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Sample records for ni taisuru hot

  1. Microstructure, Phase Transformations, and Properties of Hot-Extruded Ni-Rich NiTi Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Lekston, Z.; Zubko, M.; Prusik, K.; Stróż, D.

    2014-07-01

    Processing of NiTi shape memory alloys strongly influences their microstructure, phase transformations, mechanical, and shape memory properties. Hot forging, hot swaging, or hot rolling are efficient techniques for obtaining the desired shape, but during multiple operations the material must be heated and worked in the temperature range from 700 to 900 °C. During these processes, intense oxidation takes place. In order to reduce it, the hot-pack working is applied. The hot extrusion is more effective for reduction of ingot, billet, and rod diameters than hot forging, hot swaging, or hot rolling. Also, during hot extrusion the material surface undergoes considerably less oxidation. In the present work, results of the characterization by differential scanning calorimetry, low-temperature x-ray powder diffraction, and three-point bending and free recovery ASTM F2082-06 tests of the samples after hot direct extrusion and heat treatment are presented. The obtained alloy after hot direct extrusion exhibits desired shape memory effect. The phase transformations during cooling and heating cycle occur with the presence of the R phase. The range of the characteristic temperatures for the obtained material gives possibility for further medical applications. After annealing at 400 and 500 °C, the characteristic temperatures shift to higher values.

  2. Burner rig hot corrosion of a single crystal Ni-48Al-Ti-Hf-Ga alloy

    SciTech Connect

    Nesbitt, J.A.; Darolia, R.; Cuy, M.D.

    1999-07-01

    The hot corrosion resistance of a single crystal Ni-48Al-1Ti-0.5Hf-0.2Ga alloy was examined in a Mach 0.3 burner rig at 900 C for 300 hours. The combustion chamber was doped with 2 ppmw synthetic sea salt. The hot corrosion attack produced a random mound morphology on the surface. Microstructurally, the hot corrosion attack appeared to initiate with oxide-filled pits which were often broad and shallow. At an intermediate stage, the pits increased in size to incorporate unoxidized Ni islands in the corrosion product. The rampant attack stage, which was observed only at sharp sample corners, was characterized by rapid inward growth of alumina in finger-like protrusions incorporating significant amounts of Al-depleted Ni islands. Aluminum consumption in the oxide fingers resulted in the growth of a {gamma}{prime} layer ahead of the advancing oxide fingers.

  3. Burner Rig Hot Corrosion of a Single Crystal Ni-48Al-Ti-Hf-Ga Alloy

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.; Darolia, Ram; Cuy, Michael D.

    1998-01-01

    The hot corrosion resistance of a single crystal Ni-48Al-1Ti-0.5Hf-0.2Ga alloy was examined in a Mach 0.3 burner rig at 900 C for 300 hours. The combustion chamber was doped with 2 ppmw synthetic sea salt. The hot corrosion attack produced a random mound morphology on the surface. Microstructurally, the hot corrosion attack appeared to initiate with oxide-filled pits which were often broad and shallow. At an intermediate stage, the pits increased in size to incorporate unoxidized Ni islands in the corrosion product. The rampant attack stage, which was observed only at sharp sample corners, was characterized by rapid inward growth of alumina in finger-like protrusions incorporating significant amounts of Al-depleted Ni islands. Aluminum consumption in the oxide fingers resulted in the growth of a gamma' layer ahead of the advancing oxide fingers.

  4. Hot corrosion testing of Ni-based alloys and coatings in a modified Dean rig

    NASA Astrophysics Data System (ADS)

    Steward, Jason Reid

    Gas turbine blades are designed to withstand a variety of harsh operating conditions. Although material and coating improvements are constantly administered to increase the mean time before turbine refurbishment or replacement, hot corrosion is still considered as the major life-limiting factor in many industrial and marine gas turbines. A modified Dean rig was designed and manufactured at Tennessee Technological University to simulate the accelerated hot corrosion conditions and to conduct screening tests on the new coatings on Ni-based superalloys. Uncoated Ni-based superalloys, Rene 142 and Rene 80, were tested in the modified Dean rig to establish a testing procedure for Type I hot corrosion. The influence of surface treatments on the hot corrosion resistance was then investigated. It was found that grit-blasted specimens showed inferior hot corrosion resistance than that of the polished counterpart. The Dean rig was also used to test model MCrAlY alloys, pack cementation NiAl coatings, and electro-codeposited MCrAlY coatings. Furthermore, the hot corrosion attack on the coated-specimens were also assessed using a statistical analysis approach.

  5. Single-Crystal NiAl-X Alloys Tested for Hot Corrosion

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    1999-01-01

    Single-crystal nickel aluminide (NiAl) has been investigated extensively throughout the last several years as a potential structural material in aero-gas turbine engines. The attractive features of NiAl in comparison to Ni-base superalloys include a higher melting point, lower density, higher thermal conductivity, and excellent oxidation resistance. However, NiAl suffers from a lack of ductility and fracture toughness at low temperatures and a low creep strength at high temperatures. Alloying additions of hafnium (Hf), gallium (Ga), titanium (Ti), and chromium (Cr) have each shown some benefit to the mechanical properties over that of the binary alloy. However, the collective effect of these alloying additions on the environmental resistance of NiAl-X was unclear. Hence, the present study was undertaken to examine the hot corrosion behavior of these alloys. A companion study examined the cyclic oxidation resistance of these alloys. Several single-crystal NiAl-X alloys (where X is Hf, Ti, Cr, or Ga) underwent hot corrosion testing in a Mach 0.3 burner rig at the NASA Lewis Research Center. Samples were tested for up to 300 1-hr cycles at a temperature of 900 C. It was found that increasing the Ti content from 1 to 5 at.% degraded the hot corrosion behavior. This decline in the behavior was reflected in high weight gains and large corrosion mound formation during testing (see the figures). However, the addition of 1 to 2 at.% Cr to alloys containing 4 to 5 at.% Ti appeared to greatly reduce the susceptibility of these alloys to hot corrosion attack and negated the deleterious effect of the increased Ti addition.

  6. The characteristics of hot swaged NiAl intermetallic compounds with ternary additions consolidated by HIP techniques

    SciTech Connect

    Ishiyama, S.; Eto, M.; Mishima, Y.; Miura, S.; Suzuki, T.

    1995-12-31

    Stoichiometric and non-stoichiometric NiAl intermetallics with ternary additives, such as Ti, Zr, Hf, V, Nb, Ta, Cr, Mo or Mo/e, W, Mn, Fe, Cu and B, fabricated with the combination of Hot Isostatic Pressing (HIP) and hot swaging techniques have been investigated. The mechanical properties of hot swaged NiAl with various ternary additives, consolidated by ion beam casting or HIP techniques, have been tested at temperatures ranging from R.T. to 1,000 C. It is found that significant tensile elongation at room temperature can be achieved by hot swaged as-HIP`ed NiAl compounds with Mo or Mo/Re additives, whereas cast and hot swaged compounds with Mo addition resulted in some elongation above 400 C.

  7. Characterization and Evaluation of Cyclic Hot Corrosion Resistance of Detonation-Gun Sprayed Ni-5Al Coatings on Inconel-718

    NASA Astrophysics Data System (ADS)

    Saladi, Sekar; Menghani, Jyoti V.; Prakash, Satya

    2015-06-01

    The high temperature hot corrosion behavior of bare and detonation-gun-sprayed Ni-5Al coatings on Ni-based superalloy Inconel-718 is comparatively discussed in the present study. Hot corrosion studies were carried out at 900 °C for 100 cycles in Na2SO4-60% V2O5 molten salt environment under cyclic heating and cooling conditions. The thermo-gravimetric technique was used to establish the kinetics of hot corrosion. X-ray diffraction, SEM/EDAX, and X-ray mapping techniques were used to analyze the hot corrosion products of bare and coated superalloys. The results indicate that Ni-5Al-coated superalloy showed very good hot corrosion resistance. The overall weight gain and parabolic rate constant of Ni-5Al-coated superalloy were less in comparison with the bare superalloy. The D-gun-sprayed Ni-5Al coating was found to be uniform, adherent, and dense in hot corrosion environment. The formation of nickel- and aluminum-rich oxide scale might have contributed for the better hot corrosion resistance of the coated superalloy.

  8. Hot Corrosion of Single-Crystal NiAl-X Alloys

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    1998-01-01

    Several single-crystal NiAl-X alloys (X=Hf, Ti, Cr, Ga) underwent hot corrosion testing in a Mach 0.3 burner rig at 900 deg. C for 300 1-hr cycles. The surface morphology after testing consisted of either mounds or an inward, uniform-type of attack which preserved surface features. It was observed that the surface morphology was affected by the surface preparation treatments. Microstructurally, the hot corrosion attack initiated as pits but evolved to a rampant attack consisting of the rapid inward growth of Al2O3. Electropolishing and chemical milling produced many pits and grooves on the surface. However, the presence of pits and grooves did not appear to strongly influence the hot corrosion response. Attack on many samples was strongly localized which was attributed to compositional inhomogeneity within the samples. It was found that increasing the Ti content from 1% to 5 % degraded the hot corrosion response of these alloys. In contrast, the addition of 1-2% Cr reduced the susceptibility of these alloys to hot corrosion attack and negated the deleterious effect of the 4-5% Ti addition.

  9. Burner Rig Hot Corrosion of Five Ni-Base Alloys Including Mar-M247

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.; Helmink, R.; Harris, K.; Erickson, G.

    2000-01-01

    The hot corrosion resistance of four new Ni-base superalloys was compared to that of Mar-M247 by testing in a Mach 0.3 burner rig at 900 C for 300 1-hr cycles. While the Al content was held the same as in the Mar-M247, the Cr and Co levels in the four new alloys were decreased while other strengthening elements (Re, Ta) were increased. Surprisingly, despite their lower Cr and Co contents, the hot corrosion behavior of all four new alloys was superior to that of the Mar-M247 alloy. The Mar-M247 alloy began to lose weight almost immediately whereas the other four alloys appeared to undergo an incubation period of 50-150 1-hr cycles. Examination of the cross-sectional microstructures showed regions of rampant corrosion attack (propagation stage) in all five alloys after 300 1-hr cycles . This rampant corrosion morphology was similar for each of the alloys with Ni and Cr sulfides located in an inner subscale region. The morphology of the attack suggests a classic "Type I", or high temperature, hot corrosion attack.

  10. Hot DA white dwarf model atmosphere calculations: including improved Ni PI cross-sections

    NASA Astrophysics Data System (ADS)

    Preval, S. P.; Barstow, M. A.; Badnell, N. R.; Hubeny, I.; Holberg, J. B.

    2017-02-01

    To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages need to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni IV-VI bound-bound and bound-free atomic data on model atmosphere calculations. Models including photoionization cross-section (PICS) calculated with AUTOSTRUCTURE show significant flux attenuation of up to ˜80 per cent shortward of 180 Å in the extreme ultraviolet (EUV) region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of these atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including AUTOSTRUCTURE PICS were found to change the abundances of N and O by as much as ˜22 per cent compared to models using hydrogenic PICS, but heavier species were relatively unaffected. Models including AUTOSTRUCTURE PICS caused the abundances of N/O IV and V to diverge. This is because the increased opacity in the AUTOSTRUCTURE PICS model causes these charge states to form higher in the atmosphere, more so for N/O V. Models using an extended line list caused significant changes to the Ni IV-V abundances. While both PICS and an extended line list cause changes in both synthetic spectra and measured abundances, the biggest changes are caused by using AUTOSTRUCTURE PICS for Ni.

  11. Microstructural Stability and Hot Deformation of γ- γ'- δ Ni-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Detrois, Martin; Helmink, Randolph C.; Tin, Sammy

    2014-11-01

    Nickel-base superalloys exhibit excellent high-temperature mechanical and physical properties and remain the first choice for structural components in advanced gas turbine engines for the aerospace propulsion and power generation applications. In response to the increasing demand for more efficient solutions and tighter requirements linked to gas turbine technologies, the properties of nickel-base superalloys can be improved by modification of their thermo-mechanical and/or compositional attributes. Recent investigations have revealed the potential use of ternary eutectic γ- γ'- δ Ni-base superalloys in advanced gas turbines due to high temperature mechanical properties that are comparable to state-of-the-art polycrystalline Ni-base superalloys. With properties largely dependent on microstructural strengthening mechanisms, both the composition and thermo-mechanical processing parameters of this novel class of alloys need to be optimized concurrently. The hot deformation characteristics of four γ- γ'- δ Ni-base superalloys with varying levels of Nb were evaluated at temperatures and strain rates between 1353 K and 1433 K (1080 °C and 1160 °C) and 0.01 to 0.001/s, respectively. Evidence of dislocation-based plasticity was observed following deformation at low temperatures and high strain rates, while high temperatures and low strain rates promoted superplasticity in these alloys. The extent of the microstructural changes and the magnitude of the cavitation damage which occurred during deformation was found to vary as a function of the alloy composition.

  12. Hot Deformation Characteristics of 13Cr-4Ni Stainless Steel Using Constitutive Equation and Processing Map

    NASA Astrophysics Data System (ADS)

    Kishor, Brij; Chaudhari, G. P.; Nath, S. K.

    2016-07-01

    Hot compression tests were performed to study the hot deformation characteristics of 13Cr-4Ni stainless steel. The tests were performed in the strain rate range of 0.001-10 s-1 and temperature range of 900-1100 °C using Gleeble® 3800 simulator. A constitutive equation of Arrhenius type was established based on the experimental data to calculate the different material constants, and average value of apparent activation energy was found to be 444 kJ/mol. Zener-Hollomon parameter, Z, was estimated in order to characterize the flow stress behavior. Power dissipation and instability maps developed on the basis of dynamic materials model for true strain of 0.5 show optimum hot working conditions corresponding to peak efficiency range of about 28-32%. These lie in the temperature range of 950-1025 °C and corresponding strain rate range of 0.001-0.01 s-1 and in the temperature range of 1050-1100 °C and corresponding strain rate range of 0.01-0.1 s-1. The flow characteristics in these conditions show dynamic recrystallization behavior. The microstructures are correlated to the different stability domains indicated in the processing map.

  13. Hot-injection synthesis of Ni-ZnO hybrid nanocrystals with tunable magnetic properties and enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Zeng, Deqian; Qiu, Yulong; Chen, Yuanzhi; Zhang, Qinfu; Liu, Xiang; Peng, Dong-Liang

    2017-04-01

    Magnetic metal-semiconductor hybrid nanocrystals containing ferromagnetic Ni and semiconductor ZnO have been prepared via a hot-injection route. The Ni-ZnO hybrid nanocrystals have a flower-like morphology that consists of Ni inner cores and ZnO petal shells. In spite of their large lattice mismatch, ZnO nanocrystals can still grow on faceted Ni nanocrystals to form stable interfaces. The composition of Ni-ZnO hybrid nanocrystals is readily controlled, and the average size of Ni core is tunable from 25 to 50 nm. Room temperature ferromagnetic properties are observed in these hybrid nanocrystals, and tunable magnetic properties also can be achieved by varying the size of Ni core. The as-prepared Ni-ZnO hybrid nanocrystals exhibit enhanced photocatalytic performance under ultraviolet light illumination as compared to pure ZnO nanocrystals. Furthermore, the superior reusability of hybrid nanocrystals for photocatalytic application is achieved by virtue of their magnetic properties. The facile and efficient seed-mediate strategy is particularly attractive to construct hybrid magnetic-semiconducting heterostructures. The as-obtained Ni-ZnO hybrid nanocrystals offer great potential for various applications due to their combined magnetic and semiconducting properties and low-cost earth-abundant availability.

  14. Hot Deformation Processing Map and Microstructural Evaluation of the Ni-Based Superalloy IN-738LC

    NASA Astrophysics Data System (ADS)

    Sajjadi, S. A.; Chaichi, A.; Ezatpour, H. R.; Maghsoudlou, A.; Kalaie, M. A.

    2016-04-01

    Hot deformation behavior of the Ni-based superalloy IN-738LC was investigated by means of hot compression tests over the temperature range of 1000-1200 °C and strain rate range of 0.01-1 s-1. The obtained peak flow stresses were related to strain rate and temperature through the hyperbolic sine equation with activation energy of 950 kJ/mol. Dynamic material model was used to obtain the processing map of IN-738LC. Analysis of the microstructure was carried out in order to study each domain's characteristic represented by the processing map. The results showed that dynamic recrystallization occurs in the temperature range of 1150-1200 °C and strain rate of 0.1 s-1 with the maximum power dissipation efficiency of 35%. The unstable domain was exhibited in the temperature range of 1000-1200 °C and strain rate of 1 s-1 on the occurrence of severe deformation bands and grain boundary cracking.

  15. Dynamic Recrystallization Behavior and Texture Evolution of NiAl Intermetallic During Hot Deformation

    NASA Astrophysics Data System (ADS)

    Huang, Zhenhan; Lu, Zhen; Jiang, Shaosong; Wang, Chongyang; Zhang, Kaifeng

    2017-05-01

    B2-ordered intermetallic NiAl was fabricated by hot pressing sintering and studied in terms of dynamic recrystallization behavior and texture evolution during isothermal compression over a temperature range of 1100-1300 °C and strain rate of 10-2 s-1 as well as strain rate of 10-3 to 10-1 s-1 and temperature of 1250 °C. It is found that DDRX mechanism operates predominantly at a high temperature and medium strain rate, while CDRX process is enhanced in the deformation condition of medium temperature and high strain rate yet in a localized way. In particular, progressive subgrain rotation takes place at 1250 °C/10-1 s-1. Conversely, dynamic recrystallization process is insufficient in the case of 1250 °C/10-3 s-1 and 1100 °C/10-2 s-1. Original hot pressing sintered billets are microstructurally homogeneous. Orientation distribution function sections reveal that the strong {110}<111> and {112}<111> texture components appear after deformation. Furthermore, the textures are strengthened with increasing temperature and strain rate.

  16. Hot corrosion of four superalloys - HA-188, S-57, IN-617, and TD-NiCrAl

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.

    1979-01-01

    Cyclic oxidation and hot corrosion tests of two cobalt-base and two nickel-base alloys are reported. The alloys were exposed to maximum temperatures of 900 and 1000 C in a Mach 0.3 burner rig whose flame was doped with various concentrations of sea salt and sodium sulfate for hot corrosion tests. The test data were subjected to a regression analysis for the development of model equations relating corrosion to temperature and for the effects of salt concentration and composition on corrosion. The corrosion resistance varied with temperature, sea salt concentration, and salt composition, concluding that the S-57 cobalt-base alloy was the most hot corrosion-resistant alloy, and the TD-NiCrAl nickel-base alloy was the least resistant. However, under straight oxidation conditions, the TD-NiCrAl was most resistant, while S-57 was the least resistant alloy.

  17. Hot corrosion behavior of Ni based Inconel 617 and Inconel 738 superalloys

    NASA Astrophysics Data System (ADS)

    El-Awadi, G. A.; Abdel-Samad, S.; Elshazly, Ezzat S.

    2016-08-01

    Superalloys are extensively used at high temperature applications due to their good oxidation and corrosion resistance properties in addition to their high stability were made at high temperature. Experimental measurements of hot corrosion at high temperature of Inconel 617 and Inconel 738 superalloys. The experiments were carried out at temperatures 700 °C, 800 °C and 900 °C for different exposure times to up to 100 h. The corrosive media was NaCl and Na2SO4 sprayed on the specimens. Seven different specimens were used at each temperature. The corrosion process is endothermic and the spontaneity increased by increasing temperature. The activation energy was found to be Ea = 23.54 and Ea = 25.18 KJ/mol for Inconel 738 and Inconel 617 respectively. X-ray diffraction technique (XRD) was used to analyze the formed scale. The morphology of the specimen and scale were examined by scanning electron microscopy (SEM). The results show that the major corrosion products formed were NiCr2O4, and Co Cr2O4 spinles, in addition to Cr2O3.

  18. Hot Corrosion Behavior of Arc-Sprayed Highly Dense NiCr-Based Coatings in Chloride Salt Deposit

    NASA Astrophysics Data System (ADS)

    Qin, Enwei; Yin, Song; Ji, Hua; Huang, Qian; Liu, Zekun; Wu, Shuhui

    2017-03-01

    To make cities more environmentally friendly, combustible wastes tend to be incinerated in waste-to-energy power plant boilers. However, release of chlorine gas (Cl2) during incineration causes serious problems related to hot corrosion of boiler tubes and poses a safety threat for such plants. In this study, a pseudo-de Laval nozzle was employed in a twin-wire arc spray system to enhance the velocity of in-flight particles. Highly dense NiCr-based coatings were obtained using the modified nozzle gun. The coating morphology was characterized by optical microscopy and scanning electron microscopy, and hot corrosion testing was carried out in a synthetic molten chloride salt environment. Results showed that the dense NiCr-based coatings exhibited high resistance against corrosion by chlorine, which can be related to the typical splat lamellar microstructure and chemical composition as well as minor alloying elements such as Ti and Mo.

  19. Hot Corrosion Behavior of Arc-Sprayed Highly Dense NiCr-Based Coatings in Chloride Salt Deposit

    NASA Astrophysics Data System (ADS)

    Qin, Enwei; Yin, Song; Ji, Hua; Huang, Qian; Liu, Zekun; Wu, Shuhui

    2017-04-01

    To make cities more environmentally friendly, combustible wastes tend to be incinerated in waste-to-energy power plant boilers. However, release of chlorine gas (Cl2) during incineration causes serious problems related to hot corrosion of boiler tubes and poses a safety threat for such plants. In this study, a pseudo-de Laval nozzle was employed in a twin-wire arc spray system to enhance the velocity of in-flight particles. Highly dense NiCr-based coatings were obtained using the modified nozzle gun. The coating morphology was characterized by optical microscopy and scanning electron microscopy, and hot corrosion testing was carried out in a synthetic molten chloride salt environment. Results showed that the dense NiCr-based coatings exhibited high resistance against corrosion by chlorine, which can be related to the typical splat lamellar microstructure and chemical composition as well as minor alloying elements such as Ti and Mo.

  20. The hot corrosion of Co-25Cr-10Ni-5Ta-3Al-0.5Y alloy /S-57/

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.

    1978-01-01

    A cobalt-base alloy, Co-25Cr-10Ni-5Ta-3Al-0.5Y (S-57), was subjected to hot corrosion in Mach 0.3 burner-rig combustion gases at maximum alloy temperatures of 900 and 1000 C. Various salt concentrations were injected into the burner: 0.5, 2,5, and 10 parts per million synthetic sea salt and 4 parts per million sodium sulfate (Na2SO4). The extent of corrosion was determined by measuring the maximum depth of corrosion in the alloy, and the corrosion process was studied by metallography, X-ray diffraction, scanning electron microscopy, and electron microprobe analysis. While S-57 was found to possess only moderate oxidation resistance at these temperatures, this alloy resisted significant hot corrosion attack under all but the most severe test conditions. The process of hot corrosion attack under the most severe conditions of this study was primarily sulfidation.

  1. Hot corrosion behavior of low pressure plasma sprayed NiCoCrAlY+Ta coatings on nickel base superalloys

    SciTech Connect

    Frances, M.; Steinmetz, P.; Steinmetz, J.; Duret, C.; Mevrel, R.

    1985-11-01

    The hot corrosion behavior of NiCoCrAlY+Ta coatings obtained by low-pressure plasma spraying has been investigated (type I hot corrosion with T = 850/sup 0/C). These coatings have been deposited on two nickel-base superalloys and on a cast alloy of the same composition as the coating. Comparison of the cyclic oxidation behavior at 850/sup 0/C between the sprayed coating and the cast alloy shows that the sprayed material exhibits a satisfactory and higher resistance than the cast alloy. In the latter case, repeated spalling of the oxide scale results from fractures often associated with Y-rich oxide protrusions. Hot corrosion experiments (salt-spraying test with T = 850/sup 0/C and thermal cycling in air every hour) have been conducted on two cast alloys, NiCoCrAl+Ta and NiCoCrAlY+Ta. The Y-containing alloy has a better corrosion resistance than the other alloy which is subject to extensive oxide spallation. In both cases, morphologies typical of basic fluxing processes, involving Cr, Al, Y, and Ta can be observed in highly attacked zones. Finally, tests on plasma sprayed coatings show a high resistance to hot corrosion of these coatings, regardless of the substrate used: a fine adherent alumina layer is formed, and only a limited fluxing of Cr, Al, and Y takes place. The quite different results obtained on cast and sprayed alloys imply that data relative to cast alloys can be unreliable when one wants to predict high temperature behavior and especially lifetimes of overlay coatings.

  2. Effect of CeO2 on Cyclic Hot-Corrosion Behavior of Detonation-Gun Sprayed Cr3C2-NiCr Coatings on Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Saladi, Sekar; Menghani, Jyoti; Prakash, Satya

    2015-03-01

    The hot-corrosion behavior of detonation-gun sprayed Cr3C2-NiCr coatings with and without 0.4 wt.% CeO2 additive on Ni-based superalloy inconel-718 is comparatively discussed in the present study. Hot-corrosion studies were carried out at 900 °C for 100 cycles in Na2SO4-60%V2O5 molten salt environment under cyclic heating and cooling conditions on bare and coated superalloys. The thermo-gravimetric technique was used to establish kinetics of hot-corrosion. XRD, FESEM/EDAX, and EDX mapping techniques were used to analyze the corrosion products of bare and coated samples. The results indicate that Cr3C2-NiCr-CeO2-coated superalloy showed better hot-corrosion resistance as compared to bare and Cr3C2-NiCr-coated superalloys. The addition of CeO2 has improved micro-hardness, porosity, and surface roughness values of Cr3C2-NiCr-CeO2 coating. The overall weight gain and parabolic rate constant of Cr3C2-NiCr-CeO2-coated superalloy were found to be lowest in the present study signifying that the addition of CeO2 in Cr3C2-NiCr powder has contributed to the development of adherent and dense oxide scale on the coating at elevated temperature.

  3. Hot and cold rolling of high nitrogen Cr-Ni and Cr-Mn austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Ilola, R.; Hänninen, H.; Kauppi, T.

    1998-10-01

    Behavior of austenitic Cr-Ni-(0.14-0.50)N and Cr-Mn-(0.78-1.00)N steels in hot and cold rolling was investigated by rolling experiments and mechanical testing. Structure of the steels in the as-cast condition and fracture surfaces after the rolling experiments were investigated using optical and scanning electron microscopy (SEM). Resistance to deformation was calculated using rolling forces in hot rolling. Increase in strength in the rolling experiments was related to the nitrogen content of the steels. Resistance to deformation during hot rolling increased with decreasing rolling temperature and with increasing nitrogen content. In some steels, hot rolling led to edge cracking, which was more a function of impurity than nitrogen content. Microscopy revealed that the edge cracking occurred along grain boundaries and second phase particles. For the cold-rolled steels, the highest achievable reductions were limited due to a “crocodiling” phenomenon, that is, opening of the strip end. Fracture type at the opened strip end was a brittle-like fracture.

  4. Hot and cold rolling of high nitrogen Cr-Ni and Cr-Mn austenitic stainless steels

    SciTech Connect

    Iiola, R.; Hanninen, H.; Kauppi, T.

    1998-10-01

    Behavior of austenitic Cr-Ni-(0.14--0.50)N and Cr-Mn-(0.78--1.00)N steels in hot and cold rolling was investigated by rolling experiments and mechanical testing. Structure of the steels in the as-cast condition and fracture surfaces after the rolling experiments were investigated using optical and scanning electron microscopy (SEM). Resistance to deformation was calculated using rolling forces in hot rolling. Increase in strength in the rolling experiments was related to the nitrogen content of the steels. Resistance to deformation during hot rolling increased with decreasing rolling temperature and with increasing nitrogen content. In some steels, hot rolling led to edge cracking, which was more a function of impurity than nitrogen content. Microscopy revealed that the edge cracking occurred along grain boundaries and second phase particles. For the cold-rolled steels, the highest achievable reductions were limited due to a crocodiling phenomenon, that is, opening of the strip end. Fracture type at the opened strip end was a brittle-like fracture.

  5. Hot-atom versus Eley-Rideal dynamics in hydrogen recombination on Ni(100). I. The single-adsorbate case.

    PubMed

    Martinazzo, R; Assoni, S; Marinoni, G; Tantardini, G F

    2004-05-08

    We compare the efficiency of the Eley-Rideal (ER) reaction with the formation of hot-atom (HA) species in the simplest case, i.e., the scattering of a projectile off a single adsorbate, considering the Hydrogen and Hydrogen-on-Ni(100) system. We use classical mechanics and the accurate embedded diatomics-in-molecules potential to study the collision system over a wide range of collision energies (0.10-1.50 eV), both with a rigid and a nonrigid Ni substrate and for impact on the occupied and neighboring empty cells. In the rigid model metastable and truly bound hot-atoms occur and we find that the cross section for the formation of bound hot-atoms is considerably higher than that for the ER reaction over the whole range of collision energies examined. Metastable hot-atoms form because of the inefficient energy transfer to the adsorbate and have lifetimes of the order 0.1-0.7 ps, depending on the collision energy. When considering the effects of lattice vibrations we find, on average, a consistent energy transfer to the substrate, say 0.1-0.2 eV, which forced us to devise a two-step dynamical model to get rid of the problems associated with the use of periodic boundary conditions. Results for long-lived HA formation due to scattering on the occupied cell at a surface temperature of 120 K agree well with those of the rigid model, suggesting that in the above process the substrate plays only a secondary role and further calculations at surface temperatures of 50 and 300 K are in line with these findings. However, considerably high cross sections for formation of long-lived hot-atoms result also from scattering off the neighboring cells where the energy transfer to the lattice cannot be neglected. Metastable hot-atoms are reduced in number and have usually lifetimes shorter than those of the rigid-model, say less than 0.3 ps. In addition, ER cross sections are only slightly affected by the lattice motion and show a little temperature dependence. Finally, we find also

  6. Low Temperature Creep of Hot-Extruded Near-Stoichiometric NiTi Shape Memory Alloy. Part I; Isothermal Creep

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Noebe, R. D.

    2013-01-01

    This two-part paper is the first published report on the long term, low temperature creep of hot-extruded near-stoichiometric NiTi. Constant load tensile creep tests were conducted on hot-extruded near-stoichiometric NiTi at 300, 373 and 473 K under initial applied stresses varying between 200 and 350 MPa as long as 15 months. These temperatures corresponded to the martensitic, two-phase and austenitic phase regions, respectively. Normal primary creep lasting several months was observed under all conditions indicating dislocation activity. Although steady-state creep was not observed under these conditions, the estimated creep rates varied between 10(exp -10) and 10(exp -9)/s. The creep behavior of the two phases showed significant differences. The martensitic phase exhibited a large strain on loading followed by a primary creep region accumulating a small amount of strain over a period of several months. The loading strain was attributed to the detwinning of the martensitic phase whereas the subsequent strain accumulation was attributed to dislocation glide-controlled creep. An "incubation period" was observed before the occurrence of detwinning. In contrast, the austenitic phase exhibited a relatively smaller loading strain followed by a primary creep region, where the creep strain continued to increase over several months. It is concluded that the creep of the austenitic phase occurs by a dislocation glide-controlled creep mechanism as well as by the nucleation and growth of deformation twins.

  7. A Study on the Recrystallization Behavior of Ni-Based Alloy G3 During Hot Deformation

    NASA Astrophysics Data System (ADS)

    Jiang, He; Dong, Jianxin; Zhang, Maicang; Yao, Zhihao; Jue, Wang

    2016-12-01

    An integrated microstructure evolution model of thermomechanical processing was developed in terms of dynamic recrystallization (DRX), post-dynamic recrystallization (PDRX) and grain growth. Hot compression tests were carried out on a Gleeble-1500 thermal simulator under different conditions to model DRX, PDRX and short-time grain growth during the post-deformation and cooling process. Furthermore, in combination with the established microstructure evolution models, an elastic-plastic finite element model was built using DEFORM-2D software to simulate the microstructure evolution during the hot extrusion process. The simulation result was compared with the microstructure of a hot-extruded pipe of alloy G3 manufactured in a factory. The simulation results agree well with the experimental ones, validating the accuracy of the established microstructure evolution model. Furthermore, the finite element simulation is an effective method for hot deformation analysis, which can provide theoretical guidance for the optimization manufacturing parameters.

  8. Hot corrosion of Ni-base turbine alloys in atmospheres in coal-conversion systems

    NASA Technical Reports Server (NTRS)

    Huang, T.; Gulbransen, E. A.; Meier, G. H.

    1979-01-01

    Alkali-metal contaminants in coal may form low-melting sulfate salts during coal gasification or subsequent combustion which can have very deleterious effects on turbine components. The mechanisms for the hot-corrosion phenomena are not completely understood.

  9. High-pressure, high-temperature equations of state using nanofabricated controlled-geometry Ni/SiO2/Ni double hot-plate samples

    NASA Astrophysics Data System (ADS)

    Pigott, Jeffrey S.; Ditmer, Derek A.; Fischer, Rebecca A.; Reaman, Daniel M.; Hrubiak, Rostislav; Meng, Yue; Davis, Robert J.; Panero, Wendy R.

    2015-12-01

    We have fabricated novel controlled-geometry samples for the laser-heated diamond-anvil cell (LHDAC) in which a transparent oxide layer (SiO2) is sandwiched between two laser-absorbing layers (Ni) in a single, cohesive sample. The samples were mass manufactured (>104 samples) using a combination of physical vapor deposition, photolithography, and wet and plasma etching. The double hot-plate arrangement of the samples, coupled with the chemical and spatial homogeneity of the laser-absorbing layers, addresses problems of spatial temperature heterogeneities encountered in previous studies where simple mechanical mixtures of transparent and opaque materials were used. Here we report thermal equations of state (EOS) for nickel to 100 GPa and 3000 K and stishovite to 50 GPa and 2400 K obtained using the LHDAC and in situ synchrotron X-ray microdiffraction. We discuss the inner core composition and the stagnation of subducted slabs in the mantle based on our refined thermal EOS.

  10. Characterization of Hot Deformation Behavior of a Fe-Cr-Ni-Mo-N Superaustenitic Stainless Steel Using Dynamic Materials Modeling

    NASA Astrophysics Data System (ADS)

    Pu, Enxiang; Zheng, Wenjie; Song, Zhigang; Feng, Han; Zhu, Yuliang

    2017-03-01

    Hot deformation behavior of a Fe-24Cr-22Ni-7Mo-0.5N superaustenitic stainless steel was investigated by hot compression tests in a wide temperature range of 950-1250 °C and strain rate range of 0.001-10 s-1. The flow curves show that the flow stress decreases as the deformation temperature increases or the strain rate decreases. The processing maps developed on the basis of the dynamic materials model and flow stress data were adopted to optimize the parameters of hot working. It was found that the strain higher than 0.2 has no significant effect on the processing maps. The optimum processing conditions were in the temperature range of 1125-1220 °C and strain rate range of 0.1-3 s-1. Comparing to other stable domains, microstructural observations in this domain revealed the complete dynamic recrystallization (DRX) with finer and more uniform grain size. Flow instability occurred in the domain of temperature lower than 1100 °C and strain rate higher than 0.1 s-1.

  11. Characterization of Hot Deformation Behavior of a Fe-Cr-Ni-Mo-N Superaustenitic Stainless Steel Using Dynamic Materials Modeling

    NASA Astrophysics Data System (ADS)

    Pu, Enxiang; Zheng, Wenjie; Song, Zhigang; Feng, Han; Zhu, Yuliang

    2017-02-01

    Hot deformation behavior of a Fe-24Cr-22Ni-7Mo-0.5N superaustenitic stainless steel was investigated by hot compression tests in a wide temperature range of 950-1250 °C and strain rate range of 0.001-10 s-1. The flow curves show that the flow stress decreases as the deformation temperature increases or the strain rate decreases. The processing maps developed on the basis of the dynamic materials model and flow stress data were adopted to optimize the parameters of hot working. It was found that the strain higher than 0.2 has no significant effect on the processing maps. The optimum processing conditions were in the temperature range of 1125-1220 °C and strain rate range of 0.1-3 s-1. Comparing to other stable domains, microstructural observations in this domain revealed the complete dynamic recrystallization (DRX) with finer and more uniform grain size. Flow instability occurred in the domain of temperature lower than 1100 °C and strain rate higher than 0.1 s-1.

  12. Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloys

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Miller, Robert A.; Sudbrack, Chantal K.; Draper, Susan L.; Nesbitt, James A.; Rogers, Richard B.; Telesman, Ignacy; Ngo, Vanda; Healy, Jonathan

    2016-01-01

    Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 degrees Centigrade and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 degrees Centigrade. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. This cyclic oxidation did not impair the coating's resistance to subsequent hot corrosion pitting attack.

  13. Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloy

    NASA Technical Reports Server (NTRS)

    Gabb, Tim; Miller, R. A.; Sudbrack, C. K.; Draper, S. L.; Nesbitt, J.; Telesman, J.; Ngo, V.; Healy, J.

    2015-01-01

    Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 C and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 C. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. The effects of this cyclic oxidation on resistance to subsequent hot corrosion attack were examined.

  14. An investigation of the initiation stage of hot corrosion in Ni-base alloys

    NASA Technical Reports Server (NTRS)

    Huang, T. T.; Meier, G. H.

    1979-01-01

    The commercial nickel base alloy, IN-738, and high purity laboratory alloys were prepared to simulate the effects of the major elements in IN-738. Results indicate that the initiation of hot corrosion attack of IN-738 and other similar alloys is the result of local penetration of molten salt through the protective oxide scale.

  15. Significant Improvement of Mechanical Properties in NiAl-Cr(Mo)/Hf Alloy by Suction Casting and Subsequent Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Guo, J. T.; Huai, K. W.; Li, H. T.

    2007-01-01

    The NiAl-28Cr-5.5Mo-0.5Hf eutectic alloy was prepared by the suction casting (SC) technique and subsequent hot isostatic pressing (HIP) treatment, and tested for compressive strength and fracture behavior in the temperature range of 300 to 1373 K. The microstructure of suction-cast alloy is characterized by fine interlamellar spacing, large area fraction of eutectic cell, and fine Heusler (Ni2AlHf) phase distributed semicontinuously at the cell boundaries. After HIP treatment, Ni2AlHf phase at the cell boundaries is transformed into Hf solid solution phase and distributed homogeneously within the NiAl matrix. Compared with the conventionally cast alloy, the room-temperature compressive strain and elevated temperature strength of suction-cast alloy are enhanced markedly after HIP treatment. The reason is that the HIP treatment causes Hf solid solution phase to distribute homogeneously and then strengthens the NiAl matrix.

  16. Static Softening in a Ni-30Fe Austenitic Model Alloy After Hot Deformation: Microstructure and Texture Evolution

    NASA Astrophysics Data System (ADS)

    Beladi, Hossein; Cizek, Pavel; Taylor, Adam S.; Rohrer, Gregory S.; Hodgson, Peter D.

    2017-02-01

    In the current study, the microstructure and texture characteristics of a model Ni-30Fe austenitic alloy were investigated during hot deformation and subsequent isothermal holding. The deformation led to the formation of self-screening arrays of microbands within a majority of grains. The microbands characteristics underwent rather modest changes during the post-deformation annealing, which suggests that limited dislocation annihilation occurs within the corresponding dislocation walls. The fraction of statically recrystallized (SRX) grains progressively increased with the holding time and closely matched the softening fraction measured from the offset flow stress approach. The corresponding texture was weak and preserved its character with the holding time. There was no pronounced temperature effect on the grain boundary character distribution after the completion of SRX. The Σ3 and Σ9 coincidence site lattice boundaries were characterized as (111) pure twist and (1-14) symmetric tilt types, respectively. Nonetheless, the recrystallization temperature slightly affected the grain boundary network.

  17. A Comparative Study of Cyclic Oxidation and Sulfates-Induced Hot Corrosion Behavior of Arc-Sprayed Ni-Cr-Ti Coatings at Moderate Temperatures

    NASA Astrophysics Data System (ADS)

    Guo, Wenmin; Wu, Yuping; Zhang, Jianfeng; Hong, Sheng; Chen, Liyan; Qin, Yujiao

    2015-06-01

    The cyclic oxidation and sulfates-induced hot corrosion behaviors of a Ni-43Cr-0.3Ti arc-sprayed coating at 550-750 °C were characterized and compared in this study. In general, all the oxidation and hot corrosion kinetic curves of the coating followed a parabolic law, i.e., the weight of the specimens showed a rapid growth initially and then reached the gradual state. However, the initial stage of the hot corrosion process was approximately two times longer than that of the oxidation process, indicating a longer preparation time required for the formation of a protective scale in the former process. At 650 °C, the parabolic rate constant for the hot corrosion was 7.2 × 10-12 g2/(cm4·s), approximately 1.7 times higher than that for the oxidation at the same temperature. The lower parabolic rate constant for the oxidation was mainly attributed to the formation of a protective oxide scale on the surface of corroded specimens, which was composed of a mixture of NiO, Cr2O3, and NiCr2O4. However, as the liquid molten salts emerged during the hot corrosion, these protective oxides would be dissolved and the coating was corrupted acceleratedly.

  18. Growing hot pepper for cabbage looper, Trichopulsia ni (Hübner) and spider mite, Tetranychus urticae (Koch) control.

    PubMed

    Antonious, George F; Meyer, Janet E; Rogers, Jami A; Hu, Yoon-Hyeon

    2007-01-01

    With the public perception that synthetic pesticides leave harmful residues in crop produce for human consumption, there has been increased interest in using natural products for pest control. The potential of using fruit extracts of hot pepper for controlling the cabbage looper, Trichopulsia ni (Hübner) and spider mite, Tetranychus urticae Koch is explored in this investigation. Crude extracts from fruits of Capsicum chinense, C. frutescens, C. baccatum, and C. annuum, were prepared and tested under laboratory conditions for their insecticidal and acaricidal performance. Mortality was greatest (94%) when fruit extract of accession PI-593566 (C. annuum) was sprayed on larvae of the cabbage looper, while crude extracts of accessions PI-241675 (C. frutescens) and PI-310488 (C. annuum) were repellent to the spider mite. We investigated differences in chemical composition of the crude fruit extracts that may explain the observed differences in mortality and repellency between accessions. Gas Chromatography-Mass Spectrometry spectrometric analysis revealed that capsaicin and dihydrocapsaicin, the pungent components of pepper fruit, were not correlated with toxicity or repellency, indicating that the two capsaicinoids are not likely related to the efficacy of pepper fruit extracts. Major compounds in hot pepper fruit extracts were detected and identified as pentadecanoic acid methyl ester, hexadecanoic acid methyl ester, and octadecanoic acid methyl ester. Spectrometric analysis and toxicity to cabbage looper larvae revealed that pentadecanoic acid methyl ester is likely related to cabbage looper mortality. However, the concentration of pentadecanoic acid methyl ester in some accessions was insufficient to explain the observed mortality of cabbage looper and repellency of spider mite. Fruit extracts of accessions PI-593566 (C. annuum) and PI-241675 (C. frutescens) could be useful for managing populations of cabbage loopers and spider mites, which could reduce reliance

  19. Effect of Water Vapor During Secondary Cooling on Hot Shortness in Fe-Cu-Ni-Sn-Si Alloys

    NASA Astrophysics Data System (ADS)

    Sampson, Erica; Sridhar, Seetharaman

    2014-10-01

    Residual Cu in recycled steel scrap can cause hot shortness when the iron matrix is oxidized. Hot shortness can occur directly after the solid steel is formed from continuous casting as the steel undergoes a cooling process known as secondary cooling where water is first sprayed on the surface to promote cooling. This is followed by a radiant cooling stage where the steel is cooled in air to room temperature. This investigation examines the roles of water vapor, Si content, temperature, and the presence of Sn in a Fe-0.2 wt pct Cu-0.05 wt pct Ni alloy on oxidation, separated Cu and Cu induced-hot shortness during simulations of the secondary cooling process. The secondary cooling from 1473 K (1200 °C) resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles at 1423 K (1150 °C) due to the higher temperatures experienced in the non-isothermal cycle. The addition of water vapor increased the sample oxidation as compared to samples processed in dry atmospheres due to increased scale adherence, scale plasticity, and inward transport of oxygen. The increase in weight gain of the wet atmosphere increased the liquid formation at the interface in the non-Si containing alloys. The secondary cooling cycle with water vapor and the effect of Sn lead to the formation of many small pools of Cu-rich liquid embedded within the surface of the metal due to the Sn allowing for increased grain boundary decohesion and the water vapor allowing for oxidation within liquid-penetrated grain boundaries. The presence of Si increased the amount of occlusion of Cu and Fe, significantly decreasing the quantity of liquid at the interface and the amount of grain boundary penetration.

