentrations of a million viruses per milliliter. Hot spring phage particles were resistant to shifts to lower temperatures, possibly facilitating DNA transfer out of these extreme environments. The phages were actively produced, with a population turnover time of 1 to 2 days. Phage-mediated microbial mortality was significant, making phage lysis an important component of hot spring microbial food webs. Together, these results show that phages exert an important influence on microbial community structure and energy flow in extreme thermal environments. PMID:15006788

  15. Design data brochure: Solar hot water system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A design calculation is detailed for a single-family residence housing a family of four in a nonspecific geographical area. The solar water heater system is designed to provide 80 gallons of 140 F hot water per day.

  16. Design data brochure: Solar hot air heater

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design, installation, performance, and application of a solar hot air heater for residential, commercial and industrial use is reported. The system has been installed at the Concho Indian School in El Reno, Oklahoma.

  17. Prototype solar heating and hot water systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Progress made in the development of a solar hot water and space heating system is described in four quarterly reports. The program schedules, technical status and other program activities from 6 October 1976 through 30 September 1977 are provided.

  18. Diagenetic Changes in Common Hot Spring Microfacies

    NASA Astrophysics Data System (ADS)

    Hinman, N. W.; Kendall, T. A.; MacKenzie, L. A.; Cady, S. D.

    2016-05-01

    The friable nature of silica hot spring deposits makes them susceptible to mechanical weathering. Rapid diagenesis must take place for these rocks to persist in the geologic record. The properties of two microfacies at two deposits were compared.

  19. Dust filtration in hot coal gas

    SciTech Connect

    Schreurs, H.C.E.

    1995-12-31

    Cleaning up coal gas at high temperatures means a fundamental change to the complete system of an Integrated Coal Gasification Combined Cycle. Coal ash is one of the components that asks for a complete different kind of treating. Several types of dust filtration are available for cleaning up hot coal gas. Several difficulties arise when cleaning up hot coal gas for dust. The paper will deal with the possibilities of the dust cleaning (place, technics), the difficulties (material, efficiencies, residue handling) and the cleaning conditions. It will given an overview of the boundary conditions of dust filtration with respect to slag and ash formation in the gasifier and the coal gas treatment and use after the filtration. Evaluation will show the development path for hot dust filtration, divided into several steps for correct risk analysis. Both former system and feasibility studies on hot gas clean up and ongoing studies and research, all conducted under Novem-assignment, will be reported on.

  20. Alternative Energy Sources for Heating the Stratospheres of Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Marley, Mark S.; Zahnle, K.; Freedman, R.; Lodders, K.; Fortney, J.

    2009-09-01

    Spitzer Space Telescope observations have constrained the atmospheric thermal structure of many transiting extrasolar giant planets. Many of these planets, like their solar system cousins, apparently have hot stratospheres. It has been suggested that absorption in the optical by gaseous TiO and VO provides the necessary energy source to power their thermal emission. While this mechanism is certainly plausible in the hottest Jupiters, temperature inversions have also been observed in cooler planets in which TiO and VO should be condensed into grains. Motivated by the importance of photochemistry in producing important atmospheric absorbers in the solar system, we have explored the role of atmospheric sulfur photochemistry in hot Jupiter atmospheres. Our photochemical kinetics code was previously used to study various problems in solar system, including the aftermath of the S/L-9 impacts into Jupiter. We find that the optically active gases S2 and HS (mercapto) are generated photochemically and thermochemically at T > 1200 K from H2S with peak abundances between 1 and 10 mbar. S2 absorbs UV between 240 and 340 nm and is optically thick for metallicities higher than solar. HS is generally more abundant than S2 and absorbs between 300 and 460 nm. Together these species play an important role in the stratospheric energy budget of hot Jupiters and may provide a mechanism for producing temperature inversions under conditions where gaseous TiO and VO are not present. At lower temperatures, below 1200 K, we find that the atmospheric chemistry enters a different domain where the production of soots may be favored. Such soots may be responsible for the haze detected in the atmosphere of HD189733 and may also play a role in the stratospheric energy budgets of cooler planets.

  1. Applications of nanoimprint lithography/hot embossing: a review

    NASA Astrophysics Data System (ADS)

    Chen, Yifang

    2015-11-01

    This review concentrates on the applications of nanoimprint lithography (NIL) and hot embossing for the fabrications of nanolectronic devices, nanophotonic metamaterials and other nanostructures. Technical challenges and solutions in NIL such as nanofabrication of templates, removal of residual resist, pattern displacement in thermal NIL arising from thermal expansion are first discussed. In the nanofabrication of templates, dry etch in plasma for the formation of multi-step structures and ultra-sharp tip arrays in silicon, nanophotonic chiral structures with high aspect ratio in SiC are demonstrated. A bilayer technique for nondestructive removal of residual resist in thermal NIL is described. This process is successfully applied for the fabrication of T-shape gates and functional high electron mobility transistors. However, pattern displacement intrinsically existing in thermal NIL/hot embossing owing to different thermal expansions in the template and substrate, respectively, limits its further development and scale-up. Low temperature even room temperature NIL (RTNIL) was then proposed on HSQ, trying to eliminate the pattern distortion by avoiding a thermal loop in the imprint. But, considerable pressure needed in RTNIL turned the major attentions to the development of UV-curing NIL in UV-curable monomers at low temperature. A big variety of applications by low-temperature UV-curing NIL in SU-8 are described, including high-aspect-ratio phase gratings, tagging technology by nanobarcode for DNA sequencing, nanofluidic channels, nanophotonic metamaterials and biosensors. Hot embossing, as a parallel technique to NIL, was also developed, and its applications on ferroelectric polymers as well as metals are reviewed. Therefore, it is necessary to emphasize that this review is mainly attempted to review the applications of NIL/embossing instead of NIL technique advances.

  2. HotSpot Health Physics Codes

    SciTech Connect

    Homann, S. G.

    2013-04-18

    The HotSpot Health Physics Codes were created to provide emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating insidents involving redioactive material. The software is also used for safety-analysis of facilities handling nuclear material. HotSpot provides a fast and usually conservative means for estimation the radiation effects associated with the short-term (less than 24 hours) atmospheric release of radioactive materials.

  3. The hot spot of vegetation canopies

    NASA Technical Reports Server (NTRS)

    Myneni, Ranga B.; Kanemasu, Edward T.

    1988-01-01

    A conventional radiometer is used to identify the hot spot (the peak in reflected radiation in the retrosolar direction) of vegetation. A multiwavelength-band radiometer collected radiances on fully grown dense wheat and maize canopies on several clear sunny days. It is noted that the hot spot is difficult to detect in the near IR wavelengths because the shadows are much darker. In general, the retrosolar brightness is found to be higher for smaller sun polar angles than for larger angles.

  4. HotSpot Health Physics Codes

    2010-03-02

    The HotSpot Health Physics Codes were created to provide emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating incidents involving radioactive material. The software is also used for safety-analysis of facilities handling nuclear material. HotSpot provides a fast and usually conservative means for estimation the radiation effects associated with the short-term (less than 24 hours) atmospheric release of radioactive materials.