  20. The discovery of Ni V in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B

    NASA Technical Reports Server (NTRS)

    Holberg, J. B.; Hubeny, I.; Barstow, M. A.; Lanz, T.; Sion, E. M.; Tweedy, R. W.

    1994-01-01

    We have co-added six recently obtained International Ultraviolet Explorer (IUE) echelle spectra of the hot DA white dwarf RE 2214-492 and 10 existing archive spectra of the well-known hot DA, G191-B2B. We find that both stars contain numerous weak features due to Ni V. Nickel is thus the second iron-group element to be found in the spectra of the very hottest DA white dwarfs. In addition to Ni V, we also observe Al III in both stars and present evidence for the possible presence of Ni IV and Fe IV in RE 2214-492. The presence of Ni and Al, together with previously reported elements, will contribute significantly to both the EUV opacity and to the apparent complexity of the UV spectra of these stars. Using Non-Local Thermodynamic Equilibrium (NLTE) model atmospheres we estimate the Ni abundances in RE 2214-492 the G191-B2B to be log(Ni/H) = -5.5 +/- 0.3 and -6.0 +/- 0.3, respectively.

  1. Hot Corrosion Performance of AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa Coatings Deposited by Atmospheric Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Tao, Chong; Wang, Lei; Cheng, Nailiang; Hu, Hengfa; Liu, Yang; Song, Xiu

    2016-04-01

    AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa coatings were deposited on 316L stainless steel substrate using atmospheric plasma spraying, respectively, in order to improve the oxidation and corrosion resistance. The hot corrosion performance of the coatings at 700 and 900 °C were studied, and the detailed microstructures and phase composition of the coatings were analyzed using x-ray diffraction, scanning electron microscope with energy dispersive spectrometer, and transmission electron microscope. The results show that both coatings are structurally featured by slatted layers, consisting of amorphous phase, Cr2O3, Ni3Al, and Al2O3. The hot corrosion resistance of AlO-CrO/NiCoCrAlYTa coating is better than that of AlO/NiCoCrAlYTa coating. This improvement is attributed to lower porosity and more compact Cr2O3 in AlO-CrO/NiCoCrAlYTa coating which performs better than Al2O3 in blocking further inward progress of corrosion and oxidization.

  2. High-pressure, high-temperature equations of state using nanofabricated controlled-geometry Ni/SiO2/Ni double hot-plate samples

    SciTech Connect

    Pigott, Jeffrey S.; Ditmer, Derek A.; Fischer, Rebecca A.; Reaman, Daniel M.; Hrubiak, Rostislav; Meng, Yue; Davis, Robert J.; Panero, Wendy R.

    2015-11-24

    We have fabricated novel controlled-geometry samples for the laser-heated diamond anvil cell (LHDAC) in which a transparent oxide layer (SiO2) is sandwiched between two laser-absorbing layers (Ni) in a single, cohesive sample. The samples were mass manufactured (>104 samples) using a combination of physical vapor deposition, photolithography, and wet and plasma etching. The double hot-plate arrangement of the samples, coupled with the chemical and spatial homogeneity of the laser-absorbing layers, addresses problems of spatial temperature heterogeneities encountered in previous studies where simple mechanical mixtures of transparent and opaque materials were used. Here we report thermal equations of state (EOS) for nickel to 100 GPa and 3000 K and stishovite to 50 GPa and 2400 K obtained using the LHDAC and in situ synchrotron x-ray micro-diffraction. Lastly, we discuss the inner core composition and the stagnation of subducted slabs in the mantle based on our refined thermal EOS.

  3. High-pressure, high-temperature equations of state using nanofabricated controlled-geometry Ni/SiO2/Ni double hot-plate samples

    DOE PAGES

    Pigott, Jeffrey S.; Ditmer, Derek A.; Fischer, Rebecca A.; ...

    2015-11-24

    We have fabricated novel controlled-geometry samples for the laser-heated diamond anvil cell (LHDAC) in which a transparent oxide layer (SiO2) is sandwiched between two laser-absorbing layers (Ni) in a single, cohesive sample. The samples were mass manufactured (>104 samples) using a combination of physical vapor deposition, photolithography, and wet and plasma etching. The double hot-plate arrangement of the samples, coupled with the chemical and spatial homogeneity of the laser-absorbing layers, addresses problems of spatial temperature heterogeneities encountered in previous studies where simple mechanical mixtures of transparent and opaque materials were used. Here we report thermal equations of state (EOS) formore » nickel to 100 GPa and 3000 K and stishovite to 50 GPa and 2400 K obtained using the LHDAC and in situ synchrotron x-ray micro-diffraction. Lastly, we discuss the inner core composition and the stagnation of subducted slabs in the mantle based on our refined thermal EOS.« less

  4. Hot corrosion of Co-Cr, Co-Cr-Al, and Ni-Cr alloys in the temperature range of 700-750 deg C

    NASA Technical Reports Server (NTRS)

    Chiang, K. T.; Meier, G. H.

    1980-01-01

    The effect of SO3 pressure in the gas phase on the Na2SO4 induced hot corrosion of Co-Cr, Ni-Cr, and Co-Cr-Al alloys was studied in the temperature range 700 to 750 C. The degradation of the Co-Cr and Ni-Cr alloys was found to be associated with the formation of liquid mixed sulfates (CoSO4-Na2SO4 or NiSO4-Na2SO4) which provided a selective dissolution of the Co or Ni and a subsequent sulfidation oxidation mode of attack which prevented the maintenance of a protective Cr2O3 film. A clear mechanism was not developed for the degradation of Co-Cr-Al alloys. A pitting corrosion morphology was induced by a number of different mechanisms.

  5. Deformation Behavior and Microstructure Evolution of the Cu-2Ni-0.5Si-0.15Ag Alloy During Hot Compression

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Volinsky, Alex A.; Xu, Qian-Qian; Chai, Zhe; Tian, Baohong; Liu, Ping; Tran, Hai T.

    2015-12-01

    Hot deformation behavior of the Cu-2Ni-0.5Si-0.15Ag alloy was investigated by hot compression tests using the Gleeble-1500D thermo-simulator in the 873 K to 1073 K (600 °C to 800 °C) temperatures range with the 0.01 to 5 s-1 strain rate. The flow stress strongly depends on the deformation parameters, including temperature and strain rate. The flow stress decreases with the deformation temperature and increases with the strain rate. The constitutive relationship between the peak stress, the strain rate, and the deformation temperature can be described by the Zener-Hollomon Z parameter in the hyperbolic sine function with the hot deformation activation energy of 316 kJ/mol. The dynamic recrystallization (DRX) is one of the important softening mechanisms of the Cu-2Ni-0.5Si-0.15Ag alloy during hot deformation. The DRX behavior of the Cu-2Ni-0.5Si-0.15Ag alloy is strongly affected by the Z parameter. Lower Z parameter leads to more adequate DRX proceeding.

  6. The effect of hot-rolling on chill-cast AI-AI3Ni, chill-cast AI-AI2Cu, and Unidirectionally Solidified AI-AI3Ni Eutectic Alloys

    NASA Astrophysics Data System (ADS)

    Jardine, F. S. J.; Cantor, B.

    1986-11-01

    The effect of hot-rolling on the mechanical properties and microstructures of chill-cast Al-Al3Ni, chill-cast Al-Al2Cu, and unidirectionally solidified Al-Al3Ni eutectic alloys has been studied. The chill-cast eutectic alloys were produced by casting into preheated mild steel molds placed on copper chills. This system promoted growth along the length of the ingot and not radially from the mold wall. Cellular microstructures resulted with good alignment of Al3Ni fibers or Al2Cu lamellae within the cells and an interfiber/lamellar spacing of ~ 1 /urn. In contrast, the Al-Al3Ni eutectic alloy was also unidirectionally solidified at a growth rate of 3 x 10-1 m s-1 in a conventional horizontal crystal grower. This produced well-aligned Al3Ni fibers with an interfiber spacing of 1.2 ώm. Both the unidirectionally solidified and chill-cast Al-Al3Ni eutectic alloy can be hot-rolled at 773 K to reductions in area of greater than 95 pct. Deformation was achieved by Al3Ni fiber fracturing followed by separation of the broken fiber fragments in the rolling direction. Additionally, for the chill-cast eutectic the cellular microstructure disappeared and the Al3Ni fibers were homogeneously distributed throughout the matrix, after area reductions of 60 to 70 pct. In both cases, the eutectic microstructure was deformed with a constant volume fraction of Al3Ni/unit volume being maintained during rolling. The chill-cast Al-Al2Cu eutectic alloy can be hot-rolled at 773 K to an area reduction of ~50 pct, after the continuous brittle Al2Cu phase within the cells has been ‘broken up’ by coarsening at high temperature. The variations of room temperature tensile properties for the chill-cast and unidirectionally solidified eutectic alloys were measured as a function of reduction of thickness during hot-rolling and the results were compared with predicted strengths from discontinuous fiber reinforcement theory.

  7. An investigation of the initiation stage of hot corrosion in Ni-base alloys

    NASA Technical Reports Server (NTRS)

    Huang, T. T.; Meier, G. H.

    1979-01-01

    The mechanisms which lead to the destruction of a normally protective scale during the initial stages of hot corrosion of 14 nickel-base alloys contaminated with Na2SO4 and other condensed deposits were investigated. A continuous reading microbalance was used to record weight changes at temperatures between 900 C and 1000 C at 1 atmosphere pressure of slowly flowing oxygen. The reaction was initiated by raising a preheated furnace around the quartz tube in which the specimen was supported with oxygen flowing. The furnace was raised in a time period of seconds. At 900 C, the system and specimen came to thermal equilibrium in less than one minute. Oxidized specimens were studied using optical and scanning electron metallography and X-ray diffraction techniques. Transmission electron microscopy and electron diffraction spectroscopy were also used to identify the structure of carbides in some of the commercial alloys.

  8. Long-term high-velocity oxidation and hot corrosion testing of several NiCrAl and FeCrAl base oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Several oxide dispersion strengthened (ODS) alloys have been tested for cyclic, long-term, high gas-velocity resistance to oxidation at 1100 C and hot corrosion at 900 C. Both nominally Ni-16Cr-4Al and Fe-20Cr-4.5Al ODS alloys were subjected up to about 2500 cycles, where each cycle consisted of 1 hr in a hot, Mach 0.3 combusted gas stream followed by a 3-min quench in an ambient temperature, Mach 0.3 air blast. For comparison to existing technology, a coated superalloy was simultaneously tested. The ODS iron alloy exhibited clearly superior behavior, surviving 3800 oxidation and 2300 hot corrosion cycles essentially unscathed. While the ODS nickel alloys exhibited adequate oxidation resistance, the long-term hot corrosion resistance could be marginal, since the best life for such alloys under these conditions was only about 1100 cycles. However, the hot corrosion resistance of the ODS Ni-base alloys is excellent in comparison to that of traditional superalloys.

  9. Long-term high-velocity oxidation and hot corrosion testing of several NiCrAl and FeCrAl base oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Several oxide dispersion strengthened (ODS) alloys have been tested for cyclic, long-term, high gas-velocity resistance to oxidation at 1100 C and hot corrosion at 900 C. Both nominally Ni-16Cr-4Al and Fe-20Cr-4.5Al ODS alloys were subjected up to about 2500 cycles, where each cycle consisted of 1 hr in a hot, Mach 0.3 combusted gas stream followed by a 3-min quench in an ambient temperature, Mach 0.3 air blast. For comparison to existing technology, a coated superalloy was simultaneously tested. The ODS iron alloy exhibited clearly superior behavior, surviving 3800 oxidation and 2300 hot corrosion cycles essentially unscathed. While the ODS nickel alloys exhibited adequate oxidation resistance, the long-term hot corrosion resistance could be marginal, since the best life for such alloys under these conditions was only about 1100 cycles. However, the hot corrosion resistance of the ODS Ni-base alloys is excellent in comparison to that of traditional superalloys.

  10. Hot Deformation Behavior of 1Cr12Ni3Mo2VN Martensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    He, Xiaomao; Jiang, Peng; Zhou, Leyu; Chen, Chao; Deng, Xiaochun

    2017-08-01

    1Cr12Ni3Mo2VN is a new type of martensitic stainless steel for the last-stage blades of large-capacity nuclear and thermal power turbines. The deformation behavior of this steel was studied by thermal compression experiments that performed on a Gleeble-3500 thermal simulator at a temperature range of 850°C to 1200°C and a strain rate of 0.01s-1 to 20s-1. When the deformation was performed at high temperature and low strain rate, a necklace type of microstructures was observed, the plastic deformation mechanism is grain boundary slip and migration, when at low temperature and lower strain rate, the slip bands were observed, the mechanism is intracrystalline slips, and when at strain rate of 20s-1, twins were observed, the mechanism are slips and twins. The Arrhenius equation was applied to describe the constitutive equation of the flow stress. The accuracy of the equation was verified by using the experimental data and the correlation coefficient R2 = 0.9786, and the equation can provide reasonable data for the design and numerical simulation of the forging process.

  11. Evolution of Microstructure and Texture During Hot Compression of a Ni-Fe-Cr Superalloy

    NASA Astrophysics Data System (ADS)

    Coryell, S. P.; Findley, K. O.; Mataya, M. C.; Brown, E.

    2012-02-01

    Superalloys are being employed in more extreme conditions requiring higher strength, which requires producers to forge products to finer grain sizes with less grain size variability. To assess grain size, crystallographic texture, and substructure as a function of forging conditions, frictionless uniaxial compression testing characteristic of hot working was performed on INCOLOY 945 (Special Metals Corporation, Huntington, WV), which is a newly developed hybrid of alloys 718 and 925, over a range of temperatures and strain rates. The microstructure and texture were investigated comprehensively using light optical microscopy, electron backscatter diffraction (EBSD), electron channeling contrast imaging (ECCI), and transmission electron microscopy (TEM) to provide detailed insight into microstructure evolution mechanisms. Dynamic recrystallization, nucleated by grain/twin boundary bulging with occasional subgrain rotation, was found to be a dominant mechanism for grain refinement in INCOLOY 945. At higher strain rates, static recrystallization occurred by grain boundary migration. During deformation, duplex slip along {111} planes occurred until a stable <110> fiber compression texture was established. Recrystallization textures were mostly random but shifted toward the compression texture with subsequent deformation. An exception occurred at 1423 K (1150 °C) and 0.001 seconds-1, the condition with the largest fraction of recrystallized grains, where a <100> fiber texture developed, which may be indicative of preferential growth of specific grain orientations.

  12. A Feasibility Study of Applying SS 307Si Buffer Layer for Mitigating the Hot Cracking of Ni-Based Weld Overlay

    NASA Astrophysics Data System (ADS)

    Tsai, Kun-Chao; Jeng, Sheng-Long

    2017-08-01

    The hot cracking behavior of Ni-based Alloy 52M weld overlay with respective SS 307Si and SS 308L buffer layers was investigated. The dilution level of SS 307Si buffer layer is a little higher than that of SS 308L. However, the hot crack length of overlay with SS 307Si buffer layer is shorter and the SS 307Si layer has higher mechanical properties than that of SS 308L layer. As observed by SEM and EBSD, ferrites precipitated in SS 307Si buffer layer are in vermicular skeletons dotted with lathy precipitates, which have a little higher local stain than that of SS 308L weld. However, Alloy 52M weld around SS 307Si fusion boundary has a lower degree of local distortion. The results generalize that the SS 307Si buffer layer is marginally better for reducing hot cracking susceptibility, owing to its lower local stain and slightly higher mechanical strength.

  13. A Feasibility Study of Applying SS 307Si Buffer Layer for Mitigating the Hot Cracking of Ni-Based Weld Overlay

    NASA Astrophysics Data System (ADS)

    Tsai, Kun-Chao; Jeng, Sheng-Long

    2017-07-01

    The hot cracking behavior of Ni-based Alloy 52M weld overlay with respective SS 307Si and SS 308L buffer layers was investigated. The dilution level of SS 307Si buffer layer is a little higher than that of SS 308L. However, the hot crack length of overlay with SS 307Si buffer layer is shorter and the SS 307Si layer has higher mechanical properties than that of SS 308L layer. As observed by SEM and EBSD, ferrites precipitated in SS 307Si buffer layer are in vermicular skeletons dotted with lathy precipitates, which have a little higher local stain than that of SS 308L weld. However, Alloy 52M weld around SS 307Si fusion boundary has a lower degree of local distortion. The results generalize that the SS 307Si buffer layer is marginally better for reducing hot cracking susceptibility, owing to its lower local stain and slightly higher mechanical strength.

  14. Process and performance of hot dip zinc coatings containing ZnO and Ni-P under layers as barrier protection

    NASA Astrophysics Data System (ADS)

    Hamid, Z. Abdel; Aal, A. Abdel; Hassan, H. B.; Shaaban, A.

    2010-04-01

    A new coating system of under layer for hot dip zinc coating was explored as an effective coating for steel especially for application in relatively high aggressive environments. The influence of different barrier layers formed prior to hot dip galvanization was investigated to optimize high performance protective galvanic coatings. The deposition of ZnO and Ni-P inner layers and characteristics of hotdip zinc coatings were explored in this study. The coating morphology was characterized by scanning electron microscope (SEM) analysis. The hot dip zinc coatings containing under layer showed substantial improvement in their properties such as good adhesion, and high hardness. In addition, a decrease in the thickness of the coating layer and an enhancement of the corrosion resistance were found. Open circuit potential (OCP) of different galvanized layers in different corrosive media viz. 5% NaCl and 0.5 M H 2SO 4 solutions at 25 ± 1 °C was measured as a function of time. A nobler OCP was exhibited for samples treated with ZnO and Ni than sample of pure Zn; this indicates a dissolution process followed by passivation due to the surface oxide formation. The high negative OCP can be attributed to the better alloying reaction between Zn and Fe and to the sacrificial nature of the top pure zinc layer.

  15. The nonlinear unloading behavior of a typical Ni-based superalloy during hot deformation: a unified elasto-viscoplastic constitutive model

    NASA Astrophysics Data System (ADS)

    Chen, Ming-Song; Lin, Y. C.; Li, Kuo-Kuo; Chen, Jian

    2016-09-01

    In authors' previous work (Chen et al. in Appl Phys A. doi: 10.1007/s00339-016-0371-6, 2016), the nonlinear unloading behavior of a typical Ni-based superalloy was investigated by hot compressive experiments with intermediate unloading-reloading cycles. The characters of unloading curves were discussed in detail, and a new elasto-viscoplastic constitutive model was proposed to describe the nonlinear unloading behavior of the studied Ni-based superalloy. Still, the functional relationships between the deformation temperature, strain rate, pre-strain and the parameters of the proposed constitutive model need to be established. In this study, the effects of deformation temperature, strain rate and pre-strain on the parameters of the new constitutive model proposed in authors' previous work (Chen et al. 2016) are analyzed, and a unified elasto-viscoplastic constitutive model is proposed to predict the unloading behavior at arbitrary deformation temperature, strain rate and pre-strain.

  16. An Electron Microprobe Determination of Microscopic Elemental Homogeneity of Hot-Cross-Rolled and High-Energy-Rate Forged 21Cr-6Ni-9Mn Steel

    SciTech Connect

    Mosley, W.C.

    1981-02-17

    Electron microprobe analysis shows that iron, manganese, and nickel are inhomogeneously distributed in hot-cross-rolled plate and high-energy-rate forgings of 21Cr-6Ni-9Mn steel but that chromium is homogeneously distributed. Increases in iron content correlate with decreases in manganese and nickel. Rolling and forging flow lines occur in regions with high iron and low manganese and nickel. High-energy-rate forging increases inhomogeneity. Inhomogeneities are suspected to exist in the original ingot, where they are given directionality by rolling and are enhanced by high-energy-rate forging. This report discusses this study.

  17. Hot Corrosion Studies of Detonation-Gun-Sprayed NiCrAlY + 0.4 wt.% CeO2 Coated Superalloys in Molten Salt Environment

    NASA Astrophysics Data System (ADS)

    Kamal, Subhash; Jayaganthan, R.; Prakash, Satya

    2011-08-01

    Rare earth oxide (CeO2) has been incorporated in NiCrAlY alloy and hot corrosion resistance of detonation-gun-sprayed NiCrAlY + 0.4 wt.% CeO2 coatings on superalloys, namely, superni 75, superni 718, and superfer 800H in molten 40% Na2SO4-60% V2O5 salt environment were investigated at 900 °C for 100 cycles. The coatings exhibited characteristic splat globular dendritic structure with diameter similar to the original powder particles. The weight change technique was used to establish corrosion kinetics. X-ray diffraction (XRD), field emission scanning electron microscopy/energy-dispersive analysis (FE-SEM/EDAX), and x-ray mapping techniques were used to analyze the corrosion products. Coated superfer 800H alloy showed the highest corrosion resistance among the examined superalloys. CeO2 was found to be distributed in the coating along the splat boundaries, whereas Al streaks distributed non-uniformly. The main phases observed for the coated superalloys are oxides of Ni, Cr, Al, and spinels, which are suggested to be responsible for developing corrosion resistance.

  18. Corrosion behavior of Ni-Base alloys in a hot lithium molten salt under an oxidizing atmosphere

    NASA Astrophysics Data System (ADS)

    Cho, Soo-Haeng; Cho, Il-Je; You, Gil-Sung; Yoon, Ji-Sup; Park, Seong-Won

    2007-08-01

    The electrolytic reduction of a spent oxide fuel involves the liberation of the oxygen in molten LiCl electrolyte, which is a chemically aggressive environment that is excessively corrosive for typical structural materials. Accordingly, it is essential to choose the optimum material for the processing equipment that handles the molten salt. In this study, the corrosion behaviors of Haynes 263, Haynes 75, Inconel 718 and Inconel X-750 in a molten LiCl-Li2O salt under an oxidizing atmosphere were investigated at 650°C for 72 to 216 hrs. The Haynes 263 alloy showed the best corrosion resistance among the examined alloys. The corrosion products of Haynes 263 were Li(Ni,Co)O2 and LiTiO2; those of Haynes 75 were Cr2O3, NiFe2O4, LiNiO2 and Li2FiFe2O4; while Cr2O3, NiFe2O4 and CrNbO4 were identified as the corrosion products of Inconel 718. Inconel X-750 produced Cr2O3, NiFe2O4 and (Cr, Nb, Ti)O2 as its corrosion products. Haynes 263 showed a localized corrosion behavior while Haynes 75, Inconel 718 and Inconel X-750 showed a uniform corrosion behavior.

  19. Room Temperature Ductility of NiAl-strengthened Ferritic Steels: Effects of Precipitate Microstructure and Hot Rolling

    SciTech Connect

    Teng, Zhenke; Liu, Chain T; Miller, Michael K; Ghosh, Gautam; Kenik, Edward A; Huang, Shenyan; Liaw, Peter K

    2012-01-01

    The effects of precipitate microstructure on the room temperature ductility of a series of carefully designed Fe-Al-Ni-Cr-Mo steels were investigated. Transmission electron microscopy (TEM), ultra small angle X-ray scattering (USAXS), and atom probe tomography (APT) were conducted to quantify the nano-scaled precipitates. The accuracy of the characterization results was verified by a numerical analysis. Three point bending tests results demonstrated that ductility was a function of the precipitate volume fraction and the Al and Ni concentrations in the Fe matrix, these relationships were discussed in terms of possible mechanisms. The ductility was also found to be independent of the precipitate size and inter-particle spacing in the studied range, which was validated by a theoretical model.

  20. Modeling constitutive behavior of a 15Cr-15Ni-2.2Mo-Ti modified austenitic stainless steel under hot compression using artificial neural network

    NASA Astrophysics Data System (ADS)

    Mandal, Sumantra

    2006-11-01

    ABSTRACT In this paper, an artificial neural network (ANN) model has been suggested to predict the constitutive flow behavior of a 15Cr-15Ni-2.2Mo-Ti modified austenitic stainless steel under hot deformation. Hot compression tests in the temperature range 850°C- 1250°C and strain rate range 10-3-102 s-1 were carried out. These tests provided the required data for training the neural network and for subsequent testing. The inputs of the neural network are strain, log strain rate and temperature while flow stress is obtained as output. A three layer feed-forward network with ten neurons in a single hidden layer and back-propagation learning algorithm has been employed. A very good correlation between experimental and predicted result has been obtained. The effect of temperature and strain rate on flow behavior has been simulated employing the ANN model. The results have been found to be consistent with the metallurgical trend. Finally, a monte carlo analiysis has been carried out to find out the noise sensitivity of the developed model.

  1. High-Pressure, High-Temperature Equations of State Using Fabricated Controlled-Geometry Ni/SiO2 Double Hot-Plate Samples

    NASA Astrophysics Data System (ADS)

    Pigott, J. S.; Ditmer, D. A.; Fischer, R. A.; Reaman, D. M.; Davis, R. J.; Panero, W. R.

    2014-12-01

    To model and predict the structure, dynamics, and composition of Earth's deep interior, accurate and precise measurements of thermal expansion and compressibility are required. The laser-heated diamond-anvil cell (LHDAC) coupled with synchrotron-based x-ray diffraction (XRD) is a powerful tool to determine pressure-volume-temperature (P-V-T) relationships. However, LHDAC experiments may be hampered by non-uniform heating caused by the mixing of transparent materials with opaque laser absorbers. Additionally, radial temperature gradients are exacerbated by small misalignments (1-3 µm) of the x-ray beam with respect to the center of the laser-heated hotspot. We have fabricated three-dimensional, controlled-geometry, double hot-plate samples. In this double hot-plate arrangement, a transparent oxide layer (SiO2) is sandwiched between two laser absorbing layers (Ni) in a single, cohesive sample. These samples were mass manufactured (>105 samples) using a combination of physical vapor deposition, photolithography, wet etching, and plasma etching. The double hot-plate arrangement coupled with the chemical and spatial homogeneity of the laser absorbing layers addresses problems caused by mixtures of transparent and opaque samples. The controlled-geometry samples have dimensions of 50 μm x 50 μm x 1.4 μm. The dimensions of the samples are much larger than the synchrotron x-ray beam. With a heating laser FWHM of ~50 μm, the radial temperature gradients within the volume probed by the x-ray are reduced. We conducted XRD experiments to P > 50 GPa and T > 2200 K at beamline 16-ID-B (HPCAT) of the Advanced Photon Source. Here we present relevant thermal modeling of the LHDAC environment along with Ni and SiO2 P-V-T equations of state. Our photolithography method of sample fabrication can be extended to different materials including but not limited to Fe and MgO.

  2. Microstructural Evolution and Flow Analysis during Hot Working of a Fe-Ni-Cr Superaustenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Momeni, Amir; Dehghani, Kamran

    2011-07-01

    Hot compression tests were conducted in a temperature range of 1173 K to 1323 K (900 °C to 1050 °C) and strain rates of 0.001 seconds-1 to 1 second-1 to investigate the hot deformation behavior of the austenitic stainless steel type 1.4563. The results showed that hot deformation at low temperatures, i.e., 1173 K to 1223 K (900 °C to 950°C), and at low and medium strain rates, i.e., 0.001 seconds-1 to 0.1 seconds-1, results in the dynamic formation of worm-like precipitates on existing grain boundaries. This in turn led to the restriction or even inhibition of dynamic recrystallization. However, at higher temperatures and strain rates when either the time frame for dynamic precipitation was too short or the driving force was low, dynamic recrystallization occurred readily. Furthermore, at low strain rates and high temperatures, there was no sign of particles, but the interactions between solute atoms and mobile dislocations made the flow curves serrated. The strain rate sensitivity was determined and found to change from 0.1 to 0.16 for a temperature increase from 1173 K to 1323 K (900 °C to 1050 °C). The variations of mean flow stress with strain rate and temperature were analyzed. The calculated apparent activation energy for the material was approximately 406 kJ/mol. The hyperbolic sine function correlated the Zener-Hollomon parameter and flow stress successfully at intermediate stress levels. However, at low levels of flow stress a power-law equation and at high stresses an exponential equation well fitted the experimental data.

  3. Hot Corrosion Behavior of Cold-Sprayed Ni-50Cr Coating in an Incinerator Environment at 900 °C

    NASA Astrophysics Data System (ADS)

    Singh, Harminder; Sidhu, T. S.; Kalsi, S. B. S.; Karthikeyan, J.

    2015-02-01

    In the present study, 50%Ni-50%Cr coating was developed on Superni 75 superalloy by a novel and facile cold-spray coating deposition technique. Dense, adhered, and oxide-free cold-sprayed coating was obtained in this study. This coating effectively provided corrosion protection to the substrate in real service incinerator conditions at 900 °C. The corrosion rate of the coated alloy was 0.47 mm/year, compared with 1.04 mm/year for bare alloy. This study indicates that the cold-spray process is an effective alternative for depositing high-temperature corrosion-resistant coatings.

  4. Evaporation residue cross sections for the {sup 64}Ni + {sup 144,154}Sm reaction -- Energy dissipation in hot nuclei

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Davids, C.N.

    1995-08-01

    The fission hindrance of hot nuclei was deduced recently from an enhanced emission of GDR {gamma} rays, neutrons and charged particles prior to scission of heavy nuclei. In the most recent experiments addressing this topic, namely new measurements of the pre-scission {gamma} rays and evaporation residues from the {sup 32}S + {sup 184}W reaction, a rather sharp transition from negligible to full one-body dissipation occurs over the excitation energy region E{sub exc} = 60-100 MeV. However, the cross section does not appear to level out or start to decline again at the upper end of the energy range as expected in this interpretation. It is therefore clearly desirable to extend the excitation energy range to look for such an effect in order to either corroborate or refute this interpretation.

  5. A micro-scale hot wire anemometer based on low stress (Ni/W) multi-layers deposited on nano-crystalline diamond for air flow sensing

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Gimeno, L.; Gerbedoen, J.-C.; Viard, R.; Soltani, A.; Mortet, V.; Preobrazhensky, V.; Merlen, A.; Pernod, P.

    2015-12-01

    A linear array of microscale thermal anemometers has been designed, fabricated and characterized. The sensitive element consists of a self-compensated-stress multilayer (Ni/W) patterned to form a wire with length, width, and thickness close to 200 μm, 5 μm and 2 μm respectively. The wire is deposited and supported by prongs made of nano-crystalline diamond (NCD) of about 2 μm in thickness. Due to its high Young’s modulus, NCD allows a very high mechanical toughness without the need for thicker support for the hot wire. Also, depending on grain size, the NCD is able to present thermal conductivity smaller than 10 W mK-1, providing good thermal insulation from the substrate and less conductive end losses to the prongs. The sensor was characterized experimentally. Its electrical and thermal properties were obtained first in the absence of fluid flow. The results confirm the effectiveness of thermal insulation and the mechanical robustness of the structure. The fluidic characterizations were performed and analysed in the case of an airflow with velocities of up to 30 m s-1.

  6. The Microstructure Evolution and Processing Map of Ni-18.3Cr-6.4Co-5.9W-4Mo Superalloy During Hot Deformation

    NASA Astrophysics Data System (ADS)

    Qin, Shengxue; Liu, Jie; Zhang, Hongbin; Zhang, Kaifeng

    2016-06-01

    The processing map and microstructure evolution of Ni-18.3Cr-6.4Co-5.9W-4Mo superalloy were investigated in the temperature range of 1010-1160 °C and strain rate range of 0.001-1 s-1 by means of hot compression tests. According to the processing map, the optimum processing parameters were located in the temperature range of 1100-1160 °C and strain rate range of 0.01-0.3 s-1. The carbides in the alloy contributed to form a fine grain microstructure. In addition, four different instability criteria of Prasad, Gegel, Malas, and Murty were used to predict the unstable domains in the processing map. Meanwhile, the microstructure observations revealed that the unstable domain predicted by Murty's instability criterion was very effective at high strain rate, which was the best choice for the studied alloy. Furthermore, the electron backscattered diffraction technique was used to detect the Σ3 boundaries and the adiabatic shear bands in the alloy. The results revealed that the fractions of Σ3 boundaries in the alloy deformed at 1100 °C/0.01 s-1 and 1160 °C/0.1 s-1 reached about 25 and 27%, respectively. Meanwhile, the fraction of low-angle grain boundaries and dislocation density were relatively high in the adiabatic shear band.

  7. Hot Corrosion Behavior of Bare, Cr3C2-(NiCr) and Cr3C2-(NiCr) + 0.2wt.%Zr Coated SuperNi 718 at 900 °C

    NASA Astrophysics Data System (ADS)

    Mudgal, Deepa; Singh, Surendra; Prakash, Satya

    2015-01-01

    Corrosion in incinerators, power plants, and chemical industries are frequently encountered due to the presence of salts containing sodium, sulphur, and chlorine. To obviate this problem, bare and coated alloys were tested under environments simulating the conditions present inside incinerators and power plants. 0.2 wt.% zirconium powder was incorporated in the Cr3C2-(NiCr) coating powder. The original powder and Zr containing powder was sprayed on Superni 718 alloy by D-gun technique. The bare and coated alloys were tested under Na2SO4 + K2SO4 + NaCl + KCl and Na2SO4 + NaCl environment. The corrosion rate of specimens was monitored using weight change measurements. Characterization of the corrosion products has been done using FE-SEM/EDS and XRD techniques. Bare and coated alloys showed very good corrosion resistance under given molten salt environments. Addition of 0.2wt.%Zr in Cr3C2-25%(NiCr) coating further greatly reduced the oxidation rate as well as improved the adherence of oxide scale to the coating surface during the time of corrosion.

  8. The nonlinear unloading behavior of a typical Ni-based superalloy during hot deformation: a new elasto-viscoplastic constitutive model

    NASA Astrophysics Data System (ADS)

    Chen, Ming-Song; Lin, Y. C.; Li, Kuo-Kuo; Chen, Jian

    2016-09-01

    The nonlinear unloading behavior of a typical Ni-based superalloy is investigated by hot compressive experiments with intermediate unloading-reloading cycles. The experimental results show that there are at least four types of unloading curves. However, it is found that there is no essential difference among four types of unloading curves. The variation curves of instantaneous Young's modulus with stress for all types of unloading curves include four segments, i.e., three linear elastic segments (segments I, II, and III) and one subsequent nonlinear elastic segment (segment IV). The instantaneous Young's modulus of segments I and III is approximately equal to that of reloading process, while smaller than that of segment II. In the nonlinear elastic segment, the instantaneous Young's modulus linearly decreases with the decrease in stress. In addition, the relationship between stress and strain rate can be accurately expressed by the hyperbolic sine function. This study includes two parts. In the present part, the characters of unloading curves are discussed in detail, and a new elasto-viscoplastic constitutive model is proposed to describe the nonlinear unloading behavior based on the experimental findings. While in the latter part (Chen et al. in Appl Phys A. doi: 10.1007/s00339-016-0385-0, 2016), the effects of deformation temperature, strain rate, and pre-strain on the parameters of this new constitutive model are analyzed, and a unified elasto-viscoplastic constitutive model is proposed to predict the unloading behavior at arbitrary deformation temperature, strain rate, and pre-strain.

  9. TOPEX/El Niño Watch - Pacific Ocean Conditions are Split: Cold in East, Hot in West, July 27, 1999

    NASA Image and Video Library

    1999-08-23

    The North Pacific Ocean continues to run hot and cold, with abnormally low sea levels and cool waters in the northeastern Pacific contrasting with unusually high sea levels and warm waters in the northwestern Pacific.

  10. Dynamic behavior and microstructural evolution during moderate to high strain rate hot deformation of a Fe-Ni-Cr alloy (alloy 800H)

    NASA Astrophysics Data System (ADS)

    Cao, Yu; Di, Hongshuang; Zhang, Jiecen; Yang, Yaohua

    2015-01-01

    The objective of the study is to fundamentally understand the dynamic behavior of alloy 800H at moderate to high strain rate using hot compression tests and propose nucleation mechanism associated with dynamic crystallization (DRX). We firstly investigated the dynamic behavior of alloy 800H with industrial scale strain rates using hot compression tests and adiabatic correction was performed to correct as-measured flow curves. Secondly, a Johnson-Cook model was established by using the corrected data and could give a precise prediction of elevated temperature flow stress for the studied alloy. Finally, the nucleation mechanism of DRX grains at high strain rates was studied. The results showed that the predominant nucleation mechanism for DRX is the formation of "bulge" at parent grain boundary. Additionally, the fragmentation of original grain at low deformation temperatures and the twinning near the bulged regions at high deformation temperatures also accelerate the DRX process.

  11. Dynamical cluster-decay model for hot and rotating light-mass nuclear systems applied to the low-energy {sup 32}S+{sup 24}Mg{yields}{sup 56}Ni{sup *} reaction

    SciTech Connect

    Gupta, Raj K.; Kumar, Rajesh; Singh, Dalip; Balasubramaniam, M.; Beck, C.

    2005-01-01

    The dynamical cluster-decay model (DCM) is developed further for the decay of hot and rotating compound nuclei (China) formed in light heavy-ion reactions. The model is worked out in terms of only one parameter, namely the neck-length parameter, which is related to the total kinetic energy TKE(T) or effective Q value Q{sub eff}(T) at temperature T of the hot CN and is defined in terms of the CN binding energy and ground-state binding energies of the emitted fragments. The emission of both the light particles (LP), with A{<=}4,Z{<=}2, as well as the complex intermediate mass fragments (IMF), with 42, is considered as the dynamical collective mass motion of preformed clusters through the barrier. Within the same dynamical model treatment, the LPs are shown to have different characteristics compared to those of the IMFs. The systematic variations of the LP emission cross section {sigma}{sub LP} and IMF emission cross section {sigma}{sub IMF} calculated from the present DCM match exactly the statistical fission model predictions. A nonstatistical dynamical description is developed for the first time for emission of light particles from hot and rotating CN. The model is applied to the decay of {sup 56}Ni* formed in the {sup 32}S+{sup 24}Mg reaction at two incident energies E{sub c.m.}=51.6 and 60.5 MeV. Both the IMFs and average TKE{sup lowbar} spectra are found to compare resonably well with the experimental data, favoring asymmetric mass distributions. The LPs' emission cross section is shown to depend strongly on the type of emitted particles and their multiplicities.

  12. Hot Flashes

    MedlinePlus

    ... are due to menopause — the time when menstrual periods become irregular and eventually stop. In fact, hot flashes are the most common symptom of the menopausal transition. How often hot flashes occur varies among women ...

  13. Effects of Ultra-Fast Cooling After Hot Rolling and Intercritical Treatment on Microstructure and Cryogenic Toughness of 3.5%Ni Steel

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Liu, Zhenyu

    2017-07-01

    A novel process comprised of ultra-fast cooling after control rolling, intercritical quenching and tempering (UFC-LT) was applied to 3.5%Ni steel. In addition, quenching and tempering (QT) treatment was conducted in comparison. The present study focuses on the relationship between the microstructure and cryogenic toughness of 3.5%Ni steel. Results show that the microstructure of steel treated by UFC-LT consisted of tempered martensite, intercritical ferrite and two types of reversed austenite (RA) (needle shape and blocky). Compared to the QT sample, the UFC-LT sample's ultimate tensile strength decreased slightly, while its elongation increased from 32.3 to 35.7%, and its Charpy absorption energy at -135 °C increased from 112 to 237 J. The ductile-brittle transition temperature of UFC-LT sample was lower than that of the QT sample by 18 °C. The superior cryogenic toughness after UFC-LT compared to QT treatment can be attributed to the dissolution of cementite, approximately 3.0% increase in RA and the decrease in effective grain size.

  14. Abnormal Intermetallic Compound Evolution in Ni/Sn/Ni and Ni/Sn-9Zn/Ni Micro Solder Joints Under Thermomigration

    NASA Astrophysics Data System (ADS)

    Zhao, N.; Deng, J. F.; Zhong, Y.; Huang, M. L.; Ma, H. T.

    2017-04-01

    Interfacial reactions in Ni/Sn/Ni and Ni/Sn-9Zn/Ni micro solder joints during thermomigration (TM) have been studied by reflowing solder joints on a hot plate. Asymmetrical growth and transformation of interfacial intermetallic compounds (IMCs) were clearly observed. The growth of the Ni3Sn4 IMC in the Ni/Sn/Ni solder joints was always fast at the cold end and relatively slow at the hot end. Only asymmetrical growth of the Ni5Zn21 IMC in the Ni/Sn-9Zn/Ni solder joints occurred at the beginning because Zn was the dominant TM species; however, asymmetrical transformation of the Ni5Zn21 IMC also occurred under the combined effect of Zn depletion and Ni dissolution and migration, resulting in formation of a thin τ-phase layer at the hot end and a thick τ-phase/Ni5Zn21/τ-phase sandwich structure at the cold end. TM of Ni and Zn atoms was identified towards the cold end, being responsible for the abnormal IMC evolution. Addition of Zn was found to slow the TM-induced IMC growth and Ni dissolution.

  15. Microstructure and hot corrosion behaviors of two Co modified aluminide coatings on a Ni-based superalloy at 700 °C

    NASA Astrophysics Data System (ADS)

    Fan, Q. X.; Jiang, S. M.; Yu, H. J.; Gong, J.; Sun, C.

    2014-08-01

    Two Co modified aluminide coatings with different Co contents were prepared by pack cementation process and above-the-pack process. The hot corrosion tests of the two coatings were performed in mixed salts of 75 wt.% Na2SO4 + 25 wt.% K2SO4 and 75 wt.% Na2SO4 + 25 wt.% NaCl at 700 °C, with a simple aluminide coating as the reference coating. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) with energy dispersive X-ray spectrometer (EDS) were used to characterize the coatings and the corrosion scales. Results indicate that the addition of Co improves the hot corrosion resistance of the simple aluminide coating in the mixed sulfate salts, for the sulfide as well as its eutectic of cobalt are more stable, and possess higher melting points than those of nickel. While in the mixed salt containing chloride, the coating with medium Co content possesses the best corrosion resistance, primarily because the nitrides formed in the deposition process deteriorate the corrosion resistance of the coating with highest Co content.

  16. Hot microswimmers

    NASA Astrophysics Data System (ADS)

    Kroy, Klaus; Chakraborty, Dipanjan; Cichos, Frank

    2016-11-01

    Hot microswimmers are self-propelled Brownian particles that exploit local heating for their directed self-thermophoretic motion. We provide a pedagogical overview of the key physical mechanisms underlying this promising new technology. It covers the hydrodynamics of swimming, thermophoresis and -osmosis, hot Brownian motion, force-free steering, and dedicated experimental and simulation tools to analyze hot Brownian swimmers.

  17. Hot Flashes

    MedlinePlus

    Diseases and Conditions Hot flashes By Mayo Clinic Staff Hot flashes are sudden feelings of warmth, which are usually most intense over the ... skin may redden, as if you're blushing. Hot flashes can also cause profuse sweating and may ...

  18. Corrosion behaviour and biocompatibility of a novel Ni-free intermetallic coating growth on austenitic steel by hot dipping in an Al-12.6%Si alloy.

    PubMed

    Arenas, M A; Frutos, E; Saldaña, L; Conde, A; Labajos-Broncano, L; González-Martín, M L; González-Carrasco, J L; Vilaboa, N

    2011-04-01

    Commercial 316 LVM austenitic stainless steel samples have been coated by immersion in a bath of molten Al-12.6%Si alloy for 120 s. The coating consists of the Al(12)(Fe,Cr)(3)Si(2) intermetallic. In vitro corrosion behaviour has been evaluated in the Ringer's solution by means of potentiodynamic curves and electrochemical impedance spectroscopy. The results reveal that the coated specimens exhibit lower susceptibility to localised corrosion with respect to the substrate. XPS analysis suggests that the ennoblement of the pitting potential is due to the formation of a chromium oxyhydroxide containing passive layer. The intermetallic coating shows a good biocompatibility, as demonstrated by culturing human mesenchymal stem cells isolated from bone marrow which attached, grew and differentiated to the osteoblastic lineage to a similar extent on coated and bare steels. In summary, this study proposes a method that generates Ni-free coatings of the stainless steel with useful properties for biomedical applications.

  19. Low Temperature Creep of Hot-Extruded Near-Stoichiometric NiTi Shape Memory Alloy. Part 2; Effect of Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Noebe, R. D.

    2013-01-01

    This paper is the first report on the effect prior low temperature creep on the thermal cycling behavior of NiTi. The isothermal low temperature creep behavior of near-stoichiometric NiTi between 300 and 473 K was discussed in Part I. The effect of temperature cycling on its creep behavior is reported in the present paper (Part II). Temperature cycling tests were conducted between either 300 or 373 K and 473 K under a constant applied stress of either 250 or 350 MPa with hold times lasting at each temperature varying between 300 and 700 h. Each specimen was pre-crept either at 300 or at 473 K for several months under an identical applied stress as that used in the subsequent thermal cycling tests. Irrespective of the initial pre-crept microstructures, the specimens exhibited a considerable increase in strain with each thermal cycle so that the total strain continued to build-up to 15 to 20 percent after only 5 cycles. Creep strains were immeasurably small during the hold periods. It is demonstrated that the strains in the austenite and martensite are linearly correlated. Interestingly, the differential irrecoverable strain, in the material measured in either phase decreases with increasing number of cycles, similar to the well-known Manson-Coffin relation in low cycle fatigue. Both phases are shown to undergo strain hardening due to the development of residual stresses. Plots of true creep rate against absolute temperature showed distinct peaks and valleys during the cool-down and heat-up portions of the thermal cycles, respectively. Transformation temperatures determined from the creep data revealed that the austenitic start and finish temperatures were more sensitive to the pre-crept martensitic phase than to the pre-crept austenitic phase. The results are discussed in terms of a phenomenological model, where it is suggested that thermal cycling between the austenitic and martensitic phase temperatures or vice versa results in the deformation of the austenite and

  20. Hot electron attenuation of direct and scattered carriers across an epitaxial Schottky interface

    NASA Astrophysics Data System (ADS)

    Parui, S.; Klandermans, P. S.; Venkatesan, S.; Scheu, C.; Banerjee, T.

    2013-11-01

    Hot electron transport of direct and scattered carriers across an epitaxial NiSi2/n-Si(111) interface, for different NiSi2 thickness, is studied using ballistic electron emission microscopy (BEEM). We find the BEEM transmission for the scattered hot electrons in NiSi2 to be significantly lower than that for the direct hot electrons, for all thicknesses. Interestingly, the attenuation length of the scattered hot electrons is found to be twice as large as that of the direct hot electrons. The lower BEEM transmission for the scattered hot electrons is due to inelastic scattering of the injected hot holes while the larger attenuation length of the scattered hot electrons is a consequence of the differences in the energy distribution of the injected and scattered hot electrons and the increasing attenuation length, at lower energies, of the direct hot electrons in NiSi2.

  1. Hot electron attenuation of direct and scattered carriers across an epitaxial Schottky interface.

    PubMed

    Parui, S; Klandermans, P S; Venkatesan, S; Scheu, C; Banerjee, T

    2013-11-06

    Hot electron transport of direct and scattered carriers across an epitaxial NiSi2/n-Si(111) interface, for different NiSi2 thickness, is studied using ballistic electron emission microscopy (BEEM). We find the BEEM transmission for the scattered hot electrons in NiSi2 to be significantly lower than that for the direct hot electrons, for all thicknesses. Interestingly, the attenuation length of the scattered hot electrons is found to be twice as large as that of the direct hot electrons. The lower BEEM transmission for the scattered hot electrons is due to inelastic scattering of the injected hot holes while the larger attenuation length of the scattered hot electrons is a consequence of the differences in the energy distribution of the injected and scattered hot electrons and the increasing attenuation length, at lower energies, of the direct hot electrons in NiSi2.

  2. Influence of hot isostatic pressing on the structure and properties of an innovative low-alloy high-strength aluminum cast alloy based on the Al-Zn-Mg-Cu-Ni-Fe system

    NASA Astrophysics Data System (ADS)

    Akopyan, T. K.; Padalko, A. G.; Belov, N. A.

    2015-11-01

    Hot isostatic pressing (HIP) is applied for treatment of castings of innovative low-ally high-strength aluminum alloy, nikalin ATs6N0.5Zh based on the Al-Zn-Mg-Cu-Ni-Fe system. The influence of HIP on the structure and properties of castings is studied by means of three regimes of barometric treatment with different temperatures of isometric holding: t 1 = 505 ± 2°C, p 1 = 100 MPa, τ1 = 3 h (HIP1); t 2 = 525 ± 2°C, p 2 = 100 MPa, τ2 = 3 h (HIP2); and t 3 = 545 ± 2°C, p 3 = 100 MPa, τ3 = 3 h (HIP3). It is established that high-temperature HIP leads to actually complete elimination of porosity and additional improvement of the morphology of second phases. Improved structure after HIP provides improvement properties, especially of plasticity. In particular, after heat treatment according of regime HIP2 + T4 (T4 is natural aging), the alloy plasticity is improved by about two times in comparison with the initial state (from ~6 to 12%). While applying regime HIP3 + T6 (T6 is artificial aging for reaching the maximum strength), the plasticity has improved by more than three times in comparison with the initial state, as after treatment according to regimes HIP1 + T6 and HIP2 + T6 (from ~1.2 to ~5.0%), which are characterized by a lower HIP temperature.

  3. Preparation of in situ and ex situ reinforced Fe-10Cr-1Cu-1Ni-1Mo-2C containing NbC particles by milling and hot pressing

    NASA Astrophysics Data System (ADS)

    Li, Xiao-qiang; Li, Zi-yang; Ye, Yong-quan; Hu, Ke

    2015-02-01

    An in situ and ex situ reinforced powder metallurgy (PM) steel was prepared by the combination of high-energy ball milling and subsequent hot pressing of elemental mixed powders of Fe-10Cr-1Cu-1Ni-1Mo-2C by mass with the addition of NbC particles. A 40-h milling pretreatment makes the powder particles nearly equiaxed with an average diameter of ˜8 μm, and the ferrite grain size is refined to ˜6 nm. The sintered density reaches 99.0%-99.7% of the theoretical value when the sintering is conducted at temperatures greater than 1000°C for 30 min. In the sintered bulk specimens, the formation of an in situ M7C3 (M = Cr, Fe, Mo) phase is confirmed. M7C3 carbides with several hundred nanometers in size are uniformly distributed in the matrix. Some ultra-fine second phases of 50-200 nm form around the ex situ NbC and in situ M7C3 particles. The sintered steel exhibits an excellent combination of hardness (> Hv 500) and compressive strength (2100-2420 MPa).

  4. 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,…

  5. Substrate patterning with NiOx nanoparticles and hot-wire chemical vapour deposition of WO3x and carbon nanostructures

    NASA Astrophysics Data System (ADS)

    Houweling, Z. S.

    2011-10-01

    The first part of the thesis treats the formation of nickel catalyst nanoparticles. First, a patterning technique using colloids is employed to create ordered distributions of monodisperse nanoparticles. Second, nickel films are thermally dewetted, which produces mobile species that self-arrange in non-ordered distributions of polydisperse particles. Third, the mobility of the nickel species is successfully reduced by the addition of air during the dewetting and the use of a special anchoring layer. Thus, non-ordered distributions of self-arranged monodisperse nickel oxide nanoparticles (82±10 nm x 16±2 nm) are made. Studies on nickel thickness, dewetting time and dewetting temperature are conducted. With these particle templates, graphitic carbon nanotubes are synthesised using catalytic hot-wire chemical vapour deposition (HWCVD), demonstrating the high-temperature processability of the nanoparticles. The second part of this thesis treats the non-catalytic HWCVD of tungsten oxides (WO3-x). Resistively heated tungsten filaments exposed to an air flow at subatmospheric pressures, produce tungsten oxide vapour species, which are collected on substrates and are subsequently characterised. First, a complete study on the process conditions is conducted, whereby the effects of filament radiation, filament temperature, process gas pressure and substrate temperature, are investigated. The thus controlled growth of nanogranular smooth amorphous and crystalline WO3-x thin films is presented for the first time. Partially crystalline smooth hydrous WO3-x thin films consisting of 20 nm grains can be deposited at very high rates. The synthesis of ultrafine powders with particle sizes of about 7 nm and very high specific surface areas of 121.7±0.4 m2·g-1 at ultrahigh deposition rates of 36 µm·min-1, is presented. Using substrate heating to 600°C or more, while using air pressures of 3·10-5 mbar to 0.1 mbar, leads to pronounced crystal structures, from nanowires, to

  6. Hot microelectrodes.

    PubMed

    Baranski, Andrzej S

    2002-03-15

    Heat generation at disk microelectrodes by a high-amplitude (few volt) and high-frequency (0.1-2 GHz) alternating voltage is described. This method allows changing electrode temperature very rapidly and maintaining it well above the boiling point of solution for a very long time without any indication of boiling. The size of the hot zone in solution is determined by the radius of the electrode. There is no obvious limit in regard to the electrode size, so theoretically, by this method, it should be possible to create hot spots that are much smaller than those created with laser beams. That could lead to potential applications in medicine and biology. The heat-generating waveform does not electrically interfere with normal electroanalytical measurements. The noise level at hot microelectrodes is only slightly higher, as compared to normal microelectodes, but diffusion-controlled currents at hot microelectrodes may be up to 7 times higher, and an enhancement of kinetically controlled currents may be even larger. Hot microelectrodes can be used for end-column detection in capillary electrophoresis and for in-line or in vivo analyses. Temperature gradients at hot microelectrodes may exceed 1.5 x 10(5) K/cm, which makes them useful in studies of Soret diffusion and thermoelectric phenomena.

  7. 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."

  8. 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."

  9. 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…

  10. 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…

  11. Are 'hot spots' hot spots?

    NASA Astrophysics Data System (ADS)

    Foulger, Gillian R.

    2012-07-01

    The term 'hot spot' emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a 'normal' mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ˜200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40-50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200-300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been

  12. High Temperature Chemistry at NASA: Hot Topics

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.

    2014-01-01

    High Temperature issues in aircraft engines Hot section: Ni and Co based Superalloys Oxidation and Corrosion (Durability) at high temperatures. Thermal protection system (TPS) and RCC (Reinforced Carbon-Carbon) on the Space Shuttle Orbiter. High temperatures in other worlds: Planets close to their stars.

  13. 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.

  14. Hot corrosion resistance of nickel-chromium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.; Barrett, C. A.

    1977-01-01

    The hot corrosion resistance of nickel-chromium-aluminum alloy was examined by cyclically oxidizing sodium sulfate coated specimens in still air at 900, 1000 and 1100 C. The compositions tested were within the ternary region: Ni; Ni-50 at.% Cr; and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. Corrosion isopleths were prepared from these equations. Compositional regions with the best hot corrosion resistance were identified.

  15. Hot corrosion resistance of nickel-chromium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.; Barret, C. A.

    1977-01-01

    The hot corrosion resistance of nickel-chromium-aluminum alloys was examined by cyclically oxidizing sodium sulfate-coated specimens in still air at 900, 1000, and 1100 C. The compositions tested were within the ternary region: Ni, Ni-50 at.% Cr, and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. From these equations corrosion isopleths were prepared. Compositional regions with the best hot corrosion resistance were identified.

  16. Site Occupancy of Chrome in the Gamma Prime Phase Ni3Al: An Integrated Computational and Experimental Study (Preprint)

    DTIC Science & Technology

    2011-07-01

    sublattice site in the complex Rene-88 alloy and clearly agrees with the computational results. Ni-base superalloys find major applications in the hot ...Document contains color. 14. ABSTRACT The mechanical properties of Ni-base superalloys are strongly influenced by ordered γ’-Ni3Al precipitates...neighbor lattice sites: either in the Al, Ni, or mixed sublattice sites. 15. SUBJECT TERMS Ni-base superalloys , γ’-Ni3Al precipitates, density

  17. Solar 'hot spots' are still hot

    NASA Technical Reports Server (NTRS)

    Bai, Taeil

    1990-01-01

    Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

  18. Hot tub folliculitis

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/001460.htm Hot tub folliculitis To use the sharing features on this page, please enable JavaScript. Hot tub folliculitis is an infection of the skin around ...

  19. Modelling Hot Air Balloons.

    ERIC Educational Resources Information Center

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  20. Modelling Hot Air Balloons.

    ERIC Educational Resources Information Center

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  1. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Santella, M.L.; Alexander, D.J.

    1995-05-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for (1)high-strength castable composition for turbochargers, furnace furniture, and hot-die applications; (2) castability (fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) hot fabricability of cast ingots. All of the issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes work completed to address some of these issues during the fourth quarter of FY 1994.

  2. Creep and Toughness of Cryomilled NiAl Containing Cr

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Aikin, Beverly; Salem, Jon

    2000-01-01

    NiAl-AlN + Cr composites were produced by blending cryomilled NiAl powder with approx. 10 vol % Cr flakes. In comparison to the as-consolidated matrices, hot isostatically pressed Cr-modified materials did not demonstrate any significant improvement in toughness. Hot extruded NiAl-AlN+10.5Cr, however, possessed a toughness twice that determine for the base NiAl-AlN alloy. Measurement of the 1200 to 1400 K plastic flow properties revealed that the strength of the composites was completely controlled by the properties of the NiAl-AlN matrices. This behavior could be successfully modeled by the Rule-of-Mixtures, where load is shed from the weak Cr to the strong matrix.

  3. In situ NiTi/Nb(Ti) composite

    SciTech Connect

    Jiang, Daqiang Cui, Lishan; Jiang, Jiang; Zheng, Yanjun

    2013-12-15

    Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength.

  4. 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

  5. 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

  6. High Velocity Oxidation and Hot Corrosion Resistance of Some ODS Alloys

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    Several oxide dispersion strengthened (ODS) alloys were tested for cyclic, high velocity, oxidation, and hot corrosion resistance. These results were compared to the resistance of an advanced, NiCrAl coated superalloy. An ODS FeCrAl were identified as having sufficient oxidation and hot corrosion resistance to allow potential use in an aircraft gas turbine without coating.

  7. Hot techniques for tonsillectomy.

    PubMed

    Scott, A

    2006-11-01

    (1) Some patients experience pain and bleeding after a standard or extracapsular tonsillectomy. (2) Evidence suggests that none of the hot tonsillectomy techniques offers concurrent reductions in intra- and post-operative bleeding and pain, compared with traditional cold-steel dissection with packs or ties. (3) Little information is available on the cost effectiveness of the hot techniques. (4) Diathermy is likely to remain the most commonly practised hot tonsillectomy technique.

  8. Effects of surface chemistry on hot corrosion life

    NASA Technical Reports Server (NTRS)

    Fryxell, R. E.

    1984-01-01

    Baseline burner rig hot corrosion with Udimet 700, Rene' 80; uncoated and with RT21, Codep, or NiCoCrAlY coatings were tested. Test conditions are: 900C, hourly thermal cycling, 0.5 ppm sodium as NaCl in the gas stream, velocity 0.3 Mach. The uncoated alloys exhibited substantial typical sulfidation in the range of 140 to 170 hours. The aluminide coatings show initial visual evidence of hot corrosion at about 400 hours, however, there is no such visual evidence for the NiCoCrAlY coatings. The turbine components show sulfidation. The extent of this distress appeared to be inversely related to the average length of mission which may, reflect greater percentage of operating time near ground level or greater percentage of operation time at takeoff conditions (higher temperatures). In some cases, however, the location of maximum distress did not exhibit the structural features of hot corrosion.

  9. 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)

  10. 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…

  11. 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…

  12. 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)

  13. 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

  14. What Is Hot Yoga (Bikram)?

    MedlinePlus

    Healthy Lifestyle Consumer health What is hot yoga? Answers from Edward R. Laskowski, M.D. Hot yoga is ... 30, 2015 Original article: http://www.mayoclinic.org/healthy-lifestyle/consumer-health/expert-answers/hot-yoga/faq-20058057 . ...

  15. Ni-Si Alloys for the S-I Reactor-Hydrogen Production Process Interface

    SciTech Connect

    Joseph W. Newkirk; Richard K. Brow

    2010-01-21

    The overall goal of this project was to develop Ni-Si alloys for use in vessels to contain hot, pressurized sulfuric acid. The application was to be in the decomposition loop of the thermochemical cycle for production of hydrogen.

  16. Environmentally Assisted Cracking of Commercial Ni-Cr-Mo Alloys - A Review

    SciTech Connect

    Rebak, R B

    2004-11-09

    Nickel-Chromium-Molybdenum alloys (Ni-Cr-Mo) are highly resistant to general corrosion, localized corrosion and environmentally assisted cracking (EAC). Cr acts as a beneficial element under oxidizing acidic conditions and Mo under reducing conditions. All three elements (Ni, Cr and Mo) act synergistically to provide resistance to EAC in environments such as hot concentrated chloride solutions. Ni-Cr-Mo alloys may suffer EAC in environments such as hot caustic solutions, hot wet hydrofluoric acid (HF) solutions and in super critical water oxidation (SCWO) applications. Not all the Ni-Cr-Mo alloys have the same susceptibility to cracking in the mentioned environments. Most of the available data regarding EAC is for the oldest Ni-Cr-Mo alloys such as N10276 and N06625.

  17. Hot ice computer

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    2009-12-01

    We experimentally demonstrate that supersaturated solution of sodium acetate, commonly called ‘hot ice’, is a massively-parallel unconventional computer. In the hot ice computer data are represented by a spatial configuration of crystallization induction sites and physical obstacles immersed in the experimental container. Computation is implemented by propagation and interaction of growing crystals initiated at the data-sites. We discuss experimental prototypes of hot ice processors which compute planar Voronoi diagram, shortest collision-free paths and implement AND and OR logical gates.

  18. Smokin Hot Galaxy animation

    NASA Image and Video Library

    2006-03-16

    This infrared image from NASA Spitzer Space Telescope shows a galaxy that appears to be sizzling hot, with huge plumes of smoke swirling around it. The galaxy is known as Messier 82 or the Cigar galaxy.

  19. Saturn's Hot Plasma Explosions

    NASA Image and Video Library

    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 ...

  20. Modelling hot air balloons

    NASA Astrophysics Data System (ADS)

    Brimicombe, N. W.

    1991-07-01

    Hot air balloons can be modelled in a number of different ways. The most satisfactory, but least useful model is at a microscopic level. Macroscopic models are easier to use but can be very misleading.

  1. Saturn Hot Plasma Explosions

    NASA Image and Video Library

    2010-12-14

    This frame from an animation based on data obtained by NASA Cassini spacecraft shows how the explosions of hot plasma on the night side orange and white periodically inflate Saturn magnetic field white lines.

  2. In hot water, again

    NASA Astrophysics Data System (ADS)

    Basden, Alastair; Watkins, Sheila

    2009-10-01

    Regarding Norman Willcox's letter about the problems of using solar panels for domestic heating (August p21), I also have thermal solar panels installed. However, contrary to his disappointing experience, I have found that they provide my family with a useful amount of hot water. In our system, the solar energy is used to heat a store of water, which has no other source of heat. Mains-pressure cold water passes through this store via a heat exchanger, removing heat from it and warming up. If the water becomes warm enough, an unpowered thermostatic valve allows it to go straight to the hot taps (mixing it with cold if it is too hot). However, if it is not hot enough, then the water is directed first through our previously installed gaspowered combination boiler and then to the taps.

  3. Hot ammonia in Orion

    SciTech Connect

    Morris, M.; Palmer, P.; Zuckerman, B.

    1980-04-01

    Ten inversion lines from nonmetastable rotational levels of NH/sub 3/ have been detected in the Kleinmann-Low (KL) nebula in Orion. Six of these lines were previoulsy undetected. The emission arises from levels which have energies up to 1150 K above the ground state, indicating that the NH/sub 3/ is immersed in a hot, dense medium. Three well-defined kinematical components within KL are evident in emission from NH/sub 3/ and other molecules. The emission from hot NH/sub 3/ is dominated by the component having V/sub LSR/=5.2 km s/sup -1/ and ..delta..V =10--12 km s/sup -1/. A non-LTE analysis of NH/sub 3/ emission from this ''hot core'' component reveals that the minimum particle density in this source is approx.5 x 10 cm/sup -3/, and that the kinetic temperature is > or approx. =220 K. The diameter of the hot core source is probably within a factor of 2 to 6'' (5 x 10/sup 16/ cm). The hot core is undoubtedly associated with one of the compact infrared sources in KL, and we suggest on the basis of position and velocity coincidences that it is IRc2. The hot core appears to contain about one Jeans mass at the inferred temperature and density. We therefore suggest that this object is a very young protostar which is still in the throes of its initial collapse.

  4. 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.

  5. Development and High Temperature Property Evaluation of Ni-Co-Cr-Al Composite Electroforms

    NASA Astrophysics Data System (ADS)

    Srivastava, Meenu; Siju; Balaraju, J. N.; Ravisankar, B.

    2015-05-01

    Ni-Co-Cr-Al composite electroforms were developed with cobalt content of 10 and 40 wt.%. Cr and Al nano-particles were suspended in sulphamate electrolyte and co-deposited in the Ni-Co matrices. The surface morphology was investigated using field emission scanning electron microscope and the composition analyzed by energy-dispersive x-ray analysis. The oxidation resistance of the electroforms was studied from 600 to 1000 °C. The weight gain of Ni-10 wt.%Co-Cr-Al was less (better oxidation resistance) compared to Ni-Cr-Al and Ni-40 wt.%Co-Cr-Al. The x-ray diffraction studies revealed that the oxidation product formed on the surface of Ni-Cr-Al and Ni-10 wt.%Co-Cr-Al consisted of NiO and Al2O3, while Ni-40 wt.%Co-Cr-Al comprised oxides such as NiCo2O4, CrO3, CoO, NiO, and Al2O3. The hot corrosion behavior was investigated in 75%Na2SO4 + 25%NaCl environment at 800 °C. It was found that the hot corrosion resistance of the composite coating improved with increase in cobalt content. The probable composition suitable for high-temperature applications was found to be Ni-10 wt.%Co-Cr-Al.

  6. Low temperature hot corrosion

    NASA Technical Reports Server (NTRS)

    Chiang, K. T.; Pettit, F. S.; Meier, G. H.

    1983-01-01

    The reaction of Co-Cr, Ni-Cr, Co-Cr-Al, and Ni-Cr-Al alloys with Na2SO4 in the presence of SO3 at temperatures between 700 and 750 C leads to the formation of liquid CoSO4-Na2SO4 or NiSO4-Na2SO4 deposits on the alloy surface. The formation of Cr2O3 and/or Al2O3 below this deposit results in a locally low P(O2) and a higher P(S2) and P(SO2). It is noted that these conditions can prevent protective oxide formation either by sulfide formation in the alloy, which localizes the Cr and/or Al in discrete particles, or by acid fluxing involving a reaction between Al2O3 or Cr2O3 and SO2 to form a salt-soluble species and subsequent reprecipitation as porous oxides in regions of higher P(O2). These processes may occur simultaneously, although a given alloy generally exhibits features of predominantly one type. Here, the Ni-Cr and Ni-Cr-Al alloys, and to some extent the Co-Cr alloys, exhibit features indicative of the sulfidation mechanism, whereas the morphology for the Co-Cr-Al alloy is more consistent with a predominant acid fluxing mechanism.

  7. The hot list strategy.

    SciTech Connect

    Wos, L.; Pieper, G. W.; Mathematics and Computer Science

    1999-01-01

    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, I formulated and feature in this article the hot list strategy. The hot list strategy asks the researcher to choose, usually from among the input statements characterizing the problem under study, one or more statements that are conjectured to play a key role for assignment completion. The chosen statements--conjectured to merit revisiting, again and again--are placed in an input list of statements, called the hot list. When an automated reasoning program has decided to retain a new conclusion C--before any other statement 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, I focus 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. I also

  8. HotRegion: a database of predicted hot spot clusters

    PubMed Central

    Cukuroglu, Engin; Keskin, Ozlem

    2012-01-01

    Hot spots are energetically important residues at protein interfaces and they are not randomly distributed across the interface but rather clustered. These clustered hot spots form hot regions. Hot regions are important for the stability of protein complexes, as well as providing specificity to binding sites. We propose a database called HotRegion, which provides the hot region information of the interfaces by using predicted hot spot residues, and structural properties of these interface residues such as pair potentials of interface residues, accessible surface area (ASA) and relative ASA values of interface residues of both monomer and complex forms of proteins. Also, the 3D visualization of the interface and interactions among hot spot residues are provided. HotRegion is accessible at http://prism.ccbb.ku.edu.tr/hotregion. PMID:22080558

  9. High temperature dispersion strengthening of NiAl

    NASA Technical Reports Server (NTRS)

    Sherman, M.; Vedula, K.

    1986-01-01

    A potential high temperature strengthening mechanism for alloys based on the intermetallic compound NiAl was investigated. This study forms part of an overall program at NASA Lewis Research Center for exploring the potential of alloys based on NiAl for high temperature applications. An alloy containing 2.26 at% Nb and produced by hot extrusion of blended powders was examined in detail using optical and electron microscopy. Interdiffusion between the blended Nb and NiAl powders results in the formation of intermediate phases. A fine dispersion of precipitates of a hexagonal, ordered NiAlNb phases in a matrix of NiAl can be produced and this results in strengthening of the alloy by interfering with dislocation motion at high temperature. These precipitates are, however, found to coarsen during the high temperature (1300 K) deformation at slow strain rates and this may impose some limitatioins on the use of this strengthening mechanism.

  10. 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.

  11. 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.

  12. 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.

  13. Evaluation model of susceptibility to Cu hot shortness of Cu-containing LC steel

    NASA Astrophysics Data System (ADS)

    Jiang, Yinghua; Xie, Chunqian

    2017-06-01

    It is well known that copper causes the hot shortness problem when in the scrap based steelmaking process. Hot shortness occurs because of selective oxidation of the iron whereby the more noble copper is enriched at the steel-oxide interface and embrittlement take places during hot working. In this paper, in order to control the Cu hot shortness, the evaluation model of susceptibility to Cu hot shortness was investigated. We found that Cu hot shortness susceptibility is related to the oxidation rate, the copper equivalence and the scale-steel interface length ratio. Also, it is founded to exist a fairly nice correlation between the oxidation rate and other factors such as chemistry elements, oxidation conditions, especially the Ni content.

  14. 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…

  15. 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.

  16. 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…

  17. 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.

  18. Geodynamics: Hot mantle rising

    NASA Astrophysics Data System (ADS)

    Shorttle, Oliver

    2017-06-01

    The long-term cooling of Earth's mantle is recorded in the declining temperature and volume of its volcanic outpourings over time. However, analyses of 89-million-year-old lavas from Costa Rica suggest that extremely hot mantle still lurks below.

  19. Neptune Hot South Pole

    NASA Image and Video Library

    2007-09-18

    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 Sept. 1 and 2, 2006.

  20. 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…

  1. 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…

  2. 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.

  3. INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 1

    NASA Technical Reports Server (NTRS)

    2003-01-01

    INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 16 (FOAM CORE) / CARBON REINFORCED CYANOESTER (CERAMIC MATRIX COMPOSITE - CMC) HOT STRUCTURE, PANEL 884-1: SAMPLE 1

  4. INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 1

    NASA Technical Reports Server (NTRS)

    2003-01-01

    INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 16 (FOAM CORE) / CARBON REINFORCED CYANOESTER (CERAMIC MATRIX COMPOSITE - CMC) HOT STRUCTURE, PANEL 884-1: SAMPLE 3

  5. Hot Corrosion Behavior of HVOF Sprayed Coatings on ASTM SA213-T11 Steel

    NASA Astrophysics Data System (ADS)

    Sidhu, H. S.; Sidhu, B. S.; Prakash, S.

    2007-09-01

    Cr3C2-NiCr, NiCr, WC-Co and Stellite-6 alloy coatings were sprayed on ASTM SA213-T11 steel using the HVOF process. Liquid petroleum gas was used as the fuel gas. Hot corrosion studies were conducted on the uncoated as well as HVOF sprayed specimens after exposure to molten salt at 900 °C under cyclic conditions. The thermo-gravimetric technique was used to establish the kinetics of corrosion. XRD, SEM/EDAX and EPMA techniques were used to analyze the corrosion products. All these overlay coatings showed a better resistance to hot corrosion as compared to that of uncoated steel. NiCr Coating was found to be most protective followed by the Cr3C2-NiCr coating. WC-Co coating was least effective to protect the substrate steel. It is concluded that the formation of Cr2O3, NiO, NiCr2O4, and CoO in the coatings may contribute to the development of a better hot-corrosion resistance. The uncoated steel suffered corrosion in the form of intense spalling and peeling of the scale, which may be due to the formation of unprotective Fe2O3 oxide scale.

  6. Homing in on Hot Dogs

    NASA Image and Video Library

    2012-08-29

    This image is a portion of the all-sky survey from NASA WISE. It highlights the first of about 1,000 hot DOGs found by the mission magenta circle. Hot DOGs are hot dust-obscured galaxies and are among the most powerful galaxies known.

  7. Evaporation of hot jupiters and hot neptunes

    NASA Astrophysics Data System (ADS)

    Ehrenreich, D.

    2011-02-01

    Among the nearly five hundred extra-solar planets known, almost 30% orbit closer than 0.1 AU from their parent star. We will review the observations and the corresponding models of the evaporation of these `hot jupiters'. The observations started with the discovery made with HST that the planet orbiting HD 209458 has an extended atmosphere of escaping hydrogen. Subsequent observations obtained with HST/STIS and HST/ACS confirm the escape of the gas. Even more, oxygen and carbon have been shown to be present at very high altitude in the upper atmosphere. Observations of other targets like HD 189733 and WASP-12 show that evaporation is a general phenomenon which could contribute to the evolution of planets orbiting close to their parent stars. To interpret these observations, we developed models to quantify the escape rate from the measured occultation depths. Numerous models have also been published to investigate mechanisms which can lead to the estimated escape rate. In general, the high temperature of the upper atmosphere heated by the far and extreme UV combined with the tidal forces allow a very efficient evaporation of the upper atmosphere. We will review the different models and their implications.

  8. Hot workability of magnesium alloys

    NASA Astrophysics Data System (ADS)

    Mwembela, Aaron Absalom

    reduced grain sizes and higher misorientation. Dynamic recrystallization does not become general as in Cu or Ni, thus it does not markedly raise the ductility. Retention of the hot worked substructure, or the refined grains, improves the strength and ductility of the product.

  9. 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.

  10. 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

  11. The hot chocolate effect

    NASA Astrophysics Data System (ADS)

    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 10% accuracy of the experiments.

  12. 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.

  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'' 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.

  15. HOT infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Martyniuk, P.; Rogalski, A.

    2013-06-01

    At present, uncooled thermal detector focal plane arrays are successfully used in staring thermal imagers. However, the performance of thermal detectors is modest, they suffer from slow response and they are not very useful in applications requiring multispectral detection. Infrared (IR) photon detectors are typically operated at cryogenic temperatures to decrease the noise of the detector arising from various mechanisms associated with the narrow band gap. There are considerable efforts to decrease system cost, size, weight, and power consumption to increase the operating temperature in so-called high-operating-temperature (HOT) detectors. Initial efforts were concentrated on photoconductors and photoelectromagnetic detectors. Next, several ways to achieve HOT detector operation have been elaborated including non-equilibrium detector design with Auger suppression and optical immersion. Recently, a new strategies used to achieve HOT detectors include barrier structures such as nBn, material improvement to lower generation-recombination leakage mechanisms, alternate materials such as superlattices and cascade infrared devices. Another method to reduce detector's dark current is reducing volume of detector material via a concept of photon trapping detector. In this paper, a number of concepts to improve performance of photon detectors operating at near room temperature are presented. Mostly three types of detector materials are considered — HgCdTe and InAsSb ternary alloys, and type-II InAs/GaSb superlattice. Recently, advanced heterojunction photovoltaic detectors have been developed. Novel HOT detector designs, so called interband cascade infrared detectors, have emerged as competitors of HgCdTe photodetectors.

  16. The "hot" patella.

    PubMed

    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.

  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. Spectra of Hot Cores

    NASA Astrophysics Data System (ADS)

    Chakrabarti, S.; McKee, C. F.

    2003-12-01

    The turbulent core model for massive star formation (McKee & Tan 2002) generalizes the standard isothermal collapse model for low-mass stars to include turbulent pressure support. This model predicts reasonable massive star formation times of order 105 years, which is short enough to overcome the radiation pressure of the newly formed star. We calculate the millimeter and infrared spectrum predicted by the turbulent core model and compare with observations of several hot molecular cores. We consider spherically symmetric dust envelopes and use DUSTY, a 1-D radiative transfer code (Ivezic, Nenkova, Elitzur 1997), to numerically calculate the SEDs of these hot cores. We also analytically calculate the spectra in the asymptotic regions of low and high frequency and join these asymptotic forms smoothly by a fitting function that minimizes the relative error between the analytic and numerical spectra. Thus, we are able to express the functional dependence of the spectra of hot cores in terms of the dynamical variables of any given collapse model. This approach allows us to use observed SEDs as a diagnostic tool in inferring physical conditions in these cores.

  19. 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.

  20. Depomedroxyprogesterone acetate for hot flashes.

    PubMed

    Barton, Debra; Loprinzi, Charles; Quella, Susan; Sloan, Jeff; Pruthi, Sandya; Novotny, Paul

    2002-12-01

    To evaluate the efficacy of a long-acting preparation of medroxyprogesterone acetate for hot flash management, 3 men receiving androgen ablation therapy for prostate cancer and 15 women with a history of breast cancer were treated as part of clinical practice with three biweekly intramuscular injections of 500 mg depomedroxyprogesterone. A review of hot flash diaries and patient charts were completed to evaluate the effectiveness and tolerability of these injections for managing hot flashes. Treatment was associated with an approximate 90% decrease in hot flashes (95% CI 82-97%). Daily hot flash frequency decreased from a mean of 10.9 on the first day of treatment (95% CI 8.0-13.8 hot flashes per day) to a mean of 1.1 hot flashes 6 weeks later (95% CI 0.5-1.8 hot flashes) and to a mean of 0.7 hot flashes 12 weeks following therapy initiation (95% CI 0.1-1.2). Improvement in the hot flashes remained for months after discontinuing the injections in many patients. Reported side effects were minimal. This experience suggests that treatment with depomedroxyprogesterone may be an effective and well-tolerated option for the treatment of hot flashes.

  1. 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

  2. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Viswanathan, S.; Santella, M.L.

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, and wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.

  3. Particle entropy and depairing in hot nuclei

    NASA Astrophysics Data System (ADS)

    Saranya, J. Dhivya; Boomadevi, N.; Rajasekaran, T. R.

    2016-11-01

    The nuclear level densities and single particle entropies are predicted for nuclei in the mass region 50 < A < 74 within a framework of statistical theory of hot nuclei method. In this method, particle-number and energy conservation as well as nuclear pairing correlations are included in the partition function of grand canonical ensemble. The suppression of pairing correlations is distinctly noticed in temperature dependence of entropies between the critical temperatures TC ≈ 0.7 MeV and TC ≈ 1.0 MeV for 50,51V, 61,62Ni and 73,74Ge isotopes of the elements. These structural thermodynamic entropies are interpreted as a remarkable signature of the superfluid to normal phase transition connected to the vanishing of pairing gap. The calculated level densities are compared with recent experimental values. In addition, the single particle entropy of intermediate-mass nuclei is depicted as half of the entropy of mid-shell nuclei in the rare-earth region. As a consequence, the N = 28 shell closure of 51V carries low entropy at low excitation energy presents an interesting analogy to the Z = 28 shell closure of 61Ni. Merely, in the case of odd-even 73Ge has higher entropy than the even-even 74Ge nucleus.

  4. Analysis of NiAlTa precipitates in beta-NiAl + 2 at. pct Ta alloy

    NASA Technical Reports Server (NTRS)

    Pathare, V.; Michal, G. M.; Vedula, K.; Nathal, M. V.

    1987-01-01

    Results are reported from experiments performed to identify the precipitates, and their orientation in the matrix, in a beta-NiAl alloy containing 2 at. pct. Ta after undergoing creep test at 1300 K. Test specimens formed by extruding hot powders were compressed at 1300 K for about 50 hr at a strain rate averaging 6/1 million per sec. The specimens were then thinned and examined under an electron microscope and by X-ray diffractometry. An intermetallic NiAlTa compound with a hexagonal Cl4 structure appeared as second phase precipitates in the samples, exhibiting plate-like shapes and a habit plane close to (012). The prism planes of the hexagonal NiAlTa precipitates paralleled the closest packed planes in the cubic beta-NiAl matrix.

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

    PubMed

    Bonath, E

    1990-10-05

    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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Configurable hot spot fixing system

    NASA Astrophysics Data System (ADS)

    Kajiwara, Masanari; Kobayashi, Sachiko; Mashita, Hiromitsu; Aburada, Ryota; Furuta, Nozomu; Kotani, Toshiya

    2014-03-01

    Hot spot fixing (HSF) method has been used to fix many hot spots automatically. However, conventional HSF based on a biasing based modification is difficult to fix many hot spots under a low-k1 lithography condition. In this paper we proposed a new HSF, called configurable hotspot fixing system. The HSF has two major concepts. One is a new function to utilize vacant space around a hot spot by adding new patterns or extending line end edges around the hot spot. The other is to evaluate many candidates at a time generated by the new functions. We confirmed the proposed HSF improves 73% on the number of fixing hot spots and reduces total fixing time by 50% on a device layout equivalent to 28nm-node. The result shows the proposed HSF is effective for layouts under the low-k1 lithography condition.

  12. 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.

  13. 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

  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. Investigation of vanadium and hot-corrosion resistance of chromium- and silicon-base coating systems

    SciTech Connect

    Barkalow, R.H.; Kahn, A.S.

    1981-04-01

    This program evaluated turbine coating materials for resisting hot corrosion and ash erosion effects due to V, S, and alkali metals in residual oils, and coal-derived fuels. Furnace and burner rig tests were conducted to evaluate the performance of NiCrSi alloys, NiCrSi alloys containing additives, Cr-base alloys, and Si-34Cr-23Ta in Na/sub 2/SO/sub 4/, V/sub 2/O/sub 5/ and mixed salt hot corrosion. CoCrAlY, Co-40Cr-8Si, and Cr-20Ni-5Mn-5Si were also evaluated. Tests in gaseous environments containing SO/sub 3/ are planned. 8 figures. (DLC)

  16. 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.

  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. Infrared hot carrier diode mixer.

    PubMed

    Aukerman, L W; Erler, J W

    1977-11-01

    Detection of a 54.3-GHz beatnote at 10.6 microm has been observed with a hot carrier diode mixer. The diode consists of a "cat whisker" antenna, which forms an ohmic point contact to n-InAs. The mechanism of this room-temperature detector is described as the "thermoelectric effect" of hot carriers.

  19. 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.

  20. NiAl-Base Composite Containing High Volume Fraction of AIN Particulate for Advanced Engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Whittenberger, J. D.; Lowell, C. E.; Garg, A.

    1995-01-01

    Cryomilling of prealloyed NiAl containing 53 at. % AJ was carried out to achieve high nitrogen levels. The consolidation of cryomilled powder by extrusion or hot pressing/ hot isostatic pressing resulted in a fully dense NiAl-base composite containing 30 vol. % of inhomogeneously distributed, nanosized AIN particulate. The NiAl-30AIN composite exhibited the highest compression yield strengths at all temperatures between 300 and 1300 K as compared with other compositions of NiAl-AIN composite. The NiAl-30AIN specimens tested under compressive creep loading between 1300 and 1500 K also exhibited the highest creep resistance with very little surface oxidation indicating also their superior elevated temperature oxidation resistance. In the high stress exponent regime, the strength is proportional to the square root of the AIN content and in the low stress exponent regime, the influence of AIN content on strength appears to be less dramatic. The specific creep strength of this material at 1300 K is superior to a first generation Ni-base single crystal superalloy. The improvements in elevated temperature creep strength and oxidation resistance have been achieved without sacrificing the room temperature fracture toughness of the NiAl-base material. Based on its attractive combination of properties, the NiAl-30AIN composite is a potential candidate for advanced engine applications,

  1. Microstructure, Mechanical and Wear Behaviors of Hot-Pressed Copper-Nickel-Based Materials for Diamond Cutting Tools

    NASA Astrophysics Data System (ADS)

    Miranda, G.; Ferreira, P.; Buciumeanu, M.; Cabral, A.; Fredel, M.; Silva, F. S.; Henriques, B.

    2017-08-01

    The current trend to replace cobalt in diamond cutting tools (DCT) for stone cutting has motivated the study of alternative materials for this end. The present study characterizes several copper-nickel-based materials (Cu-Ni; Cu-Ni-10Sn, Cu-Ni-15Sn, Cu-Ni-Sn-2WC and Cu-Ni-Sn-10WC) for using as matrix material for diamond cutting tools for stone. Copper-nickel-based materials were produced by hot pressing, at a temperature of 850 °C during 15 min and under an applied pressure of 50 MPa. The mechanical properties were evaluated though the shear strength and hardness values. The microstructures and fracture surfaces were analyzed by SEM. The wear behavior of all specimens was assessed using a reciprocating ball-on-plate tribometer. The hot pressing produced compacts with good densification. Sn and WC promoted enhanced mechanical properties and wear performance to Cu-Ni alloys. Cu-Ni-10Sn and Cu-Ni-10Sn-2WC displayed the best compromise between mechanical and wear performance.

  2. 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.