  5. Hot electron generation by aluminum oligomers in plasmonic ultraviolet photodetectors.

    PubMed

    Ahmadivand, Arash; Sinha, Raju; Vabbina, Phani Kiran; Karabiyik, Mustafa; Kaya, Serkan; Pala, Nezih

    2016-06-13

    We report on an integrated plasmonic ultraviolet (UV) photodetector composed of aluminum Fano-resonant heptamer nanoantennas deposited on a Gallium Nitride (GaN) active layer which is grown on a sapphire substrate to generate significant photocurrent via formation of hot electrons by nanoclusters upon the decay of nonequilibrium plasmons. Using the plasmon hybridization theory and finite-difference time-domain (FDTD) method, it is shown that the generation of hot carriers by metallic clusters illuminated by UV beam leads to a large photocurrent. The induced Fano resonance (FR) minimum across the UV spectrum allows for noticeable enhancement in the absorption of optical power yielding a plasmonic UV photodetector with a high responsivity. It is also shown that varying the thickness of the oxide layer (Al2O3) around the nanodisks (tox) in a heptamer assembly adjusted the generated photocurrent and responsivity. The proposed plasmonic structure opens new horizons for designing and fabricating efficient opto-electronics devices with high gain and responsivity. PMID:27410381

  6. Service failure of hot-stage turbine blades:

    NASA Astrophysics Data System (ADS)

    Oldfield, William; Oldfield, Freda M.

    1993-10-01

    Surface-connected porosity in current military aircraft hot-stage turbine engine blades is associated with blade failure. Oxidation ratcheting is suggested as the failure mechanism. Sta- tistical comparison of new and used blade populations showed that for blades cast with an equiaxed structure, the porosity in new blades was associated with crack formation on the con- cave surface of the used blades. The pores did not tend to develop into cracks on the compressed (convex) surface of the blade. Insufficient suitable data on directionally solidified blades pre- vented similar statistical correlations. However, metallography of the directionally solidified blades showed that the in-service cracks were related to oxidation inside surface-connected pores and that the cracks were oriented in the same direction as the (axial) casting pores. Thus, the proposed failure mechanism through ratcheting is based on the following insights: (1) the blades are thermally cycled as a normal part of service; (2) the hot blades expand and the open pores are filled with oxide; (3) when the blade is cooled, thermal contraction of the metal is greater than the oxide, causing compressive stress and yield; and (4) thermal expansion of the blades opens the pores again, since yield relaxed compressive stress at low temperature. These insights were supported by metallographic and computer-simulation studies which showed that the pores grow 20 to 50 pct in width per 100 missions (about 90 hours of operation) for a military aircraft on a typical mission profile.

  7. Hot Corrosion at Air-Ports in Kraft Recovery Boilers

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Russell, James H.

    2003-01-01

    Hot corrosion can occur on the cold-side of airports in Kraft recovery boilers. The primary corrosion mechanism involves the migration of sodium hydroxide and potassium hydroxide vapors through leaks in the furnace wall at the airports and their subsequent condensation. It has been reported that stainless steel is attacked much faster than carbon steel in composite tubes, and that carbon steel tubing, when used with a low-chromium refractory, does not exhibit this type of corrosion. For hot corrosion fluxing of metal oxides, either acidic or basic fluxing takes place, with a solubility minimum at the basicity of transition between the two reactions. For stainless steel, if the basicity of the fused salt is between the iron and chromium oxide solubility minima, then a synergistic effect can occur that leads to rapid corrosion. The products of one reaction are the reactants of the other, which eliminates the need for rate-controlling diffusion. This effect can explain why stainless steel is attacked more readily than carbon steel.

  8. Advances in Ammonia Removal from Hot Coal Gas

    SciTech Connect

    Jothimurugesan, K.; Gangwal, S.K.

    1996-12-31

    Nitrogen occurs in coal in the form of tightly bound organic ring compounds, typically at levels of 1 to 2 wt%. During coal gasification, this fuel bound nitrogen is released principally as ammonia (NH{sub 3}). When hot coal gas is used to generate electricity in integrated gasification combined cycle (IGCC) power plants, NH{sub 3} is converted to nitrogen oxides (NO{sub x}) which are difficult to remove and are highly undesirable as atmospheric pollutants. Similarly, while the efficiency of integrated gasification molten carbonate fuel cell (IGFC) power plants is not affected by NH{sub 3}, NO{sub x} is generated during combustion of the anode exhaust gas. Thus NH{sub 3} must be removed from hot coal gas before it can be burned in a turbine or fuel cell. The objective of this study is to develop a successful combination of an NH{sub 3} decomposition catalyst with a zinc-based mixed-metal oxide sorbent so that the sorbent-catalyst activity remains stable for NH{sub 3} decomposition in addition to H{sub 2}S removal under cycle sulfidation-regeneration conditions in the temperature range of 500 to 750{degrees}C.

  9. Hot electron generation by aluminum oligomers in plasmonic ultraviolet photodetectors.

    PubMed

    Ahmadivand, Arash; Sinha, Raju; Vabbina, Phani Kiran; Karabiyik, Mustafa; Kaya, Serkan; Pala, Nezih

    2016-06-13

    We report on an integrated plasmonic ultraviolet (UV) photodetector composed of aluminum Fano-resonant heptamer nanoantennas deposited on a Gallium Nitride (GaN) active layer which is grown on a sapphire substrate to generate significant photocurrent via formation of hot electrons by nanoclusters upon the decay of nonequilibrium plasmons. Using the plasmon hybridization theory and finite-difference time-domain (FDTD) method, it is shown that the generation of hot carriers by metallic clusters illuminated by UV beam leads to a large photocurrent. The induced Fano resonance (FR) minimum across the UV spectrum allows for noticeable enhancement in the absorption of optical power yielding a plasmonic UV photodetector with a high responsivity. It is also shown that varying the thickness of the oxide layer (Al2O3) around the nanodisks (tox) in a heptamer assembly adjusted the generated photocurrent and responsivity. The proposed plasmonic structure opens new horizons for designing and fabricating efficient opto-electronics devices with high gain and responsivity.