  3. 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

  4. 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

  5. Magnetic properties of Ni and Cu-Ni nanoparticles

    NASA Astrophysics Data System (ADS)

    Ganga, B. G.; Santhosh, P. N.; Thomas, P. John

    2012-06-01

    Ni and Cu-Ni nanoparticles were prepared by solution phase method and crystal phase was identified by XRD. SEM and EDX were used to analyze morphology and elemental composition of nanoparticles. Magnetic measurements indicate that Ni nanoparticles are superparamagnetic at room temperature and blocking temperature is around 103 K. Ferromagnetism is observed in the case of Cu-Ni nanoparticles with decrease in magnetization compared to Ni nanoparticles.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Composite hot drape forming

    NASA Astrophysics Data System (ADS)

    Ott, Thomas

    1994-02-01

    This program was initiated to replace labor-intensive ply-by-ply layup of composite I-beam posts and angle stiffeners used in the Space Station Freedom (SSF) rack structure. Hot drape forming (HDF) has been successfully implemented by BCAG for 777 composite I-stringers and by Bell Helicopter/Textron for the V-22 I-stingers. The two companies utilize two vastly different approaches to the I-beam fabrication process. A drape down process is used by Bell Helicopter where the compacted ply charge is placed on top of a forming mandrel and heated. When the heated ply charge reached a set temperature, vacuum pressure is applied and the plies are formed over the mandrel. The BCAG 777 process utilizes an inverted forming process where the ply stack is placed on a forming table and the mandrel is inverted and placed upon the ply stack. A heating and vacuum bladder underneath the ply stack form the play stack up onto the mandrels after reaching the temperature setpoint. Both methods have their advantages, but the drape down process was selected for SSF because it was more versatile and could be fabricated from readily available components.

  11. 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.

  12. 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.

  13. 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.

  14. HOT STARS WITH HOT JUPITERS HAVE HIGH OBLIQUITIES

    SciTech Connect

    Winn, Joshua N.; Albrecht, Simon; Fabrycky, Daniel; Johnson, John Asher

    2010-08-01

    We show that stars with transiting planets for which the stellar obliquity is large are preferentially hot (T{sub eff} > 6250 K). This could explain why small obliquities were observed in the earliest measurements, which focused on relatively cool stars drawn from Doppler surveys, as opposed to hotter stars that emerged more recently from transit surveys. The observed trend could be due to differences in planet formation and migration around stars of varying mass. Alternatively, we speculate that hot-Jupiter systems begin with a wide range of obliquities, but the photospheres of cool stars realign with the orbits due to tidal dissipation in their convective zones, while hot stars cannot realign because of their thinner convective zones. This in turn would suggest that hot Jupiters originate from few-body gravitational dynamics and that disk migration plays at most a supporting role.

  15. Hot Electron Emission in Semiconductors.

    DTIC Science & Technology

    2014-09-26

    Second Interim Report Hot Electron Emission in Semiconductors Jan. 85 - June 85 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) 6. CONTRACT OR GRANT NUMBER(a...KEY WORDS (Continue on reverse side Jf necessary and identify by block number) " -novel tunable FIR sources) • hot electron emission in GaAs/GaAlAs...heterostructures)" -,/ " streaming of hot carriers in crossed electric and magnetic fields ABST’AACr C-rrhmus- m .wr. efe it rewo-- .rv d identify by

  16. Hot melt adhesive attachment pad

    NASA Technical Reports Server (NTRS)

    Fox, R. L.; Frizzill, A. W.; Little, B. D.; Progar, D. J.; Coultrip, R. H.; Couch, R. H.; Gleason, J. R.; Stein, B. A.; Buckley, J. D.; St.clair, T. L. (Inventor)

    1984-01-01

    A hot melt adhesive attachment pad for releasably securing distinct elements together is described which is particularly useful in the construction industry or a spatial vacuum environment. The attachment pad consists primarily of a cloth selectively impregnated with a charge of hot melt adhesive, a thermo-foil heater, and a thermo-cooler. These components are securely mounted in a mounting assembly. In operation, the operator activates the heating cycle transforming the hot melt adhesive to a substantially liquid state, positions the pad against the attachment surface, and activates the cooling cycle solidifying the adhesive and forming a strong, releasable bond.

  17. Hot Corrosion Resistance and Mechanical Behavior of Atmospheric Plasma Sprayed Conventional and Nanostructured Zirconia Coatings

    NASA Astrophysics Data System (ADS)

    Saremi, Mohsen; Keyvani, Ahmad; Heydarzadeh Sohi, Mahmoud

    Conventional and nanostructured zirconia coatings were deposited on In-738 Ni super alloy by atmospheric plasma spray technique. The hot corrosion resistance of the coatings was measured at 1050°C using an atmospheric electrical furnace and a fused mixture of vanadium pent oxide and sodium sulfate respectively. According to the experimental results nanostructured coatings showed a better hot corrosion resistance than conventional ones. The improved hot corrosion resistance could be explained by the change of structure to a dense and more packed structure in the nanocoating. The evaluation of mechanical properties by nano indentation method showed the hardness (H) and elastic modulus (E) of the YSZ coating increased substantially after hot corrosion.

  18. The rolling texture of 18% Ni-350 maraging steel

    SciTech Connect

    Haq, A. ul; Khan, A.Q. )

    1993-02-01

    Texture development in hot rolled sheet and hot forged tube of 18% Ni-350 maraging steel has been studied after various degrees of cold deformation and flow turning, respectively. Hot rolled sheet exhibited considerable mechanical anisotropy. Weak texture development was observed following flow turning compared to cold deformation. Above 80% deformation, an increase in work hardening was accompanied by an increase in the orientation density of the texture component (001)[110]. Deformation of 97% leads to the development of the texture component (111)[110], with the highest orientation density 10.3 times random and a constant orientation density of 9 times random along [var phi][sub 1] at [phi] = 55[degree] and [var phi][sub 2] = 45[degree]. This texture was correlated with the appearance of shear bands in the microstructure.

  19. Hot Corrosion of Nickel-Base Alloys in Biomass-Derived Fuel Simulated Atmosphere

    SciTech Connect

    Leyens, C.; Pint, B.A.; Wright, I.G.

    1999-02-28

    Biomass fuels are considered to be a promising renewable source of energy. However, impurities present in the fuel may cause corrosion problems with the materials used in the hot sections of gas turbines and only limited data are available so far. As part of the Advanced Turbine Systems Program initiated by the U.S. Department of Energy, the present study provides initial data on the hot corrosion resistance of different nickel-base alloys against sodium sulfate-induced corrosion as a baseline, and against salt compositions simulating biomass-derived fuel deposits. Single crystal nickel-superalloy Rene N5, a cast NiCrAlY alloy, a NiCoCrAlY alloy representing industrially used overlay compositions, and a model {beta}NiAl+Hf alloy were tested in 1h thermal cycles at 950 C with different salt coatings deposited onto the surfaces. Whereas the NiCoCrAlY alloy exhibited reasonable resistance against pure sodium sulfate deposits, the NiCrAiY alloy and Rene N5 were attacked severely. Although considered to be an ideal alumina former in air and oxygen at higher temperatures, {beta}NiAl+Hf also suffered from rapid corrosion attack at 950 C when coated with sodium sulfate. The higher level of potassium present in biomass fuels compared with conventional fuels was addressed by testing a NiCoCrAlY alloy coated with salts of different K/Na atomic ratios. Starting at zero Na, the corrosion rate increased considerably when sodium was added to potassium sulfate. In an intermediate region the corrosion rate was initially insensitive to the K/Na ratio but accelerated when very Na-rich compositions were deposited. The key driver for corrosion of the NiCoCrAlY alloy was sodium sulfate rather than potassium sulfate, and no simple additive or synergistic effect of combining sodium and potassium was found.

  20. Adjustment of temperature coefficient of resistance in NiCr/CuNi(Mn)/NiCr films

    NASA Astrophysics Data System (ADS)

    Brückner, W.; Baunack, St.; Elefant, D.; Reiss, G.

    1996-06-01

    The thin-film system Ni0.37Cr0.63/Cu0.57Ni0.42Mn0.01/Ni0.37Cr0. 63 with a typical thickness of 1 μm is used for low-ohmic precision resistors. The necessary adjustment of the temperature coefficient of resistance (TCR) by annealing has been studied by investigating the irreversible changes of the resistance during various annealing steps of NiCr/CuNi(Mn)/NiCr multilayers in comparison with single layers of CuNi(Mn) and NiCr. Auger depth profiles showed that the interdiffusion of CuNi(Mn) and NiCr results in an impoverishment of Ni in CuNi(Mn), explaining the TCR shift by comparison with data of Cu1-xNix bulk material. The decrease of the resistivity and the reduction of the width of the copper-nickel conductive layer by formation of a Ni0.6Cr0.2Cu0.2 interdiffusion zone phase (in accordance with the Cu-Ni-Cr phase diagram) cause a significant curvature of the resistance-temperature curve. As main result, it is shown that the NiCr base and cover layers and their interdiffusion with CuNi(Mn) play the decisive role in adjusting the TCR. It was checked that oxidation and topography effects have no remarkable influences.

  1. Artist Impression of Hot

    NASA Image and Video Library

    2015-12-14

    This image shows an artist's impression of the 10 hot Jupiter exoplanets studied using the Hubble and Spitzer space telescopes. From top left to lower left, these planets are WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b. The colors of the planets are for illustration purposes only. There is little scientific data on color with the exception of HD 189733b, which became known as the "blue planet." The planets are also depicted with a variety of different cloud properties. The wind patterns shown on these 10 planets, which resemble the visible structures on Jupiter, are based on theoretical models. The illustrations are to scale with each other. HAT-P-12b, the smallest of these planets, is approximately the size of Jupiter, while WASP-17b, the largest one in the sample, is almost twice the size. The hottest planets within the sample are portrayed with a glowing night side. This effect is strongest on WASP-12b, the hottest exoplanet in the sample, but also visible on WASP-19b and WASP-17b. It is also known that several of the planets exhibit strong Rayleigh scattering. This effect causes the blue hue of the daytime sky and the reddening of the sun at sunset on Earth. It is also visible as a blue edge on the planets WASP-6b, HD 189733b, HAT-P-12b and HD 209458b. http://photojournal.jpl.nasa.gov/catalog/PIA20056

  2. Host to Hot Jupiter

    NASA Image and Video Library

    2009-04-16

    This image zooms into a small portion of NASA Kepler full field of view -- an expansive, 100-square-degree patch of sky in our Milky Way galaxy. At the center of the field is a star with a known "hot Jupiter" planet, named "TrES-2," zipping closely around it every 2.5 days. Kepler will observe TrES-2 and other known planets as a test to demonstrate that it is working properly, and to obtain new information about those planets. The area pictured is one-thousandth of Kepler's full field of view, and shows hundreds of stars at the very edge of the constellation Cygnus. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft's dust cover was jettisoned. Kepler was designed to hunt for planets like Earth. The mission will spend the next three-and-a-half years staring at the same stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight. To achieve the level of precision needed to spot planets as small as Earth, Kepler's images are intentionally blurred slightly. This minimizes the number of saturated stars. Saturation, or "blooming," occurs when the brightest stars overload the individual pixels in the detectors, causing the signal to spill out into nearby pixels. http://photojournal.jpl.nasa.gov/catalog/PIA11985

  3. 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.

  4. High strength W/TiNi micro-laminated composite with transformation-mediated ductility

    SciTech Connect

    Shao, Yang; Yu, Kaiyuan; Jiang, Daqiang; Yu, Cun; Ren, Yang; Jiang, Xiaohua; Guo, Fangmin; Cui, Lishan

    2016-06-06

    A laminated W/TiNi composite is fabricated by hot pressing under vacuum and subsequent forging. The W and TiNi constituents are about 250 μm and 80 μm respectively in thicknesses and their interfaces are chemically sharp with negligible intermixing. The material exhibits two yielding plateaus and excellent strength-ductility combination during compression tests. In situ X-ray technique is employed to demonstrate that the unusual yielding phenomenon is related to the reversible thermoelastic phase transformation of TiNi layers. Furthermore, such mechanisms also contribute to the damage tolerance of the materials by inhibiting crack propagation in W.

  5. High strength W/TiNi micro-laminated composite with transformation-mediated ductility

    DOE PAGES

    Shao, Yang; Yu, Kaiyuan; Jiang, Daqiang; ...

    2016-06-06

    A laminated W/TiNi composite is fabricated by hot pressing under vacuum and subsequent forging. The W and TiNi constituents are about 250 μm and 80 μm respectively in thicknesses and their interfaces are chemically sharp with negligible intermixing. The material exhibits two yielding plateaus and excellent strength-ductility combination during compression tests. In situ X-ray technique is employed to demonstrate that the unusual yielding phenomenon is related to the reversible thermoelastic phase transformation of TiNi layers. Furthermore, such mechanisms also contribute to the damage tolerance of the materials by inhibiting crack propagation in W.

  6. Do scientists trace hot topics?

    NASA Astrophysics Data System (ADS)

    Wei, Tian; Li, Menghui; Wu, Chensheng; Yan, Xiao-Yong; Fan, Ying; di, Zengru; Wu, Jinshan

    2013-07-01

    Do scientists follow hot topics in their scientific investigations? In this paper, by performing analysis to papers published in the American Physical Society (APS) Physical Review journals, it is found that papers are more likely to be attracted by hot fields, where the hotness of a field is measured by the number of papers belonging to the field. This indicates that scientists generally do follow hot topics. However, there are qualitative differences among scientists from various countries, among research works regarding different number of authors, different number of affiliations and different number of references. These observations could be valuable for policy makers when deciding research funding and also for individual researchers when searching for scientific projects.

  7. Hot-Lava World Illustration

    NASA Image and Video Library

    2016-03-30

    This illustration shows one possible scenario for the hot, rocky exoplanet called 55 Cancri e, which is nearly two times as wide as Earth. New data from NASA Spitzer Space Telescope show that the planet has extreme temperature swings.

  8. Morpheus Lander Hot Fire Test

    NASA Image and Video Library

    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 ...

  9. Do scientists trace hot topics?

    PubMed Central

    Wei, Tian; Li, Menghui; Wu, Chensheng; Yan, Xiao-Yong; Fan, Ying; Di, Zengru; Wu, Jinshan

    2013-01-01

    Do scientists follow hot topics in their scientific investigations? In this paper, by performing analysis to papers published in the American Physical Society (APS) Physical Review journals, it is found that papers are more likely to be attracted by hot fields, where the hotness of a field is measured by the number of papers belonging to the field. This indicates that scientists generally do follow hot topics. However, there are qualitative differences among scientists from various countries, among research works regarding different number of authors, different number of affiliations and different number of references. These observations could be valuable for policy makers when deciding research funding and also for individual researchers when searching for scientific projects. PMID:23856680

  10. Small Friends of Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Nunez, Luis Ernesto; Johnson, John A.

    2017-01-01

    Hot Jupiters are Jupiter-sized gas giant exoplanets that closely orbit their host star in periods of about 10 days or less. Early models hypothesized that these exoplanets formed away from the star, then over time drifted to their characteristically closer locations. However, new theories predict that Hot Jupiters form at their close proximity during the process of core accretion (Batygin et al. 2015). In fact, a super-Earth and a Neptune-sized exoplanet have already been detected in the Hot Jupiter-hosting star WASP-47 (Becker et al. 2015). We will present our analysis of radial velocity time series plots to determine whether low-mass, short-period planets have been previously overlooked in systems of stars which host Hot Jupiters.The SAO REU program is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851.

  11. A Novel Technology to Develop a Nickel-Enriched Layer on Slab Surface by Utilizing NiO-Containing Synthetic Powder

    NASA Astrophysics Data System (ADS)

    Chung, Tae-In; Cho, Jung-Wook; Kang, Youn-Bae

    2016-02-01

    Cu, as one of the typical tramp elements, is known to cause hot shortness during reheating of slabs followed by hot rolling of sheet products. In order to prevent such harmful aspects, a new idea is proposed by using synthetic powders containing NiO in the mold flux during continuous casting of the slab. During the casting, NiO is reduced and absorbed on initial solidified steel shell, and a Ni-rich layer is developed near the surface region of the slab. According to the proposed idea, it is expected that both the Cu solubility and the melting temperature of Cu-segregated region would increase considerably by virtue of Ni-rich layer, which is believed to play an important role to prevent the Cu hot shortness. A series of laboratory-scale experiments were carried out in order to confirm the reduction and the absorption of Ni into the steel matrix. It was observed by SEM-EDS and FE-EPMA that a Ni-enriched layer, as thick as a few hundred μm, formed near the surface of the slab. Also, a number of laboratory-scale heat treatment tests under oxidizing atmosphere showed that the samples with the Ni-enriched layer had a decreased Cu enrichment at the interface between scale and steel, compared to a case without Ni-rich layer. A pilot-plant-scale steel slab (medium carbon steel containing 0.3 wt pct Cu) was obtained in a continuous casting process with the NiO-containing mold flux, and a Ni-enriched layer was also observed. It was concluded that the use of NiO in the mold flux is a promising new approach for suppressing the hot shortness of Cu-containing steel, without an expensive addition of Ni to the whole steel matrix.

  12. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    NASA Astrophysics Data System (ADS)

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-09-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  13. Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst

    PubMed Central

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-01-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability. PMID:24790945

  14. Charge transfer effects in electrocatalytic Ni-C revealed by x-ray photoelectron spectroscopy

    SciTech Connect

    Haslam, G. E.; Chin, X.-Y.; Burstein, G. T.; Sato, K.; Mizokawa, T.

    2012-06-04

    Binary Ni-C thin-film alloys, which have been shown to be passive against corrosion in hot sulphuric acid solution whilst also being electrocatalytically active, were investigated by XPS to determine the oxidation state of the metal and carbon components. The Ni component produces a Ni 2p spectrum similar to that of metallic nickel (i.e., no oxidation occurs) but with a 0.3 eV shift to higher binding energy (BE) due to electron donation to the carbon matrix. The C 1s peak shows a shift to lower BE by accepting electrons from the Ni nanocrystals. A cluster-model analysis of the observed Ni 2p spectrum is consistent with the electron transfer from the nickel to the carbon.

  15. Preliminary investigation of a NiAl composite prepared by cryomilling

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Arzt, Eduard; Luton, Michael J.

    1990-01-01

    An attempt has been made to improve the high temperature mechanical strength of the B2 cubic crystal structure intermetallic NiAl by dispersion strengthening. Prealloyed Ni-51 at. pct Al was cryomilled with a Y2O3 addition to form an yttria dispersoid within the intermetallic matrix. Following milling, the powder was hot extruded to full density and machined into test coupons. Compression testing between 1200 and 1400 K indicated that the cryogenic process yielded the strongest NiAl based material tested to date. Creep resistance was six times better than NiAl and twice that of a NiAl particulate composite containing 10 vol pct TiB2. Surprisingly, transmission electron microscopy revealed that the second phase was inhomogeneously distributed. Furthermore, X-ray analysis indicated that the second phase was not Y2O3 but rather AlN.

  16. The 1200 K compressive properties of N-containing NiAl

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Noebe, R. D.; Wheeler, D. R.

    1995-01-01

    As part of a series of experiments to understand the role of N on the strength of NiAl, a heat of NiAl was enriched with N by melting and atomization to powder in a nitrogen atmosphere. Following consolidation of the powder by hot extrusion, 1200 K compressive properties were measured in air. Within the range of strain rates examined, 10(exp -3) to 10(exp -9) s(exp -1), the strength of the N-enriched NiAl was greater than that of a simple 15 micron grain size polycrystalline, binary NiAl alloy. For the most part the overall improvement in strength is ascribed to the fine grain size of the N-doped NiAl rather than the alloy chemistry; however, the alloy displayed a complex behavior exhibiting both weakening effects as well as strengthening ones.

  17. Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst.

    PubMed

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-01-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  18. Effects of surface chemistry on hot corrosion life

    NASA Technical Reports Server (NTRS)

    Fryxell, R. E.; Leese, G. E.

    1986-01-01

    Burner rig tests were conducted under the following conditions: 900 C, hourly thermal cycling, 0.5 ppm sodium as NaCl in the gas stream, and Mach 0.3 velocity. The alloys tested were Udimet 700 (U700) and Rene 80, uncoated and with RT21, Codep, or NiCoCrAlY coatings. The tests, up to 1000 hours, included specimens in the as-processed condition and after aging at 1100 C in oxidizing or inert environments for up to 600 hours. Coil-inductance changes were measured for periodic nondestructive inspection of speciments and found useful in the following course of corrosion. Typical sulfidation observed in all cases was similar to that observed in service-run turbine components. Aging at 1100 C caused severe decrease in the hot corrosion life of RT21 and Codep coatings and a significant but lesser decrease in the life of NiCoCrAlY coatings. The extent of these decreases was much greater for all three coatings on U700 than on Rene substrates. A coating hot corrosion life-predicitin model was proposed. The model requires time/temperature information for a turbine component at takeoff conditions as well as environmental contaminant information.

  19. Processing, physical metallurgy and creep of NiAl + Ta and NiAl + Nb alloys. Ph.D. Thesis. Final Contractor Report

    NASA Technical Reports Server (NTRS)

    Pathare, Viren M.

    1988-01-01

    Powder processed NiAl + Ta alloys containing 1, 2, and 4.5 at percent tantalum and NiAl + Nb alloys containing 1 and 2 at percent niobium were developed for improved creep properties. In addition, a cast alloy with 5 at percent tantalum was also studied. Hot extrusion parameters for processing alloys with 1 and 2 at percent of tantalum or niobium were designed. The NiAl + 4.5 at percent Ta alloy could be vacuum hot pressed successfully, even though it could not be extruded. All the phases in the multiphase alloys were identified and the phase transformations studied. The Ni2AlTa in NiAl + 4.5 at percent Ta alloy transforms into a liquid phase above 1700 K. Solutionizing and annealing below this temperature gives rise to a uniform distribution of fine second phase precipitates. Compressive creep properties were evaluated at 1300 K using constant load and constant velocity tests. In the higher strain rate region single phase NiAl + 1 at percent Ta and NiAl + 1 at percent Nb alloys exhibit a stress exponent of 5 characteristic of climb controlled dislocation creep. In slower strain rate regime diffusional creep becomes important. The two phase alloys containing 2 to 5 at percent Ta and 2 at percent Nb show considerable improvement over binary NiAl and single phase alloys. Loose dislocation networks and tangles stabilized by the precipitates were found in the as crept microstructure. The cast alloy which has larger grains and a distribution of fine precipitates shows the maximum improvement over binary NiAl.

  20. Neptune's Wandering Hot Pole

    NASA Astrophysics Data System (ADS)

    Orton, Glenn; Fletcher, Leigh; Yanamandra-Fisher, Padma; Geballe, Tom; Hammel, Heidi; Fujiyoshi, Takuya; Encrenaz, Therese; Hofstadter, Mark; Mousis, Olivier; Fuse, Tetsuharu

    2010-05-01

    Images of stratospheric emission from Neptune obtained in 2006 at ESO's Very Large Telescope (Orton et al., 2007, A&A 473, L5) revealed a near-polar hot spot near 70 deg. S latitude that was detectable in different filters sampling both methane (~7-micron) and ethane (~12-micron) emission from Neptune's stratosphere. Such a feature was not present in 2003 Keck and 2005 Gemini North observations: these showed only a general warming trend towards Neptune's pole that was longitudinally homogeneous. Because of the paucity of longitudinal sampling in the 2003, 2005 and 2006 images, it was not clear whether the failure to see this phenomenon in 2003 and 2005 was simply the result of insufficient longitudinal sampling or whether the phenomenon was truly variable in time. To unravel these two possibilities, we proposed for time on large telescopes that were capable of resolving Neptune at these wavelengths. We were granted time at Gemini South in 2007 using T-Recs, Subaru time in 2008 using the COMICS instrument and VLT time in 2008 and 2009 using VISIR. Two serendipitous T-Recs images of Neptune were also obtained in 2007 using a broad-band N (8-14 micron) filter, whose radiance is dominated by 12-micron ethane emission, and whose primary purpose was navigation of N-band spectroscopy. The feature was re-observed (i) in 2007 in the T-Recs N-band filter and (ii) in 2008 with COMICS in a 12.5-micron image. Unfortunately, none of the telescope time granted was sufficient to sample all longitudes over the 12-hour period of this latitude, and so no definitive separation of the two possibilities was obtained. However, considering the ensemble of images as a random sample of longitudes, it is likely that the phenomenon is ephemeral in time, as it was observed only twice among 9 independent observing epochs. We will continue to request observations to sample all longitudes systematically, but our current sample argues that the phenomenon is truly ephemera, because we most likely

  1. 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.

  2. Hot embossing of PTFE: Towards superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Jucius, D.; Grigaliūnas, V.; Mikolajūnas, M.; Guobienė, A.; Kopustinskas, V.; Gudonytė, A.; Narmontas, P.

    2011-01-01

    Three types of reusable stamps with features in the form of 2D arrays of pits having lateral dimensions in the range of 2-80 μm and heights of 1.5-15 μm were successfully employed for the hot embossing of PTFE at temperatures up to 50 °C above the glass transition temperature of PTFE amorphous phase. Due to the softening of PTFE at the temperatures used in this study, we were able to decrease imprint pressure significantly when comparing with the imprint conditions reported by other authors. Impact of the imprint temperature, pressure and time on the fidelity of pattern transfer as well as on water repellency was tested. The best results of embossing were achieved by applying pressure of 10 kg/cm 2 for 2 min at 170 °C. In this case, flattening of a natural PTFE roughness and pretty accurate deep replicas of the stamp patterns were observable on the whole imprinted area. Improvement in water repellency was largest for the samples imprinted by Ni stamp patterned with a 2D array of 2 μm square pits spaced by the same dimension and having a depth of 1.5 μm. Cassie-Baxter wetting regime was observed for the deepest imprints with water contact angles up to the superhydrophobic limit.

  3. Extreme April 2016 temperatures in Mainland Southeast Asia caused by El Niño and exacerbated by global warming

    NASA Astrophysics Data System (ADS)

    Thirumalai, K.; Di Nezio, P. N.; Okumura, Y.; Deser, C.

    2016-12-01

    In April 2016, Mainland Southeast Asia (MSA) experienced monthly mean surface air temperatures (SATs) that surpassed national records, caused widespread discomfort, and greatly exacerbated energy consumption. First, we reveal a robust relationship between the El Niño Southern Oscillation (ENSO) and April SATs in the region, demonstrating that virtually all extreme, hot Aprils occur during El Niño years. Next, we show that MSA has experienced continuous warming since the early 20th century. To quantify the relative contributions of this long-term warming trend and the 2015 El Niño to the extreme April 2016 SATs, we use observations and a large ensemble of global warming simulations, performed with a model that realistically simulates this El-Niño-MSA link. We find robust evidence that the "post-Niño" hot Aprils are being exacerbated by global warming, with this effect being pronounced for the 2016 event, where we estimate 24% was caused by warming and 49% by El Niño. Despite an increased likelihood of hot Aprils during El Niño years in the future, our findings suggest that these extremes can potentially be anticipated a few months in advance.

  4. Long-Length Semiproducts from Ni - Ti Alloys with Advanced Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Andreev, V. A.; Yusupov, V. S.; Perkas, M. M.; Prosvirnin, V. V.; Bondareva, S. A.

    2015-05-01

    The effect of cold deformation and heat treatment on the mechanical properties of hot-rolled long-length semiproducts from shape-memory Ni - Ti alloys is studied. It is shown that cold deformation to ɛtot = 30% with intermediate annealing operations promotes reversible changes in the shape. The effect may be associated with relaxation of oriented microstresses created during plastic deformation.

  5. Hot Alps (Invited)

    NASA Astrophysics Data System (ADS)

    Speranza, F.; Minelli, L.; Pignatelli, A.; Gilardi, M.

    2013-12-01

    Although it is frequently assumed that crust of Alpine orogens is hot due to the occurrence of thick and young (hence radiogenic) crust, evidence on the thermal ranking of orogens is contradictory. Heat flow measurements from shallow wells (depth ≤ 1 km) in the Alps yield a relatively cold thermal regime of 50-80 mW/m2, but data are likely biased by meteoric cold-water circulation. Here we report on the spectral analysis of the aeromagnetic residuals of northern Italy to derive the Curie point depth (CPD), assumed to represent the 600°C isotherm depth. Airborne magnetics were acquired on whole Italy during the 1970s by the national oil company AGIP (now Eni). Data were gathered by several surveys carried out at 1000-13,300 feet (300-4000 m) altitude, with flight line spacing of 2-10 km. Surveys of the Alps and Po Plain (northern Italy) were obtained both with a line spacing of 5 km (and 5 km tie lines), at an altitude of 4000-5000 and 13,300 feet, respectively. To evaluate CPDs we used the centroid method (routinely adopted in recent CPD studies on East Asia and central-southern Europe) on 72 square windows of 100-110 km edge, with a 50% degree of superposition. CPDs vary between 16 and 38 km (22 km on average) in the Po Plain, located south of the Alps and representing the Adriatic-African foreland area. Conversely, the Alps yield very shallow CPDs, ranging between 6 and 15 km (10 km on average). CPDs fall systematically above local Moho depths, implying that magnetic source bottoms documented in this study do not represent a lithological boundary over non-magnetic peridotitic mantle, but can be safely associated with CPDs and the 600°C isotherm. CPDs from the Po Plain are in rough agreement with reported heat flow values of 25-60 mW/m2, and imply and average thermal conductivity (k) of the Po Plain crust of 1.5 W/m°K, at the lower bound of k values measured and inferred for the crust. Conversely, the average 10 km CPD documented in the Alps translates into

  6. Coatings for Oxidation and Hot Corrosion Protection of Disk Alloys

    NASA Technical Reports Server (NTRS)

    Nesbitt, Jim; Gabb, Tim; Draper, Sue; Miller, Bob; Locci, Ivan; Sudbrack, Chantal

    2017-01-01

    Increasing temperatures in aero gas turbines is resulting in oxidation and hot corrosion attack of turbine disks. Since disks are sensitive to low cycle fatigue (LCF), any environmental attack, and especially hot corrosion pitting, can potentially seriously degrade the life of the disk. Application of metallic coatings are one means of protecting disk alloys from this environmental attack. However, simply the presence of a metallic coating, even without environmental exposure, can degrade the LCF life of a disk alloy. Therefore, coatings must be designed which are not only resistant to oxidation and corrosion attack, but must not significantly degrade the LCF life of the alloy. Three different Ni-Cr coating compositions (29, 35.5, 45wt. Cr) were applied at two thicknesses by Plasma Enhanced Magnetron Sputtering (PEMS) to two similar Ni-based disk alloys. One coating also received a thin ZrO2 overcoat. The coated samples were also given a short oxidation exposure in a low PO2 environment to encourage chromia scale formation. Without further environmental exposure, the LCF life of the coated samples, evaluated at 760C, was less than that of uncoated samples. Hence, application of the coating alone degraded the LCF life of the disk alloy. Since shot peening is commonly employed to improve LCF life, the effect of shot peening the coated and uncoated surface was also evaluated. For all cases, shot peening improved the LCF life of the coated samples. Coated and uncoated samples were shot peened and given environmental exposures consisting of 500 hrs of oxidation followed by 50 hrs of hot corrosion, both at 760C). The high-Cr coating showed the best LCF life after the environmental exposures. Results of the LCF testing and post-test characterization of the various coatings will be presented and future research directions discussed.

  7. Ag/Ni Metallization Bilayer: A Functional Layer for Highly Efficient Polycrystalline SnSe Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Park, Sang Hyun; Jin, Younghwan; Ahn, Kyunghan; Chung, In; Yoo, Chung-Yul

    2017-02-01

    The structural and electrical characteristics of Ag/Ni bilayer metallization on polycrystalline thermoelectric SnSe were investigated. Two difficulties with thermoelectric SnSe metallization were identified for Ag and Ni single layers: Sn diffusion into the Ag metallization layer and unexpected cracks in the Ni metallization layer. The proposed Ag/Ni bilayer was prepared by hot-pressing, demonstrating successful metallization on the SnSe surface without interfacial cracks or elemental penetration into the metallization layer. Structural analysis revealed that the Ni layer reacts with SnSe, forming several crystalline phases during metallization that are beneficial for reducing contact resistance. Detailed investigation of the Ni/SnSe interface layer confirms columnar Ni-Sn intermetallic phases [(Ni3Sn and Ni3Sn2) and Ni5.63SnSe2] that suppress Sn diffusion into the Ag layer. Electrical specific-contact resistivity (5.32 × 10-4 Ω cm2) of the Ag/Ni bilayer requires further modification for development of high-efficiency polycrystalline SnSe thermoelectric modules.

  8. Thermal expansion behavior of NiSi/NiSi2

    NASA Technical Reports Server (NTRS)

    Wilson, D. F.; Cavin, O. B.

    1992-01-01

    The thermal expansion of NiSi/NiSi2 for a range of temperatures from 293 to 1223 K was determined using high-temperature X-ray diffraction. While a linear relation with temperature was found for the lattice parameter of NiSi2, third-order relationships were found for the three lattice parameters of NiSi, with one of the parameters showing a decrease with increasing temperature. The volumetric expansion of both materials exhibited linear relationships.

  9. 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.

  10. Characterization and fixed-bed testing of a nickel-based hot gas desulfurization sorbent

    SciTech Connect

    Gasper-Galvin, L.D.; Swisher, J.H.; Hammerbeck, K.

    1994-10-01

    The objective of this project was to (1) extend a preliminary investigation completed earlier on dispersed nickel sorbents by developing new processing methods, characterizing sorbent materials more extensively, and evaluating the materials in fixed bed reactor tests, and (2) to determine the feasibility of using dispersed nickel sorbents with reductive regeneration for hot gas desulfurization. One of the properties of nickel that is somewhat unique is that it forms a liquid sulfide at sufficiently high temperatures with high sulfur potentials or H{sub 2}S levels. A eutectic exists in the Ni-S phase diagram at 637 C and a composition of 33.4 wt% or 21.5 wt% S. Under controlled conditions, the formation of a liquid phase can be used to advantage in hot gas desulfurization. Sorbent preparation, the experimental unit, and experimental procedure are described. Results from the sorbent, 24Ni-7Cu-Al{sub 2}O{sub 3}, are given.

  11. Ni-Co laterite deposits

    USGS Publications Warehouse

    Marsh, Erin E.; Anderson, Eric D.

    2011-01-01

    Nickel-cobalt (Ni-Co) laterite deposits are an important source of nickel (Ni). Currently, there is a decline in magmatic Ni-bearing sulfide lode deposit resources. New efforts to develop an alternative source of Ni, particularly with improved metallurgy processes, make the Ni-Co laterites an important exploration target in anticipation of the future demand for Ni. This deposit model provides a general description of the geology and mineralogy of Ni-Co laterite deposits, and contains discussion of the influences of climate, geomorphology (relief), drainage, tectonism, structure, and protolith on the development of favorable weathering profiles. This model of Ni-Co laterite deposits represents part of the U.S. Geological Survey Mineral Resources Program's effort to update the existing models to be used for an upcoming national mineral resource assessment.

  12. 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.

  13. 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.

  14. Prometheus Hot Leg Piping Concept

    NASA Astrophysics Data System (ADS)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    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.

  15. Science with hot astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Kaastra, J. S.; Gu, L.; Mao, J.; Mehdipour, M.; Mernier, F.; de Plaa, J.; Raassen, A. J. J.; Urdampilleta, I.

    2017-08-01

    We present some recent highlights and prospects for the study of hot astrophysical plasmas. Hot plasmas can be studied primarily through their X-ray emission and absorption. Most astrophysical objects, from solar system objects to the largest scale structures of the Universe, contain hot gas. In general we can distinguish collisionally ionised gas and photoionised gas. We introduce several examples of both classes and show where the frontiers of this research in astrophysics can be found. We put this also in the context of the current and future generation of X-ray spectroscopy satellites. The data coming from these missions challenge the models that we have for the calculation of the X-ray spectra.

  16. FG Sagittae - No hot companion?

    NASA Technical Reports Server (NTRS)

    Feibelman, Walter A.; Bruhweiler, Frederick C.

    1990-01-01

    The nucleus of the planetary nebula He 1-5 (= PK 60 -7 deg 1), the variable star FG Sge, was observed with the SWP camera of the International Ultraviolet Explorer satellite to detect a hot companion of the star, if such a companion exists. The observation found no evidence for the existance of a hot companion in the 1200-2000 A range of the SWP camera and supported the contention that FG Sge underwent a helium shell flash during the past century, and that the surrounding nebula, He 1-5, is a nebula of fossil ionization. Despite the currently accepted fossil ionization model, constraints posed by the satellite detection limit, the observed H-beta flux, and the adopted radii for white dwarfs still allow the possibility of a putative hot companion photoionizing this nebula.

  17. 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.

  18. Hot temperatures line lists for metal hydrides

    NASA Astrophysics Data System (ADS)

    Gorman, M.; Lodi, L.; Leyland, P. pC; Hill, C.; Yurchenko, S. N.; Tennyson, J.

    2013-09-01

    The ExoMol project is an ERC funded project set up with the purpose of calculating high quality theoretical molecular line list data to facilitate the emerging field of exoplanet and cool star atmospheric haracterisation [1]. Metal hydrides are important building blocks of interstellar physical chemistry. For molecular identification and characterisation in astrophysical sources, one requires accurate and complete spectroscopic data including transitional frequencies and intensities in the form of a line list. The ab initio methods offer the best opportunity for detailed theoretical studies of free diatomic metal hydrides and other simple hydride molecules. In this contribution we present progress on theoretical line lists for AlH, CrH, MgH, NiH, NaH and TiH obtained from first principles, applicable for a large range of temperatures up to 3500 K. Among the hydrides, AlH is of special interest because of a relatively high cosmic abundance of aluminium. The presence of AlH has been detected in the spectra of M-type and S-type stars as well as in sunspots (See [2] and references therein). CrH is a molecule of astrophysical interest; under the classification scheme developed by Kirkpatrick et al [3], CrH is of importance in distinguishing L type brown dwarfs. It has been proposed that theoretical line-lists of CrH and CrD could be used to facilitate a 'Deuterium test' for use in distinguishing planets, brown dwarfs and stars [5] and also it has been speculated that CrH exists in sunspots [4] but a higherquality hot-temperature line-list is needed to confirm this finding. The presence of MgH in stellar spectra is well documented through observation of the A2 ! X 2+ and B0 2+ ! X 2+ transitions. Different spectral features of MgH have been used as an indicator for the magnesium isotope abundances in the atmospheres of different stars from giants to dwarfs including the Sun, to measure the temperature of stars, surface gravity, stars' metal abundance, gravitational, as

  19. 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.

  20. 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.

  1. 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.

  2. The oxidation of Ni-rich Ni-Al intermetallics

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph; Smialek, James L.; Barrett, Charles A.

    1988-01-01

    The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al2O3 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.

  3. Preliminary studies on NiAl/Nb2Be17 reaction and effectiveness of BeO as an interfacial reaction barrier

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1991-01-01

    The interfacial reaction between NiAl and Nb2Be17 (used as a reinforcement for the alloy) was studied by measuring diffusion bonding of NiAl and Nb2Be17 plates in a hot press under a vacuum of 10 exp -5 atm. It was found that, after 2 hrs of hot pressing at 1373 K, the reaction between NiAl and Nb2Be17 was extensive. A 40 to 50-micron-thick reaction zone consisted of three distinct layers at the NiAl/Nb2Be17 interface: layer A next to Nb2Be17, layer B in the middle, and layer C next to NiAl. Results of analysis of the reaction layers using energy dispersive spectroscopy (EDS) were inconclusive because of the inabiliaty of EDS to detect Be.

  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. 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…

  6. 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.

  7. 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.

  8. Clouds on Hot Jupiters Illustration

    NASA Image and Video Library

    2016-10-18

    Hot Jupiters are exoplanets that orbit their stars so tightly that their temperatures are extremely high, reaching over 2,400 degrees Fahrenheit (1600 Kelvin). They are also tidally locked, so one side of the planet always faces the sun and the other is in permanent darkness. Research suggests that the "dayside" is largely free of clouds, while the "nightside" is heavily clouded. This illustration represents how hot Jupiters of different temperatures and different cloud compositions might appear to a person flying over the dayside of these planets on a spaceship, based on computer modeling. Cooler planets are entirely cloudy, whereas hotter planets have morning clouds only. Clouds of different composition have different colors, whereas the clear sky is bluer than on Earth. For the hottest planets, the atmosphere is hot enough on the evening side to glow like a charcoal. Figure 1 shows an approximation of what various hot Jupiters might look like based on a combination of computer modeling and data from NASA's Kepler Space Telescope. From left to right it shows: sodium sulfide clouds (1000 to 1200 Kelvin), manganese sulfide clouds (1200 to 1600 Kelvin), magnesium silicate clouds (1600 to 1800 Kelvin), magnesium silicate and aluminum oxide clouds (1800 Kelvin) and clouds composed of magnesium silicate, aluminum oxide, iron and calcium titanate (1900 to 2200 Kelvin). http://photojournal.jpl.nasa.gov/catalog/PIA21074

  9. Solar Hot Water Hourly Simulation

    SciTech Connect

    Walker, Howard Andrew

    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).

  10. Sources of antibiotics: Hot springs.

    PubMed

    Mahajan, Girish B; Balachandran, Lakshmi

    2016-11-24

    The discovery of antibiotics heralded an era of improved health care. However, the over-prescription and misuse of antibiotics resulted in the development of resistant strains of various pathogens. Since then, there has been an incessant search for discovering novel compounds from bacteria at various locations with extreme conditions. The soil is one of the most explored locations for bioprospecting. In recent times, hypersaline environments and symbiotic associations have been investigated for novel antimicrobial compounds. Among the extreme environments, hot springs are comparatively less explored. Many researchers have reported the presence of microbial life and secretion of antimicrobial compounds by microorganisms in hot springs. A pioneering research in the corresponding author's laboratory resulted in the identification of the antibiotic Fusaricidin B isolated from a hot spring derived eubacteria, Paenibacillus polymyxa, which has been assigned a new application for its anti-tubercular properties. The corresponding author has also reported anti-MRSA and anti-VRE activity of 73 bacterial isolates from hot springs in India.

  11. Microsensor Hot-Film Anemometer

    NASA Technical Reports Server (NTRS)

    Mcginley, Catherine B.; Stephens, Ralph; Hopson, Purnell; Bartlett, James E.; Sheplak, Mark; Spina, Eric F.

    1995-01-01

    Improved hot-film anemometer developed for making high-bandwidth turbulence measurements in moderate-enthalpy supersonic and hypersonic flows (e.g., NASP inlets and control surfaces, HSCT jet exhaust). Features include low thermal inertia, ruggedness, and reduced perturbation of flow.

  12. 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.

  13. 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)

  14. Types of Hot Jupiter Atmospheres

    NASA Astrophysics Data System (ADS)

    Bisikalo, Dmitry V.; Kaygorodov, Pavel V.; Ionov, Dmitry E.; Shematovich, Valery I.

    Hot Jupiters, i.e. exoplanet gas giants, having masses comparable to the mass of Jupiter and semimajor axes shorter than 0.1 AU, are a unique class of objects. Since they are so close to the host stars, their atmospheres form and evolve under the action of very active gas dynamical processes caused by the gravitational field and irradiation of the host star. As a matter of fact, the atmospheres of several of these planets fill their Roche lobes , which results in a powerful outflow of material from the planet towards the host star. The energy budget of this process is so important that it almost solely governs the evolution of hot Jupiters gaseous envelopes. Based on the years of experience in the simulations of gas dynamics in mass-exchanging close binary stars, we have investigated specific features of hot Jupiters atmospheres. The analytical estimates and results of 3D numerical simulations, discussed in this Chapter, show that the gaseous envelopes around hot Jupiters may be significantly non-spherical and, at the same time, stationary and long-lived. These results are of fundamental importance for the interpretation of observational data.

  15. Bulk Migration of Ni/NiO in Ni-YSZ during Reducing Conditions

    SciTech Connect

    Saraf, Laxmikant V.; Baer, Donald R.; Lea, Alan S.; Zhu, Zihua; Strohm, James J.; Sitzman, S. D.; King, David L.

    2010-02-09

    Understanding the migration of Ni/NiO in Ni-YSZ can potentially help to design a better solid oxide fuel cell (SOFC) anode. We have observed that extensive hydrogen reduction and methane steam reforming of Ni-YSZ caused bulk migration of Ni/NiO to at least ~ 5 µm deeper from the Ni-YSZ surface. No significant bulk migration effects were detected after simple thermal treatments in non-reducing/non-reforming environment. Surface analysis of a single zirconia grain in the first 10-20 nm region from annealed, hydrogen reduced and methane steam reformed Ni-YSZ shows Ni-enriched surface supporting earlier claims of Ni exsolution. 3D-EBSD analysis of thermally treated sample before exposing it to reducing and reforming environment indicated mixed NiO/YSZ phase with some porosity and random grain orientation. The surface analysis and mapping were carried out using ToF-SIMS and AES whereas EDS maps on FIB sliced areas on Ni-YSZ were utilized for the bulk analysis. The results provide additional information related to complex reactions occurring in SOFC during internal reforming conditions.

  16. Detection of Hot Halo Gets Theory Out of Hot Water

    NASA Astrophysics Data System (ADS)

    2006-02-01

    Scientists using NASA's Chandra X-ray Observatory have detected an extensive halo of hot gas around a quiescent spiral galaxy. This discovery is evidence that galaxies like our Milky Way are still accumulating matter from the gradual inflow of intergalactic gas. "What we are likely witnessing here is the ongoing galaxy formation process," said Kristian Pedersen of the University of Copenhagen, Denmark, and lead author of a report on the discovery. Chandra observations show that the hot halo extends more than 60,000 light years on either side of the disk of the galaxy known as NGC 5746. The detection of such a large halo alleviates a long-standing problem for the theory of galaxy formation. Spiral galaxies are thought to form from enormous clouds of intergalactic gas that collapse to form giant, spinning disks of stars and gas. Chandra X-ray Image of NGC 5746 Chandra X-ray Image of NGC 5746 One prediction of this theory is that large spiral galaxies should be immersed in halos of hot gas left over from the galaxy formation process. Hot gas has been detected around spiral galaxies in which vigorous star formation is ejecting matter from the galaxy, but until now hot halos due to infall of intergalactic matter have not been detected. "Our observations solve the mystery of the missing hot halos around spiral galaxies," said Pedersen. "The halos exist, but are so faint that an extremely sensitive telescope such as Chandra is needed to detect them." DSS Optical Image of NGC 5746 DSS Optical Image of NGC 5746 NGC 5746 is a massive spiral galaxy about a 100 million light years from Earth. Its disk of stars and gas is viewed almost edge-on. The galaxy shows no signs of unusual star formation, or energetic activity from its nuclear region, making it unlikely that the hot halo is produced by gas flowing out of the galaxy. "We targeted NGC 5746 because we thought its distance and orientation would give us the best chance to detect a hot halo caused by the infall of

  17. Carbon nanotube substrates and catalyzed hot stamp for polishing and patterning the substrates

    DOEpatents

    Wang, Yuhuang [Evanston, IL; Hauge, Robert H [Houston, TX; Schmidt, Howard K [Houston, TX; Kim, Myung Jong [Houston, TX; Kittrell, W Carter [Houston, TX

    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.

  18. Enriching the hot circumgalactic medium

    NASA Astrophysics Data System (ADS)

    Crain, Robert A.; McCarthy, Ian G.; Schaye, Joop; Theuns, Tom; Frenk, Carlos S.

    2013-07-01

    Simple models of galaxy formation in a cold dark matter universe predict that massive galaxies are surrounded by a hot, quasi-hydrostatic circumgalactic corona of slowly cooling gas, predominantly accreted from the intergalactic medium (IGM). This prediction is borne out by the recent cosmological hydrodynamical simulations of Crain et al., which reproduce observed scaling relations between the X-ray and optical properties of nearby disc galaxies. Such coronae are metal poor, but observations of the X-ray emitting circumgalactic medium (CGM) of local galaxies typically indicate enrichment to near-solar iron abundance, potentially signalling a shortcoming in current models of galaxy formation. We show here that, while the hot CGM of galaxies formed in the simulations is typically metal poor in a mass-weighted sense, its X-ray luminosity-weighted metallicity is often close to solar. This bias arises because the soft X-ray emissivity of a typical ˜0.1 keV corona is dominated by collisionally excited metal ions that are synthesized in stars and recycled into the hot CGM. We find that these metals are ejected primarily by stars that form in situ to the main progenitor of the galaxy, rather than in satellites or external galaxies. The enrichment of the hot CGM therefore proceeds in an `inside-out' fashion throughout the assembly of the galaxy: metals are transported from the central galaxy by supernova-driven winds and convection over several Gyr, establishing a strong negative radial metallicity gradient. Whilst metal ions synthesized by stars are necessary to produce the X-ray emissivity that enables the hot CGM of isolated galaxies to be detected with current instrumentation, the electrons that collisionally excite them are equally important. Since our simulations indicate that the electron density of hot coronae is dominated by the metal-poor gas accreted from the IGM, we infer that the hot CGM observed via X-ray emission is the outcome of both hierarchical

  19. Preparing TiNiNb shape memory alloy powders by hydriding-dehydriding process

    NASA Astrophysics Data System (ADS)

    Shao, Yang; Cui, Lishan; Jiang, Xiaohua; Guo, Fangmin; Liu, Yinong; Hao, Shijie

    2016-07-01

    High-quality TiNiNb shape memory alloy (SMA) powders were prepared by hydrogenation of cold-worked TiNiNb SMA wire composed of amorphous and nancrystalline microstructure, by mechanical pulverization and vacuum dehydrogenation. It is revealed that abundant structural defects introduced by cold-work greatly promoted hydrogen diffusion, which significantly decreased hydriding temperature and shortened hydriding time. After hydrogenation, the hydrogenated sample composed of TiNiH and NbH with high brittleness can be easily ground into ultra-fine powers. The TiNiNb powers obtained by following vacuum dehydrogenation exhibit almost the same reversible phase transformation behavior as that of the original TiNiNb SMA before cold-work. Moreover, a TiNiNb part was obtained by hot-pressure sintering the hydrogenated powders, where sintering and dehydrogenation are carried out in one single step. The sintered TiNiNb part shows most the same reversible phase transformation behaviors as that of the original TiNiNb SMA and there is no visible additional brittle phase appearance.

  20. 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.

  1. 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.

  2. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    SciTech Connect

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  3. Oxidation and hot corrosion of coated and bare oxide dispersion strengthened superalloy MA-755E

    NASA Technical Reports Server (NTRS)

    Glasgow, T. K.; Santoro, G. J.

    1981-01-01

    Cyclic hot corrosion and oxidation of an experimental oxide dispersion strengthened (ODS) superalloy MA-755E were conducted in a hot gas stream at Mach 0.3. The response of the ODS alloy, bare or with protective coatings, was similar to that of a conventional cast alloy, IN-792, in hot corrosion at 900 C. However, during oxidation at 1100 and 1150 C the ODS alloy differed from the cast alloy by developing a greater amount of subsurface porosity. Compared with a diffused aluminide coating, an electron beam vapor deposited NiCrAlY coating offered superior oxidation protection and decreased porosity formation. In additional testing, the tendency to form porosity was associated with the large grains of recrystallized powder metallurgy alloys but was independent of the presence of an oxide dispersion.

  4. dc-ac hot-wire procedure for determining thermophysical properties under pressure

    NASA Astrophysics Data System (ADS)

    Nilsson, O.; Sandberg, O.; Bäckström, G.

    1986-09-01

    The paper describes a new hot-wire method for simultaneous determination of thermal conductivity and heat capacity per unit volume of electrically insulating liquids and solids under pressure. The method uses dc heating of the hot wire, whereas the temperature increase is recorded by an ac bridge circuit. The temperature data obtained are analyzed using the exact solution instead of the commonly used long time approximation. The procedure was tested on a number of alcohols and water and the accuracy was found to be 1.5%. New data on glycerol up to 1.5 GPa are presented. The appearance of an automagnetoresistance effect when Ni is employed as hot-wire probe is discussed.

  5. Biogeochemistry of Hot Spring Biofilms: Major and Trace Element Behavior

    NASA Astrophysics Data System (ADS)

    Havig, J. R.; Prapaipong, P.; Zolotova, N.; Moore, G.; Shock, E. L.

    2008-12-01

    Hot spring biofilms are of obvious biological origin, but of surprising composition. Organic carbon makes up a minor percentage of the total mass of chemotrophic and phototrophic biofilms. We have found that the majority of biofilm mass is inorganic material, largely silica, with measurable quantities of dozens of other elements, and that the distribution of major elements mimics that of surrounding rock and soil far more closely than the hot spring fluids. Comparisons of biofilms with the compositions of their geochemical surroundings help identify trace elements that are anomalously enriched or depleted. These anomalies provide insight into the processes of active or passive elemental accumulation by biofilms, which could be used to understand microbial processes of element uptake or to identify evidence for life in hydrothermal deposits in the rock record. Five separate hydrothermal systems in Yellowstone National Park were incorporated into this study: 'Bison Pool' and its outflow (siliceous-sinter depositing, temp. = 93.2 to 56.2 C, pH = 7.4 to 8.3), Flatcone Geyser and its outflow (siliceous-sinter depositing, temp. = 94.3 to 44.3 C, pH = 7.9 to 8.8, Boulder Spring and its outflow (siliceous-sinter depositing, temp. = 92.1 to 64.9 C, pH = 8.2 to 8.7), Octopus Spring and its outflow (siliceous-sinter depositing, temp. = 91.4 to 62.8 C, pH = 7.7 to 8.2), and two unnamed locations in the Obsidian Pool area we have dubbed 'Green Cheese' (temp. = 64.5 to 54.9 C, pH = 5.9 to 6.2) and 'Happy Harfer Pool' (temp. = 59.9 to 48.3 C, pH = 5.5 to 6.3). Analysis of water, biofilm, and contextual samples collected from and around these hot springs offer intriguing patterns of elemental behavior, both similar and dissimilar, among the varying systems. Examples of these patterns include elements that behave the same across all hot spring systems (B, C, Ni, Cu, Ge, Sb, and W), elements with behavior that was consistent throughout most (four of five) of the hot spring systems

  6. PCR hot-start using duplex primers.

    PubMed

    Kong, Deming; Shen, Hanxi; Huang, Yanping; Mi, Huaifeng

    2004-02-01

    A new technique of PCR hot-start using duplex primers has been developed which can decrease the undesirable products arising throughout PCR amplification thereby giving better results than a manual hot-start method.

  7. From Hot Flashes to Cool Insights: Menopause

    MedlinePlus

    ... JavaScript on. Feature: Menopause From Hot Flashes to Cool Insights: Menopause Past Issues / Winter 2017 Table of ... Read More "Menopause" Articles From Hot Flashes to Cool Insights: Menopause / Treatment Tips From the National Institute ...

  8. 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.

  9. Acupuncture for menopausal hot flushes.

    PubMed

    Dodin, Sylvie; Blanchet, Claudine; Marc, Isabelle; Ernst, Edzard; Wu, Taixiang; Vaillancourt, Caroline; Paquette, Joalee; Maunsell, Elizabeth

    2013-07-30

    Hot flushes are the most common menopausal vasomotor symptom. Hormone therapy (HT) has frequently been recommended for relief of hot flushes, but concerns about the health risks of HT have encouraged women to seek alternative treatments. It has been suggested that acupuncture may reduce hot flush frequency and severity. To determine whether acupuncture is effective and safe for reducing hot flushes and improving the quality of life of menopausal women with vasomotor symptoms. We searched the following databases in January 2013: the Cochrane Menstrual Disorders and Subfertility Group Specialised Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, CINAHL, PsycINFO, Chinese Biomedical Literature Database (CBM), Chinese Medical Current Content (CMCC), China National Knowledge Infrastructure (CNKI), VIP database, Dissertation Abstracts International, Current Controlled Trials, Clinicaltrials.gov, National Center for Complementary and Alternative Medicine (NCCAM), BIOSIS, AMED, Acubriefs, and Acubase. Randomized controlled trials comparing any type of acupuncture to no treatment/control or other treatments for reducing menopausal hot flushes and improving the quality of life of symptomatic perimenopausal/postmenopausal women were eligible for inclusion. Sixteen studies, with 1155 women, were eligible for inclusion. Three review authors independently assessed trial eligibility and quality, and extracted data. We pooled data where appropriate and calculated mean differences (MDs) and standardized mean differences (SMDs) with 95% confidence intervals (CI). We evaluated the overall quality of the evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Eight studies compared acupuncture versus sham acupuncture. No significant difference was found between the groups for hot flush frequency (MD -1.13 flushes per day, 95% CI -2.55 to 0.29, 8 RCTs, 414 women, I(2) = 70%, low-quality evidence

  10. 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.

  11. Further Studies Of Hot-Wire Anemometry

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert; Logan, Pamela; Bershader, Daniel

    1990-01-01

    Report discusses factors affecting readings of hot-wire anemometer in turbulent supersonic boundary layer. Represents extension of work described in "Hot-Wire Anemometry Versus Laser-Induced Fluorescence" (ARC-11802). Presents theoretical analysis of responses of hot-wire probe to changes in flow; also compares measurements by hot-wire probe with measurements of same flows by laser-induced fluorescence (LIF).

  12. Aluminizing and boroaluminizing treatments of Mar-M247 and their effect on hot corrosion resistance in Na2SO4-NaCl molten salt

    NASA Astrophysics Data System (ADS)

    Cho, J. H.; Kim, T. W.; Son, K. S.; Yoon, J. H.; Kim, H. S.; Leisk, G. G.; Mitton, D. B.; Latanision, R. M.

    2003-06-01

    The effect of surface modifications of Mar-M247 superalloy on hot corrosion resistance was examined in Na2SO4-NaCl molten salt. The Mar-M247 was aluminized and boroaluminized by pack cementation in Ar and underwent a cyclic hot corrosion test in Na2SO4-NaCl molten salt. The XRD results showed that a Ni2Al3 phase was formed between the aluminized layer and the substrate when the surface modification temperature was below 1273 K. However, a NiAl phase formed when the temperature was above 1273 K. The intensity of the XRD peak in the NiAl phase increased after post heat treatment. Hot corrosion resistance increased for the specimens containing NiAl rather than Ni2Al3 phase. The ductile NiAl phase suppressed the potential for crack initiation during thermal cycling. Post heat treatment increased the corrosion resistance of the aluminized layer for Mar-M247, which underwent surface modification at 1273 K and above. In the boroaluminized Mar-M247 specimens, corrosion resistance decreased as a result of the blocking of outward diffusion of Cr by boron and decreased cohesion between the oxide scale and the aluminized layer during thermal cycling.

  13. Diamond film by hot filament CVD method

    NASA Technical Reports Server (NTRS)

    Hirose, Y.

    1988-01-01

    Diamond synthesis by the hot filament CVD method is discussed. A hot filament decomposes gas mixtures and oxygen containing organic compounds such as alcohols. which are carbon sources. The resulting thin films, growth mechanisms, and characteristics and problems associated with the hot filament CVD method are analyzed and evaluated.

  14. Weldability of high toughness Fe-12% Ni alloys containing Ti, Al or Nb

    NASA Technical Reports Server (NTRS)

    Devletian, J. H.; Stephens, J. R.; Witzke, W. R.

    1977-01-01

    Three exceptionally high-toughness Fe-12%Ni alloys designed for cryogenic service were welded using the GTA welding process. Evaluation of weldability included equivalent energy (KIed) fracture toughness tests, transverse-weld tensile tests at -196 and 25 C and weld crack sensitivity tests. The Fe-12%Ni-0.25%Ti alloy proved extremely weldable for cryogenic applications, having weld and HAZ properties comparable with those of the wrought base alloy. The Fe-12%Ni-0.5%Al had good weld properties only after the weld joint was heat treated. The Fe-12%Ni-0.25%Nb alloy was not considered weldable for cryogenic use because of its poor weld joint properties at -196 C and its susceptibility to hot cracking.

  15. ZnNi data

    DTIC Science & Technology

    2014-11-01

    carried out HE testing and passed, so that issue is resolved Concern over dezincification Keith Legg 847-680-9420 klegg@rowantechnology.com http...of the Zn-Ni plating 417 SCMS /GUEA, BR&T and ES3 are currently reviewing past industry de-zincification studies  Initial findings show that the...corrosion electro- potential is consistent throughout the corrosion process 417 SCMS /GUEA, BR&T and ES3 will identify any addition testing that

  16. Hot-Corrosion Behavior of Thermal Barrier Coated DZ125 Superalloy Exposed to Atomized Seawater and Kerosene

    NASA Astrophysics Data System (ADS)

    Bai, Zhiming; Zhou, Le; Liang, Tianquan; Guo, Hongbo; Gong, Shengkai

    The bare superalloy DZ 125 alloy, the aluminide coated specimens and electron beam physical vapor deposited (EB-PVD) thermal barrier coating (TBC) consisting of yttria stabilizied zirconia (YSZ) topcoat and NiCoCrAlY bond coat specimens were exposed to atomized seawater and kerosene at 900°C and the cyclic hot-corrosion behaviors of the specimens were investigated. Disastrous spallation of the bare superalloy occurred within 50 h hot-corrosion. In contrast to this, after 100 h hot-corrosion, the average mass change for the aluminized and TBC coated specimens is 0.7 mg/cm2 and 0.63 mg/cm2, respectively, exhibiting excellent hot-corrosion resistance.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Hot atom chemistry and radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  2. 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.

  3. 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.

  4. Hot stars in globular clusters.

    NASA Astrophysics Data System (ADS)

    Moehler, S.

    Globular clusters are ideal laboratories to study the evolution of low-mass stars. In this review, I shall concentrate on two types of hot stars observed in globular clusters: horizontal branch stars and UV bright stars. The third type, the white dwarfs, are covered by Bono in this volume. While the morphology of the horizontal branch correlates strongly with metallicity, it has been known for a long time that one parameter is not sufficient to describe the diversity of observed horizontal branch morphologies. A veritable zoo of candidates for this elusive ``2{nd} parameter'' has been suggested over the past decades, and the most prominent ones will be briefly discussed here. Adding to the complications, diffusion is active in the atmospheres of hot horizontal branch stars, which makes their analysis much more diffcult. The latest twist along the horizontal branch was added by the recent discovery of an extension to hotter temperatures and fainter magnitudes, the so-called ``blue hook''. The evolutionary origin of these stars is still under debate. I shall also give a brief overview of our current knowledge about hot UV bright stars and use them to illustrate the adverse effects of selection bias.

  5. 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.

  6. 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.

  7. 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.

  8. Slip-cast and hot-solution infiltrated porous yttria stabilized zirconia (YSZ) supported tubular fuel cells

    NASA Astrophysics Data System (ADS)

    Hanifi, Amir Reza; Paulson, Scott; Torabi, Alireza; Shinbine, Alyssa; Tucker, Michael C.; Birss, Viola; Etsell, Thomas H.; Sarkar, Partha

    2014-11-01

    Hot solution infiltration was investigated as a flexible and rapid method to incorporate anode and cathode components into fully sintered, porous ceramic tubular templates for use as solid oxide fuel cells (SOFC). Composed of either a porous 8 mol% yttria-stabilized zirconia (YSZ) or 5 wt% NiO-YSZ support structure, a thin Ni-YSZ anode functional layer and an outer ca. 10 μm dense YSZ electrolyte, closed end tubes were first hot solution (ca. 100 °C) infiltrated on the inside with NiO-SDC (Sm0.2Ce0.8O1.9) to serve as the anode. Cathodes were either LSM (nominally La0.8Sr0.2MnO3+δ) infiltrated into a thin porous YSZ layer on the outer electrolyte surface, or an LSCF-GDC composite (Gd0.1Ce0.9O1.95-La0.6Sr0.4Co0.2Fe0.8O3-δ) on a thin GDC buffer layer. Although hot solution infiltration of the Ni, Ce and Sm salts into the anode support structure did not result in complete penetration (with the Ni contents in the tube wall ranging between 4 and 10 vol.%), well-sealed full cells produced power densities as high as 275, 196 and 153 mW cm-2 at 800, 750 and 700 °C, respectively. Hot solution infiltration of active SOFC electrode materials is thus shown to be a very flexible approach for the evaluation of their performance.

  9. Heavy-element abundance patterns in hot DA white dwarfs

    NASA Astrophysics Data System (ADS)

    Barstow, M. A.; Good, S. A.; Holberg, J. B.; Hubeny, I.; Bannister, N. P.; Bruhweiler, F. C.; Burleigh, M. R.; Napiwotzki, R.

    2003-05-01

    We present a series of systematic abundance measurements for 25 hot DA white dwarfs in the temperature range ~20 000-110 000 K, based on far-ultraviolet spectroscopy with the Space Telescope Imaging Spectrograph (STIS)/Goddard High Resolution Spectrograph (GHRS) on-board Hubble Space Telescope, IUE and FUSE. Using our latest heavy-element blanketed non-local thermodynamic equilibrium (non-LTE) stellar atmosphere calculations we have addressed the heavy-element abundance patterns, making completely objective measurements of abundance values and upper limits using a χ2 fitting technique to determine the uncertainties in the abundance measurements, which can be related to the formal upper limits in those stars where particular elements are not detected. We find that the presence or absence of heavy elements in the hot DA white dwarfs largely reflects what would be expected if radiative levitation is the supporting mechanism, although the measured abundances do not match the predicted values very well, as reported by other authors in the past. Almost all stars hotter than ~50 000 K contain heavy elements. For most of these the spread in element abundances is quite narrow and similar to the abundances measured in G191-B2B. However, there is an unexplained dichotomy at lower temperatures with some stars having apparently pure H envelopes and others having detectable quantities of heavy elements. The heavy elements present in these cooler stars are often stratified, lying in the outermost layers of the envelope. A few strong temperature/evolutionary effects are seen in the abundance measurements. There is a decreasing Si abundance with temperature, the N abundance pattern splits into two groups at lower temperature and there is a sharp decline in Fe and Ni abundance to zero, below ~50 000 K. When detected, the Fe and Ni abundances maintain an approximately constant ratio, close to the cosmic value of ~20. For the hottest white dwarfs observed by STIS, the strongest

  10. 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

  11. Computational Prediction of Hot Spot Residues

    PubMed Central

    Morrow, John Kenneth; Zhang, Shuxing

    2013-01-01

    Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues. PMID:22316154

  12. Assessment of the factors affecting protective alumina formation under hot corrosion conditions

    NASA Astrophysics Data System (ADS)

    Task, Michael Nathan

    In this study, the influence of microstructure, composition, and phase constitution on the Type I (900°C) and Type II (700°C) hot corrosion resistance of MCrAlY and β-NiAl base alloys was investigated. The Type II hot corrosion resistance of MCrAlY alloys is generally enhanced by microstructural refinement. This can be attributed to the more rapid establishment of a protective Al2O3-rich scale due to the higher density of short-circuit diffusion paths for Al (phase boundaries). However, it was shown that for a given bulk composition, the compositions of the individual phases is also extremely important. If one phase is lean in an element which is highly beneficial from a hot corrosion standpoint, e.g., Cr, Type II hot corrosion resistance is quite poor, regardless of the microstructural scale. In addition, coarse reactive-element-rich phases, which are commonly found in MCrAlY alloys, can be incorporated into the thermally grown Al2O 3 scale and act as initiation sites for Type II attack. This stresses the importance of reactive element content and distribution in MCrAlY coatings. During Type I hot corrosion exposure of β-Ni-36Al (at. %) base alloys, the incubation stage is greatly extended by the addition of 5% Pt, Co, or Cr. In each case, the beneficial effects can be linked to an enhanced ability to rapidly form a protective Al2O3 scale, and to heal this scale when it sustains damage during exposure. With regard to Type II hot corrosion, individual additions of 5 at. % Pt or Cr are beneficial, largely for the same reason; however, additions of 5 at. % Co and co-additions of 5 at. % Pt + 5 at. % Cr result in a decrease in the duration of the incubation stage. Subsurface phase transformations that occur in the latter systems prevent the alloy from maintaining the growth of the Al2O3 scale. This mechanism is discussed in detail. Finally, the influence of alloy composition and exposure environment on the kinetics of the θ→α Al2O3 transformation in scales

  13. (001) Oriented piezoelectric films prepared by chemical solution deposition on Ni foils

    SciTech Connect

    Yeo, Hong Goo Trolier-McKinstry, Susan

    2014-07-07

    Flexible metal foil substrates are useful in some microelectromechanical systems applications including wearable piezoelectric sensors or energy harvesters based on Pb(Zr,Ti)O₃ (PZT) thin films. Full utilization of the potential of piezoelectrics on metal foils requires control of the film crystallographic texture. In this study, (001) oriented PZT thin films were grown by chemical solution deposition (CSD) on Ni foil and Si substrates. Ni foils were passivated using HfO₂ grown by atomic layer deposition in order to suppress substrate oxidation during subsequent thermal treatment. To obtain the desired orientation of PZT film, strongly (100) oriented LaNiO₃ films were integrated by CSD on the HfO₂ coated substrates. A high level of (001) LaNiO₃ and PZT film orientation were confirmed by X-ray diffraction patterns. Before poling, the low field dielectric permittivity and loss tangents of (001) oriented PZT films on Ni are near 780 and 0.04 at 1 kHz; the permittivity drops significantly on poling due to in-plane to out-of-plane domain switching. (001) oriented PZT film on Ni displayed a well-saturated hysteresis loop with a large remanent polarization ~36 μC/cm², while (100) oriented PZT on Si showed slanted P-E hysteresis loops with much lower remanent polarizations. The |e{sub 31,f}| piezoelectric coefficient was around 10.6 C/m² for hot-poled (001) oriented PZT film on Ni.

  14. Radiopaque Shape Memory Alloys: NiTi-Er with Stable Superelasticity

    NASA Astrophysics Data System (ADS)

    Tuissi, Ausonio; Carr, Shane; Butler, James; Gandhi, Abbasi A.; O'Donoghue, Lisa; McNamara, Karrina; Carlson, James M.; Lavelle, Shay; Tiernan, Peter; Biffi, Carlo A.; Bassani, Paola; Tofail, Syed A. M.

    2016-06-01

    Binary NiTi alloy is one of the most important biomaterials currently used in minimally invasive procedures and indwelling devices. The poor visibility of intermetallic NiTi under X-ray could be an unsatisfactory feature especially for developing low-dimensional implantable devices for the body. It is a matter of fact that the alloying of a third radiopaque element, such as noble or heavy metals, in NiTi can significantly enhance the alloy's radiopacity. Recently, it was demonstrated that the addition of a rare earth element such as Erbium has led to an equivalent radiopacity at a much lower cost than the equivalent addition of noble metals. This work reviews the main physical aspects related to the radiopacity of NiTi alloys and compares the radiopacity of NiTi-Er compositions with other NiTi-based alloys containing Pd, Pt, W and Cr. Furthermore, a NiTi-6Er alloy is produced by spark plasma sintering, and successfully processed by conventional hot and cold working procedures to a continuous wire showing stable superelastic behaviour (up to 4 % in strain), suitable for developing biomedical devices.

  15. Unconventional resistivity at the border of metallic antiferromagnetism in NiS2

    NASA Astrophysics Data System (ADS)

    Niklowitz, P. G.; Alireza, P. L.; Steiner, M. J.; Lonzarich, G. G.; Braithwaite, D.; Knebel, G.; Flouquet, J.; Wilson, J. A.

    2008-03-01

    We report low-temperature and high-pressure measurements of the electrical resistivity ρ(T) of the antiferromagnetic compound NiS2 in its high-pressure metallic state. The form of ρ(T,p) suggests the presence of a quantum phase transition at a critical pressure pc=76±5kbar . Near pc , the temperature variation of ρ(T) is similar to that observed in NiS2-xSex near the critical composition x=1 , where metallic antiferromagnetism is suppressed at ambient pressure. In both cases, ρ(T) varies approximately as T1.5 over a wide range below 100K . This lets us assume that the high-pressure metallic phase of stoichiometric NiS2 also develops itinerant antiferromagnetism, which becomes suppressed at pc . However, on closer analysis, the resistivity exponent in NiS2 exhibits an undulating variation with temperature not seen in NiSSe (x=1) . This difference in behavior may be due to the effects of spin-fluctuation scattering of charge carriers on cold and hot spots of the Fermi surface in the presence of quenched disorder, which is higher in NiSSe than in stoichiometric NiS2 .

  16. Oxidation and Hot Corrosion Behavior of Plasma-Sprayed MCrAlY-Cr2O3 Coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Tiantian; Huang, Chuanbing; Lan, Hao; Du, Lingzhong; Zhang, Weigang

    2016-08-01

    The oxidation and hot corrosion behavior of two atmospheric plasma-sprayed NiCoCrAlY-Cr2O3 and CoNiCrAlY-Cr2O3 coatings, which are primarily designed for wear applications at high temperature, were investigated in this study. The two coatings were exposed to air and molten salt (75%Na2SO4-25%NaCl) environment at 800 °C under cyclic conditions. Oxidation and hot corrosion kinetic curves were obtained by thermogravimetric technique. X-ray diffraction analysis and scanning electron microscopy with energy-dispersive x-ray spectrometry were employed to characterize the coatings' microstructure, surface oxides, and composition. The results showed that both coatings provided the necessary oxidation resistance with oxidation rates of about 1.03 × 10-2 and 1.36 × 10-2 mg/cm2 h, respectively. The excellent oxidation behavior of these two coatings is attributed to formation of protective (Ni,Co)Cr2O4 spinel on the surface, while as-deposited Cr2O3 in the coatings also acted as a barrier to diffusion of oxidative and corrosive substances. The greater presence of Co in the CoNiCrAlY-Cr2O3 coating restrained internal diffusion of sulfur and slowed down the coating's degradation. Thus, the CoNiCrAlY-Cr2O3 coating was found to be more protective than the NiCoCrAlY-Cr2O3 coating under hot corrosion condition.

  17. A Study of Thermo-mechanically Processed High Stiffness NiTiCo Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Manjeri, R. M.; Norwich, D.; Sczerzenie, F.; Huang, X.; Long, M.; Ehrlinspiel, M.

    2016-03-01

    This work investigates a vacuum induction melted-vacuum arc re-melted (VIM-VAR) and thermo-mechanically processed ternary NiTiCo shape memory alloy. The NiTiCo ingot was hot processed to 6.35-mm-diameter coiled wire. The coiled wire was subsequently cold drawn to a final wire diameter of 0.53 mm, with interpass anneals. The wires were shape set at 450 °C for 3.5 min. After electropolishing, the wires were subjected to microstructural, thermal, and mechanical characterization studies. Microstructural analysis was performed by transmission electron microscope (TEM), thermal analyses by differential scanning calorimeter (DSC), and bend-free recovery and mechanical testing by uniaxial tensile testing. TEM did not reveal Ni-rich precipitates—either at the grain boundary or in the grain interior. Energy dispersive x-ray spectroscopy showed a uniform distribution of Ni, Ti, and Co in the sample. The DSC results on the shape set wire showed a single-step transformation between the austenite and the R-phase, in the forward and reverse directions. Cyclic tensile tests of the shape set wire, processed under optimum conditions, showed minimum residual strain and a stable upper plateau stress. Further, the fatigue behavior of NiTi and NiTiCo alloys was studied by rotating beam testing. The results showed that the fatigue properties of NiTiCo, under zero mean strain, are equivalent to that of binary NiTi in the high-cycle and medium-cycle regimes, taking into account the higher stiffness of NiTiCo. The above analyses helped in establishing the processing-structure-property correlation in a VIM-VAR-melted NiTiCo shape memory alloy.

  18. Shape-memory NiTi with two-dimensional networks of micro-channels.

    PubMed

    Neurohr, Anselm J; Dunand, David C

    2011-04-01

    A process was developed for fabricating arrays of micro-channels in shape-memory NiTi for bone implant applications, with a tailorable internal architecture expected to improve biomechanical compatibility and osseointegration. Ni-51.4 at.% Ti with 24-34 vol.% porosity was fabricated by electrochemical dissolution of parallel layers of steel wire meshes embedded within a NiTi matrix during hot pressing of NiTi powders. The resulting NiTi structures exhibit parallel layers of orthogonally interconnected micro-channels with 350-400 μm diameters that exactly replicate the steel meshes. When low-carbon steel wires are used, iron diffuses into the surrounding NiTi during the densification step, creating a Fe-enriched zone near the wires. For high-carbon steel wires, TiC forms at the steel/NiTi interface and inhibits iron diffusion but also depletes some titanium from the adjacent NiTi. In both cases, the NiTi regions near the micro-channels exhibit altered phase transformation characteristics. These NiTi structures with replicated networks of micro-channels have excellent potential as bone implants and scaffolds given: (i) the versatility in channel size, shape, fraction and spatial arrangement; (ii) their low stiffness (15-26 GPa), close to 12-17 GPa for cortical bone; (iii) their high compressive strength (420-600 MPa at 8-9% strain); and (iv) their excellent compressive strain recovery (91-94% of an applied strain of 6%) by a combination of elasticity, superelasticity and the shape-memory effect.

  19. Microstructure and thermal conductivity of surfactant-free NiO nanostructures

    SciTech Connect

    Sahoo, Pranati; Misra, Dinesh K.; Salvador, Jim; Makongo, Julien P.A.; Chaubey, Girija S.; Takas, Nathan J.; Wiley, John B.; Poudeu, Pierre F.P.

    2012-06-15

    High purity, nanometer sized surfactant-free nickel oxide (NiO) particles were produced in gram scale using a solution combustion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), gas pycnometry and gas adsorption analysis (BET). The average particle size of the as-synthesized NiO increases significantly with the preheating temperature of the furnace, while the specific surface area decreases. A BET specific surface area of {approx}100 m{sup 2}/g was obtained for NiO nanoparticles with size as small as 3 nm synthesized at 300 Degree-Sign C. The thermal conductivity ({kappa}) of pressed pellets of the synthesized NiO nanoparticles obtained using spark plasma sintering (SPS) and uniaxial hot pressing is drastically decreased ({approx}60%) compared to that of NiO single crystal. This strong reduction in {kappa} with particle size suggests the suitability of the synthesized surfactant-free NiO nanoparticles for use as nanoinclusions when designing high performance materials for waste heat recovery. - Graphical abstract: Highly efficient phonon scattering by surfactant-free NiO nanostructures obtained by solution combustion of a mixture of nickel (II) nitrate hexahydrate (oxidizer) and urea (fuel) at various temperatures. Highlights: Black-Right-Pointing-Pointer Fast synthesis of surfactant-free NiO nanoparticles with controllable size. Black-Right-Pointing-Pointer High specific surface area for NiO nanoparticles with size range from 3 to 7 nm. Black-Right-Pointing-Pointer Strong reduction of the thermal conductivity with decreasing particle size. Black-Right-Pointing-Pointer NiO as nanoinclusions in high performance materials for energy conversion.

  20. Elevated Temperature Compressive Strength Properties of Oxide Dispersion Strengthened NiAl After Cryo-milling and Roasting in Nitrogen

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Grahle, Peter; Arzt, Eduard; Hebsur, Mohan

    1998-01-01

    In an effort to superimpose two different elevated temperature strengthening mechanisms in NiAl, several lots of oxide dispersion strengthened (ODS) NiAl powder have been cryo-milled in liquid nitrogen to introduce AlN particles at the grain boundaries. As an alternative to cryo-milling, one lot of ODS NiAl was roasted in nitrogen to produce AlN. Both techniques resulted in hot extruded AlN-strengthened, ODS NiAl alloys which were stronger than the base ODS NiAl between 1200 and 1400 K. However, neither the cryo-milled nor the N2-roasted ODS NiAl alloys were as strong as cryo-milled binary NiAl containing like amounts of AlN. The reason(s) for the relative weakness of cryo-milled ODS NiAl is not certain; however the lack of superior strength in N2-roasted ODS NiAl is probably due to its relatively large AlN particles.

  1. Enhanced thermoelectric properties of Co1- x- y Ni x+ y Sb3- x Sn x materials

    NASA Astrophysics Data System (ADS)

    Liu, Hong-Quan; Zhang, Sheng-Nan; Zhu, Tie-Jun; Zhao, Xin-Bing; Gu, Yi-Jie; Cui, Hong-Zhi

    2012-03-01

    Co1- x- y Nix+ y Sb3- x Sn x polycrystals were fabricated by vacuum melting combined with hot-press sintering. The effect of alloying on the thermoelectric properties of unfilled skutterudite Co1- x Ni x Sb3- x Sn x was investigated. A leap of electrical conductivity from the Co0.93Ni0.07Sb2.93Sn0.07 sample to the Co0.88Ni0.12Sb2.88Sn0.12 sample occurs during the measurement of electrical conductivity, indicating the adjustment of band structure by proper alloying. The results show that alloying enhances the power factor of the materials. On the basis of alloying, the thermoelectric properties of Co0.88Ni0.12Sb2.88Sn0.12 are improved by Ni-doping. The thermal conductivities of Ni-doping samples have no reduction, but their power factors have obvious enhancement. The power factor of Co0.81Ni0.19Sb2.88Sn0.12 reaches 3.0 mW·m-1·K-2 by Ni doping. The dimensionless thermoelectric figure of merit reaches 0.55 at 773 K for the unfilled Co0.81Ni0.19 Sb2.88Sn0.12.

  2. Comparison of Inclusions in Cold Drawn Wire and Precursor Hot-Rolled Rod Coil in VIM-VAR Nickel-Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Sczerzenie, Frank; Paul, Graeme; Belden, Clarence

    2011-07-01

    Inclusion content is important for the mechanical behavior and performance of Nitinol wires, particularly in fatigue-rated devices. The purpose of this work was to make a quantitative comparison between inclusion populations in cold drawn wires and the precursor populations in hot-rolled rod coil. Inclusion content was examined in a series of VIM-VAR alloys with different transformation temperatures (TTR) controlled by the Ni to Ti ratio. This range of chemistry was chosen to assess the effect of Ni to Ti ratio on inclusion formation. In order to understand the differences in behavior between carbides and intermetallic oxides in wire drawing, carbides, and intermetallic oxide inclusions were measured separately using optical metallography pursuant to ASTM F2063. In VIM-VAR alloys at higher Ni to Ti ratios about 50.79 a/o Ni the formation of intermetallic oxides appears to be suppressed in the as-cast material through the presence of carbon and the precipitation of eutectic TiC in place of eutectic Ti4Ni2O x . The structure of VIM-VAR alloy also varies after hot working depending on the TTR of the alloy. Higher TTR binary alloys with lower Ni to Ti ratios tend to have more and larger intermetallic oxides and fewer and smaller carbides after hot working. Microsegregation plays a role in inclusion formation. That is, during solidification, C, O, N diffuse to the interdendritic regions. This increases the potential for the precipitation of nonmetallic species. Carbides and intermetallic oxides behave differently in hot working and cold drawing. The change in maximum carbide size from coil to wire is very near zero for all Ni to Ti ratios. The change in maximum inclusion size from coil to wire is driven mainly by the fracture of intermetallic oxides and the formation of intermetallic oxide stringers.

  3. Imaging Chemical Aggregation of Ni/NiO Particles from Reduced NiO-YSZ

    SciTech Connect

    Saraf, Laxmikant V.

    2011-07-20

    Energy dispersive X-ray spectroscopy (EDS) mapping of nickel oxide yttria-stabilized zirconia (NiO-YSZ) was carried out after various hydrogen reducing and methane steam reforming conditions. Nickel aggregation was visualized after methane steam reforming by correlating Ni K{sub {alpha}} map with scanning transmission electron microscopy (STEM) images. From the reduced O K{sub {alpha}} intensities in the Ni K{sub {alpha}} dominated regions after methane steam reforming, NiO reduction in to Ni can be interpreted. From correlation between Zr K{sub {alpha}} and O K{sub {alpha}} maps, high stability of YSZ was also realized. Examples of NiO-YSZ overlapped particles are considered to discuss chemical imaging of a single particle.

  4. Effects of surface chemistry on hot corrosion life

    NASA Technical Reports Server (NTRS)

    Fryxell, R. E.

    1985-01-01

    Burner rig tests were conducted under the following conditions: 900 C, hourly thermal cycling, 0.5 ppm sodium as MaCl in the gas stream, velocity 0.3 Mach. The alloys are Udiment 700, Rene 80, uncoated and with RT21, Codep, or NiCoCrAlY coatings. These tests were completed for specimens in the as-processed condition and after aging at 1100 C in oxidizing or inert evnivronments for time up to 600 hours. Coil inductance changes used for periodic nondestructive inspection of specimens were useful in following the course of corrosion. Typical sulfidation was observed in all cases, structurally similar to that observed for service-run turbine components. Aging at cuased a severe decrease in hot corrosion life of RT21 and Codep coatings and a significant but less decrease in the life of the NiCoCrAlY coating. The extent of these decreases was much greater for all three coatings on U700 substrates than on Rene 80 substrates. Coating/substrate interdiffusion rather than by surface oxidation.

  5. A hot-atom reaction kinetic model for H abstraction from solid surfaces

    NASA Astrophysics Data System (ADS)

    Kammler, Th.; Kolovos-Vellianitis, D.; Küppers, J.

    2000-07-01

    Measurements of the abstraction reaction kinetics in the interaction of gaseous H atoms with D adsorbed on metal and semiconductor surfaces, H(g)+D(ad)/S→ products, have shown that the kinetics of the HD products are at variance with the expectations drawn from the operation of Eley-Rideal mechanisms. Furthermore, in addition to HD product molecules, D 2 products were observed which are not expected in an Eley-Rideal scenario. Products and kinetics of abstraction reactions on Ni(100), Pt(111), and Cu(111) surfaces were recently explained by a random-walk model based solely on the operation of hot-atom mechanistic steps. Based on the same reaction scenario, the present work provides numerical solutions of the appropriate kinetic equations in the limit of the steady-state approximation for hot-atom species. It is shown that the HD and D 2 product kinetics derived from global kinetic rate constants are the same as those obtained from local probabilities in the random walk model. The rate constants of the hot-atom kinetics provide a background for the interpretation of measured data, which was missing up to now. Assuming that reconstruction affects the competition between hot-atom sticking and hot-atom reaction, the application of the present model at D abstraction from Cu(100) surfaces reproduces the essential characteristics of the experimentally determined kinetics.