  10. Two Hot Jupiters from K2 Campaign 4

    NASA Astrophysics Data System (ADS)

    Johnson, Marshall C.; Gandolfi, Davide; Fridlund, Malcolm; Csizmadia, Szilard; Endl, Michael; Cabrera, Juan; Cochran, William D.; Deeg, Hans J.; Grziwa, Sascha; Ramírez, Ivan; Hatzes, Artie P.; Eigmüller, Philipp; Barragán, Oscar; Erikson, Anders; Guenther, Eike W.; Korth, Judith; Kuutma, Teet; Nespral, David; Pätzold, Martin; Palle, Enric; Prieto-Arranz, Jorge; Rauer, Heike; Saario, Joonas

    2016-06-01

    We confirm the planetary nature of two transiting hot Jupiters discovered by the Kepler spacecraft’s K2 extended mission in its Campaign 4, using precise radial velocity measurements from FIES@NOT, HARPS-N@TNG, and the coudé spectrograph on the McDonald Observatory 2.7 m telescope. K2-29 b (EPIC 211089792b) transits a K1V star with a period of 3.2589263 ± 0.0000015 days; its orbit is slightly eccentric (e={0.084}-0.023+0.032). It has a radius of {R}P={1.000}-0.067+0.071 RJ and a mass of {M}P={0.613}-0.026+0.027 MJ. Its host star exhibits significant rotational variability, and we measure a rotation period of {P}{rot}=10.777+/- 0.031 days. K2-30 b (EPIC 210957318 b) transits a G6V star with a period of 4.098503 ± 0.000011 days. It has a radius of {R}P={1.039}-0.051+0.050 RJ and a mass of {M}P={0.579}-0.027+0.028 MJ. The star has a low metallicity for a hot Jupiter host, [{Fe}/{{H}}]=-0.15+/- 0.05.

  11. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    NASA Astrophysics Data System (ADS)

    Miller, Matthew J.; Hodges-Kluck, Edmund J.; Bregman, Joel N.

    2016-02-01

    Detections of z ≈ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot (˜ {10}6 K), low-density plasma extending ≳ 50 {{kpc}} into the Mily Way’s halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the O vii Kα absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight line pulsar dispersion measure and O vii equivalent width to show the average gas metallicity is ≳ 0.6{Z}⊙ and b ≳ 100 km s-1. Determining these properties offers valuable insights into the dynamical state of the Milky Way’s hot gas, and improves the line strength interpretation. We discuss future strategies to observe these effects with an instrument that has a spectral resolution of about 3000, a goal that is technically possible today.

  12. Semiconductor-free hot carrier devices for energy harvesting and photodetection

    NASA Astrophysics Data System (ADS)

    Gong, Tao; Munday, Jeremy

    The maximum efficiency for a single-junction solar cell is around 30% by the Shockley-Queisser (SQ) limit. The energy loss is typically through a thermalization process between the excited high-energy carriers, e.g. hot carriers, and the lattice. Therefore, the collection of the hot carriers before thermalization would allow for reduced power loss. Recently, photodetectors based on metal-semiconductor Schottky junctions have been exploiting hot electron effects to allow sub-bandgap absorption and hence show promise as near IR wavelength detectors. Here we present a simple, semiconductor-free hot carrier device based on transparent conducting oxides (TCO) electrodes. We experimentally demonstrate the hot carrier generation and extraction under monochromatic and broadband light illumination of normal and oblique incidence. Under optimized conditions, a power conversion efficiency >10% is predicted for high-energy photon excitation. The performance of the device shows further improvement by employing nanostructures, which couple the incident light into surface plasmons, leading to absorption enhancement. This semiconductor-free device provides an alternative way of energy harvesting and photodetection.

  13. Hot gas cleanup for molten carbonate fuel cells. A zinc oxide reactor model, Final report

    SciTech Connect

    Steinfeld, G.

    1980-09-16

    Utilization of coal gasifiers to power MCFC requires a cleanup system to remove sulfur and particulates. Of the two near term options available for desulfurization of gasifier effluent, namely low temperature cleanup utilizing absorber/stripper technology, and hot gas cleanup utilizing metal oxides, there is a clear advantage to using hot gas cleanup. Since the MCFC will operate at 1200/sup 0/F, and the gasifier effluent could be between 1200 to 1900/sup 0/F, a hot gas cleanup system will require little or no change in process gas temperature, thereby contributing to a high overall system efficiency. A hot gas cleanup system will consist of FeO for bulk H/sub 2/S removal and ZnO for reduction of H/sub 2/S to sub ppM levels. Hot gas cleanup systems at present are not available commercially, and therefore it is the objective of this project to model the components of the system in order to help bring this technology closer to commercialization, by providing simulated operating characteristics to aid in system design, and system simulations of gasifier/MCFC systems. The modeling of the ZnO reactor is presented.

  14. Concentrator hot-spot testing, phase 1

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.

    1987-01-01

    Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator module hot-spot qualification test is the test developed for flat-plate modules, issues, such as providing cell illumination, introduce additional complexities into the testing procedure. The same general guidelines apply for protecting concentrator modules from hot-spot stressing as apply to flat-plate modules. Therefore, recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. In addition, a new method for determining the cell temperature in the laboratory or in the field is discussed.

  15. Multifrequency multi-qubit entanglement based on plasmonic hot spots

    PubMed Central

    Ren, Jun; Wu, Tong; Zhang, Xiangdong

    2015-01-01

    The theoretical method to study strong coupling between an ensemble of quantum emitters (QEs) and surface plasmons excited by the nanoparticle cluster has been presented by using a rigorous first-principles electromagnetic Green’s tensor technique. We have demonstrated that multi-qubit entanglements for two-level QEs can be produced at different coupling resonance frequencies, when they locate in the hot spots of the metallic nanoparticle cluster. The duration of quantum beats for such an entanglement can reach two orders longer than that for the entanglement in a photonic cavity. The phenomenon originates from collective coupling resonance excitation of the cluster. At the frequency of single scattering resonance, the entanglement cannot be produced although the single QE spontaneous decay rate is very big. PMID:26350051

  16. Core Deuterium Fusion and Radius Inflation in Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Jaikumar, Prashanth; Rachid Ouyed

    2016-06-01

    Several laboratory-based studies have shown that the Deuterium fusion cross-section is enhanced in a solid deuterated target as compared to a gas target, attributable to enhanced mobility of deuterons in a metal lattice. As an application, we propose that, for core temperatures and compositions characterizing hot Jupiters, screened Deuterium fusion can occur deep in the interior, and show that the amount of radius inflation from this effect can be important if there is sufficient rock-ice in the core. The mechanism of screened Deuterium fusion, operating in the above temperature range, is generally consistent with the trend in radius anomaly with planetary equilibrium temperature. We also explore the trend with planetary mass using a simple analytic model.

  17. Reusable Metallic Thermal Protection Systems Development

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.; Martin, Carl J.; Daryabeigi, Kamran; Poteet, Carl C.

    1998-01-01

    Metallic thermal protection systems (TPS) are being developed to help meet the ambitious goals of future reusable launch vehicles. Recent metallic TPS development efforts at NASA Langley Research Center are described. Foil-gage metallic honeycomb coupons, representative of the outer surface of metallic TPS were subjected to low speed impact, hypervelocity impact, rain erosion, and subsequent arcjet exposure. TPS panels were subjected to thermal vacuum, acoustic, and hot gas flow testing. Results of the coupon and panel tests are presented. Experimental and analytical tools are being developed to characterize and improve internal insulations. Masses of metallic TPS and advanced ceramic tile and blanket TPS concepts are compared for a wide range of parameters.

  18. Rare Earth Metals: Resourcefulness and Recovery

    NASA Astrophysics Data System (ADS)

    Wang, Shijie

    2013-10-01

    When we appreciate the digital revolution carried over from the twentieth century with mobile communication and the Internet, and when we enjoy our high-tech lifestyle filled with iDevices, hybrid cars, wind turbines, and solar cells in this new century, we should also appreciate that all of these advanced products depend on rare earth metals to function. Although there are only 136,000 tons of annual worldwide demand, (Cho, Rare Earth Metals, Will We Have Enough?)1 rare earth metals are becoming such hot commodities on international markets, due to not only to their increasing uses, including in most critical military hardware, but also to Chinese growth, which accounts for 95% of global rare earth metal production. Hence, the 2013 technical calendar topic, planned by the TMS/Hydrometallurgy and Electrometallurgy Committee, is particularly relevant, with four articles (including this commentary) contributed to the JOM October Issue discussing rare earth metals' resourcefulness and recovery.

  19. Time reducing exposure containing 18 fluorine flourodeoxyglucose master vial dispensing in hot lab: Omega technique

    PubMed Central

    Rao, Vatturi Venkata Satya Prabhakar; Manthri, Ranadheer; Hemalatha, Pottumuthu; Kumar, Vuyyuru Navin; Azhar, Mohammad

    2016-01-01

    Hot lab dispensing of large doses of 18 fluorine fluorodeoxyglucose in master vials supplied from the cyclotrons requires high degrees of skill to handle high doses. Presently practiced conventional method of fractionating from the inverted tiltable vial pig mounted on a metal frame has its own limitations such as increasing isotope handling times and exposure to the technologist. Innovative technique devised markedly improves the fractionating efficiency along with speed, precision, and reduced dose exposure. PMID:27095872

  20. Powder processing of nitrides (excluding hot isostatic processing). (Latest citations from Engineered Materials abstracts). Published Search

    SciTech Connect

    1996-02-01

    The bibliography contains citations concerning the properties and processing of metal nitride ceramics and refractories. Citations consider compacting and sintering processes. Phase transformations, crystallization, and devitrification processes are considered. Aluminum nitride, boron nitride, silicon nitride, silicon oxynitride, and titanium nitride are among materials discussed. The use of hot isostatic pressing is considered in a separate bibliography. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  1. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing

    SciTech Connect

    Lundström, H.

    2015-08-15

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  2. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing.

    PubMed

    Lundström, H

    2015-08-01

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  3. Density matrix description of laser-induced hot electron mediated photodesorption of NO from Pt(111)

    NASA Astrophysics Data System (ADS)

    Saalfrank, Peter; Baer, Roi; Kosloff, Ronnie

    1994-12-01

    Based on the numerical solution of the Liouville-von Neumann equation for dissipative systems, the photodesorption dynamics of NO/Pt(111) are studied. Dissipative terms are used to describe the quenching of electronically excited states on the metal, electronic dephasing and the indirect (hot-electron mediated) excitation processes in the DIMET and DIET limits. Norm and energy flow, desorption probabilities and density time-of-flight spectra are computed.

  4. Disaggregating Hot Water Use and Predicting Hot Water Waste in Five Test Homes

    SciTech Connect

    Henderson, H.; Wade, J.

    2014-04-01

    While it is important to make the equipment (or 'plant') in a residential hot water system more efficient, the hot water distribution system also affects overall system performance and energy use. Energy wasted in heating water that is not used is estimated to be on the order of 10 to 30 percent of total domestic hot water (DHW) energy use. This field monitoring project installed temperature sensors on the distribution piping (on trunks and near fixtures) and programmed a data logger to collect data at 5 second intervals whenever there was a hot water draw. This data was used to assign hot water draws to specific end uses in the home as well as to determine the portion of each hot water that was deemed useful (i.e., above a temperature threshold at the fixture). Five houses near Syracuse NY were monitored. Overall, the procedures to assign water draws to each end use were able to successfully assign about 50% of the water draws, but these assigned draws accounted for about 95% of the total hot water use in each home. The amount of hot water deemed as useful ranged from low of 75% at one house to a high of 91% in another. At three of the houses, new water heaters and distribution improvements were implemented during the monitoring period and the impact of these improvements on hot water use and delivery efficiency were evaluated.

  5. Disaggregating Hot Water Use and Predicting Hot Water Waste in Five Test Homes

    SciTech Connect

    Henderson, Hugh; Wade, Jeremy

    2014-04-01

    While it is important to make the equipment (or "plant") in a residential hot water system more efficient, the hot water distribution system also affects overall system performance and energy use. Energy wasted in heating water that is not used is estimated to be on the order of 10%-30% of total domestic hot water (DHW) energy use. This field monitoring project installed temperature sensors on the distribution piping (on trunks and near fixtures) in five houses near Syracuse, NY, and programmed a data logger to collect data at 5 second intervals whenever there was a hot water draw. This data was used to assign hot water draws to specific end uses in the home as well as to determine the portion of each hot water that was deemed useful (i.e., above a temperature threshold at the fixture). Overall, the procedures to assign water draws to each end use were able to successfully assign about 50% of the water draws, but these assigned draws accounted for about 95% of the total hot water use in each home. The amount of hot water deemed as useful ranged from low of 75% at one house to a high of 91% in another. At three of the houses, new water heaters and distribution improvements were implemented during the monitoring period and the impact of these improvements on hot water use and delivery efficiency were evaluated.

  6. Fabrication and Preliminary Evaluation of Metal Matrix Microencapsulated Fuels

    SciTech Connect

    Terrani, Kurt A; Kiggans, Jim; Snead, Lance Lewis

    2012-01-01

    The metal matrix microencapsulated (M3) fuel concept for light water reactors (LWRs), consisting of coated fuel particles dispersed in a zirconium metal matrix, is introduced. Fabrication of M3 fuels by hot pressing, hot isostatic pressing, or extrusion methodologies has been demonstrated over the temperature range 800-1050 C. Various types of coated fuel particles with outermost layers of pyrocarbon, SiC, ZrC, and TiN have been incorporated into the zirconium metal matrix. Mechanical particle-particle and chemical particle-matrix interactions have been observed during the preliminary characterization of as-fabricated M3 specimens. Irradiation of three M3 rodlets with surrogate coated fuel particles was carried out at mean rod temperature of 400 C to 4.6 dpa in the zirconium metal matrix. Due to absence of texture in the metal matrix no irradiation growth strain (<0.09%) was detected during the post-irradiation examination.

  7. Powder processing of nitrides by hot isostatic pressing. (Latest citations from Engineered Materials abstracts). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the use of hot isostatic pressing to process metal nitrides. Citations discuss the fabrication of components for internal combustion, advanced heat, and gas turbine engines. Ceramic matrix composites are considered. (Contains a minimum of 77 citations and includes a subject term index and title list.)

  8. A DEEP X-RAY VIEW OF THE HOT HALO IN THE EDGE-ON SPIRAL GALAXY NGC 891

    SciTech Connect

    Hodges-Kluck, Edmund J.; Bregman, Joel N.