  6. Effect of a chromium-containing fuel additive on hot corrosion

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    Four cast superalloys (one cobalt-base and three nickel-base) were tested at 900 C for 100 h in Mach 0.3 combustion gases. 5 ppm of synthetic sea salt were added to the gases in the combustion chamber. Several types of thermal cycle and washing procedures were employed. Similar tests were made with the addition of 300 ppm of a chromium-containing fuel additive. In both sets of tests the extent of hot corrosion was evaluated by specific weight change and metal recession. In general, the chromium additive in the fuel reduced the extent of hot (salt) corrosion but did not eliminate it. The percentage reduction of hot corrosion attack was similar for all four alloys. As great a reduction of hot corrosion was achieved by reducing the number of thermal cycles during the test from 100 to 5 or 6. The effect of washing the alloys every ten cycles as opposed to the end of the test was erratic; some alloys were attacked slightly more, others somewhat less. A NiCrAlY coating was found to be more effective in reducing hot corrosion than either the fuel additive or the washing schedule.

  7. Deformation and Fracture Testing for Hot Working Processes

    NASA Astrophysics Data System (ADS)

    Fitzsimons, G.; Kuhn, H. A.; Venkateshwar, R.

    1981-05-01

    A hot workability testing apparatus has been designed and constructed for determining flow stress and fracture of materials at elevated temperatures. The system is composed of four major elements: a closed-loop servo-controlled hydraulic testing machine with programmable and custom-made control components; a high temperature tooling and radiant heating furnace for isothermal test conditions; a test specimen transfer device for ease of testing and rapid quenching; and a computerized data acquisition and reduction system. Isothermal, homogeneous compression tests are performed for flow stress determination, while upset and bend tests are used for workability evaluation. Test temperatures to 1200°C may be achieved, along with constant strain rates up to 20s'1 for both compression and bend tests. Specimens can be quenched within 0.5-0.75s to permit the study of the microstructures developed during hot deformation. In both compression and bending, interrupted deformation schedules can be programmed. Change of rate tests to measure strain rate sensitivites are also possible. Capabilities of the system are illustrated by results obtained for the multiphase alloy MP35N (35% Co, 35% Ni, 20%o Cr, and 10% Mo).

  8. "Hotness" stability of chicken hot-wing products as affected by preparation methods and storage.

    PubMed

    Chang, M H; Chen, T C

    1998-04-01

    Chicken hot-drumettes containing 2% cayenne pepper were prepared using three different cooking methods and stored under two different temperatures for "hotness" evaluation. Results demonstrated that the hotness of the samples were highest when products were cooked in a microwave oven, followed by convection oven, and least hot by deep-fat frying. Regardless of the cooking method, the degree of hotness of the hot-drumette decreased drastically during refrigerated storage. Results also indicated that the loss of hotness was associated with the increase of 2-thiobarbituric acid (TBA) values in the product. The addition of antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), rosemary, and sodium nitrate during preparation or vacuum packaging retarded lipid oxidation of chicken hot-drumettes and retarded the loss of hotness of the products during refrigerated storage.

  9. Metal Temperature Evaluation Method Based on Microstructure Change of Ni Based Superalloy

    NASA Astrophysics Data System (ADS)

    Okada, Ikuo; Taneike, Masaki; Oguma, Hidetaka

    It is known that among numerous factors, industrial turbine Inlet gas Temperature (TIT, hereafter) has greatest influence on thermal efficiency of industrial gas turbine. In order to achieve higher thermal efficiency, TIT has already reached as high as 1500°C, which has been realized owing to improvement and development of cooling configuration and materials for hot parts. On the other hand, to operate gas turbines soundly, it is necessary to evaluate metal temperature of hot parts precisely. So, metal temperature evaluation methods of Ni base superalloy were investigated and developed based on coarsening phenomenon of γ' phase and carbide particles.

  10. 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.

  11. 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.

  12. Emissions Reductions Associated with the Use of Warm-Mix Asphalt as Compared to Hot-Mix Asphalt

    DTIC Science & Technology

    2014-06-01

    gas, light fuel oils, or waste fuel oils and its sulfur content (NPI 1999). In counter-flow drum-mix plants, the liquid asphalt , aggregate, and...ER D C/ G SL T R- 14 -1 9 Emissions Reductions Associated with the Use of Warm-Mix Asphalt as Compared to Hot-Mix Asphalt G eo te ch ni...Reductions Associated with the Use of Warm-Mix Asphalt as Compared to Hot-Mix Asphalt Mariely Mejías-Santiago Geotechnical and Structures

  13. 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

  14. Hot, Rocky World Artist Concept

    NASA Image and Video Library

    2015-07-30

    This artist's rendition shows one possible appearance for the planet HD 219134b, the nearest confirmed rocky exoplanet found to date outside our solar system. The planet is 1.6 times the size of Earth, and whips around its star in just three days. Scientists predict that the scorching-hot planet -- known to be rocky through measurements of its mass and size -- would have a rocky, partially molten surface with geological activity, including possibly volcanoes. http://photojournal.jpl.nasa.gov/catalog/PIA19833

  15. 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.

  16. Subminiature Hot-Wire Probes

    NASA Technical Reports Server (NTRS)

    Westphal, R. V.; Lemos, F. R.; Ligrani, P. M.

    1989-01-01

    Class of improved subminiature hot-wire flow-measuring probes developed. Smaller sizes yield improved resolution in measurements of practical aerodynamic flows. Probe made in one-wire, two-perpendicular-wire, and three-perpendicular-wire version for measurement of one, two, or all three components of flow. Oriented and positioned on micromanipulator stage and viewed under microscope during fabrication. Tested by taking measurements in constant-pressure turbulent boundary layer. New probes give improved measurements of turbulence quantities near surfaces and anisotropies of flows strongly influence relative errors caused by phenomena related to spatial resolution.

  17. 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.

  18. Breakup Densities of Hot Nuclei

    NASA Astrophysics Data System (ADS)

    Viola, V. E.; Kwiatkowski, K.; Natowitz, J. B.; Yennello, S. J.

    2004-09-01

    Breakup densities of hot 197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E*/A≲2 MeV, followed by a gradual decrease to a near-constant value of ρ/ρ0˜0.3 for E*/A≳5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios.

  19. 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.

  20. Reactive Ni/Ti nanolaminates

    SciTech Connect

    Adams, D. P.; Bai, M. M.; Rodriguez, M. A.; McDonald, J. P.; Jones, E. Jr.; Brewer, L.; Moore, J. J.

    2009-11-01

    Nickel/titanium nanolaminates fabricated by sputter deposition exhibited rapid, high-temperature synthesis. When heated locally, self-sustained reactions were produced in freestanding Ni/Ti multilayer foils characterized by average propagation speeds between approx0.1 and 1.4 m/s. The speed of a propagating reaction front was affected by total foil thickness and bilayer thickness (layer periodicity). In contrast to previous work with compacted Ni-Ti powders, no preheating of Ni/Ti foils was required to maintain self-propagating reactions. High-temperature synthesis was also stimulated by rapid global heating demonstrating low ignition temperatures (T{sub ig})approx300-400 deg. C for nanolaminates. Ignition temperature was influenced by bilayer thickness with more coarse laminate designs exhibiting increased T{sub ig}. Foils reacted in a vacuum apparatus developed either as single-phase B2 cubic NiTi (austenite) or as a mixed-phase structure that was composed of monoclinic B19{sup '} NiTi (martensite), hexagonal NiTi{sub 2}, and B2 NiTi. Single-phase, cubic B2 NiTi generally formed when the initial bilayer thickness was made small.

  1. Atomic diffusion in liquid Ni, NiP, PdNiP, and PdNiCuP alloys

    SciTech Connect

    Chathoth, S. Mavila; Meyer, A.; Koza, M.M.; Juranyi, F.

    2004-11-22

    We investigated the self-diffusion of Ni in liquid Ni, Ni{sub 80}P{sub 20}, Pd{sub 40}Ni{sub 40}P{sub 20}, and Pd{sub 43}Ni{sub 10}Cu{sub 27}P{sub 20} at temperatures up to 1795 K with incoherent, quasielastic neutron scattering. Values of measured self-diffusion coefficients vary over the accessible temperature ranges as a function of composition only within 10%. Although mixing has a drastic effect on the liquidus temperature and the undercooling capabilities, a relation between these properties and the atomic diffusion in the liquid is not observed. Apparently, diffusive motion is governed by the packing fraction of the atoms, that is very similar in these dense liquids.

  2. Atmospheric Dynamics of Hot Exoplanets

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; Showman, Adam P.

    2015-05-01

    The characterization of exoplanetary atmospheres has come of age in the past decade, as astronomical techniques now allow for albedos, chemical abundances, temperature profiles and maps, rotation periods, and even wind speeds to be measured. Atmospheric dynamics sets the background state of density, temperature, and velocity that determines or influences the spectral and temporal appearance of an exoplanetary atmosphere. Hot exoplanets are most amenable to these characterization techniques. In this review, we focus on highly irradiated, large exoplanets (the hot Jupiters), as astronomical data begin to confront theoretical questions. We summarize the basic atmospheric quantities inferred from the astronomical observations. We review the state of the art by addressing a series of current questions, and look toward the future by considering a separate set of exploratory questions. Attaining the next level of understanding requires a concerted effort of constructing multifaceted, multiwavelength datasets for benchmark objects. Understanding clouds presents a formidable obstacle, as they introduce degeneracies into the interpretation of spectra, yet their properties and existence are directly influenced by atmospheric dynamics. Confronting general circulation models with these multifaceted, multiwavelength datasets will help us understand these and other degeneracies.

  3. Abundances in Hot Evolved Stars

    NASA Astrophysics Data System (ADS)

    Werner, Klaus; Rauch, Thomas; Kruk, Jeffrey W.

    2009-05-01

    The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell region. Thus, the photospheric element abundances of these stars allow us to draw conclusions about details of nuclear burning and mixing processes in the precursor AGB stars. We compare predicted element abundances to those determined by quantitative spectral analyses performed with advanced non-LTE model atmospheres. A good qualitative and quantitative agreement is found for many species (He, C, N, O, Ne, F, Si, Ar) but discrepancies for others (P, S, Fe) point at shortcomings in stellar evolution models for AGB stars. Almost all of the chemical trace elements in these hot stars can only be identified in the UV spectral range. The Far Ultraviolet Spectroscopic Explorer and the Hubble Space Telescope played a crucial role for this research.

  4. Menopausal Hot Flashes and White Matter Hyperintensities

    PubMed Central

    Thurston, Rebecca C.; Aizenstein, Howard J.; Derby, Carol A.; Sejdić, Ervin; Maki, Pauline M.

    2015-01-01

    Objective Hot flashes are the classic menopausal symptom. Emerging data links hot flashes to cardiovascular disease (CVD) risk, yet how hot flashes are related to brain health is poorly understood. We examined the relationship between hot flashes - measured via physiologic monitor and self-report - and white matter hyperintensities (WMH) among midlife women. Methods Twenty midlife women ages 40-60 without clinical CVD, with their uterus and both ovaries, and not taking hormone therapy were recruited. Women underwent 24 hours of ambulatory physiologic and diary hot flash monitoring to quantify hot flashes; magnetic resonance imaging to assess WMH burden; 72 hours of actigraphy and questionnaires to quantify sleep; and a blood draw, questionnaires, and physical measures to quantify demographics and CVD risk factors. Test of a priori hypotheses regarding relations between physiologically-monitored and self-reported wake and sleep hot flashes and WMH were conducted in linear regression models. Results More physiologically-monitored hot flashes during sleep were associated with greater WMH, controlling for age, race, and body mass index [beta(standard error)=.0002 (.0001), p=.03]. Findings persisted controlling for sleep characteristics and additional CVD risk factors. No relations were observed for self-reported hot flashes. Conclusions More physiologically-monitored hot flashes during sleep were associated with greater WMH burden among midlife women free of clinical CVD. Results suggest that relations between hot flashes and CVD risk observed in the periphery may extend to the brain. Future work should consider the unique role of sleep hot flashes in brain health. PMID:26057822

  5. The Hybrid Orthodontic Treatment System (HOTS).

    PubMed

    Ikegami, Tomio; Wong, Ricky Wing-Kit; Hägg, Urban; Lee, Wilson; Hibino, Kyoko

    2010-01-01

    This paper describes the Hybrid Orthodontic Treatment System (HOTS), an innovative method used in first premolar extraction cases. It comprises the following three components: (1) a miniscrew, (2) dual-dimension wires, and (3) multiloop edgewise archwires. HOTS consists of four clearly defined treatment steps: (1) setup, (2) leveling, (3) separate but simultaneous anterior and canine teeth retraction, and (4) final adjustment. HOTS achieves a predictable treatment outcome with a shorter treatment time.

  6. Hot Workability of CuZr-Based Shape Memory Alloys for Potential High-Temperature Applications

    NASA Astrophysics Data System (ADS)

    Biffi, Carlo Alberto; Tuissi, Ausonio

    2014-07-01

    The research on high-temperature shape memory alloys has been growing because of the interest of several potential industrial fields, such as automotive, aerospace, mechanical, and control systems. One suitable candidate is given by the CuZr system, because of its relative low price in comparison with others, like the NiTi-based one. In this context, the goal of this work is the study of hot workability of some CuZr-based shape memory alloys. In particular, this study addresses on the effect of hot rolling process on the metallurgical and calorimetric properties of the CuZr system. The addition of some alloying elements (Cr, Co, Ni, and Ti) is taken into account and their effect is also put in comparison with each other. The alloys were produced by means of an arc melting furnace in inert atmosphere under the shape of cigars. Due to the high reactivity of these alloys at high temperature, the cigars were sealed in a stainless steel can before the processing and two different procedures of hot rolling were tested. The characterization of the rolled alloys is performed using discrete scanning calorimetry in terms of evolution of the martensitic transformation and scanning electron microscopy for the microstructural investigations. Additionally, preliminary tests of laser interaction has been also proposed on the alloy more interesting for potential applications, characterized by high transformation temperatures and its good thermal stability.

  7. Comparison of benzene adsorption on Ni(111) and Ni(100)

    SciTech Connect

    Myers, A.K.; Schoofs, G.R.; Benziger, J.B.

    1987-04-23

    The adsorption of benzene on the Ni(100) and the Ni(111) crystal faces was compared in order to investigate the effect of crystallographic orientation on the interaction of benzene with nickel. Temperature programmed reaction (TPR) was used to characterize adsorption bond strengths and determine product distributions. Benzene was found to adsorb 44 kJ/mol less strongly on the Ni(111) plane than on the Ni(100) surface. Di-hydrogen evolution formed after decomposition of benzene was similar for both surfaces. Benzene chemisorption was modeled by using extended Hueckel theory (EHT), a semiempirical molecular orbital method. The calculations predict bonding of benzene over a threefold hollow site on Ni(111). Multicenter bonding of the benzene carbon atoms with the nickel atoms is indicated by the calculations. The binding strength of benzene is controlled by the degree of overlap of the carbon ..pi.. orbitals with the nickel atom orbitals. Benzene binds more strongly to the Ni(100) surface because the carbon ..pi.. orbitals can overlap with four nickel atoms on the fourfold hollow site, whereas on Ni(111) the carbon atoms are closely associated with only three nickel atoms on the threefold hollow site.

  8. 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.

  9. Hydrogen production by reforming of simulated hot coke oven gas over nickel catalysts promoted with lanthanum and cerium in a membrane reactor

    SciTech Connect

    Hongwei Cheng; Xionggang Lu; Yuwen Zhang; Weizhong Ding

    2009-05-15

    Catalysts of Ni/Mg(Al)O promoted with lanthanum and cerium were tested in a BaCo{sub 0.7}Fe{sub 0.2}Nb{sub 0.1}O{sub 3{delta}} (BCFNO) membrane reactor by catalytic partial oxidation of simulated hot coke oven gas (COG) with toluene as a model tar compound under atmospheric pressure. Analysis of the catalysts suggested that the hydrotalcite precursor after thermal treatment lead to a good dispersion of nickel forming the solid solution NiO-MgO and spinel (Ni,Mg)Al{sub 2}O{sub 4}. The promoted catalysts had higher oxygen permeation flux, better catalytic activity, and better resistance to carbon formation, which will be promising catalysts in the catalytic partial oxidation reforming of hot COG. 29 refs., 11 figs., 2 tabs.

  10. Investigation of vanadium and hot-corrosion resistance of chromium- and silicon-base coating systems. Semiannual report, 21 September 1980-31 March 1981

    SciTech Connect

    Barkalow, R.H.; Kahn, A.S.

    1981-04-01

    This program evaluated turbine coating materials for resisting hot corrosion and ash erosion effects due to V, S, and alkali metals in residual oils, and coal-derived fuels. Furnace and burner rig tests were conducted to evaluate the performance of NiCrSi alloys, NiCrSi alloys containing additives, Cr-base alloys, and Si-34Cr-23Ta in Na/sub 2/SO/sub 4/, V/sub 2/O/sub 5/ and mixed salt hot corrosion. CoCrAlY, Co-40Cr-8Si, and Cr-20Ni-5Mn-5Si were also evaluated. Tests in gaseous environments containing SO/sub 3/ are planned. 8 figures. (DLC)

  11. Highly conductive and low cost Ni-PET flexible substrate for efficient dye-sensitized solar cells.

    PubMed

    Su, Haijun; Zhang, Mingyang; Chang, Ya-Huei; Zhai, Peng; Hau, Nga Yu; Huang, Yu-Ting; Liu, Chang; Soh, Ai Kah; Feng, Shien-Ping

    2014-04-23

    The highly conductive and flexible nickel-polyethylene terephthalate (Ni-PET) substrate was prepared by a facile way including electrodeposition and hot-press transferring. The effectiveness was demonstrated in the counter electrode of dye-sensitized solar cells (DSSCs). The Ni film electrodeposition mechanism, microstructure, and DSSC performance for the Ni-PET flexible substrate were investigated. The uniform and continuous Ni film was first fabricated by electroplating metallic Ni on fluorine-doped tin oxide (FTO) and then intactly transferred onto PET via hot-pressing using Surlyn as the joint adhesive. The obtained flexible Ni-PET substrate shows low sheet resistance of 0.18Ω/□ and good chemical stability for the I(-)/I(3-) electrolyte. A high light-to-electric energy conversion efficiency of 7.89% was demonstrated in DSSCs system based on this flexible electrode substrate due to its high conductivity, which presents an improvement of 10.4% as compared with the general ITO-PEN flexible substrate. This method paves a facile and cost-effective way to manufacture various metals on a plastic nonconducive substrate beneficial for the devices toward flexible and rollable.

  12. Biomass Catalytic Pyrolysis on Ni/ZSM-5: Effects of Nickel Pretreatment and Loading

    DOE PAGES

    Yung, Matthew M.; Starace, Anne K.; Mukarakate, Calvin; ...

    2016-04-25

    Here in this work, Ni/ZSM-5 catalysts with varied nickel loadings were evaluated for their ability to produce aromatic hydrocarbons by upgrading of pine pyrolysis vapors. The effect of catalyst pretreatment by hydrogen reduction was also investigated. Results indicate that the addition of nickel increases the yield of aromatic hydrocarbons while simultaneously increasing the conversion of oxygenates, relative to ZSM-5, and these effects are more pronounced with increasing nickel loading. Additionally, while initial activity differences were observed between the oxidized and reduced forms of nickel on ZSM-5 (i.e., NiO/ZSM-5 versus Ni/ZSM-5), the activity of both catalysts converges with increasing time onmore » stream. These reaction results coupled with characterization of pristine and spent catalysts suggest that the catalysts reach similar active states during catalytic pyrolysis, regardless of pretreatment, as NiO undergoes in situ reduction to Ni by biomass pyrolysis vapors. This reduction of NiO to Ni was confirmed by reaction results and characterization by NH3 temperature-programmed desorption, temperature-programmed reduction, and X-ray diffraction. This finding is significant in that the ability to reduce or eliminate the need for a pre-reaction H2 reduction of Ni-modified zeolite catalysts could reduce process complexity and operating costs in a biorefinery-based vapor-phase upgrading process to produce biomass-derived fuels and chemicals. The ability to monitor catalyst activity in real time with a molecular beam mass spectrometer used to measure uncondensed, hot pyrolysis vapors allows for an improved understanding of the mechanism for improved activity with Ni addition to ZSM-5, which is attributed to the ability to prevent deactivation by deposition of coke and capping of zeolite micropores.« less

  13. Biomass Catalytic Pyrolysis on Ni/ZSM-5: Effects of Nickel Pretreatment and Loading

    SciTech Connect

    Yung, Matthew M.; Starace, Anne K.; Mukarakate, Calvin; Crow, Allison M.; Leshnov, Marissa A.; Magrini, Kimberly A.

    2016-04-25

    Here in this work, Ni/ZSM-5 catalysts with varied nickel loadings were evaluated for their ability to produce aromatic hydrocarbons by upgrading of pine pyrolysis vapors. The effect of catalyst pretreatment by hydrogen reduction was also investigated. Results indicate that the addition of nickel increases the yield of aromatic hydrocarbons while simultaneously increasing the conversion of oxygenates, relative to ZSM-5, and these effects are more pronounced with increasing nickel loading. Additionally, while initial activity differences were observed between the oxidized and reduced forms of nickel on ZSM-5 (i.e., NiO/ZSM-5 versus Ni/ZSM-5), the activity of both catalysts converges with increasing time on stream. These reaction results coupled with characterization of pristine and spent catalysts suggest that the catalysts reach similar active states during catalytic pyrolysis, regardless of pretreatment, as NiO undergoes in situ reduction to Ni by biomass pyrolysis vapors. This reduction of NiO to Ni was confirmed by reaction results and characterization by NH3 temperature-programmed desorption, temperature-programmed reduction, and X-ray diffraction. This finding is significant in that the ability to reduce or eliminate the need for a pre-reaction H2 reduction of Ni-modified zeolite catalysts could reduce process complexity and operating costs in a biorefinery-based vapor-phase upgrading process to produce biomass-derived fuels and chemicals. The ability to monitor catalyst activity in real time with a molecular beam mass spectrometer used to measure uncondensed, hot pyrolysis vapors allows for an improved understanding of the mechanism for improved activity with Ni addition to ZSM-5, which is attributed to the ability to prevent deactivation by deposition of coke and capping of zeolite micropores.

  14. Biomass Catalytic Pyrolysis on Ni/ZSM-5: Effects of Nickel Pretreatment and Loading

    SciTech Connect

    Yung, Matthew M.; Starace, Anne K.; Mukarakate, Calvin; Crow, Allison M.; Leshnov, Marissa A.; Magrini, Kimberly A.

    2016-04-25

    Here in this work, Ni/ZSM-5 catalysts with varied nickel loadings were evaluated for their ability to produce aromatic hydrocarbons by upgrading of pine pyrolysis vapors. The effect of catalyst pretreatment by hydrogen reduction was also investigated. Results indicate that the addition of nickel increases the yield of aromatic hydrocarbons while simultaneously increasing the conversion of oxygenates, relative to ZSM-5, and these effects are more pronounced with increasing nickel loading. Additionally, while initial activity differences were observed between the oxidized and reduced forms of nickel on ZSM-5 (i.e., NiO/ZSM-5 versus Ni/ZSM-5), the activity of both catalysts converges with increasing time on stream. These reaction results coupled with characterization of pristine and spent catalysts suggest that the catalysts reach similar active states during catalytic pyrolysis, regardless of pretreatment, as NiO undergoes in situ reduction to Ni by biomass pyrolysis vapors. This reduction of NiO to Ni was confirmed by reaction results and characterization by NH3 temperature-programmed desorption, temperature-programmed reduction, and X-ray diffraction. This finding is significant in that the ability to reduce or eliminate the need for a pre-reaction H2 reduction of Ni-modified zeolite catalysts could reduce process complexity and operating costs in a biorefinery-based vapor-phase upgrading process to produce biomass-derived fuels and chemicals. The ability to monitor catalyst activity in real time with a molecular beam mass spectrometer used to measure uncondensed, hot pyrolysis vapors allows for an improved understanding of the mechanism for improved activity with Ni addition to ZSM-5, which is attributed to the ability to prevent deactivation by deposition of coke and capping of zeolite micropores.

  15. The impact of phenomena El Niño and La Niña and other environmental factors on episodes of acute diarrhoea disease in the population of Aguascalientes, Mexico: a case study

    NASA Astrophysics Data System (ADS)

    Esthela Venegas-Pérez, Martha; Ramírez-López, Elsa Marcela; López-Santos, Armando; Orlando Magaña-Rueda, Víctor; Avelar-González, Francisco Javier

    2016-03-01

    Acute diarrhoea diseases (ADDs) are one of the major health problems in Aguascalientes, Mexico. Due to the risk of significant increases of ADDs in the hot season, it has been necessary to determine the weather conditions that might lead to escalating ADD events. The effects of El Niño and La Niña phenomena on the morbidity rate of ADD (MRADD) in the State of Aguascalientes were determined during the period of 2000-2010. The MRADD was calculated from cases reported by the State Health Department. The Oceanic Niño Index (ONI) was obtained from the US National Oceanic and Atmospheric Administration. The impact of El Niño and La Niña on the MRADD was determined using the Pearson correlation coefficient and analysis of variance (ANOVA). The results gave a significant inverse correlation between El Niño phenomenon and MRADD (r = -0.55, P = 0.001), but a correlation was not observed on the La Niña phenomenon (r = -0.022, P = 0.888). Field data showed significant inverse influence of El Niño on MRADD for the years 2000-2010.

  16. LACBED characterization of dislocations in Cu-Al-Ni shape memory alloys processed by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Rodriguez, P. P.; Ibarra, A.; San Jean, J.; Morniro, J. P.; No, M. L.

    2003-10-01

    Powder metallurgy Cu-AI-Ni shape memory alloys show excellent thermomechanical properties, being the fracture behavior close to the one observed in single crystals. However, the microstructural mechanisms responsible of such behavior are still under study. In this paper we present the characterization of the dislocations present in these alloys by Large Angle Convergent Beam Electron Diffraction (LACBED) in two different stages of the elaboration process: after HIP compaction and after hot rolling.

  17. Residual stress and fracture characteristics of zirconia/metal(Ni, SUS304) functionally gradient materials

    SciTech Connect

    Jung, Yeon-Gil; Choi, Sung-Churl; Paik, Un-Gyu

    1995-09-01

    To analyze the residual stress and the fracture behavior of FGMs. disc-type TZP/Ni- and TZP/SUS304-FGM were hot passed, and compared with MM& The continuous interface and the microstructure of FGMs were characterized with EPMA, optical microscopy and SEM. The defect-like cracks in the FGMs induced by the preferential shear stress have been shown to cause fracture. This fact has well corresponded to the analysis of the residual stress distribution by FEM.

  18. 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

  19. Menopausal hot flushes and vascular health.

    PubMed

    Tuomikoski, Pauliina; Ylikorkala, Olavi; Mikkola, Tomi S

    2011-06-01

    Hot flushes are complained of by approximately 75% of all postmenopausal women, and hormone therapy (HT) is the most effective way to alleviate them. Hot flushes are characterized by altered vascular function and sympathetic nervous system activity. Hot flushes occurred more often in women attending large, non-randomized observational studies (e.g. Nurses' Health Study), where HT use protected against cardiovascular disease (CVD). However, they were absent (or mild) in randomized HT trials where HT use was accompanied with an elevated risk for CVD. Hot flushes, if a factor for cardiovascular health, could partly explain the conflict between observational and randomized trials. Several cross-sectional studies imply that hot flushes are detrimental to the cardiovascular system. However, the data are not uniform, and hot flushes were recalled retrospectively or during HT use. In our prospective study hot flushes were accompanied with a vasodilatory effect during endothelial testing, and this was related to the severity of hot flushes. Night-time hot flushes were followed with transient rises in ambulatory blood pressure (BP). However, no effect of hot flushes on diurnal BP was detected. The use of estradiol showed no harmful effects on endothelial function in women with hot flushes, but in non-flushing women oral, but not transdermal, estradiol led to vasoconstrictive changes. Estradiol complemented with medroxyprogesterone acetate eliminated the vasoconstrictive effect of sole oral estradiol. Thus, both oral and transdermal estradiol are applicable in flushing women, whereas a transdermal route should be favored in non-flushing women if used e.g. for bone protection.

  20. 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.

  1. 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.

  2. Protective clothing in hot environments.

    PubMed

    Holmér, Ingvar

    2006-07-01

    The high level of protection required by personal protective clothing (PPC) severely impedes heat exchange by sweat evaporation. As a result work associated with wearing PPC, particularly in hot environments, implies considerable physiological strain and may render workers exhausted in a short time. Recent development of algorithms for describing the heat transfer, accounting for pumping and wind effects, comprises improvement of the prediction of thermal stress. Realistic corrections can then be made to the available measures of thermal insulation and evaporative resistance of a given clothing ensemble. Currently this information is incorporated in international standards for assessment of thermal environments. Factors, such as directional radiation and wetting of layers, were studied in a recently completed EU research project. The development of advanced thermal manikins and measurement procedures should provide better measures for predictive models. As with all methods and models, the results need validation in realistic wear trials in order to prove their relevance and accuracy.

  3. Hot Extrusion of Aluminum Chips

    NASA Astrophysics Data System (ADS)

    Tekkaya, A. Erman; Güley, Volkan; Haase, Matthias; Jäger, Andreas

    The process of hot extrusion is a promising approach for the direct recycling of aluminum machining chips to aluminum profiles. The presented technology is capable of saving energy, as remelting of aluminum chips can be avoided. Depending on the deformation route and process parameters, the chip-based aluminum extradates showed mechanical properties comparable or superior to cast aluminum billets extruded under the same conditions. Using different metal flow schemes utilizing different extrusion dies the mechanical properties of the profiles extruded from chips can be improved. The energy absorption capacity of the profiles the rectangular hollow profiles extruded from chips and as-cast billets were analyzed using the drop hammer test set-up. The formability of the profiles extruded from chips and as-cast material were compared using tube bending tests in a three-roller-bending machine.

  4. Breakup Densities of Hot Nuclei.

    NASA Astrophysics Data System (ADS)

    Viola, Vic

    2006-04-01

    Breakup densities of hot ^197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E*/A .3ex<˜x 2 MeV, followed by a gradual decrease to a near-constant value of ρ/ρ0˜ 3 for E*/A .3ex>˜x 5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios.

  5. Reactive sintering and reactive hot

    NASA Astrophysics Data System (ADS)

    Murray, J. C.; German, R. M.

    1992-09-01

    NbAl3 has been synthesized from elemental powders by reactive sintering (RS) and reactive hot isostatic pressing (RHIP). Both processes involve a self-propagating exothermic reaction between the constituent powders to form an intermetallic compound. The RHIP approach uses simultaneous external pressurization to make a higher density product. This study focused on developing a method to use reactive synthesis to form high-density NbAl3 compacts. High RS and RHIP densities were possible with the appropriate raw materials and processing parameters. These include powder purity, particle sizes, degassing, heating rate, furnace temperature, and compaction pressures. Near full density was attained with RHIP, and up to 95 pct density was attained with RS.

  6. 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.

  7. 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.

  8. 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

  9. Promising cermets of TiN-Ni for intermediate temperature solid oxide fuel cell interconnects application

    NASA Astrophysics Data System (ADS)

    Gai, Linlin; Liu, Yan; Xin, Xianshuang; Zeng, Zhou; Qi, Qian; Huang, Jian; Liu, Xuejian

    2017-08-01

    Novel TiN-Ni cermets as potential interconnects for intermediate temperature solid oxide fuel cells (IT-SOFCs) are proposed in this study. The cermets with 30, 50 and 70 vol% Ni are fabricated by optimizing the process parameters of the hot-pressed sintering method. With the increase of Ni content in the cermets, the relative density, electrical conductivity, and thermal conductivity are pronounced improved, and the maximum values reach 99.6%, 1.7 × 104 S cm-1 and 45 W m-1 K-1, respectively. In addition, the coefficient of thermal expansion (CTE) of the TiN-Ni cermets in the range of (9.7-13.2) × 10-6 K-1 shows a superior match with other components of IT-SOFCs. Furthermore, the cermets with 70 vol% Ni exhibit excellent oxidation resistance and electrical conductivity retention with a weight gain of only 0.7% and a high conductivity of 1.6 × 104 S cm-1 after oxidizing at 800 °C for 100 h. Our work demonstrates that the TiN-Ni cermets can be used as promising interconnects for the practical application of IT-SOFCs.

  10. Empirical Study of the Multiaxial, Thermomechanical Behavior of NiTiHf Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Shukla, Dhwanil; Noebe, Ronald D.; Stebner Aaron P.

    2013-01-01

    An empirical study was conducted to characterize the multiaxial, thermomechanical responses of new high temperature NiTiHf alloys. The experimentation included loading thin walled tube Ni(sub 50.3)Ti(sub 29.7)Hf(sub 20) alloy samples along both proportional and nonproportional axial-torsion paths at different temperatures while measuring surface strains using stereo digital image correlation. A Ni(sub 50.3)Ti(sub 33.7)Hf(sub 16) alloy was also studied in tension and compression to document the effect of slightly depleting the Hf content on the constitutive responses of NiTiHf alloys. Samples of both alloys were made from nearly texture free polycrystalline material processed by hot extrusion. Analysis of the data shows that very small changes in composition significantly alter NiTiHf alloy properties, as the austenite finish (Af) temperature of the 16-at Hf alloy was found to be approximately 60 C less than the 20-at Hf alloy (approximately 120 C vs. 180 C). In addition, the 16-at Hf alloy exhibited smaller compressive transformation strains (2 vs. 2.5 percent). Multi-axial characterization of the 20-at % Hf alloy showed that while the random polycrystal transformation strains in tension (4 percent) and compression (2.5 percent) are modest in comparison with binary NiTi (6 percent, 4 percent), the torsion performance is superior (7 vs. 4 shear strain width to the pseudoelastic plateau).

  11. Alloying effects on mechanical and metallurgical properties of NiAl

    SciTech Connect

    Liu, C.T.; Horton, J.A.; Lee, E.H.; George, E.P.

    1993-06-01

    Alloying effects were investigated in near-stoichiometric NiAl for improving its mechanical and metallurgical properties. Ternary additions of 19 elements at levels up to 10 at. % were added to NiAl; among them, molybdenum is found to be most effective in improving the room-temperature ductility and high-temperature strength. Alloying with 1.0 {plus_minus} 0.6% molybdenum almost doubles the room-temperature tensile ductility of NiAl and triples its yield strength at 1000C. The creep properties of molybdenum-modified NiAl alloys can be dramatically improved by alloying with up to 1% of niobium or tantalum. Because of the low solubilities of molybdenum and niobium in NiAl, the beneficial effects mainly come from precipitation hardening. Fine and coarse precipitates are revealed by both transmission electron microscopy (TEM) and electron microprobe analyses. Molybdenum-containing alloys possess excellent oxidation resistance and can be fabricated into rod stock by hot extrusion at 900 to 1050C. This study of alloying effects provides a critical input for the alloy design of ductile and strong NiAl aluminide alloys for high-temperature structural applications.

  12. NiTi-Enabled Composite Design for Exceptional Performances

    DOE PAGES

    Shao, Yang; Guo, Fangmin; Ren, Yang; ...

    2017-03-08

    In an effort to further develop shape memory alloys (SMAs) for functional applications, much focus has been given in recent years to design and create innovative forms of SMAs, such as functionally graded SMAs, architecture SMAs, and SMA-based metallic composites. Here, we reports on the progress in creating NiTi-based composites of exceptional properties stimulated by the recent discovery of the principle of lattice strain matching between the SMA matrix and superelastic nanoinclusions embedded in the matrix. And based on this principle, different SMA–metal composites have been designed to achieve extraordinary shape memory performances, such as complete pseudoelastic behavior at asmore » low as 77 K and stress plateau as high as 1600 MPa, and exceptional mechanical properties, such as tensile strength as high as 2000 MPa and Young’s modulus as low as 28 GPa. Details are given for a NiTi–W micro-fiber composite prepared by melt infiltration, hot pressing, forging, and cold rolling. Furthermore, the composite contained 63% in volume of W micro-fibers of ~0.6 μm thickness. In situ synchrotron X-ray diffraction revealed that the NiTi matrix underwent martensite transformation during tensile deformation while the W micro-fiber deformed elastically with a maximum strain of 0.83% in the loading direction, implying a W fiber stress of 3280 MPa. The composite showed a maximum high tensile strength of 2300 MPa.« less

  13. NiTi-Enabled Composite Design for Exceptional Performances

    NASA Astrophysics Data System (ADS)

    Shao, Yang; Guo, Fangmin; Ren, Yang; Zhang, Junsong; Yang, Hong; Jiang, Daqiang; Hao, Shijie; Cui, Lishan

    2017-03-01

    In an effort to further develop shape memory alloys (SMAs) for functional applications, much focus has been given in recent years to design and create innovative forms of SMAs, such as functionally graded SMAs, architecture SMAs, and SMA-based metallic composites. This paper reports on the progress in creating NiTi-based composites of exceptional properties stimulated by the recent discovery of the principle of lattice strain matching between the SMA matrix and superelastic nanoinclusions embedded in the matrix. Based on this principle, different SMA-metal composites have been designed to achieve extraordinary shape memory performances, such as complete pseudoelastic behavior at as low as 77 K and stress plateau as high as 1600 MPa, and exceptional mechanical properties, such as tensile strength as high as 2000 MPa and Young's modulus as low as 28 GPa. Details are given for a NiTi-W micro-fiber composite prepared by melt infiltration, hot pressing, forging, and cold rolling. The composite contained 63% in volume of W micro-fibers of 0.6 μm thickness. In situ synchrotron X-ray diffraction revealed that the NiTi matrix underwent martensite transformation during tensile deformation while the W micro-fiber deformed elastically with a maximum strain of 0.83% in the loading direction, implying a W fiber stress of 3280 MPa. The composite showed a maximum high tensile strength of 2300 MPa.

  14. Synthesis and electrochemical behavior of nanostructured cauliflower-shape Co-Ni/Co-Ni oxides composites

    SciTech Connect

    Gupta, Vinay Kawaguchi, Toshikazu; Miura, Norio

    2009-01-08

    Nanostructured Co-Ni/Co-Ni oxides were electrochemically deposited onto stainless steel electrode by electrochemical method and characterized for their structural and supercapacitive properties. The SEM images indicated that the obtained Co-Ni/Co-Ni oxides had cauliflower-type nanostructure. The X-ray diffraction pattern showed the formation of Co{sub 3}O{sub 4}, NiO, Co and Ni. The EDX elemental mapping images indicated that Ni, Co and O are distributed uniformly. The deposited Co-Ni/Co-Ni oxides showed good supercapacitive characteristics with a specific capacitance of 331 F/g at 1 mA/cm{sup 2} current density in 1 M KOH electrolyte. A mechanism of the formation of cauliflower-shape Co-Ni/Co-Ni oxides was proposed. A variety of promising applications in the fields such as energy storage devices and sensors can be envisioned from Co-Ni/Co-Ni oxides.

  15. Domain Structures and Anisotropy in Exchange-coupled [Co/Pd]-NiFe and [Co/Ni]-NiFe Multilayers

    NASA Astrophysics Data System (ADS)

    Tryputen, Larysa; Chung, Sunjae; Mohseni, Majid; Nguyen, T. N. Anh; Åkerman, Johan; Guo, Feng; McMichael, Robert D.; Ross, Caroline A.

    2014-03-01

    Exchange-coupled multilayers [Co/Pd]5-/NiFe and [Co/Ni]4-NiFe with strong perpendicular magnetic anisotropy have been proposed to use in spin-torque switching and oscillators devices with tilted fixed and free layer to improve their functional performance. We present an experimental study of the magnetization behavior of [Co/Pd]5-/NiFe and [Co/Ni]4-NiFe multilayers measured using magnetometry, magnetic force microscopy (MFM) and ferromagnetic resonance (FMR) as a function of the thickness of the top NiFe layer. We varied the thickness of the NiFe layer in [Co/Pd]5-NiFe (t), t = 0 - 80 nm and [Co/Ni]4-NiFe (t), t = 0.5 - 2.5 nm in order to study the interplay between perpendicular magnetization of the Co/Pd or Co/Ni multilayers and in-plane magnetization of the NiFe. Our magnetometry and FMR data suggest that the [Co/Ni]4/NiFe multilayer behaves like a homogeneous ferromagnetic film with anisotropy that reorients towards in-plane as the NiFe thickness increases, whereas the [Co/Pd]5/NiFe multilayer reveals more complex behavior in which the [Co/Pd] layer retains out-of-plane anisotropy while the magnetization of NiFe layer tilts in-plane with increasing thickness. MFM showed that domains with ~0.1 +/-m size were visible in [Co/Pd]-/NiFe with NiFe thickness of 20-80 nm. Multilayers were patterned into sub-100 nm dots using ion beam etching and their magnetization behavior are compared with unpatterned films.

  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. 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…

  18. 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.

  19. 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…

  20. Demonstrating Integrated Pest Management of Hot Peppers

    USDA-ARS?s Scientific Manuscript database

    We studied the effects of organic and synthetic chemical fertilizers on crop growth, yield and associated insect pests for two varieties of hot pepper, Capsicum chinense Jacquin (Solanaceae): “Scotch Bonnet” and “Caribbean Red” in north Florida. Hot peppers were grown under three treatments: poultr...

  1. DEMONSTRATING INTEGRATED PEST MANAGEMENT OF HOT PEPPERS

    USDA-ARS?s Scientific Manuscript database

    We studied the effects of organic and synthetic chemical fertilizers on crop growth, yield and associated insect pests for two varieties of hot pepper, Capsicum chinense Jacquin (Solanaceae): “Scotch Bonnet” and “Caribbean Red” in north Florida. Hot peppers were grown under three treatments: poultr...

  2. 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…

  3. 29 CFR 1915.14 - Hot work.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Dangerous Atmospheres in Shipyard Employment § 1915.14 Hot work. (a) Hot work requiring testing by a Marine... or on any of the following confined and enclosed spaces and other dangerous atmospheres, boundaries... in or on the following spaces or adjacent spaces or other dangerous atmospheres until they have been...

  4. 29 CFR 1915.14 - Hot work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Dangerous Atmospheres in Shipyard Employment § 1915.14 Hot work. (a) Hot work requiring testing by a Marine... or on any of the following confined and enclosed spaces and other dangerous atmospheres, boundaries... in or on the following spaces or adjacent spaces or other dangerous atmospheres until they have been...

  5. 29 CFR 1915.14 - Hot work.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Dangerous Atmospheres in Shipyard Employment § 1915.14 Hot work. (a) Hot work requiring testing by a Marine... or on any of the following confined and enclosed spaces and other dangerous atmospheres, boundaries... in or on the following spaces or adjacent spaces or other dangerous atmospheres until they have been...

  6. 29 CFR 1915.14 - Hot work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Dangerous Atmospheres in Shipyard Employment § 1915.14 Hot work. (a) Hot work requiring testing by a Marine... or on any of the following confined and enclosed spaces and other dangerous atmospheres, boundaries... in or on the following spaces or adjacent spaces or other dangerous atmospheres until they have been...

  7. 29 CFR 1915.14 - Hot work.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Dangerous Atmospheres in Shipyard Employment § 1915.14 Hot work. (a) Hot work requiring testing by a Marine... or on any of the following confined and enclosed spaces and other dangerous atmospheres, boundaries... in or on the following spaces or adjacent spaces or other dangerous atmospheres until they have been...