    2013-01-01

    NGC 891 is a nearby edge-on galaxy that is similar to the Milky Way and has a hot X-ray-emitting halo that could arise from accretion, a galactic fountain, or a combination of the two. The metallicity of the gas can help distinguish between these models, and here we report on results that use 138 ks of archival Chandra data and 92 ks of new XMM-Newton data to measure the temperature and metallicity of the hot halo of the galaxy. We find good fits for a thermal model with kT {approx} 0.2 keV and Z {approx} 0.1 Z {sub Sun }, and rule out solar metallicity to more than 99% confidence. This result suggests accretion from the intergalactic medium as the origin for the hot halo. However, it is also possible to fit a two-temperature thermal model with solar metallicity where kT {sub 1} {approx} 0.1 keV and kT {sub 2} {approx} 0.25 keV. A consideration of the cooling rate and scale height prefers the single-temperature model. We also find that the cooling rate in the hot gas cannot explain the massive H I halo in the steady state. In addition, a galactic fountain model cannot eject enough mass to account for the H I halo, and we speculate that the neutral halo may be gas from a prior outflow that has since cooled.

  9. Spectral analysis of hot helium-rich white dwarfs.

    NASA Astrophysics Data System (ADS)

    Dreizler, S.; Werner, K.

    1996-10-01

    We present a model atmosphere analysis of most known hot helium-rich white dwarfs of spectral type DO. The stars represent the non-DA white dwarf cooling sequence from the hot end (T_eff_=~120000K) down to the DB gap (T_eff_=~45000K). From medium resolution optical spectra, effective temperatures, surface gravities, and element abundances are determined by means of non-LTE model atmospheres. Compared to previous LTE analyses available for some of the program stars, higher effective temperatures are derived. The existence of the DB gap is confirmed. For the first time reliable surface gravities for a large sample of DO white dwarfs are determined. With the help of theoretical evolutionary tracks the DO masses are determined. We find a mean value of 0.59+/-0.08Msun_ which virtually coincides with the mean masses of the DA and DB white dwarfs. Hydrogen cannot be identified in any optical DO spectrum, which includes the former DOA prototype HZ21. Hence HD149499B remains the only DO white dwarf with a positive (FUV) detection of trace hydrogen in the photosphere. The number ratio of DA/non-DA white dwarfs significantly increases along the cooling sequence and thus corroborates the hydrogen float-up hypothesis as an explanation for the DB gap. From optical, IUE, and HST spectra metal abundances or upper limits could be derived for most DOs, allowing a comprehensive comparison with predictions from diffusion/radiative levitation calculations. A large scatter in metallicities is found, even among objects with similar parameters and no clear trend along the cooling sequence is detectable. This is severely at odds with theoretical predictions. The evolutionary link between DO white dwarfs, the PG1159 stars and DB white dwarfs is discussed, in particular considering the overlapping positions of DO and PG1159 stars in the HR diagram.

  10. The evolution of meteorites and planets from a hot nebula

    NASA Astrophysics Data System (ADS)

    Tarling, Donald H.

    2015-06-01

    Meteorites have a hot origin as planetary materials derive from a supernova, similar to SN1987A, and were acquired by a nearby nova, the Sun. The supernova plasmas became zoned around the nova, mainly by their electromagnetic properties. Carbon and carbide dusts condensed first, followed, within the Inner Planetary Zone, by Ca-Mg-Al oxides and then by iron and nickel metal droplets. In the inner Asteroid Belt, the metals aggregated into clumps as they solidified but over a much longer time in the Inner Zone. 'Soft' collisions formed larger (<∼20 km) objects in the Asteroid Belt; in the Inner Zone these aggregated forming proto-planetary cores during inwards orbital migration. In the Asteroid Belt, glassy olivines condensed, followed more open lattice minerals growing grew primarily by diffusion. Brittle silicate crystals were comminuted and only aggregated into the carbonaceous meteorites when water-ices formed. The inner planets differentiated by at least 4.4 Ga. Jupiter and the outer planets grew on asteroidal bodies thrown out into freezing water vapours and only formed by 4.1 Ga, resulting in the Late Heavy Bombardment, initially by meteoritic materials and later supplemented by ices from, and beyond, the Asteroid Belt. Critical factors are the properties of very high temperature supernova plasmas, the duration of the molten iron phase in the inner zone. Evidence usually quoted for a cold origin derives from late stage processes in hot meteorite evolution. While highly speculative, it is shown that meteorites and planets can be formed by known processes as supernova plasmas cool.

  11. Nanoscale Hot-Wire Probes for Boundary-Layer Flows

    NASA Technical Reports Server (NTRS)

    Tedjojuwono, Ken T.; Herring, Gregory C.

    2003-01-01

    Hot-wire probes having dimensions of the order of nanometers have been proposed for measuring temperatures (and possibly velocities) in boundary-layer flows at spatial resolutions much finer and distances from walls much smaller than have been possible heretofore. The achievable resolutions and minimum distances are expected to be of the order of tens of nanometers much less than a typical mean free path of a molecule and much less than the thickness of a typical flow boundary layer in air at standard temperature and pressure. An additional benefit of the small scale of these probes is that they would perturb the measured flows less than do larger probes. The hot-wire components of the probes would likely be made from semiconducting carbon nanotubes or ropes of such nanotubes. According to one design concept, a probe would comprise a single nanotube or rope of nanotubes laid out on the surface of an insulating substrate between two metallic wires. According to another design concept, a nanotube or rope of nanotubes would be electrically connected and held a short distance away from the substrate surface by stringing it between two metal electrodes. According to a third concept, a semiconducting nanotube or rope of nanotubes would be strung between the tips of two protruding electrodes made of fully conducting nanotubes or ropes of nanotubes. The figure depicts an array of such probes that could be used to gather data at several distances from a wall. It will be necessary to develop techniques for fabricating the probes. It will also be necessary to determine whether the probes will be strong enough to withstand the aerodynamic forces and impacts of micron-sized particles entrained in typical flows of interest.

  12. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    RICHARD A. WAGNER

    1998-09-04

    This report describes the fabrication and testing of continuous fiber ceramic composite (CFCC) based hot gas filters. The fabrication approach utilized a modified filament winding method that combined both continuous and chopped fibers into a novel microstructure. The work was divided into five primary tasks. In the first task, a preliminary set of compositions was fabricated in the form of open end tubes and characterized. The results of this task were used to identify the most promising compositions for sub-scale filter element fabrication and testing. In addition to laboratory measurements of permeability and strength, exposure testing in a coal combustion environment was performed to asses the thermo-chemical stability of the CFCC materials. Four candidate compositions were fabricated into sub-scale filter elements with integral flange and a closed end. Following the 250 hour exposure test in a circulating fluid bed combustor, the retained strength ranged from 70 t 145 percent of the as-fabricated strength. The post-test samples exhibited non-catastrophic failure behavior in contrast to the brittle failure exhibited by monolithic materials. Filter fabrication development continued in a filter improvement and cost reduction task that resulted in an improved fiber architecture, the production of a net shape flange, and an improved low cost bond. These modifications were incorporated into the process and used to fabricate 50 full-sized filter elements for testing in demonstration facilities in Karhula, Finland and at the Power Systems Development Facility (PSDF) in Wilsonville, AL. After 581 hours of testing in the Karhula facility, the elements retained approximately 87 percent of their as-fabricated strength. In addition, mechanical response testing at Virginia Tech provided a further demonstration of the high level of strain tolerance of the vacuum wound filter elements. Additional testing in the M. W. Kellogg unit at the PSDF has accumulated over 1800 hours of

  13. Structure and hot hardness of RuAl-based alloys produced by reactive sintering using hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Povarova, K. B.; Morozov, A. E.; Padalko, A. G.; Drozdov, A. A.

    2008-04-01

    The structure and hot hardness (at temperatures up to 1100°C) of RuAl-based powder alloys with 1 3 at % Ni, Mo, Re, or Ru are studied. The alloys are produced by the reactive sintering of cold-compacted bars and subsequent threefold isostatic pressing with intermediate annealing at 1500°C performed after the first hot isostatic pressing. The samples have a residual pore content of 1 2.5 vol % and are characterized by a micrononuniform distribution of base and alloying elements. The alloys with refractory metals, such as Re, Mo, or Ru, are found to have the maximum hardness at all temperatures under study. At low temperatures, the effect is more substantial; the hardness of the Re-containing alloys exceeds that of the other alloys by a factor of 1.3 3.6. The increase in the hardness related to solid-solution alloying becomes more substantial owing to the microinhomogeneity of the sintered powder alloys and weakens because of microporosity. Recommendations that allow the uniformity of the distribution of the base and alloying elements to be increased are given.

  14. 40 CFR 68.85 - Hot work permit.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Hot work permit. 68.85 Section 68.85... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.85 Hot work permit. (a) The owner or operator shall issue a hot work permit for hot work operations conducted on or near a covered process....

  15. 40 CFR 68.85 - Hot work permit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Hot work permit. 68.85 Section 68.85... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.85 Hot work permit. (a) The owner or operator shall issue a hot work permit for hot work operations conducted on or near a covered process....

  16. 40 CFR 68.85 - Hot work permit.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Hot work permit. 68.85 Section 68.85... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.85 Hot work permit. (a) The owner or operator shall issue a hot work permit for hot work operations conducted on or near a covered process....

  17. The Metallicity of Giant Planets

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel P.; Fortney, Jonathan

    2015-12-01

    Unique clues about the formation processes of giant planets can be found in their bulk compositions. Transiting planets provide us with bulk density determinations that can then be compared to models of planetary structure and evolution, to deduce planet bulk metallicities. At a given mass, denser planets have a higher mass fraction of metals. However, the unknown hot Jupiter "radius inflation" mechanism leads to under-dense planets that severely biases this work. Here we look at cooler transiting gas giants (Teff < 1000 K), which do not exhibit the radius inflation effect seen in their warmer cousins. We identified 40 such planets between 20 M_Earth and 20 M_Jup from the literature and used evolution models to determine their bulk heavy-element ("metal") mass. Several important trends are apparent. We see that all planets have at least ~10 M_Earth of metals, and that the mass of metal correlates strongly with the total mass of the planet. The heavy-element mass goes as the square root of the total mass. Both findings are consistent with the core accretion model. We also examined the effect of the parent star metallicity [Fe/H], finding that planets around high-metallicity stars are more likely to have large amounts of metal, but the relation appears weaker than previous studies with smaller sample sizes had suggested. We also looked for connections between bulk composition and planetary orbital parameters and stellar parameters, but saw no pattern, which is also an important result. This work can be directly compared to current and future outputs from planet formation models, including population synthesis.

  18. Experiments with the hot list strategy

    SciTech Connect

    Wos, L.

    1997-10-01

    Experimentation strongly suggests that, for attacking deep questions and hard problems with the assistance of an automated reasoning program, the more effective paradigms rely on the retention of deduced information. A significant obstacle ordinarily presented by such a paradigm is the deduction and retention of one or more needed conclusions whose complexity sharply delays their consideration. To mitigate the severity of the cited obstacle, the author formulates and features in this report the hot list strategy. The hot list strategy asks the researcher to choose, usually from among the input statements, one or more clauses that are conjectured to play a key role for assignment completion. The chosen clauses - conjectured to merit revisiting, again and again - are placed in an input list of clauses, called the hot list. When an automated reasoning program has decided to retain a new conclusion C - before any other clause is chosen to initiate conclusion drawing - the presence of a nonempty hot list (with an appropriate assignment of the input parameter known as heat) causes each inference rule in use to be applied to C together with the appropriate number of members of the hot list. Members of the hot list are used to complete applications of inference rules and not to initiate applications. The use of the hot list strategy thus enables an automated reasoning program to briefly consider a newly retained conclusion whose complexity would otherwise prevent its use for perhaps many CPU-hours. To give evidence of the value of the strategy, the author focuses on four contexts: (1) dramatically reducing the CPU time required to reach a desired goal; (2) finding a proof of a theorem that had previously resisted all but the more inventive automated attempts; (3) discovering a proof that is more elegant than previously known; and (4) answering a question that had steadfastly eluded researchers relying on an automated reasoning program.

  19. Ultraprecision microelectroforming of metals and metal alloys

    NASA Astrophysics Data System (ADS)

    Loewe, Holger; Ehrfeld, Wolfgang; Diebel, Joerg

    1997-09-01

    In recent years, microsystem technology and its growing importance for actuators, sensors, optics and microfluidics, only to name a few, have gained a lot of attention. Specific applications demand fabrication techniques allowing a fast and reliable replication of microstructure products in a variety of materials. An important technique for replication processes of microstructures in many applications of microsystem technology are microelectroforming processes, generating a variety of metals and metal alloys with tailored characteristics. Here, new results in the development of alloys for specific applications as well as their applications are reported: (1) Newly developed alloys: Nickel-iron alloys enable the production of soft magnetic microstructures e.g. for specific applications in microactuators. Nickel-cobalt and Nickel-tungsten alloys have been employed for the manufacture of microstructured tools with excellent mechanical properties regarding wear and mechanical durability. These tools have been applied to hot-embossing and injection molding processes successfully. (2) Microelectroforming within the frame of the LIGA technique allows the manufacturing of extremely precise electrodes with various cross-sections and heights for (mu) - electro discharge machining. The combination of these techniques enables the production of microstructures from non- electrodepositable materials, like stainless steel e.g. for large scale replication processes. (3) The precision of microelectroforming enables the replication of structured surfaces on a nanoscale for molecular microelectronics or special applications. The new types of alloys reported here significantly enlarge the applicability of microelectroforming processes for tool fabrication or direct use. Moreover combining this process with other microstructuring processes like injection molding or (mu) -EDM techniques generates a powerful tool for microsystem technology.