  8. 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…

  9. Hot water use at coin laundries

    SciTech Connect

    Lowenstein, A.; Hiller, C.C.

    1999-07-01

    Detailed data on hot water use for one year are presented for two coin laundries. The first is a three-machine laundry that serves half a 50-unit apartment house, and the second is an eight-machine laundry that serves an 82-unit apartment house. For the smaller laundry, the maximum possible demand--i.e., three machines simultaneously filling with hot water--occurred more than once per month. For the larger laundry, the maximum instantaneous demand was equivalent to four machines simultaneously filling with hot water. At this site, the shortest interval in which hot water use equaled that for all eight machines running hot washes was 35 minutes. The data on hot water use for the two laundries were used to validate a methodology for sizing hot water heaters that had been presented at an ASHRAE Symposium. This methodology, which accounts for heating rate, storage capacity, and water temperatures, successfully predicted the conditions when the water heaters would and would not be adequate for the measured loads. The data are an important part of ongoing efforts to characterize the highly diverse universe of hot water use in commercial buildings.

  10. Hot yoga and pregnancy: fitness and hyperthermia.

    PubMed

    Chan, Justin; Natekar, Aniket; Koren, Gideon

    2014-01-01

    One of my pregnant patients wishes to continue her hot yoga exercises during pregnancy. Is this practice safe? With the increased risk of neural tube defects and possibly of other malformations among fetuses exposed to excessive heat, pregnant women should avoid practising hot yoga during pregnancy.

  11. Improved Circuit For Hot-Film Anemometer

    NASA Technical Reports Server (NTRS)

    Gray, David L.

    1993-01-01

    Circuit suitable for automation or computer control of setup and operation. Hot-film or hot-wire anemometer circuit features individual current drives for two arms of wheatstone bridge, plus other features that provide improved calibration and automated or computer-controlled operation.

  12. Hot-wire anemometer for spirography.

    PubMed

    Plakk, P; Liik, P; Kingisepp, P H

    1998-01-01

    The use of a constant temperature hot-wire anemometer flow sensor for spirography is reported. The construction, operating principles and calibration procedure of the apparatus are described, and temperature compensation method is discussed. Frequency response is studied. It is shown that this hot-wire flow transducer satisfies common demands with respect to accuracy, response time and temperature variations.

  13. Hot-Air Ballooning in Physics Teaching.

    ERIC Educational Resources Information Center

    Haugland, Ole Anton

    1991-01-01

    Describes the modern hot-air balloon and the physics of ballooning. Proposes that students construct their own hot-air balloon and presents an experiment calculating the time needed for a balloon to rise to the ceiling of a gymnasium. (MDH)

  14. 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.

  15. 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…

  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. 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)

  18. 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.

  19. 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.

  20. "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 ...

  1. 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…

  2. HotSpot Software Test Plan

    SciTech Connect

    Walker, H; Homann, S G

    2009-03-12

    This Software Test Plan (STP) describes the procedures used to verify and validate that the HotSpot Health Physics Codes meet the requirements of its user base, which includes: (1) Users of the PC version of HotSpot conducting 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. This plan is intended to meet Critical Recommendation 2 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. These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. 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.

  3. 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.…

  4. Classification of hot particles from the Chernobyl accident and nuclear weapons detonations by non-destructive methods.

    PubMed

    Zheltonozhsky, V; Mück, K; Bondarkov, M

    2001-01-01

    Both after the Chernobyl accident and nuclear weapon detonations, agglomerates of radioactive material, so-called hot particles, were released or formed which show a behaviour in the environment quite different from the activity released in gaseous or aerosol form. The differences in their characteristic properties, in the radionuclide composition and the uranium and actinide contents are described in detail for these particles. While nuclear bomb hot particles (both from fission and fusion bombs) incorporate well detectable trace amounts of 60Co and 152Eu, these radionuclides are absent in Chernobyl hot particles. In contrast, Chernobyl hot particles contain 125Sb and 144Ce which are absent in atomic bomb HPs. Obvious differences are also observable between fusion and fission bombs' hot particles (significant differences in 152Eu/l55Eu, 154Eu/155Eu and 238Pu/239Pu ratios) which facilitate the identification of HPs of unknown provensence. The ratio of 239Pu/240Pu in Chernobyl hot particles could be determined by a non-destructive method at 1:1.5. A non-destructive method to determine the content of non-radioactive elements by Kalpha-emission measurements was developed by which inactive Zr, Nb, Fe and Ni could be verified in the particles.

  5. Solvotermal synthesis of NiO, Ni and NiS nanoparticles.

    PubMed

    Gutierrez, Angel; Perpiñán, M Felisa; Sánchez, Ana E; Torralba, M Carmen

    2013-01-01

    Nanoparticles of NiO, Ni or NiS have been obtained by solvothermal decomposition of different molecular precursors. The influence of several parameters, such as temperature, reaction time, solvent or capping agent used, in the nature and size of the obtained nanoparticle has been studied. The characterization by XRD and TEM techniques indicates that the nanoparticles of NiO exhibit average sizes of 3-8 nm, while those of Ni are in the 30-40 nm range. This difference in size has been attributed to the presence of molecules of the capping agent (n-octylamine or oleic acid) that surround the NiO nanoparticles but were not present in the nickel ones. The capping agent is, thus, preventing the aggregation of the smallest nanoparticles. The use of either a S-donor capping agent (4-mercaptopyridine) or a precursor having S-donor ligands (diethyldithiocarbamate) have led to the formation of NiS with average sizes around 35 nm. The magnetic properties of the nanoparticles have been studied, showing superparamagnetism and magnetic hysteresis below the blocking temperature, which, in time, is dependent of the particle size.

  6. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    SciTech Connect

    Swindeman, R.W.

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  7. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    SciTech Connect

    Swindeman, R.W.; Ren, W.

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  8. Magnetoelectric interactions in hot-pressed nickel zinc ferrite and lead zirconante titanate composites

    SciTech Connect

    Srinivasan, G.; DeVreugd, C.P.; Flattery, C.S.; Laletsin, V.M.; Paddubnaya, N.

    2004-09-27

    The synthesis by hot pressing and wide-band (10 Hz-1 MHz) magnetoelectric (ME) characterization of bulk composites of nickel zinc ferrite Ni{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (NZFO) (x=0-0.5) and lead zirconate titanate (PZT) are reported. Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to sintered samples. Frequency dependence of ME coefficients show a three order of magnitude enhancement at electromechanical resonance. The ME coupling is maximum for samples with equal volume of ferrite and PZT. The strongest ME interactions are measured for samples of NZFO (x=0.2) and PZT.

  9. Spatial and temporal variability of sea level rise hot spots over the eastern United States

    NASA Astrophysics Data System (ADS)

    Valle-Levinson, Arnoldo; Dutton, Andrea; Martin, Jonathan B.

    2017-08-01

    Regional sea level rise (SLR) acceleration during the past few decades north of Cape Hatteras has commonly been attributed to weakening Atlantic Meridional Overturning Circulation, although this causal link remains debated. In contrast to this pattern, we demonstrate that SLR decelerated north of Cape Hatteras and accelerated south of the Cape to >20 mm/yr, > 3 times the global mean values from 2011 to 2015. Tide gauge records reveal comparable short-lived, rapid SLR accelerations (hot spots) that have occurred repeatedly over 1500 km stretches of the coastline during the past 95 years, with variable latitudinal position. Our analysis indicates that the cumulative (time-integrated) effects of the North Atlantic Oscillation determine the latitudinal position of these SLR hot spots, while a cumulative El Niño index is associated with their timing. The superposition of these two ocean-atmospheric processes accounts for 87% of the variance in the spatiotemporal pattern of intradecadal sea level oscillations.

  10. Shape coexistence in 68Ni

    NASA Astrophysics Data System (ADS)

    Suchyta, S.; Liddick, S.; Bennet, M.; Larson, N.; Prokop, C.; Quinn, S.; Spyrou, A.; Chemey, A.; Simon, A.; Otsuka, T.; Tsunoda, Y.; Shimizu, N.; Honma, M.; Utsuno, Y.; Tripath, V.; Vonmoss, J.

    2013-10-01

    68 Ni has been a focus of recent work aiming to understand the apparent rapid development of collectivity along neutron-rich N = 40 nuclei, but despite many studies, is not entirely understood. The decay of the first excited 0+ state in 68Ni was investigated at the NSCL. Ions of 68Co were implanted into a planar germanium double-sided strip detector (GeDSSD). The beta decay of 68Co populated the first excited 0+ state in 68Ni and within hundreds of nanoseconds the decay of the first excited 0+ state was measured in the GeDSSD. Both the energy of the first excited 0+ state and the electric monopole transition strength from the first excited 0+ state were precisely determined. Comparisons to Monte Carlo Shell Model calculations suggest shape coexistence between spherical ground and oblate first excited 0+ states in 68Ni. The experimental results and theoretical interpretation will be presented.

  11. 10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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 Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. Link...

  12. 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

    ... 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 Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks....

  13. 10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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 Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks....

  14. Effects of Silicon and Furnace Conditions on Hot Shortness

    NASA Astrophysics Data System (ADS)

    Sampson, Erica E.

    Residual Cu in scrap based steel manufactured in the Electric Arc Furnace (EAF) leads to a surface cracking phenomenon known as surface hot shortness. Si is known to provide a potential reduction in hot shortness; however, the mechanisms involved are not fully understood for low Si quantities. This study aims to determine a window of Si contents with a given Ni content needed to counteract the negative effects of Sn and Cu to reduce hot shortness and to determine the mechanism. Thermogravimetric Analysis, SEM-EDS, XRD, and TEM were used to study the hot shortness behavior of a Fe alloy containing 0.2% Cu, 0.05% Ni, 0.01% Sn and with varying Si-content (0.02%, 0.1%, 0.15%, and 0.2% Si). It was found that fayalite formation at the metal/oxide interface resulted in a reduction of oxidation and subsequent Cu-rich liquid formation for all Si contents examined. Under isothermal air oxidation experiments, the range of Si contents between 0.1-0.2 wt% Si exhibited a mechanism that was a combination of fayalite formation impeding oxidation as well as occlusion of the Cu-rich liquid due to internal oxidation. This range was acceptable to alleviate hot shortness under these conditions. Following continuous casting, steel undergoes a cooling process known as secondary cooling where water is sprayed on the surface to promote cooling followed by a radiant cooling stage where the steel is cooled in air to room temperature. The secondary cooling regime leads to oxidation of the alloy in an air + water vapor atmosphere. Experiments were completed to determine the effect of the non-isothermal secondary cooling cycle, the effect of water vapor during secondary cooling, and the effect of the radiant cooling regime down to room temperature. In the case of secondary cooling atmospheres, the non-isothermal cooling cycle resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles due to the higher temperatures experienced in

  15. Microstructure changes in high-speed hot rolling of steel rods

    NASA Astrophysics Data System (ADS)

    Klimanek, P.; Hensger, K.-E.; Schubert, A.; Barthel, M.

    1988-04-01

    Transmission electron microscopy (TEM), quantitative texture analysis by means of neutron diffraction (QTA) and X-ray diffraction profile analysis (XDPA) were used to study the microstructure changes occurring in high-speed hot rolling (dot \\varphi ≦1500 s-1; T=1073 K) of high-alloy stainless steel X8CrTi17 (ferrite) and X8CrNiTi18.10 (austenite). The investigations indicate that at higher deformation rates recrystallization due to adiabatic overheating becomes an important process of microstructure formation.

  16. RECENT PROGRESS IN THE DEVELOPMENT OF DUCTILE-PHASE TOUGHENED TUNGSTEN FOR PLASMA-FACING MATERIALS: W-Ni-Fe COMPOSITES

    SciTech Connect

    Henager, Charles H.; Kurtz, Richard J.; Roosendaal, Timothy J.; Borlaug, Brennan A.; Nyberg, Eric A.; Lavender, Curt A.; Odette, G Robert; Cunningham, Kevin; Zok, Frank W.

    2015-03-02

    A promising approach to increasing fracture toughness and decreasing the DBTT of a W-alloy is by ductile-phase toughening (DPT) [1-3]. In this method, a ductile phase is included in a brittle matrix to prevent fracture propagation by crack bridging. W-Ni-Fe alloys consisting of nearly spherical W-particles embedded within a Fe-Ni-W ductile matrix are being manipulated by hot-rolling to create lamellar W/Fe-Ni-W composites with anisotropic fracture properties.

  17. Obliquity Tides in Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Peale, S. J.

    two papers have pointed out that this is not so (Levrard et al. 2007; Fabrycky et al. 2007). The rotation continues to decrease below the synchronous value with increasing obliquity. As is perhaps expected, state 2 becomes unstable as the planet slows. The planet then rapidly evolves to Cassini state 1 with a negligibly small obliquity, and all isolated hot Jupiters will evolve to nearly circular orbits with their spin axes nearly normal to their orbit planes. Obliquity tides cannot be invoked as a means of additional heating of hot gaseous planets.

  18. Cancer treatment: dealing with hot flashes and night sweats

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000826.htm Cancer treatment: dealing with hot flashes and night sweats To ... this page, please enable JavaScript. Certain types of cancer treatments can cause hot flashes and night sweats. Hot ...

  19. Measurement of 59Ni and 63Ni by accelerator mass spectrometry at CIAE

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoming; He, Ming; Ruan, Xiangdong; Xu, Yongning; Shen, Hongtao; Du, Liang; Xiao, Caijin; Dong, Kejun; Jiang, Shan; Yang, Xuran; Lan, Xiaoxi; Wu, Shaoyong; Zhao, Qingzhang; Cai, Li; Pang, Fangfang

    2015-10-01

    The long lived isotopes 59Ni and 63Ni can be used in many areas such as radioactive waste management, neutron dosimetry, cosmic radiation study, and so on. Based on the large accelerator and a big Q3D magnetic spectrometer, the measurement method for 59Ni and 63Ni is under development at the AMS facility at China Institute of Atomic Energy (CIAE). By using the ΔE-Q3D technique with the Q3D magnetic spectrometer, the isobaric interferences were greatly reduced in the measurements of 59Ni and 63Ni. A four anode gas ionization chamber was then used to further identify isobars. With these techniques, the abundance sensitivities of 59Ni and 63Ni measurements are determined as 59Ni/Ni = 1 × 10-13 and 63Ni/Ni = 2 × 10-12, respectively.

  20. Accessing Ni(III)-thiolate versus Ni(II)-thiyl bonding in a family of Ni-N2S2 synthetic models of NiSOD.

    PubMed

    Broering, Ellen P; Dillon, Stephanie; Gale, Eric M; Steiner, Ramsey A; Telser, Joshua; Brunold, Thomas C; Harrop, Todd C

    2015-04-20

    Superoxide dismutase (SOD) catalyzes the disproportionation of superoxide (O2(• -)) into H2O2 and O2(g) by toggling through different oxidation states of a first-row transition metal ion at its active site. Ni-containing SODs (NiSODs) are a distinct class of this family of metalloenzymes due to the unusual coordination sphere that is comprised of mixed N/S-ligands from peptide-N and cysteine-S donor atoms. A central goal of our research is to understand the factors that govern reactive oxygen species (ROS) stability of the Ni-S(Cys) bond in NiSOD utilizing a synthetic model approach. In light of the reactivity of metal-coordinated thiolates to ROS, several hypotheses have been proffered and include the coordination of His1-Nδ to the Ni(II) and Ni(III) forms of NiSOD, as well as hydrogen bonding or full protonation of a coordinated S(Cys). In this work, we present NiSOD analogues of the general formula [Ni(N2S)(SR')](-), providing a variable location (SR' = aryl thiolate) in the N2S2 basal plane coordination sphere where we have introduced o-amino and/or electron-withdrawing groups to intercept an oxidized Ni species. The synthesis, structure, and properties of the NiSOD model complexes (Et4N)[Ni(nmp)(SPh-o-NH2)] (2), (Et4N)[Ni(nmp)(SPh-o-NH2-p-CF3)] (3), (Et4N)[Ni(nmp)(SPh-p-NH2)] (4), and (Et4N)[Ni(nmp)(SPh-p-CF3)] (5) (nmp(2-) = dianion of N-(2-mercaptoethyl)picolinamide) are reported. NiSOD model complexes with amino groups positioned ortho to the aryl-S in SR' (2 and 3) afford oxidized species (2(ox) and 3(ox)) that are best described as a resonance hybrid between Ni(III)-SR and Ni(II)-(•)SR based on ultraviolet-visible (UV-vis), magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) spectroscopies, as well as density functional theory (DFT) calculations. The results presented here, demonstrating the high percentage of S(3p) character in the highest occupied molecular orbital (HOMO) of the four-coordinate reduced form of NiSOD (Ni

  1. 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).

  2. Hot Gas in Planetary Nebulae

    NASA Technical Reports Server (NTRS)

    Gruendl, Robert A.; Chu, You-Hua; Guerrero, Martin

    2003-01-01

    It was successfully obtained the FUSE spectra of all targets awarded. The analysis of the spectra has been a complex task due to the superposition of the P-Cygni profile from the wind of the central star and absorption components from low ionization and molecular species in the nebular shell. In six of the eight targets there are narrow O VI absorption components that may arise from the interface layer between the hot (l0(exp 6) K) interior gas and the surrounding warm (l0(exp 4) K) dense nebular shell. To better determine whether these narrow O VI absorption lines arise from the interface region we have obtained ground-based high-dispersion spectroscopic observations of the central star and nebula to pin-point the precise line-of-sight velocity of the nebular emission lines. The comparison between these optical spectra with the far-UV spectra obtained with FUSE is complete. The analysis shows that in most cases the narrow O VI absorption components have velocities slightly redshifted from the emission lines which arise from the approaching side of the nebular shell. Preliminary results have been published in two papers.

  3. Hot Gas in Planetary Nebulae

    NASA Technical Reports Server (NTRS)

    Gruendl, Robert A.; Chu, You-Hua; Guerrero, Martin

    2003-01-01

    It was successfully obtained the FUSE spectra of all targets awarded. The analysis of the spectra has been a complex task due to the superposition of the P-Cygni profile from the wind of the central star and absorption components from low ionization and molecular species in the nebular shell. In six of the eight targets there are narrow O VI absorption components that may arise from the interface layer between the hot (l0(exp 6) K) interior gas and the surrounding warm (l0(exp 4) K) dense nebular shell. To better determine whether these narrow O VI absorption lines arise from the interface region we have obtained ground-based high-dispersion spectroscopic observations of the central star and nebula to pin-point the precise line-of-sight velocity of the nebular emission lines. The comparison between these optical spectra with the far-UV spectra obtained with FUSE is complete. The analysis shows that in most cases the narrow O VI absorption components have velocities slightly redshifted from the emission lines which arise from the approaching side of the nebular shell. Preliminary results have been published in two papers.

  4. Iron Aluminide Hot Gas Filters

    SciTech Connect

    Hurley, J.; Brosious, S.; Johnson, M.

    1996-12-31

    Currently, high temperature filter systems are in the demonstration phase with the first commercial scale hot filter systems being installed on integrated gasification combined cycle (IGCC) and pressurized fluid bed combustion cycle (PBFC) systems (70 MW). They are dependent on the development of durable and economic high temperature filter systems. These filters are mostly ceramic tubes or candles. Ceramic filter durability has not been high. Failure is usually attributed to mechanical or thermal shock: they can also undergo significant changes due to service conditions. The overall objective of this project is to commercialize weldable, crack resistant filters which will provide several years service in advanced power processes. The specific objectives of this project are to develop corrosion resistant alloys and manufacturing processes to make Iron Aluminide filter media, and to use a ``short term`` exposure apparatus supported by other tests to identify the most promising candidate (alloy plus sintering cycle). The objectives of the next phases are to demonstrate long term corrosion stability for the best candidate followed by the production of fifty filters (optional).

  5. Hot Tub Folliculitis: A Clinical Syndrome

    PubMed Central

    Zacherle, Barry J.; Silver, Diane S.

    1982-01-01

    With the increasing use of hot tubs, patients are being seen with a distinct clinical syndrome that appears several hours or days after hot tub exposure. It consists of a maculovesicular, often pruritic rash, and commonly occurring associated symptoms including fever, upper respiratory tract complaints, axillary adenopathy and breast tenderness. Cultures in the cases described here grew out Pseudomonas aeruginosa, giving a diagnosis of Pseudomonas folliculitis. The illness clears spontaneously without any treatment. Proper attention to hot tub chlorination and use are probably important in preventing this problem, and awareness of the syndrome by physicians may prevent unnecessary and costly diagnostic studies and treatment programs. PMID:7147933

  6. Polyakov loop modeling for hot QCD

    NASA Astrophysics Data System (ADS)

    Fukushima, Kenji; Skokov, Vladimir

    2017-09-01

    We review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.

  7. Hot Carriers in Semiconductors 6, Scottsdale, Arizona

    DTIC Science & Technology

    1989-11-01

    Hamburg MP-2 "Tunable cyclotron-resonance laser based on hot holes in germanium applied to FIR-spectroscopy of GaAs heterostructures," K. Unterrainer...34Frequency range and distributions of inverted hot hole generated FIR in germanium ," V. I. Gavrilenko, N. G. Kalugin, Z F. Krasirnik, and V. V. Nikonorov, Q...semiconductor superlattices," P. England, J. R. Hayes, E. Colas, and M. Helm, Red Bank 2:50 p.m. MC-2 "High-field transport and NDR with hot phonons in

  8. Do hot baths promote anal sphincter relaxation?

    PubMed

    Pinho, M; Correa, J C; Furtado, A; Ramos, J R

    1993-03-01

    Hot perineal baths have been prescribed for the treatment of painful anorectal conditions such as anal fissures and perianal hematomas or for the postoperative care of hemorrhoidectomy. Despite this widely accepted benefit, no studies have been performed to determine whether there is a rational explanation for this procedure. Anorectal manometry was performed in 40 control subjects with no anorectal complaints before and after a hot perineal bath. No significant difference was found between anal pressures at rest or during voluntary contraction before and after the bath. We conclude from this study that no relaxation of anal sphincters can be obtained by hot perineal baths in normal subjects.

  9. Is the moon hot or cold.

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.; Hanks, T. C.

    1972-01-01

    Basic observations are discussed which do not demand a presently cold moon and are consistent with a hot moon. It is suggested that an iron-deficient, highly resistive, hot lunar interior, capped by a cool, rigid lunar lithosphere with a thickness of several hundred kilometers, can explain the relevant observations and is a reasonable model of the moon today. The strength of the moon, lunar electrical conductivity profiles, the relative absence of present-day volcanic activity, and thermal history considerations are examined. Whether the deep interior of the moon is hot or cold has an important bearing on the overall composition of the moon and its origin.

  10. Elevated temperature slow plastic deformation of NiAl-TiB2 particulate composites at 1200 and 1300 K

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Viswanadham, R. K.; Mannan, S. K.; Sprissler, B.

    1990-01-01

    Elevated temperature compression testing has been conducted in air at 1200 and 1300 K with strain rates varying from about 10 to the -4th to about 10 to the -7th/sec on NiAl-TiB2 particulate composites. These materials, which consisted of a B2 crystal structure intermetallic Ni-50 at. pct Al matrix and from 0 to 30 vol pct of approximately 1- micron diameter TiB2 particles, were fabricated by XD synthesis and hot pressed to full density. Flow strength of the composites increased with volume fraction of the strengthening phase with NiAl-30TiB2 being approximately three times stronger than NiAl. Comparison of the light optical and TEM microstructures of as-received and tested samples revealed that reactions did not occur between the two phases, and NiAl-TiB2 interfaces were not cracked during deformation. Additional TEM indicated that the particles stabilize a vastly different microstructure in the NiAl matrix of the composites than that formed in unreinforced NiAl.

  11. Interface stability in the Ni-Cr-AI system: Part I. morphological stability of β-γ diffusion couple interfaces at 1150°C

    NASA Astrophysics Data System (ADS)

    Merchant, Sailesh M.; Notis, Michael R.; Goldstein, Joseph I.

    1990-07-01

    Aluminide coatings on Ni-base superalloys offer resistance to oxidation and hot corrosion at elevated temperatures. Complex depositional and subsequent diffusional interactions of the coating with the substrate result in a multiphase product consisting primarily of β-NiAl and γ'-Ni3Al intermediate phases. An understanding of interfacial stability between the coating and the substrate is therefore necessary in order to explain the formation of such phases. The Ni-Cr-AI system serves to simplify the complex chemistry of most Ni-base superalloys. In this study, reaction diffusion and interfacial stability were investigated in solid-solid diffusion couples, consisting of a common β-Ni50Al end-member and a series of γ-pure Ni, binary Ni-Cr, and ternary Ni-Cr-Al alloys, isothermally annealed at 1150 °C for 49 hours. The morphological development of the interface was examined using optical metallography and quantitative information obtained using electron-probe microanalysis. A transition from a stable or planar to an unstable or nonplanar interface in the β-γ diffusion couples was observed with the systematic variation in Cr content of the γ end-member. Interface breakdown in the β-γ couples was explained by means of microstructural information gathered about interfaces, measured diffusion paths, and a knowledge of phase constitution relationships.

  12. Differential bleaching of corals based on El Niño type and intensity in the Andaman Sea, southeast Bay of Bengal.

    PubMed

    Lix, J K; Venkatesan, R; Grinson, George; Rao, R R; Jineesh, V K; Arul, Muthiah M; Vengatesan, G; Ramasundaram, S; Sundar, R; Atmanand, M A

    2016-03-01

    The Andaman coral reef region experienced mass bleaching events during 1998 and 2010. The purpose of this study is to investigate the role of the El Niño in the coral reef bleaching events of the Andaman region. Both Niño 3.4 and 3 indices were examined to find out the relationship between the mass bleaching events and El Niño, and correlated with sea surface temperature (SST) anomalies in the Andaman Sea. The result shows that abnormal warming and mass bleaching events in the Andaman Sea were seen only during strong El Niño years of 1997-1998 and 2009-2010. The Andaman Sea SST was more elevated and associated with El Niño Modoki (central Pacific El Niño) than conventional El Niño (eastern Pacific El Niño) occurrences. It is suggested that the development of hot spot patterns around the Andaman Islands during May 1998 and April-May 2010 may be attributed to zonal shifts in the Walker circulation driven by El Niño during the corresponding period.

  13. Hot Flashes amd Night Sweats (PDQ)

    MedlinePlus

    ... fever and may occur without disease in warm climates, during exercise, and during hot flashes in menopause . ... The PDQ summaries are based on an independent review of the medical literature. They are not policy ...

  14. 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.

  15. 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.

  16. 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.

  17. The possible hot nature of cold fusion

    SciTech Connect

    Kuehne, R.W. )

    1994-03-01

    Based on the model of micro hot fusion, the neutron emission rate of cold fusion is determined without the need for fine-tuning parameters. Moreover, the experimental conditions that are essential to reproduce fusion are determined. 84 refs.

  18. Frequency Responses Of Hot-Wire Anemometers

    NASA Technical Reports Server (NTRS)

    Watmuff, Jonathan H.

    1992-01-01

    Report describes theoretical study of frequency response of constant-temperature hot-wire anemometer, with view toward increasing frequency response while maintaining stable operation in supersonic flow. Effects of various circuit parameters discussed.

  19. Coulomb explosion of “hot spot”

    SciTech Connect

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

    2016-09-15

    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.

  20. A New Hot Spot on Northern Io

    NASA Image and Video Library

    2001-12-10

    In August 2001, NASA Galileo spacecraft has returned imagery of a hot spot on Jupiter moon Io that was the source of a towering plume indicating a sulfur-dioxide concentration that may have been fallout from the plume.

  1. Hot wire anemometry in transonic flow

    NASA Technical Reports Server (NTRS)

    Horstman, C. C.; Rose, W. C.

    1975-01-01

    The use of hot-wire anemometry for obtaining fluctuating data in transonic flows has been evaluated. From hot-wire heat loss correlations based on previous transonic data, the sensitivity coefficients for velocity, density, and total temperature fluctuations have been calculated for a wide range of test conditions and sensor parameters. For sensor Reynolds numbers greater than 20 and high sensor overheat ratios, the velocity sensitivity remains independent of Mach number and equal to the density sensitivity. These conclusions were verified by comparisons of predicted sensitivities with those from recent direct calibrations in transonic flows. Based on these results, techniques are presented to obtain meaningful measurements of fluctuating velocity, density, and Reynolds shear stress using hot-wire and hot-film anemometers. Examples of these measurements are presented for two transonic boundary layers.

  2. Hot-wire anemometry in transonic flow

    NASA Technical Reports Server (NTRS)

    Horstman, C. C.; Rose, W. C.

    1977-01-01

    The use of hot-wire anemometry for obtaining fluctuating data in transonic flows has been evaluated. From hot-wire heat loss correlations based on previous transonic data, the sensitivity coefficients for velocity, density, and total temperature fluctuations have been calculated for a wide range of test conditions and sensor parameters. For sensor Reynolds number greater than 20 and high sensor overheat ratios, the velocity sensitivity remains independent of Mach number and equal to the density sensitivity. These conditions were verified by comparisons of predicted sensitivities with those from recent direct calibrations in transonic flows. Based on these results, techniques are presented to obtain meaningful measurements of fluctuating velocity, density, and Reynolds shear stress using hot-wire and hot-film anemometers. Example of these measurements are presented for two transonic boundary layers.

  3. Bouncing Balls and Hot Rod Races.

    ERIC Educational Resources Information Center

    Tibbs, Peggy; Sherrill, Donna

    This paper presents the Bouncing Ball Experiment which models quadratic and exponential functions, and the Hot Rod Races activity that explores velocity and acceleration. Activities include directions for the use of TI-82 and TI-83 calculators. (YDS)

  4. 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.

  5. Superalloys resist hot corrosion and oxidation

    SciTech Connect

    Erickson, G.L.

    1997-03-01

    Demand for lower fuel costs is driving turbine designers on all fronts to look for ways to increase firing temperatures to achieve higher operating efficiencies. Historically, hot corrosion attack has been the dominant environmental issue for industrial gas turbine engines. Now, efforts to raise firing temperatures create the need for materials that can endure exposures where both hot corrosion and oxidation predominate. Two single-crystal superalloys have been developed in response to these market demands. By providing a blend of hot corrosion and oxidation resistance, CMSX-11B and CMSX-11C alloys directly address the need for better components in turbine engines that burn fossil fuels. This article discusses alloy design and manufacture, mechanical properties, and results of hot corrosion and oxidation tests.

  6. Static atomic displacements in Ni-rich Ni-Al

    NASA Astrophysics Data System (ADS)

    Schönfeld, B.; Kostorz, G.; Celino, M.; Rosato, V.

    2001-05-01

    Short-range order and static atomic displacement parameters, previously determined from diffuse neutron scattering for Ni-8.9 at.% Al equilibrated at 775 K and quenched to room temperature, were used to study lattice relaxation effects in molecular-dynamics simulations. An occupation of average lattice sites with Ni and Al atoms compatible with the short-range ordered state was taken as the starting situation. Displacement parameters obtained from the relaxation simulations and from diffuse neutron scattering show general similarity in magnitude and dependence on distance. Also, the species dependence of the displacement parameters known from diffuse X-ray scattering investigations is reproduced in magnitude.

  7. Synthesis and Characterization of Pure Ni and Ni-Sn Intermetallic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Yakymovych, A.; Ipser, H.

    2017-02-01

    The present research focused on the synthesis of Ni and Ni-Sn nanoparticles via a chemical reduction method using hydrazine hydrate. The syntheses were performed applying highly purified water or diethylene glycol as solvent. The produced nanoparticles were characterized by scanning electron microscopy and powder X-ray diffraction. The as-synthesized Ni-Sn nanoparticles with nominal starting ratios Ni:Sn = 3:1, 3:2, and 3:4 consisted of different amounts of pure Ni and a low-temperature Ni3Sn2 phase. It was found that all synthesized nanopowders had a spherical shape with the largest average size for pure Ni and decreasing size for particles containing Sn. X-ray diffraction showed that all synthesized nanoparticles contained Ni and a low-temperature Ni3Sn2 phase independent of the initial molar ratio; while Ni3Sn and Ni3Sn4 could not be detected.

  8. Effect of boron on intergranular hot cracking in Ni-Cr-Fe superalloys containing niobium

    NASA Technical Reports Server (NTRS)

    Thompson, R. G.

    1990-01-01

    Solidification mechanisms had a dominant influence on microfissuring behavior of the test group. Carbon modified the Laves formation significantly and showed that one approach to alloy design would be balancing carbide formers against Laves formers. Boron's strong effect on microfissuring can be traced to its potency as a Laves former. Boron's segregation to grain boundaries plays at best a secondary role in microfissuring.

  9. Feasibility of Hot-Block Anemometry.

    DTIC Science & Technology

    1988-02-29

    operate constant- temperature hot-wires and hot- films (Refs. 30-33) and temperature sensors (Ref. 34) was applied to the Phase I prototype probes...by simpler and less expensive electronics: simple thermistor circuits could be used for the * temperature sensors and only one anemometer amplifier and...thermal losses due to forced convection from a small body, a sphere or block. Temperature or heat-transfer sensors are located to measure variations in

  10. Turbine Engine Hot Section Technology (HOST) Project

    NASA Technical Reports Server (NTRS)

    Sokolowski, Daniel E.; Ensign, C. Robert

    1986-01-01

    The Hot Section Technology (HOST) Project is a NASA-sponsored endeavor to improve the durability of advanced gas turbine engines for commercial and military aircraft. Through improvements in the analytical models and life prediction systems, designs for future hot section components, the combustor and turbine, will be more accurately analyzed and will incorporate features required for longer life in the more hostile operating environment of high performance engines.

  11. Hot Wall Thickness Variation Measurement System

    DTIC Science & Technology

    1979-06-01

    Subtltia) HOT WALL THICKNESS VARIATION MEASUREMENT SYSTEM 7. AUTHORfa; 3. J. KRUPSKI 9 . PERFORMING ORGANIZATION NAME AND ADDRESS PRODUCT...THE FORGING 3. ULTRASONICS ON A HOT TUBE 4. SYSTEt-l DESCRIPTION 5. TESTING RESULTS 6. CONCLUSIONS 7. HffLEMENTATION PAGE i ii 1 2 4 6 9 ...printed out. The grip procedure was repeated toward the breech end of the forging with good results. The third and 9 breech end prints were at about

  12. 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.

  13. Sampling Particles In Hot Gas Plumes

    NASA Technical Reports Server (NTRS)

    Taylor, James F.; Sambamurthi, Jay

    1994-01-01

    Sampling darts and launching apparatus built to collect particles in vertical plume of hot gas. In original application, hot gas plume is rocket-engine exhaust during test firing. Dart passes made at various heights, depending on launch angle and launch-gas pressure. Adaptable to variety of terrestrial uses like research on particulate emissions of volcanoes or determining origin of building fire while still burning.

  14. The menopausal hot flush: a review.

    PubMed

    Sturdee, D W; Hunter, M S; Maki, P M; Gupta, P; Sassarini, J; Stevenson, J C; Lumsden, M A

    2017-04-05

    The hot flush is the most characteristic and often the most distressing symptom of the menopause. It is a unique feature and yet the mechanism and health implications are still not fully understood. This review summarizes some of the current thoughts on factors contributing to flushing, the physiological, vascular and neuroendocrine changes associated with flushing and the possible cardiovascular and other health implications for women experiencing hot flushes. Therapy is not discussed.

  15. Preparation and property of duplex Ni-B-TiO2/Ni nano-composite coatings

    NASA Astrophysics Data System (ADS)

    Wang, Shu-Jen; Wang, Yuxin; Shu, Xin; Tay, Seeleng; Gao, Wei; Shakoor, R. A.; Kahraman, Ramazan

    2015-03-01

    The duplex Nickel-Boron-Titania/Nickel (Ni-B-TiO2/Ni) coatings were deposited on mild steel by using two baths with Ni as the inner layer. TiO2 nanoparticles were incorporated into the Ni-B coatings as the outer layer by using solid particle mixing method. The microstructure, morphology and corrosion resistance of the duplex Ni-B-TiO2/Ni nanocomposite coatings were systemically investigated. The results show that the duplex interface was uniform and the adhesion between two layers was very good. The microhardness of duplex Ni-B-TiO2/Ni coating was much higher than the Ni coating due to the outer layer of Ni-B-TiO2 coating. The corrosion resistance of the duplex Ni-B-TiO2/Ni coating was also significantly improved comparing with single Ni-B coating. The Ni-B-10 g/L TiO2/Ni coating was found to have the best corrosion resistance among these duplex coatings. This type of duplex Ni-B-TiO2/Ni coating, with high hardness and good corrosion resistance properties, should be able to find broad applications under adverse environmental conditions.

  16. Effect of applied stress, crystal orientation, and phases on type-II hot corrosion of CMSX-4

    NASA Astrophysics Data System (ADS)

    Lortrakul, Pongpat

    Gas turbine blades encounter corrosion problems, especially at the bare metal connection between the blades and the rotor. Elevated temperatures, a corrosive environment, and high stress are factors that can reduce blade lifespan. Thus, understanding the relation between corrosion behavior and stress is key to improving the design of turbine blades and their operation. Type-II hot corrosion mechanisms (700 °C in flowing 1000 ppm-SO2 with Na2SO4 on the specimen surface) are representative of this problem, and Meier and Luthra have expertly established the mechanisms of Ni-alloy and Co-alloy systems. However, little research has focused on CMSX-4, which is a Ni-based superalloy single crystal. Moreover, research on the effects of phases (eutectic and gamma' size), crystal orientations, and applied stress is lacking. In this research, tests of the early stages of hot corrosion---from 3 minutes to 50 hours of exposure---are performed to develop an understanding of type-II hot corrosion mechanism in CMSX-4.The discovery is that a single Cobalt oxide rich layer is initially formed above NiO in the outward oxidation and turns into spheroids afterward. A unique remnant gamma' precipitate structure is observed in the inward oxidation zone and this evidence indicates the preferential corrosion behavior. Sulfur layer above the original surface is one of the causes influencing the overall oxidation thickness by pushing the outward oxidation scale. As-cast CMSX-4 with a wide variety of phases is used to examine the phase effects. With short exposure, coarse gamma' phase influences the inward oxidation thickness but the effect becomes less with time. Specimens with different orientations (growth and transverse directions) are used to examine orientation effect. A notched specimen with a wedge was invented to maintain a stress gradient during hot corrosion test. The results suggest that there may be an effect of stress on the overall oxidation thickness.

  17. Modeling deflagration waves out of hot spots

    NASA Astrophysics Data System (ADS)

    Partom, Yehuda

    2017-01-01

    It is widely accepted that shock initiation and detonation of heterogeneous explosives comes about by a two-step process known as ignition and growth. In the first step a shock sweeping through an explosive cell (control volume) creates hot spots that become ignition sites. In the second step, deflagration waves (or burn waves) propagate out of those hot spots and transform the reactant in the cell into reaction products. The macroscopic (or average) reaction rate of the reactant in the cell depends on the speed of those deflagration waves and on the average distance between neighboring hot spots. Here we simulate the propagation of deflagration waves out of hot spots on the mesoscale in axial symmetry using a 2D hydrocode, to which we add heat conduction and bulk reaction. The propagation speed of the deflagration waves may depend on both pressure and temperature. It depends on pressure for quasistatic loading near ambient temperature, and on temperature at high temperatures resulting from shock loading. From the simulation we obtain deflagration fronts emanating out of the hot spots. For 8 to 13 GPa shocks, the emanating fronts propagate as deflagration waves to consume the explosive between hot spots. For higher shock levels deflagration waves may interact with the sweeping shock to become detonation waves on the mesoscale. From the simulation results we extract average deflagration wave speeds.

  18. 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.

  19. Canopy hot-spot as crop identifier

    SciTech Connect

    Gerstl, S.A.W.; Simmer, C.; Powers, B.J.

    1986-05-01

    Illuminating any reflective rough or structured surface by a directional light source results in an angular reflectance distribution that shows a narrow peak in the direction of retro-reflection. This is called the Heiligenschein or hot-spot of vegetation canopies and is caused by mutual shading of leaves. The angular intensity distribution of the hot-spot, its brightness and slope, are therefore indicators of the plant's geometry. We propose the use of hot-spot characteristics as crop identifiers in satellite remote sensing because the canopy hot-spot carries information about plant stand architecture that is more distinctive for different plant species than, for instance, their spectral reflectance characteristics. A simple three-dimensional Monte Carlo/ray tracing model and an analytic two-dimensional model are developed to estimate the angular distribution of the hot-spot as a function of the size of the plant leaves. The results show that the brightness-distribution and slope of the hot-spot change distinctively for different leaf sizes indicating a much more peaked maximum for the smaller leaves.

  20. Rocket engine hot-spot detector

    NASA Astrophysics Data System (ADS)

    Collamore, F. N.

    1985-04-01

    On high performance devices such as rocket engines it is desirable to know if local hot spots or areas of reduced cooling margin exist. The objective of this program is to design, fabricate and test an electronic hot spot detector capable of sensing local hot spot on the exterior circumference of a regeneratively cooled combustion chamber in order to avoid hardware damage. The electronic hot spot sensor consists of an array of 120 thermocouple elements which are bonded in a flexible belt of polyimide film. The design temperature range is from +30 F to +400 F continuously with an intermittent temperature of 500 F maximum. The thermocouple belt consists of 120 equally spaced copper-Constantan thermocouple junctions which is wrapped around the OMS liquid rocket engine combustion chamber, to monitor temperatures of individual cooling channels. Each thermocouple is located over a cooling channel near the injector end of the combustion chamber. The thermocouple array sensor is held in place by a spring loaded clamp band. Analyses show that in the event of a blocked cooling channel the surface temperature of the chamber over the blocked channel will rise from a normal operating temperature of approx. 300 F to approx. 600 F. The hot spot detector will respond quickly to this change with a response time constant less than 0.05 seconds. The hot spot sensor assembly is fabricated with a laminated construction of layers of Kapton film and an outer protective layer of fiberglass reinforced silicone rubber.

  1. Hot Jupiter Radii: A Turbulent History

    NASA Astrophysics Data System (ADS)

    Youdin, Andrew N.; Komacek, Thaddeus D.

    2014-11-01

    Many hot Jupiters, i.e. giant exoplanets with short orbital periods, are bloated, with radii that greatly exceed those of colder gas giants. In models that neglect atmospheric motion, the enhanced irradiation of hot Jupiters is insufficient to explain their large radii. However uneven surface irradiation drives atmospheric circulation. These atmospheric motions deposit heat at deeper layers than irradiation alone, and can explain their large radii. The specific dissipation mechanism for atmospheric circulation can involve a turbulent cascade and/or the driving of electric currents that undergo Ohmic dissipation. The “Mechanical Greenhouse” model (Youdin & Mitchell, 2010) showed that turbulence in hot Jupiter atmospheres does mechanical work against the stable stratification of upper radiative zones, thereby driving a heat flux deeper into the interior. This poster will describe the first efforts to include this turbulent heat flux in planetary structure models. The goal is to understand the effects of turbulent mixing on hot Jupiter radius evolution. To perform these calculations we modify the publicly available stellar structure code MESA. We show how the effects of turbulence can be included in MESA — and understood physically — as an effective dissipation profile. We compare the radius evolution of hot Jupiters for different dissipation prescriptions, including our turbulent mixing model and others from the literature. We find that turbulent mixing is an energetically efficient way to explain the bloated radii of hot Jupiters.

  2. 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.