  20. 10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY... Water Heaters, Hot Water Supply Boilers and Unfired Hot Water Storage Tanks § 431.102...

  1. Decontamination of Hot Cells and Hot Pipe Tunnel at NASA's Plum Brook Reactor Facility

    SciTech Connect

    Anderson, M.G.; Halishak, W.F.

    2008-07-01

    The large scale decontamination of the concrete Hot Cells and Hot Pipe Tunnel at NASA's Plum Brook Reactor Facility demonstrates that novel management and innovative methods are crucial to ensuring that the successful remediation of the most contaminated facilities can be achieved with minimal risk to the project stakeholders. (authors)

  2. HOT CELL BUILDING, TRA632. HOT CELL AWAITS INSTALLATION OF SHIELDED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HOT CELL BUILDING, TRA-632. HOT CELL AWAITS INSTALLATION OF SHIELDED WINDOWS. OVERHEAD MASTER/SLAVE MANIPULATORS (LEFT, ABOVE WORKING WINDOWS) WILL MOVE ACROSS GUIDE RAILS IN SLOT ABOVE THE WINDOWS. CAMERA FACING SOUTHEAST. INL NEGATIVE NO. 8996. Unknown Photographer, 10/28/1953 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  3. A&M. Hot cell annex (TAN633) interior under construction. Hot cells ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    A&M. Hot cell annex (TAN-633) interior under construction. Hot cells and their doors are along concrete wall. Note side wall of pumice block. Photographer: Jack L. Anderson. Date: October 28, 1957. INEEL negative no. 57-5335 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  4. Ethylene irradiation: a new route to grow graphene on low reactivity metals.

    PubMed

    Martínez-Galera, Antonio J; Brihuega, Iván; Gómez-Rodríguez, José M

    2011-09-14

    A novel technique for growing graphene on relatively inert metals, consisting in the thermal decomposition of low energy ethylene ions irradiated on hot metal surfaces in ultrahigh vacuum, is reported. By this route, we have grown graphene monolayers on Cu(111) and, for the first time, on Au(111) surfaces. For both noble metal substrates, but particularly for Au(111), our scanning tunneling microscopy and spectroscopy measurements provide sound evidence of a very weak graphene-metal interaction.

  5. Metal oxide films on metal

    DOEpatents

    Wu, Xin D.; Tiwari, Prabhat

    1995-01-01

    A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

  6. Chemical processes involved in the initiation of hot corrosion of B-1900 and NASA-TRW VIA. [high temperature tests of superalloys

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1979-01-01

    Sodium surface-induced hot corrosion of B-1900 and NASA-TRW VIA alloys at 900 C has been studied, with special attention to the chemical reactions during and immediately after the induction period. Thermogravimetric tests were run and data were obtained by chemical analysis of water soluble metal salts and of residual sulfate. Surface analyses of hot corroded samples were obtained by spectroscopic techniques (ESCA). A chemical mechanism for elucidating Na2SO4-induced hot corrosion is proposed indicating that hot corrosion is initiated by basic fluxing of the protective Al2O3 scale. The sequential, catastrophic corrosion results from molybdenum content. The self-sustaining feature is a consequence of the cyclic nature of the acidic fluxing. It is believed that the mechanism is applicable not only to laboratory results, but also to the practical problem of hot corrosion encountered in gas turbine engines.

  7. Formation and Stability of "Hot Earth" Planets

    NASA Astrophysics Data System (ADS)

    Raymond, Sean

    2007-05-01

    Close-in planets with masses less than one Neptune mass have been detected around roughly ten stars to date. In addition to these so-called "Hot Neptunes" or "Hot Super-Earths", upcoming missions such as CoRot and Kepler expect to find a large number of smaller, close-in "Hot Earths". Most disk models do not contain a large amount of mass in their innermost regions. So, how do Hot Earths form? There are several candidate mechanisms: 1) A "type 2" migrating giant planet can shepherd material interior to strong mean motion resonances. More than half of the solid component of the disk inside the giant planet's starting orbit can be displaced to the region interior to the giant planet's final orbit. So, many close-in giant planets may be accompanied by "hot Earths"; 2) Terrestrial cores, interacting tidally with the gaseous disk, can "type 1" migrate into the very inner disk. Interactions between cores may result in near-resonant configurations; and 3) In a system with two or more giant planets with non-zero eccentricities, dispersal of the gaseous disk can cause secular resonances to sweep through the system, and can moderately enhance the amount of material in the inner regions. Each of these mechanisms makes predictions that should be testable in the near future. References: Fogg & Nelson (2005, 2007), Zhou et al (2005), Raymond, Mandell & Sigurdsson (2006), Mandell, Raymond & Sigurdsson (2007), Terquem & Papaloizou (2007)

  8. Metamaterial perfect absorber based hot electron photodetection.

    PubMed

    Li, Wei; Valentine, Jason

    2014-06-11

    While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991

  9. Metal Coatings

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During the Apollo Program, General Magnaplate Corporation developed process techniques for bonding dry lubricant coatings to space metals. The coatings were not susceptible to outgassing and offered enhanced surface hardness and superior resistance to corrosion and wear. This development was necessary because conventional lubrication processes were inadequate for lightweight materials used in Apollo components. General Magnaplate built on the original technology and became a leader in development of high performance metallurgical surface enhancement coatings - "synergistic" coatings, - which are used in applications from pizza making to laser manufacture. Each of the coatings is designed to protect a specific metal or group of metals to solve problems encountered under operating conditions.

  10. Tests of fixity of the Indo-Atlantic hot spots relative to Pacific hot spots

    NASA Astrophysics Data System (ADS)

    Koivisto, Emilia A.; Andrews, David L.; Gordon, Richard G.

    2014-01-01

    Rates of inter-hot spot motion have been debated for decades. Herein we present updated predictions for the tracks of the Tristan da Cunha, Réunion, and Iceland hot spots assuming them to be fixed relative to Pacific hot spots. Uncertainties in Pacific hot spot rotations, which include uncertainties in the current locations of hot spots of 100-200 km, are combined with uncertainties in relative plate motions accumulated through the plate circuit to obtain the final uncertainty in the predicted positions (including uncertainties of 150-200 km in the current locations of the Indo-Atlantic hot spots). Improvements to reconstruction methods, to relative plate reconstructions, to age dates along the tracks, and to the geomagnetic reversal timescale lead to significant changes from prior results. When compared with the observed tracks, the predicted tracks indicate nominal rates of motion of only 2-6 mm a-1 of these Indo-Atlantic hot spots relative to Pacific hot spots over the past 48 Ma. Within the uncertainties, the rates range from no motion to rates as high as 8-13 mm a-1. For reconstructions prior to 48 Ma B.P., however, the apparent rates of inter-hot spot motion are much larger, 46-55 ± 20 mm a-1, if the motion occurred entirely between 68 Ma B.P. and 48 Ma B.P. Either hot spots moved rapidly before 48 Ma B.P., and slowed drastically at ≈ 48 Ma B.P., or global plate circuits through Antarctica become less reliable as one goes increasingly further into the past. Most paleomagnetic data favor the latter explanation.

  11. Hot corrosion behavior of platinum-modified nickel- and cobalt-based alloys and coatings

    NASA Astrophysics Data System (ADS)

    Deodeshmukh, Vinay Prakash

    High temperature degradation by hot corrosion (650-1000°C) and/or oxidation (>1000°C) can severely reduce the longevity of advanced gas turbine engine components. The protection of high-temperature components against hot corrosion or oxidation is typically conferred by the application of either a diffusion or overlay metallic coating that is able to form a continuous, adherent, and slow-growing oxide scale. There are currently no coatings that provide adequate protection to both hot corrosion and oxidation. Indeed, there is a particular need for such protective coatings because many advanced aero, marine, and industrial gas-turbines operate in both hot corrosion and oxidation regimes in their duty cycle. Recent work at Iowa State University (ISU) has showed that a wide range Pt+Hf-modified gamma'-Ni3Al + gamma-Ni alloy compositions form a very adherent and slow-growing Al 2O3 scale. In fact, the results reported suggest that Pt+Hf-modified gamma' + gamma coatings offer a viable superior alternative to beta-NiAl(Pt)-based coatings. The main thrust of this study was to assess and establish optimum target gamma' + gamma coating compositions for extending the service life of high-temperature gas turbine components exposed to hot corrosion and oxidation conditions. Both high temperature hot-corrosion (HTHC-900°C) and low temperature hot-corrosion (LTHC-705°C) behaviors of the Pt+Hf-modified gamma' + gamma alloys were assessed. The salt used to bring about hot corrosion was Na 2SO4. Quite interestingly, it was found that the HTHC resistance of gamma' + gamma alloys improved with up to about 10 at.% Pt addition, but then decreased significantly with increasing Pt content up to 30 at.% (the maximum level studied); however, under LTHC conditions the resistance of gamma' + gamma alloys improved with increasing Pt content up to 30 at.%. To further improve hot corrosion resistance of Pt+Hf-modified gamma' + gamma alloys, the effects of systematic additions of Cr, Si, and

  12. Estimating mixing in hot Jupiter atmospheres

    NASA Astrophysics Data System (ADS)

    Kataria, Tiffany; Lewis, Nikole; Lian, Yuan; Marley, Mark S.

    2016-10-01

    Ground- and space-based observations of exoplanets have shown that like solar system planets and brown dwarfs, clouds are ubiquitous in exoplanet atmospheres. However, the dynamics that underpin their formation and transport are still poorly understood. In order to further elucidate the three-dimensional mixing in exoplanet atmospheres, we present a generalized study comparing the dynamics of exoplanets to brown dwarfs and solar system planets. We utilize previously published hot Jupiter GCMs to estimate the microphysical timescales that dictate cloud formation and calculate horizontal and vertical wind profiles, and compare those to these other classes of substellar objects. In doing so, we can provide a framework for which to explain the small cloud particle sizes observed in hot Jupiters, and create a generalized profile for vertical mixing in hot Jupiter atmospheres.

  13. Chandra Galaxy Atals - Global Hot Gas Properties

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Woo; Anderson, Craig; Burke, Douglas J.; Fabbiano, Giuseppina; Fruscione, Antonella; Lauer, Jennifer L.; McCollough, Michael L.; Morgan, Douglas; Mossman, Amy; O'Sullivan, Ewan; Paggi, Alessandro; Trinchieri, Ginevra

    2016-04-01

    The hot gas in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. As the hot gas is often extended to the outskirts beyond the optical size, the large scale structural features identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion/stripping and star formation and its quenching. In our new project, the Chandra Galaxy Atlas, we systematically analyze the archival Chandra data of ~100 ETGs to study the hot ISM. Using uniformly derived data products with spatially resolved spectral information, we will present gas morphology, scaling relations and X-ray based mass profiles and address their implications.

  14. Seeded hot dark matter models with inflation

    NASA Technical Reports Server (NTRS)

    Gratsias, John; Scherrer, Robert J.; Steigman, Gary; Villumsen, Jens V.

    1993-01-01

    We examine massive neutrino (hot dark matter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot dark matter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold dark matter models.

  15. Cool and hot flux ropes, their helicity

    NASA Astrophysics Data System (ADS)

    Nindos, Alexander

    2016-07-01

    We will review recent indirect and direct evidence for the existence of magnetic flux ropes in the solar atmosphere. Magnetic flux ropes may appear as S-shaped or reverse S-shaped (sigmoidal) structures in regions that are likely to erupt, and may also show in nonlinear force-free field extrapolations that use data from photospheric vector magnetograms as boundary condition. The availability of high sensitivity data recorded with unprecedented spatial and temporal resolution in hot EUV wavelengths by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) has revealed the existence of coherent structures identified as hot flux ropes. In this presentation, we will review the properties of both cool and hot flux ropes with an emphasis on the frequency of their occurrence in large flares and on their magnetic helicity content.

  16. Multi-cylinder hot gas engine

    DOEpatents

    Corey, John A.

    1985-01-01

    A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

  17. Hot gas filter and system assembly

    DOEpatents

    Lippert, Thomas Edwin; Palmer, Kathryn Miles; Bruck, Gerald Joseph; Alvin, Mary Anne; Smeltzer, Eugene E.; Bachovchin, Dennis Michael

    1999-01-01

    A filter element for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system.

  18. Hot gas filter and system assembly

    DOEpatents

    Lippert, T.E.; Palmer, K.M.; Bruck, G.J.; Alvin, M.A.; Smeltzer, E.E.; Bachovchin, D.M.

    1999-08-31

    A filter element is described for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system. 8 figs.

  19. Radioactive hot cell access hole decontamination machine

    DOEpatents

    Simpson, William E.

    1982-01-01

    Radioactive hot cell access hole decontamination machine. A mobile housing has an opening large enough to encircle the access hole and has a shielding door, with a door opening and closing mechanism, for uncovering and covering the opening. The housing contains a shaft which has an apparatus for rotating the shaft and a device for independently translating the shaft from the housing through the opening and access hole into the hot cell chamber. A properly sized cylindrical pig containing wire brushes and cloth or other disks, with an arrangement for releasably attaching it to the end of the shaft, circumferentially cleans the access hole wall of radioactive contamination and thereafter detaches from the shaft to fall into the hot cell chamber.

  20. Kepler constraints on planets near hot Jupiters

    SciTech Connect

    Steffen, Jason H.; Ragozzine, Darin; Fabrycky, Daniel C.; Carter, Joshua A.; Ford, Eric B.; Holman, Matthew J.; Rowe, Jason F.; Welsh, William F.; Borucki, William J.; Boss, Alan P.; Ciardi, David R.; /Caltech /Harvard-Smithsonian Ctr. Astrophys.

    2012-05-01

    We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2:1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.