  3. 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.

  4. Shape coexistence in Ni68

    NASA Astrophysics Data System (ADS)

    Suchyta, S.; Liddick, S. N.; Tsunoda, Y.; Otsuka, T.; Bennett, M. B.; Chemey, A.; Honma, M.; Larson, N.; Prokop, C. J.; Quinn, S. J.; Shimizu, N.; Simon, A.; Spyrou, A.; Tripathi, V.; Utsuno, Y.; VonMoss, J. M.

    2014-02-01

    The internal-conversion and internal-pair-production decays of the first excited 0+ state in Ni68 are studied following the β decay of Co68. A novel experimental technique, in which the ions of Co68 were implanted into a planar germanium double-sided strip detector and which required digital pulse processing, is developed. The values for the energy of the first excited 0+ state and the electric monopole transition strength from the first excited 0+ state to the ground state in Ni68 are determined to be 1605(3) keV and 7.6(4)×10-3, respectively. Comparisons of the experimental results to Monte Carlo shell-model calculations suggest the coexistence between a spherical ground state and an oblate first excited 0+ state in Ni68.

  5. Thermal modeling of NiH2 batteries

    NASA Technical Reports Server (NTRS)

    Ponthus, Agnes-Marie; Alexandre, Alain

    1994-01-01

    The following are discussed: NiH2 battery mission and environment; NiH2 cell heat dissipation; Nodal software; model development general philosophy; NiH2 battery model development; and NiH2 experimental developments.

  6. The Solubility of Rock in Steam Atmospheres of the Early Earth and Hot Rocky Exoplanets

    NASA Astrophysics Data System (ADS)

    Fegley, Bruce

    2016-07-01

    Extensive experimental studies show all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky element - bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show Earth's sub-solar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure. This work was supported by NSF Astronomy Program Grant AST-1412175.

  7. Microstructural control in hot working of IN-718 superalloy using processing map

    SciTech Connect

    Srinivasan, N.; Prasad, Y.V.R.K. . Dept. of Metallurgy)

    1994-10-01

    the hot-working characteristics of IN-718 are studied in the temperature range 900 C to 1,200 C and strain rate range 0.001 to 100 s[sup [minus]1] using hot compression tests. Processing maps for hot working are developed on the basis of the strain-rate sensitivity variations with temperature and strain rate and interpreted using a dynamic materials model. The map exhibits two domains of dynamic recrystallization (DRX): one occurring at 950 C and 0.001 s[sup [minus]1] with an efficiency of power dissipation of 37 pct and the other at 1200 C and 0.1 s[sup [minus]1] with an efficiency of 40 pct. Dynamic recrystallization in the former domain is nucleated by the [delta](Ni[sub 3]Nb) precipitates and results in fine-grained microstructure. In the high-temperature DRX domain, carbides dissolve in the matrix and make interstitial carbon atoms available for increasing the rate of dislocation generation for DRX nucleation. It is recommended that IN-718 may be hot-forged initially at 1,200 C and 0.1 s[sup [minus]1] and finish-forged at 950 C and 0.001 s [sup [minus]1] so that fine-grained structure may be achieved. The available forging practice validates these results from processing maps. At temperatures lower than 1,000 C and strain rates higher than 1 s[sup [minus]1], the material exhibits adiabatic shear bands. Also, at temperatures higher than 1150 C and strain rates more than 1 s[sup [minus]1], IN-718 exhibits intercrystalline cracking. Both these regimes may be avoided in hot-working IN-718.

  8. 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

  9. Dominating Role of Ni(0) on the Interface of Ni/NiO for Enhanced Hydrogen Evolution Reaction.

    PubMed

    Wang, Jing; Mao, Shanjun; Liu, Zeyan; Wei, Zhongzhe; Wang, Haiyan; Chen, Yiqing; Wang, Yong

    2017-03-01

    The research of a robust catalytic system based on single NiOx electrocatalyst for hydrogen evolution reaction (HER) remains a huge challenge. Particularly, the factors that dominate the catalytic properties of NiOx-based hybrids for HER have not been clearly demonstrated. Herein, a convenient protocol for the fabrication of NiOx@bamboo-like carbon nanotube hybrids (NiOx@BCNTs) is designed. The hybrids exhibit superb catalytic ability and considerable durability in alkaline solution. A benchmark HER current density of 10 mA cm(-2) has been achieved at an overpotential of ∼79 mV. In combination with the experimental results and density functional theory (DFT) calculations, this for the first time definitely validates that the inherent high Ni(0) ratio and the Ni(0) on the interface of Ni/NiO play a vital role in the outstanding catalytic performance. Especially, the Ni(0) on the interface of Ni/NiO performs superior activity for water splitting compared with that of bulk Ni(0). These conclusions provide guidance for the rational design of the future non-noble metallic catalysts.

  10. Biogeochemical characteristics of Kuan-Tzu-Ling, Chung-Lun and Bao-Lai hot springs in southern Taiwan.

    PubMed

    Maity, Jyoti Prakash; Liu, Chia-Chuan; Nath, Bibhash; Bundschuh, Jochen; Kar, Sandeep; Jean, Jiin-Shuh; Bhattacharya, Prosun; Liu, Jiann-Hong; Atla, Shashi B; Chen, Chien-Yen

    2011-01-01

    Hot springs are the important natural sources of geothermally heated groundwater from the Earth's crust. Kuan-Tzu-Ling (KTL), Chung-Lun (CL) and Bao-Lai (BL) are well-known hot springs in southern Taiwan. Fluid and mud (sediments) samples were collected from the eruption points of three hot springs for detailed biogeochemical characterization. The fluid sample displays relatively high concentrations of Na(+) and Cl(-) compared with K(+), Mg(2+), Ca(2+), NO(2) (-), and SO(4) (2-), suggesting a possible marine origin. The concentrations of Fe, Cr, Mn, Ni, V and Zn were significantly higher in the mud sediments compared with fluids, whereas high concentrations of As, Ba, Cu, Se, Sr and Rb were observed in the fluids. This suggests that electronegative elements were released during sediment-water interactions. High As concentration in the fluids was observed to be associated with low redox (Eh) conditions. The FTIR spectra of the humic acid fractions of the sediments showed the presence of possible functional groups of secondary amines, ureas, urethanesm (amide), and silicon. The sulfate-reducing deltaproteobacterium 99% similar to Desulfovibrio psychrotolerans (GU329907) were rich in the CL hot spring while mesophilic, proteolytic, thiosulfate- and sulfur-reducing bacterium that 99% similar to Clostridium sulfidigenes (GU329908) were rich in the BL hot spring.

  11. Susceptibility to hot corrosion of four nickel-base superalloys, NASA-TRW VIA, B-1900, 713C and IN-738

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.

    1977-01-01

    The susceptibility to hot corrosion of four nickel-base, cast superalloys has been studied at 900 and 1000 C. The test consisted of coating alloy samples with known amounts of Na2SO4 and oxidizing the coated samples isothermally in 1 atmosphere of slowly flowing oxygen, the weight-gain being monitored on a sensitive recording microbalance. Susceptibility to hot corrosion decreased in the order of decreasing molybdenum content of the alloys. Preoxidation of samples before hot-corrosion testing markedly increased the induction period observed prior to the inception of hot corrosion for all alloys tested. X-ray diffraction analyses of the oxide scales were made. All samples that underwent hot corrosion showed the presence of a (Ni,Co)MoO4 layer near the alloy-oxide interface. Several specimens displayed resistance to hot corrosion and these showed NaTaO3 as a prominent feature in their oxide scale. Our results may be interpreted as indicating that molybdenum in an alloy is detrimental, with respect to hot corrosion, while tantalum is beneficial.

  12. Diffusive Interaction Between Ni-Cr-Al Alloys

    NASA Astrophysics Data System (ADS)

    Tkacz-Śmiech, Katarzyna; Danielewski, Marek; Bożek, Bogusław; Berent, Katarzyna; Zientara, Dariusz; Zajusz, Marek

    2017-03-01

    In high-temperature coatings, welded parts, and a range of other applications, components in the contact zone interdiffuse at elevated temperatures and may react to change the phase composition. The diffusion zone can be complex and can consist of sequential layers of intermediate phases, solid solutions, and in the case of multicomponent systems also of multiphase layers. In this work, the interdiffusion in Ni-Cr-Al alloys is studied experimentally and modeled numerically. The diffusion multiples were prepared by hot isostatic pressing and post-annealing at 1473 K (1200 °C). The concentration profiles were measured with wide-line EDS technique which allowed obtaining high-accuracy diffusion paths. The experimental profiles and diffusion paths were compared with numerical results simulated with application of very recent model of interdiffusion in muticomponent-multiphase systems. The calculated and experimental data show good agreement.

  13. Diffusive Interaction Between Ni-Cr-Al Alloys

    NASA Astrophysics Data System (ADS)

    Tkacz-Śmiech, Katarzyna; Danielewski, Marek; Bożek, Bogusław; Berent, Katarzyna; Zientara, Dariusz; Zajusz, Marek

    2017-05-01

    In high-temperature coatings, welded parts, and a range of other applications, components in the contact zone interdiffuse at elevated temperatures and may react to change the phase composition. The diffusion zone can be complex and can consist of sequential layers of intermediate phases, solid solutions, and in the case of multicomponent systems also of multiphase layers. In this work, the interdiffusion in Ni-Cr-Al alloys is studied experimentally and modeled numerically. The diffusion multiples were prepared by hot isostatic pressing and post-annealing at 1473 K (1200 °C). The concentration profiles were measured with wide-line EDS technique which allowed obtaining high-accuracy diffusion paths. The experimental profiles and diffusion paths were compared with numerical results simulated with application of very recent model of interdiffusion in muticomponent-multiphase systems. The calculated and experimental data show good agreement.

  14. Deformation and fatigue behavior of hot dip galvanized coatings

    SciTech Connect

    Camurri, Carlos P. . E-mail: ccamurri@udec.cl; Benavente, Raul G.; Roa, Isidoro S.; Carrasco, Claudia C.

    2005-09-15

    This paper reports on the results of a study of the effect of static and dynamic stresses on hot dip galvanized coatings on SAE 1020 steel substrates. Galvanizing was performed using baths maintained at 450 deg. C, the zinc containing 0.16% Ti and 0.02% Fe and with Al and Ni in the ranges 0-0.20% and 0-0.30%, respectively. Static three-point bend tests were conducted with applied stresses in the range 428-790 MPa. Dynamic bend-fatigue tests involved stresses in the range 228-578 MPa at a cyclic frequency of 0.25 Hz for up to 700 cycles. The total crack density in the coatings was measured before and after the tests using light optical and electron microscopy. The results showed that the crack density increased as the applied stress increased and crack propagation was promoted perpendicular to the substrate. The number of cycles had no effect on the crack density and propagation at stresses lower than 386 MPa. At higher stresses the number of applied cycles contributed only to crack propagation. It was concluded that the best bath composition for preventing fatigue crack propagation is one that minimized the formation of thinner brittle layers in the galvanized coatings.

  15. Comprehensive theoretical studies on the low-lying electronic states of NiF, NiCl, NiBr, and NiI.

    PubMed

    Zou, Wenli; Liu, Wenjian

    2006-04-21

    The low-lying electronic states of the nickel monohalides, i.e., NiF, NiCl, NiBr, and NiI, are investigated by using multireference second-order perturbation theory with relativistic effects taken into account. For the energetically lowest 11 lambda-S states and 26 omega states there into, the potential energy curves and corresponding spectroscopic constants (vertical and adiabatic excitation energies, equilibrium bond lengths, vibrational frequencies, and rotational constants) are reported. The calculated results are grossly in very good agreement with those solid experimental data. In particular, the ground state of NiI is shown to be different from those of NiF, NiCl, and NiBr, being in line with the recent experimental observation. Detailed analyses are provided on those states that either have not been assigned or have been incorrectly assigned by previous experiments.

  16. 40 CFR 68.85 - Hot work permit.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 16 2012-07-01 2012-07-01 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. (b...

  17. 40 CFR 68.85 - Hot work permit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 16 2013-07-01 2013-07-01 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. (b...

  18. The Effectiveness of Hot-deck Procedures in Small Samples.

    ERIC Educational Resources Information Center

    Kaiser, Javaid

    A simulation study was conducted to identify the best hot-deck variation to impute missing values. The three variations included in the study were the hot-deck random, the hot-deck sequential, and the hot-deck distance. The properties of these methods were investigated under three levels of the proportion of incomplete records and four levels…

  19. 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....

  20. Physiological responses during continuous work in hot dry and hot humid environments in Indians

    NASA Astrophysics Data System (ADS)

    Sen Gupta, J.; Swamy, Y. V.; Pichan, G.; Dimri, G. P.

    1984-06-01

    Studies have been conducted on six young healthy heat acclimatised Indians to determine the physiological changes in prolonged continuous work in thermally neutral and in hot dry and hot humid environments. Physiological responses in maximal efforts i.e. Vo2 max, VE max and Cf max were noted. In addition, duration in continuous work at three sub-maximal rate of work in three simulated environments were also noted. Physiological responses like Vo2, VE and Cf were noted every 15 minutes of work. Besides these responses, rectal temperature (Tre), mean skin temperature (Ts) and mean sweat rate were also recorded during continuous work. Results indicated a significant decrease in maximum oxygen uptake capacity (Vo2 max) in heat with no change in maximum exercise ventilation (VE max) and maximum cardiac frequency. However, the fall in Vo2 max was more severe in the hot humid environment than in the hot dry climate. Cardiac frequency at fixed oxygen consumption of 1.0, 1.5 and 2.0 l/min was distinctly higher in the hot humid environment than in the hot dry and comfortable temperature. The duration in continuous physical effort in various grades of activities decreased in hot dry environment from that in the-comfortable climate and further decreased significantly in hot humid environment. The highest rate of sweating was observed during work in humid heat. The mean skin temperature (Ts) showed a fall in all the three rates of work in comfortable and hot dry conditions whereas in hot humid environment it showed a linear rise during the progress of work. The rectal temperature on the other hand maintained a near steady state while working at 65 and 82 watts in comfortable and hot dry environments but kept on rising during work in hot humid environment. At the highest work rate of 98 watts, the rectal temperature showed a steady increase even in the hot dry condition. It was thus concluded from the study that a hot humid climate imposes more constraints on the

  1. Density functional theory study of the interfacial properties of Ni/Ni3Si eutectic alloy

    NASA Astrophysics Data System (ADS)

    Zhao, Yuhong; Wen, Zhiqin; Hou, Hua; Guo, Wei; Han, Peide

    2014-06-01

    In order to clarify the heterogeneous nucleation potential of α-Ni grains on Ni3Si particles in Ni-Ni3Si eutectic alloy, the work of adhesion (Wad), fracture toughness (G), interfacial energy (γi), and electronic structure of the index (0 0 1), (1 1 0) and (1 1 1) Ni/Ni3Si interfaces with two different cohesive manners are investigated using first-principles method based on density functional theory. Results indicate that the center site stacking sequence (OM) is preferable to continue the natural stacking sequence of bulk Ni and Ni3Si. Since OM stacking interfaces have larger Wad, G and γi than that of the top site stacking (OT) interfaces. The Ni/Ni3Si (1 1 0) interface with OM stacking has the best mechanical properties. Therefore, the formation of this interface can improve the stability, ductility and fracture toughness of Ni-Ni3Si eutectic alloy. The calculated interfacial energy of Ni/Ni3Si (0 0 1), (1 1 0) and (1 1 1) interfaces with OM stacking proves the excellent nucleation potency of Ni3Si particles for α-Ni phase from thermodynamic considerations. Besides, the electronic structure and chemical bonding of (1 1 0) interface with OM stacking are also discussed.

  2. {001} Oriented piezoelectric films prepared by chemical solution deposition on Ni foils

    NASA Astrophysics Data System (ADS)

    Yeo, Hong Goo; Trolier-McKinstry, Susan

    2014-07-01

    Flexible metal foil substrates are useful in some microelectromechanical systems applications including wearable piezoelectric sensors or energy harvesters based on Pb(Zr,Ti)O3 (PZT) thin films. Full utilization of the potential of piezoelectrics on metal foils requires control of the film crystallographic texture. In this study, {001} oriented PZT thin films were grown by chemical solution deposition (CSD) on Ni foil and Si substrates. Ni foils were passivated using HfO2 grown by atomic layer deposition in order to suppress substrate oxidation during subsequent thermal treatment. To obtain the desired orientation of PZT film, strongly (100) oriented LaNiO3 films were integrated by CSD on the HfO2 coated substrates. A high level of {001} LaNiO3 and PZT film orientation were confirmed by X-ray diffraction patterns. Before poling, the low field dielectric permittivity and loss tangents of (001) oriented PZT films on Ni are near 780 and 0.04 at 1 kHz; the permittivity drops significantly on poling due to in-plane to out-of-plane domain switching. (001) oriented PZT film on Ni displayed a well-saturated hysteresis loop with a large remanent polarization ˜36 μC/cm2, while (100) oriented PZT on Si showed slanted P-E hysteresis loops with much lower remanent polarizations. The |e31,f| piezoelectric coefficient was around 10.6 C/m2 for hot-poled (001) oriented PZT film on Ni.

  3. Chemical reactivity of Ni-Rh nanowires.

    PubMed

    Schoiswohl, J; Mittendorfer, F; Surnev, S; Ramsey, M G; Andersen, J N; Netzer, F P

    2006-09-22

    The properties of bimetallic Ni-Rh nanowires, fabricated by decorating the steps of vicinal Rh(111) surfaces by stripes of self-assembled Ni adatoms, have been probed by STM, photoemission, and ab initio density functional theory calculations. These Ni-Rh nanowires have specific electronic properties that lead to a significantly enhanced chemical reactivity towards oxygen. As a result, the Ni-Rh nanowires can be oxidized exclusively, generating novel quasi-one-dimensional oxide structures.

  4. Hot carrier relaxation dynamics in zinc selenide

    NASA Astrophysics Data System (ADS)

    Mehendale, Manjusha

    The ultrafast relaxation dynamics of hot carriers are monitored in a high-quality ZnSe epilayer grown on GaAs substrate by employing a novel femtosecond pump-probe differential reflectivity technique which exploits the intrinsic interferometric asymmetric Fabry-Perot sample structure. The ultrashort femtosecond pulses used in these timeresolved pump-probe experiments are derived from a hard-apertured Kerr-lens modelocked Ti:sapphire laser. The effect of pump-laser-induced thermal lensing on the stability and operational characteristics of such solid-state Femtosecond lasers is discussed. A theoretical model, which assumes the exponential cooling of electrons and holes towards the band edge and a simple two parabolic band structure, is used to estimate the hot carrier cooling times for various photoexcited carrier densities. This model shows the results to be consistent with the expected characteristic electronic LO-phonon emission time of 35-40 fs and provide evidence for the influence of a non-equilibrium LO-phonon population, known as ``hot phonon effect'', on the electron cooling dynamics for carrier densities higher than 3 × 1017 cm-3. Another model, which is based on a balance equation approach, is used to analyze the experimental data more accurately, by including the effects of various processes such as screened carrier-phonon, carrier-carrier scattering and hot phonon effects on the relaxation dynamics. Comparison of the experimental data with this latter theoretical model indicates that the observed reduction in the electron cooling rate with increasing carrier density is due to both screening of the Fröhlich interaction and hot phonon effect. Finally, a comparison of hot carrier relaxation processes at various lattice temperatures is presented. This study provides an evidence of a more pronounced hot phonon effect at a lattice temperature of 80K than at 300K, which is complicated by temperature-dependent changes in optical and physical properties of the

  5. Hot streak characterization in serpentine exhaust nozzles

    NASA Astrophysics Data System (ADS)

    Crowe, Darrell S.

    Modern aircraft of the United States Air Force face increasingly demanding cost, weight, and survivability requirements. Serpentine exhaust nozzles within an embedded engine allow a weapon system to fulfill mission survivability requirements by providing denial of direct line-of-sight into the high-temperature components of the engine. Recently, aircraft have experienced material degradation and failure along the aft deck due to extreme thermal loading. Failure has occurred in specific regions along the aft deck where concentrations of hot gas have come in contact with the surface causing hot streaks. The prevention of these failures will be aided by the accurate prediction of hot streaks. Additionally, hot streak prediction will improve future designs by identifying areas of the nozzle and aft deck surfaces that require thermal management. To this end, the goal of this research is to observe and characterize the underlying flow physics of hot streak phenomena. The goal is accomplished by applying computational fluid dynamics to determine how hot streak phenomena is affected by changes in nozzle geometry. The present research first validates the computational methods using serpentine inlet experimental and computational studies. A design methodology is then established for creating six serpentine exhaust nozzles investigated in this research. A grid independent solution is obtained on a nozzle using several figures of merit and the grid-convergence index method. An investigation into the application of a second-order closure turbulence model is accomplished. Simulations are performed for all serpentine nozzles at two flow conditions. The research introduces a set of characterization and performance parameters based on the temperature distribution and flow conditions at the nozzle throat and exit. Examination of the temperature distribution on the upper and lower nozzle surfaces reveals critical information concerning changes in hot streak phenomena due to changes

  6. 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.

  7. On the similarity of the bonding in NiS and NiO

    NASA Technical Reports Server (NTRS)

    Bauschlicher, C. W., Jr.

    1985-01-01

    The bonding in NiS is found to be quite similar to that in NiO, having an ionic contribution arising from the donation of the Ni 4s electron to the S atom and a covalent component arising from bonds between the Ni 3d and the S 3p. The one-electron d bonds are found to be of equal strength for NiO and NiS, but the two-electron d bonds are weaker for NiS.

  8. On the similarity of the bonding in NiS and NiO

    NASA Technical Reports Server (NTRS)

    Bauschlicher, C. W., Jr.

    1985-01-01

    The bonding in NiS is found to be quite similar to that in NiO, having an ionic contribution arising from the donation of the Ni 4s electron to the S atom and a covalent component arising from bonds between the Ni 3d and the S 3p. The one-electron d bonds are found to be of equal strength for NiO and NiS, but the two-electron d bonds are weaker for NiS.

  9. Direct Experimental Probe of the Ni(II)/Ni(III)/Ni(IV) Redox Evolution in LiNi0.5Mn1.5O4 Electrodes

    DOE PAGES

    Qiao, Ruimin; Wray, L. Andrew; Kim, Jung -Hyun; ...

    2015-11-11

    The LiNi0.5Mn1.5O4 spinel is an appealing cathode material for next generation rechargeable Li-ion batteries due to its high operating voltage of ~4.7 V (vs Li/Li+). Although it is widely believed that the full range of electrochemical cycling involves the redox of Ni(II)/(IV), it has not been experimentally clarified whether Ni(III) exists as the intermediate state or a double-electron transfer takes place. Here, combined with theoretical calculations, we show unambiguous spectroscopic evidence of the Ni(III) state when the LiNi0.5Mn1.5O4 electrode is half charged. This provides a direct verification of single-electron-transfer reactions in LiNi0.5Mn1.5O4 upon cycling, namely, from Ni(II) to Ni(III), thenmore » to Ni(IV). Additionally, by virtue of its surface sensitivity, soft X-ray absorption spectroscopy also reveals the electrochemically inactive Ni2+ and Mn2+ phases on the electrode surface. Our work provides the long-awaited clarification of the single-electron transfer mechanism in LiNi0.5Mn1.5O4 electrodes. Furthermore, the experimental results serve as a benchmark for further spectroscopic characterizations of Ni-based battery electrodes.« less

  10. Reaction of amorphous Ni-W and Ni-N-W films with substrate silicon

    NASA Technical Reports Server (NTRS)

    Zhu, M. F.; Suni, I.; Nicolet, M.-A.; Sands, T.

    1984-01-01

    Wiley et al. (1982) have studied sputtered amorphous films of Nb-Ni, Mo-Ni, Si-W, and Si-Mo. Kung et al. (1984) have found that amorphous Ni-Mo films as diffusion barriers between multilayer metallizations on silicon demonstrate good electrical and thermal stability. In the present investigation, the Ni-W system was selected because it is similar to the Ni-Mo system. However, W has a higher silicide formation temperature than Mo. Attention is given to aspects of sample preparation, sample characterization, the interaction between amorphous Ni-W films and Si, the crystallization of amorphous Ni(36)W(64) films on SiO2, amorphous Ni-N-W films, silicide formation and phase separation, and the crystallization of amorphous Ni(36)W(64) and Ni(30)N(21)W(49) layers.

  11. 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)

  12. 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

  13. HOT CELL BUILDING, TRA632. SHIELDING DOOR TO HOT CELL IS ...

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

    HOT CELL BUILDING, TRA-632. SHIELDING DOOR TO HOT CELL IS IN OPEN POSITION. DOOR SLIDES SHUT WITH HELP OF MANUALLY OPERATED CHAIN. STAIRWAY TO MEZZANINE IN VIEW AT LEFT. CAMERA FACES NORTHWEST. INL NEGATIVE NO. 9000. Unknown Photographer, 10/28/1953 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  14. 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

  15. Stability of NiTi-Pd and NiTi-Hf high temperature shape memory alloys

    SciTech Connect

    Zhu, Y.R.; Pu, Z.J.; Li, C.; Wu, K.H.

    1994-09-28

    The thermal cycling tests and high temperature aging tests were performed to characterize the stability of NiTi-Pd and NiTi-Hf high temperature shape memory alloys. These alloys have better stability than NiTi during thermal cycling. In addition, it also found that the NiTi-Pd and NiTi-Hf alloy have a very good stability in high temperature aging.

  16. Electrical and thermal transport in CeNi and LaNi

    NASA Astrophysics Data System (ADS)

    Rudajevová, Alexandra; Vasylyev, Denis; Musil, Ondřej

    2006-05-01

    We have measured the electrical resistivity and thermal conductivity of CeNi, LaNi and La 0.15Ce 0.85Ni in the temperature range 4-400 K simultaneously on the same specimen using the TTO option in PPMS (Quantum Design) facility. Anomalous behaviour of the resistivity and the Lorenz number for CeNi and La 0.15Ce 0.85Ni can be attributed to valence fluctuations.

  17. Green-fuel-mediated synthesis of self-assembled NiO nano-sticks for dual applications—photocatalytic activity on Rose Bengal dye and antimicrobial action on bacterial strains

    NASA Astrophysics Data System (ADS)

    Iyyappa Rajan, P.; Vijaya, J. Judith; Jesudoss, S. K.; Kaviyarasu, K.; Kennedy, L. John; Jothiramalingam, R.; Al-Lohedan, Hamad A.; Vaali-Mohammed, Mansoor-Ali

    2017-08-01

    With aim of promoting the employability of green fuels in the synthesis of nano-scaled materials with new kinds of morphologies for multiple applications, successful synthesis of self-assembled NiO nano-sticks was achieved through a 100% green-fuel-mediated hot-plate combustion reaction. The synthesized NiO nano-sticks show excellent photocatalytic activity on Rose Bengal dye and superior antibacterial potential towards both Gram-positive and Gram-negative bacteria.

  18. 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.

  19. Investigation of hot air balloon fatalities.

    PubMed

    McConnell, T S; Smialek, J E; Capron, R G

    1985-04-01

    The rising popularity of the sport of hot air ballooning has been accompanied by several recent incidents, both in this country and other parts of the world, where mechanical defects and the improper operation of balloons have resulted in several fatalities. A study was conducted to identify the location and frequency of hot air ballooning accidents. Furthermore, the study attempted to identify those accidents that were the result of improper handling on the part of the balloon operators and those that were related to specific defects in the construction of the balloon. This paper presents a background of the sport of hot air ballooning, together with an analysis of the construction of a typical hot air balloon, pointing out the specific areas where defects may occur that could result in a potential fatal balloon crash. Specific attention is given to the two recent balloon crashes that occurred in Albuquerque, N.M., hot air balloon capital of the world, and that resulted in multiple fatalities.

  20. 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)

  1. Subseasonal predictions of eastern US hot weather

    NASA Astrophysics Data System (ADS)

    McKinnon, K. A.; Rhines, A. N.; Tingley, M.; Huybers, P. J.

    2016-12-01

    Midlatitude summertime heat extremes negatively impact human health and agriculture, but are challenging to predict at lead times longer than those of weather models. Longer lead time predictions could emerge from statistical relationships between slowly-varying components of the climate system, such as the ocean or land surface, and specific extreme events. We identify a sea surface temperature (SST) anomaly pattern in the midlatitude Pacific that tends to precede very hot weather in the eastern US, allowing for skillful probabilistic predictions of hot days at lead times up to 50 days. The occurrence of the SST anomaly pattern is associated with the diversion of moisture from the eastern US, priming the region for hot temperatures. More generally, the midlatitude Pacific and eastern US are linked by specific circumglobal circulation anomalies steered by the summer atmospheric wave guide. The role of the summer wave guide in the observed link between midlatitude Pacific SST anomalies and eastern US hot weather is explored through an examination of models in the CMIP5 archive. Models with weaker-than-observed summer jets exhibit SST precursors to hot weather that are distinct from the observed relationship, with greater linkages to the eastern tropical Pacific and similarity to the Pacific Decadal Oscillation.

  2. Kinetics of Ni2Si growth from pure Ni and Ni(V) films on (111) and (100) Si

    NASA Astrophysics Data System (ADS)

    Harith, M. A.; Zhang, J. P.; Campisano, S. U.; Klaar, H.-J.

    1987-01-01

    The kinetics of Ni2Si growth from pure Ni and from Ni0.93V0.07 films on (111) and (100) silicon has been studied by the combination of He+ backscattering, x-ray diffraction, Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) techniques. The activation energies are 1.5 and 1.0 eV for pure Ni and Ni(V) films, respectively while the pre-exponential factors in Ni(V) are 4 5 orders of magnitude smaller than in the pure Ni case. The variations in the measured rates are related to the different grain size of the growing suicide layers. The vanadium is rejected from the silicide layer and piles up at the metalsilicide interface.

  3. Preparation of melt textured Ni-Mn-Ga

    NASA Astrophysics Data System (ADS)

    Pötschke, Martin; Gaitzsch, Uwe; Roth, Stefan; Rellinghaus, Bernd; Schultz, Ludwig

    2007-09-01

    Ni-Mn-Ga alloys are the best-known group of magnetically active alloys, which show magnetic field-induced strain (MFIS) via twin boundary motion. This phenomenon is often referred to as the magnetic shape memory effect. In single crystals, strains of up to 10% have been achieved that way. Up to now, no systematic study of this effect in polycrystals is available. In order to obtain this effect also in polycrystals, stationary casting is employed to achieve coarse-grained, textured samples. Therefore, a hot ceramic mold is mounted on a cold copper plate. Thus, a unidirectional heat flow along the sample axis is realized. The direction of heat flow coincides with the growth direction, which is preferentially [1 0 0]. After solidification, the samples were annealed at high temperature (1000 °C) to ensure chemical homogeneity on a local scale. The samples were cut by spark erosion. In order to allow for a direct investigation of the resulting microstructure by electron backscatter diffraction (EBSD) measurements, an alloy composition with a martensitic transformation below room temperature was chosen (Ni 48Mn 30Ga 22). The transformation temperature was checked by differential scanning calometry (DSC). The orientation of the grains and the preferred growth direction was analyzed using EBSD.

  4. Reclamation and additional alloying of 18Ni(350) maraging steel

    SciTech Connect

    Ahmed, M.; Salam, I.; Nasim, I.; Hussain, S.W.; Hashmi, F.H.; Khan, A.Q. )

    1994-06-01

    The possibility of gainfully utilizing grade 18Ni(350) maraging steel scrap has been investigated, along with the effect of additional alloying with niobium. A vacuum induction melting and casting furnace was used for melting and additional alloying. The cast ingots were hot forged and their properties compared with those of the stock material. The composition of the reprocessed material was found to be within the prescribed range for 18Ni(350) steel, except for some loss in titanium content. The hardness and tensile strength of the recycled steels were similar to those of the stock material. A slight decrease in hardness in the aged condition could be attributed to loss of titanium during remelting. Charpy V-notch impact testing indicated significantly higher toughness in the remelted material; this has been attributed to a homogeneous, refined microstructure and a lower level of inclusions. Additional alloying with 2% Nb not only improved the mechanical properties but also affected the amount of reverted austenite obtained after aging.

  5. Kinetics of Ni Sorption in Soils: Roles of Soil Organic Matter and Ni Precipitation

    SciTech Connect

    Shi, Zhenqing; Peltier, Edward; Sparks, Donald L.

    2012-12-10

    The kinetics of Ni sorption to two Delaware agricultural soils were studied to quantitatively assess the relative importance of Ni adsorption on soil organic matter (SOM) and the formation of Ni layered double hydroxide (Ni-LDH) precipitates using both experimental studies and kinetic modeling. Batch sorption kinetic experiments were conducted with both soils at pH 6.0, 7.0, and 7.5 from 24 h up to 1 month. Time-resolved Ni speciation in soils was determined by X-ray absorption spectroscopy (XAS) during the kinetic experiments. A kinetics model was developed to describe Ni kinetic reactions under various reaction conditions and time scales, which integrated Ni adsorption on SOM with Ni-LDH precipitation in soils. The soil Ni speciation (adsorbed phases and Ni-LDH) calculated using the kinetics model was consistent with that obtained through XAS analysis during the sorption processes. Under our experimental conditions, both modeling and XAS results demonstrated that Ni adsorption on SOM was dominant in the short term and the formation of Ni-LDH precipitates accounted for the long-term Ni sequestration in soils, and, more interestingly, that the adsorbed Ni may slowly transfer to Ni-LDH phases with longer reaction times.

  6. Synthesis and catalytic performance of SiO2@Ni and hollow Ni microspheres

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Liu, Yanhua; Shi, Xueting; Yu, Zhengyang; Feng, Libang

    2016-11-01

    Nickel (Ni) catalyst has been widely used in catalytic reducing reactions such as catalytic hydrogenation of organic compounds and catalytic reduction of organic dyes. However, the catalytic efficiency of pure Ni is low. In order to improve the catalytic performance, Ni nanoparticle-loaded microspheres can be developed. In this study, we have prepared Ni nanoparticle-loaded microspheres (SiO2@Ni) and hollow Ni microspheres using two-step method. SiO2@Ni microspheres with raspberry-like morphology and core-shell structure are synthesized successfully using SiO2 microsphere as a template and Ni2+ ions are adsorbed onto SiO2 surfaces via electrostatic interaction and then reduced and deposited on surfaces of SiO2 microspheres. Next, the SiO2 cores are removed by NaOH etching and the hollow Ni microspheres are prepared. The NaOH etching time does no have much influence on the crystal structure, shape, and surface morphology of SiO2@Ni; however, it can change the phase composition evidently. The hollow Ni microspheres are obtained when the NaOH etching time reaches 10 h and above. The as-synthesized SiO2@Ni microspheres exhibit much higher catalytic performance than the hollow Ni microspheres and pure Ni nanoparticles in the catalytic reduction of methylene blue. Meanwhile, the SiO2@Ni catalyst has high stability and hence it can be recycled for reuse.

  7. Kinetics of Ni sorption in soils: roles of soil organic matter and Ni precipitation.

    PubMed

    Shi, Zhenqing; Peltier, Edward; Sparks, Donald L

    2012-02-21

    The kinetics of Ni sorption to two Delaware agricultural soils were studied to quantitatively assess the relative importance of Ni adsorption on soil organic matter (SOM) and the formation of Ni layered double hydroxide (Ni-LDH) precipitates using both experimental studies and kinetic modeling. Batch sorption kinetic experiments were conducted with both soils at pH 6.0, 7.0, and 7.5 from 24 h up to 1 month. Time-resolved Ni speciation in soils was determined by X-ray absorption spectroscopy (XAS) during the kinetic experiments. A kinetics model was developed to describe Ni kinetic reactions under various reaction conditions and time scales, which integrated Ni adsorption on SOM with Ni-LDH precipitation in soils. The soil Ni speciation (adsorbed phases and Ni-LDH) calculated using the kinetics model was consistent with that obtained through XAS analysis during the sorption processes. Under our experimental conditions, both modeling and XAS results demonstrated that Ni adsorption on SOM was dominant in the short term and the formation of Ni-LDH precipitates accounted for the long-term Ni sequestration in soils, and, more interestingly, that the adsorbed Ni may slowly transfer to Ni-LDH phases with longer reaction times.

  8. Evaluation of hot corrosion of 8YSZ coatings elaborated by suspension plasma spraying

    NASA Astrophysics Data System (ADS)

    González-Hernández, A. G.; Ageorges, H.; López-Gómez, M. E.

    2017-01-01

    In this paper, the evaluation microscopic of hot corrosion of 8mol% Yttria Stabilized Zirconia (8YSZ) coatings was studied in the presence of V2O5 and Na2SO4 as corrosive molten salt, for 40h at 1050°C. First, the substrates of Inconel 718 super-alloy were sprayed with a NiCrCoAl-Y2O3 bond coat by atmospheric plasma spraying (APS). Then this bond coat was polished for elaborated the 8YSZ layer by suspension plasma spraying (SPS). The microstructure of the cross-section and surface of the coating was evaluated by scanning electron microscopy (SEM). After the hot corrosion test, the delamination of 8YSZ coatings was occurred in the ceramic layer due to the creation of stress resulting from the chemical reaction between the molten salts and the yttria (Y2O3) of 8YSZ coating at high temperature. According to EDS-SEM analysis, the evaluation of fractured sections of 8YSZ coating showed mainly the formation of crystals composed by Y, V, O and the surface was mainly composed by Zr and O. Those crystals can be related with the tetragonal phase of YVO4, which they were commonly found by other researchers in studies of hot corrosion of YSZ-based TBCs when its surface reacts with the corrosive salts.

  9. Measuring hot flash phenomenonology using ambulatory prospective digital diaries.

    PubMed

    Fisher, William I; Thurston, Rebecca C

    2016-11-01

    This study provides the description, protocol, and results from a novel prospective ambulatory digital hot flash phenomenon diary. This study included 152 midlife women with daily hot flashes who completed an ambulatory electronic hot flash diary continuously for the waking hours of three consecutive days. In this diary, women recorded their hot flashes and accompanying characteristics and associations as the hot flashes occurred. Self-reported hot flash severity on the digital diaries indicated that the majority of hot flashes were rated as mild (41.3%) or moderate (43.7%). Severe (13.1%) and very severe (1.8%) hot flashes were less common. Hot flash bother ratings were rated as mild (43%), or moderate (33.5%), with fewer hot flashes reported bothersome (17.5%) or very bothersome (6%). The majority of hot flashes were reported as occurring on the face (78.9%), neck (74.7%), and chest (61.3%). Of all reported hot flashes, 32% occurred concurrently with prickly skin, 7% with anxiety, and 5% with nausea. A novel finding from the study was that 38% of hot flashes were accompanied by a premonitory aura. A prospective electronic digital hot flash diary allows for a more precise quantitation of hot flashes while overcoming many of the limitations of commonly used retrospective questionnaires and paper diaries. Unique insights into the phenomenology, loci, and associated characteristics of hot flashes were obtained using this device. The digital hot flash phenomenology diary is recommended for future ambulatory studies of hot flashes as a prospective measure of the hot flash experience.

  10. Innovative materials: the NiTi alloys in orthodontics.

    PubMed

    Airoldi, G; Riva, G

    1996-01-01

    Since ten years the NiTi alloys have gained an ever increasing place in orthodontic practice: that is due to their peculiar mechanical properties ascribed to a martensitic thermoelastic transformation which can be thermally or, in a proper temperature range, stress-induced. In the last case, when martensite is stress-induced at body temperature, the stress-strain behaviour is pseudoelastic with large deformations gained or recovered at constant stress, respectively in direct/reverse transformation: this behaviour exploited in orthodontics allowed to overcome the drawbacks intrinsic to the use of conventional alloys as stainless steel or Co-Mo alloys, where small displacements can be achieved at decreasing loads. From the phase state diagram of NiTi alloys it appears that at body temperature they are stable, but out of equilibrium: thermal treatments at intermediate temperatures can therefore modify the equilibrium state and as a consequence the transformation temperatures respect to body temperature. That allows to modify the recovery stress level according to the requirements of practice and thus disclosing new roads: the capability to foresee NiTi archwires pre-programmed in different sections, with a personalized scheme. Attention has not currently been paid to the modifications in the recovery stress induced by a temperature change inside the oral cavity. Recent results have shown that the thermal changes in the oral cavity induced by cold/hot liquid intake can considerably modify the stress level to which the dentition is exposed: though confined to the time extent connected with drinking, similar effects can be expected also for meals intake and should be taken into account for a correct procedure.

  11. 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.

  12. Hot electron plasmon-protected solar cell.

    PubMed

    Kong, J; Rose, A H; Yang, C; Wu, X; Merlo, J M; Burns, M J; Naughton, M J; Kempa, K

    2015-09-21

    A solar cell based on a hot electron plasmon protection effect is proposed and made plausible by simulations, non-local modeling of the response, and quantum mechanical calculations. In this cell, a thin-film, plasmonic metamaterial structure acts as both an efficient photon absorber in the visible frequency range and a plasmonic resonator in the IR range, the latter of which absorbs and protects against phonon emission the free energy of the hot electrons in an adjacent semiconductor junction. We show that in this structure, electron-plasmon scattering is much more efficient than electron-phonon scattering in cooling-off hot electrons, and the plasmon-stored energy is recoverable as an additional cell voltage. The proposed structure could become a prototype of a new generation of high efficiency solar cells.

  13. Hot exciton dissociation in polymer solar cells.

    PubMed

    Grancini, G; Maiuri, M; Fazzi, D; Petrozza, A; Egelhaaf, H-J; Brida, D; Cerullo, G; Lanzani, G

    2013-01-01

    The standard picture of photovoltaic conversion in all-organic bulk heterojunction solar cells predicts that the initial excitation dissociates at the donor/acceptor interface after thermalization. Accordingly, on above-gap excitation, the excess photon energy is quickly lost by internal dissipation. Here we directly target the interfacial physics of an efficient low-bandgap polymer/PC(60)BM system. Exciton splitting occurs within the first 50 fs, creating both interfacial charge transfer states (CTSs) and polaron species. On high-energy excitation, higher-lying singlet states convert into hot interfacial CTSs that effectively contribute to free-polaron generation. We rationalize these findings in terms of a higher degree of delocalization of the hot CTSs with respect to the relaxed ones, which enhances the probability of charge dissociation in the first 200 fs. Thus, the hot CTS dissociation produces an overall increase in the charge generation yield.

  14. Kepler constraints on planets near hot Jupiters

    PubMed Central

    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.; Quinn, Samuel N.

    2012-01-01

    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. PMID:22566651

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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. Angular response of hot wire probes

    NASA Astrophysics Data System (ADS)

    di Mare, L.; Jelly, T. O.; Day, I. J.

    2017-03-01

    A new equation for the convective heat loss from the sensor of a hot-wire probe is derived which accounts for both the potential and the viscous parts of the flow past the prongs. The convective heat loss from the sensor is related to the far-field velocity by an expression containing a term representing the potential flow around the prongs, and a term representing their viscous effect. This latter term is absent in the response equations available in the literature but is essential in representing some features of the observed response of miniature hot-wire probes. The response equation contains only four parameters but it can reproduce, with great accuracy, the behaviour of commonly used single-wire probes. The response equation simplifies the calibration the angular response of rotated slanted hot-wire probes: only standard King’s law parameters and a Reynolds-dependent drag coefficient need to be determined.